WorldWideScience

Sample records for hydrocarbon gas seepage

  1. Hyperspectral reflectance of vegetation affected by underground hydrocarbon gas seepage

    NARCIS (Netherlands)

    Noomen, M.F.

    2007-01-01

    Anomalous concentrations of natural gas in the soil may be sourced from leaking underground gas pipelines or from natural microseepages. Due to the explosive nature of hydrocarbon gases, early detection of these gases is essential to avoid dangerous situations. It is known that natural gas in the

  2. ASSESSMENT OF HYDROCARBON SEEPAGE DETECTION METHODS ON THE FORT PECK RESERVATION, NORTHEAST MONTANA

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence M. Monson

    2003-06-30

    Surface exploration techniques have been employed in separate study areas on the Fort Peck Reservation in northeastern Montana. Anomalies associated with hydrocarbon seepage are documented in all three areas and a variety of surface exploration techniques can be compared. In a small area with established production, Head Gas and Thermal Desorption methods best match production; other methods also map depletion. In a moderate-size area that has prospects defined by 3D seismic data, Head Gas along with Microbial, Iodine, and Eh soil anomalies are all associated with the best hydrocarbon prospect. In a large area that contains many curvilinear patterns observed on Landsat images, that could represent micro-seepage chimneys, results are inconclusive. Reconnaissance mapping using Magnetic Susceptibility has identified a potential prospect; subsequent Soil Gas and Head Gas surveys suggest hydrocarbon potential. In the final year of this project the principle contractor, the Fort Peck Tribes, completed a second survey in the Wicape 3D Seismic Prospect Area (also known as Area 6 in Phase I of the project) and sampled several Landsat image features contained in the Smoke Creek Aeromag Anomaly Area (also known as Area 1 in Phase II of the project). Methods determined to be most useful in Phases I and II, were employed in this final Phase III of the study. The Southwest Wicape seismic anomaly was only partially confirmed. The abundant curvilinears proposed to be possible hydrocarbon micro-seepage chimneys in the Smoke Creek Area were not conclusively verified as such. Insufficient sampling of background data precludes affirmative identification of these mostly topographic Landsat features as gas induced soil and vegetation anomalies. However relatively higher light gas concentrations were found associated with some of the curvilinears. Based on the findings of this work the Assiniboine & Sioux Tribes of the Fort Peck Reservation intend to utilize surface hydrocarbon

  3. Gas seepage in the Northern Adriatic Sea

    Science.gov (United States)

    Matilde Ferrante, Giulia; Donda, Federica; Volpi, Valentina; Tinivella, Umberta

    2017-04-01

    In the Northern Adriatic Sea, the occurrence of gas seepage has been widely documented. However, the origin of seeping gas was not clearly constrained. Geophysical data with different scale of resolution, i.e. multichannel seismic profiles, CHIRP and morpho-bathymetry data collected in 2009 and 2014 by OGS reveal that several the gas-enriched fluid vents are deeply rooted. In fact, the entire Plio-Quaternary succession is characterized by widespread seismic anomalies represented by wipe-out zones and interpreted as gas chimneys. They commonly root at the base of the Pliocene sequence but also within the Paleogene succession, where they appear to be associated to deep-seated, Mesozoic-to-Paleogene faults. These chimneys originate and terminate at different stratigraphic levels; they also commonly reach the seafloor, where rock outcrops interpreted as authigenic carbonate deposits have been recognized. In places, gas is then capable to escape in the water column as shown by numerous gas flares. On going studies are addressed to: 1. re-examining the structural setting of the study area, in order to verify a possible structural control on chimney distribution and gas migration; 2. performing geochemical analysis on gas which have been sampled in some key emission points; 3. a quantitative analysis of some selected boreholes well logs (made available through the public VidePi database (www.videpi.com)) aimed to estimate the amount of gas present in sediments. This work presents the preliminary results regarding the latter aspect of our research. In a first instance, for each selected borehole the geophysical logs have been digitized. This procedure consists in a manual picking of curves, in a set system of reference. Static corrections for vertical offset are made at this stage. Logs are then divided by type and converted in common scales, amplifications and units. Every log is resampled in order to cut high frequencies not useful in the comparison with seismic data

  4. Detection and Origin of Hydrocarbon Seepage Anomalies in the Barents Sea

    Science.gov (United States)

    Polteau, Stephane; Planke, Sverre; Stolze, Lina; Kjølhamar, Bent E.; Myklebust, Reidun

    2016-04-01

    We have collected more than 450 gravity cores in the Barents Sea to detect hydrocarbon seepage anomalies and for seismic-stratigraphic tie. The cores are from the Hoop Area (125 samples) and from the Barents Sea SE (293 samples). In addition, we have collected cores near seven exploration wells. The samples were analyzed using three different analytical methods; (1) the standard organic geochemical analyzes of Applied Petroleum Technologies (APT), (2) the Amplified Geochemical Imaging (AGI) method, and (3) the Microbial Prospecting for Oil and Gas (MPOG) method. These analytical approaches can detect trace amounts of thermogenic hydrocarbons in the sediment samples, and may provide additional information about the fluid phases and the depositional environment, maturation, and age of the source rocks. However, hydrocarbon anomalies in seabed sediments may also be related to shallow sources, such as biogenic gas or reworked source rocks in the sediments. To better understand the origin of the hydrocarbon anomalies in the Barents Sea we have studied 35 samples collected approximately 200 m away from seven exploration wells. The wells included three boreholes associated with oil discoveries, two with gas discoveries, one dry well with gas shows, and one dry well. In general, the results of this case study reveal that the oil wells have an oil signature, gas wells show a gas signature, and dry wells have a background signature. However, differences in results from the three methods may occur and have largely been explained in terms of analytical measurement ranges, method sensitivities, and bio-geochemical processes in the seabed sediments. The standard geochemical method applied by APT relies on measuring the abundance of compounds between C1 to C5 in the headspace gas and between C11 to C36 in the sediment extracts. The anomalies detected in the sediment samples from this study were in the C16 to C30 range. Since the organic matter yields were mostly very low, the

  5. Hydrocarbon Seepage during the Boreal Base Cretaceous Hot Shale Event

    Science.gov (United States)

    Hammer, Ø.; Hryniewicz, K.; Nakrem, H. A.; Little, C.

    2014-12-01

    We have identified a number of carbonate bodies interpreted as seep-related from near the Jurassic-Cretaceous boundary in Svalbard, arctic Norway. The paleoseeps discovered so far occur over 50 km along strike, representing a seepage field of considerable extent. Ammonites indicate a base Cretaceous (Late Volgian to Late Ryazanian) age. The carbonate bodies are highly fossiliferous, with a very diverse fauna consisting mainly of normal-marine species but also seep-restricted taxa. Carbonate d13C isotopes reach -46‰, which, considering mixture with seawater-derived carbon, is interpreted as indicating a biogenic methane source. It is of interest to note the correlation of this paleoseepage with an episode of extremely high burial of organic matter near the Jurassic-Cretaceous boundary, noted both in Svalbard (top Slottsmøya Member of the Agardhfjellet Formation), in the Barents Sea (Hekkingen Formation) and in the North Sea (Mandal Formation), possibly providing a shallow source for biogenic gas. Together with near contemporaneous events in the Boreal Realm such as ongoing rifting, the base Cretaceous unconformity, the Mjølnir meteorite impact and a possible minor extinction event, these finds contribute to the impression of the Jurassic-Cretaceous boundary as a highly dynamic and interesting time in the North Atlantic area.

  6. Seepage system of oil-gas and its exploration in Yinggehai Basin located at northwest of South China Sea

    Directory of Open Access Journals (Sweden)

    Jiaxiong He

    2017-02-01

    Full Text Available Seepage systems of oil-gas in Yinggehai Basin are divided into two types, namely: “micro-seepage”, which is presented by gas chimneys and pockmarks; and “macro-seepage”, which is also called oil-gas outflow; and, in addition, the combination of the two basic types. Among the oil seepage systems, the combined seepage system at Yingdong Slope of Yinggehai Basin is the most eye-catching, and gas chimneys and pockmarks micro-leakage systems in mud diapir zones in the central part of the basin are very common. Both the indications of large-scale oil-gas outflow at Yingdong Slope, which have been booming for a hundred years; and the occurrence of pockmarks at the central mud diapir belt, along with the chaotic seismic reflection of widely-distributed shallow gas chimneys—have shown that hydrocarbon in this area is sufficient and oil-gas is now in dynamic equilibrium of the processes of accumulation, migration, gathering and dispersing. It builds up good conditions for the accumulation, migration, gathering and reserving of oil and gas. However, it must be noted that the results of oil-gas exploration at Yingdong Slope didn't turn out to be satisfactory, despite the presence of oil-gas outflow and gas chimney combined seepage systems. So, strengthen synthesized analysis and study on oil-gas seepage systems and on the conditions for accumulation, migration, gathering and dispersing; the forecasting and evaluation to the advantageous conditions for enriched oil and gas zones; and trap preservation in accordance with the dynamic balance theories; are of significant importance for purposes of exploration.

  7. Methane gas seepage - Disregard of significant water column filter processes?

    Science.gov (United States)

    Schneider von Deimling, Jens; Schmale, Oliver

    2016-04-01

    Marine methane seepage represents a potential contributor for greenhouse gas in the atmosphere and is discussed as a driver for climate change. The ultimate question is how much methane is released from the seafloor on a global scale and what fraction may reach the atmosphere? Dissolved fluxes from methane seepage sites on the seabed were found to be very efficiently reduced by benthic microbial oxidation, whereas transport of free gas bubbles from the seabed is considered to bypass the effective benthic methane filter. Numerical models are available today to predict the fate of such methane gas bubble release to the water column in regard to gas exchange with the ambient water column, respective bubble lifetime and rise height. However, the fate of rising gas bubbles and dissolved methane in the water column is not only governed by dissolution, but is also affected by lateral oceanographic currents and vertical bubble-induced upwelling, microbial oxidation, and physico-chemical processes that remain poorly understood so far. According to this gap of knowledge we present data from two study sites - the anthropogenic North Sea 22/4b Blowout and the natural Coal Oil point seeps - to shed light into two new processes gathered with hydro-acoustic multibeam water column imaging and microbial investigations. The newly discovered processes are hereafter termed Spiral Vortex and Bubble Transport Mechanism. Spiral Vortex describes the evolution of a complex vortical fluid motion of a bubble plume in the wake of an intense gas release site (Blowout, North Sea). It appears very likely that it dramatically changes the dissolution kinetics of the seep gas bubbles. Bubble Transport Mechanism prescribes the transport of sediment-hosted bacteria into the water column via rising gas bubbles. Both processes act as filter mechanisms in regard to vertical transport of seep related methane, but have not been considered before. Spiral Vortex and Bubble Transport Mechanism represent the

  8. Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

    Science.gov (United States)

    Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard

    2016-08-01

    Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1-2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

  9. Surface and subsurface expressions of gas seepage to the seabed – examples from the Southern North Sea

    NARCIS (Netherlands)

    Schroot, B.M.; Klaver, G.T.; Schüttenhelm, R.T.E.

    2005-01-01

    Expressions of gas seepage observable within North Sea seismic and acoustic data include seabed pockmarks, seepage plumes in the water column, acoustic blanking, shallow enhanced reflectors, and shallow seismic chimneys. Three areas were selected for a marine survey in

  10. Characterization of seafloor pockmark seepage of hydrocarbons employing fractal: A case study from the western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Dandapath, S.; Chakraborty, B.; Maslov, N.; Karisiddaiah, S.M.; Ghosh, D.; Fernandes, W.A.; Menezes, A.

    of pockmark related seepages. The study area lies 102 km west off Marmagao along the central west coast of India which contains pre-dominantly (70%) gas-charged sediments. Comparison between the estimated self-similar fractals reveals...

  11. Natural Gas Seepage Along the Edge of the Aquitaine Shelf (France): Origin and Flux Measurements

    Science.gov (United States)

    Ruffine, L.; Donval, J. P.; Battani, A.; Bignon, L.; Croguennec, C.; Caprais, J. C.; Birot, D.; Bayon, G.; Lantéri, N.; Levaché, D.; Dupré, S.

    2014-12-01

    A newly discovered and highly active seepage area has been acoustically mapped at the western edge of the Aquitaine Shelf in the Bay of Biscay [Dupré et al., 2014]. Three selected seeping sites have been investigated with a Remotely Operated Vehicle. All sites were characterized by vigorous gas emissions, and the occurrence of massive carbonate crusts and bacterial mats at the seafloor. Nine seeps have been sampled with the PEGAZ sampler. The latter allowed gas-bubble sampling and preservation at in situpressure, together with gas-flux measurement through its graduated transparent cone. The C2+ fraction of the gas samples accounts for less than 0.06 %-mol of the total composition. Both the abundance of methane and dD and d13C isotopic analyses of the hydrocarbons indicate a biogenic source generated by microbial reduction of carbon dioxide [Whiticar et al., 1986]. The analyses of the associated noble gases also provide further support for a shallow-depth generation. While sharing the same origin, the collected samples are different in other respects, such as the measured d13C values for carbon dioxide and the hydrocarbons. This is the case in particular for methane, with displays values in between -66.1 and -72.7 ‰. We hypothesized that such variations are the result of multiple gas-transport processes along with the occurrence of hydrocarbon oxidation at different rates within the sedimentary column. The measured gas fluxes are extremely heterogeneous from one seep to another, ranging from 18 to 193 m3.yr-1. These values will be discussed in detail by comparing them with values obtained from different measurement techniques at other gas-seeping sites. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. References:Dupré, S., L. Berger, N. Le Bouffant, C. Scalabrin, and J. F. Bourillet (2014), Fluid emissions at the Aquitaine Shelf (Bay of Biscay, France): a biogenic origin or

  12. Seepage law and permeability calculation of coal gas based on Klinkenberg effect

    Institute of Scientific and Technical Information of China (English)

    WANG Deng-ke; WEI Jian-ping; FU Qi-chao; LIU Yong; XIAYu-ling

    2015-01-01

    Focused on the Klinkenberg effect on gas seepage, the independently developed triaxial experimental system of gas seepage was applied to conduct research on the seepage characteristics of coal seam gas. By means of experimental data analysis and theoretical derivation, a calculation method of coal seam gas permeability was proposed, which synthesized the respective influences of gas dynamic viscosity, compressibility factor and Klinkenberg effect. The study results show that the Klinkenberg effect has a significant influence on the coal seam gas seepage, the permeability estimated with the method considering the Klinkenberg effect is correct, and this permeability can fully reflect the true seepage state of the gas. For the gas around the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability may be ignored. For the gas deviating far away from the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability must be considered. The research results have certain guiding significance in forming a correct understanding of the Klinkenberg effect and selecting a more accurate calculation method for the permeability of coal containing gas.

  13. Gas seepage equation of deep mined coal seams and its application

    Institute of Scientific and Technical Information of China (English)

    HU Guo-zhong; WANG Hong-tu; TAN Hai-xiang; FAN Xiao-gang; YUAN Zhi-gang

    2008-01-01

    In order to obtain a gas seepage law of deep mined coal seams, according to the properties of eoalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coalbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accurately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.

  14. A coupling model for gas diffusion and seepage in SRV section of shale gas reservoirs

    Directory of Open Access Journals (Sweden)

    Shusheng Gao

    2017-03-01

    Full Text Available A prerequisite to effective shale gas development is a complicated fracture network generated by extensive and massive fracturing, which is called SRV (stimulated reservoir volume section. Accurate description of gas flow behaviors in such section is fundamental for productivity evaluation and production performance prediction of shale gas wells. The SRV section is composed of bedrocks with varying sizes and fracture networks, which exhibit different flow behaviors – gas diffusion in bedrocks and gas seepage in fractures. According to the porosity and permeability and the adsorption, diffusion and seepage features of bedrocks and fractures in a shale gas reservoir, the material balance equations were built for bedrocks and fractures respectively and the continuity equations of gas diffusion and seepage in the SRV section were derived. For easy calculation, the post-frac bedrock cube was simplified to be a sphere in line with the principle of volume consistency. Under the assumption of quasi-steady flow behavior at the cross section of the sphere, the gas channeling equation was derived based on the Fick's laws of diffusion and the density function of gas in bedrocks and fractures. The continuity equation was coupled with the channeling equation to effectively characterize the complicated gas flow behavior in the SRV section. The study results show that the gas diffusivity in bedrocks and the volume of bedrocks formed by volume fracturing (or the scale of fracturing jointly determines the productivity and stable production period of a shale gas well. As per the actual calculation for the well field A in the Changning–Weiyuan Block in the Sichuan Basin, the matrix has low gas diffusivity – about 10−5 cm2/s and a large volume with an equivalent sphere radius of 6.2 m, hindering the gas channeling from bedrocks to fractures and thereby reducing the productivity of the shale gas well. It is concluded that larger scale of volume fracturing

  15. Study on law of raw coal seepage during loading process at different gas pressures

    Institute of Scientific and Technical Information of China (English)

    Meng Junqing; Nie Baisheng; Zhao Bi; Ma Yechao

    2015-01-01

    In order to reveal the law of raw coal seepage at different gas pressures, the gravity constant load seepage experimental system was developed and used. The law of raw coal seepage at different gas pressures with He, N2 and CO2 was investigated. The results show that, in a given state of stress during the experiment, with the increase of gas pressure, the permeability of raw coal sample prone to outburst exhibits a significantly decrease, and then exhibits an increasing trend when reaching the extreme point. The law of Klingberg coefficient related to the stress state and the gas adsorption properties was also obtained. Under the same experimental conditions, the Klingberg coefficient of He is greater than that of N2; and the Klingberg coefficient of CO2 has minimum value; so the stronger the gas adsorption is, the smaller the Klingberg coefficient of gas goes. Klinkenberg coefficient decreases with the increase of effective stress. Under the same conditions, the permeability of He is greater than that of N2; the permeability of CO2 has minimum value;so the stronger the gas adsorption is, the lower the permeability of the coal sample goes. The results have important significance in revealing the mechanism of gas seepage, predicting coal mine gas disaster, and gas drainage and safety production.

  16. Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

    OpenAIRE

    Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard

    2016-01-01

    Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls...

  17. Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

    OpenAIRE

    Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard

    2016-01-01

    Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in wat...

  18. Albedo and land surface temperature shift in hydrocarbon seepage potential area, case study in Miri Sarawak Malaysia

    Science.gov (United States)

    Suherman, A.; Rahman, M. Z. A.; Busu, I.

    2014-02-01

    The presence of hydrocarbon seepage is generally associated with rock or mineral alteration product exposures, and changes of soil properties which manifest with bare development and stress vegetation. This alters the surface thermodynamic properties, changes the energy balance related to the surface reflection, absorption and emission, and leads to shift in albedo and LST. Those phenomena may provide a guide for seepage detection which can be recognized inexpensively by remote sensing method. District of Miri is used for study area. Available topographic maps of Miri and LANDSAT ETM+ were used for boundary construction and determination albedo and LST. Three land use classification methods, namely fixed, supervised and NDVI base classifications were employed for this study. By the intensive land use classification and corresponding statistical comparison was found a clearly shift on albedo and land surface temperature between internal and external seepage potential area. The shift shows a regular pattern related to vegetation density or NDVI value. In the low vegetation density or low NDVI value, albedo of internal area turned to lower value than external area. Conversely in the high vegetation density or high NDVI value, albedo of internal area turned to higher value than external area. Land surface temperature of internal seepage potential was generally shifted to higher value than external area in all of land use classes. In dense vegetation area tend to shift the temperature more than poor vegetation area.

  19. Bottom Simulating Reflector and Gas Seepage in Okinawa Trough: Evidence of Gas Hydrate in an Active Back-Arc Basin

    Institute of Scientific and Technical Information of China (English)

    Luan Xiwu; Kelin Wang; Roy Hyndman; Eleanor Willoughby

    2008-01-01

    To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea (ECS) shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector (BSR) occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural "anomalies" are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation:to help gather enough methane into a small area and to modulate the thermal regime.

  20. Unifying diffusion and seepage for nonlinear gas transport in multiscale porous media

    Science.gov (United States)

    Song, Hongqing; Wang, Yuhe; Wang, Jiulong; Li, Zhengyi

    2016-09-01

    We unify the diffusion and seepage process for nonlinear gas transport in multiscale porous media via a proposed new general transport equation. A coherent theoretical derivation indicates the wall-molecule and molecule-molecule collisions drive the Knudsen and collective diffusive fluxes, and constitute the system pressure across the porous media. A new terminology, nominal diffusion coefficient can summarize Knudsen and collective diffusion coefficients. Physical and numerical experiments show the support of the new formulation and provide approaches to obtain the diffusion coefficient and permeability simultaneously. This work has important implication for natural gas extraction and greenhouse gases sequestration in geological formations.

  1. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  2. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  3. A conceptual model for hydrocarbon accumulation and seepage processes inside Chapopote asphalt volcanism site, Southern Gulf of Mexico: from high resolution seismic point of view

    Science.gov (United States)

    Ding, F.; Spiess, V.; Fekete, N.; Keil, H.; Bohrmann, G.

    2007-05-01

    As part of the German R/V Meteor M67/2 expedition in 2006 to the southern Gulf of Mexico, a set of 2D high resolution seismic profiles was acquired across the Chapopote knoll to study sea floor asphalt occurrences and their origin. Based on regional seismic stratigraphy studies, correlated to DSDP sites, a higher reflective coarse grained sediment unit of Late Miocene age is identified as a potential shallow gas reservoir, overlain by a low permeability fine grained Pliocene and Pleistocene cover. As a result of salt diapirism, local uplift has caused reduced accumulation rates above the diaper since the late Pliocene, while the rates had been uniform throughout the area before. This has further improved the seal properties, since more fine grained material deposited in elevated locations. Nevertheless, on the crest of Chapopote, sediments above the coarse sediment unit are only around 150-75 m thick. Since oil and gas production can well be expected at depth in Jurassic and Tertiary source rocks, the presence of high amplitude reflector packages within the reservoir unit is interpreted as a result of the presence of hydrocarbons. This interpretation is further supported by the observation that some reflectors are cross-cutting and/or reveal a drop in instantaneous frequency. But, the thin seal above the reservoir unit, located directly underneath a widespread occurrence of asphalts at the sea floor, probably facilitates the leakage of hydrocarbons trapped inside the reservoir through a ~ 750 m wide acoustically chaotic zone partly aided by faulting. Since the top of Chapopote shows a high structural complexity, more seepage sites may exist beyond where seafloor asphalts have been found so far. Evolution and structure of the migration and reservoir system, which may be deep rooted, will be discussed both with respect to shallow gas and asphalt occurrences.

  4. Authigenic carbonates related to gas seepage structures in the sea of Okhotsk NE offshore Sakhalin : results from the Chaos project

    Energy Technology Data Exchange (ETDEWEB)

    Krylov, A.; Hachikubo, A.; Minami, H.; Nunokawa, Y.; Shoji, H. [Kitami Inst. of Technology, Kitami (Japan); Logvina, E.; Mazurenko, L.; Matveeva, T. [VNIIOkeangeologia, St. Petersburg (Russian Federation); Obzhirov, A. [V.I. Il' ichev Pacific Oceanological Inst. of FEB RAS, Vladivostok (Russian Federation); Jin, Y.K. [Korea Polar Research Inst., Incheon (Korea, Republic of)

    2008-07-01

    The Derugin Basin in Russia contains large deposits of gas hydrates. This paper presented isotopic and mineralogical analyses of authigenic carbonates from gas hydrate seepage structures in the Derugin Basin. Carbonate samples were taken from 20 sites located in 17 seepage structures in the basin. The mineralogy and isotope geochemistry of the authigenic carbonates were then compared in order to illustrate the processes associated with gas seepage to the seafloor, and to characterize the precipitation of authigenic carbonates at different seeps. Samples were analyzed using X-ray diffraction analyses. Results of the study demonstrated the existence of 4 different morphological types of carbonates comprised mainly of magnesium (Mg) calcite. Carbonates were poorly consolidated and fragile during the initial stage of carbonate concretion formation. In later stages, the carbonates became denser with a dendritic, or elongated shape, or rounded with subangular dense concretions. The final type was a tubicolous carbonate formed by the substitution of Polychaeta worms or burrows. The carbonates were light due to the presence of carbon from microbial methane. A mathematical model of the carbon-enriched samples was used to characterize carbonate precipitation caused by methanogenesis. A comparison between the model and samples obtained during field tests showed that the calculated equilibrium of the carbonates corresponded with the measured values. It was concluded that the basic mechanism of carbonate formation within the seepage structures was anaerobic methane oxidation via sulfate reduction. 22 refs., 2 figs.

  5. Gas seepage from Tokamachi mud volcanoes, onshore Niigata Basin (Japan): Origin, post-genetic alterations and CH{sub 4}-CO{sub 2} fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Etiope, G., E-mail: etiope@ingv.it [Istituto Nazionale di Geofisica e Vulcanologia, via V. Murata 605, 00143 Roma (Italy); Nakada, R. [Dept. of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University (Japan); Tanaka, K. [Graduate School of Science and Engineering, Yamaguchi University (Japan); Yoshida, N. [Dept. of Environmental Chemistry and Engineering, Tokyo Institute of Technology (Japan)

    2011-03-15

    Research highlights: {yields} Tokamachi gas shows signals of subsurface hydrocarbon biodegradation. {yields} Hydrocarbon molecular fractionation depends on gas flux. {yields} Substantial gas emission from mud volcanoes is from invisible diffuse seepage. {yields} Global mud volcano methane emission is likely higher than 10 Mt a{sup -1}. - Abstract: Methane and CO{sub 2} emissions from the two most active mud volcanoes in central Japan, Murono and Kamou (Tokamachi City, Niigata Basin), were measured in from both craters or vents (macro-seepage) and invisible exhalation from the soil (mini- and microseepage). Molecular and isotopic compositions of the released gases were also determined. Gas is thermogenic ({delta}{sup 13}C{sub CH4} from -32.9 per mille to -36.2 per mille), likely associated with oil, and enrichments of {sup 13}C in CO{sub 2} ({delta}{sup 13}C{sub CO2} up to +28.3 per mille) and propane ({delta}{sup 13}C{sub C3H8} up to -8.6 per mille) suggest subsurface petroleum biodegradation. Gas source and post-genetic alteration processes did not change from 2004 to 2010. Methane flux ranged within the orders of magnitude of 10{sup 1}-10{sup 4} g m{sup -2} d{sup -1} in macro-seeps, and up to 446 g m{sup -2} d{sup -1} from diffuse seepage. Positive CH{sub 4} fluxes from dry soil were widespread throughout the investigated areas. Total CH{sub 4} emission from Murono and Kamou were estimated to be at least 20 and 3.7 ton a{sup -1}, respectively, of which more than half was from invisible seepage surrounding the mud volcano vents. At the macro-seeps, CO{sub 2} fluxes were directly proportional to CH{sub 4} fluxes, and the volumetric ratios between CH{sub 4} flux and CO{sub 2} flux were similar to the compositional CH{sub 4}/CO{sub 2} volume ratio. Macro-seep flux data, in addition to those of other 13 mud volcanoes, supported the hypothesis that molecular fractionation (increase of the 'Bernard ratio' C{sub 1}/(C{sub 2} + C{sub 3})) is inversely

  6. The geochemistry characteristic and dating of cold seepage carbonates of the Pearl River Mouth Basin, eastern of South China Sea

    Science.gov (United States)

    Fang, Yunxin; Fu, Shaoying

    2015-04-01

    Cold seepage carbonates are usually formed by the interaction of methane oxidizing archaea, sulfate reducing bacteria and cold seepage which contain abundant venting hydrocarbon gases. The presence of cold seepage carbonates on the seabed is one of the evidences that the area exist venting hydrocarbon gases, which are usually result by the dissociation of gas hydrate. The cold seepage property and fluid flow rate can influence the oxidation-deoxidation environment of the bottom water and sediment. Many previous studies focused on the mineral composition, microstructure, elemental composition, isotope composition of the cold seepage carbonates and isotopic dating for the cold seepage carbonates. The isotopic dating for the cold seepage carbonates can provide the information of the gas hydrate formation and dissociation in some area of the South China Sea. High precision TIMS-U dating and 14C dating are used as routine method for the dating of the Quaternary carbonates and fossils. The cold seepage carbonates in the study include the samples collected by ROV on the seabed and the drilling for gas hydrate in the Pearl River Mouth Basin, eastern of the South China Sea. The authigenic carbonate occurred in different depth in the A, B and C drilling site. They may be represent different events of gas hydrate formation and dissociation in the Quaternary. The dating study for all the cold seepage carbonates can provide the relative accurate eras of the gas hydrate dissociation events in certain area of the South China Sea.

  7. Hydrocarbon Degradation in Caspian Sea Sediment Cores Subjected to Simulated Petroleum Seepage in a Newly Designed Sediment-Oil-Flow-Through System

    Directory of Open Access Journals (Sweden)

    Tina Treude

    2017-04-01

    Full Text Available The microbial community response to petroleum seepage was investigated in a whole round sediment core (16 cm length collected nearby natural hydrocarbon seepage structures in the Caspian Sea, using a newly developed Sediment-Oil-Flow-Through (SOFT system. Distinct redox zones established and migrated vertically in the core during the 190 days-long simulated petroleum seepage. Methanogenic petroleum degradation was indicated by an increase in methane concentration from 8 μM in an untreated core compared to 2300 μM in the lower sulfate-free zone of the SOFT core at the end of the experiment, accompanied by a respective decrease in the δ13C signal of methane from -33.7 to -49.5‰. The involvement of methanogens in petroleum degradation was further confirmed by methane production in enrichment cultures from SOFT sediment after the addition of hexadecane, methylnapthalene, toluene, and ethylbenzene. Petroleum degradation coupled to sulfate reduction was indicated by the increase of integrated sulfate reduction rates from 2.8 SO42-m-2 day-1 in untreated cores to 5.7 mmol SO42-m-2 day-1 in the SOFT core at the end of the experiment, accompanied by a respective accumulation of sulfide from 30 to 447 μM. Volatile hydrocarbons (C2–C6 n-alkanes passed through the methanogenic zone mostly unchanged and were depleted within the sulfate-reducing zone. The amount of heavier n-alkanes (C10–C38 decreased step-wise toward the top of the sediment core and a preferential degradation of shorter (C30 was seen during the seepage. This study illustrates, to the best of our knowledge, for the first time the development of methanogenic petroleum degradation and the succession of benthic microbial processes during petroleum passage in a whole round sediment core.

  8. Seepage laws of two kinds of disastrous gas in complete stress-strain process of coal

    Institute of Scientific and Technical Information of China (English)

    Cao Shugang; Guo Ping; Zhang Zunguo; Li Yi; Wang Yong

    2011-01-01

    The similarities and differences in seepage flow evolution laws of CH4 and CO2 during complete stressstrain process of samples were comparatively analyzed.The results show that the seepage flow evolution laws of CH4 and CO2 are extremely similar during the stress-strain process,showing that the characteristic first decreased and then increased.A mathematical model was also established according to the relationship of seepage velocity and axial strain.However,due to the strong adsorption ability of CO2,the coal samples generated a more serious “Klinkenberg effect” under the condition of CO2.Owing to this,the CO2 seepage flow resulted into occurrence of “stagnation” phenomenon during the late linear elastic stage Ⅱ.In the strain consolidation stage Ⅲ,the increment rate of CH4 seepage velocity was significantly greater than that of CO2.In the stress descent stage Ⅳ,when the axial load reached the peak pressure of coal,the increment rates of CH4 seepage velocity presented a turning point.But the changing rate of CO2 seepage velocity still remained slow and a turning point was presented at one time after the peak of the strain pressure,which showed an obvious feature of hysteresis.

  9. SLIPPAGE SOLUTION OF GAS PRESSURE DISTRIBUTION IN PROCESS OF LANDFILL GAS SEEPAGE

    Institute of Scientific and Technical Information of China (English)

    XUE Qiang; FENG Xia-ting; LIANG Bing

    2005-01-01

    A mathematical model of landfill gas migration was established under presumption of the effect of gas slippage. The slippage solutions to the nonlinear mathematical model were accomplished by the perturbation and integral transformation method. The distribution law of gas pressure in landfill site was presented under the conditions of considering and neglecting slippage effect. Sensitivity of the model input parameters was analyzed. The model solutions were compared to observation values.Results show that gas slippage effect has a large impact on gas pressure distribution.Landfill gas pressure and pressure gradient considering slippage effect is lower than that neglecting slippage effect, with reasonable agreement between model solution and measured data. It makes clear that the difference between considering and neglecting slippage effect is obvious and the effects of coupling cannot be ignored. The theoretical basis is provided for engineering design of security control and decision making of gas exploitation in landfill site. The solutions give scientific foundation to analyzing well test data in the process of low-permeability oil gas reservoir exploitation.

  10. National Gas Survey. Synthesized gaseous hydrocarbon fuels

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    The supply-Technical Advisory Task Force-Synthesized Gaseous Hydrocarbon Fuels considered coal, hydrocarbon liquids, oil shales, tar sands, and bioconvertible materials as potential feedstocks for gaseous fuels. Current status of process technology for each feedstock was reviewed, economic evaluations including sensitivity analysis were made, and constraints for establishment of a synthesized gaseous hydrocarbon fuels industry considered. Process technology is presently available to manufacture gaseous hydrocarbon fuels from each of the feedstocks. In 1975 there were eleven liquid feedstock SNG plants in the United States having a capacity of 1.1 billion SCFD. There can be no contribution of SNG before 1982 from plants using feedstocks other than liquids because there are no plants in operation or under construction as of 1977. Costs for SNG are higher than current regulated prices for U.S. natural gas. Because of large reserves, coal is a prime feedstock candidate although there are major constraints in the area of coal leases, mining and water permits, and others. Commercial technology is available and several new gasification processes are under development. Oil shale is also a feedstock in large supply and commercial process technology is available. There are siting and permit constraints, and water availability may limit the ultimate size of an oil shale processing industry. Under projected conditions, bioconvertible materials are not expected to support the production of large quantities of pipeline quality gas during the next decade. Production of low or medium Btu gas from municipal solid wastes can be expected to be developed in urban areas in conjunction with savings in disposal costs. In the economic evaluations presented, the most significant factor for liquid feedstock plants is the anticipated cost of feedstock and fuel. The economic viability of plants using other feedstocks is primarily dependent upon capital requirements.

  11. Hydrocarbon and Carbon Dioxide Fluxes from Natural Gas Well Pad Soils and Surrounding Soils in Eastern Utah.

    Science.gov (United States)

    Lyman, Seth N; Watkins, Cody; Jones, Colleen; Mansfield, Marc L; McKinley, Michael; Kenney, Donna; Evans, Jordan

    2017-09-07

    We measured fluxes of methane, non-methane hydrocarbons, and carbon dioxide from natural gas well pad soils and from nearby undisturbed soils in eastern Utah. Methane fluxes varied from less than zero to more than 38 g m-2 h-1. Fluxes from well pad soils were almost always greater than from undisturbed soils. Fluxes were greater from locations with higher concentrations of total combustible gas in soil and were inversely correlated with distance from well heads. Several lines of evidence show that the majority of emission fluxes (about 70%) were primarily due to subsurface sources of raw gas that migrated to the atmosphere, with the remainder likely caused primarily by re-emission of spilled liquid hydrocarbons. Total hydrocarbon fluxes during summer were only 39 (16, 97)% as high as during winter, likely because soil bacteria consumed the majority of hydrocarbons during summer months. We estimate that natural gas well pad soils account for 4.6×10-4 (1.6×10-4, 1.6×10-3)% of total emissions of hydrocarbons from the oil and gas industry in Utah's Uinta Basin. Our undisturbed soil flux measurements were not adequate to quantify rates of natural hydrocarbon seepage in the Uinta Basin.

  12. Geochemical characteristics and origin of light hydrocarbons in biogenic gas

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The light hydrocarbon geochemical characteristics of biogenic gases from Sebei 1 gas field in the Qaidam Basin, Baoshan gas field in the Baoshan Basin and Alaxin gas field, Puqian gas pool, Aonan gas pool in the Songliao Basin are studied and the origin is discussed based on the composition and isotope data of gases. The isoalkane contents among light hydrocarbons in natural gas show a negative relationship with δ13C1 values. The isoalkane contents of the gases with δ13C1 values of less than ?60‰ are also high with more than 40% among light hydrocarbons in Sebei 1 gas field and Puqian gas pool. Moreover, the 2,2-dimethylbutane and 2-methylpentane, mainly sourced from bacteria, have predominance among isoalkanes, which suggests that light hydrocarbons in biogenic gases from these gas fields or pools were probably generated by microbial action. However, the cycloalkane contents among light hydrocarbons in biogenic gas are related to δ13C1 values positively. In Alaxin gas field and Aonan gas pool, where δ13C1 values of biogenic gases are less than ?60‰, the average contents of cycloalkane are higher than 44%. Light hydrocarbons among biogenic gases from these gas fields were probably generated by catalysis. The isoalkane and cycloalkane contents among light hydrocarbons from biogenic gases in the Baoshan gas field are both high, which might be generated by these two actions. The results show that the data of light hydrocarbons in biogenic gas can provide important information for understanding the generation mechanisms of light hydrocarbons during geological evolution and identifying biogenic gas and low mature gas.

  13. Recovery of nitrogen and light hydrocarbons from polyalkene purge gas

    Science.gov (United States)

    Zwilling, Daniel Patrick; Golden, Timothy Christoph; Weist, Jr., Edward Landis; Ludwig, Keith Alan

    2003-06-10

    A method for the separation of a gas mixture comprises (a) obtaining a feed gas mixture comprising nitrogen and at least one hydrocarbon having two to six carbon atoms; (b) introducing the feed gas mixture at a temperature of about 60.degree. F. to about 105.degree. F. into an adsorbent bed containing adsorbent material which selectively adsorbs the hydrocarbon, and withdrawing from the adsorbent bed an effluent gas enriched in nitrogen; (c) discontinuing the flow of the feed gas mixture into the adsorbent bed and depressurizing the adsorbent bed by withdrawing depressurization gas therefrom; (d) purging the adsorbent bed by introducing a purge gas into the bed and withdrawing therefrom an effluent gas comprising the hydrocarbon, wherein the purge gas contains nitrogen at a concentration higher than that of the nitrogen in the feed gas mixture; (e) pressurizing the adsorbent bed by introducing pressurization gas into the bed; and (f) repeating (b) through (e) in a cyclic manner.

  14. Hydrocarbon radical thermochemistry: Gas-phase ion chemistry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ervin, Kent M. [Univ. of Nevada, Reno, NV (United States)

    2014-03-21

    Final Scientific/Technical Report for the project "Hydrocarbon Radical Thermochemistry: Gas-Phase Ion Chemistry Techniques." The objective of this project is to exploit gas-phase ion chemistry techniques for determination of thermochemical values for neutral hydrocarbon radicals of importance in combustion kinetics.

  15. Gas-phase infrared photodissociation spectroscopy of cationic polyaromatic hydrocarbons

    NARCIS (Netherlands)

    Oomens, J.; van Roij, A. J. A.; Meijer, G.; von Helden, G.

    2000-01-01

    Infrared spectra of gas-phase cationic naphthalene, phenanthrene, anthracene, and pyrene are recorded in the 500-1600 cm(-1) range using multiphoton dissociation in an ion trap. Gas-phase polyaromatic hydrocarbons are photoionized by an excimer laser and stored in a quadrupole ion trap. Subsequent i

  16. Gas seepage on the sea floor of Okinawa Trough Miyako Section

    Institute of Scientific and Technical Information of China (English)

    LUAN Xiwu; QIN Yunshan

    2005-01-01

    A marine geophysical survey was carried out, on the R/V Science 1 of the Institute of Oceanography, Chinese Academy of Sciences (IOCAS), in 2000, at the Miyako Section of Okinawa Trough. Here we present seismic and acoustic evidence of a gas seep on the sea floor on the western part of the Okinawa Trough, near the lower slope of the East China Sea Slope and discuss the possibility of related formation of gas hydrate. A gas column reflection was observed in echo-sounder data above a section where the sea floor reflector was missing, on both the echo-sounder and the seismic data for line H14. The seismic data also show an acoustic curtain reflection and a turbidity reflection at this section. These anomalies are the evidence of the existence of a gas seep, which occupies an area 2.2 km in diameter. Based on the acoustic curtain on line H14, we believe that the amount of gas contained in the sediments below the gas seep is larger than 1% by volume of sediment. Tectonically, the gas seep developed in a small basin controlled by basement uplift in the north, south and east. The thickness of the sediment layer can be greater than 3.5 km. A mud diapir structure was found in layer D beneath the gas seep. Over-pressure may occur due to the large sediment thickness and also the tectonic basement uplift in the north, south, and east. The mud diapir could be the preferential pathway for methane-rich fluids. The acoustic curtain may indicate that free gas related to the gas seep can be formed on the sea floor. We also note that the layer above the acoustic curtain on profile H14 may contain gas hydrate.

  17. Seepage from an arctic shallow marine gas hydrate reservoir is insensitive to momentary ocean warming

    Science.gov (United States)

    Hong, Wei-Li; Torres, Marta E.; Carroll, Jolynn; Crémière, Antoine; Panieri, Giuliana; Yao, Haoyi; Serov, Pavel

    2017-06-01

    Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ~380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.

  18. Historical and geochemical outlines of the oil-gas seepage near Turzovka town; Flysch belt, NW Slovakia

    Directory of Open Access Journals (Sweden)

    Juraj Macek

    2012-06-01

    Full Text Available Small oil deposits located in Korňa near the town of Turzovka in north-western Slovakia and other small deposits located in the Miková region of northern-eastern Slovakia were the first oil deposits discovered and exploited in these parts of the Western Carpathians. Small volumes of oil, natural gas and water rises to the surface on a northern slope in Korňa and several tenths of metres further on these descends into the soil cover and entered the local Kornianka creek. Korňa and its broader surrounds are geologically part of the Magura Nappe of the Carpathian Flysch Belt. The preliminary gas chromatography results indicate weakly biodegraded mature oil with a prevailing aliphatic hydrocarbon fraction. Weak biodegradation and continuous outflow over 100 years following its discovery in 1901 indicate its connection with a deeper oil reservoir. Although methane is the dominant component of this natural gas, the presence of higher gaseous hydrocarbons with the methane carbon isotopic composition indicates a methane gas associated with the main stage of oil generation.

  19. Seepage flow behaviors of multi-stage fractured horizontal wells in arbitrary shaped shale gas reservoirs

    Science.gov (United States)

    Zhao, Yu-Long; Shan, Bao-Chao; Zhang, Lie-Hui; Liu, Qi-Guo

    2016-10-01

    The horizontal well incorporated with massive hydraulic fracturing has become a key and necessary technology to develop shale gas reservoirs efficiently, and transient pressure analysis is a practical method to evaluate the effectiveness of the fracturing. Until now, however, the related studies on the pressure of such wells have mainly focused on regular outer-boundaries, such as infinite, circular and rectangular boundary shapes, which do not always fulfill the practical conditions and, of course, could cause errors. By extending the boundary element method (BEM) into the application of multi-staged fractured horizontal wells, this paper presents a way of analyzing the transient pressure in arbitrary shaped shale gas reservoirs considering ad-/de-sorption and diffusion of the shale gas with the ‘tri-porosity’ mechanism model. The boundary integral equation can be obtained by coupling the fundamental solution of the Helmholtz equation with the dimensionless diffusivity equation. After discretizing the outer-boundaries and the fractures, the boundary integral equations are linearized and the coefficient matrix of the pressure on the boundaries is assembled, after which bottom-hole pressure can be calculated conveniently. Comparing the BEM solution with semi-analytical solution cases, the accuracy of the new solution can be validated. Then, the characteristic curves of the dimensionless pseudo pressure, as well as its derivative for a well in shale gas reservoirs, are drawn, based on which the parameters’ sensitivity analyses are also conducted. This paper not only enriches the well testing theory and method in shale gas reservoirs, but also provides an effective method to solve problems with complex inner- and outer-boundaries.

  20. Direct hydrocarbon exploration and gas reservoir development technology

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Young Hoon; Oh, Jae Ho; Jeong, Tae Jin [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)] [and others

    1995-12-01

    In order to enhance the capability of petroleum exploration and development techniques, three year project (1994 - 1997) was initiated on the research of direct hydrocarbon exploration and gas reservoir development. This project consists of four sub-projects. (1) Oil(Gas) - source rock correlation technique: The overview of bio-marker parameters which are applicable to hydrocarbon exploration has been illustrated. Experimental analysis of saturated hydrocarbon and bio-markers of the Pohang E and F core samples has been carried out. (2) Study on surface geochemistry and microbiology for hydrocarbon exploration: the test results of the experimental device for extraction of dissolved gases from water show that the device can be utilized for the gas geochemistry of water. (3) Development of gas and gas condensate reservoirs: There are two types of reservoir characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. (4) Numerical modeling of seismic wave propagation and full waveform inversion: Three individual sections are presented. The first one is devoted to the inversion theory in general sense. The second and the third sections deal with the frequency domain pseudo waveform inversion of seismic reflection data and refraction data respectively. (author). 180 refs., 91 figs., 60 tabs.

  1. Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

    Science.gov (United States)

    Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

    2015-12-01

    Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

  2. Water and gas seepage at the Salton Sea Geothermal System (California, USA)

    Science.gov (United States)

    Mazzini, A.; Svensen, H.; Polteau, S.; Planke, S.

    2009-04-01

    The Davis-Schrimpf seep field (Salton Sea, California) represents an ideal site for investigating the activity of hydrothermal systems. At this site, dozens of seeps (gryphons-pools) constantly expel water, mud, gas, and petroleum-fluids. We have conducted a long term monitoring on water and gas geochemistry of fluids erupted as well as annual temperature records. The fluids geochemistry and the temperature vary significantly at closely spaced locations and the water content present in the seeps acts as a key factor. The water salinity varies between fresh (1-3 g/L) in the gryphons, to hypersaline brine (145 g/L) in the pools. The gas emitted by the main vents revealed a composition averagely dominated by C02 (up to 99%) with smaller contributions of CH4. The seep waters represent meteoric waters modified by surface evaporation, with little or no evidence for a deep hydrothermal component. Seep gases, on the other hand, have a deep metamorphic/mantle origin. Temperature monitoring shows that gryphons are dominated by hydrothermal input and the pools by diurnal variations in air temperature. More recently we have conducted a broad investigation of the flux of CO2 and CH4 on a 20x20m meters grid covering a surface of over 20,000 square meters. The survey area extends over the main focussed vents and the results show that a considerable amount of CO2 and is constantly seeping through microseepage. Locally CH4 also exhibits areas with strong microseepage mainly where higher temperatures and surface minerals precipitations occur. These data reveal how important is the effect of microseepage when calculating global budgets of CO2 emissions in hydrothermal fields.

  3. Carbonate Chemistry Dynamics in an Area of Active Gas Seepage: the Hudson Canyon, US Atlantic Margin

    Science.gov (United States)

    Garcia-Tigreros Kodovska, F.; Kessler, J. D.; Leonte, M.; Chepigin, A.; Kellermann, M. Y.; Arrington, E. C.; Valentine, D. L.

    2015-12-01

    The fate of oceanic methane and its impact on the global climate has been of particular interest to the global community. The potential for vast amounts of methane to be emitted from the seafloor into the atmosphere due to gas hydrate decomposition has been under scientific evaluation. However, despite the great extent of these geological reservoirs, much of the methane released from the seafloor in deep ocean environments does not reach the atmosphere. Once dissolved in ocean water, the emitted methane can be microbially converted to either carbon dioxide or assimilated to biomass. Here, we will present results from a research cruise to the Hudson Canyon, northern US Atlantic Margin, where we investigated changes in ocean water carbonate chemistry induced by the oxidation of methane released from gas seeps. We will be presenting high precision pH data as well as methane and DIC concentrations, natural stable isotopes, and methane oxidation rates collected inside and adjacent to the Hudson Canyon in the summer of 2014.

  4. Computational Fluid Dynamics Simulation of Oxygen Seepage in Coal Mine Goaf with Gas Drainage

    Directory of Open Access Journals (Sweden)

    Guo-Qing Shi

    2015-01-01

    Full Text Available Mine fires mainly arise from spontaneous combustion of coal seams and are a global issue that has attracted increasing public attention. Particularly in china, the closure of coal workfaces because of spontaneous combustion has contributed to substantial economic loss. To reduce the occurrence of mine fires, the spontaneous coal combustion underground needs to be studied. In this paper, a computational fluid dynamics (CFD model was developed for coal spontaneous combustion under goaf gas drainage conditions. The CFD model was used to simulate the distribution of oxygen in the goaf at the workface in a fully mechanized cave mine. The goaf was treated as an anisotropic medium, and the effects of methane drainage and oxygen consumption on spontaneous combustion were considered. The simulation results matched observational data from a field study, which indicates CFD simulation is suitable for research on the distribution of oxygen in coalmines. The results also indicated that near the workface spontaneous combustion was more likely to take place in the upper part of the goaf than near the bottom, while further from workface the risk of spontaneous combustion was greater in the lower part of the goaf. These results can be used to develop firefighting approaches for coalmines.

  5. Hydrocarbon Specificity During Aerobic oil Biodegradation Revealed in Marine Microcosms With the use of Comprehensive, Two-Dimensional Gas Chromatography.

    Science.gov (United States)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Valentine, D. L.

    2008-12-01

    In 2003 the National Research Council reported more than 380 million gallons of oil is emitted into the ocean each year from natural seepage and as a result of anthropogenic activities. Many of the hydrocarbons making up this oil are persistent and toxic to marine life. Petroleum emitted into biologically sensitive areas can lead to environmental stress and ecosystem collapse. As a result many studies and a substantial amount of resources have been devoted to creating efficient and effective remediation tools and developing a better understanding of natural hydrocarbon weathering processes occurring in marine environments. The goal of this study is to elucidate patterns and extent of aerobic hydrocarbon degradation in marine sediments. In order to assess the specific molecular transformations occurring in petroleum emitted into oxic marine environments, we prepared microcosm experiments using sediments and seawater collected from the natural oil seeps offshore Coal Oil Point, California. Petroleum recovered from Platform Holly in the Santa Barbara Channel, was added to a sediment-seawater mixture and the microcosm bottles were allowed to incubate under aerobic conditions for slightly more than 100 days. Comprehensive, two-dimensional gas chromatography was employed in this study to quantify changes in the concentrations of individual hydrocarbon compounds because of the increased resolution and resolving power provided with this robust analytical method. We show significant hydrocarbon mass loss due to aerobic biodegradation for hundreds of tracked compounds in the microcosm bottles. The results shown here provide quantitative evidence for broad-scale metabolic specificity during aerobic hydrocarbon degradation in surface and shallow subsurface marine sediments.

  6. Passive acoustic derived bubble flux and applications to natural gas seepage in the Mackenzie Delta, NWT, Canada and Coal Oil Point, CA

    Science.gov (United States)

    Culling, D.; Leifer, I.; Dallimore, S.; Alcala, K.

    2012-12-01

    Methane is a prominent greenhouse gas that escapes naturally from thermogenic reservoirs as seepage from marine and lacustrine biogenic sources as bubble ebullition. Geologic methane emissions are critically important contributors to the global methane budget however, few quantitative flux measurements are available for shallow waters. This gap in knowledge is critical as in these settings gas can easily transit as bubbles through the water column and directly influence global atmospheric budgets. Video and active acoustic (sonar) measurements of bubble flux have spatial limitations requiring predictable bubble emission location. Passive acoustics are less affected by these limitations, in addition, they can provide data in water too shallow for effective sonar bubble observations. Lab tests were undertaken to quantify the acoustic signature of bubbles formed in non-cohesive sediments. specifically focusing on mechanisms that complicate interpretation of acoustic data. Lab tests then were compared to field data to provide measurement calibration/validation. The principles behind the acoustic analysis method are based on the Minnaert equation, which relates a bubble radius and acoustic frequency. Bubble size and the resultant acoustic frequency from known flows and capillary tube diameters are well documented; however changing sediment pathways adds to the complexity of bubble formation and the resultant bubble acoustic signal. These complex signals were investigated in a lab tank with a thick, cohesive fine-grained sediment bed, through which bubbles produced by a syringe pump migrated to the sediment-water interface. Then, the resultant bubbles were diverted into clear water and measured from high speed, high definition video, while the acoustic signature of bubble formation was recorded concurrently by a hydrophone. Bubble formation is influenced by currents, which shifts the acoustical signal towards a higher frequency with a more complex pattern than the

  7. Calculation of hydrocarbon-in-place in gas and gas-condensate reservoirs - Carbon dioxide sequestration

    Science.gov (United States)

    Verma, Mahendra K.

    2012-01-01

    The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2), requiring estimation of hydrocarbon-in-place volumes and formation volume factors for all the oil, gas, and gas-condensate reservoirs within the U.S. sedimentary basins. The procedures to calculate in-place volumes for oil and gas reservoirs have already been presented by Verma and Bird (2005) to help with the USGS assessment of the undiscovered resources in the National Petroleum Reserve, Alaska, but there is no straightforward procedure available for calculating in-place volumes for gas-condensate reservoirs for the carbon sequestration project. The objective of the present study is to propose a simple procedure for calculating the hydrocarbon-in-place volume of a condensate reservoir to help estimate the hydrocarbon pore volume for potential CO2 sequestration.

  8. H-Area Seepage Basins

    Energy Technology Data Exchange (ETDEWEB)

    Stejskal, G.

    1990-12-01

    During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

  9. Seepage Calibration Model and Seepage Testing Data

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-02-17

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM is developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA (see upcoming REV 02 of CRWMS M&O 2000 [153314]), which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model (see BSC 2003 [161530]). The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross Drift to obtain the permeability structure for the seepage model; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty of

  10. Oil seepage detection technique as a tool to hydrocarbon prospecting in offshore Campos Basin-Brazil; Deteccao de exsudacoes de oleo como uma ferramenta de prospeccao de hidrocarbonetos na regiao maritima da Bacia de Campos - Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Castilho, Jose G.; Brito, Ademilson F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Modelagem de Bacias (LAB2M); Landau, Luiz [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Metodos Computacionais em Engenharia (LAMCE)

    2004-07-01

    With a proven capacity to identify oil slicks in offshore regions, RADARSAT-1 imagery can be useful for oil exploration purposes. The paper discusses the seepage detection method at Campos Basin, offshore Rio de Janeiro State, which is responsible for 80% of the Brazilian production of oil and gas. It is known that the horizontal migration of petroleum can occurs over tens or even hundreds of kilometers, where the source rock placed in more deep locations can be linked with shallow reservoirs or traps and even reach the ocean. It means that seepage can provide information for risking petroleum charge at basin scales, and cannot have a direct relation with the geographical position of the interpreted seeps and possible filled prospects. A good understanding of the geology, and hence the petroleum systems of a basin is the key to use seepage in exploration. The work is divided into three main steps. First step were select oil seepages interpreted at Campos Basin where is found several giant petroleum fields. Second, the geology of the study area and its structural and stratigraphic features were analyzed, in order to identify possible migration pathways related to faults generated by halokinesis. Another important aspect is the presence of 'windows' or ducts in the evaporates beds allowing the contact between the section that contains source rocks and the turbidities reservoirs, that contain the majority of the oil discovers. All these features were interpreted based on a regional dip seismic line (203 - 76), and a geologic cross section with E-W orientation, showing the structure of the Marlim Field. Finally, all the information was integrated in a Geographical Information System (GIS), and then analyzed in an interdisciplinary environment, with the intention to link possible routes of oil migration to post-evaporites reservoirs or to interpreted seeps. (author)

  11. Fault zone controlled seafloor methane seepage in the rupture area of the 2010 Maule earthquake, Central Chile

    Science.gov (United States)

    Geersen, Jacob; Scholz, Florian; Linke, Peter; Schmidt, Mark; Lange, Dietrich; Behrmann, Jan H.; Völker, David; Hensen, Christian

    2016-11-01

    Seafloor seepage of hydrocarbon-bearing fluids has been identified in a number of marine fore arcs. However, temporal variations in seep activity and the structural and tectonic parameters that control the seepage often remain poorly constrained. Subduction zone earthquakes, for example, are often discussed to trigger seafloor seepage but causal links that go beyond theoretical considerations have not yet been fully established. This is mainly due to the inaccessibility of offshore epicentral areas, the infrequent occurrence of large earthquakes, and challenges associated with offshore monitoring of seepage over large areas and sufficient time periods. Here we report visual, geochemical, geophysical, and modeling results and observations from the Concepción Methane Seep Area (offshore Central Chile) located in the rupture area of the 2010 Mw. 8.8 Maule earthquake. High methane concentrations in the oceanic water column and a shallow subbottom depth of sulfate penetration indicate active methane seepage. The stable carbon isotope signature of the methane and hydrocarbon composition of the released gas indicate a mixture of shallow-sourced biogenic gas and a deeper sourced thermogenic component. Pristine fissures and fractures observed at the seafloor together with seismically imaged large faults in the marine fore arc may represent effective pathways for methane migration. Upper plate fault activity with hydraulic fracturing and dilation is in line with increased normal Coulomb stress during large plate-boundary earthquakes, as exemplarily modeled for the 2010 earthquake. On a global perspective our results point out the possible role of recurring large subduction zone earthquakes in driving hydrocarbon seepage from marine fore arcs over long timescales.

  12. Interaction between hydrocarbon seepage, chemosynthetic communities, and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

    Directory of Open Access Journals (Sweden)

    D. Fischer

    2012-06-01

    Full Text Available The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ located at the Makran convergent continental margin. Push cores were obtained from seeps within and below the core-OMZ with a remotely operated vehicle. Extracted sediment pore water was analyzed for sulfide and sulfate concentrations. Depending on oxygen availability in the bottom water, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats, which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was retained within the sediment.

    Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr−1 to <1 cm yr−1 and the sulfate/methane transition (SMT deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMT did not significantly differ (6.6–9.3 mol m−2 yr−1. Depth-integrated rates of bioirrigation increased from 120 cm yr−1 in the central habitat, characterized by microbial mats and sparse macrofauna, to 297 cm yr−1 in the habitat of large and few small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats below the core-OMZ efficiently bioirrigate and thus transport sulfate down into the upper 10 to 15 cm of the sediment. In this way the animals deal with the lower upward flux of methane in outer habitats by stimulating rates of anaerobic oxidation of methane (AOM with sulfate high enough to provide

  13. Seepage Calibration Model and Seepage Testing Data

    Energy Technology Data Exchange (ETDEWEB)

    S. Finsterle

    2004-09-02

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM was developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). This Model Report has been revised in response to a comprehensive, regulatory-focused evaluation performed by the Regulatory Integration Team [''Technical Work Plan for: Regulatory Integration Evaluation of Analysis and Model Reports Supporting the TSPA-LA'' (BSC 2004 [DIRS 169653])]. The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross-Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA [''Seepage Model for PA Including Drift Collapse'' (BSC 2004 [DIRS 167652])], which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model [see ''Drift-Scale Coupled Processes (DST and TH Seepage) Models'' (BSC 2004 [DIRS 170338])]. The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross-Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross

  14. Sources, extent and history of methane seepage on the continental shelf off northern Norway

    Science.gov (United States)

    Sauer, Simone; Lepland, Aivo; Chand, Shyam; Schubert, Carsten J.; Eichinger, Florian; Knies, Jochen

    2014-05-01

    Active natural hydrocarbon gas seepage was recently discovered in the Hola area on the continental shelf off Vesterålen, northern Norway. We conducted acoustic and geochemical investigations to assess the modern and past extent, source and pathways of the gas seepage . Water column echosounder surveys showed bubble plumes up to several tens of metres above the seafloor. Analyses of dissolved methane in the water column indicated slightly elevated concentrations (50 nM) close to the seafloor. To identify fluxes and origin of methane in the sediments we analysed sediment pore water chemistry, the isotopic composition of methane and of dissolved inorganic carbon (d13CCH4, d2HCH4, d13CDIC) in three closely spaced (

  15. Hydrocarbon gas detection with microelectromechanical Fabry-Perot interferometer

    Science.gov (United States)

    Mannila, Rami; Tuohiniemi, Mikko; Mäkynen, Jussi; Näkki, Ismo; Antila, Jarkko

    2013-05-01

    VTT Technical Research Centre of Finland has developed microelectromechanical (MEMS) Fabry-Perot interferometer (FPI) for hydrocarbon measurements. Fabry-Perot interferometer is a structure where is two highly reflective surfaces separated by a tunable air gap. The MEMS FPI is a monolithic device, i.e. it is made entirely on one substrate in a batch process, without assembling separate pieces together. The gap is adjusted by moving the upper mirror with electrostatic force, so there are no actual moving parts. The manufactured MEMS FPIs have been characterized. The tuning wavelength range of the MEMS FPI is 2.8-3.5 μm and its spectral resolution is 50-60 nm. VTT has designed and manufactured a handheld size demonstrator device based on the technology presented in this abstract. This device demonstrates gas detecting by measuring cigarette lighter gas and various plastic materials transmission spectra. The demonstrator contains light source, gas cell, MEMS FPI, detector and control electronics. It is connected to a laptop by USB connection, additional power supply or connection is not needed.

  16. Characterization of Preferential Ground-Water Seepage From a Chlorinated Hydrocarbon-Contaminated Aquifer to West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 2002-04

    Science.gov (United States)

    Majcher, Emily H.; Phelan, Daniel J.; Lorah, Michelle M.; McGinty, Angela L.

    2007-01-01

    Wetlands act as natural transition zones between ground water and surface water, characterized by the complex interdependency of hydrology, chemical and physical properties, and biotic effects. Although field and laboratory demonstrations have shown efficient natural attenuation processes in the non-seep wetland areas and stream bottom sediments of West Branch Canal Creek, chlorinated volatile organic compounds are present in a freshwater tidal creek at Aberdeen Proving Ground, Maryland. Volatile organic compound concentrations in surface water indicate that in some areas of the wetland, preferential flow paths or seeps allow transport of organic compounds from the contaminated sand aquifer to the overlying surface water without undergoing natural attenuation. From 2002 through 2004, the U.S. Geological Survey, in cooperation with the Environmental Conservation and Restoration Division of the U.S. Army Garrison, Aberdeen Proving Ground, characterized preferential ground-water seepage as part of an ongoing investigation of contaminant distribution and natural attenuation processes in wetlands at this site. Seep areas were discrete and spatially consistent during thermal infrared surveys in 2002, 2003, and 2004 throughout West Branch Canal Creek wetlands. In these seep areas, temperature measurements in shallow pore water and sediment more closely resembled those in ground water than those in nearby surface water. Generally, pore water in seep areas contaminated with chlorinated volatile organic compounds had lower methane and greater volatile organic compound concentrations than pore water in non-seep wetland sediments. The volatile organic compounds detected in shallow pore water in seeps were spatially similar to the dominant volatile organic compounds in the underlying Canal Creek aquifer, with both parent and anaerobic daughter compounds detected. Seep locations characterized as focused seeps contained the highest concentrations of chlorinated parent compounds

  17. Shale Hydrocarbon Prospecting in the Central Part of the Volga-Ural Oil and Gas Province

    Science.gov (United States)

    Muslimov, Renat Kh.; Plotnikova, Irina N.

    2014-05-01

    Until now nobody has prospected or estimated the oil shale resources in Tatarstan, although the high-carbon rocks of Domanikoidtype often became an object of studies dedicated to assessment of the generation potential of liquid and gaseous hydrocarbons. The evaluation of oil-shale deposits in Tatarstan should base on the well-known geological, geochemical and technological criteria. The main, determining conditions for shale oil and gas deposit formation are the following: high content of organic matter (OM) in the rock, and its certain catagenetic maturity; special features of the mineral composition of rocks that contribute to the formation of fractures; and the presence of overlying and underlying impermeable dense strata that ensure the safety of hydrocarbons in the shale series. In Tatarstan, the development prospects of shale oil fields should be associated primarily with the rocks ofDomanikoid formations of Upper Devonian - such as Semiluksky (Domanik) horizon, as well asRechitsky (Mendymsky) horizon and Domanikoid formations of central and side areas of the Kama-Kinel trough system. Studies on Domanikwere started in the middle of the last century, when the Ural-Volga region experienced active interest for oil exploration. Then the research of Domanikoid series was carried out at the Department of Oil and Gas Geology, Kazan State University. Butback then the prospecting was not clearly associated with an estimate of shale oil resources. As revealed during rock geochemical studies of the rock, the average content of organic matter in deposits of Semiluksky and Mendymsky horizons is 8.35 and 2.56 % respectively, which is enough to takethese horizons as the main object of research and resource assessment. The presence of silica rocks and dense limestone in such a large proportion is a favorable factor in terms of assessing the effectiveness of fracturing. So we have a quite clear understanding of how to explore Domanik. In fact, the geological structure of our

  18. Kinetics of hydrocarbon generation for Well Yingnan 2 gas reservoir,Tarim Basin,CHina

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Well Yingnan 2,an important exploratory well in the east of Tarim Basin,yields high commercial oil and gas flow in Jurassic.Natural gas components and carbon isotopic composition indicate that it belongs to sapropel type gas.Because this region presents many suits of hydrocarbon source rocks,there are some controversies that natural gases were generated from kerogen gas or crude oil cracking gas at present.By using the kinetics of hydrocarbon generation and carbon isotope,natural gas of Well Yingnan 2 is composed mainly of crude oil cracking gas,about 72%,it is generated from secondary kerogen gas of Cambrian-Lower Ordovician source rock and crude oil cracking gas of Mid-Upper Ordovician oil reservoir.The main oil and gas filling time is 65 Ma later in the Jurassic gas reservoir of Well Yingnan 2,so the gas reservoir belongs to late accumulation and continuous filling type.

  19. Abstraction of Drift Seepage

    Energy Technology Data Exchange (ETDEWEB)

    J.T. Birkholzer

    2004-11-01

    This model report documents the abstraction of drift seepage, conducted to provide seepage-relevant parameters and their probability distributions for use in Total System Performance Assessment for License Application (TSPA-LA). Drift seepage refers to the flow of liquid water into waste emplacement drifts. Water that seeps into drifts may contact waste packages and potentially mobilize radionuclides, and may result in advective transport of radionuclides through breached waste packages [''Risk Information to Support Prioritization of Performance Assessment Models'' (BSC 2003 [DIRS 168796], Section 3.3.2)]. The unsaturated rock layers overlying and hosting the repository form a natural barrier that reduces the amount of water entering emplacement drifts by natural subsurface processes. For example, drift seepage is limited by the capillary barrier forming at the drift crown, which decreases or even eliminates water flow from the unsaturated fractured rock into the drift. During the first few hundred years after waste emplacement, when above-boiling rock temperatures will develop as a result of heat generated by the decay of the radioactive waste, vaporization of percolation water is an additional factor limiting seepage. Estimating the effectiveness of these natural barrier capabilities and predicting the amount of seepage into drifts is an important aspect of assessing the performance of the repository. The TSPA-LA therefore includes a seepage component that calculates the amount of seepage into drifts [''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504], Section 6.3.3.1)]. The TSPA-LA calculation is performed with a probabilistic approach that accounts for the spatial and temporal variability and inherent uncertainty of seepage-relevant properties and processes. Results are used for subsequent TSPA-LA components that may handle, for example, waste package

  20. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    Science.gov (United States)

    Lahvis, Matthew A.; Baehr, Arthur L.

    1996-07-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 gyr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 gm-2yr-1 (1.45×10-3 and 1.51×10-3 gal.ft.-2yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  1. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    Science.gov (United States)

    Lahvis, M.A.; Baehr, A.L.

    1996-01-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 g yr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 g m-2 yr-1 (1.45 x 10-3 and 1.51 x 10-3 gal. ft.-2 yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  2. Methods for natural gas and heavy hydrocarbon co-conversion

    Science.gov (United States)

    Kong, Peter C.; Nelson, Lee O.; Detering, Brent A.

    2009-02-24

    A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

  3. Recovery Process for Lighter Hydrocarbon of Natural Gas in Liaohe Oilfield

    Institute of Scientific and Technical Information of China (English)

    Sun Fulu

    1995-01-01

    @@ Liaohe Oilfield, the third largest oilfield in China is richer in natural gas. Up to the end of 1993,the accumulative production of natural gas reached 31. 15 billion m3,among which associated gas occupied 19.83 billion m3. In the recent ten years ,more than ten of lighter hydrocarbon recovery units with different scales have been constructed. The following is describing the main process features about recovery units of 200 × 104m3/d,120× 104 m3/d and other small recovery units for lighter hydrocarbon of natural gas.

  4. Seepage Anisotropy of Heterogeneous Body

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ore dumps are heterogeneous bodies with anisotropic seepage characteristics because of the ore segregation.In an indoor experiment, a dump was constructed with three strata, where the horizontal and vertical seepage experiments were carried out.Horizontals flow are regarded as phreatic plan flows without penetration.Its seepage law satifies the Dupuit equation.With parallel lay seepage model, the equivalent seepage coefficient in the horizontal flow was obtained and was equivalent to the weighted mean of the seepage coefficient of each stratum.An unsaturated flow appeared in the vertical experiment, with a hydraulic gradient of 1.The vertical flow was equivalent to the seepage model that moved in vertical bedding; its equivalent seepage coefficient depended on the stratum with the minimum seepage coefficient.That the experiment showed clear anisotropy in a heterogeneous body was obvious with an anisotropic coefficient between 63 and 155, which is 25 to 100 times larger than that of a homogeneous body.

  5. Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

    NARCIS (Netherlands)

    Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

    2006-01-01

    A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

  6. Diesel-related hydrocarbons can dominate gas phase reactive carbon in megacities

    Directory of Open Access Journals (Sweden)

    R. E. Dunmore

    2015-09-01

    Full Text Available Hydrocarbons are key precursors to two priority air pollutants, ozone and particulate matter. Those with two to seven carbons have historically been straightforward to observe and have been successfully reduced in many developed cities through air quality policy interventions. Longer chain hydrocarbons released from diesel vehicles are not considered explicitly as part of air quality strategies and there are few direct measurements of their gaseous abundance in the atmosphere. This study describes the chemically comprehensive and continuous measurements of organic compounds in a developed megacity (London, which demonstrate that on a seasonal median basis, diesel-related hydrocarbons represent only 20–30 % of the total hydrocarbon mixing ratio but comprise more than 50 % of the atmospheric hydrocarbon mass and are a dominant local source of secondary organic aerosols. This study shows for the first time that 60 % of the winter primary hydrocarbon hydroxyl radical reactivity is from diesel-related hydrocarbons and using the maximum incremental reactivity scale, we predict that they contribute up to 50 % of the ozone production potential in London. Comparing real-world urban composition with regulatory emissions inventories in the UK and US highlights a previously unaccounted for, but very significant, under-reporting of diesel-related hydrocarbons; an underestimation of a factor ~4 for C9 species rising to a factor of over 70 for C12 during winter. These observations show that hydrocarbons from diesel vehicles can dominate gas phase reactive carbon in cities with high diesel fleet fractions. Future control of urban particulate matter and ozone in such locations requires a shift in policy focus onto gas phase hydrocarbons released from diesels as this vehicle type continues to displace gasoline world-wide.

  7. Control of hydrocarbon content of a reforming gas by using a hydrogenation catalyst.

    Science.gov (United States)

    Inoue, Kenichiro; Kawamoto, Katsuya

    2010-01-01

    To control of hydrocarbon content in waste pyrolysis-gasification and reforming processes, the use of a hydrogenation catalyst was examined in a test system with a model gas. To reduce the concentration of benzene in the reforming gas, benzene was hydrogenated with a nickel catalyst. The catalyst is usually used to convert gas-phase unsaturated hydrocarbons to saturated hydrocarbons, and the benzene was converted to cyclohexane at a temperature range of about 130 to 180 degrees C in the presence of steam. However, the conversion to methane occurred at about 250 to 300 degrees C. Methane seems to be a useful conversion compound because it does not cohere as a light tar. Sometimes the reforming gas needs to be cooled for use as generator fuel. In this case, it is possible to avoid the tar cohesion if the benzene in the gas is converted to methane at about 300 degrees C after the reforming. Reduction of the efficiency of conversion to methane was not observed over a 60h reaction period. The lower hydrocarbons (ethylene, ethane, and propylene) were also converted to methane at about 300 degrees C. Conversion of benzene was also possible when other hydrocarbons were present at high concentrations.

  8. ECONOMETRIC MODELING OF THE DYNAMICS OF VOLUMES HYDROCARBONS OF SMALL OIL AND GAS ENTERPRISES

    Directory of Open Access Journals (Sweden)

    GORLOV A.V.

    2015-01-01

    Full Text Available In this paper investigates the principles of functioning of small oil and gas enterprises of Russia. The basic characteristics and socio-economic tasks performed by the small oil and gas enterprises. Made correlation and regression analysis, a result of which the pair correlation coefficients between the indicator of development of small oil and gas enterprises (volumes hydrocarbons and the factors that characterize the work environment of their operation; built regressions, describing the process of development of small oil and gas enterprises. With a view to forecasting the development of small oil and gas enterprises built production function of Cobb-Douglas and selected econometric model, has good predictive properties. Made predictive calculations dynamics of volumes hydrocarbons of small oil and gas enterprises on formulating scenarios for the planning period (2015-2016 years.

  9. Preliminary study on the origin identification of natural gas by the parameters of light hydrocarbon

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The light hydrocarbon composition of 209 natural gas samples and individual light hydrocarbon carbon isotopes of 53 natural gas samples from typical humic-sourced gas and sapropelic-sourced gas in the four basins of China have been determined and analyzed.Some identification parameters for humic-sourced gas and sapropelic-sourced gas are proposed or corrected.The differences of compound-specificδ13C value of individual light hydrocarbon between humic-sourced gas and sapropelic-sourced gas have been founded.The humic-sourced gas has the distribution ofδ13C benzene > -24‰,δ13C toluene >-23‰,δ13C cyclohexane >-24‰andδ13C methyl cyclohexane >-24‰,while the sapropelicsourced gas has the distribution ofδ13C benzene <-24‰,δ13C toluene <-24‰,δ13C cyclohexane <-24‰and δ13C methyl cyclohexane <-24‰.Among the components of C7 light hydrocarbon compound,such as normal heptane(nC7),methyl cyclohexane(MCH)and dimethyl cyclopentane(ΣDMCP),etc,relative contents of nC7 and MCH are influenced mainly by the source organic matter type of natural gas.Therefore,it is suggested that the gas with relative content of nC7 of more than 30%and relative content of MCH of less than 70%is sapropelic-sourced gas,while gas with relative content of nC7 of less than 35%and relative content of MCH of more than 50%is humic-sourced gas.Among components of C5-7 aliphatics, the gas with relative content of C5-7 normal alkane of more than 30%is sapropelic-sourced gas,while the gas with relative content of C5-7 normal alkane of less than 30%is humic-sourced gas.These paremeters have been suggested to identify humic-sourced gas and sapropelic-sourced gas.

  10. Conversion of natural gas to C2 hydrocarbons through dielectric-barrier discharge plasma catalysis

    Institute of Scientific and Technical Information of China (English)

    王保伟; 许根慧

    2002-01-01

    The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 mL@min?1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons is 76%, and the total selectivity of C2 hydrocarbons and C3 hydrocarbons is nearly 100%. The conversion of methane increases with the increase of voltage and decreases with the flow of methane increase; the selectivity of C2 hydrocarbons decreases with the increase of voltage and increases with the flow of methane increase. The selectivity of C2 hydrocarbons is improved with catalyst for conversion of natural gas to C2 hydrocarbons in plasma field. Methane molecule collision with radicals is mainly responsible for product formation.

  11. Oil-shale gasification for obtaining of gas for synthesis of aliphatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Strizhakova, Yu. [Samara State Univ. (Russian Federation); Avakyan, T.; Lapidus, A.L. [I.M. Gubkin Russian State Univ. of Oil and Gas, Moscow (Russian Federation)

    2011-07-01

    Nowadays, the problem of qualified usage of solid fossil fuels as raw materials for obtaining of motor fuels and chemical products is becoming increasingly important. Gasification with further processing of gaseous products is a one of possible ways of their use. Production of synthesis gas with H{sub 2}/CO ratio equal 2 is possible by gasification of oil-shale. This gas is converted into the mixture of hydrocarbons over cobalt catalyst at temperature from 160 to 210 C at atmospheric pressure. The hydrocarbons can be used as motor, including diesel, or reactive fuel. (orig.)

  12. Process and catalyst for converting synthesis gas to liquid hydrocarbon mixture

    Science.gov (United States)

    Rao, V. Udaya S.; Gormley, Robert J.

    1987-01-01

    Synthesis gas containing CO and H.sub.2 is converted to a high-octane hydrocarbon liquid in the gasoline boiling point range by bringing the gas into contact with a heterogeneous catalyst including, in physical mixture, a zeolite molecular sieve, cobalt at 6-20% by weight, and thoria at 0.5-3.9% by weight. The contacting occurs at a temperature of 250.degree.-300.degree. C., and a pressure of 10-30 atmospheres. The conditions can be selected to form a major portion of the hydrocarbon product in the gasoline boiling range with a research octane of more than 80 and less than 10% by weight aromatics.

  13. [Characterization of aromatic hydrocarbons in heavy gas oil using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry].

    Science.gov (United States)

    Guo, Kun; Zhou, Jian; Liu, Zelong

    2012-02-01

    An analytical method for separating and identifying the aromatic hydrocarbons in heavy gas oil using comprehensive two-dimensional gas chromatography (GC x GC) coupled to time-of-flight mass spectrometry (TOF MS) was established. The two-dimensional distribution by ring number of the aromatic hydrocarbons was obtained. Besides phenanthrene and methyl-phenanthrene, many other polycyclic aromatic hydrocarbons (PAHs) such as pyrene and benzo [a] anthracene were identified by using the retention times, standard mass spectra or literature reports. The method was successfully applied to the hydrotreating process of heavy gas oil and the hydrotreated products of phenanthrene, pyrene were identified. This method provided technical support for the characterization of aromatic hydrocarbons in heavy gas oil and the investigation of hydrogenation mechanism of polycyclic aromatic hydrocarbons. Compared with the conventional method, gas chromatography coupled to mass spectrometry (GC-MS), the GC x GC-TOF MS method illustrated the obvious advantages for heavy gas oil analysis.

  14. Application of pyrolysis gas chromatography technique to evaluation of coal-generated hydrocarbon

    Institute of Scientific and Technical Information of China (English)

    孙永革; 盛国英; 傅家谟

    1997-01-01

    Based on kerogen-generated hydrocarbon model, a new method to calculate hydrocarbon yields for coals and coaly samples was put forward by means of pyrolysis technique. At the same time, the empirical criteria suggested by Powell were revised. The threshold value was preliminarily defined as HC yields >30 mg HC per gram TOC for effective gas source rocks and >60 mg HC per gram TOC for effective oil source rocks. Additionally, it was also confirmed that the relative compositions of the three ranges of C1-C5 total hydrocarbons, C6-C14 n-alkanes plus n-alkenes and C15+ n-alkanes plus n-alkenes from pyrolysates can be effectively used to distinguish the coal-generated hydrocarbon types.

  15. Safety barriers on oil and gas platforms. Means to prevent hydrocarbon releases

    Energy Technology Data Exchange (ETDEWEB)

    Sklet, Snorre

    2005-12-15

    The main objective of the PhD project has been to develop concepts and methods that can be used to define, illustrate, analyse, and improve safety barriers in the operational phase of offshore oil and gas production platforms. The main contributions of this thesis are; Clarification of the term safety barrier with respect to definitions, classification, and relevant attributes for analysis of barrier performance Development and discussion of a representative set of hydrocarbon release scenarios Development and testing of a new method, BORA-Release, for qualitative and quantitative risk analysis of hydrocarbon releases Safety barriers are defined as physical and/or non-physical means planned to prevent, control, or mitigate undesired events or accidents. The means may range from a single technical unit or human actions, to a complex socio-technical system. It is useful to distinguish between barrier functions and barrier systems. Barrier functions describe the purpose of safety barriers or what the safety barriers shall do in order to prevent, control, or mitigate undesired events or accidents. Barrier systems describe how a barrier function is realized or executed. If the barrier system is functioning, the barrier function is performed. If a barrier function is performed successfully, it should have a direct and significant effect on the occurrence and/or consequences of an undesired event or accident. It is recommended to address the following attributes to characterize the performance of safety barriers; a) functionality/effectiveness, b) reliability/ availability, c) response time, d) robustness, and e) triggering event or condition. For some types of barriers, not all the attributes are relevant or necessary in order to describe the barrier performance. The presented hydrocarbon release scenarios include initiating events, barrier functions introduced to prevent hydrocarbon releases, and barrier systems realizing the barrier functions. Both technical and human

  16. Safety barriers on oil and gas platforms. Means to prevent hydrocarbon releases

    Energy Technology Data Exchange (ETDEWEB)

    Sklet, Snorre

    2005-12-15

    The main objective of the PhD project has been to develop concepts and methods that can be used to define, illustrate, analyse, and improve safety barriers in the operational phase of offshore oil and gas production platforms. The main contributions of this thesis are; Clarification of the term safety barrier with respect to definitions, classification, and relevant attributes for analysis of barrier performance Development and discussion of a representative set of hydrocarbon release scenarios Development and testing of a new method, BORA-Release, for qualitative and quantitative risk analysis of hydrocarbon releases Safety barriers are defined as physical and/or non-physical means planned to prevent, control, or mitigate undesired events or accidents. The means may range from a single technical unit or human actions, to a complex socio-technical system. It is useful to distinguish between barrier functions and barrier systems. Barrier functions describe the purpose of safety barriers or what the safety barriers shall do in order to prevent, control, or mitigate undesired events or accidents. Barrier systems describe how a barrier function is realized or executed. If the barrier system is functioning, the barrier function is performed. If a barrier function is performed successfully, it should have a direct and significant effect on the occurrence and/or consequences of an undesired event or accident. It is recommended to address the following attributes to characterize the performance of safety barriers; a) functionality/effectiveness, b) reliability/ availability, c) response time, d) robustness, and e) triggering event or condition. For some types of barriers, not all the attributes are relevant or necessary in order to describe the barrier performance. The presented hydrocarbon release scenarios include initiating events, barrier functions introduced to prevent hydrocarbon releases, and barrier systems realizing the barrier functions. Both technical and human

  17. Fundamentals of natural gas processing - hydrocarbon dew point meter modelling

    OpenAIRE

    Michalsen, Kathrine; Nævdal, Helene Sire

    2014-01-01

    When natural gas is taken from the reservoir it needs to be refined by removing liquid and other impurities in order to prevent hydrate formation in the pipelines and to keep the gas within sales specifications. Scrubbers, vertical separators, are used to remove the liquid and the efficiency of the scrubber has a great impact on the quality of the gas. To control the gas specifications and the efficiency of the scrubber, a dew point meter can be used. This tool will ideally provide the real d...

  18. Psychosocial risks and hydrocarbon leaks : an exploration of their relationship in the Norwegian oil and gas industry

    NARCIS (Netherlands)

    Bergh, L.I.V.; Ringstad, A.J.; Leka, S.; Zwetsloot, G.I.J.M.

    2014-01-01

    Hydrocarbon leaks have a major accident potential in the oil and gas industry. Over the years the oil and gas industry in Norway has worked hard to find means to prevent hydrocarbon leaks and is today able to report significant progress. In this context, the exploration of accidents in light of huma

  19. Drift-Scale THC Seepage Model

    Energy Technology Data Exchange (ETDEWEB)

    C.R. Bryan

    2005-02-17

    The purpose of this report (REV04) is to document the thermal-hydrologic-chemical (THC) seepage model, which simulates the composition of waters that could potentially seep into emplacement drifts, and the composition of the gas phase. The THC seepage model is processed and abstracted for use in the total system performance assessment (TSPA) for the license application (LA). This report has been developed in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2005 [DIRS 172761]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this report. The plan for validation of the models documented in this report is given in Section 2.2.2, ''Model Validation for the DS THC Seepage Model,'' of the TWP. The TWP (Section 3.2.2) identifies Acceptance Criteria 1 to 4 for ''Quantity and Chemistry of Water Contacting Engineered Barriers and Waste Forms'' (NRC 2003 [DIRS 163274]) as being applicable to this report; however, in variance to the TWP, Acceptance Criterion 5 has also been determined to be applicable, and is addressed, along with the other Acceptance Criteria, in Section 4.2 of this report. Also, three FEPS not listed in the TWP (2.2.10.01.0A, 2.2.10.06.0A, and 2.2.11.02.0A) are partially addressed in this report, and have been added to the list of excluded FEPS in Table 6.1-2. This report has been developed in accordance with LP-SIII.10Q-BSC, ''Models''. This report documents the THC seepage model and a derivative used for validation, the Drift Scale Test (DST) THC submodel. The THC seepage model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral

  20. Noble gases solubility models of hydrocarbon charge mechanism in the Sleipner Vest gas field

    Science.gov (United States)

    Barry, P. H.; Lawson, M.; Meurer, W. P.; Warr, O.; Mabry, J. C.; Byrne, D. J.; Ballentine, C. J.

    2016-12-01

    Noble gases are chemically inert and variably soluble in crustal fluids. They are primarily introduced into hydrocarbon reservoirs through exchange with formation waters, and can be used to assess migration pathways and mechanisms, as well as reservoir storage conditions. Of particular interest is the role groundwater plays in hydrocarbon transport, which is reflected in hydrocarbon-water volume ratios. Here, we present compositional, stable isotope and noble gas isotope and abundance data from the Sleipner Vest field, in the Norwegian North Sea. Sleipner Vest gases are generated from primary cracking of kerogen and the thermal cracking of oil. Gas was emplaced into the Sleipner Vest from the south and subsequently migrated to the east, filling and spilling into the Sleipner Ost fields. Gases principally consist of hydrocarbons (83-93%), CO2 (5.4-15.3%) and N2 (0.6-0.9%), as well as trace concentrations of noble gases. Helium isotopes (3He/4He) are predominantly radiogenic and range from 0.065 to 0.116 RA; reported relative to air (RA = 1.4 × 10-6; Clarke et al., 1976; Sano et al., 1988), showing predominantly (>98%) crustal contributions, consistent with Ne (20Ne/22Ne from 9.70 to 9.91; 21Ne/22Ne from 0.0290 to 0.0344) and Ar isotopes (40Ar/36Ar from 315 to 489). Air-derived noble gas isotopes (20Ne, 36Ar, 84Kr, 132Xe) are introduced into the hydrocarbon system by direct exchange with air-saturated water (ASW). The distribution of air-derived noble gas species are controlled by phase partitioning processes; in that they preferentially partition into the gas (i.e., methane) phase, due to their low solubilities in fluids. Therefore, the extent of exchange between hydrocarbon phases and formation waters - that have previously equilibrated with the atmosphere - can be determined by investigating air-derived noble gas species. We utilize both elemental ratios to address process (i.e., open vs. closed system) and concentrations to quantify the extent of hydrocarbon

  1. Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2016-12-01

    Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

  2. Analysis of siloxanes in hydrocarbon mixtures using comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Ghosh, Abhijit; Seeley, Stacy K; Nartker, Steven R; Seeley, John V

    2014-09-19

    A comprehensive two-dimensional gas chromatography (GC×GC) method for separating siloxanes from hydrocarbons has been developed using a systematic process. First, the retention indices of a set of siloxanes and a set of hydrocarbons were determined on 6 different stationary phases. The retention indices were then used to model GC×GC separation on 15 different stationary phase pairs. The SPB-Octyl×DB-1 pair was predicted to provide the best separation of the siloxanes from the hydrocarbons. The efficacy of this stationary phase pair was experimentally tested by performing a GC×GC analysis of gasoline spiked with siloxanes and by analyzing biogas obtained from a local wastewater treatment facility. The model predictions agreed well with the experimental results. The SPB-Octyl×DB-1 stationary phase pair constrained the hydrocarbons to a narrow range of secondary retention times and fully isolated the siloxanes from the hydrocarbon band. The resulting GC×GC method allows siloxanes to be resolved from complex mixtures of hydrocarbons without requiring the use of a selective detector.

  3. Hydrocarbon emissions from gas engine CHP-units. 2011 measurement program

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, G.H.J. [KEMA, Arnhem (Netherlands)

    2012-06-15

    In December 2009, the Ministry of Infrastructure and Environment (IandM) issued the Decree on Emission Limits for Middle Sized Combustion Installations (BEMS). This decree imposes a first-time emission limit value (ELV) of 1500 mg C/m{sup 3}{sub o} at 3% O{sub 2} for hydrocarbons emitted by gas engines. IandM used the findings of two hydrocarbon emission measurement programs, executed in 2007 and 2009, as a guideline for this initial ELV. The programs did reveal substantial variation in the hydrocarbon emissions of the gas engines tested. This variation, and especially the uncertainty as to the role of engine and/or other parameters causing such variation, was felt to hamper further policy development. IandM therefore commissioned KEMA to perform follow-up measurements on ten gas engine CHP-units in 2011. Aim of this 2011 program is to assess hydrocarbon emission variation in relation to engine parameters and process conditions including maintenance status, and to atmospheric conditions. The 2011 program comprised two identical measurement sessions, one in spring and one in winter.

  4. Distribution of major hydrocarbon source rocks in the major oil-gas-bearing basins in China

    Institute of Scientific and Technical Information of China (English)

    LIU Luofu; ZHAO Suping; CHEN Lixin; HUO Hong

    2005-01-01

    The distribution characteristics of major hydrocarbon source rocks in the major oil-gas-bearing basins in China were discussed in this paper, and differences between the East and the West basins in tectonic setting, age, lithology, sedimentary environment, and hydrocarbon generation feature and potential were also studied. Considering the Lüliang Mountains-Dalou Mountains as the boundary, source rocks in the East basins are distributed mainly in three NNE-trend subsiding belts, and those in the West basins are distributed in the north and south of the Tianshan Mountains and Qilian Mountains. They are mainly NWW trending and can be divided into four basin groups.

  5. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    Science.gov (United States)

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar).

  6. Process for the separation of C sub 2 hydrocarbons from natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, H.; Sapper, R.

    1990-08-21

    A process for the separation of C{sub 2+} hydrocarbons from natural gas under pressure is disclosed, in which the natural gas is cooled, partially condensed, and separated into a liquid fraction and a gaseous fraction. The liquid fraction is subcooled and then expanded into the upper zone of a rectifying column. The gaseous fraction, after engine expansion, is also introduced into the rectifying column. During rectification, a product stream containing essentially C{sub 2+} hydrocarbons and a residual gas stream containing predominantly lower-boiling components are obtained. The residual gas stream is initially heated by heat exchange with the liquid fraction and then heated by heat exchange with the gaseous fraction obtained after partial condensation. The residual gas stream is then further heated by heat exchange with the feed stream of natural gas to be partially condensed. The heated residual gas is then engine expanded and reheated again by heat exchange with the feed stream of natural gas to be partially condensed.

  7. Surface geochemical data evaluation and integration with geophysical observations for hydrocarbon prospecting, Tapti graben, Deccan Syneclise, India

    Institute of Scientific and Technical Information of China (English)

    T. Satish Kumar; A.M. Dayal; V. Sudarshan

    2014-01-01

    The Deccan Syneclise is considered to have significant hydrocarbon potential. However, significant hydrocarbon discoveries, particularly for Mesozoic sequences, have not been established through conventional exploration due to the thick basalt cover over Mesozoic sedimentary rocks. In this study, near-surface geochemical data are used to understand the petroleum system and also investigate type of source for hydrocarbons generation of the study area. Soil samples were collected from favorable areas identified by integrated geophysical studies. The compositional and isotopic signatures of adsorbed gaseous hydrocarbons (methane through butane) were used as surface indicators of pe-troleum micro-seepages. An analysis of 75 near-surface soil-gas samples was carried out for light hydrocarbons (C1-C4) and their carbon isotopes from the western part of Tapti graben, Deccan Syneclise, India. The geochemical results reveal sites or clusters of sites containing anomalously high concentrations of light hydrocarbon gases. High concentrations of adsorbed thermogenic methane (C1 =518 ppb) and ethane plus higher hydrocarbons (∑C2+=977 ppb) were observed. Statistical analysis shows that samples from 13% of the samples contain anomalously high concentrations of light hydrocarbons in the soil-gas constituents. This seepage suggests largest magnitude of soil gas anomalies might be generated/source from Mesozoic sedimentary rocks, beneath Deccan Traps. The carbon isotopic composition of methane, ethane and propane ranges are from -22.5‰ to -30.2‰PDB, -18.0‰ to 27.1‰ PDB and 16.9‰e-32.1‰ PDB respectively, which are in thermogenic source. Surface soil sample represents the intersection of a migration conduit from the deep subsurface to the surface connected to sub-trappean Mesozoic sedimentary rocks. Prominent hydrocarbon concentra-tions were associated with dykes, lineaments and presented on thinner basaltic cover in the study area, which probably acts as channel for the

  8. The evolution of Devonian hydrocarbon gases in shallow aquifers of the northern Appalachian Basin: Insights from integrating noble gas and hydrocarbon geochemistry

    Science.gov (United States)

    Darrah, Thomas H.; Jackson, Robert B.; Vengosh, Avner; Warner, Nathaniel R.; Whyte, Colin J.; Walsh, Talor B.; Kondash, Andrew J.; Poreda, Robert J.

    2015-12-01

    The last decade has seen a dramatic increase in domestic energy production from unconventional reservoirs. This energy boom has generated marked economic benefits, but simultaneously evoked significant concerns regarding the potential for drinking-water contamination in shallow aquifers. Presently, efforts to evaluate the environmental impacts of shale gas development in the northern Appalachian Basin (NAB), located in the northeastern US, are limited by: (1) a lack of comprehensive "pre-drill" data for groundwater composition (water and gas); (2) uncertainty in the hydrogeological factors that control the occurrence of naturally present CH4 and brines in shallow Upper Devonian (UD) aquifers; and (3) limited geochemical techniques to quantify the sources and migration of crustal fluids (specifically methane) at various time scales. To address these questions, we analyzed the noble gas, dissolved ion, and hydrocarbon gas geochemistry of 72 drinking-water wells and one natural methane seep all located ≫1 km from shale gas drill sites in the NAB. In the present study, we consciously avoided groundwater wells from areas near active or recent drilling to ensure shale gas development would not bias the results. We also intentionally targeted areas with naturally occurring CH4 to characterize the geochemical signature and geological context of gas-phase hydrocarbons in shallow aquifers of the NAB. Our data display a positive relationship between elevated [CH4], [C2H6], [Cl], and [Ba] that co-occur with high [4He]. Although four groundwater samples show mantle contributions ranging from 1.2% to 11.6%, the majority of samples have [He] ranging from solubility levels (∼45 × 10-6 cm3 STP/L) with below-detectable [CH4] and minor amounts of tritiogenic 3He in low [Cl] and [Ba] waters, up to high [4He] = 0.4 cm3 STP/L with a purely crustal helium isotopic end-member (3He/4He = ∼0.02 times the atmospheric ratio (R/Ra)) in samples with CH4 near saturation for shallow

  9. International comparison of a hydrocarbon gas standard at the picomol per mol level.

    Science.gov (United States)

    Rhoderick, George C; Duewer, David L; Apel, Eric; Baldan, Annarita; Hall, Bradley; Harling, Alice; Helmig, Detlev; Heo, Gwi Suk; Hueber, Jacques; Kim, Mi Eon; Kim, Yong Doo; Miller, Ben; Montzka, Steve; Riemer, Daniel

    2014-03-04

    Studies of climate change increasingly recognize the diverse influences of hydrocarbons in the atmosphere, including roles in particulates and ozone formation. Measurements of key nonmethane hydrocarbons (NMHCs) suggest atmospheric mole fractions ranging from low picomoles per mol (ppt) to nanomoles per mol (ppb), depending on location and compound. To accurately establish mole fraction trends and to relate measurement records from many laboratories and researchers, it is essential to have accurate, stable, calibration standards. In February of 2008, the National Institute of Standards and Technology (NIST) developed and reported on picomoles per mol standards containing 18 nonmethane hydrocarbon compounds covering the mole fraction range of 60 picomoles per mol to 230 picomoles per mol. The stability of these gas mixtures was only characterized over a short time period (2 to 3 months). NIST recently prepared a suite of primary standard gas mixtures by gravimetric dilution to ascertain the stability of the 2008 picomoles per mol NMHC standards suite. The data from this recent chromatographic intercomparison of the 2008 to the 2011 suites confirm a much longer stability of almost 5 years for 15 of the 18 hydrocarbons; the double-bonded alkenes of propene, isobutene, and 1-pentene showed instability, in line with previous publications. The agreement between the gravimetric values from preparation and the analytical mole fractions determined from regression illustrate the internal consistency of the suite within ±2 pmol/mol. However, results for several of the compounds reflect stability problems for the three double-bonded hydrocarbons. An international intercomparison on one of the 2008 standards has also been completed. Participants included National Metrology Institutes, United States government laboratories, and academic laboratories. In general, results for this intercomparison agree to within about ±5% with the gravimetric mole fractions of the hydrocarbons.

  10. Hydrocarbon phenotyping of algal species using pyrolysis-gas chromatography mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kothari Shankar L

    2010-05-01

    Full Text Available Abstract Background Biofuels derived from algae biomass and algae lipids might reduce dependence on fossil fuels. Existing analytical techniques need to facilitate rapid characterization of algal species by phenotyping hydrocarbon-related constituents. Results In this study, we compared the hydrocarbon rich algae Botryococcus braunii against the photoautotrophic model algae Chlamydomonas reinhardtii using pyrolysis-gas chromatography quadrupole mass spectrometry (pyGC-MS. Sequences of up to 48 dried samples can be analyzed using pyGC-MS in an automated manner without any sample preparation. Chromatograms of 30-min run times are sufficient to profile pyrolysis products from C8 to C40 carbon chain length. The freely available software tools AMDIS and SpectConnect enables straightforward data processing. In Botryococcus samples, we identified fatty acids, vitamins, sterols and fatty acid esters and several long chain hydrocarbons. The algae species C. reinhardtii, B. braunii race A and B. braunii race B were readily discriminated using their hydrocarbon phenotypes. Substructure annotation and spectral clustering yielded network graphs of similar components for visual overviews of abundant and minor constituents. Conclusion Pyrolysis-GC-MS facilitates large scale screening of hydrocarbon phenotypes for comparisons of strain differences in algae or impact of altered growth and nutrient conditions.

  11. Evidence of shallow hydrocarbons offshore northern Santa Cruz county, California

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, H.T.; Nagel, D.K.

    1982-08-01

    Analyses of high-resolution seismic reflection profiles and hydrocarbon samples indicate that natural hydrocarbon seepage is occurring along the San Gregorio and Monterey Bay fault zones offshore northern Santa Cruz County, California. A variety of anomalous seismic reflection features such as a water-column anomalies, subsurface amplitude anomalies (''bright spots''), and seismic ''smears/wipeouts'' has been observed and mapped. More than 100 water-column anomalies (probably gas seeps) occur in the study area of approximately 270 mi/sup 2/ (700 km/sup 2/). Many of these seismic anomalies are associated with subsurface geologic structures, which suggest hydrocarbon migration from depth. Samples of natural gas collected from a shallow coastal water well contain 74 to 91% methane, 7 to 23% nitrogen, approx.2% carbon dioxide, and < 1% ethane. The methane appears to be thermogenic in origin, having delta/sup 13/C values of -29.51 to -32.55% PDB. Rock dredges from 2,300 ft (700 m) of water in Ascension Submarine Canyon have also recovered oil-saturated sandstones, further suggesting the seepage of hydrocarbons. The shallow occurrence of most of these hydrocarbons are interpreted to be the result of migration from depth along active faults within the San Gregorio and Monterey Bay faults zones.

  12. Analysis of aromatic hydrocarbons in petroleum fractions using gas chromatography, mass spectrometry and mass fragmentrography

    Energy Technology Data Exchange (ETDEWEB)

    Kubelka, V.

    1980-01-01

    Mass spectrometry in combination with gas chrom. used to analyze hydrocarbon mixtures results in qualit. and semi-quant. data regarding composition of the analyzed mixture. Use of mass fragmentrography during chromatographic separation will allow simultaneous recording of changes in intensity of characteristic ions and thus determine the retention index, for this substance. Combining mass spectre and retention index, it is possible to identify the given subst. or limit the number of possible combinations.

  13. Analysis of 23 polycyclic aromatic hydrocarbons in smokeless tobacco by gas chromatography-mass spectrometry

    OpenAIRE

    Stepanov, Irina; Villalta, Peter W.; Knezevich, Aleksandar; Jensen, Joni; Hatsukami, Dorothy; Hecht, Stephen S.

    2010-01-01

    Smokeless tobacco contains 28 known carcinogens and causes precancerous oral lesions and oral and pancreatic cancer. A recent study conducted by our research team identified 8 different polycyclic aromatic hydrocarbons (PAH) in U.S. moist snuff, encouraging further investigations of this group of toxicants and carcinogens in smokeless tobacco products. In this study, we developed a gas chromatography-mass spectrometry method that allows simultaneous analysis of 23 various PAH in smokeless tob...

  14. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How must I measure gas flaring or venting... SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid...

  15. Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter Emitted from Burning Kerosene, Liquid Petroleum Gas, and Wood Fuels in Household Cookstoves

    Science.gov (United States)

    This study measured polycyclic aromatic hydrocarbon (PAH) composition in particulate matter emissions from residential cookstoves. A variety of fuel and cookstove combinations were examined, including: (i) liquid petroleum gas (LPG), (ii) kerosene in a wick stove, (iii) wood (10%...

  16. Polycyclic aromatic hydrocarbon ionization as a tracer of gas flows through protoplanetary disk gaps

    OpenAIRE

    Maaskant, K. M.; Min, M.; Waters, L. B. F. M.; Tielens, A. G. G. M.

    2014-01-01

    Context. Planet-forming disks of gas and dust around young stars contain polycyclic aromatic hydrocarbons (PAHs). Aims. We aim to characterize how the charge state of PAHs can be used as a probe of flows of gas through protoplanetary gaps. In this context, our goal is to understand the PAH spectra of four transitional disks. In addition, we want to explain the observed correlation between PAH ionization (traced by the I6.2/I11.3 feature ratio) and the disk mass (traced by the 1.3 mm luminosit...

  17. 瓦斯压力对卸荷原煤力学及渗透特性的影响%Influence of gas pressure on mechanical and seepage characteristics of coal under unloading condition

    Institute of Scientific and Technical Information of China (English)

    尹光志; 李铭辉; 李文璞; 蒋长宝; 曹偈; 张千贵

    2012-01-01

    运用自主研制的含瓦斯煤热流固耦合三轴伺服渗流试验装置,以原煤煤样作为研究对象,在不同瓦斯压力条件下对含瓦斯煤进行了固定轴向应力的卸围压瓦斯渗流试验,研究卸围压过程中瓦斯压力对煤体的力学及渗透特性的影响。研究结果表明:开始卸围压后,煤体出现明显的扩容现象,径向发生明显膨胀应变,煤体中的渗流通道张开,煤体中瓦斯的渗流速率随之加快;随着瓦斯压力的升高,解除单位围压后煤样产生的变形变大,渗流速率升高的速率也随之增大;瓦斯压力越高,煤样从开始卸围压起至破坏的时间越短,即煤体强度越低;在卸围压初始阶段,煤样变形模量变化不大,在进入屈服阶段和失稳破坏阶段后,煤样的变形模量减小的速率开始明显加快。从煤样开始卸围压至破坏之前,煤样的变形模量下降了3.71%~7.45%;煤样的泊松比逐渐增大,围压与泊松比的对应具有较为明显的幂函数关系。%Based on domestic-developed triaxial servo-controlled seepage equipment for thermal-hydrological-mechani- cal coupling of coal containing methane, the experimental study of unloading confining pressure of coal was performed on coal samples under different gas pressure. The results show that the characteristic of distinct dilatancy is displayed in the process of unloading confining pressure, therefore seepage channels in coal body are extended and seepage ve- locity increases. The deformation of coal containing methane per unit decreased confining pressure and seepage velocity increases with the increase in gas pressure in the same stress paths. The compressive strength decreases gradually with the increase of gas pressure. In the initial stage of unloading confining pressure, deformation modulus of coal containing methane changes little. After the yielding occurs, it decreases obviously. The deformation modulus decreases 3.71% - 7.45 % in the process of

  18. Determination of Beeswax Hydrocarbons by Gas Chromatography with a Mass Detector (GC -MS Technique

    Directory of Open Access Journals (Sweden)

    Waś Ewa

    2014-06-01

    Full Text Available Here we describe a method of hydrocarbon (alkanes, alkenes, dienes identification and quantitative determination of linear saturated hydrocarbons (n-alkanes in beeswax using gas chromatography with a mass detector technique (GC -MS . Beeswax hydrocarbons were isolated using a solid-phase extraction (SPE technique with neutral aluminum oxide (Alumina - N, 1000 mg, 6 mL, then were separated on a non-polar gas chromatography column ZB-5HT INFERNO (20 m×0.18 mm×0.18 μm. Qquantitative analysis of n-alkanes was conducted by the method of internal standard with squalane used as the internal standard. The basic parameters of validation (linearity and working range, limit of determination, repeatability and reproducibility, recovery were determined. For all of the identified compounds, satisfactory (≥0.997 coefficients of correlation in the working ranges of the method (from 0.005 to 5.0 g/100 g were obtained. The elaborated method was characterized by satisfactory repeatability and within-laboratory reproducibility. The average coefficients of variation for the total n-alkanes did not exceed 2% under conditions of repeatability or 4% under conditions of reproducibility. The recovery for individual n-alkanes was above 94%; for their total content, it was 100.5%. In beeswax originating from Apis mellifera, n-alkanes containing from 20 to 35 carbon atoms in their molecules were determined. The total content of these alkanes was between 9.08 g and 10.86 g/100 g (on average, 9.81 g/100 g. Additionally, apart from the saturated hydrocarbons, unsaturated hydrocarbons and dienes were identified.

  19. Determination of Diffusion Coefficients of Selected Long Chain Hydrocarbons using Reversed- Flow Gas Chromatographic Technique

    Directory of Open Access Journals (Sweden)

    Khalisanni Khalid

    2011-01-01

    Full Text Available The reversed-flow gas chromatography (RF-GC technique was used to study the evaporation rate and estimating the diffusion coefficient of samples. The RF-GC system comprises of six-port valve, sampling and diffusion column, detector and modified commercial gas chromatography machine. Selected long chain of hydrocarbons (99.99% purity was used as samples. The solute (stationary phase were carried out by carrier gas (mobile phase to the detector. The data obtained from the RF-GC analysis were analysed by deriving the elution curve of the sample peaks using mathematical expression to find the diffusion coefficients values of respective liquids. The values obtained were compared with theoretical values to ensure the accuracy of readings. The interesting findings of the research showed the theoretical values of equilibrium at liquid-gas interphase lead to profound an agreement with the experimental evidence, which contributes for the references of future studies.

  20. Comprehensive two-dimensional gas chromatography for characterizing mineral oils in foods and distinguishing them from synthetic hydrocarbons.

    Science.gov (United States)

    Biedermann, Maurus; Grob, Koni

    2015-01-02

    Many foods are contaminated by hydrocarbons of mineral oil or synthetic origin. High performance liquid chromatography on-line coupled with gas chromatography and flame ionization detection (HPLC-GC-FID) is a powerful tool for the quantitative determination, but it would often be desirable to obtain more information about the type of hydrocarbons in order to identify the source of the contamination and specify pertinent legislation. Comprehensive two-dimensional gas chromatography (GC×GC) is shown to produce plots distinguishing mineral oil saturated hydrocarbons (MOSH) from polymer oligomeric saturated hydrocarbons (POSH) and characterizing the degree of raffination of a mineral oil. The first dimension separation occurred on a phenyl methyl polysiloxane, the second on a dimethyl polysiloxane. Mass spectrometry (MS) was used for identification, FID for quantitative determination. This shows the substantial advances in chromatography to characterize complex hydrocarbon mixtures even as contaminants in food.

  1. Conversion of associated natural gas to liquid hydrocarbons. Final report, June 1, 1995--January 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The original concept envisioned for the use of Fischer-Tropsch processing (FTP) of United States associated natural gas in this study was to provide a way of utilizing gas which could not be brought to market because a pipeline was not available or for which there was no local use. Conversion of gas by FTP could provide a means of utilizing offshore associated gas which would not require installation of a pipeline or re-injection. The premium quality F-T hydrocarbons produced by conversion of the gas can be transported in the same way as the crude oil or in combination (blended) with it, eliminating the need for a separate gas transport system. FTP will produce a synthetic crude oil, thus increasing the effective size of the resource. The two conventional approaches currently used in US territory for handling of natural gas associated with crude petroleum production are re-injection and pipelining. Conversion of natural gas to a liquid product which can be transported to shore by tanker can be accomplished by FTP to produce hydrocarbons, or by conversion to chemical products such as methanol or ammonia, or by cryogenic liquefaction (LNG). This study considers FTP and briefly compares it to methanol and LNG. The Energy International Corporation cobalt catalyst, ratio adjusted, slurry bubble column F-T process was used as the basis for the study and the comparisons. An offshore F-T plant can best be accommodated by an FPSO (Floating Production, Storage, Offloading vessel) based on a converted surplus tanker, such as have been frequently used around the world recently. Other structure types used in deep water (platforms) are more expensive and cannot handle the required load.

  2. Conversion of natural gas to C2 hydrocarbons through dielectric-barrier discharge plasma catalysis

    Institute of Scientific and Technical Information of China (English)

    王保伟; 许根慧

    2002-01-01

    The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons i

  3. Sediment biogeochemistry and microbial activity at natural hydrocarbon seeps and at sites impacted by anthropogenic hydrocarbon discharges

    Science.gov (United States)

    Joye, S. B.; Sibert, R.; Battles, J.; Fields, L.; Kleindienst, S.; Crespo-Medina, M.; Hunter, K.; Meile, C. D.; Montoya, J. P.

    2013-12-01

    Natural hydrocarbon seeps occur along the seafloor where geologic faults facilitate transfer of deeply sourced fluids enriched in gas, oil, and dissolved organic matter through shallow sediments and into the water column. At natural seeps, microbial populations specialize in hydrocarbon degradation and rates of microbial activity, including sulfate reduction and anaerobic oxidation of methane, can be extremely high. As a result, the biogeochemical signature of sediments near areas of active natural seepage is distinct: high concentrations of metabolic end products, such as dissolved inorganic carbon and hydrogen sulfide, abound, and often, high dissolved inorganic carbon concentrations result in the precipitation of authigenic carbonate minerals. We examined microbial processes and biogeochemical signatures at two natural seeps, Green Canyon 600 and Mississippi Canyon 118. Higher and more frequent seepage loci at the Green Canyon 600 site led to more widespread hotspots of elevated microbial activity and distinct geochemistry. However, rates of microbial activity were comparable at the two sites in areas of active hydrocarbon seepage. The microbial communities at the two sites were surprisingly different. The second group of sites was impacted by anthropogenic hydrocarbon discharges instead of natural seepage. One site, Oceanus 26, lies near the Deepwater Horizon/Macondo wellhead and was impacted by weathered oil sedimentation during the Macondo discharge. The second set of impacted sites, noted as Taylor Energy, lie near a sunken platform and compromised riser, which have together resulted in persistent hydrocarbon discharge to the adjacent oceanic system for more than 6 years. Rates of microbial activity in the upper sediments at Oceanus 26 were depressed relative to activity in the deeper layers, suggesting inhibition by the presence of weathered oil or an microbial community unable to weather the carbon available in the layer. At the Taylor energy site

  4. Stable Isotopic Constraints on Abiogenic Hydrocarbon gas Contributions to Thermogenic Natural gas Resources in the Northern Appalachian Basin, USA

    Science.gov (United States)

    Burruss, R. C.; Laughrey, C. D.

    2006-05-01

    The generation of abiogenic methane by serpentinization or by graphite-water reactions in high-grade metamorphic rocks is well documented by isotopic, fluid inclusion, and petrographic studies. However, geochemical evidence is equivocal for abiogenic generation of higher hydrocarbon gases (ethane through pentane) in economic resources. Thermogenic hydrocarbon gases, generated by thermal cracking of sedimentary organic matter of biological origin, are progressively enriched in 13C as a function of increasing number of carbon atoms in the molecule. The isotopic composition is controlled by the kinetic isotope effect (KIE) during carbon-carbon bond breaking with the largest KIE for methane. Published work on gases in Precambrian rocks in Canada and South Africa suggest that some were generated by abiogenic Fischer-Tropsch type reactions that produced gases with carbon isotopic compositions that are reversed from the thermogenic trend. We have documented reversed isotopic compositions in natural gas accumulations in lower Paleozoic reservoirs of the Appalachian basin regionally from West Virginia and eastern Ohio through Pennsylvania to central New York. The regional accumulation in lower Silurian age strata shows progressive enhancement of the isotopic reversal with increasing depth in the basin. Multivariate analysis of the molecular and isotopic data define an end-member in the deep basin with an approximate composition of 98 mol % CH4, 1-2 mol % C2H6, -150‰, C1/C2+ up to 220). New isotopic studies of gas accumulations, gases in fluid inclusions, and of sedimentary organic matter in the Appalachian basin are in progress to constrain the possible contribution of abiogenic hydrocarbon generation to gas accumulations in this basin.

  5. Kinetic study of the hydrocarbon generation from marine carbonate source rocks characterization of products of gas and liquid hydrocarbon

    Institute of Scientific and Technical Information of China (English)

    GENG Xinhua; GENG Ansong; XIONG Yongqiang; LIU Jinzhong; ZHANG Haizu; ZHAO Qingfang

    2006-01-01

    The kinetic parameters of hydrocarbon generation from the marine carbonate source rocks were determined and calibrated through kinetic simulating experiment. The kinetic parameters of hydrocarbon generation then were extrapolated to geological condition by using the relative software.The result shows that gaseous hydrocarbons (C1, C2,C3, C4-5) were generated in condition of 150℃<T<220℃(1.0%<Ro <3.0% ). Light hydrocarbons (C6-13)and heavy hydrocarbons ( C13+) were generated in condition of 100 ℃<T<170 ℃ (0.5%<Ro<1.5%). A quantitative reference to examine the natural evolution of hydrocarbon of marine carbonate source rocks can be established through the results. It also provides a new method for evaluating the highly mature marine carbonate source rock more reasonably.

  6. Evaluation on occluded hydrocarbon in deep–ultra deep ancient source rocks and its cracked gas resources

    Directory of Open Access Journals (Sweden)

    Jian Li

    2015-12-01

    Full Text Available Oil-cracked gas, as the main type of high-over mature marine natural gas in China, is mainly derived from occluded hydrocarbon. So it is significant to carry out quantitative study on occluded hydrocarbon. In this paper, the occluded hydrocarbon volume of the main basins in China was calculated depending on their types, abundances and evolution stages by means of the forward method (experimental simulation and the inversion method (geologic profile dissection. And then, occluded hydrocarbon evolution models were established for five types of source rocks (sapropelic, sapropelic prone hybrid, humic prone hybrid, humic and coal. It is shown that the hydrocarbon expulsion efficiency of sapropelic and sapropelic prone hybrid excellent source rocks is lower than 30% at the low-maturity stage, 30%–60% at the principal oil generation stage, and 50%–80% at the high-maturity stage, which are all about 10% higher than that of humic prone hybrid and humic source rocks at the corresponding stages. The resource distribution and cracked gas expulsion of occluded hydrocarbon since the high-maturity stage of marine source rocks in the Sichuan Basin were preliminarily calculated on the basis of the evolution models. The cracked gas expulsion is 230.4 × 1012 m3 at the high evolution stage of occluded hydrocarbon of the Lower Cambrian Qiongzhusi Fm in this basin, and 12.3 × 1012 m3 from the source rocks of Sinian Doushantuo Fm, indicating good potential for natural gas resources. It is indicated that the favorable areas of occluded hydrocarbon cracked gas in the Qiongzhusi Fm source rocks in the Sichuan Basin include Gaoshiti–Moxi, Ziyang and Weiyuan, covering a favorable area of 4.3 × 104 km2.

  7. Bifurcation and catastrophe of seepage flow system in broken rock

    Institute of Scientific and Technical Information of China (English)

    MIAO Xie-xing; LI Shun-cai; CHEN Zhan-qing

    2009-01-01

    The study of dynamical behavior of water or gas flows in broken rock is a basic research topic among a series of key projects about stability control of the surrounding rocks in mines and the prevention of some disasters such as water inrush or gas outburst and the protection of the groundwater resource. It is of great theoretical and engineering importance in respect of promo-tion of security in mine production and sustainable development of the coal industry. According to the non-Darcy property of seepage flow in broken rock dynamic equations of non-Darcy and non-steady flows in broken rock are established. By dimensionless transformation, the solution diagram of steady-states satisfying the given boundary conditions is obtained. By numerical analysis of low relaxation iteration, the dynamic responses corresponding to the different flow parameters have been obtained. The stability analysis of the steady-states indicate that a saddle-node bifurcaton exists in the seepage flow system of broken rock. Consequently, using catastrophe theory, the fold catastrophe model of seepage flow instability has been obtained. As a result, the bifurcation curves of the seepage flow systems with different control parameters are presented and the standard potential function is also given with respect to the generalized state variable for the fold catastrophe of a dynamic system of seepage flow in broken rock.

  8. Method and facility for the recovery of hydrocarbons from a gas-air compound. Verfahren und Vorrichtung zur Rueckgewinnung von Kohlenwasserstoffen aus einem Gas-Luft-Gemisch

    Energy Technology Data Exchange (ETDEWEB)

    Hagenkoetter, M.; Hoelter, H.; Sdrojewski, R.

    1991-08-01

    A method or rather facility for the recovery of hydrocarbons from a gas-air compound works as follows: At first the gas-air compound is cooled down and brought to condensation. The hydrocarbons remaining in the gas-air compound after condensation are combusted in an internal combustion engine. The energy generated by the internal combustion engine is utilized for the operation of the cooling system planned for cooling and condensation. The cooling systen is developed and operated in a way that the gas-air compound is purified as far as possible from hydrocarbons and impurities when penetrating the cooling system. Behind the cooling system in front of the internal combustion engine fuel is apportioned to the gas-air compound.

  9. Simultaneous determination of aliphatic hydrocarbons, PCBs and PCTs in pork liver by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Barros, C. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Alvarez Pineiro, M.E. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Simal Lozano, J. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Lage Yusty, M.A. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain)

    1996-10-01

    A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C{sub 18}, C{sub 19}, C{sub 20}, C{sub 22}, C{sub 24}, C{sub 28}, C{sub 32} and C{sub 36}) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs; CV % (0.9-6.7) indicated the method to be both precise and reproducible. (orig.)

  10. The Role of Innovative Development in Unconventional Hydrocarbon Exploitation in the Context of the Shale Gas Revolution in the USA

    OpenAIRE

    2014-01-01

    Due to the recent drop in oil prices, there is a strong interest in the influence of the shale revolution on the global supply and demand of hydrocarbon fuels. Consequently, the attention of many economists and industry analysts is drawn to the technological, institutional and regulatory aspects of hydrocarbon production from shale deposits in the USA. The authors analyze factors facilitating the shale gas revolution in the USA, and find that in addition to the obvious factors, such as high p...

  11. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    Directory of Open Access Journals (Sweden)

    Jiin-Shuh Jean

    2008-01-01

    Full Text Available Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks. More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surface erosion. This paper suggests 17 antifreeze compounds potentially present in Martian seepage groundwater. Given their liquid state and physical properties, triethylene glycol, diethylene glycol, ethylene glycol, and 1,3-propylene glycol are advanced as the most likely candidate compounds. This paper also explores how a mixing of glycol or glycerol with salts in the Martian seepage groundwater may have lowered water¡¦s freezing point and raised its boiling point, with consequences that created fluid gully and channel erosion. Ethylene glycol and related hydrocarbon compounds have been identified in Martian and other interstellar meteorites. We suggest that these compounds and their proportions to water be included for detection in future explorations.

  12. Hydrocarbon anomaly in soil gas as near-surface expressions of upflows and outflows in geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Ong, H.L.; Higashihara, M.; Klusman, R.W.; Voorhees, K.J.; Pudjianto, R.; Ong, J

    1996-01-24

    A variety of hydrocarbons, C1 - C12, have been found in volcanic gases (fumarolic) and in geothermal waters and gases. The hydrocarbons are thought to have come from products of pyrolysis of kerogen in sedimentary rocks or they could be fed into the geothermal system by the recharging waters which may contain dissolved hydrocarbons or hydrocarbons extracted by the waters from the rocks. In the hot geothermal zone, 300°+ C, many of these hydrocarbons are in their critical state. It is thought that they move upwards due to buoyancy and flux up with the upflowing geothermal fluids in the upflow zones together with the magmatic gases. Permeability which could be provided by faults, fissures, mini and micro fractures are thought to provide pathways for the upward flux. A sensitive technique (Petrex) utilizing passive integrative adsorption of the hydrocarbons in soil gas on activated charcoal followed by desorption and analysis of the hydrocarbons by direct introduction mass spectrometry allows mapping of the anomalous areas. Surveys for geothermal resources conducted in Japan and in Indonesia show that the hydrocarbon anomaly occur over known fields and over areas strongly suspected of geothermal potential. The hydrocarbons found and identified were n-paraffins (C7-C9) and aromatics (C7-C8). Detection of permeable, i.e. active or open faults, parts of older faults which have been reactivated, e.g. by younger intersecting faults, and the area surrounding these faulted and permeable region is possible. The mechanism leading to the appearance of the hydrocarbon in the soil gas over upflow zones of the geothermal reservoir is proposed. The paraffins seems to be better pathfinders for the location of upflows than the aromatics. However the aromatics may, under certain circumstances, give better indications of the direction of the outflow of the geothermal system. It is thought that an upflow zone can be

  13. Can hydrocarbons entrapped in seep carbonates serve as gas geochemistry recorder?

    Science.gov (United States)

    Blumenberg, Martin; Pape, Thomas; Seifert, Richard; Bohrmann, Gerhard; Schlömer, Stefan

    2017-08-01

    The geochemistry of seep gases is useful for an understanding of the local petroleum system. Here it was tested whether individual light hydrocarbons in seep gases are representatively entrapped in authigenic carbonates that formed near active seep sites. If applicable, it would be possible to extract geochemical information not only on the origin but also on the thermal maturity of the hydrocarbon source rocks from the gases entrapped in carbonates in the past. Respective data could be used for a better understanding of paleoenvironments and might directly serve as calibration point for, amongst others, petroleum system modeling. For this approach, (sub)-recent seep carbonates from the Black Sea (Paleodnjepr region and Batumi seep area), two sites of the Campeche Knoll region in the Gulf of Mexico, and the Venere mud volcano (Mediterranean Sea) were selected. These seep carbonates derive from sites for which geochemical data on the currently seeping gases exist. During treatment with phosphoric acid, methane and higher hydrocarbons were released from all carbonates, but in low concentrations. Compositional studies demonstrate that the ratio of methane to the sum of higher hydrocarbons (C1/(C2+C3)) is (partly strongly) positively biased in the entrapped gas fraction. δ13C values of C1 were determined for all samples and, for the samples from the Gulf of Mexico and the Mediterranean Sea, also of C2 and C3. The present dataset from six seep sites indicates that information on the seeped methane can be—although with a scatter of several permil—recorded in seep carbonate matrices, but other valuable information like the composition and δ13C of ethane and propane appears to be modified or lost during, for example, enclosure or at an early stage of diagenesis.

  14. Natural gas conversion to higher hydrocarbons using plasma interactions with surfaces. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Kamath, V.A.; Morgan, B.L.; Airey, R.W.

    1993-12-01

    Experiments are reported in which a methane plasma is created, and the methyl ions and hydrogen ions are accelerated within a microchannel array so that they interact with neutral methane molecules on the inside surfaces of the microchannels. No catalysts are used, and the device operates at room temperature. Impact energies of the ions are in the range of 10 eV to greater than 100 eV, and the energy delivered in the interaction at the surfaces causes the production of larger hydrocarbon molecules, such as C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}, along with C{sub 3}, C{sub 4}, C{sub 5}m C{sub 6}, C{sub 7}m and C{sub 8} molecules. There is a decreasing percentage of larger molecules produced, in comparison with the C{sub 2} and C{sub 3} types. Conversion effectiveness is greater at higher pressure, due to the increased ionic activity. The yield of the higher hydrocarbons depends upon the external voltage used, and voltage can be used as a control parameter to adjust the output mixture proportions. A conversion energy of 2.59 kilowatt hours/killogram of output has been demonstrated, and a reduction of this by a factor of 10 is possible using known techniques. In batch experiments, the selectivity for C{sub 2} has varied from 47% to 88%, and selectivity for C{sub 6} has ranged from 0% to 12.8%. Other hydrocarbon selectivities also span a wide and useful range. The estimated costs for hydrocarbons produced with this technology are in the range of $200 per tonne, in production quantities, depending upon natural gas costs. Pilot production experiments are recommended to make these estimates more precise, and to address strategies for scaling the technology up to production levels. Applications are discussed.

  15. Gas chromatography-optical fiber detector for the speciation of aromatic hydrocarbons in confined areas.

    Science.gov (United States)

    Silva, Lurdes I B; Rocha-Santos, Teresa A P; Duarte, A C

    2008-08-01

    An analytical method, based on separation with gas chromatography (GC) and detection with optical fiber (OF), was used for the separation, detection and quantification of benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene. The use of OF as a detector is based on the variations of the reflected optical power detected when the aromatic compounds eluted from the GC column are sorbed in a thin polymeric film on a single-mode OF. General figures of merit, such as the analytical time, analytical error and analytical performance of GC-OF were similar to those of the classical analytical methods, such as a gas chromatography-flame ionization detector (GC-FID). However, the developed GC-OF method constitutes a much less expensive alternative for the speciation of aromatic hydrocarbons compounds, with high accuracy, and being most suitable for actual monitoring work on confined environments.

  16. Accumulation of polycyclic aromatic hydrocarbons by lichen transplants: Comparison with gas-phase passive air samplers.

    Science.gov (United States)

    Loppi, S; Pozo, K; Estellano, V H; Corsolini, S; Sardella, G; Paoli, L

    2015-09-01

    This study compared the accumulation of 16 polycyclic aromatic hydrocarbons (PAHs) in samples of the lichen Evernia prunastri exposed for 3 months in and around an industrial area of S Italy with that in co-located passive gas-phase air samplers. The results showed a strong linear correlations (R=0.96, P<0.05) between total PAHs in lichens and in passive samplers, clearly indicating that lichen transplants may provide direct quantitative information on the atmospheric load by total PAHs, allowing translation of lichen values into atmospheric concentrations. To the best of our knowledge this is the first study reporting such a correlation with gas-phase passive air samplers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Oil shale, shale oil, shale gas and non-conventional hydrocarbons

    Directory of Open Access Journals (Sweden)

    Clerici A.

    2015-01-01

    Full Text Available In recent years there has been a world “revolution” in the field of unconventional hydrocarbon reserves, which goes by the name of “shale gas”, gas contained inside clay sediments micropores. Shale gas finds particular development in the United States, which are now independent of imports and see a price reduction to less than one third of that in Europe. With the high oil prices, in addition to the non-conventional gas also “oil shales” (fine-grained sedimentary rocks that contain a large amount of organic material to be used both to be directly burned or to extract liquid fuels which go under the name of shale oil, extra heavy oils and bitumen are becoming an industrial reality. Both unconventional gas and oil reserves far exceed in the world the conventional oil and gas reserves, subverting the theory of fossil fuels scarcity. Values and location of these new fossil reserves in different countries and their production by comparison with conventional resources are presented. In view of the clear advantages of unconventional fossil resources, the potential environmental risks associated with their extraction and processing are also highlighted.

  18. Physical simulation on seepage features of commingled production and right time of production conversion for gas wells%气井多层合采渗流特征及接替生产物理模拟

    Institute of Scientific and Technical Information of China (English)

    谭玉涵; 郭京哲; 郑锋; 徐卫峰

    2015-01-01

    对于低孔、低渗气藏,为了提高单井产能和改善气田开发效益,许多生产井都采用了多层合采方式进行生产. 为了更真实地认识低渗气藏多层合采的渗流特征以及确定最佳合采接替时机,通过设计室内物理模拟实验,模拟气藏多层合采开发过程,研究了地层压力、渗透率及主控因素共同作用下的气藏渗流特征对开发效果的影响以及合采接替生产时机,认为多层合采时,高压、高渗层产量贡献率始终高于低压、低渗层;而对于低压、高渗层,实验初始阶段低压、高渗层的产量贡献率高于高压、低渗层,实验后期从主产气层变为次产气层;在不同的接替时机下,随着接替点压力的降低,采出程度呈现出降低的趋势;低渗层接替生产要比高渗层接替生产效果要好. 采用物理模拟实验研究多层合采产气渗流特征尚属新的尝试,其研究成果对制定类似气藏的合理开发技术策略提供了参考依据.%In order to increase single-well productivity and improve development economics of low porosity and low per-meability gas reservoirs ,many production wells adopt the way of commingled production .By laboratory physical experi-mental analysis ,the development process of commingled production was simulated to study the influences of seepage fea -tures of gas reservoir under the combined action of formation pressure ,permeability and the main controlling factors on the development effect ,and also the timing of production conversion .The results suggest that when commingled production is adopted in gas reservoirs ,the yield contribution rate of high pressure and high permeability layers is always higher than that of low pressure and low permeability layers;As for low pressure and high permeability layers ,their yield contribution rate is higher than that of high pressure and low permeability layers in the initial phase of the experiment ,and they turn from the primary gas

  19. Evidence for bacterially generated hydrocarbon gas in Canadian shield and fennoscandian shield rocks

    Science.gov (United States)

    Sherwood Lollar, B.; Frape, S. K.; Fritz, P.; Macko, S. A.; Welhan, J. A.; Blomqvist, R.; Lahermo, P. W.

    1993-12-01

    Hydrocarbon-rich gases found in crystalline rocks on the Canadian and Fennoscandian shields are isotopically and compositionally similar, suggesting that such gases are a characteristic feature of Precambrian Shield rocks. Gases occure in association with saline groundwaters and brines in pressurized "pockets" formed by sealed fracture systems within the host rocks. When released by drilling activities, gas pressures as high as 5000 kPa have been recorded. Typical gas flow rates for individual boreholes range from 0.25 L/min to 4 L/min. The highest concentrations of CH 4 are found in the deepest levels of the boreholes associated with CaNaCl (and NaCaCl) brines. N 2 is the second major component of the gases and with CH 4 accounts for up to 80 to >90 vol%. Higher hydrocarbon (C 2+) concentrations range from C2 = C3) ratios from 10-1000. Isotopically the gases show a wide range of values overall ( σ 13C = -57.5 to -41.1%; σ D = -245 to -470‰ ) but a relatively tight cluster of values within each sampling locality. The Enonkoski Mine methanes are unique with σ 13C values between -65.4 and -67.3‰ and σD values between -297 and -347‰. The shield gases are not readily reconcilable with conventional theories of methanogenesis. The range of C1/(C2 + C3) ratios for the shield gases is too low to be consistent with an entirely bacterial origin. In addition, σD CH 4 values are in general too depleted in the heavy isotope to be produced by thermogenic methanogenesis or by secondary alteration processes such as bacterial oxidation or migration. However, isotopic and compositional evidence indicates that bacterially derived gas can account for a significant component of the gas at all shield sites. Conventional bacterial gas accounts for 75-94 vol% of the occurrences at Enonkoski Mine in Finland. At each of the other shield sites, bacterial gas can account for up to 30-50 vol% of the total gas accumulation. This study and other recent evidence of active

  20. Emissions of Polycyclic Aromatic Hydrocarbons from Natural Gas Extraction into Air.

    Science.gov (United States)

    Paulik, L Blair; Donald, Carey E; Smith, Brian W; Tidwell, Lane G; Hobbie, Kevin A; Kincl, Laurel; Haynes, Erin N; Anderson, Kim A

    2016-07-19

    Natural gas extraction, often referred to as "fracking", has increased rapidly in the United States in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. Levels of benzo[a]pyrene, phenanthrene, and carcinogenic potency of PAH mixtures were highest when samplers were closest to active wells. PAH levels closest to natural gas activity were comparable to levels previously reported in rural areas in winter. Sourcing ratios indicated that PAHs were predominantly petrogenic, suggesting that PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. At sites closest to active wells, the risk estimated for maximum residential exposure was 0.04 in a million, which is below the U.S. Environmental Protection Agency's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest from them. This work suggests that natural gas extraction is contributing PAHs to the air, at levels that would not be expected to increase cancer risk.

  1. The binding nature of light hydrocarbons on Fe/MOF-74 for gas separation.

    Science.gov (United States)

    Kim, Heejin; Park, Joonho; Jung, Yousung

    2013-12-07

    The application of a metal-organic framework (MOF) has expanded into the area of heterogeneous catalysis, gas storage and separation, drug delivery, and lightweight magnets. Herein, we investigate the nature of olefin and paraffin binding on Fe/MOF-74 and identify several factors that determine separation efficiency using the first-principles calculations. The calculated binding energies and magnetic orderings are in excellent agreement with those observed in experiments. While the olefin strongly interacts with Fe atoms through a well-known π-complexation, the HOMO - 1(2) of the paraffin weakly interacts with Fe atoms without back-donation, facilitating the olefin-paraffin separation primarily. However, the mutual gas-gas interactions and magnetic transitions of the MOF host also contribute significantly to the total binding energy of each gas molecule as much as 2-28% and 6-8%, respectively, emphasizing the necessity that these subtle effects must be handled carefully when considering selective binding with small energy differences. In particular, Fe/MOF-74 is shown to be a unique system where the guest-dependent magnetic transition observed only for the olefin adsorption is a secondary reason for the high olefin-paraffin adsorption selectivity measured. The understanding of the hydrocarbon binding energetics can provide a way to modify MOFs for enhanced separation/sorption properties that can be complemented by principles of kinetic separation.

  2. Mineral oil in human tissues, part II: characterization of the accumulated hydrocarbons by comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Biedermann, Maurus; Barp, Laura; Kornauth, Christoph; Würger, Tanja; Rudas, Margaretha; Reiner, Angelika; Concin, Nicole; Grob, Koni

    2015-02-15

    Mineral oil hydrocarbons are by far the largest contaminant in the human body. Their composition differs from that in the mineral oils humans are exposed to, and varies also between different tissues of the same individual. Using the presently best technique for characterizing the composition of mineral oil hydrocarbons, comprehensive two-dimensional gas chromatography (GC×GC), the hydrocarbons in human tissues were compared to those of various mineral oils. This provided information about the strongly accumulated species and might give hints on the flow path through the human body. The selectivity of accumulation is probably also of interest for the risk assessment of synthetic hydrocarbons (polyolefins). GC×GC grouped the MOSH into classes of n-alkanes, paraffins with a low degree of branching, multibranched paraffins and naphthenes (alkylated cyclic hydrocarbons) with 1-4 rings. Metabolic elimination was observed for constituents of all these classes, but was selective within each class. The MOSH in the subcutaneous abdominal fat tissues and the mesenteric lymph nodes (MLN) had almost the same composition and included the distinct signals observed in mineral oil, though in reduced amounts relative to the cloud of unresolved hydrocarbons. The MOSH in the liver and the spleen were different from those in the MLN and fat tissue, but again with largely identical composition for a given individual. Virtually all constituents forming distinct signals were eliminated, leaving an unresolved residue of highly isomerized hydrocarbons.

  3. Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid-phase extraction coupled with gas chromatography and mass spectrometry.

    Science.gov (United States)

    Wang, Xianli; Kang, Haiyan; Wu, Junfeng

    2016-05-01

    Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid-phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid-phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0-1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015-0.591 and 0.045-1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1-monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m(-3) . 9,10-Dichloroanthracene and 1-monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water.

  4. Geologic seepage of methane and light alkanes in Los Angeles

    Science.gov (United States)

    Doezema, L. A.; Chang, K.; Baril, R.; Nwachuku, I.; Contreras, P.; Marquez, A.; Howard, D.

    2013-12-01

    Natural geologic seepage of methane from underground oil and natural gas reservoirs has been suggested to be an underreported part of the global methane budget. Other light alkanes are also given off in combination with the methane seepage, making it possible that geologic seepage is also a potentially significant global source of these light alkanes. This study reports C1-C5 findings from geologic seepage made in the Los Angeles region. Microseepage, invisible escape of gases, was measured primarily at Kenneth Hahn Regional Park, while macroseepage, the visible release of gases, was measured at the La Brea Tar Pits. Samples were collected using stainless steel canisters and flux chambers and were analyzed using gas chromatography with flame ionization detectors (GC-FID). Average microseepage flux rates of 0.95 μg m-2 h-1 for ethane and 0.51 μg m-2 h-1 were found for propane, while average macroseepage rates for methane, ethane, and propane were 664, 19.8, and 18.1 mg m-2 h-1 respectively. Relationships between microseepage flux rate and location of underground oil and natural deposit and earthquake fault lines are presented. Additionally, the relative importance of findings in context with global budgets and local air quality is discussed.

  5. Dynamics of the gas-liquid interfacial reaction of O(3P) atoms with hydrocarbons

    Science.gov (United States)

    Kelso, Hailey; Köhler, Sven P. K.; Henderson, David A.; McKendrick, Kenneth G.

    2003-11-01

    We describe an experimental approach to the determination of the nascent internal state distribution of gas-phase products of a gas-liquid interfacial reaction. The system chosen for study is O(3P) atoms with the surface of liquid deuterated squalane, a partially branched long-chain saturated hydrocarbon, C30D62. The nascent OD products are detected by laser-induced fluorescence. Both OD (v'=0) and (v'=1) were observed in significant yield. The rotational distributions in both vibrational levels are essentially the same, and are characteristic of a Boltzmann distribution at a temperature close to that of the liquid surface. This contrasts with the distributions in the corresponding homogeneous gas-phase reactions. We propose a preliminary interpretation in terms of a dominant trapping-desorption mechanism, in which the OD molecules are retained at the surface sufficiently long to cause rotational equilibration but not complete vibrational relaxation. The significant yield of vibrationally excited OD also suggests that the surface is not composed entirely of -CD3 endgroups, but that secondary and/or tertiary units along the backbone are exposed.

  6. Small hydrocarbon molecules in cloud-forming Brown Dwarf and giant gas planet atmospheres

    CERN Document Server

    Bilger, Camille; Helling, Christiane

    2013-01-01

    We study the abundances of complex carbon-bearing molecules in the oxygen-rich dust- forming atmospheres of Brown Dwarfs and giant gas planets. The inner atmospheric re- gions that form the inner boundary for thermochemical gas-phase models are investigated. Results from Drift-phoenix atmosphere simulations, which include the feedback of phase- non-equilibrium dust cloud formation on the atmospheric structure and the gas-phase abun- dances, are utilised. The resulting element depletion leads to a shift in the carbon-to-oxygen ratio such that several hydrocarbon molecules and cyanopolycyanopolyynene molecules can be present. An increase in surface gravity and/or a decrease in metallicity support the increase in the partial pressures of these species. CO, CO2, CH4, and HCN contain the largest fraction of carbon. In the upper atmosphere of low-metallicity objects, more carbon is contained in C4H than in CO, and also CH3 and C2H2 play an increasingly important role as carbon-sink. We determine chemical relaxation...

  7. Determination of solubility parameters and thermodynamic properties in hydrocarbon-solvent systems by gas chromatography

    Directory of Open Access Journals (Sweden)

    E. Díaz

    2007-06-01

    Full Text Available Gas chromatography used to calculate the specific retention volume of several hydrocarbons in different chromatographic liquid phases (Squalane, Carbowax-400, Carbowax-1500, Carbowax-4000, Amine-220, Dinonyl phthalate, Tributyl phosphate and Trixylenyl phosphate. Some thermodynamic parameters, such as enthalpy of sorption and Flory-Huggins parameters relating the interaction between liquid phases and solutes, were also calculated from the determined retention volumes. Liquid phase solubility parameters of Squalane, Carbowax-400, Carbowax-1500 and Carbowax-4000 at 80 ºC as well as the polar and apolar components were calculated too. A new model was proposed to correlate polar contribution to the solubility parameter of a liquid phase with the specific retention volume of a solute in this liquid phase.

  8. A Gas Chromatographic Analysis of Light Hydrocarbons on a Column Packed with Modified Silica Gel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A one-meter long column packed with silica gel is used to separate light hydrocarbons. The silica gel has been modified with several kinds of gas chromatography stationary phases. Among these, PEG 2000 shows fairly good effect when using 80-100 meshes silica gel for the separation of mixture of methane, ethane, ethylene, acetylene, propane, propylene and n-, i-butane. The different behavior of silica gel between batch to batch is also found. When silica gel is coated with a small amount of Al2O3 prepared with sol-gel method, better resolution has been observed on a 2-meter column compared with the non-modified silica gel.

  9. Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

    Science.gov (United States)

    Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

    2011-01-01

    A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x ). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

  10. Miniaturized Metal (Metal Alloy)/PdO(x)/SiC Hydrogen and Hydrocarbon Gas Sensors

    Science.gov (United States)

    Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

    2008-01-01

    A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

  11. Identification of polycyclic aromatic hydrocarbons in sugar cane soot by gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zamperlini, G.C.M.; Silva, M.R.S. [Instituto de Quimica de Araraquara UNESP, Aararaquara (Brazil). Dept. de Quimica Analitica; Vilegas, W. [Instituto de Quimica de Araraquara UNESP, Aararaquara (Brazil). Dept. de Quimica Organica

    1997-12-01

    Fly soot samples collected in the sugar cane fields after the process of burning were extracted in a Soxhlet apparatus (methylene chloride:methanol 4:1). The extracts were fractionated on silica gel Sep-Pak cartridges into three fractions. A gas chromatographic-mass spectrometric study of the fly soot extracts allowed the identification of the PAH with mutagenic and carcinogenic properties. Large amounts of aliphatic hydrocarbons, fatty acid esters and some PAHs were identified by GC-MS in full scan mode. GC-MS in the selective ion monitoring mode (SIM) was suitable for the determination of many PAHs, which are often present in the burnt biomass. 31 PAHs and 7 thiophens derivatives were identified. The presence of these compounds should be regraded as a caution to workers and the general population to avoid exposure to the fly soot. (orig.)

  12. Hydrocarbon degassing of the earth and origin of oil-gas fields (isotope-geochemical and geodynamic aspects)

    Science.gov (United States)

    Valyaev, Boris; Dremin, Ivan

    2016-04-01

    More than half a century ago, Academician PN Kropotkin substantiated the relationship of the formation and distribution of oil and gas fields with the processes of emanation hydrocarbon degassing of the Earth. Over the years, the concept of PN Kropotkin received further development and recognition of studies based on new factual material. Of particular importance are the following factors: a) the results of studies on global and regional uneven processes of traditional oil and gas and the role of deep faults in controlling the spread of oil and gas fields; b) the results of the research on gigantic volumes and localization of the discharges of hydrocarbon fluids (mud volcanoes, seeps) on land and into the atmosphere and through the bottom of the World ocean; c) the results of the studies on grand volumes of the spread of unconventional hydrocarbon resources in their non-traditional fields, especially on near-surface interval of unconventional oil and gas accumulation with gas hydrates, heavy oil and bitumen, as well as extraordinary resources of oil and gas in the shale and tight rocks. Deep mantle-crust nature of oil and gas in traditional and nontraditional deposits thus received further substantiation of geological and geophysical data and research results. However, isotopic and geochemical data are still interpreted in favor of the concept of the genesis of oil and gas in the processes of thermal catalytic conversion of organic matter of sedimentary rocks, at temperatures up to 200°C. In this report an alternative interpretation of the isotope carbon-hydrogen system (δ13C-δD) for gas and of oil deposits, isotope carbon system for methane and carbon dioxide (δ13C1-δ13C0) will be presented. An alternative interpretation will also be presented for the data on carbon-helium isotope geochemical system for oil and gas fields, volcanoes and mud volcanoes. These constructions agree with the geological data on the nature of deep hydrocarbon fluids involved in the

  13. Biomass consumption and CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire

    Science.gov (United States)

    T. G. Soares Neto; J. A. Carvalho; C. A. G. Veras; E. C. Alvarado; R. Gielow; E. N. Lincoln; T. J. Christian; R. J. Yokelson; J. C. Santos

    2009-01-01

    Biomass consumption and CO2, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48% and the estimated average moisture content of fresh biomass was 42% on...

  14. Aqueous extractive upgrading of bio-oils created by tail-gas reactive pyrolysis to produce pure hydrocarbons and phenols

    Science.gov (United States)

    Tail-gas reactive pyrolysis (TGRP) of biomass produces bio-oil that is lower in oxygen (~15 wt% total) and significantly more hydrocarbon-rich than traditional bio-oils or even catalytic fast pyrolysis. TGRP bio-oils lend themselves toward mild and inexpensive upgrading procedures. We isolated oxyge...

  15. A Study of the Migration and Accumulation Efficiency and the Genesis of Hydrocarbon Natural Gas in the Xujiaweizi Fault Depression

    Institute of Scientific and Technical Information of China (English)

    LI Jijun; LU Shuangfang; XUE Haitao; HUO Qiuli; XU Qingxia

    2008-01-01

    In order to investigate the migration and accumulation efficiency of hydrocarbon natural gas in the Xujiaweizi fault depression, and to provide new evidence for the classification of its genesis, a source rock pyrolysis experiment in a closed system was designed and carried out. Based on this, kinetic models for describing gas generation from organic matter and carbon isotope fractionation during this process were established, calibrated and then extrapolated to geologic conditions by combining the thermal history data of the Xushen-1 Well. The results indicate that the coal measures in the Xujiaweizi fault depression are typical "high-efficiency gas sources", the natural gas generated from them has a high migration and accumulation efficiency, and consequently a large-scale natural gas accumulation occurred in the area. The highly/over matured coal measures in the Xujiaweizi fault depression generate coaliferons gas with a high δ13C1 value (> -20‰) at the late stage, making the carbon isotope composition of organic alkane gases abnormally heavy. In addition, the mixing and dissipation through the caprock of natural gas can result in the negative carbon isotope sequence (δ13C1 >δ13C2 >δ13C3 >δ13C4) of organic alkane gases, and the dissipation can also lead to the abnormally heavy carbon isotope composition of organic alkane gases. As for the discovery of inorganic nonhydrocarbon gas reservoirs, it can only serve as an accessorial evidence rather than a direct evidence that the hydrocarbon gas is inorganic. As a result, it needs stronger evidence to classify the hydrocarbon natural gas in the Xujiaweizi fault depression as inorganic gas.

  16. Oil and gas potential assessment for coal measure source rocks on absolute concentration of n-alkanes and aromatic hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Absolute concentration of normal alkanes(n-alkanes) and aromatic hydrocarbons in bitumen extracted from source rocks in the period of thermodegradation from Turpan-Hami Basin suggests that aromatic hydrocarbons are dominant in coal and carbargilite while n-alkanes are dominant in mudstones. Bulkrock analysis and gas chromatograph/mass spectrum(GC-MS) of source rocks shows aromatic hydrocarbons are dominant in total ion chromatograms(TIC) of samples with poor perhydrous macerals while n-alkanes are dominant in TICs of samples with abundant perhydrous macerals. The identification of oil-prone and gas prone property based on GC-MS of bitumen "A" together with bulkrock analysis indicates that source rocks from Shengbei area are more oil-prone while source rocks from Qiudong and Xiaocaohu areas are more gas-prone,coinciding with the distribution of oil and gas reservoirs in Taibei Sag. Ratios used to identify oil-prone and gas-prone property for source rocks from Turpan Basin are proposed:n-alkanes >110 μg·mg-1,aromatics <15 μg·mg-1,and n-alkanes/aromatics >8 for oil-prone source rock bitumen while n-alkanes<82 μg·mg-1,aromatics >40 μg·mg-1,and n-alkanes/aromatics <1.5 for gas-prone source rock bitumen.

  17. High-resolution gas chromatographic analysis of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons; Separacion por cromatografia de gases de alta eficiencia de hidrocarburos aromaticos policiclicos, (PAH) y alifaticos (AH) ambientales, empleado como fases estacionarias OV-1 y SE-54

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Gonzalez, D.

    1988-07-01

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons and aliphatic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column in two different polar stationary phases OV-1 and SE-54. The limitation and the advantages of the procedure are discussed in terms of separation, sensitivity and precision. (Author) 20 refs.

  18. Unravelling the impact of hydrocarbon structure on the fumarate addition mechanism--a gas-phase ab initio study.

    Science.gov (United States)

    Bharadwaj, Vivek S; Vyas, Shubham; Villano, Stephanie M; Maupin, C Mark; Dean, Anthony M

    2015-02-14

    The fumarate addition reaction mechanism is central to the anaerobic biodegradation pathway of various hydrocarbons, both aromatic (e.g., toluene, ethyl benzene) and aliphatic (e.g., n-hexane, dodecane). Succinate synthase enzymes, which belong to the glycyl radical enzyme family, are the main facilitators of these biochemical reactions. The overall catalytic mechanism that converts hydrocarbons to a succinate molecule involves three steps: (1) initial H-abstraction from the hydrocarbon by the radical enzyme, (2) addition of the resulting hydrocarbon radical to fumarate, and (3) hydrogen abstraction by the addition product to regenerate the radical enzyme. Since the biodegradation of hydrocarbon fuels via the fumarate addition mechanism is linked to bio-corrosion, an improved understanding of this reaction is imperative to our efforts of predicting the susceptibility of proposed alternative fuels to biodegradation. An improved understanding of the fuel biodegradation process also has the potential to benefit bioremediation. In this study, we consider model aromatic (toluene) and aliphatic (butane) compounds to evaluate the impact of hydrocarbon structure on the energetics and kinetics of the fumarate addition mechanism by means of high level ab initio gas-phase calculations. We predict that the rate of toluene degradation is ∼100 times faster than butane at 298 K, and that the first abstraction step is kinetically significant for both hydrocarbons, which is consistent with deuterium isotope effect studies on toluene degradation. The detailed computations also show that the predicted stereo-chemical preference of the succinate products for both toluene and butane are due to the differences in the radical addition rate constants for the various isomers. The computational and kinetic modeling work presented here demonstrates the importance of considering pre-reaction and product complexes in order to accurately treat gas phase systems that involve intra and inter

  19. Distribution and geological control of mud volcanoes and other fluid/free gas seepage features in the Mediterranean Sea and nearby Gulf of Cadiz

    Science.gov (United States)

    Mascle, Jean; Mary, Flore; Praeg, Daniel; Brosolo, Laetitia; Camera, Laurent; Ceramicola, Silvia; Dupré, Stéphanie

    2014-06-01

    Existing knowledge on the distribution of mud volcanoes (MVs) and other significant fluid/free gas-venting features (mud cones, mud pies, mud-brine pools, mud carbonate cones, gas chimneys and, in some cases, pockmark fields) discovered on the seafloor of the Mediterranean Sea and in the nearby Gulf of Cadiz has been compiled using regional geophysical information (including multibeam coverage of most deepwater areas). The resulting dataset comprises both features proven from geological sampling, or in situ observations, and many previously unrecognized MVs inferred from geophysical evidence. The synthesis reveals that MVs clearly have non-random distributions that correspond to two main geodynamic settings: (1) the vast majority occur along the various tectono-sedimentary accretionary wedges of the Africa-Eurasia subduction zone, particularly in the central and eastern Mediterranean basins (external Calabrian Arc, Mediterranean Ridge, Florence Rise) but also along its westernmost boundary in the Gulf of Cadiz; (2) other MVs characterize thick depocentres along parts of the Mesozoic passive continental margins that border Africa from eastern Tunisia to the Levantine coasts, particularly off Egypt and, locally, within some areas of the western Mediterranean back-arc basins. Meaningfully accounting for MV distribution necessitates evidence of overpressured fluids and mud-rich layers. In addition, cross-correlations between MVs and other GIS-based data, such as maps of the Messinian evaporite basins and/or active (or recently active) tectonic trends, stress the importance of assessing geological control in terms of the presence, or not, of thick seals and potential conduits. It is contended that new MV discoveries may be expected in the study region, particularly along the southern Ionian Sea continental margins.

  20. Polycyclic aromatic hydrocarbon ionization as a tracer of gas flows through protoplanetary disk gaps

    CERN Document Server

    Maaskant, K M; Waters, L B F M; Tielens, A G G M

    2014-01-01

    Planet-forming disks of gas and dust around young stars contain polycyclic aromatic hydrocarbons (PAHs). We aim to characterize how the charge state of PAHs can be used as a probe of flows of gas through protoplanetary gaps. In this context, our goal is to understand the PAH spectra of four transitional disks. In addition, we want to explain the observed correlation between PAH ionization (traced by the 6.2/11.3 feature ratio) and the disk mass (traced by the 1.3 mm luminosity). We implement a model to calculate the charge state of PAHs in the radiative transfer code MCMax. The emission spectra and ionization balance are calculated. A benchmark modeling grid is presented that shows how PAH ionization and luminosity behave as a function of star and disk properties. The PAH ionization is most sensitive to ultraviolet (UV) radiation and the electron density. In optically thick disks, where the UV field is low and the electron density is high, PAHs are predominantly neutral. Ionized PAHs trace low-density optical...

  1. Process and apparatus for conversion of water vapor with coal or hydrocarbon into a product gas

    Energy Technology Data Exchange (ETDEWEB)

    Weirich, W.; Barnert, H.; Oertel, M.; Schulten, R.

    1990-03-27

    A process and apparatus are provided for conversion of steam and hydrocarbon, or steam and coal, into a product gas which contains hydrogen. The conversion rate is augmented by effective extraction and removal of hydrogen as and when hydrogen is generated. Within a reaction vessel wherein the conversion takes place, a chamber for collection of hydrogen is formed by the provision of a hydrogen permeable membrane. The chamber is provided with a hydrogen extraction means and houses a support structure, for example, in the form of a mesh providing structural support to the membrane. The membrane may be of a pleated or corrugated construction, so as to provide an enlarged surface for the membrane to facilitate hydrogen extraction. Also, to further facilitate hydrogen extraction, a hydrogen partial pressure differential is maintained across the membrane, such as, for example, by the counter pressure of an inert gas. A preferred configuration for the apparatus of the invention is a tubular construction which houses generally tubular hydrogen extraction chambers. 5 figs.

  2. Solid-phase microextraction-gas chromatographic determination of volatile monoaromatic hydrocarbons in soil.

    Science.gov (United States)

    Zygmunt, B; Namiesnik, J

    2001-08-01

    Benzene, toluene, ethylbenzene, three isomers of xylene, and cumene have been isolated and enriched from soil samples by a combination of water extraction at room and elevated temperature and headspace-solid-phase microextraction before their gas chromatographic-mass spectrometric (GC-MS) determination. The conditions used for all stages of sample preparation and chromatographic analysis were optimized. Analytes sampled on a polydimethylsiloxane-coated solid-phase microextraction fiber were thermally desorbed in the split/splitless injector of a gas chromatograph (GC) coupled with a mass spectrometer (MS). The desorption temperature was optimized. The GC separation was performed in a capillary column. Detection limits were found to be of the order of ca. 1 ng g(-1). Relative recoveries of the analytes from soils were found to be highly dependent on soil organic-matter content and on compound identity; they ranged from ca 92 to 96% for sandy soil (extraction at room temperature) and from ca 27 to 55% for peaty soil (extraction at elevated temperature). A few real-world soil samples were analyzed; the individual monoaromatic hydrocarbon content ranged from below detection limits to 6.4 ng g(-1) for benzene and 8.1 for the total of p- + m-xylene.

  3. Hydrocarbons peaks at Weybourne: What role do natural gas emissions play in the regional background?

    Science.gov (United States)

    Jacob, M. J.; Fleming, Z. L.; Monks, P. S.; Hulse, A.; Oram, D.; Bandy, B. J.; Penkett, S. A.; Hamilton, J. F.; Hopkins, J. R.

    2009-04-01

    Detailed chemical measurements were carried out during the TORCH II (Tropospheric ORganic CHemistry Experiment) campaign at the Weybourne Atmospheric Observatory on the north coast of Norfolk, UK in May 2004. On a number of occasions, large short-lived concentrations of alkenes were observed that correlated with CO, acetaldehyde, HCHO and some alkanes. Foremost was propene, which indicated to have come from emissions from oil and natural gas industries in the North Sea. Simultaneously, a sharp increase in peroxy radicals was observed (from ozone alkene reactions that also produced secondary species such as alkyl nitrates) and subsequent ozone destruction. These emission events were marked by O3 reduction with no corresponding NOy peaks but with extremely high levels of alkene and alkyl nitrates, implying the formation of large levels of peroxy radicals, leading to oxidation consequences in this clean marine environment. Steady state modelling to calculate OH and RO2 values during the episodes revealed that the only source of such high OH and ROx was the ozonolysis of propene. An air mass origin study linked the hydrocarbon peaks with northerly air masses, over the path of known North Sea oil and gas fields. Analysis of VOC measurements at Weybourne during the past 15 years reveals the frequency of such VOC spikes and the impact they could have on photochemical ozone production when they to occur during the daytime and ozone-alkene reactions at nighttime.

  4. Estimation of the minimum and maximum substrate temperatures for diamond growth from hydrogen-hydrocarbon gas mixtures

    Science.gov (United States)

    Zhang, Yafei; Zhang, Fangqing; Chen, Guanghua

    1994-12-01

    It is proposed in this paper that the minimum substrate temperature for diamond growth from hydrogen-hydrocarbon gas mixtures be determined by the packing arrangements of hydrocarbon fragments at the surface, and the maximum substrate temperature be limited by the diamond growth surface reconstruction, which can be prevented by saturating the surface dangling bonds with atomic hydrogen. Theoretical calculations have been done by a formula proposed by Dryburgh [J. Crystal Growth 130 (1993) 305], and the results show that diamond can be deposited at the substrate temperatures ranging from ≈ 400 to ≈ 1200°C by low pressure chemical vapor deposition. This is consistent with experimental observations.

  5. Hydrocarbon gas standards at the pmol/mol level to support ambient atmospheric measurements.

    Science.gov (United States)

    Rhoderick, George C; Duewer, David L; Ning, Li; DeSirant, Kathryn

    2010-02-01

    Studies of climate change increasingly recognize the diverse influences exerted by hydrocarbons in the atmosphere, including roles in particulates and ozone formation. Measurements of key non-methane hydrocarbons (NMHCs) suggest atmospheric concentrations ranging from low pmol/mol to nmol/mol, depending on location and compound. To accurately establish concentration trends and to relate measurement records from many laboratories and researchers, it is essential to have good calibration standards. Several of the world's National Metrology Institutes (NMIs) are developing primary and secondary reference gas standards at the nmol/mol level. While the U.S. NMI, the National Institute of Standards and Technology (NIST), has developed pmol/mol standards for halocarbons and some volatile organics, the feasibility of preparing well-characterized, stable standards for NMHCs at the pmol/mol level is not yet established. NIST recently developed a suite of primary standards by gravimetric dilution that contains 18 NMHCs covering the concentration range of 60 pmol/mol to 230 pmol/mol. Taking into account the small but chemically significant contribution of NMHCs in the high-purity diluent nitrogen used in their preparation, the relative concentrations and short-term stability (2 to 3 months) of these NMHCs in the primary standards have been confirmed by chromatographic analysis. The gravimetric values assigned from the methods used to prepare the materials and the analytical concentrations determined from chromatographic analysis generally agree to within +/-2 pmol/mol. However, anomalous results for several of the compounds reflect the difficulties inherent in avoiding contamination and making accurate measurements at these very low levels.

  6. Lifecycle analysis of renewable natural gas and hydrocarbon fuels from wastewater treatment plants’ sludge

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Uisung [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Urgun Demirtas, Meltem [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Tao, Ling [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    Wastewater treatment plants (WWTPs) produce sludge as a byproduct when they treat wastewater. In the United States, over 8 million dry tons of sludge are produced annually just from publicly owned WWTPs. Sludge is commonly treated in anaerobic digesters, which generate biogas; the biogas is then largely flared to reduce emissions of methane, a potent greenhouse gas. Because sludge is quite homogeneous and has a high energy content, it is a good potential feedstock for other conversion processes that make biofuels, bioproducts, and power. For example, biogas from anaerobic digesters can be used to generate renewable natural gas (RNG), which can be further processed to produce compressed natural gas (CNG) and liquefied natural gas (LNG). Sludge can be directly converted into hydrocarbon liquid fuels via thermochemical processes such as hydrothermal liquefaction (HTL). Currently, the environmental impacts of converting sludge into energy are largely unknown, and only a few studies have focused on the environmental impacts of RNG produced from existing anaerobic digesters. As biofuels from sludge generate high interest, however, existing anaerobic digesters could be upgraded to technology with more economic potential and more environmental benefits. The environmental impacts of using a different anaerobic digestion (AD) technology to convert sludge into energy have yet to be analyzed. In addition, no studies are available about the direct conversion of sludge into liquid fuels. In order to estimate the energy consumption and greenhouse gas (GHG) emissions impacts of these alternative pathways (sludge-to-RNG and sludge-to-liquid), this study performed a lifecycle analysis (LCA) using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. The energy uses and GHG emissions associated with the RNG and hydrocarbon liquid are analyzed relative to the current typical sludge management case, which consists of a single-stage mesophilic

  7. Gas hydrate distribution and hydrocarbon maturation north of the Knipovich Ridge, western Svalbard margin

    Science.gov (United States)

    Dumke, Ines; Burwicz, Ewa B.; Berndt, Christian; Klaeschen, Dirk; Feseker, Tomas; Geissler, Wolfram H.; Sarkar, Sudipta

    2016-03-01

    A bottom-simulating reflector (BSR) occurs west of Svalbard in water depths exceeding 600 m, indicating that gas hydrate occurrence in marine sediments is more widespread in this region than anywhere else on the eastern North Atlantic margin. Regional BSR mapping shows the presence of hydrate and free gas in several areas, with the largest area located north of the Knipovich Ridge, a slow spreading ridge segment of the Mid Atlantic Ridge system. Here heat flow is high (up to 330 mW m-2), increasing toward the ridge axis. The coinciding maxima in across-margin BSR width and heat flow suggest that the Knipovich Ridge influenced methane generation in this area. This is supported by recent finds of thermogenic methane at cold seeps north of the ridge termination. To evaluate the source rock potential on the western Svalbard margin, we applied 1-D petroleum system modeling at three sites. The modeling shows that temperature and burial conditions near the ridge were sufficient to produce hydrocarbons. The bulk petroleum mass produced since the Eocene is at least 5 kt and could be as high as ~0.2 Mt. Most likely, source rocks are Miocene organic-rich sediments and a potential Eocene source rock that may exist in the area if early rifting created sufficiently deep depocenters. Thermogenic methane production could thus explain the more widespread presence of gas hydrates north of the Knipovich Ridge. The presence of microbial methane on the upper continental slope and shelf indicates that the origin of methane on the Svalbard margin varies spatially.

  8. STABILITY ANALYSIS OF RIVERBANK SUBJECT TO SEEPAGE

    Institute of Scientific and Technical Information of China (English)

    Yan LU; Yongjun LU; Xingnong ZHANG

    2007-01-01

    The stability of riverbanks subject to seepage is studied experimentally and theoretically in this paper. By including seepage in a 3-dimensional theoretical analysis, the study first shows how the critical slope or angle of repose of a cohesionless material is related to the ratio of the hydraulic gradient of seepage to its critical value under the fluidization condition. The critical stable slope is shown to be related to not only the hydraulic gradient but also the seepage direction. Measured laboratory data reasonably fit well with the theoretical relationship for the case of injection and suction. The data reveal that the slope is reduced with injection and increased with suction, respectively. Additionally, the study identifies the seepage direction which results in a minimum critical stable slope for a certain hydraulic gradient of seepage.

  9. Geochemical Features of Shale Hydrocarbons of the Central Part of Volga-Ural Oil and Gas Province

    Science.gov (United States)

    Nosova, Fidania F.; Pronin, Nikita V.; Plotnikova, Irina N.; Nosova, Julia G.

    2014-05-01

    This report contains the results of the studies of shale hydrocarbons from carbonate-siliceous rocks on the territory of South-Tatar arch of Volga-Ural oil and gas province of the East European Platform. The assessment of the prospects of shale hydrocarbon in Tatarstan primarily involves finding of low permeable, poor-porous shale strata that would be rich in organic matter. Basing on the analysis of the geological structure of the sedimentary cover, we can distinguish three main objects that can be considered as promising targets for the study from the point of the possible presence of shale hydrocarbons: sedimentary deposits Riphean- Vendian; Domanicoid high-carbon rocks of Devonian time; sedimentary strata in central and side areas of Kama-Kinel deflection system. The main object of this study is Domanicoid high-carbon rocks of Devonian time. They are mainly represented by dark gray, almost black bituminous limestones that are interbedded with calcareous siliceous shales and cherts. Complex studies include the following: extraction of bitumen from the rock, determination of organic carbon content, determination of the group and elemental composition of the bitumen, gas chromatographic studies of the alkanoic lube fractions of bitumoid and oil, gas chromato-mass spectrometry of the naphthenic lube fractions of bitumoid and oil, pyrolysis studies of the rock using the Rock -Eval method (before and after extraction), study of trace-element composition of the rocks and petrologen, comparison in terms of adsorbed gas and studying of the composition of adsorbed gases. Group and elemental analyses showed that hydrocarbons scattered in the samples contain mainly resinous- and asphaltene components, the share lube fraction is smaller. The terms sediment genesis changed from weakly to strongly reducing. According to the results of gas chromatography, no biodegradation processes were observed. According to biomarker indicators in the samples studied there is some certain

  10. Mid- Atlantic Gas Hydrate, Heat Flow, and Basin Analysis: Implications to Hydrocarbon Production in the Carolina Trough

    Science.gov (United States)

    Phrampus, B. J.

    2015-12-01

    The new Mid- and South Atlantic Planning Areas for oil and gas leasing is proposed to open in 2021. This region lacks in contemporary geologic and geophysical petroleum data and has no conventional wells drilled within the proposed leasing area. As such, addressing the hydrocarbon potential of this region is particularly difficult. Here, we use new and legacy multi-channel seismic data with heat flow observations, ocean temperature measurements, and new seismic interpretations of gas hydrate deposits to determine basin-wide heat flow along the Mid- Atlantic. These data reveal a conductive heat flow regime along the continental margin with a lack of fluid flow that is consistent with sea floor spreading rates and cooling oceanic crust. We then use these observations in combination with basal heat flow models and sedimentation records to determine the thermal history of a cross section of the Carolina Trough. These models reveal varying depth of potential hydrocarbon production that begin at ~ 2000 mbsf and extend down to depths greater than 7000 mbsf across the Carolina Trough. These potentially productive depths correspond to varying stratal ages, but all models contain the Late Jurassic, which is a potential analog to the U.S. Gulf Coast's Smackover Formation. Additionally, the timing of hydrocarbon generation reveal that Early through Middle Jurassic evaporite deposits and Late Jurassic tight limestones should have been in place before the Early Jurassic source rocks reached a depth of burial sufficiently deep for the production of hydrocarbons. These potential seals may trap significant quantities of hydrocarbons with in the Jurassic layers, resulting in significant hydrocarbon potential within the Carolina Trough.

  11. C-C stretching Raman spectra and stabilities of hydrocarbon molecules in natural gas hydrates: a quantum chemical study.

    Science.gov (United States)

    Liu, Yuan; Ojamäe, Lars

    2014-12-11

    The presence of specific hydrocarbon gas molecules in various types of water cavities in natural gas hydrates (NGHs) are governed by the relative stabilities of these encapsulated guest molecule-water cavity combinations. Using molecular quantum chemical dispersion-corrected hybrid density functional computations, the interaction (ΔE(host--guest)) and cohesive energies (ΔE(coh)), enthalpies, and Gibbs free energies for the complexes of host water cages and hydrocarbon guest molecules are calculated at the ωB97X-D/6-311++G(2d,2p) level of theory. The zero-point energy effect of ΔE(host-guest) and ΔE(coh) is found to be quite substantial. The energetically optimal host-guest combinations for seven hydrocarbon gas molecules (CH4, C2H6, C3H6, C3H8, C4H8, i-C4H10, and n-C4H10) and various water cavities (D, ID, T, P, H, and I) in NGHs are found to be CH4@D, C2H6@T, C3H6@T, C3H8@T, C4H8@T/P/H, i-C4H10@H, and n-C4H10@H, as the largest cohesive energy magnitudes will be obtained with these host-guest combinations. The stabilities of various water cavities enclosing hydrocarbon molecules are evaluated from the computed cohesive Gibbs free energies: CH4 prefers to be trapped in a ID cage; C2H6 prefer T cages; C3H6 and C3H8 prefer T and H cages; C4H8 and i-C4H10 prefer H cages; and n-C4H10 prefer I cages. The vibrational frequencies and Raman intensities of the C-C stretching vibrational modes for these seven hydrocarbon molecules enclosed in each water cavity are computed. A blue shift results after the guest molecule is trapped from gas phase into various water cages due to the host-guest interactions between the water cage and hydrocarbon molecule. The frequency shifts to the red as the radius of water cages increases. The model calculations support the view that C-C stretching vibrations of hydrocarbon molecules in the water cavities can be used as a tool to identify the types of crystal phases and guest molecules in NGHs.

  12. A seepage erosion sediment transport function and geometric headcut relationships for predicting seepage erosion undercutting

    Science.gov (United States)

    Seepage erosion is an important factor in hillslope instability and failure. However, predicting erosion by subsurface flow or seepage and incorporating its effects into stability models remain a challenge. Limitations exist with all existing seepage erosion sediment transport functions, including n...

  13. Improved Resolution of Hydrocarbon Structures and Constitutional Isomers in Complex Mixtures Using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Isaacman, Gabriel [Univ. of California, Berkeley, CA (United States); Wilson, Kevin R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chan, Arthur W. H. [Univ. of California, Berkeley, CA (United States); Worton, David R. [Univ. of California, Berkeley, CA (United States). Aerosol Dynamics Inc., Berkeley, CA (United States); Kimmel, Joel R. [Aerodyne Research, Inc., Billerica, MA (United States); Univ. of Colorado, Boulder, CO (United States). Tofwerk AG, Thun (Switzerland); Nah, Theodora [Univ. of California, Berkeley, CA (United States); Hohaus, Thorsten [Aerodyne Research, Inc., Billerica, MA (United States); Gonin, Marc [Tofwerk AG, Thun (Switzerland); Kroll, Jesse H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Worsnop, Douglas R. [Aerodyne Research, Inc., Billerica, MA (United States); Goldstein, Allen H. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-01-30

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography/mass spectrometry (GC/MS) techniques. In this study, we use vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally “unresolved complex mixture” by separating components by GC retention time, tR, and mass-to-charge ratio, m/z, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved on the basis of tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. Lastly, the classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  14. In-situ and on-line measurement of gas flux at a hydrocarbon seep from the northern South China Sea

    Science.gov (United States)

    Di, Pengfei; Feng, Dong; Chen, Duofu

    2014-06-01

    Natural hydrocarbon seeps in the marine environment are important sources of methane and other greenhouse gases to the ocean and the atmosphere. Accurate quantification of methane flux at hydrocarbon seeps is therefore necessary to evaluate their influence on the global methane budget and climate change. Hydrocarbon seeps on the seabed produce a near-shore gas bubble zone along the shallow western coast of Hainan Island, northern South China Sea. An in-situ and on-line gas flux measuring device was deployed over a hydrocarbon seep to quantify the gas flux by equal volume exchange venting from the seabed offshore of Ledong Town, Hainan Island, over 19 days. The physiochemical parameters and the dissolved methane concentration of the bottom water at the hydrocarbon seep were also measured. The gas flux from the hydrocarbon seep varied from 22 to 77 l/day with the tidal period and was strongly negatively correlated with water depth. The flux data from the seep suggests that the variation in hydrostatic pressure induced by tidal forcing and ocean swell may control the variation of the gas flux. The bottom water dissolved methane concentration, ranging from 26 to 74 nmol/L, was negatively correlated with temperature and water depth at the seabed and positively with the gas flux. The total gas volume released from the hydrocarbon seep was 30.5 m3 for the 19-day period, providing an estimated gas flux of 600 m3/yr. The 120 known hydrocarbon seeps along the eastern edge of the Yinggehai Basin could vent a large quantity of methane from the seafloor, which suggests that hydrocarbon seeps on the continental margin of the northern South China Sea may be an important natural source of methane to the atmosphere.

  15. Comprehensive database of Manufactured Gas Plant tars. Part C. Heterocyclic and hydroxylated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Gallacher, Christopher; Thomas, Russell; Lord, Richard; Kalin, Robert M; Taylor, Chris

    2017-08-15

    Coal tars are a mixture of organic and inorganic compounds that were by-products from the manufactured gas and coke making industries. The tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found in different tar types is of value to understand both how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present in a database produced from 16 different tars from five different production processes. Samples of coal tar were extracted using accelerated solvent extraction (ASE) and derivatized post-extraction using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). The derivatized samples were analysed using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS). A total of 865 heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons (PAHs) were detected in 16 tar samples produced by five different processes. The contents of both heterocyclic and hydroxylated PAHs varied greatly with the production process used, with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not have been be detected without the use of derivatization. Coal tars produced using different production processes and feedstocks yielded tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important analytical information that would otherwise not have been obtained without the use of derivatization and GCxGC/TOFMS. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Polycyclic aromatic hydrocarbon emissions from the combustion of alternative fuels in a gas turbine engine.

    Science.gov (United States)

    Christie, Simon; Raper, David; Lee, David S; Williams, Paul I; Rye, Lucas; Blakey, Simon; Wilson, Chris W; Lobo, Prem; Hagen, Donald; Whitefield, Philip D

    2012-06-01

    We report on the particulate-bound polycyclic aromatic hydrocarbons (PAH) in the exhaust of a test-bed gas turbine engine when powered by Jet A-1 aviation fuel and a number of alternative fuels: Sasol fully synthetic jet fuel (FSJF), Shell gas-to-liquid (GTL) kerosene, and Jet A-1/GTL 50:50 blended kerosene. The concentration of PAH compounds in the exhaust emissions vary greatly between fuels. Combustion of FSJF produces the greatest total concentration of PAH compounds while combustion of GTL produces the least. However, when PAHs in the exhaust sample are measured in terms of the regulatory marker compound benzo[a]pyrene, then all of the alternative fuels emit a lower concentration of PAH in comparison to Jet A-1. Emissions from the combustion of Jet A-1/GTL blended kerosene were found to have a disproportionately low concentration of PAHs and appear to inherit a greater proportion of the GTL emission characteristics than would be expected from volume fraction alone. The data imply the presence of a nonlinear relation between fuel blend composition and the emission of PAH compounds. For each of the fuels, the speciation of PAH compounds present in the exhaust emissions were found to be remarkably similar (R(2) = 0.94-0.62), and the results do provide evidence to support the premise that PAH speciation is to some extent indicative of the emission source. In contrast, no correlation was found between the PAH species present in the fuel with those subsequently emitted in the exhaust. The results strongly suggests that local air quality measured in terms of the particulate-bound PAH burden could be significantly improved by the use of GTL kerosene either blended with or in place of Jet A-1 kerosene.

  17. Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California

    Science.gov (United States)

    Lorenson, T.D.; Wong, Florence L.; Dartnell, Peter; Sliter, Ray W.

    2014-01-01

    Significant offshore asphaltic deposits with active seepage occur in the Santa Barbara Channel offshore southern California. The composition and isotopic signatures of gases sampled from the oil and gas seeps reveal that the coexisting oil in the shallow subsurface is anaerobically biodegraded, generating CO2 with secondary CH4 production. Biomineralization can result in the consumption of as much as 60% by weight of the original oil, with 13C enrichment of CO2. Analyses of gas emitted from asphaltic accumulations or seeps on the seafloor indicate up to 11% CO2 with 13C enrichment reaching +24.8‰. Methane concentrations range from less than 30% up to 98% with isotopic compositions of –34.9 to –66.1‰. Higher molecular weight hydrocarbon gases are present in strongly varying concentrations reflecting both oil-associated gas and biodegradation; propane is preferentially biodegraded, resulting in an enriched 13C isotopic composition as enriched as –19.5‰. Assuming the 132 million barrels of asphaltic residues on the seafloor represent ~40% of the original oil volume and mass, the estimated gas generated is 5.0×1010 kg (~76×109 m3) CH4 and/or 1.4×1011 kg CO2 over the lifetime of seepage needed to produce the volume of these deposits. Geologic relationships and oil weathering inferences suggest the deposits are of early Holocene age or even younger. Assuming an age of ~1,000 years, annual fluxes are on the order of 5.0×107 kg (~76×106 m3) and/or 1.4×108 kg for CH4 and CO2, respectively. The daily volumetric emission rate (2.1×105 m3) is comparable to current CH4 emission from Coal Oil Point seeps (1.5×105 m3/day), and may be a significant source of both CH4 and CO2 to the atmosphere provided that the gas can be transported through the water column.

  18. Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California

    Science.gov (United States)

    Lorenson, Thomas D.; Wong, Florence L.; Dartnell, Peter; Sliter, Ray W.

    2014-06-01

    Significant offshore asphaltic deposits with active seepage occur in the Santa Barbara Channel offshore southern California. The composition and isotopic signatures of gases sampled from the oil and gas seeps reveal that the coexisting oil in the shallow subsurface is anaerobically biodegraded, generating CO2 with secondary CH4 production. Biomineralization can result in the consumption of as much as 60% by weight of the original oil, with 13C enrichment of CO2. Analyses of gas emitted from asphaltic accumulations or seeps on the seafloor indicate up to 11% CO2 with 13C enrichment reaching +24.8‰. Methane concentrations range from less than 30% up to 98% with isotopic compositions of -34.9 to -66.1‰. Higher molecular weight hydrocarbon gases are present in strongly varying concentrations reflecting both oil-associated gas and biodegradation; propane is preferentially biodegraded, resulting in an enriched 13C isotopic composition as enriched as -19.5‰. Assuming the 132 million barrels of asphaltic residues on the seafloor represent ~40% of the original oil volume and mass, the estimated gas generated is 5.0×1010 kg (~76×109 m3) CH4 and/or 1.4×1011 kg CO2 over the lifetime of seepage needed to produce the volume of these deposits. Geologic relationships and oil weathering inferences suggest the deposits are of early Holocene age or even younger. Assuming an age of ~1,000 years, annual fluxes are on the order of 5.0×107 kg (~76×106 m3) and/or 1.4×108 kg for CH4 and CO2, respectively. The daily volumetric emission rate (2.1×105 m3) is comparable to current CH4 emission from Coal Oil Point seeps (1.5×105 m3/day), and may be a significant source of both CH4 and CO2 to the atmosphere provided that the gas can be transported through the water column.

  19. Carbon dioxide gas in hydrocarbon pools as a geochemical indicator of tapering traps (as in West Siberian fields)

    Energy Technology Data Exchange (ETDEWEB)

    Sidorenkov, A.T.

    1983-01-01

    Principal sources of carbon dioxide gas in oil pools of Western Siberia are carbonates, present in the makeup of the layer-collector horizons. All the hydrocarbon pools complicated by lithologic screens are characterized by increased concentrations of carbon dioxide in the gases dissolved in the oils. With a carbon dioxide content of more than 1 vol%, the probability of identifying the screen in the pools of Western Siberia is close to 100%.

  20. Carbon dioxide gas in hydrocarbon pools as a geochemical indicator of tapering traps (as in West Siberian fields)

    Energy Technology Data Exchange (ETDEWEB)

    Sidorenkov, A.T.

    1980-07-01

    Principal sources of carbon dioxide gas in oil pools of Western Siberia are carbonates, present in the makeup of the layer-collector horizons. All the hydrocarbon pools complicated by lithologic screens are characterized by increased concentrations of carbon dioxide in the gases dissolved in the oils. With a carbon dioxide content of more than 1 vol %, the probability of identifying the screen in the pools of Western Sibeia is close to 100%.

  1. Universal Indicators for Oil and Gas Prospecting Based on Bacterial Communities Shaped by Light-Hydrocarbon Microseepage in China.

    Science.gov (United States)

    Deng, Chunping; Yu, Xuejian; Yang, Jinshui; Li, Baozhen; Sun, Weilin; Yuan, Hongli

    2016-07-28

    Light hydrocarbons accumulated in subsurface soil by long-term microseepage could favor the anomalous growth of indigenous hydrocarbon-oxidizing microorganisms, which could be crucial indicators of underlying petroleum reservoirs. Here, Illumina MiSeq sequencing of the 16S rRNA gene was conducted to determine the bacterial community structures in soil samples collected from three typical oil and gas fields at different locations in China. Incubation with n-butane at the laboratory scale was performed to confirm the presence of "universal microbes" in light-hydrocarbon microseepage ecosystems. The results indicated significantly higher bacterial diversity in next-to-well samples compared with background samples at two of the three sites, which were notably different to oil-contaminated environments. Variation partitioning analysis showed that the bacterial community structures above the oil and gas fields at the scale of the present study were shaped mainly by environmental parameters, and geographic location was able to explain only 7.05% of the variation independently. The linear discriminant analysis effect size method revealed that the oil and gas fields significantly favored the growth of Mycobacterium, Flavobacterium, and Pseudomonas, as well as other related bacteria. The relative abundance of Mycobacterium and Pseudomonas increased notably after n-butane cultivation, which highlighted their potential as biomarkers of underlying oil deposits. This work contributes to a broader perspective on the bacterial community structures shaped by long-term light-hydrocarbon microseepage and proposes relatively universal indicators, providing an additional resource for the improvement of microbial prospecting of oil and gas.

  2. Gas chromatography mass spectrometry computer analysis of volatile halogenated hydrocarbons in man and his environment--A multimedia environmental study.

    Science.gov (United States)

    Barkley, J; Bunch, J; Bursey, J T; Castillo, N; Cooper, S D; Davis, J M; Erickson, M D; Harris, B S; Kirkpatrick, M; Michael, L C; Parks, S P; Pellizzari, E D; Ray, M; Smith, D; Tomer, K B; Wagner, R; Zweidinger, R A

    1980-04-01

    As part of a study to make a comparative analysis of selected halogenated compounds in man and the environmental media, a quantitative gas chromatography mass spectrometric analysis of the levels of the halogenated compounds found in the breath, blood and urine of an exposed population (Old Love Canal area, Niagara, New York) and their immediate environment (air and water) was undertaken. In addition, levels of halogenated hydrocarbons in air samples taken in the general Buffalo, Niagara Falls area were determined.

  3. Geology and hydrocarbon accumulations in the deepwater of the northwestern South China Sea-with focus on natural gas

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; SUN Zhipeng; ZHANG Daojun; ZHU Jitian; LI Xushen; HUANG Baojia; GUO Minggang; JIANG Rufeng

    2015-01-01

    The deepwater of the northwestern South China Sea is located in the central to southern parts of the Qiongdongnan Basin (QDN Basin), which is a key site for hydrocarbon exploration in recent years. In this study, the authors did a comprehensive analysis of gravity-magnetic data, extensive 3D seismic survey, cores and cuttings, paleontology and geochemical indexes, proposed the mechanism of natural gas origin, identified different oil and gas systems, and established the model of hydrocarbon accumulations in the deep-water region. Our basin tectonic simulation indicates that the evolution of QDN Basin was controlled by multiple-phased tectonic movements, such as Indochina-Eurasian Plate collision, Tibetan Uplift, Red River faulting and the expansion of the South China Sea which is characterized by Paleogene rifting, Neogene depression, and Eocene intensive faulting and lacustrine deposits. The drilling results show that this region is dominated by marine-terrestrial transitional and neritic-bathyal facies from the early Oligocene. The Yacheng Formation of the early Oligocene is rich in organic matter and a main gas-source rock. According to the geological-geochemical data from the latest drilling wells, Lingshui, Baodao, Changchang Sags have good hydrocarbon-generating potentials, where two plays from the Paleogene and Neogene reservoirs were developed. Those reservoirs occur in central canyon structural-lithologic trap zone, Changchang marginal trap zone and southern fault terrace of Baodao Sag. Among them, the central canyon trap zone has a great potential for exploration because the various reservoir-forming elements are well developed, i.e., good coal-measure source rocks, sufficient reservoirs from the Neogene turbidity sandstone and submarine fan, faults connecting source rock and reservoirs, effective vertical migration, late stage aggregation and favorable structural–lithological composite trapping. These study results provide an important scientific basis

  4. Processes in petroleum chemistry. Technical and economical characteristics Vol. 1. Synthesis gas and derivatives. Main hydrocarbon intermediaries (2 ed. )

    Energy Technology Data Exchange (ETDEWEB)

    Chauvel, A.; Lefebvre, G.; Castex, L.

    1985-01-01

    The aim of this book is to give rudiments for a preliminary study to outline petrochemical operation and cost estimation. Basic operations are examined: Steam reforming or partial oxidation, steam or thermal cracking and catalytic reforming. The main topics examined include: hydrogen purification, hydrogen fabrication from hydrocarbons, carbonaceous materials or water, production of carbon monoxide, ammoniac synthesis methanol synthesis from synthesis gas, preparation of formol, urea, acetylene and monomers for the preparation of plastics.

  5. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-04-05

    The purpose of this Model Report (REV02) is to document the unsaturated zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrological-chemical (THC) processes on UZ flow and transport. This Model Report has been developed in accordance with the ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this Model Report in Section 1.12, Work Package AUZM08, ''Coupled Effects on Flow and Seepage''. The plan for validation of the models documented in this Model Report is given in Attachment I, Model Validation Plans, Section I-3-4, of the TWP. Except for variations in acceptance criteria (Section 4.2), there were no deviations from this TWP. This report was developed in accordance with AP-SIII.10Q, ''Models''. This Model Report documents the THC Seepage Model and the Drift Scale Test (DST) THC Model. The THC Seepage Model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC model is a drift-scale process model relying on the same conceptual model and much of the same input data (i.e., physical, hydrological, thermodynamic, and kinetic) as the THC Seepage Model. The DST THC Model is the primary method for validating the THC Seepage Model. The DST THC Model compares predicted water and gas compositions, as well as mineral alteration patterns, with observed data from the DST. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal-loading conditions, and predict the evolution of mineral alteration and fluid chemistry around potential waste emplacement drifts. The

  6. Study on the law of methane seepage in the wall of drainage roadway in mining seam-group

    Institute of Scientific and Technical Information of China (English)

    LIU Jian; LUO Yong; LIU Ze-gong; SHI Bi-ming

    2005-01-01

    Based on the equation of the gas flow continuity and state, Darcy law and Langmuir equation, the law of methane seepage in the wall of drainage roadway was studied. The governing equation of methane one-way seepage in the seam was founded.By solving the equation, the calculation of methane seepage velocity in the coal wall was worked out. The result has really applied worth and will give beneficial references to related research, it provides preventing coal and gas outbursts with theoretical gist.

  7. Greenhouse gas impacts of declining hydrocarbon resource quality: Depletion, dynamics, and process emissions

    Science.gov (United States)

    Brandt, Adam Robert

    This dissertation explores the environmental and economic impacts of the transition to hydrocarbon substitutes for conventional petroleum (SCPs). First, mathematical models of oil depletion are reviewed, including the Hubbert model, curve-fitting methods, simulation models, and economic models. The benefits and drawbacks of each method are outlined. I discuss the predictive value of the models and our ability to determine if one model type works best. I argue that forecasting oil depletion without also including substitution with SCPs results in unrealistic projections of future energy supply. I next use information theoretic techniques to test the Hubbert model of oil depletion against five other asymmetric and symmetric curve-fitting models using data from 139 oil producing regions. I also test the assumptions that production curves are symmetric and that production is more bell-shaped in larger regions. Results show that if symmetry is enforced, Gaussian production curves perform best, while if asymmetry is allowed, asymmetric exponential models prove most useful. I also find strong evidence for asymmetry: production declines are consistently less steep than inclines. In order to understand the impacts of oil depletion on GHG emissions, I developed the Regional Optimization Model for Emissions from Oil Substitutes (ROMEO). ROMEO is an economic optimization model of investment and production of fuels. Results indicate that incremental emissions (with demand held constant) from SCPs could be 5-20 GtC over the next 50 years. These results are sensitive to the endowment of conventional oil and not sensitive to a carbon tax. If demand can vary, total emissions could decline under a transition because the higher cost of SCPs lessens overall fuel consumption. Lastly, I study the energetic and environmental characteristics of the in situ conversion process, which utilizes electricity to generate liquid hydrocarbons from oil shale. I model the energy inputs and outputs

  8. Surface geochemical data evaluation and integration with geophysical observations for hydrocarbon prospecting, Tapti graben, Deccan Syneclise, India

    Directory of Open Access Journals (Sweden)

    T. Satish Kumar

    2014-05-01

    Full Text Available The Deccan Syneclise is considered to have significant hydrocarbon potential. However, significant hydrocarbon discoveries, particularly for Mesozoic sequences, have not been established through conventional exploration due to the thick basalt cover over Mesozoic sedimentary rocks. In this study, near-surface geochemical data are used to understand the petroleum system and also investigate type of source for hydrocarbons generation of the study area. Soil samples were collected from favorable areas identified by integrated geophysical studies. The compositional and isotopic signatures of adsorbed gaseous hydrocarbons (methane through butane were used as surface indicators of petroleum micro-seepages. An analysis of 75 near-surface soil-gas samples was carried out for light hydrocarbons (C1–C4 and their carbon isotopes from the western part of Tapti graben, Deccan Syneclise, India. The geochemical results reveal sites or clusters of sites containing anomalously high concentrations of light hydrocarbon gases. High concentrations of adsorbed thermogenic methane (C1 = 518 ppb and ethane plus higher hydrocarbons (ΣC2+ = 977 ppb were observed. Statistical analysis shows that samples from 13% of the samples contain anomalously high concentrations of light hydrocarbons in the soil-gas constituents. This seepage suggests largest magnitude of soil gas anomalies might be generated/source from Mesozoic sedimentary rocks, beneath Deccan Traps. The carbon isotopic composition of methane, ethane and propane ranges are from −22.5‰ to −30.2‰ PDB, −18.0‰ to 27.1‰ PDB and 16.9‰–32.1‰ PDB respectively, which are in thermogenic source. Surface soil sample represents the intersection of a migration conduit from the deep subsurface to the surface connected to sub-trappean Mesozoic sedimentary rocks. Prominent hydrocarbon concentrations were associated with dykes, lineaments and presented on thinner basaltic cover in the study area

  9. Seasonal variation, sources and gas/particle partitioning of polycyclic aromatic hydrocarbons in Guangzhou, China.

    Science.gov (United States)

    Yang, Yunyun; Guo, Pengran; Zhang, Qian; Li, Deliang; Zhao, Lan; Mu, Dehai

    2010-05-15

    Air samples were collected weekly at an urban site and a suburban site in Guangzhou City, China, from April 2005 to March 2006, to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the ambient air and study their seasonal variations, gas/particle partitioning, origins and sources. The concentrations of summation Sigma16-PAHs (particle+gas) were 129.9+/-73.1 ng m(-)(3) at the urban site and 120.4+/-48.5 ng m(-)(3) at the suburban site, respectively. It was found that there was no significant difference in PAH concentrations between the urban and suburban sites. Seasonal variations of PAH concentrations at the two sampling sites were similar, with higher levels in the winter that gradually decreased to the lowest levels in the summer. The average concentrations of summation Sigma16-PAHs in the winter samples were approximately three times higher than those of the summer samples because in the summer local emissions dominated, and in the winter the contribution from outside sources or transported PAHs is increased. The plot of logK(p) versus logP(L)(0) for the data sets of summer and winter season samples had significantly different slopes at both sampling sites. The slopes for the winter samples were steeper than those for the summer samples. It was also observed that gas/particle partitioning of PAHs showed different characteristics depending on air parcel trajectories. Steeper slopes were obtained for an air parcel that traveled across the continent to the sampling site from the northern or northeastern sector, whereas shallower slopes were obtained for air masses that traveled across the sea from the southern or eastern sector. Diagnostic ratio analytical results imply that the origins of PAHs were mainly from petroleum combustion and coal/biomass burning. The anthracene/phenanthrene and benzo[a]anthracene/chrysene ratios in the winter were significantly lower than those in the summer, which indicate that there might be long

  10. The hydrocarbon sphere

    Energy Technology Data Exchange (ETDEWEB)

    Mandev, P.

    1984-01-01

    The hydrocarbon sphere is understood to be the area in which hydrocarbon compounds are available. It is believed that the lower boundary on the hydrocarbon sphere is most probably located at a depth where the predominant temperatures aid in the destruction of hydrocarbons (300 to 400 degrees centigrade). The upper limit on the hydrocarbon sphere obviously occurs at the earth's surface, where hydrocarbons oxidize to H20 and CO2. Within these ranges, the occurrence of the hydrocarbon sphere may vary from the first few hundred meters to 15 kilometers or more. The hydrocarbon sphere is divided into the external (mantle) sphere in which the primary gas, oil and solid hydrocarbon fields are located, and the internal (metamorphic) sphere containing primarily noncommercial accumulations of hydrocarbon gases and solid carbon containing compounds (anthraxilite, shungite, graphite, etc.) based on the nature and scale of hydrocarbon compound concentrations (natural gas, oil, maltha, asphalt, asphaltite, etc.).

  11. Quantification of Seepage in Groundwater Dependent Wetlands

    DEFF Research Database (Denmark)

    Johansen, Ole; Beven, Keith; Jensen, Jacob Birk

    2017-01-01

    Restoration and management of groundwater dependent wetlands require tools for quantifying the groundwater seepage process. A method for determining point estimates of the groundwater seepage based on water level observations is tested. The study is based on field data from a Danish rich fen....... Therefore secondly a much simpler mass balance approach is used with lumped descriptions of the most important hydrological processes controlling water level and groundwater inflow to the system. The water level dynamics are here described and bracketed nicely and a dynamic description of the seepage rate...... the dynamic description of groundwater seepage can be very useful in future studies of the links between seepage, soil water chemistry and vegetation in groundwater dependent terrestrial ecosystems....

  12. An experimental study of different hydrocarbon components in natural gas and their impact on engine performance in a HCCI engine

    Energy Technology Data Exchange (ETDEWEB)

    Aaberg, Kristoffer

    2000-07-01

    Natural gas is a well suited fuel for HCCI (Homogenous Charge Compression Ignition) operation. Commercial natural gas consists of many different hydrocarbons where the lighter hydrocarbons, methane, ethane propane and butane are the most common and methane having the highest percentage. The composition of natural gas varies widely all over the world. It is well known that the higher hydrocarbons have a great impact on the ignition characteristics. As a spontaneous auto-ignition process initiates HCCI, this type of engine is very sensitive of the fuels ignition characteristics. To investigate the influence of the higher hydrocarbons an extensive test series was carried out. The impact of different concentrations of ethane, propane, iso- and n-butane were tested. Using different equivalence ratios, concentrations of the hydrocarbons, levels of EGR and levels of boost pressure the tests were carried out. Data collected during the testing were emission, mass flow, indicated mean effective pressure, inlet temperature and engine speed. From these data, specific emissions and efficiencies could be calculated. As a test a value of released heat per cycle was also evaluated, and used to check the mass flow. The results show that the ignition characteristics of the charge is very sensitive to fuel composition. A strong connection between the required inlet air temperature and the fuel composition was detected. With an increasing amount of heavier components in the gas, this temperature was decreased. This is connected to the octane number of the components. Much of the engine performance can be related to this change of temperature. Emissions and power output (imep) showed the highest dependency of the concentration of component gas. Butanes had the highest impact on the inlet temperature, followed by propane and ethane. With the use of 20% EGR the inlet temperature had to be raised. The impact of the component gases was the same as with no EGR. The combustion efficiency

  13. Global distribution and Gas-particle Partitioning of Polycyclic Aromatic Hydrocarbons - a Modelling Study

    Science.gov (United States)

    Lammel, G.; Sehili, A. M.

    2009-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are emitted in all combustion processes. Some undergo re-volatilisation (multi-hopping). Little is known about degradation pathways and the processes determining gas-particle partitioning (Lohmann & Lammel, 2004). Distribution and fate have no been studied on the global scale so far (except for emissions in Europe and Russia; Sehili & Lammel, 2007). Anthracene (ANT), fluoranthene (FLT) and benzo[a]pyrene (BAP) have been studied under present-day climate and each 3 scenarios of atmospheric degradation and gas-particle partitioning using an atmospheric general circulation model with embedded dynamic aerosol submodel, ECHAM-HAM (Stier et al., 2005) and re-volatilization from ground compartments (Semeena et al., 2006). 10 years were simulated with a time-step of 30 min and 2.8°x2.8° and 19 levels. Emissions were compiled based on emission factors in 27 major types of combustion technologies, scaled to 141 combustion technologies and their global distribution as of 1996 (1°x1°) according to fuel type and the PM1 emission factor (Bond et al., 2004). The emissions were entried uniformly throughout the entire simulation time. Scenarios tested: AD = adsorption (according to the Junge empirical relationship; Pankow, 1987), OB = absorption in organic matter and adsorption to soot (Lohmann & Lammel, 2004) without and DP = with degradation in the atmospheric particulate phase. Gas-particle partitioning in air influences drastically the atmospheric cycling, total environmental fate (e.g. compartmental distributions) and the long-range transport potential (LRTP) of the substances studied. The LRTP is mostly regional. Comparison with observed levels indicate that degradation in the particulate phase must be slower than in the gas-phase. Furthermore, the levels of semivolatile PAHs (ANT and FLT) at high latitudes and a European mid latitude site cannot be explained by partitioning due to adsorption alone, but point to both absorption into

  14. Hydrogen Selective Inorganic membranes for Gas Separations under High Pressure Intermediate Temperature Hydrocarbonic Envrionment

    Energy Technology Data Exchange (ETDEWEB)

    Rich Ciora; Paul KT Liu

    2012-06-27

    In this project, we have successfully developed a full scale commercially ready carbon molecular sieve (CMS) based membrane for applications in H{sub 2} recovery from refinery waste and other aggressive gas streams. Field tests at a refinery pilot plant and a coal gasification facility have successfully demonstrated its ability to recovery hydrogen from hydrotreating and raw syngas respectively. High purity H{sub 2} and excellent stability of the membrane permeance and selectivity were obtained in testing conducted over >500 hours at each site. The results from these field tests as well as laboratory testing conclude that the membranes can be operated at high pressures (up to 1,000 psig) and temperatures (up to 300 C) in presence of aggressive contaminants, such as sulfur and nitrogen containing species (H{sub 2}S, CO{sub 2}, NH{sub 3}, etc), condensable hydrocarbons, tar-like species, heavy metals, etc. with no observable effect on membrane performance. By comparison, similar operating conditions and/or environments would rapidly destroy competing membranes, such as polymeric, palladium, zeolitic, etc. Significant cost savings can be achieved through recovering H{sub 2} from refinery waste gas using this newly developed CMS membrane. Annual savings of $2 to 4MM/year (per 20,000 scfd of waste gas) can be realized by recovering the H{sub 2} for reuse (versus fuel). Projecting these values over the entire US market, potential H{sub 2} savings from refinery waste gases on the order of 750 to 1,000MM scfd and $750 to $1,000MM per year are possible. In addition to the cost savings, potential energy savings are projected to be ca. 150 to 220 tBTU/yr and CO{sub 2} gas emission reductions are projected to be ca. 5,000 to 6,500MMtons/year. The full scale membrane bundle developed as part of this project, i.e., 85 x 30 inch ceramic membrane tubes packaged into a full ceramic potting, is an important accomplishment. No comparable commercial scale product exists in the

  15. Determination of polycyclic aromatic hydrocarbons [PAHs] in processed meat products using gas chromatography - flame ionization detector.

    Science.gov (United States)

    Olatunji, Olatunde S; Fatoki, Olalekan S; Opeolu, Beatrice O; Ximba, Bhekumusa J

    2014-08-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in smoked, grilled and boiled meats were determined using gas chromatography - flame ionization detector (GC-FID). PAHs in the processed meats were extracted in n-hexane after hydrolysis with methanolic KOH. Clean-up was achieved using solid phase extraction in neutral-Si/basic-Si/acidic-Si/neutral-Si frits. The fractions, benzo[k]fluoranthene (BkP), benzo[a]pyrene (BaP), indeno[123-cd]pyrene (IP) and benzo[ghi]perylene (BghiP) were separated and quantified using GC-FID. The method and instrument limits of detections were 0.1, 0.1, 0.2, 0.3μg/kg and 0.5, 0.5, 1.0, 1.5μg/kg, respectively, for BkP, BaP, IP and BghiP. The method's recovery and precision generally varied between 83.69% and 94.25% with relative standard deviation (RSD) of 3.18-15.60%; and 90.38-96.71% with relative standard deviation (RSD) of 1.82-12.87% respectively. The concentration of BkP, BaP, IP and BghiP in smoked, grilled and boiled meat samples were ranged 0.64-31.54μg/kg, 0.07-7.04μg/kg, 0.09-15.03, 0.51-46.67μg/kg and 0.01-5.11μg/kg, respectively.

  16. Analysis of 23 polycyclic aromatic hydrocarbons in smokeless tobacco by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Stepanov, Irina; Villalta, Peter W; Knezevich, Aleksandar; Jensen, Joni; Hatsukami, Dorothy; Hecht, Stephen S

    2010-01-01

    Smokeless tobacco contains 28 known carcinogens and causes precancerous oral lesions and oral and pancreatic cancer. A recent study conducted by our research team identified eight different polycyclic aromatic hydrocarbons (PAHs) in U.S. moist snuff, encouraging further investigations of this group of toxicants and carcinogens in smokeless tobacco products. In this study, we developed a gas chromatography-mass spectrometry method that allows simultaneous analysis of 23 various PAHs in smokeless tobacco after a simple two-step extraction and purification procedure. The method produced coefficients of variation under 10% for most PAHs. The limits of quantitation for different PAHs varied between 0.3 and 11 ng/g tobacco, starting with a 300 mg sample. The recovery of the stable isotope-labeled internal standards averaged 87%. The method was applied to analysis of 23 moist snuff samples that included various flavors of the most popular U.S. moist snuff brands, as well as 17 samples representing the currently marketed brands of spit-free tobacco pouches, a relatively new type of smokeless tobacco. The sum of all detected PAHs in conventional moist snuff averaged 11.6 (+/-3.7) microg/g dry weight; 20% of this amount was comprised of carcinogenic PAHs. The levels of PAHs in new spit-free tobacco products were much lower than those in moist snuff; the sum of all detected PAHs averaged 1.3 (+/-0.28) microg/g dry weight. Our findings render PAHs one of the most prevalent groups of carcinogens in smokeless tobacco. Urgent measures are required from the U.S. tobacco industry to modify manufacturing processes so that the levels of these toxicants and carcinogens in U.S. moist snuff are greatly reduced.

  17. Seepage Model for PA Including Dift Collapse

    Energy Technology Data Exchange (ETDEWEB)

    G. Li; C. Tsang

    2000-12-20

    The purpose of this Analysis/Model Report (AMR) is to document the predictions and analysis performed using the Seepage Model for Performance Assessment (PA) and the Disturbed Drift Seepage Submodel for both the Topopah Spring middle nonlithophysal and lower lithophysal lithostratigraphic units at Yucca Mountain. These results will be used by PA to develop the probability distribution of water seepage into waste-emplacement drifts at Yucca Mountain, Nevada, as part of the evaluation of the long term performance of the potential repository. This AMR is in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (CRWMS M&O 2000 [153447]). This purpose is accomplished by performing numerical simulations with stochastic representations of hydrological properties, using the Seepage Model for PA, and evaluating the effects of an alternative drift geometry representing a partially collapsed drift using the Disturbed Drift Seepage Submodel. Seepage of water into waste-emplacement drifts is considered one of the principal factors having the greatest impact of long-term safety of the repository system (CRWMS M&O 2000 [153225], Table 4-1). This AMR supports the analysis and simulation that are used by PA to develop the probability distribution of water seepage into drift, and is therefore a model of primary (Level 1) importance (AP-3.15Q, ''Managing Technical Product Inputs''). The intended purpose of the Seepage Model for PA is to support: (1) PA; (2) Abstraction of Drift-Scale Seepage; and (3) Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR). Seepage into drifts is evaluated by applying numerical models with stochastic representations of hydrological properties and performing flow simulations with multiple realizations of the permeability field around the drift. The Seepage Model for PA uses the distribution of permeabilities derived from air injection testing in

  18. Dynamics of the gas-liquid interfacial reaction of O(1D) with a liquid hydrocarbon.

    Science.gov (United States)

    Waring, Carla; King, Kerry L; Costen, Matthew L; McKendrick, Kenneth G

    2011-06-30

    The dynamics of the gas-liquid interfacial reaction of the first electronically excited state of the oxygen atom, O((1)D), with the surface of a liquid hydrocarbon, squalane (C(30)H(62); 2,6,10,15,19,23-hexamethyltetracosane) has been studied experimentally. Translationally hot O((1)D) atoms were generated by 193 nm photolysis of a low pressure (nominally 1 mTorr) of N(2)O a short distance (mean = 6 mm) above a continually refreshed liquid squalane surface. Nascent OH (X(2)Π, v' = 0) reaction products were detected by laser-induced fluorescence (LIF) on the OH A(2)Σ(+)-X(2)Π (1,0) band at the same distance above the surface. The speed distribution of the recoiling OH was characterized by measuring the appearance profiles as a function of photolysis-probe delay for selected rotational levels, N'. The rotational (and, partially, fine-structure) state distributions were also measured by recording LIF excitation spectra at selected photolysis-probe delays. The OH v' = 0 rotational distribution is bimodal and can be empirically decomposed into near thermal (~300 K) and much hotter (~6000 K) Boltzmann-temperature components. There is a strong positive correlation between rotational excitation and translation energy. However, the colder rotational component still represents a significant fraction (~30%) of the fastest products, which have substantially superthermal speeds. We estimate an approximate upper limit of 3% for the quantum yield of OH per O((1)D) atom that collides with the surface. By comparison with established mechanisms for the corresponding reactions in the gas phase, we conclude that the rotationally and translationally hot products are formed via a nonstatistical insertion mechanism. The rotationally cold but translationally hot component is most likely produced by direct abstraction. Secondary collisions at the liquid surface of products of either of the previous two mechanisms are most likely responsible for the rotationally and translationally cold

  19. The influence of aerosol size and organic carbon content on gas/particle partitioning of polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Offenberg, J.H.; Baker, J.E. [University of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.

    2002-07-01

    Concentrations of polycyclic aromatic hydrocarbons (Paths) were measured on size segregated airborne particulate matter and in the gas phase during 12h periods in urban Chicago and over southern Lake Michigan during July 1994 and January 1995 as part of the atmospheric exchange over lakes and oceans (AEOLOS) project. In the 19 paired gas phase and size segregated particle samples, partition coefficients of polycyclic aromatic hydrocarbons are well correlated with the sub-cooled liquid vapor pressure, (p{sub l}{sup 0}) within an aerosol size class. However, partition coefficients differ systematically according to particle size and aerosol organic carbon content. Approximately 68% of the observed variability in measured PAH partition coefficients is explained by a three dimensional multiple linear regression that includes vapor pressure of the compound of interest, aerosol particle aerodynamic equivalent diameter, aerosol organic carbon content and interaction terms. However, addition of both particle size and the fraction organic carbon terms, while statistically significant, appear to be of minimal importance in improving our ability to model gas/particle partitioning in the atmosphere. The influence of either particle size or fraction organic carbon is nearly as large as the calculated random error in partition coefficients, and suggests that an important factor in predicting gas/particle partitioning has not yet been incorporated in the current model. [author].

  20. Spatial distribution of methane seepage on the East Siberian Arctic Shelf

    Science.gov (United States)

    Stubbs, C.; Leifer, I.; Shakhova, N. E.; Semiletov, I. P.; Luyendyk, B. P.

    2010-12-01

    A 2009 multibeam sonar survey of the shallow water-column (mean depth 10 m), near-coastal region of the East Siberian Arctic Shelf (ESAS) adjacent to the Lena River Delta detected tens of thousands of widespread bubble plume seeps. The ESAS contains an estimated 1400 GT (109 tons = 1 GT) of carbon sequestered within and beneath a sub-sea permafrost unit that has become inundated due to sea-level transgression over the last ~15,000 years. This carbon pool includes methane (CH4) as free and dissolved gas, as well as potentially extensive methane hydrate deposits, yet its contribution to global carbon stocks has traditionally been ignored due to the assumed integrity of the sub-sea permafrost as an impermeable barrier to hydrocarbon migration. Recent results indicate that in some regions of the ESAS, methane is migrating through destabilized permafrost into the shallow water-column from which it efficiently vents to the atmosphere. This process represents an unknown but potentially significant contribution to the global greenhouse gas budget and is likely to accelerate under global warming scenarios. We hypothesize that the mapped seeps are fed by methane deposits within and beneath capping permafrost units that release gas into the thin overlying sediments through columns of thaw sediments and other permeable structures within the permafrost. Such sub-sea permafrost features have been previously identified in association with isolated bubble plumes in the ESAS as close as 25 km from the study area (Rekant et al., 2009). These proposed migration pathways suggest thermal destabilization within the subsea permafrost cap; however, the rates at which these processes are occurring remain unknown. The spatial distributions of the most numerous and intense areas of seepage correlate with the areas of greatest fluvial discharge from the Lena and Olenek Rivers and their tributaries. This thermal influence is also evident in seasonal time series of adjacent sea ice retreat over

  1. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers.

    Science.gov (United States)

    Liu, Zhen-Shu; Li, Wen-Kai; Hung, Ming-Jui

    2014-09-01

    Incineration flue gas contains polycyclic aromatic hydrocarbons (PAHs) and sulfur dioxide (SO2). The effects of SO2 concentration (0, 350, 750, and 1000 ppm), reaction temperature (160, 200, and 280 degrees C), and the type of activated carbon fibers (ACFs) on the removal of SO2 and PAHs by ACFs were examined in this study. A fluidized bed incinerator was used to simulate practical incineration flue gas. It was found that the presence of SO2 in the incineration flue gas could drastically decrease removal of PAHs because of competitive adsorption. The effect of rise in the reaction temperature from 160 to 280 degrees C on removal of PAHs was greater than that on SO2 removal at an SO2 concentration of 750 ppm. Among the three ACFs studied, ACF-B, with the highest microporous volume, highest O content, and the tightest structure, was the best adsorbent for removing SO2 and PAHs when these gases coexisted in the incineration flue gas. Implications: Simultaneous adsorption of sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs) emitted from incineration flue gas onto activated carbon fibers (ACFs) meant to devise a new technique showed that the presence of SO2 in the incineration flue gas leads to a drastic decrease in removal of PAHs because of competitive adsorption. Reaction temperature had a greater influence on PAHs removal than on SO2 removal. ACF-B, with the highest microporous volume, highest O content, and tightest structure among the three studied ACFs, was found to be the best adsorbent for removing SO2 and PAHs.

  2. Process for separating C/sub 2+/ hydrocarbons from natural gas. Verfahren zur Abtrennung von C/sub 2+/-Kohlenwasserstoffen aus Erdgas

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, H.; Sapper, R.

    1987-03-05

    A process for separating C/sub 2+/ hydrocarbons from natural gas is claimed in which the natural gas is cooled, partially condensed, and separated into a liquid and a gaseous fraction. The liquid fraction is subcooled, expanded in the top region of a rectification column, and mixed with the expanded gaseous fraction. The rectification process produces a product flow containing C/sub 2+/ hydrocarbons, and a residual gas containing mostly lower-boiling constituents. The residual gas is heated up by indirect heat exchange with condensate and then by heat exchange with the gaseous fraction after partial condensation and with the natural gas led into the partial condensation process. The heated residual gas is expanded, producing work, and heated again by heat exchange with the natural gas to be cooled.

  3. Geologic characteristics, controlling factors and hydrocarbon accumulation mechanisms of China’s Large Gas Provinces of low porosity and permeability

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the analysis of the geological characteristics and controlling factors, we analyzed the formation mechanism of different types of gas reservoirs. The main characteristics of gas provinces with low porosity and permeability are mainly as follows: large area, low abundance, small gas pools and large gas provinces; widely distributed excellent hydrocarbon source rocks with closely contacted source-reservoir-cap association; development mainly in large continental depressions or in paralic shallow-river delta systems; many kinds of traps coexisting in large areas, dominantly para-layered lithologic, digenetic and capillary pressure traps; double fluid flow mechanisms of Darcy flow and non-Darcy flow; complicated gas and water relations; and having the resource distribution of highly productive "sweet spots", banding concentration, and macroscopically large areas integrated. The main controlling factors of large sandstone gas provinces with low porosity and permeability are stable dynamic backgrounds and gentle structural frameworks which control the extensive distribution of alternate (interbedded) sandstones and mudstones; weak hydropower of large gentle lake basins controlling the formation of discontinuous, low porosity and permeability reservoirs in shallow-water deltas; regionally differential diagenesis and no homogeneous digenetic facies controlling the development of favorable reservoirs and digenetic traps; and weak and dispersive reservoir-forming dynamic forces leading to the widely distributed small traps with low abundance. Low porosity and permeability gas provinces with different trap types have different formation mechanisms which include fluid diversion pressure difference interactive mechanism of lithologic-trap gas accumulations, separated differential collection mechanism of digenetic-trap gas accumulations, and the Non-Darcy flow mechanism of capillary-pressure gas accumulations.

  4. Geolosic characteristics, controlling factors and hydrocarbon accumulation mechanisms of China's Large Gas Provinces of low porosity and permeability

    Institute of Scientific and Technical Information of China (English)

    ZOU CaiNeng; TAO ShiZhen; ZHANG XiangXiang; HE DongBo; ZHOU ChuanMin; GAO XiaoHui

    2009-01-01

    Based on the analysis of the geological characteristics and controlling factors, we analyzed the formation mechanism of different types of gas reservoirs. The main characteristics of gas provinces with low porosity and permeability are mainly as follows: large area, low abundance, small gas pools and large gas provinces; widely distributed excellent hydrocarbon source rocks with closely contacted source-reservoir-cap association; development mainly in large continental depressions or in paralic shallow-river delta systems; many kinds of traps coexisting in large areas, dominantly para-layered lithologic, digenetic and capillary pressure traps; double fluid flow mechanisms of Darcy flow and non-Darcy flow; complicated gas and water relations; and having the resource distribution of highly productive "sweet spots", banding concentration, and macroscopically large areas integrated. The main controlling factors of large sandstone gas provinces with low porosity and permeability are stable dynamic backgrounds and gentle structural frameworks which control the extensive distribution of alternate (interbedded) sandstones and mudstones; weak hydropower of large gentle lake basins controlling the formation of discontinuous, low porosity and permeability reservoirs in shallow-water del-tas; regionally differential diagenesis and no homogeneous digenetic facies controlling the development of favorable reservoirs and digenetic traps; and weak and dispersive reservoir-forming dynamic forces leading to the widely distributed small traps with low abundance. Low porosity and permeability gas provinces with different trap types have different formation mechanisms which include fluid diversion pressure difference interactive mechanism of lithologic-trap gas accumulations, separated differential collection mechanism of digenetic-trap gas accumulations, and the Non-Darcy flow mechanism of capillary-pressure gas accumulations.

  5. Mass transfer phenomena of gaseous hydrocarbons and nitrogen dioxide across gas-inorganic pigments boundaries

    Science.gov (United States)

    Birbatakou, S.; Pagopoulou, I.; Kalantzopoulos, A.; Roubani-Kalantzopoulou, F.

    1998-11-01

    Reversed-flow gas chromatography was used to study the kinetics of the action of five hydrocarbons namely, ethane, ethene, ethyne, propene and butene and of the nitrogen dioxide, on three known and widely used pigments, the white one TiO2, and the yellows CdS and PbCrO4. The calculation of kinetic parameters and mass transfer coefficients is based on an experimental adsorption isotherm. All these calculations are based on a non linear adsorption isotherm model as it is well accepted that the linear one is inadequate for inorganic substances like these mentioned in this work. The inadequacy is mainly attributed to the non-uniformity of the solid surface. Five physicochemical parameters have been obtained for each of the twenty heterogeneous reactions studied. With these systematic experiments under conditions which are similar to the atmospheric ones, an extrapolation of the results obtained to “real" atmospheres with a high degree of confidence is possible. Some of the calculations were based on the linear model for comparison. La cinétique de la réaction de cinq hydrocarbures (éthane, éthylène, acétylène, propène, boutène) et du dioxyde d'azote avec trois pigments (le blanc de TiO2 et les jaunes de CdS et PbCrO4) a été étudiée par chromatographie en phase gazeuse a flux inversé. Le calcul des paramètres cinétiques et des coefficients de transfert de masse a été effectué à partir des isothermes d'adsorption expérimentales en faisant l'hypothèse d`un modèle d'adsorption non-linéaire, qui résulte de la non-uniformité de la surface. Cinq paramètres physico-chimiques ont été obténus pour chacune des vingt réaction hétérogènes étudiées. À partir de ces résultats obténus dans des conditions similaires aux conditions atmosphériques, l'extrapolation à des atmosphères réelles paraît possible avec une bonne confiance. Quelques calculs ont été effectués avec un modèle linéaire pour comparaison.

  6. Application of geo-microbial prospecting method for finding oil and gas reservoirs

    Science.gov (United States)

    Rasheed, M. A.; Hasan, Syed Zaheer; Rao, P. L. Srinivasa; Boruah, Annapurna; Sudarshan, V.; Kumar, B.; Harinarayana, T.

    2015-03-01

    Microbial prospecting of hydrocarbons is based on the detection of anomalous population of hydrocarbon oxidizing bacteria in the surface soils, indicates the presence of subsurface oil and gas accumulation. The technique is based on the seepage of light hydrocarbon gases such as C1-C4 from the oil and gas pools to the shallow surface that provide the suitable conditions for the development of highly specialized bacterial population. These bacteria utilize hydrocarbon gases as their only food source and are found enriched in the near surface soils above the hydrocarbon bearing structures. The methodology involves the collection of soil samples from the survey area, packing, preservation and storage of samples in pre-sterilized sample bags under aseptic and cold conditions till analysis and isolation and enumeration of hydrocarbon utilizing bacteria such as methane, ethane, propane, and butane oxidizers. The contour maps for the population density of hydrocarbon oxidizing bacteria are drawn and the data can be integrated with geological, geochemical, geophysical methods to evaluate the hydrocarbon prospect of an area and to prioritize the drilling locations thereby reducing the drilling risks and achieve higher success in petroleum exploration. Microbial Prospecting for Oil and Gas (MPOG) method success rate has been reported to be 90%. The paper presents details of microbial prospecting for oil and gas studies, excellent methodology, future development trends, scope, results of study area, case studies and advantages.

  7. Simultaneous measurement of the concentrations of soot particles and gas species in light hydrocarbon flames using mass spectrometry

    Science.gov (United States)

    Li, Qingxun; Liu, Fang; Wang, Dezheng; Wang, Tiefeng

    2014-10-01

    Besides gas species concentrations, soot volume fractions are also important data in the study of flames. This work describes the simultaneous measurement of the concentrations of soot and gas species in light hydrocarbon flames by in situ sampling and mass spectrometry (MS).The reaction medium was frozen by sampling into a very low-pressure tube, and the soot selectivity (proportion of carbon atoms in the reactant converted to soot) was determined from the C and H mass balances using the measured concentrations of the gas species and the mass of soot present per unit gas volume. The H/C ratio of the soot was measured by a thermogravimetry-mass spectrometry combination. The soot volume fraction was calculated from the soot selectivity and density of the soot. The soot selectivity measured by this reduced pressure sampling mass spectrometry (RPSMS) method was verified by measurements using the gravimetric sampling technique where the mass of soot collected in a volume of gas was weighed by a high precision balance. For most of the measurements, the uncertainty in the soot volume fraction was ±5%, but this would be larger when the soot volume fractions are less than 1 ppm. For demonstration, the RPSMS method was used to study a methane fuel-rich flame where the soot volume fractions were 1-5 ppm. The simultaneous measurement of concentrations of soot and gas species is useful for the quantitative study of flames.

  8. Quality assurance of commercial beeswax. Part I. Gas chromatography-electron impact ionization mass spectrometry of hydrocarbons and monoesters.

    Science.gov (United States)

    Jiménez, J J; Bernal, J L; Aumente, S; del Nozal, Ma J; Martín, Ma T; Bernal, J

    2004-01-23

    The use of low-temperature capillary gas chromatography coupled to electron impact mass spectrometry for the characterization of crude beeswaxes yielded by Apis mellifera is described. The system allows the identification of a great number of compounds, some of them not reported till now in beeswax, such as a family of ethyl esters, tetracosyl oleate, and several saturated and unsaturated hydrocarbons. The information acquired makes possible the differentiation between pure beeswax and some foundation beeswax samples where mixture of pure beeswax with another substances is suspected.

  9. Detailed analysis of petroleum hydrocarbon attenuation in biopiles by high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Mao, Debin; Lookman, Richard; Van De Weghe, Hendrik; Van Look, Dirk; Vanermen, Guido; De Brucker, Nicole; Diels, Ludo

    2009-02-27

    Enhanced bioremediation of petroleum hydrocarbons in two biopiles was quantified by high-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GCXGC). The attenuation of 34 defined hydrocarbon classes was calculated by HPLC-GCXGC analysis of representative biopile samples at start-up and after 18 weeks of biopile operation. In general, a-cyclic alkanes were most efficiently removed from the biopiles, followed by monoaromatic hydrocarbons. Cycloalkanes and polycyclic aromatic hydrocarbons (PAHs) were more resistant to degradation. A-cyclic biomarkers farnesane, trimethyl-C13, norpristane, pristane and phytane dropped to only about 10% of their initial concentrations. On the other hand, C29-C31 hopane concentrations remained almost unaltered after 18 weeks of biopile operation, confirming their resistance to biodegradation. They are thus reliable indicators to estimate attenuation potential of petroleum hydrocarbons in biopile processed soils.

  10. Effects of Atmospheric Dynamics on CO2 Seepage at Mammoth Mountain, California USA

    Directory of Open Access Journals (Sweden)

    Egemen Ogretim

    2013-12-01

    Full Text Available In the past few decades, atmospheric effects on the variation of seepage from soil have been studied in disciplines such as volcanology, environmental protection, safety and health hazard avoidance. Recently, monitoring of potential leakage from the geologic sequestration of carbon has been added to this list. Throughout these diverse fields, barometric pumping and presence of steady winds are the two most commonly investigated atmospheric factors. These two factors have the effect of pumping gas into and out of the unsaturated zone, and sweeping the gas in the porous medium. This study focuses on two new factors related to atmosphere in order to explain the CO2 seepage anomalies observed at the Horseshoe Lake tree kill near Mammoth Mountain, CA, where the temporal variation of seepage due to a storm event could not be explained by the two commonly studied effects. First, the interaction of the lower atmospheric dynamics and the ground topography is considered for its effect on the seepage variation over an area that is linked through high-porosity, high-permeability soils and/or fracture networks. Second, the regional pressure fronts that impose significant pressure oscillation over an area are studied. The comparison of the computer simulation results with the experimental measurements suggests that the seepage anomaly observed at the Horseshoe Lake Tree Kill could be due to the unsteady effects caused by regional pressure fronts.

  11. On leakage and seepage from geological carbon sequestration sites

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, C.M.; Unger, A.J.A.; Hepple, R.P.; Jordan, P.D.

    2002-07-18

    Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable formations referred to here as brine formations. Injected CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} is trapped in the subsurface by any of these mechanisms, it is effectively sequestered away from the atmosphere where it would otherwise act as a greenhouse gas. The purpose of this report is to summarize our work aimed at quantifying potential CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO{sub 2} over the range of conditions from the deep subsurface to the vadose zone (Section 2), and then discuss conceptual models for how leakage might occur (Section 3). The discussion includes consideration of gas reservoir and natural gas storage analogs, along with some simple estimates of seepage based on assumed leakage rates. The conceptual model discussion provides the background for the modeling approach wherein we focus on simulating transport in the vadose zone, the last potential barrier to CO{sub 2} seepage (Section 4). Because of the potentially wide range of possible properties of actual future geologic sequestration sites, we carry out sensitivity analyses by

  12. Flow rate logging seepage meter

    Science.gov (United States)

    Reay, William G. (Inventor); Walthall, Harry G. (Inventor)

    1996-01-01

    An apparatus for remotely measuring and logging the flow rate of groundwater seepage into surface water bodies. As groundwater seeps into a cavity created by a bottomless housing, it displaces water through an inlet and into a waterproof sealed upper compartment, at which point, the water is collected by a collection bag, which is contained in a bag chamber. A magnet on the collection bag approaches a proximity switch as the collection bag fills, and eventually enables the proximity switch to activate a control circuit. The control circuit then rotates a three-way valve from the collection path to a discharge path, enables a data logger to record the time, and enables a pump, which discharges the water from the collection bag, through the three-way valve and pump, and into the sea. As the collection bag empties, the magnet leaves the proximity of the proximity switch, and the control circuit turns off the pump, resets the valve to provide a collection path, and restarts the collection cycle.

  13. Thermal cracking of recycled hydrocarbon gas-mixtures for re-pyrolysis: Operational analysis of some industrial furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Gal, T. [MOL PETCHEM Division, Tisza Chemical Works Co. Ltd. (TVK), P.O. Box 20, H-3581 Tiszaujvaros (Hungary); Lakatos, B.G. [Department of Process Engineering, University of Pannonia, P.O. Box 158, H-8200 Veszprem (Hungary)

    2008-02-15

    Thermal decomposition process of recycled hydrocarbon gas-mixtures in industrial furnaces is analyzed by computer simulation. The detailed kinetic and mathematical model developed was validated by using the process control laboratory cracked gas analysis of an industrially operated furnace. The effects of feed compositions and operational conditions are examined to select the favorable operating parameters and to achieve the possibly highest online operation period of the furnace. The effect of deposited coke on the lifetime of radiant coils is examined by a heat-transfer model. The simulation study confirmed that temporal variations of the feedstock composition could be harmonized well with the operating parameters of furnaces with the purpose of achieving maximum effectiveness. (author)

  14. Estimating Emissions of Toxic Hydrocarbons from Natural Gas Production Sites in the Barnett Shale Region of Northern Texas.

    Science.gov (United States)

    Marrero, Josette E; Townsend-Small, Amy; Lyon, David R; Tsai, Tracy R; Meinardi, Simone; Blake, Donald R

    2016-10-04

    Oil and natural gas operations have continued to expand and move closer to densely populated areas, contributing to growing public concerns regarding exposure to hazardous air pollutants. During the Barnett Shale Coordinated Campaign in October, 2013, ground-based whole air samples collected downwind of oil and gas sites revealed enhancements in several potentially toxic volatile organic compounds (VOCs) when compared to background values. Molar emissions ratios relative to methane were determined for hexane, benzene, toluene, ethylbenzene, and xylene (BTEX compounds). Using methane leak rates measured from the Picarro mobile flux plane (MFP) system and a Barnett Shale regional methane emissions inventory, the rates of emission of these toxic gases were calculated. Benzene emissions ranged between 51 ± 4 and 60 ± 4 kg h(-1). Hexane, the most abundantly emitted pollutant, ranged from 642 ± 45 to 1070 ± 340 kg h(-1). While observed hydrocarbon enhancements fall below federal workplace standards, results may indicate a link between emissions from oil and natural gas operations and concerns about exposure to hazardous air pollutants. The larger public health risks associated with the production and distribution of natural gas are of particular importance and warrant further investigation, particularly as the use of natural gas increases in the United States and internationally.

  15. Gas- and particle-phase distribution of polycyclic aromatic hydrocarbons in two-stroke, 50-cm 3 moped emissions

    Science.gov (United States)

    Spezzano, Pasquale; Picini, Paolo; Cataldi, Dario

    Gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) concentrations evaluated in the exhaust of 10 two-stroke, 50-cm 3 mopeds belonging to three different levels of emission legislation (EURO-0, EURO-1 and EURO-2) were used to assess the prevalent mechanism driving the gas/particle partitioning of PAHs in moped exhaust. Sampling was performed on a dynamometer bench both during the "cold-start" and the "hot" phases of the ECE-47 driving cycle. Gas and particulate phase PAHs were collected on polyurethane foam (PUF) plugs and 47-mm Pallflex T60A20 filters, respectively, under isokinetic conditions by using sampling probes inserted into the dilution tunnel of a Constant Volume Sampling - Critical Flow Venturi (CVS-CFV) system. The results show that semi-volatile PAHs were predominantly partitioned to the particle phase. The soluble organic fraction (SOF) of the collected particulates ranged between 72 and 98%. Measured total suspended particulate matter normalized partition coefficients ( Kp) were predicted within a factor of 3-5 by assuming absorption into the organic fraction according to a model developed by Harner and Bidleman [Harner, T., Bidleman, T.F., 1998. Octanol-air partition coefficient for describing particle/gas partitioning of aromatic compounds in urban air. Environmental Science & Technology 32, 1494-1502.]. This suggests that the gas/particle partitioning in moped exhaust is mainly driven by the high fraction of organic matter of the emitted particles and that absorption could be the main partitioning mechanism of PAHs.

  16. Gas phase adiabatic electron affinities of cyclopenta-fused polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    Todorov, P.D.; Koper, C.; van Lenthe, J.H.; Jenneskens, L.W.

    2008-01-01

    The B3LYP/DZP++ adiabatic electron affinity (AEA) of nine (non)-alternant polycyclic aromatic hydrocarbons are reported and discussed. Calculations became feasible for molecules this size by projecting out the near-linearly dependent part of the one-electron basis. Non-alternant PAH consisting of an

  17. Potential for aging female Aedes aegypti (Diptera: Culicidae) by gas chromatographic analysis of cuticular hydrocarbons, including a field evaluation.

    Science.gov (United States)

    Desena, M L; Clark, J M; Edman, J D; Symington, S B; Scott, T W; Clark, G G; Peters, T M

    1999-11-01

    Gas chromatography with flame-ionization detection was used to measure the time-associated, quantitative changes in the cuticular hydrocarbons of female Aedes aegypti (L.). Cohorts of unstressed Ae. aegypti, Rockefeller strain, were reared and held at 3 constant temperatures (24, 28, and 30 degrees C). Five females from each cohort were taken at 33 degree-day (DD) intervals from 0 to 231 DD (using 17 degrees C as the threshold temperature). Quantitative changes over time of cuticular hydrocarbons associated with gas chromatographic peaks 1 and 5 were identified as having promise for age grading. The relative abundance of peak 1 (pentacosane) decreased linearly from 0 to 132 DD, whereas peak 5 (nonacosane) increased linearly over the same period. Suboptimal larval conditions (crowded and starved), which resulted in physiological stress (decreased size), had negligible effect on the relative abundance of pentacosane and nonacosane. Additionally, the rate of change in the relative abundance of pentacosane and nonacosane were the same for both a recently colonized Chachoengsao (Thailand) strain of Ae. aegypti compared with the long-colonized Rockefeller (Caribbean) strain over a 0-99 DD interval. Two linear regression models, one based on the relative abundance of pentacosane and the other on the logit transformation of these values, were developed for aging female Ae. aegypti. A blind study using laboratory-reared mosquitoes and a mark-release-recapture experiment using field mosquitoes validated these age-grading models and produced promising results for aging females up to 132 DD (19, 12, and 10 calendar days at 24, 28 and 30 degrees C, respectively). Therefore the regression models, based on the relative abundance of these 2 cuticular hydrocarbons, appeared to be a useful approach for age-grading Ae. aegypti up to at least 12 d of age regardless of environmental conditions (temperature and stress) and population history (origin and colonization time).

  18. A thermodynamic tank model for studying the effect of higher hydrocarbons on natural gas storage in metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, HD; Deria, P; Farha, OK; Hupp, JT; Snurr, RQ

    2015-01-01

    Metal-organic frameworks (MOFs) are promising materials for storing natural gas in vehicular applications. Evaluation of these materials has focused on adsorption of pure methane, although commercial natural gas also contains small amounts of higher hydrocarbons such as ethane and propane, which adsorb more strongly than methane. There is, thus, a possibility that these higher hydrocarbons will accumulate in the MOF after multiple operating (adsorption/desorption) cycles, and reduce the storage capacity. To study the net effect of ethane and propane on the performance of an adsorbed natural gas (ANG) tank, we developed a mathematical model based on thermodynamics and mass balance equations that describes the state of the tank at any instant. The required inputs are the pure-component isotherms, and mixture adsorption data are calculated using the Ideal Adsorbed Solution Theory (IAST). We focused on how the "deliverable energy'' provided by the ANG tank to the engine changed over 200 operating cycles for a sample of 120 MOF structures. We found that, with any MOF, the ANG tank performance monotonically declines during early operating cycles until a "cyclic steady state'' is reached. We determined that the best materials when the fuel is 100% methane are not necessarily the best when the fuel includes ethane and propane. Among the materials tested, some top MOFs are MOF-143 > NU-800 > IRMOF-14 > IRMOF-20 > MIL-100 > NU-125 > IRMOF-1 > NU-111. MOF-143 is predicted to deliver 5.43 MJ L-1 of tank to the engine once the cyclic steady state is reached. The model also provided insights that can assist in future work to discover more promising adsorbent materials for natural gas storage.

  19. Seepage erosion mechanisms of bank collapse: three-dimensional seepage particle mobilization and undercutting

    Science.gov (United States)

    Seepage flow initiates undercutting, similar to development and headward migration of internal gullies, by liquefaction of soil particles, followed by mass wasting of the bank. Although seepage erosion has three-dimensional characteristics, two-dimensional lysimeters have been used in previous resea...

  20. Analysis of wax hydrocarbons in petroleum source rocks from the Damintun depression, eastern China, using high temperature gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Haiping Huang [University of Newcastle upon Tyne (United Kingdom). School of Civil Engineering and Geosciences; Chinese University of Geosciences, Beijing (China). Dept. of Petroleum Geology; Larter, S.R.; Love, G.D. [University of Newcastle upon Tyne (United Kingdom). School of Civil Engineering and Geosciences

    2003-12-01

    environmental conditions, as shown previously [Carlson, R.M.K., Teerman, S.C., Moldowan, J.M., Jacobson, S.R., Chan, E.l., Dorrough, K.S., Sectoo, W.C., Mertani, B., 1993. High temperature gas chromatography of high wax oils. In: Indonesian Petroleum Association, 22nd Annual Convention Proceedings. Jakarta, Indonesian, pp. 483-507. Carlson, R.M.K., Jacobsen, S.R., Moldowan, J.M., Chan E.l., 1994. Potential application of high temperature gas chromatography to Middle Eastern petroleum exploration and production. In: Al-Husseini, M.I. (Ed.), Geo'94, Vol I., Selected Middle East Papers from The Middle East Petroleum Geoscience Conference, 1994; Gulf PetroLink. Manama, Bahrain, pp. 258-2671]. Our study indicates for the first time that Es3 source rocks as well as Es4 facies contain HMVMCS. The distributions of extractable wax hydrocarbons suggest that both Es4 and Es3 members may potentially serve as important parent source rocks for generating waxy petroleum in this region. (author)

  1. RESEARCH ON SEEPAGE MONITORING MODEL OF EARTH-ROCK DAM

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the characteristics of seepage flow in earth-rock dams, a seepage monitoring model was established based on the finite element method for 3-D seepage flow together with observed data and was used to analyze and monitor the seepage of dams. In order to find out and monitor the seepage status of the whole dam, the separation of seepage amount for dam body, dam foundation and side banks was made theoretically by using the model. Practical example shows that the accuracy of computed results is satisfactory and the separation results are more objective.

  2. Performance Evaluations and Quality Validation System for Optical Gas Imaging Cameras That Visualize Fugitive Hydrocarbon Gas Emissions

    Science.gov (United States)

    Optical gas imaging (OGI) cameras have the unique ability to exploit the electromagnetic properties of fugitive chemical vapors to make invisible gases visible. This ability is extremely useful for industrial facilities trying to mitigate product losses from escaping gas and fac...

  3. H-Area Seepage Basins. Third quarter 1990 groundwater quality assessment report

    Energy Technology Data Exchange (ETDEWEB)

    Stejskal, G.

    1990-12-01

    During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

  4. Radionuclides, Metals, and Hydrocarbons in Oil and Gas Operational Discharges and Environmental Samples Associated with Offshore Production Facilities on the Texas/Louisiana Continental Shelf with an Environmental Assessment of Metals and Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Continental Shelf Associates, Inc.

    1999-08-16

    This report presents concentrations of radionuclides, metals, and hydrocarbons in samples of produced water and produced sand from oil and gas production platforms located offshore Texas and Louisiana. Concentrations in produced water discharge plume/receiving water, ambient seawater, sediment, interstitial water, and marine animal tissue samples collected in the vicinity of discharging platforms and reference sites distant from discharges are also reported and discussed. An environmental risk assessment is made on the basis of the concentrations of metals and hydrocarbons determined in the samples.

  5. Radionuclides, Metals, and Hydrocarbons in Oil and Gas Operational Discharges and Environmental Samples Associated with Offshore Production Facilities on the Texas/Louisiana Continental Shelf with an Environmental Assessment of Metals and Hydrocarbons.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    This report presents concentrations of radionuclides, metals, and hydrocarbons in samples of produced water and produced sand from oil and gas production platforms located offshore Texas and Louisiana. concentrations in produced water discharge plume / receiving water, ambient seawater, sediment, interstitial water, and marine animal tissue samples collected in the vicinity of discharging platforms and reference sites distant from discharges are also reported and discussed. An environmental risk assessment is made on the basis of the concentration of metals and hydrocarbons determined in the samples.

  6. Gas-liquid-liquid equilibria in mixtures of water, light gases, and hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Chao, K.C.

    1990-01-01

    Phase equilibrium in mixtures of water + light gases and water + heavy hydrocarbons has been investigated with the development of new local composition theory, new equations of state, and new experimental data. The preferential segregation and orientation of molecules due to different energies of molecular interaction has been simulated with square well molecules. Extensive simulation has been made for pure square well fluids and mixtures to find the local composition at wide ranges of states. A theory of local composition has been developed and an equation of state has been obtained for square well fluids. The new local composition theory has been embedded in several equations of state. The pressure of water is decoupled into a polar pressure and non-polar pressure according to the molecular model of water of Jorgensen et al. The polar pressure of water is combined with the BACK equation for the general description of polar fluids and their mixtures. Being derived from the steam table, the Augmented BACK equation is particularly suited for mixtures of water + non-polar substances such as the hydrocarbons. The hydrophobic character of the hydrocarbons had made their mixtures with water a special challenge. A new group contribution equation of state is developed to describe phase equilibrium and volumetric behavior of fluids while requiring only to know the molecular structure of the components. 15 refs., 1 fig.

  7. Analytical method validation of GC-FID for the simultaneous measurement of hydrocarbons (C2-C4 in their gas mixture

    Directory of Open Access Journals (Sweden)

    Oman Zuas

    2016-09-01

    Full Text Available An accurate gas chromatography coupled to a flame ionization detector (GC-FID method was validated for the simultaneous analysis of light hydrocarbons (C2-C4 in their gas mixture. The validation parameters were evaluated based on the ISO/IEC 17025 definition including method selectivity, repeatability, accuracy, linearity, limit of detection (LOD, limit of quantitation (LOQ, and ruggedness. Under the optimum analytical conditions, the analysis of gas mixture revealed that each target component was well-separated with high selectivity property. The method was also found to be precise and accurate. The method linearity was found to be high with good correlation coefficient values (R2 ≥ 0.999 for all target components. It can be concluded that the GC-FID developed method is reliable and suitable for determination of light C2-C4 hydrocarbons (including ethylene, propane, propylene, isobutane, and n-butane in their gas mixture. The validated method has successfully been applied to the estimation of hydrocarbons light C2-C4 hydrocarbons in natural gas samples, showing high performance repeatability with relative standard deviation (RSD less than 1.0% and good selectivity with no interference from other possible components could be observed.

  8. Quantification of Seepage in Groundwater Dependent Wetlands

    DEFF Research Database (Denmark)

    Johansen, Ole; Beven, Keith; Jensen, Jacob Birk

    2017-01-01

    Restoration and management of groundwater dependent wetlands require tools for quantifying the groundwater seepage process. A method for determining point estimates of the groundwater seepage based on water level observations is tested. The study is based on field data from a Danish rich fen...... to investigate the uncertainties of parameters and model results. Two different model structures are presented. One is using the physically based model code HYDRUS nek et al. 2009) which solves the 1D unsaturated flow problem. In this case five parameters from the Van Genuchten retention model are examined...... has been predicted. Both models suffer from the fundamental problem that no reliable observations for the predicted variable (seepage rate) exist. Thus the trust in the model therefore depends on the ability to reproduce water level observations. Assuming that the results can be fully validated...

  9. Interlaboratory tests to identify irradiation treatment of various foods via gas chromatographic detection of hydrocarbons, ESR spectroscopy and TL analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, G.A.; Helle, N.; Schulzki, G.; Linke, B.; Spiegelberg, A.; Mager, M.; Boegl, K.W. [BgVV - Federal Inst. for Health Protection of Consumers and Veterinary Medicine, Berlin (Germany)

    1996-12-31

    The gas chromatographic (GC) analysis of radiation-induced volatile hydrocarbons (HC) and 2-alkylcyclobutanones, the ESR spectroscopic detection of radiation-specific radicals and the thermoluminescence (TL) analysis of silicate mineral are the most important methods for identification of irradiated foods. After successful performance in interlaboratory studies on meat products, fish, spices, herbs and shells of nuts, all or some of these methods have been approved by national authorities in Germany and the United Kingdom. Recently, draft European Standards have been elaborated for approval by member states of the European Committee for Standardization (CEN). Several research laboratories have shown that these methods can be applied to various foods not yet tested in collaborative studies. However, for an effective application in food control it is necessary to prove their suitability in interlaboratory studies. Therefore, in 1993/94, various interlaboratory tests were organised by the BgVV. In an ESR spectroscopic test, shrimps and paprika powder were examined. Shrimps were also the subject of examination in a TL test. Finally, GC detection of radiation-induced hydrocarbons in the fat fraction of foods was used in another test to identify irradiated Camembert, avocado, papaya and mango. In the following paper, results of the interlaboratory tests are summarised. Detailed reports are published by this institute. (author).

  10. Determination of polycyclic aromatic hydrocarbons in soy isoflavone nutraceutical products by gas chromatography coupled to triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Ruiz-Delgado, Ana; Martínez-Domínguez, Gerardo; Romero-González, Roberto; López-Ruiz, Rosalía; Frenich, Antonia Garrido

    2016-02-01

    Thirteen polycyclic aromatic hydrocarbons have been determined in soy-based nutraceutical products. First, an optimization of extraction procedure was performed, and a solid-liquid extraction assisted by sonication and a dilute and shoot procedure were compared, selecting the dilute and shoot approach for the extraction of target compounds, utilizing a mixture of acetone/n-hexane (1:1 v/v) as extractant solvent. After this, a clean-up step was needed bearing in mind the complexity of these matrices. Dispersive solid-phase extraction, using a mixture of C18 and Zr-Sep+ (25 mg/mL each) was used. The separation was achieved by gas chromatography and detection with triple quadrupole tandem mass spectrometry. For quantification purposes, matrix-matched calibration was used. The validation was applied at three concentration levels (20, 100 and 250 μg/kg), obtaining recoveries between 70 and 120% and precision values equal to or lower than 23%. Limits of detection and quantification were below 8 and 20 μg/kg, respectively. The method was applied in 11 samples, detecting five polycyclic aromatic hydrocarbons at concentrations ranging from 4.1 to 18.5 μg/kg.

  11. Bio-testing integral toxicity of corrosion inhibitors, biocides and oil hydrocarbons in oil-and gas-processing industry

    Energy Technology Data Exchange (ETDEWEB)

    Chugunov, V.A.; Kholodenko, V.P.; Irkhina, I.A.; Fomchenkov, V.M.; Novikov, I.A. [State Research Center for Applied Microbiology, Obolensk, Moscow (Russian Federation)

    2004-07-01

    In recent years bioassays have been widely used for assessing levels of contamination of the environment. This is due to the fact that test-organisms provide a general response to toxicants present in samples. Based on microorganisms as test objects, it is possible to develop cheap, sensitive and rapid assays to identify environmental xenobiotics and toxicants. The objective of the research was to develop different microbiological assays for assessing integral toxicity of water environments polluted with corrosion inhibitors, biocides and hydrocarbons in oil- and gas-processing industry. Bio-luminescent, electro-orientational, osmo-optic and microorganism reducing activity assays were used for express evaluation of integral toxicity. They are found to determine promptly integral toxicity of water environments containing various pollutants (oil, oil products, corrosion inhibitors, biocides). Results conclude that the assays may be used for analyzing integral toxicity of water polluted with hydrocarbons, as well as for monitoring of water changes as a result of biodegradation of pollutants by microorganisms and their associations. Using a kit of different assays, it is also possible to evaluate ecological safety of biocides, corrosion inhibitors, and their compositions. Bioassays used as a kit are more effective than each assay individually, allowing one to get complete characterization of a reaction of bacterial test organisms to different environments. (authors)

  12. Analysis of non-methane hydrocarbon data from a monitoring station affected by oil and gas development in the Eagle Ford shale, Texas

    Directory of Open Access Journals (Sweden)

    Gunnar W. Schade

    2016-03-01

    Full Text Available Abstract Within the last decade, unconventional oil and gas exploration in the US has become a new source of atmospheric hydrocarbons. Although a geographically dispersed source, field measurements in and downwind of a number of shale basins demonstrate the impact exploration activities have on ambient levels of hydrocarbons. Due to concerns related to ozone production, regulatory agencies are adding monitoring stations to better understand the potential influence of emissions from areas with increased oil and gas related activities. The Eagle Ford shale in south Texas is a rapidly developing shale play producing both oil and natural gas, providing 10% and 5% of US domestic oil and gas production, respectively, in 2013. We analyzed the first year of measurements from a newly established monitoring site at its central north edge. The data reveal median ethane mixing ratios—used as a marker for oil and gas exploration related emissions—at five times its typical clean air background. Ethane mixing ratios above ten times the background occurred regularly. Saturated hydrocarbons with likely origin in oil and gas exploration explain half of the data set’s variability. They dominate OH radical reactivity at levels both similar to other shale areas and similar to Houston’s ship channel area a decade ago. Air advecting slowly across the shale area from east-southeast and southwest directions shows the most elevated hydrocarbon concentrations, and evidence is presented linking elevated alkene abundances to flaring in the shale area. A case study is presented linking high emissions from an upwind facility to hydrocarbon plumes observed at the monitor.

  13. Evaluation of environmental levels of aromatic hydrocarbons in gasoline service stations by gas chromatography.

    Science.gov (United States)

    Periago, J F; Zambudio, A; Prado, C

    1997-08-22

    The volume of gasoline sold in refuelling operations and the ambient temperature, can increase significantly the environmental levels of aromatic hydrocarbon vapours and subsequently, the occupational risk of gasoline service station attendants, specially in the case of benzene. We have evaluated the occupational exposure to aromatic hydrocarbons by means of personal-breathing-zone samples of gasoline vapours in a service station attendant population. This evaluation was carried out using diffusive samplers, in two periods at quite different temperatures (March and July). A significant relationship between the volume of gasoline sold during the shift and the ambient concentration of benzene, toluene, and xylenes was found for each worker sampled. Furthermore a significant difference was found between the time-weighted average concentration of aromatic compounds measured in March, with ambient temperatures of 14-15 degrees C and July, with temperatures of 28-30 degrees C. In addition, 20% of the population sampled in the last period were exposed to a time-weighted average concentration of benzene above the proposed Threshold Limit Value of 960 micrograms/m(3) of the American Conference of Governmental Industrial Hygienists (ACGIH).

  14. Raman Gas Species Measurements in Hydrocarbon-Fueled Rocket Engine Injector Flows

    Science.gov (United States)

    Wehrmeyer, Joseph; Hartfield, Roy J., Jr.; Trinh, Huu P.; Dobson, Chris C.; Eskridge, Richard H.

    2000-01-01

    Rocket engine propellent injector development at NASA-Marshall includes experimental analysis using optical techniques, such as Raman, fluorescence, or Mie scattering. For the application of spontaneous Raman scattering to hydrocarbon-fueled flows a technique needs to be developed to remove the interfering polycyclic aromatic hydrocarbon fluorescence from the relatively weak Raman signals. A current application of such a technique is to the analysis of the mixing and combustion performance of multijet, impinging-jet candidate fuel injectors for the baseline Mars ascent engine, which will burn methane and liquid oxygen produced in-situ on Mars to reduce the propellent mass transported to Mars for future manned Mars missions. The Raman technique takes advantage of the strongly polarized nature of Raman scattering. It is shown to be discernable from unpolarized fluorescence interference by subtracting one polarized image from another. Both of these polarized images are obtained from a single laser pulse by using a polarization-separating calcite rhomb mounted in the imaging spectrograph. A demonstration in a propane-air flame is presented, as well as a high pressure demonstration in the NASA-Marshall Modular Combustion Test Artice, using the liquid methane-liquid oxygen propellant system

  15. Influence of Gas Feed Composition and Pressure on the Catalytic Conversion of CO2 to Hydrocarbons Using a Traditional Cobalt-Based Fischer-Tropsch Catalyst

    Science.gov (United States)

    2009-06-25

    availability. Fuel independence would alleviate uncertainties in the world market supply of oil along with commercial fluctuations in price. In addition...this supply by supporting the development of synthetic hydrocarbon fuel from the vast natural resources, such as coal, shale, gas hydrates, and CO2...product a day by steam-reforming coal to generate syngas for the FT process.5 A water-gas shift is needed to obtain a 2:1 ratio of hydrogen/carbon

  16. D-area oil seepage basin bioventing optimization test plan

    Energy Technology Data Exchange (ETDEWEB)

    Berry, C.J.; Radway, J.C.; Alman, D.; Hazen, T.C.

    1998-12-31

    The D Area Oil Seepage Basin (DOSB) was used from 1952 to 1975 for disposal of petroleum-based products (waste oils), general office and cafeteria waste, and apparently some solvents [trichloroethylene (TCE)/tetrachloroethylene (PCE)]. Numerous analytical results have indicated the presence of TCE and its degradation product vinyl chloride in groundwater in and around the unit, and of petroleum hydrocarbons in soils within the unit. The DOSB is slated for additional assessment and perhaps for environmental remediation. In situ bioremediation represents a technology of demonstrated effectiveness in the reclamation of sites contaminated with petroleum hydrocarbons and chlorinated solvents, and has been retained as an alternative for the cleanup of the DOSB. The Savannah River Site is therefore proposing to conduct a field treatability study designed to demonstrate and optimize the effectiveness of in situ microbiological biodegradative processes at the DOSB. The introduction of air and gaseous nutrients via two horizontal injection wells (bioventing) is expected to enhance biodegradation rates of petroleum components and stimulate microbial degradation of chlorinated solvents. The data gathered in this test will allow a determination of the biodegradation rates of contaminants of concern in the soil and groundwater, allow an evaluation of the feasibility of in situ bioremediation of soil and groundwater at the DOSB, and provide data necessary for the functional design criteria for the final remediation system.

  17. D-area oil seepage basin bioventing optimization test plan

    Energy Technology Data Exchange (ETDEWEB)

    Berry, C.J.; Radway, J.C.; Alman, D.; Hazen, T.C.

    1998-12-31

    The D Area Oil Seepage Basin (DOSB) was used from 1952 to 1975 for disposal of petroleum-based products (waste oils), general office and cafeteria waste, and apparently some solvents [trichloroethylene (TCE)/tetrachloroethylene (PCE)]. Numerous analytical results have indicated the presence of TCE and its degradation product vinyl chloride in groundwater in and around the unit, and of petroleum hydrocarbons in soils within the unit. The DOSB is slated for additional assessment and perhaps for environmental remediation. In situ bioremediation represents a technology of demonstrated effectiveness in the reclamation of sites contaminated with petroleum hydrocarbons and chlorinated solvents, and has been retained as an alternative for the cleanup of the DOSB. The Savannah River Site is therefore proposing to conduct a field treatability study designed to demonstrate and optimize the effectiveness of in situ microbiological biodegradative processes at the DOSB. The introduction of air and gaseous nutrients via two horizontal injection wells (bioventing) is expected to enhance biodegradation rates of petroleum components and stimulate microbial degradation of chlorinated solvents. The data gathered in this test will allow a determination of the biodegradation rates of contaminants of concern in the soil and groundwater, allow an evaluation of the feasibility of in situ bioremediation of soil and groundwater at the DOSB, and provide data necessary for the functional design criteria for the final remediation system.

  18. High-temperature two-dimensional gas chromatography of hydrocarbons up to nC60 for analysis of vacuum gas oils.

    Science.gov (United States)

    Dutriez, Thomas; Courtiade, Marion; Thiébaut, Didier; Dulot, Hugues; Bertoncini, Fabrice; Vial, Jérôme; Hennion, Marie-Claire

    2009-04-03

    In a tense energetic context, the characterization of heavy petroleum fractions becomes essential. Conventional comprehensive two-dimensional gas chromatography (2D-GC or GCxGC) is widely used for middle distillates analysis, but only a few applications are devoted to these heavier fractions. In this paper, it is shown how the optimization of GCxGC separation allowed the determination of suitable high-temperature (HT) conditions, adjusting column properties and operating conditions. 2D separations were evaluated using 2D separation criteria and a new concept of 2D asymmetry (As(2D)). New HT conditions allowed the extension of GCxGC range of applications to heavier hydrocarbons, up to nC(60). A first application of high-temperature two-dimensional gas chromatography (HT-2D-GC) to a full vacuum gas oil (VGO) feed stock is described. Comparisons with other standardized methods illustrate the high potential of HT-2D-GC for heavy fractions analysis.

  19. A Simulator for a Hydrocarbon Ramrocket Fuel Gas Generator - First Phase Development

    Science.gov (United States)

    1989-05-01

    Australian Airlines, Library Qantas Airways Limited Gas & Fuel Corporation of Vic., Manager Scientific Services SEC of Vic., Herman Research Laboratory...EXHAUST SAMPLING AND ANALYSIS 8 7.1 Solid Products 9 7.1.1 Probe System 9 7.1.2 Wet Filtering 9 7.1.3 Dry Filtering 10 7.2 Gaseous Products 10 7.2.1 Gas...Sampling System 10 7.2.2 Gas Chromatography 11 8. OBSERVATIONS OF TEST HARDWARE PERFORMANCE 11 9. RESULTS AND DISCUSSION 13 9.1 Analysis of Zaccardi

  20. Using Ramped Pyrolysis - Gas Chromatography - Mass Spectrometry to Evaluate Petroleum Hydrocarbons Following the Deepwater Horizon Oil Spill

    Science.gov (United States)

    Evans, M.; Rosenheim, B. E.; Bacosa, H. P.; Liu, J.; Liu, Z.

    2016-02-01

    In summer of 2010, the Deepwater Horizon oil spill polluted hundreds of miles of coastline along the Gulf of Mexico. A combination of human-mediated and natural weathering processes then altered the chemical composition (i.e. toxicity) of this spilled crude oil over time and space. One of the most important, yet challenging, aspects of oil spill science is to quantify these chemical changes in natural environments. In this study, we develop ramped pyrolysis - gas chromatography - mass spectrometry (Py-GC-MS) to address this challenge. In this technique, 0.1mg of freeze-dried sample is pyrolyzed over a gradual temperature ramp (50-650°C). The eluded gas is cold-trapped over different thermal ranges (a.k.a. thermal slicing) and each range is individually analyzed via GC-MS, yielding quantifiable, compound-specific results. Py-GC-MS with thermal slicing has never been used for petroleum hydrocarbon analysis, but it has many advantages - it uses minimal sample, is time efficient and does not require sample preparation (minimizing compound loss and increasing the analytical window). During development of this method, we analyzed oiled sediments and tar collected on Grand Isle, Louisiana from 2010-2012. We quantified n-alkane (C10-C38), polycyclic aromatic hydrocarbon (PAH) and hopane content and confirmed these results with traditional solvent extraction, silica gel fractionation and mass spectrometry. Overall, we found rapid depletion of n-alkanes and PAHs (>90% depletion) in all samples within one year of Deepwater Horizon. After this, n-alkanes were almost 100% depleted by 2012, while PAH degradation continued to a maximum total degradation of 99% and 98% in sediment and tar, respectively. This not only describes the fate of petroleum compounds in salt marshes and beach deposits over time, but also complements previous radiocarbon studies of the same samples showing different rates of degradation in different micro-environments. In addition, the results presented

  1. Performance Evaluation and Quality Validation System for Optical Gas Imaging Cameras that Visualize Fugitive Hydrocarbon Gas Emissions

    Science.gov (United States)

    A U.S. EPA team, consisting of the Office of Research and Development and Region 6 (Dallas) and Region 8 (Denver), deployed passive-diffusive sorbent tubes as part of a method evaluation study around one oil and natural gas production pad in both the Barnett Shale Basin in Texas ...

  2. Plasma devices for hydrocarbon reformation

    KAUST Repository

    Cha, Min Suk

    2017-02-16

    Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured to be submerged in the liquid. The plasma plume from the plasma torch can cause reformation of the hydrocarbon. The device can use a variety of plasma torches that can be arranged in a variety of positions in the liquid container. The devices can be used for the reformation of gaseous hydrocarbons and/or liquid hydrocarbons. The reformation can produce methane, lower hydrocarbons, higher hydrocarbons, hydrogen gas, water, carbon dioxide, carbon monoxide, or a combination thereof.

  3. Improvement of mineral oil saturated and aromatic hydrocarbons determination in edible oil by liquid-liquid-gas chromatography with dual detection.

    Science.gov (United States)

    Zoccali, Mariosimone; Barp, Laura; Beccaria, Marco; Sciarrone, Danilo; Purcaro, Giorgia; Mondello, Luigi

    2016-02-01

    Mineral oils, which are mainly composed of saturated hydrocarbons and aromatic hydrocarbons, are widespread food contaminants. Liquid chromatography coupled to gas chromatography with flame ionization detection represents the method of choice to determine these two families. However, despite the high selectivity of this technique, the presence of olefins (particularly squalene and its isomers) in some samples as in olive oils, does not allow the correct quantification of the mineral oil aromatic hydrocarbons fraction, requiring additional off-line tools to eliminate them. In the present research, a novel on-line liquid chromatography coupled to gas chromatography method is described for the determination of hydrocarbon contamination in edible oils. Two different liquid chromatography columns, namely a silica one (to retain the bulk of the matrix) and a silver-ion one (which better retains the olefins), were coupled in series to obtain the mineral oil aromatic hydrocarbons hump free of interfering peaks. Furthermore, the use of a simultaneous dual detection, flame ionization detector and triple quadrupole mass spectrometer allowed us not only to quantify the mineral oil contamination, but also to evaluate the presence of specific markers (i.e. hopanes) to confirm the petrogenic origin of the contamination.

  4. Structure and chemistry of the heteronuclear oxo-cluster [VPO4]•+: a model system for the gas-phase oxidation of small hydrocarbons.

    Science.gov (United States)

    Dietl, Nicolas; Wende, Torsten; Chen, Kai; Jiang, Ling; Schlangen, Maria; Zhang, Xinhao; Asmis, Knut R; Schwarz, Helmut

    2013-03-06

    The heteronuclear oxo-cluster [VPO4](•+) is generated via electrospray ionization and investigated with respect to both its electronic structure as well as its gas-phase reactivity toward small hydrocarbons, thus permitting a comparison to the well-known vanadium-oxide cation [V2O4](•+). As described in previous studies, the latter oxide exhibits no or just minor reactivity toward small hydrocarbons, such as CH4, C2H6, C3H8, n-C4H10, and C2H4, while substitution of one vanadium by a phosphorus atom yields the reactive [VPO4](•+) ion; the latter brings about oxidative dehydrogenation (ODH) of saturated hydrocarbons, e.g., propane and butane as well as oxygen-atom transfer (OAT) to unsaturated hydrocarbons, e.g. ethene, at thermal conditions. Further, the gas-phase structure of [VPO4](•+) is determined by IR photodissociation spectroscopy and compared to that of [V2O4](•+). DFT calculations help to elucidate the reaction mechanism. The results underline the crucial role of phosphorus in terms of C-H bond activation of hydrocarbons by mixed VPO clusters.

  5. Gas-phase Reactions of Polycyclic Aromatic Hydrocarbon Anions with Molecules of Interstellar Relevance

    Science.gov (United States)

    Demarais, Nicholas J.; Yang, Zhibo; Martinez, Oscar; Wehres, Nadine; Snow, Theodore P.; Bierbaum, Veronica M.

    2012-02-01

    We have studied reactions of small dehydrogenated polycyclic aromatic hydrocarbon anions with neutral species of interstellar relevance. Reaction rate constants are measured at 300 K for the reactions of phenide (C6H- 5), naphthalenide (C10H- 7), and anthracenide (C14H- 9) with atomic H, H2, and D2 using a flowing afterglow-selected ion flow tube instrument. Reaction rate constants of phenide with neutral molecules (CO, O2, CO2, N2O, C2H2, CH3OH, CH3CN, (CH3)2CO, CH3CHO, CH3Cl, and (CH3CH2)2O) are also measured under the same conditions. Experimental measurements are accompanied by ab initio calculations to provide insight into reaction pathways and enthalpies. Our measured reaction rate constants should prove useful in the modeling of astrophysical environments, particularly when applied to dense regions of the interstellar and circumstellar medium.

  6. Influence of oil and gas emissions on ambient atmospheric non-methane hydrocarbons in residential areas of Northeastern Colorado

    Directory of Open Access Journals (Sweden)

    Chelsea R. Thompson

    2014-11-01

    Full Text Available Abstract The Northern Front Range (NFR region of Colorado has experienced rapid expansion of oil and gas extraction from shale and tight sands reservoirs in recent years due to advances in hydraulic fracturing technology, with over 25,000 wells currently in operation. This region has also been designated as a federal ozone non-attainment area by the U.S. EPA. High ozone levels are a significant health concern, as are potential health impacts from chronic exposure to primary emissions of non-methane hydrocarbons (NMHC for residents living near wells. From measurements of ambient atmospheric NMHC present in residential areas located in close proximity to wells in Erie, Colorado, we find that mean mole fractions of the C2–C5 alkanes are enhanced by a factor of 18–77 relative to the regional background, and present at higher levels than typically found in large urban centers. When combined with NMHC observations from downtown Denver and Platteville, it is apparent that these compounds are elevated across the NFR, with highest levels within the Greater Wattenberg Gas Field. This represents a large area source for ozone precursors in the NFR. The BTEX aromatic compounds in Erie were comparable to (e.g., benzene or lower than (e.g., toluene, ethylbenzene, xylene in large urban centers, however, benzene was significantly higher in Platteville, and within the range of chronic health-based exposure levels. An initial look at comparisons with data sets from previous years reveal that ambient levels for oil and gas-related NMHC in Erie, as well as further downwind in Boulder, have not decreased, but appear to have been increasing, despite tightening of emissions standards for the oil and gas industries in 2008.

  7. Role of glyoxal in SOA formation from aromatic hydrocarbons: gas-phase reaction trumps reactive uptake

    Directory of Open Access Journals (Sweden)

    S. Nakao

    2011-11-01

    Full Text Available This study evaluates the significance of glyoxal acting as an intermediate species leading to SOA formation from aromatic hydrocarbon photooxidation under humid conditions. Rapid SOA formation from glyoxal uptake onto aqueous (NH42SO4 seed particles is observed; however, glyoxal did not partition to SOA or SOA coated aqueous seed during all aromatic hydrocarbon experiments (RH up to 80%. Glyoxal is found to only influence SOA formation by raising hydroxyl (OH radical concentrations. Four experimental approaches supporting this conclusion are presented in this paper: (1 increased SOA formation and decreased SOA volatility in the toluene + NOx photooxidation system with additional glyoxal was reproduced by matching OH radical concentrations through H2O2 addition; (2 glyoxal addition to SOA seed formed from toluene + NOx photooxidation did not increase observed SOA volume; (3 SOA formation from toluene + NOx photooxidation with and without deliquesced (NH42SO4 seed resulted in similar SOA growth, consistent with a coating of SOA preventing glyoxal uptake onto deliquesced (NH42SO4 seed; and (4 the fraction of a C4H9+ fragment (observed by Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer, HR-ToF-AMS from SOA formed by 2-tert-butylphenol (BP oxidation was unchanged in the presence of additional glyoxal despite enhanced SOA formation. This study suggests that glyoxal uptake onto aerosol is minor when the surface (and near-surface of aerosols are primarily composed of secondary organic compounds.

  8. GLOBAL PROSPECTS OF SYNTHETIC DIESEL FUEL PRODUCED FROM HYDROCARBON RESOURCES IN OIL&GAS EXPORTING COUNTRIES

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2007-12-01

    Full Text Available Production of synthetic diesel fuel through Fischer-Tropsch process is a well known technology which dates from II World War, when Germany was producing transport fuel from coal. This process has been further improved in the South Africa due to period of international isolation. Today, with high crude oil market cost and increased demand of energy from China and India, as well as global ecological awareness and need to improve air quality in urban surroundings, many projects are being planned regarding production of synthetic diesel fuel, known as GTL (Gas To Liquid. Most of the future GTL plants are planned in oil exporting countries, such are Qatar and Nigeria, where natural gas as by-product of oil production is being flared, losing in that way precious energy and profit. In that way, otherwise flared natural gas, will be transformed into synthetic diesel fuel which can be directly used in all modern diesel engines. Furthermore, fossil fuel transportation and distribution technology grid can be used without any significant changes. According to lower emissions of harmful gasses during combustion than fossil diesel, this fuel could in the future play a significant part of EU efforts to reach 23% of alternative fuel share till 2020., which are now mostly relied on biodiesel, LPG (liquefied petroleum gas and CNG (compressed natural gas.

  9. Research Progress and Development on Seepage Mechanics%渗流力学进展与前沿

    Institute of Scientific and Technical Information of China (English)

    李明川; 姚军; 葛家理

    2012-01-01

    Based on the well-known Darcy seepage theory of France H. Darcy engineer in 1856, the Paper reviewed the cavalcade: from Darcy to non-Darcy seepage, from Newtonian fluid to non-Newtonian fluid seepage and from continuum to discontinuous of seepage mechanics. Summarization induces the applied developing course in petroleum industry: reservoir of migration, gathering and formation in exploration activity; reservoir of recognition, exploitation and recreation in oil/gas field development; oil/gas house of geologic framework, water pollution, alkaline soil and 3rd production in oil/gas preservation and transportation. Prospects research the leading edge and challenge of multi-field coupling seepage, macro- microscopic seepage and multi-scale seepage on seepage mechanics binding traditional seepage theory and burgeoning science and technology called on the advanced methods of physics and mathematics. With the science and technology hasty development, more modernism and technology will prompt the theory of seepage mechanics more evaluative.%基于1856年法国工程师H.Darcy的著名Darcy渗流理论,回顾了渗流力学由达西渗流朝向非达西渗流、牛顿流体渗流朝向非牛顿渗流、连续介质渗流朝向非连续介质渗流方向的发展进程.总结归纳了渗流力学在石油工业中的应用发展历程:渗流力学在油气运移、聚集和形成油藏的油气勘探中的应用;渗流力学在认识、开发及改造油气藏的油气田开发的应用;渗流力学在油气库的地质结构、水污染、盐碱化以及三次采油的油气储运中的应用.展望了借助于先进的物理、数学方法,将传统的渗流力学理论与新兴科学技术融合发展起来的多场耦合渗流、宏微渗流和多尺度渗流理论的研究前沿与挑战.随着科学技术的飞速发展,更多现代方法和技术将会推动着渗流力学理论进一步发展.

  10. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

    Science.gov (United States)

    Mau, S.; Römer, M.; Torres, M. E.; Bussmann, I.; Pape, T.; Damm, E.; Geprägs, P.; Wintersteller, P.; Hsu, C.-W.; Loher, M.; Bohrmann, G.

    2017-02-01

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02-7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.

  11. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

    Science.gov (United States)

    Mau, S.; Römer, M.; Torres, M. E.; Bussmann, I.; Pape, T.; Damm, E.; Geprägs, P.; Wintersteller, P.; Hsu, C.-W.; Loher, M.; Bohrmann, G.

    2017-01-01

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming. PMID:28230189

  12. Crosslinked structurally-tuned polymeric ionic liquids as stationary phases for the analysis of hydrocarbons in kerosene and diesel fuels by comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Zhang, Cheng; Park, Rodney A; Anderson, Jared L

    2016-04-01

    Structurally-tuned ionic liquids (ILs) have been previously applied as the second dimension column in comprehensive two-dimensional gas chromatography (GC×GC) and have demonstrated high selectivity in the separation of individual aliphatic hydrocarbons from other aliphatic hydrocarbons. However, the maximum operating temperatures of these stationary phases limit the separation of analytes with high boiling points. In order to address this issue, a series of polymeric ionic liquid (PIL)-based stationary phases were prepared in this study using imidazolium-based IL monomers via in-column free radical polymerization. The IL monomers were functionalized with long alkyl chain substituents to provide the needed selectivity for the separation of aliphatic hydrocarbons. Columns were prepared with different film thicknesses to identify the best performing stationary phase for the separation of kerosene. The bis[(trifluoromethyl)sulfonyl]imide ([NTf2](-))-based PIL stationary phase with larger film thickness (0.28μm) exhibited higher selectivity for aliphatic hydrocarbons and showed a maximum allowable operating temperature of 300°C. PIL-based stationary phases containing varied amount of IL-based crosslinker were prepared to study the effect of the crosslinker on the selectivity and thermal stability of the resulting stationary phase. The optimal resolution of aliphatic hydrocarbons was achieved when 50% (w/w) of crosslinker was incorporated into the PIL-based stationary phase. The resulting stationary phase exhibited good selectivity for different groups of aliphatic hydrocarbons even after being conditioned at 325°C. Finally, the crosslinked PIL-based stationary phase was compared with SUPELCOWAX 10 and DB-17 columns for the separation of aliphatic hydrocarbons in diesel fuel. Better resolution of aliphatic hydrocarbons was obtained when employing the crosslinked PIL-based stationary phase as the second dimension column.

  13. Lipidic ionic liquid stationary phases for the separation of aliphatic hydrocarbons by comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Nan, He; Zhang, Cheng; O'Brien, Richard A; Benchea, Adela; Davis, James H; Anderson, Jared L

    2017-01-20

    Lipidic ionic liquids (ILs) possessing long alkyl chains as well as low melting points have the potential to provide unique selectivity as well as wide operating ranges when used as stationary phases in gas chromatography. In this study, a total of eleven lipidic ILs containing various structural features (i.e., double bonds, linear thioether chains, and cyclopropanyl groups) were examined as stationary phases in comprehensive two dimensional gas chromatography (GC×GC) for the separation of nonpolar analytes in kerosene. N-alkyl-N'-methyl-imidazolium-based ILs containing different alkyl side chains were used as model structures to investigate the effects of alkyl moieties with different structural features on the selectivities and operating temperature ranges of the IL-based stationary phases. Compared to a homologous series of ILs containing saturated side chains, lipidic ILs exhibit improved selectivity toward the aliphatic hydrocarbons in kerosene. The palmitoleyl IL provided the highest selectivity compared to all other lipidic ILs as well as the commercial SUPELCOWAX 10 column. The linoleyl IL containing two double bonds within the alkyl side chain showed the lowest chromatographic selectivity. The lipidic IL possessing a cyclopropanyl group within the alkyl moiety exhibited the highest thermal stability. The Abraham solvation parameter model was used to evaluate the solvation properties of the lipidic ILs. This study provides the first comprehensive examination into the relation between lipidic IL structure and the resulting solvation characteristics. Furthermore, these results establish a basis for applying lipidic ILs as stationary phases for solute specific separations in GC×GC.

  14. Changes in liquid water alter nutrient bioavailability and gas diffusion in frozen antarctic soils contaminated with petroleum hydrocarbons.

    Science.gov (United States)

    Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas

    2012-02-01

    Bioremediation has been used to remediate petroleum hydrocarbon (PHC)-contaminated sites in polar regions; however, limited knowledge exists in understanding how frozen conditions influence factors that regulate microbial activity. We hypothesized that increased liquid water (θ(liquid) ) would affect nutrient supply rates (NSR) and gas diffusion under frozen conditions. If true, management practices that increase θ(liquid) should also increase bioremediation in polar soils by reducing nutrient and oxygen limitations. Influence of θ(liquid) on NSR was determined using diesel-contaminated soil (0-8,000 mg kg(-1)) from Casey Station, Antarctica. The θ(liquid) was altered between 0.007 and 0.035 cm(3) cm(-3) by packing soil cores at different bulk densities. The nutrient supply rate of NH 4+ and NO 3-, as well as gas diffusion coefficient, D(s), were measured at two temperatures, 21°C and -5°C, to correct for bulk density effects. Freezing decreased NSR of both NH 4+ and NO 3-, with θ(liquid) linked to nitrate and ammonia NSR in frozen soil. Similarly for D(s), decreases due to freezing were much more pronounced in soils with low θ(liquid) compared to soils with higher θ(liquid) contents. Additional studies are needed to determine the relationship between degradation rates and θ(liquid) under frozen conditions.

  15. Adsorption isotherms of some alkyl aromatic hydrocarbons and surface energies on partially dealuminated Y faujasite zeolite by inverse gas chromatography.

    Science.gov (United States)

    Kondor, Anett; Dallos, András

    2014-10-03

    Adsorption isotherm data of some alkyl aromatic hydrocarbons (benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene) measured in the temperature range of 423-523K on a partially dealuminated faujasite type DAY F20 zeolite by inverse gas chromatography are presented in this work. The temperature dependent form of Tóth's equation has been fitted to the multiple temperature adsorption isotherms of benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene with standard deviations of 4.6, 5.0, 5.9, 4.3, 5.1 and 6.3mmolkg(-1) and coefficients of determinations (r(2)) of 0.977, 0.971, 0.974, 0.975, 0.991 and 0.991, respectively. The gas-solid equilibria and modeling were interpreted on the basis of the interfacial properties of the zeolite, by dispersive, specific and total surface energy heterogeneity profiles and distributions of the adsorbent measured by surface energy analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Polycyclic aromatic hydrocarbons in air on small spatial and temporal scales - II. Mass size distributions and gas-particle partitioning

    Science.gov (United States)

    Lammel, Gerhard; Klánová, Jana; Ilić, Predrag; Kohoutek, Jiří; Gasić, Bojan; Kovacić, Igor; Škrdlíková, Lenka

    2010-12-01

    Polycyclic aromatic hydrocarbons (PAHs) were measured together with inorganic air pollutants at two urban sites and one rural background site in the Banja Luka area, Bosnia and Hercegovina, during 72 h in July 2008 using a high time resolution (5 samples per day) with the aim to study gas-particle partitioning, aerosol mass size distributions and to explore the potential of a higher time resolution (4 h-sampling). In the particulate phase the mass median diameters of the PAHs were found almost exclusively in the accumulation mode (0.1-1.0 μm of size). These were larger for semivolatile PAHs than for non-volatile PAHs. Gas-particle partitioning of semivolatile PAHs was strongly influenced by temperature. The results suggest that the Junge-Pankow model is inadequate to explain the inter-species variation and another process must be significant for phase partitioning which is less temperature sensitive than adsorption. Care should be taken when interpreting slopes m of plots of the type log K p = m log p L0 + b based on 24 h means, as these are found sensitive to the time averaging, i.e. tend to be higher than when based on 12 h-mean samples.

  17. Gas purge-microsyringe extraction: a rapid and exhaustive direct microextraction technique of polycyclic aromatic hydrocarbons from plants.

    Science.gov (United States)

    Wang, Juan; Yang, Cui; Li, Huijie; Piao, Xiangfan; Li, Donghao

    2013-12-17

    Gas purge-microsyringe extraction (GP-MSE) is a rapid and exhaustive microextraction technique for volatile and semivolatile compounds. In this study, a theoretical system of GP-MSE was established by directly extracting and analyzing 16 kinds of polycyclic aromatic hydrocarbons (PAHs) from plant samples. On the basis of theoretical consideration, a full factorial experimental design was first used to evaluate the main effects and interactions of the experimental parameters affecting the extraction efficiency. Further experiments were carried out to determine the extraction kinetics and desorption temperature-dependent. The results indicated that three factors, namely desorption temperature (temperature of sample phase) Td, extraction time t, and gas flow rate u, had a significantly positive effect on the extraction efficiency of GP-MSE for PAHs. Extraction processes of PAHs in plant samples followed by first-order kinetics (relative coefficient R(2) of simulation curves were 0.731-1.000, with an average of 0.958 and 4.06% relative standard deviation), and obviously depended on the desorption temperature. Furthermore, the effect of the matrix was determined from the difference in Eapp,d. Finally, satisfactory recoveries of 16 PAHs were obtained using optimal parameters. The study demonstrated that GP-MSE could provide a rapid and exhaustive means of direct extraction of PAHs from plant samples. The extraction kinetics were similar that of the inverse process of the desorption kinetics of the sample phase.

  18. Determination of Hydrocarbon Group-Type of Diesel Fuels by Gas Chromatography with Vacuum Ultraviolet Detection.

    Science.gov (United States)

    Weber, Brandon M; Walsh, Phillip; Harynuk, James J

    2016-06-07

    A GC-vacuum ultraviolet (UV) method to perform group-type separations of diesel range fuels was developed. The method relies on an ionic liquid column to separate diesel samples into saturates, mono-, di-, and polyaromatics by gas chromatography, with selective detection via vacuum UV absorption spectroscopy. Vacuum UV detection was necessary to solve a coelution between saturates and monoaromatics. The method was used to measure group-type composition of 10 oilsands-derived Synfuel light diesel samples, 3 Syncrude light gas oils, and 1 quality control sample. The gas chromatography (GC)-vacuum UV results for the Synfuel samples were similar (absolute % error of 0.8) to historical results from the supercritical fluid chromatography (SFC) analysis. For the light gas oils, discrepancies were noted between SFC results and GC-vacuum UV results; however, these samples are known to be challenging to quantify by SFC-flame ionization detector (FID) due to incomplete resolution between the saturate/monoaromatic and/or monoaromatic/diaromatic group types when applied to samples heavier than diesel (i.e., having a larger fraction of higher molecular weight species). The quality control sample also performed well when comparing both methods (absolute % error of 0.2) and the results agreed within error for saturates, mono- and polyaromatics.

  19. Using Concentrations of Methane and Gasoline Hydrocarbons in Soil Gas to Predict Vapor Intrusion of Benzene

    Science.gov (United States)

    Risk management of petroleum vapor intrusion has been a daunting and challenging task for the Underground Storage Tank Program. Because chlorinated solvents do not degrade in soil gas, techniques that focus on their properties and behavior can produce useful estimates. However, t...

  20. The Separation and Identification of Straight Chain Hydrocarbons: An Experiment Using Gas-Liquid Chromatography.

    Science.gov (United States)

    Benson, G. A.

    1982-01-01

    An experiment using gas-liquid chromatography is discussed, introducing the student to concept of dead volume and its measurement, idea and use of an internal reference compound, and to linear relationship existing between measurements of a separation on two different stationary phases. (Author/SK)

  1. Hydrocarbon gases in Baikal bottom sediments: preliminary results of the Second international Class@Baikal cruise

    Science.gov (United States)

    Vidischeva, Olesya; Akhmanov, Grigorii; Khlystov, Oleg; Giliazetdinova, Dina

    2016-04-01

    In July 2015 the research cruise in the waters of Lake Baikal was carried out onboard RV "G.Yu. Vereshchagin". The expedition was organized by Lomonosov Moscow State University and Limnological Institute of Russian Academy of Sciences. The main purpose of the expedition was to study the modern sedimentation and natural geological processes on the bottom of Lake Baikal. One of the tasks of the cruise was to conduct gas-geochemical survey of bottom sediments. The samples of hydrocarbon gases were collected during the cruise. Subsequent study of the composition and origin of the sampled gas was carried out in the laboratories of Moscow State University. 708 samples from 61 bottom sampling stations were studied. Analyzed samples are from seven different areas located in the southern and central depressions of the lake: (1) "Goloustnoe" seepage area; (2) Bolshoy mud volcano; (3) Elovskiy Area; (4) "Krasny Yar" Seep; (5) "St. Petersburg" Seep; (6) Khuray deep-water depositional system; and (7) Kukuy Griva (Ridge) area. The results of molecular composition analysis indicate that hydrocarbon gases in bottom sediments from almost all sampling stations are represented mostly by pure methane. Ethane was detected only in some places within "Krasny Yar", "Goloustnoe" and "St. Petersburg" seepage areas. The highest concentrations of methane were registered in the sediments from the "Krasny Yar" area - 14 457 μl/l (station TTR-BL15-146G) - and from the "St. Petersburg" area - 13 684 μl/l (station TTR-BL15-125G). The sediments with high concentrations of gases were sampled from active fluid discharge areas, which also can be well distinguished on the seismic profiles. Gas hydrates were obtained in the areas of "Krasny Yar", "Goloustnoe", and "St. Petersburg" seeps and in the area of the Bolshoy mud volcano. Isotopic composition δ13C(CH4) was studied for 100 samples of hydrocarbon gases collected in areas with high methane concentration in bottom sediments. The average value is

  2. Multi-metallic oxides as catalysts for light alcohols and hydrocarbons from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Miguel [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Diaz, L; Galindo, H de J; Dominguez, J. M; Salmon, Manuel [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1999-08-01

    A series of Cu-Co-Cr oxides doped with alkaline metals (M), were prepared by the coprecipitation method with metal nitrates (Cu{sup I}I, CO{sup I}I, CR{sup I}II) and (M{sub 2})CO{sub 3} in aqueous solution. The calcined products were used as catalysts for the Fisher-Tropsch synthesis in a stainless-steel fixed bed microreactor. The material was characterized by x-ray diffraction, and the specific surface area, pore size and nitrogen adsorption-desorption properties were also determined. The alkaline metals favored the methanol synthesis and prevent the dehydration reactions whereas the hydrocarbon formation is independent to these metals. [Spanish] Una serie de oxidos Cu-Co-Cr soportados con metales alcalinos (M), fueron preparados por el metodo con nitratos metalicos (Cu{sup I}I, CO{sup I}I, CR{sup I}II) y (M{sub 2})CO{sub 3} en soluciones acuosas. Los productos calcinados fueron usados como catalizadores para la sintesis de Fisher-tropsch en la superficie fija de un microreactor de acero inoxidable. El material fue caracterizado por difraccion de rayos X y el area de superficie especifica, el tamano de poro y propiedades de absorcion-desorcion de nitrogeno fueron determinadas. Los metales alcalinos favorecieron la sintesis de metanol y previnieron las reacciones de deshidratacion, mientras que la formacion de hidrocarburos es independiente de estos metales.

  3. Hydrocarbon charge of a bacterial gas field by prolonged methanogenesis: an example from the East Java Sea, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Noble, R.A.; Henk, F.H. [Atlantic Richfield Indonesia Inc., Jakarta (Indonesia)

    1998-12-31

    The Terang-Sirasun Field in the East Java Sea of Indonesia contains 1.0 trillion cubic feet (TCF) of dry gas reserves, which are made up of over 99.5% methane with {delta}{sup 13}C of -65 per thousandth and {delta}D of -185%. The methane was formed exclusively by methanogenic bacteria via the CO{sub 2} reduction pathway. The primary source sediments for the methane were identified based on bulk geochemical and absolute biomarker concentrations. Specifically, the C{sub 25} acyclic isoprenoid 2,6,10,15,19-pentamethyleicosane (PME), and related isoprenyl glyceryl ethers, which are well known markers for methanogenic archaebacteria, were used as indicators for sediment layers thought to have had the most abundant methanogen activity. Burial history analysis and precise biostratigraphic age control provided the framework for assessing the timing of hydrocarbon fill. Our findings show that methanogenic activity was highest in marine shelfal claystones (mid-outer neritic) ranging in age from 8 Ma (Late Miocene) to present. The gas is reservoired in limestones and sands of the Paciran Member, which are dated from 6.5 to 1.3 Ma (Late Miocene-Pliocene). The top seal for the present accumulation was deposited less than 0.5 Ma ago (Quarternary), although there is strong geological evidence that older seals existed. The information obtained from this field study provides evidence that large accumulations of bacterial methane do not necessarily require early entrapment of methane from freshly deposited marine sediments. Traps may be filled with bacterial gas long after the deposition of source beds, provided that the required conditions for active methanogenesis are maintained throughout this period. (author)

  4. Characteristics of polycyclic aromatic hydrocarbons and their gas/particle partitioning from fugitive emissions in coke plants

    Science.gov (United States)

    Mu, Ling; Peng, Lin; Liu, Xiaofeng; Song, Chongfang; Bai, Huiling; Zhang, Jianqiang; Hu, Dongmei; He, Qiusheng; Li, Fan

    2014-02-01

    Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas-particle partitioning of PAHs. In this study, emission characteristics and gas-particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m-3, which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m-3). Low molecular weight PAHs with 2-3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaPeq) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaPeq concentrations varied from 0.19 to 10.86 μg m-3 with an average of 3.14 μg m-3, and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas-particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu.

  5. Petroleum biodegradation studied in sediment-flow-through systems simulating natural oil seepage in marine sediments

    Science.gov (United States)

    Mishra, Sonakshi; Wefers, Peggy; Steeb, Philip; Schmidt, Mark; Treude, Tina

    2014-05-01

    The natural biodegradation of hydrocarbons depends on several environmental factors like nutrients, salinity, temperature, pressure, redox-conditions and composition of crude oil. Petroleum migrating from depth into marine surface sediments at natural seep sites could be subjected to a sequence of different kind of microbial processes which is controlled by a strong redox gradient within a thin sediment segment. Most studies on microbial degradation of petroleum have focused either only on selected hydrocarbon fractions or on cultured microbes. This study, however, attempts to investigate the natural microbial response of marine sediments to crude oil seepage with detailed analysis of sediment and porewater geochemistry, hydrocarbon degradation products, microbial activity, and microbial genetics. A sediment-oil-flow-through-system was established where crude oil migrated through the bottom of (approximately 30 cm long) intact marine sediment cores simulating a natural seepage scenario. Electron acceptor-rich oxic seawater was provided at the top of the core and anoxic conditions were established at the bottom of the cores. The intact sediment cores had been sampled from the Caspian Sea (near Baku) and the North Alex Mud Volcano in the Mediterranean Sea. The Caspian Sea and the North Alex Mud Volcano are both sites with active transport of hydrocarbons from depth by mud volcano activity. The geochemical changes in the sediment cores during oil seepage were monitored by using microelectrodes and porewater analyses. The geochemical analysis was later followed by hydrocarbon and molecular analyses at the end of the experiment by slicing the cores. First results based on the biogeochemistry of the sediment cores and hydrocarbon analyses are presented here. Porewater profiles of hydrogen sulfide and sulfate during the experimental runs gave first indications of microbial response and sulfate reduction due to the addition of crude oil. The core from North Alex Mud

  6. Natural Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin: Source Identification and Inventory

    Science.gov (United States)

    Lorenson, T.D.; Hostettler, Frances D.; Rosenbauer, Robert J.; Peters, Kenneth E.; Dougherty, Jennifer A.; Kvenvolden, Keith A.; Gutmacher, Christina E.; Wong, Florence L.; Normark, William R.

    2009-01-01

    Oil spillage from natural sources is very common in the waters of southern California. Active oil extraction and shipping is occurring concurrently within the region and it is of great interest to resource managers to be able to distinguish between natural seepage and anthropogenic oil spillage. The major goal of this study was to establish the geologic setting, sources, and ultimate dispersal of natural oil seeps in the offshore southern Santa Maria Basin and Santa Barbara Basins. Our surveys focused on likely areas of hydrocarbon seepage that are known to occur between Point Arguello and Ventura, California. Our approach was to 1) document the locations and geochemically fingerprint natural seep oils or tar; 2) geochemically fingerprint coastal tar residues and potential tar sources in this region, both onshore and offshore; 3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; 4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; and 5) interpret the petroleum system history for the natural seeps. To document the location of sub-sea oil seeps, we first looked into previous studies within and near our survey area. We measured the concentration of methane gas in the water column in areas of reported seepage and found numerous gas plumes and measured high concentrations of methane in the water column. The result of this work showed that the seeps were widely distributed between Point Conception east to the vicinity of Coal Oil Point, and that they by in large occur within the 3-mile limit of California State waters. Subsequent cruises used sidescan and high resolution seismic to map the seafloor, from just south of Point Arguello, east to near Gaviota, California. The results of the methane survey guided the exploration of the area west of Point Conception east to Gaviota using a combination of seismic instruments. The

  7. Estimation and Prediction of Gas Chromatography Retention Indices of Hydrocarbons in Straight-run Gasoline by Using Artificial Neural Network and Structural Coding Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The molecular structures of hydrocarbons in straight-run gasoline were numerically coded. The nonlinear quantitative relationship(QSRR) between gas chromatography(GC) retention indices of the hydrocarbons and their molecular structures were established by using an error back-propagation(BP) algorithm. The GC retention indices of 150 hydrocarbons were then predicted by removing 15 compounds(as a test set) and using the 135 remained molecules as a calibration set. Through this procedure, all the compounds in the whole data set were then predicted in groups of 15 compounds. The results obtained by BP with the correlation coefficient and the standard deviation 0.993 4 and 16.54, are satisfied.

  8. Estimating emissions of toxic hydrocarbons from natural gas production sites in the Barnett Shale region

    Science.gov (United States)

    Marrero, J. E.; Townsend-Small, A.; Lyon, D. R.; Tsai, T.; Meinardi, S.; Blake, D. R.

    2015-12-01

    Throughout the past decade, shale gas operations have moved closer to urban centers and densely populated areas, contributing to growing public concerns regarding exposure to hazardous air pollutants (HAPs). These HAPs include gases like hexane, 1,3-butadiene and BTEX compounds, which can cause minor health effects from short-term exposure or possibly cancer due to prolonged exposure. During the Barnett Shale Coordinated Campaign in October, 2013, ground-based whole air samples revealed enhancements in several of these toxic volatile organic compounds (VOCs) downwind of natural gas well pads and compressor stations. Two methods were used to estimate the emission rate of several HAPs in the Barnett Shale. The first method utilized CH4 flux measurements derived from the Picarro Mobile Flux Plane (MFP) and taken concurrently with whole air samples, while the second used a CH4 emissions inventory developed for the Barnett Shale region. From these two approaches, the regional emission estimate for benzene (C6H6) ranged from 48 ± 16 to 84 ± 26 kg C6H6 hr-1. A significant regional source of atmospheric benzene is evident, despite measurement uncertainty and limited number of samples. The extent to which these emission rates equate to a larger public health risk is unclear, but is of particular interest as natural gas productions continues to expand.

  9. Infiltration and Seepage Through Fractured Welded Tuff

    Energy Technology Data Exchange (ETDEWEB)

    T.A. Ghezzehei; P.F. Dobson; J.A. Rodriguez; P.J. Cook

    2006-06-20

    The Nopal I mine in Pena Blanca, Chihuahua, Mexico, contains a uranium ore deposit within fractured tuff. Previous mining activities exposed a level ground surface 8 m above an excavated mining adit. In this paper, we report results of ongoing research to understand and model percolation through the fractured tuff and seepage into a mined adit both of which are important processes for the performance of the proposed nuclear waste repository at Yucca Mountain. Travel of water plumes was modeled using one-dimensional numerical and analytical approaches. Most of the hydrologic properly estimates were calculated from mean fracture apertures and fracture density. Based on the modeling results, we presented constraints for the arrival time and temporal pattern of seepage at the adit.

  10. Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Aerosol Dynamics Inc; Aerodyne Research, Inc.,; Tofwerk AG, Thun; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Doug R.; Goldstein, Allen H.

    2011-09-13

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  11. Seepage characteristics of collapse column fillings

    Institute of Scientific and Technical Information of China (English)

    Zhang Boyang; Bai Haibo; Zhang Kai

    2016-01-01

    With concealment and hysteresis, water-inrush from Karst collapse column has become an important security hazard of lower group coal mining in North China. Based on the MTS815.02 seepage test system, we analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings. The results show that:(1) The permeability of collapse column fillings is of the order of 10?16–10?15 magni-tude and decreases with an increase in consolidation pressure and decrease in initial moisture content. (2) The essence of filling seepage law change is the change in porosity, and a power function relationship exists between the permeability ratio and porosity ratio. (3) With increasing confining pressure, the per-meability of fillings decreases. However, under low confining pressure (1.2–4 MPa), the change of confin-ing pressure has no obvious influence on the permeability.

  12. Three-dimensional numerical simulations of methane gas migration from decommissioned hydrocarbon production wells into shallow aquifers

    Science.gov (United States)

    Roy, N.; Molson, J.; Lemieux, J.-M.; Van Stempvoort, D.; Nowamooz, A.

    2016-07-01

    Three-dimensional numerical simulations are used to provide insight into the behavior of methane as it migrates from a leaky decommissioned hydrocarbon well into a shallow aquifer. The conceptual model includes gas-phase migration from a leaky well, dissolution into groundwater, advective-dispersive transport and biodegradation of the dissolved methane plume. Gas-phase migration is simulated using the DuMux multiphase simulator, while transport and fate of the dissolved phase is simulated using the BIONAPL/3D reactive transport model. Methane behavior is simulated for two conceptual models: first in a shallow confined aquifer containing a decommissioned leaky well based on a monitored field site near Lindbergh, Alberta, Canada, and secondly on a representative unconfined aquifer based loosely on the Borden, Ontario, field site. The simulations show that the Lindbergh site confined aquifer data are generally consistent with a 2 year methane leak of 2-20 m3/d, assuming anaerobic (sulfate-reducing) methane oxidation and with maximum oxidation rates of 1 × 10-5 to 1 × 10-3 kg/m3/d. Under the highest oxidation rate, dissolved methane decreased from solubility (110 mg/L) to the threshold concentration of 10 mg/L within 5 years. In the unconfined case with the same leakage rate, including both aerobic and anaerobic methane oxidation, the methane plume was less extensive compared to the confined aquifer scenarios. Unconfined aquifers may therefore be less vulnerable to impacts from methane leaks along decommissioned wells. At other potential leakage sites, site-specific data on the natural background geochemistry would be necessary to make reliable predictions on the fate of methane in groundwater.

  13. Evaluation of polycyclic aromatic hydrocarbons in asphalt binder using matrix solid-phase dispersion and gas chromatography.

    Science.gov (United States)

    Fernandes, Paulo R N; Soares, Sandra de A; Nascimento, Ronaldo F; Soares, Jorge B; Cavalcante, Rivelino M

    2009-10-01

    A method developed for the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) in the asphalt binder using a matrix solid-phase dispersion (MSPD) and gas chromatography is presented. The MSPD method was proposed as a rapid and easy approach to determining PAHs present in the maltenic phase of asphalt binder extracted through a mechanical shaking and sonication of the material. The recovery rates ranged from 62.77-89.92% (shaking) and from 56.54-93.6% (sonication) with relative standard deviations lower than 8.8%. The study shows that the recovery rates using shaking and sonication extractions are not significantly different at the p asphalt binder from Brazil. The main PAHs found were BbF, BaP, Per, IncdP, DahA, and BghiP, with average concentrations of 10.2-20.7 mg/kg, but the PAHs Ace and Acy were not detected. However, Nap, Fl, Phen, Ant, Flr, Pyr, Chry, BaA, and BkF were present in average concentrations amounting to less than 10 mg/kg. The results showed that the MSPD method is potentially a valuable tool for the determination of PAHs in the asphalt binder.

  14. Role of weathered coal tar pitch in the partitioning of polycyclic aromatic hydrocarbons in manufactured gas plant site sediments.

    Science.gov (United States)

    Khalil, Muhammad F; Ghosh, Upal; Kreitinger, Joseph P

    2006-09-15

    Polycyclic aromatic hydrocarbons (PAHs) in manufactured gas plant (MGP) site sediments are often associated with carbonaceous particles that reduce contaminant bioavailability. Although black carbon inclusive partitioning models have been proposed to describe elevated PAH partitioning behavior, questions remain on the true loading and association of PAHs in different particle types in industrially impacted sediments. In the studied MGP sediments, the light density organic particles (coal, coke, wood, and coal tar pitch) comprised 10-20% of the total mass and 70-95% of the PAHs. The remainder of the PAHs in sediment was associated with the heavy density particles (i.e., sand, silt, and clays). Among the different particle types, coal tar pitch (quantified by a quinoline extraction method) contributed the most to the bulk sediment PAH concentration. Aqueous partition coefficients for PAHs measured using a weathered pitch sample from the field were generally an order of magnitude higher than reported for natural organic matter partitioning, and match well with theoretical predictions based on a coal tar-water partitioning model. A pitch-partitioning inclusive model is proposed that gives better estimates of the measured site-specific PAH aqueous equilibrium values than standard estimation based on natural organic matter partitioning only. Thus, for MGP impacted sediments containing weathered pitch particles, the partitioning behavior may be dominated by the sorption characteristics of pitch and not by natural organic matter or black carbon.

  15. Metal catalysts supported on activated carbon fibers for removal of polycyclic aromatic hydrocarbons from incineration flue gas.

    Science.gov (United States)

    Lin, Chiou-Liang; Cheng, Yu-Hsiang; Liu, Zhen-Shu; Chen, Jian-Yuan

    2011-12-15

    The aim of this research was to use metal catalysts supported on activated carbon fibers (ACFs) to remove 16 species of polycyclic aromatic hydrocarbons (PAHs) from incineration flue gas. We tested three different metal loadings (0.11 wt%, 0.29 wt%, and 0.34 wt%) and metals (Pt, Pd, and Cu), and two different pretreatment solutions (HNO(3) and NaOH). The results demonstrated that the ACF-supported metal catalysts removed the PAHs through adsorption and catalysis. Among the three metals, Pt was most easily adsorbed on the ACFs and was the most active in oxidation of PAHs. The mesopore volumes and density of new functional groups increased significantly after the ACFs were pretreated with either solutions, and this increased the measured metal loading in HNO(3)-0.48% Pd/ACFs and NaOH-0.52% Pd/ACFs. These data confirm that improved PAH removal can be achieved with HNO(3)-0.48% Pd/ACFs and NaOH-0.52% Pd/ACFs.

  16. Solution of AntiSeepage for Mengxi River Based on Numerical Simulation of Unsaturated Seepage

    Directory of Open Access Journals (Sweden)

    Youjun Ji

    2014-01-01

    Full Text Available Lessening the leakage of surface water can reduce the waste of water resources and ground water pollution. To solve the problem that Mengxi River could not store water enduringly, geology investigation, theoretical analysis, experiment research, and numerical simulation analysis were carried out. Firstly, the seepage mathematical model was established based on unsaturated seepage theory; secondly, the experimental equipment for testing hydraulic conductivity of unsaturated soil was developed to obtain the curve of two-phase flow. The numerical simulation of leakage in natural conditions proves the previous inference and leakage mechanism of river. At last, the seepage control capacities of different impervious materials were compared by numerical simulations. According to the engineering actuality, the impervious material was selected. The impervious measure in this paper has been proved to be effectible by hydrogeological research today.

  17. Prospects for applications of electron beams in processing of gas and oil hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Ponomarev, A. V., E-mail: ponomarev@ipc.rssi.ru [Russian Academy of Sciences, Frumkin Institute of Physical Chemistry and Electrochemistry (Russian Federation); Pershukov, V. A. [ROSATOM National Nuclear Corporation (Russian Federation); Smirnov, V. P. [CJSC “Nauka i Innovatsii” (Russian Federation)

    2015-12-15

    Waste-free processing of oil and oil gases can be based on electron-beam technologies. Their major advantage is an opportunity of controlled manufacturing of a wide range of products with a higher utility value at moderate temperatures and pressures. The work considers certain key aspects of electron beam technologies applied for the chain cracking of heavy crude oil, for the synthesis of premium gasoline from oil gases, and also for the hydrogenation, alkylation, and isomerization of unsaturated oil products. Electronbeam processing of oil can be embodied via compact mobile modules which are applicable for direct usage at distant oil and gas fields. More cost-effective and reliable electron accelerators should be developed to realize the potential of electron-beam technologies.

  18. Hydrocarbon emissions from lean-burn natural gas engines. Kinetic modelling and visualization

    Energy Technology Data Exchange (ETDEWEB)

    Broe Bendtsen, A.

    1999-07-01

    Motivated by emissions of unburned fuel from natural gas engines, a detailed chemical kinetic model describing NO{sub x} sensitized oxidation of methane was developed. New methods for visualization of such complex models have been developed, based on chemometrics and explorative data analysis. They may find application in combustion chemistry and in atmospheric chemistry, where detailed kinetic models are widely used. The motivation of the project was the discovery of significant emissions of unburned fuel from natural gas engines. The thesis contains a brief summary of emission levels and the sources of these emissions. Results from experiments by the Danish Gas Technology Centre on a pilot scale engine showed that oxidation of methane may occur in an extended exhaust manifold. Based on these results experiments were initiated to obtain detailed knowledge of the governing oxidation chemistry in the exhaust manifold. A series of laboratory experiments showed that at a residence time of 200 ms the threshold temperature for oxidation of methane was lowered by 200 {kappa} from 1100 {kappa} to 900 {kappa} in the presence of NO or NO{sub 2}. Experiments with a residence time of 140 ms showed that the sensitizing effect of NO was related to a longer lag time, compared to effect of NO{sub 2}. The major product of oxidation from 900 {kappa} to 1100 {kappa} was CO. Published detailed chemical kinetic models were not able to describe these phenomena. It was attempted to modify existing kinetic models to describe this sensitization by estimation of reaction rates. A literature survey of various method for estimation of reaction rates is given, and one methods for estimation of reaction rates using Partial Least Squares regression is demonstrated, but only with moderate success. To obtain a better kinetic model, a conventional approach to the refinement of the kinetic model was assisted by visualization methods and explorative data analysis. Through this approach an existing

  19. Hydrocarbon fuels from gas phase decarboxylation of hydrolyzed free fatty acid

    KAUST Repository

    Wang, Weicheng

    2012-01-01

    Gas phase decarboxylation of hydrolyzed free fatty acid (FFA) from canola oil has beeninvestigated in two fix-bed reactors by changing reaction parameters such as temperatures,FFA feed rates, and H 2-to-FFA molar ratios. FFA, which contains mostly C 18 aswell as a few C 16, C 20, C 22, and C 24 FFA, was fed into the boiling zone, evaporated, carriedby hydrogen flow at the rate of 0.5-20 ml/min, and reacted with the 5% Pd/C catalystin the reactor. Reactions were conducted atmospherically at 380-450 °C and the products,qualified and quantified through gas chromatography-flame ionization detector(GC-FID), showed mostly n-heptadecane and a few portion of n-C 15, n-C 19, n-C 21, n-C 23 as well as some cracking species. Results showed that FFA conversion increased withincreasing reaction temperatures but decreased with increasing FFA feed rates and H 2-to-FFA molar ratios. The reaction rates were found to decrease with higher temperatureand increase with higher H 2 flow rates. Highly selective heptadecane was achieved byapplying higher temperatures and higher H 2-to-FFA molar ratios. From the results, ascatalyst loading and FFA feed rate were fixed, an optimal reaction temperature of 415 °C as well as H 2-to-FFA molar ratio of 4.16 were presented. These results provided goodbasis for studying the kinetics of decarboxylation process. © 2012 American Society of Mechanical Engineers.

  20. Raman characteristics of hydrocarbon and hydrocarbon inclusions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Nai; TIAN ZuoJi; LENG YingYing; WANG HuiTong; SONG FuQing; MENG JianHua

    2007-01-01

    The Raman spectrograms of hydrocarbon standard samples show that: (1) the Raman spectrogram of normal paraffin has very strong peaks of methyl and methylene (from 2700 cm-1 to 2970 cm-1); (2)branch methyl has the particular peak of 748 cm-1±; (3) six cyclic has the particular peak of 804 cm-1±; (4)phenyl has two particular peaks of 988 cm-1± and 3058 cm-1± and the 988 cm-1± peak is stronger than the 3058 cm-1± peak; and (5) hexene has three alkenyl spectrum peaks of 1294 cm-1±, 1635 cm-1± and 2996 cm-1±, with the 1635 cm-1± peak being the strongest, showing that the number of carbon in hydrocarbon does not affect its Raman spectrogram, and the hydrocarbon molecular structure and base groups affect its Raman spectrogram, the same hydrocarbons (such as normal paraffin) have the same Raman spectrogram; the types (such as CH4, C2H6, C3H8) and the content of hydrocarbon in oil inclusions are not estimated by their characteristic Raman peaks. According to the Raman spectrograms of hydrocarbon compositions, the Raman spectrogram of hydrocarbon inclusion can be divided into five types: saturated hydrocarbon Raman spectrogram, fluoresce Raman spectrogram, saturated hydrocarbon bitumen Raman spectrogram, bitumen Raman spectrogram, and ethane Raman spectrogram.And according to the characteristics of Raman spectrogram, hydrocarbon inclusions can be divided into five types: saturated hydrocarbon inclusion, less saturated hydrocarbon (oil or gas) inclusion,saturated hydrocarbon bitumen inclusion, bitumen inclusion, and methane water inclusion.

  1. Raman characteristics of hydrocarbon and hydrocarbon inclusions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Raman spectrograms of hydrocarbon standard samples show that: (1) the Raman spectrogram of normal paraffin has very strong peaks of methyl and methylene (from 2700 cm-1 to 2970 cm-1); (2) branch methyl has the particular peak of 748 cm-1±; (3) six cyclic has the particular peak of 804 cm-1±; (4) phenyl has two particular peaks of 988 cm-1± and 3058 cm-1± and the 988 cm-1± peak is stronger than the 3058 cm-1± peak; and (5) hexene has three alkenyl spectrum peaks of 1294 cm-1±, 1635 cm-1± and 2996 cm-1±, with the 1635 cm-1± peak being the strongest, showing that the number of carbon in hy-drocarbon does not affect its Raman spectrogram, and the hydrocarbon molecular structure and base groups affect its Raman spectrogram, the same hydrocarbons (such as normal paraffin) have the same Raman spectrogram; the types (such as CH4, C2H6, C3H8) and the content of hydrocarbon in oil inclu-sions are not estimated by their characteristic Raman peaks. According to the Raman spectrograms of hydrocarbon compositions, the Raman spectrogram of hydrocarbon inclusion can be divided into five types: saturated hydrocarbon Raman spectrogram, fluoresce Raman spectrogram, saturated hydro-carbon bitumen Raman spectrogram, bitumen Raman spectrogram, and ethane Raman spectrogram. And according to the characteristics of Raman spectrogram, hydrocarbon inclusions can be divided into five types: saturated hydrocarbon inclusion, less saturated hydrocarbon (oil or gas) inclusion, saturated hydrocarbon bitumen inclusion, bitumen inclusion, and methane water inclusion.

  2. Polycyclic aromatic hydrocarbon in fine particulate matter emitted from burning kerosene, liquid petroleum gas, and wood fuels in household cookstoves

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes all data in figures in the manuscript and supporting information for the publication entitled "Particulate polycyclic aromatic hydrocarbon...

  3. Hydrocarbon pneumonia

    Science.gov (United States)

    Pneumonia - hydrocarbon ... Coughing Fever Shortness of breath Smell of a hydrocarbon product on the breath Stupor (decreased level of ... Most children who drink or inhale hydrocarbon products and develop ... hydrocarbons may lead to rapid respiratory failure and death.

  4. Quantification of methane fluxes from hydrocarbon seeps to the ocean and atmosphere: Development of an in situ and online gas flux measuring system

    Science.gov (United States)

    Di, Pengfei; Chen, Qinghua; Chen, Duofu

    2017-06-01

    Natural hydrocarbon seeps in the marine environment are important contributors to greenhouse gases in the atmosphere. Such gases include methane, which plays a significant role in global carbon cycling and climate change. To accurately quantify the methane flux from hydrocarbon seeps on the seafloor, a specialized in situ and online gas flux measuring (GFM) device was designed to obtain high-resolution time course gas fluxes using the process of equal volume exchange. The device consists of a 1.0-m diameter, 0.9-m tall, inverted conical tent and a GFM instrument that contains a solenoid valve, level transducer, and gas collection chamber. Rising gas bubbles from seeps were measured by laboratory-calibrated GFM instruments attached to the top of the tent. According to the experimental data, the optimal anti-shake time interval was 5 s. The measurement range of the device was 0-15 L min-1, and the relative error was ± 1.0%. The device was initially deployed at an active seep site in the Lingtou Promontory seep field in South China Sea. The amount of gas released from a single gas vent was 30.5 m3 during the measurement period, and the gas flow rate ranged from 22 to 72 L h-1, depending on tidal period, and was strongly negatively correlated with water depth. The measurement results strongly suggest that oceanic tides and swells had a significant forcing effect on gas flux. Low flow rates were associated with high tides and vice versa. The changes in gas volume escaping from the seafloor seeps could be attributed to the hydrostatic pressure induced by water depth. Our findings suggest that in the marine environment, especially in the shallow shelf area, sea level variation may play an important role in controlling methane release into the ocean. Such releases probably also affect atmospheric methane levels.

  5. 气相光催化氧化降解卤代烃的研究%Gas-Phase Photocatalytic Oxidation of Halogenated Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    李功虎; 安纬珠

    2000-01-01

      本文介绍了气相光催化作用的基本原理,从光催化剂的改性技术、反应动力学和反应机理三个方面综述了近年来气相光催化氧化降解卤代烃的研究。%  This paper introduced the photocatalyzing principle of semiconductor in gas phase,and summarized the recent studies on the gas-phase photocatalytic oxidation of halogenated hydrocarbons,including modification of semiconductor,reaction kinetics and the degradation mechanism of TCE.

  6. A new Arctic seepage site? Preliminary evidence from benthic community

    Science.gov (United States)

    Caridi, Francesca; Sabbatini, Anna; Morigi, Caterina; Giulia Lucchi, Renata

    2017-04-01

    The Kveithola Trough is an abrupt and narrow sedimentary system located in the NW Barents Sea. The hydrographic, bio-geochemical conditions and the possible existence of gas seepage activity of the area have been investigated during the Eurofleets 2- BURSTER cruise, conducted on board the German icebreaker RV Polarstern. The aim of our work is to characterize the benthic biota and more specifically the macrofaunal community structure coupled to the study of benthic foraminiferal meiofauna. Preliminary qualitative results revealed that in the inner Kveithola Trough, the macrofaunal community is composed by abundant black worm tubes (Chaetopteridae worms and Siboglinidae-like taxa) with presence of Thyasiridae bivalve species. The occurrence of these macrofaunal taxa is usually associated to oxygen-reduced environments, hydrothermal vents and cold seeps. The living benthic foraminiferal assemblage in the same stations is characterized by the presence of typically oxygen-depleted environmental taxa including the calcareous species Nonionellina labradorica and Globobulimina spp.. Conversely, in the outer Kveithola trough, both benthic macrofauna and foraminiferal meiofauna assemblages are characterized by less opportunistic taxa with a higher biodiversity suggesting very distinct oceanographic sea bottom conditions. The organic matter richness plays a large role in the Kveithola Trough environmental setting and may bring anoxic conditions that could affect the biota of the area. In fact, the benthic community structure of this area inhabits suboxic, anoxic and organic-enriched sediments and disturbed environments, forming assemblages with low diversity and high abundances of a few tolerant and/or specialized species. This preliminary finding could be consistent with other studies examining benthic community structure around Svalbard and in particular cold seep and vents habitats where faunal characteristics are patchy, suggesting small-scale heterogeneity in the

  7. Seepage and stress analysis of anti-seepage structures constructed with different concrete materials in an RCC gravity dam

    Directory of Open Access Journals (Sweden)

    Ming-chao Li

    2015-10-01

    Full Text Available This study used the finite element method (FEM to analyze the stress field and seepage field of a roller-compacted concrete (RCC dam, with an upstream impervious layer constructed with different types of concrete materials, including three-graded RCC, two-graded RCC, conventional vibrated concrete (CVC, and grout-enriched vibrated RCC (GEVR, corresponding to the design schemes S1 through S4. It also evaluated the anti-seepage performance of the imperious layer in the four design schemes under the normal water level and flood-check level. Stress field analysis of a retaining section and discharge section shows that the maximum tensile stress occurs near the dam heel, the maximum compressive stress occurs near the dam toe, and the stress distributions in the four schemes can satisfy the stress control criteria. Seepage field analysis shows that the uplift pressure heads in schemes S3 and S4 descend rapidly in the anti-seepage region, and that the calculated results of daily seepage flow under the steady seepage condition in these two schemes are about 30% to 50% lower than those in the other two schemes, demonstrating that CVC and GEVR show better anti-seepage performance. The results provide essential parameters such as the uplift pressure head and seepage flow for physical model tests and anti-seepage structure selection in RCC dams.

  8. Greatly reduced bioavailability and toxicity of polycyclic aromatic hydrocarbons to Hyalella azteca in sediments from manufactured-gas plant sites.

    Science.gov (United States)

    Kreitinger, Joseph P; Neuhauser, Edward F; Doherty, Francis G; Hawthorne, Steven B

    2007-06-01

    The toxicity of polycyclic aromatic hydrocarbons (PAHs) to Hyalella azteca, was measured in 34 sediment samples collected from four manufactured-gas plant (MGP) sites ranging in total PAH16 (sum of 16 U.S. Environmental Protection Agency priority pollutant PAHs) concentrations from 4 to 5700 mg/kg, total organic carbon content from 0.6 to 11%, and soot carbon from 0.2 to 5.1%. The survival and growth of H. azteca in 28-d bioassays were unrelated to total PAH concentration, with 100% survival in one sediment having 1,730 mg/kg total PAH16, whereas no survival was observed in sediment samples with concentrations as low as 54 mg/kg total PAH16. Twenty-five of the 34 sediment samples exceeded the probable effects concentration screening value of 22.8 mg/kg total PAH13 (sum of 13 PAHs) and equilibrium partitioning sediment benchmarks for PAH mixtures (on the basis of the measurement of 18 parent PAHs and 16 groups of alkylated PAHs, [PAH34]); yet, 19 (76%) of the 25 samples predicted to be toxic were not toxic to H. azteca. However, the toxicity of PAHs to H. azteca was accurately predicted when either the rapidly released concentrations as determined by mild supercritical fluid extraction (SFE) or the pore-water concentrations were used to establish the bioavailability of PAHs. These results demonstrate that the PAHs present in many sediments collected from MGP sites have low bioavailability and that both the measurement of the rapidly released PAH concentrations with mild SFE and the dissolved pore-water concentrations of PAHs are useful tools for estimating chronic toxicity to H. azteca.

  9. Accelerated solvent extraction method for the quantification of polycyclic aromatic hydrocarbons in cocoa beans by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Belo, Renata França Cassimiro; Figueiredo, Júlia Pereira; Nunes, Carolina Mariana; Pissinatti, Rafael; Souza, Scheilla Vitorino Carvalho de; Junqueira, Roberto Gonçalves

    2017-05-15

    An accelerated solvent extraction (ASE) procedure for use with gas chromatography-mass spectrometry (GC-MS) was optimized for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in cocoa beans. Plackett-Burman and rotatable central composite design (RCCD) indicated that three variables affected the recoveries of PAHs during the extraction and purification steps: agitation time in the second liquid-liquid partition, weight of silica gel in the column, and volume of hexane for PAH elution from the column. After obtaining the optimal conditions, a single laboratory method validation was performed. Linearity was demonstrated for benzo[a]pyrene in the concentration range from 0.5 to 8.0mgkg(-1) of sample, corresponding to 1.25-20.0μgkg(-1) of cocoa on a fat basis. For the other analytes, linearity was observed from 0.75 to 8.0μgkg(-1) of sample (1.88-20.0μgkg(-1) of cocoa on a fat basis). Significant matrix effects were found for chrysene and benzo[b]fluoranthene. The precision of the method was verified with relative standard deviations (RSDs) ranging from 2.57 to 14.13% and from 4.36 to 19.77% under repeatability and intermediate precision conditions, respectively. The average recoveries of the eight PAHs ranged from 74.99 to 109.73%. These parameters, limits and measurement uncertainties met the performance criteria established by European Union regulations, except for the theoretical limit of detection for chrysene. The method was applied to the analysis of samples of Brazilian cocoa beans, and only one sample was found to have a PAH content above the maximum limit defined by the European Union legislation. This optimized and validated method is intended to be used as part of the official Brazilian monitoring programs investigating contaminants and residues in food. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Microbial Community Response to Simulated Petroleum Seepage in Caspian Sea Sediments

    Directory of Open Access Journals (Sweden)

    Katrin Knittel

    2017-04-01

    Full Text Available Anaerobic microbial hydrocarbon degradation is a major biogeochemical process at marine seeps. Here we studied the response of the microbial community to petroleum seepage simulated for 190 days in a sediment core from the Caspian Sea using a sediment-oil-flow-through (SOFT system. Untreated (without simulated petroleum seepage and SOFT sediment microbial communities shared 43% bacterial genus-level 16S rRNA-based operational taxonomic units (OTU0.945 but shared only 23% archaeal OTU0.945. The community differed significantly between sediment layers. The detection of fourfold higher deltaproteobacterial cell numbers in SOFT than in untreated sediment at depths characterized by highest sulfate reduction rates and strongest decrease of gaseous and mid-chain alkane concentrations indicated a specific response of hydrocarbon-degrading Deltaproteobacteria. Based on an increase in specific CARD-FISH cell numbers, we suggest the following groups of sulfate-reducing bacteria to be likely responsible for the observed decrease in aliphatic and aromatic hydrocarbon concentration in SOFT sediments: clade SCA1 for propane and butane degradation, clade LCA2 for mid- to long-chain alkane degradation, clade Cyhx for cycloalkanes, pentane and hexane degradation, and relatives of Desulfobacula for toluene degradation. Highest numbers of archaea of the genus Methanosarcina were found in the methanogenic zone of the SOFT core where we detected preferential degradation of long-chain hydrocarbons. Sequencing of masD, a marker gene for alkane degradation encoding (1-methylalkylsuccinate synthase, revealed a low diversity in SOFT sediment with two abundant species-level MasD OTU0.96.

  11. Spatial association analysis between hydrocarbon fields and sedimentary residual magnetic anomalies using Weights of Evidence: An example from the Triassic Province of Algeria

    Science.gov (United States)

    Allek, Karim; Boubaya, Djamel; Bouguern, Abderrahmane; Hamoudi, Mohamed

    2016-12-01

    The presence of near-surface magnetic anomalies over oil and gas accumulations and their contribution to exploration remain somewhat controversial despite encouraging results and an improved understanding of genetic links between hydrocarbon seepage-induced alterations and near-surface magnetic minerals. This controversy is likely to remain since the cause of shallow-sourced sedimentary magnetic anomalies may well be microseepage related, but could also result from other sources such as cultural features and detrital magnetite. The definite way of discriminating between them remains a challenge. In this paper we examine means to deal with this particular purpose using a Bayesian technique known as 'Weights-of-Evidence'. The technique is implemented in GIS to explore spatial associations between known hydrocarbon fields within the central Triassic province of Algeria and sedimentary residual magnetic anomalies. We use the results to show possible application of the method to the recognition of some characteristics (amplitude and width) of anomalies assumed to be induced by hydrocarbon microseepages. Our results reveal strong spatial association with certain typical class of anomalies, confirming therefore hypothesis that hydrocarbon microseepages may result in detectable magnetic anomalies. It is possible to use the anomalies occurring outside the known gas and oil fields to make informed decisions in the selection of new targets for more detailed hydrocarbon exploration.

  12. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    Louw, de P.G.B.; Eeman, S.; Siemon, B.; `Voortman, B.R.; Gunnink, J.; Baaren, E.S.; Oude Essink, G.H.P.

    2011-01-01

    In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and

  13. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    De Louw, Perry G.B.; Eeman, Sara; Siemon, Bernhard; Voortman, Bernard R.; Gunnink, Jan; Van Baaren, Esther S.; Oude Essink, Gualbert

    2011-01-01

    In deltaic areas with saline seepage, fresh water availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence an

  14. Assessing fuel spill risks in polar waters: Temporal dynamics and behaviour of hydrocarbons from Antarctic diesel, marine gas oil and residual fuel oil.

    Science.gov (United States)

    Brown, Kathryn E; King, Catherine K; Kotzakoulakis, Konstantinos; George, Simon C; Harrison, Peter L

    2016-09-15

    As part of risk assessment of fuel oil spills in Antarctic and subantarctic waters, this study describes partitioning of hydrocarbons from three fuels (Special Antarctic Blend diesel, SAB; marine gas oil, MGO; and intermediate grade fuel oil, IFO 180) into seawater at 0 and 5°C and subsequent depletion over 7days. Initial total hydrocarbon content (THC) of water accommodated fraction (WAF) in seawater was highest for SAB. Rates of THC loss and proportions in equivalent carbon number fractions differed between fuels and over time. THC was most persistent in IFO 180 WAFs and most rapidly depleted in MGO WAF, with depletion for SAB WAF strongly affected by temperature. Concentration and composition remained proportionate in dilution series over time. This study significantly enhances our understanding of fuel behaviour in Antarctic and subantarctic waters, enabling improved predictions for estimates of sensitivities of marine organisms to toxic contaminants from fuels in the region.

  15. 油田伴生天然气回收优化的研究%Optimization for Recycle of Light Hydrocarbon of Oilfield Associated Gas

    Institute of Scientific and Technical Information of China (English)

    张亦翔; 刘畅

    2015-01-01

    针对目前油田对于伴生气回收处理设备进行了优化,改用增压泵为井口集气装置,利用涡流管在撬装设备中进行轻烃的回收,达到节能降耗和提高伴生气利用率的最终目的。%This article describes the optimization for the equipment used in recycling of associated gas in oilfields,which include using booster pump for wellhead gas collecting device and vortex tube in skid-mounted equipment for light hydrocarbon recovery, which can save energy and improve the utilization ratio of associated gas.

  16. Natural marine seepage blowout: Contribution to atmospheric methane

    OpenAIRE

    2006-01-01

    The release of methane sequestered within deep-sea methane hydrates is postulated as a mechanism for abrupt climate change; however, whether emitted seabed methane reaches the atmosphere is debatable. We observed methane emissions for a blowout from a shallow (22 m) hydrocarbon seep. The emission from the blowout was determined from atmospheric plume measurements. Simulations suggest a 1.1% gas loss to dissolution compared to ∼ 10% loss for a typical low-flux bubble plume. Transfer to the atm...

  17. Carbonate mounds from the Gulf of Cadiz in relation to methane seepage: unrelated phenomena or coupling?

    Science.gov (United States)

    Stadnitskaia, Alina; Baas, Marianne; de Haas, Henk; van Weering, Tjeerd C. E.; Kreulen, Rob R.; Sinninghe Damsté, Jaap S.

    2010-05-01

    For more than decade, the formation of carbonate mounds, related ecosystem development and organization/functioning of the entire mound habitats are subjects for a growing amount of studies and discussions. Carbonate mounds from the Gulf of Cadiz are of special interest due to their association with active mud volcanoes within the El Arraiche mud volcano field. Such co-occurrence of ecologically contrasting phenomena anticipates complex biogeochemical interactions between a carbonate mound interior and seeping through hydrocarbon-rich fluids. To get closer in understanding of how methane affects a carbonate mound development in the gulf, a combination of inorganic and organic geochemical techniques was applied to two sedimentary cores collected from summits of Alfa and Beta mounds. These mounds were found at the NW slope of the Gimini MV at the Pen Duick Mound Province. We analyzed vertical distribution profiles of sulfate, sulfide, chlorinity, DIC in combination with hydrocarbon gas measurements and lipid biomarker study. To have estimates of Sea Surface Temperature (SST) during the carbonate mound formation, we applied the TEX86 (TetraEther indeX of tetraethers with 86 carbon atoms; Schouten et al., 2002) and the alkenone-based UK37 index (Müller et al., 1998). The pore-water data revealed the presence of brine inflow, which is consistent with the data of Hensen et al., (2007). The behavior of sulfide distribution profiles and δ13C values from dissolved inorganic carbon (DIC) indicated that most of the sulfide and DIC are resulted from the microbial anaerobic oxidation of methane (AOM) processes. In contrast, the analysis of archaeal membrane lipids from distinct clades of AOM-mediating anaerobic methanotrophs showed exceedingly low concentrations of specific biomarkers, which is in contradiction with pore-water and gas chemistry data. Besides, AOM is the main cause for the increase of sedimentary alkalinity that leads to carbonate precipitation. Instead, some

  18. Renewable synthesis-gas-production. Do hydrocarbons in the reactant flow of the reverse water-gas shift reaction cause coke formation?

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, A.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    In a two-step synthetic fuel production process based on carbon dioxide and renewable hydrogen, the best possible selectivity towards liquid hydrocarbons (Hc) shall be implemented. The process consists of a combination of the Reverse Water-Gas Shift reaction and the Fischer-Tropsch synthesis. To achieve this goal, gaseous short-chained Hc from the FTS reactor are recycled in the RWGS unit. In this paper, challenges coming up with the implementation of a recycle loop are discussed. First of all, it has to be examined whether Hc are converted under conditions present in the RWGS reactor. The coking caused by the recycle of Hc is regarded, including thermal coking in the heating zone of the reactor and catalytic coking in the catalyst bed. Coking of course is unwanted, as it deactivates the catalyst. The scope of this work is to find out to which extent and under which conditions gaseous Hc can be recycled. Therefore, experiments were carried out in both, a quartz glass reactor using a commercial Ni-catalyst at ambient pressure and in a pressurized steel reactor (without catalyst) to examine coking during the thermal decomposition of Hc. The catalytic experiments at atmospheric pressure showed that a recycle of CH{sub 4} did not cause coking up to a ratio of CH{sub 4}/CO{sub 2} below one. For these conditions, long term stability was proved. The reaction rates of the CH{sub 4} conversion were below those of the RWGS reaction. However, replacing CH{sub 4} by C{sub 3}H{sub 8} leads to thermal and catalytic coking. Catalytic coking hits the maximum level at about 700 C and decreases for higher temperatures and, thus is not regarded as a problem for the RWGS reactor. In contrast to that, thermal coking raises with higher temperatures, but it can be supressed efficiently with additional injection of H{sub 2}O, which of course shifts the equilibrium towards the undesired reactant side. (orig.)

  19. Coupled Seepage and Heat Transfer Intake Model

    Institute of Scientific and Technical Information of China (English)

    WU Junhua; YOU Shijun; ZHANG Huan; LI Haishan

    2009-01-01

    In the beach well intake system, heat is transferred from soil to fluid when seawater is filtered through the aquifer, providing higher temperature source water to the seawater source heat pump (SWHP) system in winter. A 3-D coupled seepage and heat transfer model for studying beach well intake system is established by adopting the computer code FLUENT. Numerical results of this model are compared with the experimental results under the same conditions. Based on the experiment-verified coupled model, numerical simulation of the supply water temperature is studied over a heating season. Results show that the minimum temperature of supply water is 275.2 K when this intake system continuously provides seawater with flow rate of 35 m3/h to SWHP. Results also indicate that the supply water temperature is higher than seawater, and that the minimum temperature of supply water lags behind seawater, ensuring effective and reliable operation of SWHP.

  20. IDENTIFICATION OF SOME CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS IN BANGLADESHI VEHICLES EXHAUST TAR BY GAS CHROMATOGRAPHY-MASS SPECTROPHOTOMETER

    Directory of Open Access Journals (Sweden)

    M. Amzad Hossain

    2010-06-01

    Full Text Available A more sensitive GC-MS method has been established for the determination of some carcinogenic polycyclic aromatic hydrocarbons (PAHs in vehicles exhaust tar samples. The tar samples were extracted using dichloromethane (DMC: n-hexane solvent mixture. A multi-layer clean-up (silica gel/sodium sulphate column was used, followed by glass fiber filter (GFF paper. The method was successfully applied to determine a number of PAHs present in exhaust tar sample of different vehicles of the Atomic Energy Centre, Dhaka, Bangladesh.   Keywords: Carcinogenic polycyclic aromatic hydrocarbons, vehicles tar samples, identification, GC-MS/MS

  1. H-Area Seepage Basins: Groundwater quality assessment report, Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    During the second quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, nonvolatile beta, mercury, lead, cadmium, trichloroethylene chromium, and arsenic in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the H-Area Seepage Basins. Elevated levels of tritium above the PDWS were exhibited in seventy-seven of the 105 (73%) groundwater monitoring wells. Elevated levels of nitrate in excess of the PDWS were exhibited in forty-four of the 105 (42%) monitoring wells.

  2. H-Area Seepage Basins: Groundwater quality assessment report, Savannah River Site. Second quarter, 1990

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    During the second quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, nonvolatile beta, mercury, lead, cadmium, trichloroethylene chromium, and arsenic in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the H-Area Seepage Basins. Elevated levels of tritium above the PDWS were exhibited in seventy-seven of the 105 (73%) groundwater monitoring wells. Elevated levels of nitrate in excess of the PDWS were exhibited in forty-four of the 105 (42%) monitoring wells.

  3. Continuous Production Scheme of Natural Gas De-hydrocarbon When Down-stream User Using Gas Intermittently%下游间歇用气的天然气连续脱烃生产方案

    Institute of Scientific and Technical Information of China (English)

    陈炽彬

    2016-01-01

    南山终端进入下游间歇用气的小流量生产阶段后,出现了天然气烃露点控制不稳定、环境对低温脱烃系统影响加剧、恢复供气耗时长、火炬放空量大等问题。针对上述问题,对流程进行了优化改造:并联安装一个小流量副J-T阀,全面增强低温脱烃系统的保冷效果;调整生产操作方式,执行小流量供气模式。通过上述优化改造,可保持天然气连续脱烃生产,每年天然气减少排放量达到304×104 m3,实现节能增效。%Nanshan terminal is now in the low flow gas production stage with downstream user intermittent using gas, for such problems as natural gas dew point controlled unstable, environmental increased effects on low temperature de-hydrocarbon system, longer period of restored gas supply time, large amount of flare venting, etc., so an optimization scheme was taken to reengineer the flow processing. A by-pass secondary J-T valve was parallel in-stalled for low flow controlling to enhance the insulation effects of low temperature de-hy-drocarbon system; the operation procedures was adjusted to low gas supply flow mode. The result shows that natural gas de-hydrocarbon production could work continuously, the re-duction amount of flare gas emissions is 304 × 104 m3 yearly, the energy consumption is re-duced and efficiency is increased accordingly.

  4. Regional anomalies of hydrocarbon fluid saturation as a new source of data on promising oil and gas deposits in the Caspian shelf

    Science.gov (United States)

    Davydenko, D. B.

    2016-10-01

    This paper analyzes the ratio of local and regional anomalies of fluid saturation identified in the southern margins of the Eastern European Platform by remote fluid indexation. A characteristic feature of this area is the very low background values in the initial field, i.e., local anomalies reflecting the deposits. Regional anomalies are mainly related to oil and gas accumulation zones. In the Middle Caspian areas studied, the regional field of the fluid saturation index is the background for local anomalies. We made an attempt to justify the hydrocarbon migration and generation zones as anomaly-forming zones of the regional anomalies. The correlation of oil and gas accumulation zones with the regional field anomalies was noted.

  5. Analyses of firn gas samples from Dronning Maud Land, Antarctica : Study of nonmethane hydrocarbons and methyl chloride

    NARCIS (Netherlands)

    Kaspers, K.A.; Wal, R.S.W. van de; Gouw, J.A. de; Hofstede, C.M.; Broeke, M.R. van den; Veen, C. van der; Neubert, R.E.M.; Meijer, H.A.J.; Brenninkmeijer, C.A.M.; Karlöf, L.; Winther, J.G.

    2004-01-01

    Firn air was sampled on the Antarctic plateau in Dronning Maud Land (DML), during the Norwegian Antarctic Research Expedition (NARE) 2000/2001. In this paper, we describe the analyses for methyl chloride and nonmethane hydrocarbons (NMHCs) in these firn air samples. For the first time, the NMHCs eth

  6. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence J. Pekot

    2004-06-30

    Two gas storage fields were studied for this project. Overisel field, operated by Consumer's Energy, is located near the town of Holland, Michigan. Huntsman Storage Unit, operated by Kinder Morgan, is located in Cheyenne County, Nebraska near the town of Sidney. Wells in both fields experienced declining performance over several years of their annual injection/production cycle. In both fields, the presence of hydrocarbons, organic materials or production chemicals was suspected as the cause of progressive formation damage leading to the performance decline. Core specimens and several material samples were collected from these two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  7. modelingthe effect the effect of contact and seepage forces of ...

    African Journals Online (AJOL)

    eobe

    NIGERIA. 2 DEPARTMENT OF CIVIL ENGINEERING, UNIVERSITY OF NIGERIA, NSUKKA. ... This research work has investigated the contribution of contact force and seepage force to the .... iii Operational and maintenance failures. With the ...

  8. Three-dimensional stochastic seepage field for embankment engineering

    Directory of Open Access Journals (Sweden)

    Ya-jun WANG

    2009-03-01

    Full Text Available Owing to the complexity of geo-engineering seepage problems influenced by different random factors, three-dimensional simulation and analysis of the stochastic seepage field plays an important role in engineering applications. A three-dimensional anisotropic heterogeneous steady random seepage model was developed on the basis of the finite element method. A statistical analysis of the distribution characteristics of soil parameters sampled from the main embankment of the Yangtze River in the Southern Jingzhou zone of China was conducted. The Kolomogorov-Smirnov test verified the statistical hypothesis that the permeability coefficient tensor has a Gaussian distribution. With the help of numerical analysis of the stochastic seepage field using the developed model, various statistical and random characteristics of the stochastic seepage field of the main embankment of the Yangtze River in the Southern Jingzhou zone of China were investigated. The model was also examined with statistical testing. Through the introduction of random variation of the upstream and downstream water levels into the model, the effects of the boundary randomness due to variation of the downstream and upstream water levels on the variation of simulated results presented with a vector series of the random seepage field were analyzed. Furthermore, the combined influence of the variation of the soil permeability coefficient and such seepage resistance measures as the cut-off wall and relief ditch on the hydraulic head distribution was analyzed and compared with the results obtained by determinate analysis. Meanwhile, sensitivities of the hydraulic gradient and downstream exit height to the variation of boundary water level were studied. The validity of the simulated results was verified by stochastic testing and measured data. The developed model provides more detail and a full stochastic algorithm to characterize and analyze three-dimensional stochastic seepage field problems

  9. NONUNIFORM OPEN CHANNEL FLOW WITH UPWARD SEEPAGE THROUGH LOOSE BEDS

    Institute of Scientific and Technical Information of China (English)

    Subhasish DEY

    2003-01-01

    The Reynolds stress and bed shear stress are important parameters in fluvial hydraulics. Steadynonuniform flow in open channels with streamwise sloping beds having upward seepage through loose beds is theoretically analyzed to estimate the Reynolds stress and bed shear stress. Equations of the Reynolds stress and bed shear stress are developed, assuming a modified logarithmic velocity distribution law due to upward seepage, and using the Reynolds and continuity equations of twodimensional flow in open channels.

  10. Three-dimensional stochastic seepage field for embankment engineering

    Institute of Scientific and Technical Information of China (English)

    Ya-jun WANG; Wo-hua ZHANG; Chang-yu WU; Da-chun REN

    2009-01-01

    Owing to the complexity of get-engineering seepage problems influenced by different random factors, three-dimensional simulation and analysis of the stochastic seepage field plays an important role in engineering applications. A three-dimensional anisotropic heterogeneous steady random seepage model was developed on the basis of the finite element method. A statistical analysis of the distribution characteristics of soil parameters sampled from the main embankment of the Yangtze River in the Southern Jingzhou zone of China was conducted. The Kolomogorov-Smimov test verified the statistical hypothesis that the permeability coefficient tensor has a Gaussian distribution. With the help of numerical analysis of the stochastic seepage field using the developed model, various statistical and random characteristics of the stochastic seepage field of the main embankment of the Yangtze River in the Southern Jingzhou zone of China were investigated. The model was also examined with statistical testing. Through the introduction of random variation of the upstream and downstream water levels into the model, the effects of the boundary randomness due to variation of the downstream and upstream water levels on the variation of simulated results presented with a vector series of the random seepage field were analyzed. Furthermore, the combined influence of the variation of the soil permeability coefficient and such seepage resistance measures as the cut-off wall and relief ditch on the hydraulic head distribution was analyzed and compared with the results obtained by determinate analysis. Meanwhile, sensitivities of the hydraulic gradient and downstream exit height to the variation of boundary water level were studied. The validity of the simulated results was verified by stochastic testing and measured data. The developed model provides more detail and a full stochastic algorithm to characterize and analyze three-dimensional stochastic seepage field problems.

  11. Occurrence of gaseous and particulate polycyclic aromatic hydrocarbons in the urban atmosphere: study of sources and ambient temperature effect on the gas/particle concentration and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tsapakis, Manolis [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece); Stephanou, Euripides G. [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece)]. E-mail: stephanou@chemistry.uoc.gr

    2005-01-01

    The presence of polycyclic aromatic hydrocarbons (PAHs) in an urban region (Heraklion, Greece) and processes that govern their atmospheric fate were studied from November 2000 until February 2002. Sixteen samples were collected, by using an artifact-free sampling device, on a monthly basis and the concentration of PAHs in gas and particulate phase was determined. The most abundant members (gas + particles) were phenanthrene (20.0 {+-} 7.0 ng m{sup -3}), fluoranthene (6.5 {+-} 1.7 ng m{sup -3}), pyrene (6.6 {+-} 2.4 ng m{sup -3}), and chrysene (3.1 {+-} 1.5 ng m{sup -3}). Total concentration (gas + particulate) of PAH ranged from 44.3 to 129.2 ng m{sup -3}, with a mean concentration of 79.3 ng m{sup -3}. Total concentration of PAHs in gas phase ranged from 31.4 to 84.7 ng m{sup -3} with non-observable seasonal variation. Conversely, maximum PAH concentrations in the particulate phase occurred during winter months. Particulate concentration varied from 11.4 to 44.9 ng m{sup -3}, with an average of 25.2 ng m{sup -3}. PAH distribution between gas and particulate phase was in agreement with the sub-cooled vapor pressure. Shift in gas/particle distribution due to difference in ambient temperature elucidated to some extent the seasonal variation of the concentration of PAHs in particles. - Capsule: Ambient PAH partitioning between gas and particle phases vary between compounds and with environmental conditions.

  12. Development, optimization, validation and application of faster gas chromatography - flame ionization detector method for the analysis of total petroleum hydrocarbons in contaminated soils.

    Science.gov (United States)

    Zubair, Abdulrazaq; Pappoe, Michael; James, Lesley A; Hawboldt, Kelly

    2015-12-18

    This paper presents an important new approach to improving the timeliness of Total Petroleum Hydrocarbon (TPH) analysis in the soil by Gas Chromatography - Flame Ionization Detector (GC-FID) using the CCME Canada-Wide Standard reference method. The Canada-Wide Standard (CWS) method is used for the analysis of petroleum hydrocarbon compounds across Canada. However, inter-laboratory application of this method for the analysis of TPH in the soil has often shown considerable variability in the results. This could be due, in part, to the different gas chromatography (GC) conditions, other steps involved in the method, as well as the soil properties. In addition, there are differences in the interpretation of the GC results, which impacts the determination of the effectiveness of remediation at hydrocarbon-contaminated sites. In this work, multivariate experimental design approach was used to develop and validate the analytical method for a faster quantitative analysis of TPH in (contaminated) soil. A fractional factorial design (fFD) was used to screen six factors to identify the most significant factors impacting the analysis. These factors included: injection volume (μL), injection temperature (°C), oven program (°C/min), detector temperature (°C), carrier gas flow rate (mL/min) and solvent ratio (v/v hexane/dichloromethane). The most important factors (carrier gas flow rate and oven program) were then optimized using a central composite response surface design. Robustness testing and validation of model compares favourably with the experimental results with percentage difference of 2.78% for the analysis time. This research successfully reduced the method's standard analytical time from 20 to 8min with all the carbon fractions eluting. The method was successfully applied for fast TPH analysis of Bunker C oil contaminated soil. A reduced analytical time would offer many benefits including an improved laboratory reporting times, and overall improved clean up

  13. Hydrocarbon accumulation patterns of large tight oil and gas fields%论致密大油气田成藏模式

    Institute of Scientific and Technical Information of China (English)

    赵靖舟; 李军; 曹青; 白玉彬; 耳闯; 王晓梅; 肖晖; 吴伟涛

    2013-01-01

    根据对国内外致密油气聚集成藏特征的分析,提出致密大油气田存在3种成藏模式,即连续型(深盆气型)、准连续型和不连续型(常规圈闭型)。与连续型油气藏相似,准连续型油气聚集也表现为:油气分布面积较大,无明确边界,也无边底水;源、储邻近,广覆式分布;油气运移主要为非浮力驱动,运移动力主要为异常压力、扩散作用力和毛细管压力,浮力作用受限;运移的方式主要为非达西流,以涌流和扩散流为主。所不同的是:准连续型油气聚集由多个彼此相邻的中小型油气藏组成,油气呈准连续分布;油、气、水分布比较复杂,无显著油、气、水倒置;油气充注以大面积弥漫式垂向排驱为主,初次运移直接成藏或短距离二次运移成藏;储层先致密后成藏或边致密边成藏,且非均质性较强;圈闭对油气聚集成藏具有一定控制作用。研究认为,以深盆气或盆地中心气为代表的连续型油气藏与典型的不连续型常规圈闭油气藏,分别代表了复杂地质环境中致密油气藏形成序列中的两种端元类型,二者之间应存在不同的过渡类型。准连续型油气藏就是这样一种过渡类型的致密油气聚集,并且可能是致密储层中大油气田形成的主要方式。事实上,典型的连续型油气聚集应是那些形成于烃源岩内的油气聚集(如页岩气和煤层气),典型的不连续型油气聚集则是那些形成于烃源岩外近源-远源的常规储层中、受常规圈闭严格控制并且具有边底水的油气聚集;而形成于烃源岩外并且近源的致密油气藏则主要为准连续型油气聚集,其次为非典型的不连续型(常规圈闭型)油气聚集,而像盆地中心气或深盆气那样的连续型聚集则较为少见。%Three patterns of hydrocarbon accumulation in large tight oil /gas fields are

  14. Anaerobic degradation of propane and butane by sulfate-reducing bacteria enriched from marine hydrocarbon cold seeps.

    Science.gov (United States)

    Jaekel, Ulrike; Musat, Niculina; Adam, Birgit; Kuypers, Marcel; Grundmann, Olav; Musat, Florin

    2013-05-01

    The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hydrate Ridge. The enrichment cultures obtained were able to degrade simultaneously propane and butane, but not other gaseous alkanes. They were cold-adapted, showing highest sulfate-reduction rates between 16 and 20 °C. Analysis of 16S rRNA gene libraries, followed by whole-cell hybridizations with sequence-specific oligonucleotide probes showed that each enrichment culture was dominated by a unique phylotype affiliated with the Desulfosarcina-Desulfococcus cluster within the Deltaproteobacteria. These phylotypes formed a distinct phylogenetic cluster of propane and butane degraders, including sequences from environments associated with hydrocarbon seeps. Incubations with (13)C-labeled substrates, hybridizations with sequence-specific probes and nanoSIMS analyses showed that cells of the dominant phylotypes were the first to become enriched in (13)C, demonstrating that they were directly involved in hydrocarbon degradation. Furthermore, using the nanoSIMS data, carbon assimilation rates were calculated for the dominant cells in each enrichment culture.

  15. Update of on-line coupled liquid chromatography - gas chromatography for the analysis of mineral oil hydrocarbons in foods and cosmetics.

    Science.gov (United States)

    Biedermann, Maurus; Munoz, Celine; Grob, Koni

    2017-09-13

    On-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) is the most widely used method for the analysis of mineral oil hydrocarbons in food, food contact materials, tissues and cosmetics. With comprehensive two-dimensional gas chromatography (GCxGC), a tool became available for better establishing the elution sequence of the various types of hydrocarbons from the HPLC column used for isolating the mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The performance of a heavily used HPLC column with reduced retention for MOAH was investigated to improve the robustness of the method. Updates are recommended that render the MOSH/MOAH separation less dependent of the state of the HPLC column and more correct in cases of highly refined mineral oil products of high molecular mass. Cyclohexyl cyclohexane (Cycy), used as internal standard, turned out to be eluted slightly after cholestane (Cho); apparently the size exclusion effect predominates the extra retention by ring number on the 60Å pore size silica gel. Hence, Cycy can be used to determine the end of the MOSH fraction. Long chain alkyl benzenes were eluted earlier than tri-tert. butyl benzene (Tbb). It is proposed to start the MOAH transfer immediately after the MOSH fraction and use a gradient causing breakthrough of dichloromethane (visible in the UV chromatogram) at a time suitable to elute perylene (Per) at the end of the fraction. In this way, a decrease in retention power of the HPLC column can be tolerated without adjustment of the MOAH fraction until some MOAH start being eluted into the MOSH fraction. This critical point can be checked either with di(2-ethylhexyl) benzene (DEHB) as a marker or the HPLC-UV chromatogram. Finally, based on new findings in rats and human tissues, it is recommended to integrate the MOSH and MOAH up to the retention time of the n-alkane C40. Copyright © 2017 Elsevier B.V. All rights

  16. Afghan hydrocarbons: a source for development or for conflict? A risk assessment of Norwegian involvement in development of the Afghan oil and gas industry

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Arne; Hakim, Mohammad; Newrozi, Sediqa; Sarwari, Akbar; Williams, Aled

    2010-10-22

    Norad has been engaged in capacity building and provision of technical support to the Afghan Ministry of Mines since 2007. A part of this engagement relates to the development of the Afghan Hydrocarbons Law, and commercialization of gas and oil reserves through an international bidding process. The Afghan oil and gas industry has been in production since the mid 1980s, but is in need of major investments. Afghans interviewed are of the opinion that oil and gas reserves are national property, to be used for the benefit of all Afghans. The review has identified a range of risks and challenges to the further process, and Norad is advised to consider: To await further engagement on policy matters until there is further clarity as to how the Government of Afghanistan aims to develop and utilize these resources. But consider to provide: 1) Advice on the political/diplomatic process of negotiating agreements for utilization and division of underground natural resources; 2) Assist in training and development of Afghan technical expertise in oil and gas exploration, production and management; 3) Assist in the further development of the hydro power and alternative energy sector. (AG)

  17. Statistical analysis of liquid seepage in partially saturated heterogeneous fracture systems

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Tai -Sheng [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Field evidence suggests that water flow in unsaturated fracture systems may occur along fast preferential flow paths. However, conventional macroscale continuum approaches generally predict the downward migration of water as a spatially uniform wetting front subjected to strong inhibition into the partially saturated rock matrix. One possible cause of this discrepancy may be the spatially random geometry of the fracture surfaces, and hence, the irregular fracture aperture. Therefore, a numerical model was developed in this study to investigate the effects of geometric features of natural rock fractures on liquid seepage and solute transport in 2-D planar fractures under isothermal, partially saturated conditions. The fractures were conceptualized as 2-D heterogeneous porous media that are characterized by their spatially correlated permeability fields. A statistical simulator, which uses a simulated annealing (SA) algorithm, was employed to generate synthetic permeability fields. Hypothesized geometric features that are expected to be relevant for seepage behavior, such as spatially correlated asperity contacts, were considered in the SA algorithm. Most importantly, a new perturbation mechanism for SA was developed in order to consider specifically the spatial correlation near conditioning asperity contacts. Numerical simulations of fluid flow and solute transport were then performed in these synthetic fractures by the flow simulator TOUGH2, assuming that the effects of matrix permeability, gas phase pressure, capillary/permeability hysteresis, and molecular diffusion can be neglected. Results of flow simulation showed that liquid seepage in partially saturated fractures is characterized by localized preferential flow, along with bypassing, funneling, and localized ponding. Seepage pattern is dominated by the fraction of asperity contracts, and their shape, size, and spatial correlation. However, the correlation structure of permeability field is less important

  18. Chemical recycling of carbon dioxide to methanol and dimethyl ether: from greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons.

    Science.gov (United States)

    Olah, George A; Goeppert, Alain; Prakash, G K Surya

    2009-01-16

    Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time can new fossil fuels be formed naturally. In contrast, chemical recycling of carbon dioxide from natural and industrial sources as well as varied human activities or even from the air itself to methanol or dimethyl ether (DME) and their varied products can be achieved via its capture and subsequent reductive hydrogenative conversion. The present Perspective reviews this new approach and our research in the field over the last 15 years. Carbon recycling represents a significant aspect of our proposed Methanol Economy. Any available energy source (alternative energies such as solar, wind, geothermal, and atomic energy) can be used for the production of needed hydrogen and chemical conversion of CO(2). Improved new methods for the efficient reductive conversion of CO(2) to methanol and/or DME that we have developed include bireforming with methane and ways of catalytic or electrochemical conversions. Liquid methanol is preferable to highly volatile and potentially explosive hydrogen for energy storage and transportation. Together with the derived DME, they are excellent transportation fuels for internal combustion engines (ICE) and fuel cells as well as convenient starting materials for synthetic hydrocarbons and their varied products. Carbon dioxide thus can be chemically transformed from a detrimental greenhouse gas causing global warming into a valuable, renewable and inexhaustible carbon source of the future allowing environmentally neutral use of carbon fuels and derived hydrocarbon products.

  19. Rapid and sensitive solid phase extraction-large volume injection-gas chromatography for the analysis of mineral oil saturated and aromatic hydrocarbons in cardboard and dried foods.

    Science.gov (United States)

    Moret, Sabrina; Barp, Laura; Purcaro, Giorgia; Conte, Lanfranco S

    2012-06-22

    A rapid off-line solid phase extraction-large volume injection-gas chromatography-flame ionisation detection (SPE-LVI-GC-FID) method, based on the use of silver silica gel and low solvent consumption, was developed for mineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) determination in cardboard and dried foods packaged in cardboard. The SPE method was validated using LVI with a conventional on-column injector and the retention gap technique (which allowed to inject up to 50 μL of the sample). Detector response was linear over all the concentration range tested (0.5-250 μg/mL), recoveries were practically quantitative, repeatability was good (coefficients of variation lower than 7%) and limit of quantification adequate to quantify the envisioned limit of 0.15 mg/kg proposed in Germany for MOAH analysis in food samples packaged in recycled cardboard. Rapid heating of the GC oven allowed to increase sample throughput (3-4 samples per hour) and to enhance sensitivity. The proposed method was used for MOSH and MOAH determination in selected food samples usually commercialised in cardboard packaging. The most contaminated was a tea sample (102.2 and 7.9 mg/kg of MOSH and MOAH below n-C25, respectively), followed by a rice and a sugar powder sample, all packaged in recycled cardboard.

  20. Solid-phase Microextraction with Benzoxy-calix[6]arene Fiber Coupled to Gas Chromatography for the Analysis of Polycyclic Aromatic Hydrocarbons in Water

    Institute of Scientific and Technical Information of China (English)

    YE Chang-wen; ZHANG Xue-na; HUANG Jiang-yan; LI Xiu-juan; PAN Si-yi

    2011-01-01

    Headspace solid-phase microextraction(HS-SPME) with sol-gel calix[6]arene-containing fiber followed by gas chromatography with a flame ionization detector was used to examine the composition and distribution of seven polycyclic aromatic hydrocarbons(PAHs) in water. The novel SPME fiber exhibited higher extraction efficien cy to PAHs compared with poly(dimethylsiloxane) and other calixarene-containing fibers. Extraction/retention me chanism based on the interactions between calixarenes and PAHs was discussed. Owing to the good selectivity and high extraction capability of this calixarene fiber, low detection limits were obtained in a range of 0.34—6.50 ng/L and the relative standard deviation values were ≤ 12.3% for all of the analytes. The linear ranges of the proposed method were five orders of magnitude for the tested compounds, with linear correlation coefficients(r) greater than 0.998. The method was applied to the determination of polycyclic aromatic hydrocarbons in nine water sources in Wuhan City, China. Standard addition method was selected for the quantification and the recovery values were in a satisfactory range. Total PAHs concentrations in the nine surface water samples were found to vary between unde tectable and 8.840 μg/L with two-and three-ring PAHs predominating.

  1. Solid-phase microextraction and gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in environmental solid matrices.

    Science.gov (United States)

    Cam, D; Gagni, S; Lombardi, N; Punin, M O

    2004-07-01

    A solid-phase microextraction (SPME) and gas chromatography-mass spectrometry method for determining polycyclic aromatic hydrocarbons (PAHs) in environmental solid matrices is developed. Investigated matrices include seaweed (Undaria pinnatifida and Himanthalia elongata), humic substances (isolated from a wetland out-flow and purchased from Aldrich), and soil. Optimal conditions for a good SPME efficiency of 16 hydrocarbon compounds are obtained using a 100- micro m polydimethylsiloxane fiber directly immersed in aqueous carrier medium. The method is remarkable for presenting short extraction times and considerably high sensitivities. The SPME results obtained by using internal calibration give the total analyte concentration based on the identical partitioning behavior of native and spiked pollutants. The detection limits range from 0.001 to 0.1 mg of PAH per kilogram of dry matrix. SPME external calibration provides information regarding freely dissolved analytes. The detection limits range from 0.001 to 0.05 micro g of PAH per liter of carrier medium. The SPME with external calibration procedure can be applied to measure free concentrations of a target compound spiked into a carrier medium and onto a matrix. Based on a comparison of results obtained for the two samples, the partitioning of the target analyte between the matrix and the carrier medium is calculated.

  2. Can conventional bases and unsaturated hydrocarbons be converted into gas-phase superacids that are stronger than most of the known oxyacids? The role of beryllium bonds.

    Science.gov (United States)

    Yáñez, Manuel; Mó, Otilia; Alkorta, Ibon; Elguero, José

    2013-08-26

    The association of BeX2 (X: H, F, Cl) derivatives with azoles leads to a dramatic increase of their intrinsic acidity. Hence, whereas 1H-tetrazole can be considered as a typical N base in the gas phase, the complex 1H-tetrazole-BeCl2 is predicted to be, through the use of high-level G4 ab initio calculations, a nitrogen acid stronger than perchloric acid. This acidity enhancement is due to a more favorable stabilization of the deprotonated species after the beryllium bond is formed, because the deprotonated anion is a much better electron donor than the neutral species. Consequently, this is a general phenomenon that should be observed for any Lewis base, including those in which the basic site is a hydroxy group, an amino group, a carbonyl group, an aromatic N atom, a second-row atom, or the π system of unsaturated hydrocarbons. The consequence is that typical bases like aniline or formamide lead to BeX2 complexes that are stronger acids than phosphoric or chloric acids. Similarly, water, methanol, and SH2 become stronger acids than sulfuric acid, pyridine becomes a C acid almost as strong as acetic acid, and unsaturated hydrocarbons such as ethylene and acetylene become acids as strong as nitric and sulfuric acids, respectively.

  3. Influence of oil and gas field operations on spatial and temporal distributions of atmospheric non-methane hydrocarbons and their effect on ozone formation in winter

    Directory of Open Access Journals (Sweden)

    R. A. Field

    2014-09-01

    Full Text Available Emissions from oil and natural gas development during winter in the Upper Green River Basin of Wyoming are known to drive episodic ozone (O3 production. Contrasting O3 distributions were observed in the winters of 2011 and 2012, with numerous episodes in 2011 compared to none in 2012. During 2011 wintertime O3 episodes at two sites near Boulder Wyoming, situated ∼5 km apart, were observed to sometimes differ. In 2012 the lack of O3 episodes coincided with a reduction in ambient levels of total non-methane hydrocarbons (NMHC. Measurements of speciated NMHC, and other air quality parameters, were performed to better understand emission sources and to determine which compounds are most active in promoting O3 formation. Positive Matrix Factorization (PMF analyses of the data were carried out to help achieve these goals. PMF analyses revealed three contributing factors that were identified with different emission source types: factor 1, combustion/traffic; factor 2, fugitive natural gas; and factor 3, fugitive condensate. Compositional signatures of three contributing factors were identified through comparison with independently derived emission source profiles. Fugitive emissions of natural gas and of condensate were the two principal emission source types for NMHC. A water treatment and recycling facility was found to be a significant source of condensate range NMHC, in particular toluene and m+p-xylene. Emissions from water treatment have an influence upon peak O3 mixing ratios at downwind measurement sites.

  4. Distribution of Polycyclic Aromatic Hydrocarbons between the Particulate and the Gas Phase of Mainstream Cigarette Smoke in Relation to Cigarette Technological Characteristics

    Directory of Open Access Journals (Sweden)

    Kalaitzoglou M

    2014-12-01

    Full Text Available Particulate- and gas-phase polycyclic aromatic hydrocarbons (PAHs were determined in the mainstream smoke (MSS of 59 manufactured cigarette brands (commercially available brands of unknown tobacco and blend type with variable ‘tar’ yields and physical/technological characteristics. Depending on the existence/absence of filter, the ‘tar’ yield indicated on the packet, and the cigarette length and diameter, the examined cigarette brands were classified into 15 groups: non filter (NF, high (H, medium (M, light (L, super light (SL, ultra light (UL, one-tar yields (O, 100 mm long cigarettes (H-100, L-100, SL-100, UL-100, O-100, and slim cigarettes (SL-SLIM, UL-SLIM, O-SLIM. Cigarettes were smoked in a reference smoking machine equipped with glass fibre filters for collection of PAHs bound to total particulate matter (TPM, and polyurethane foam plugs (PUF for collection of gas-phase PAHs. The relationships of gas- and particulate-phase concentrations of PAHs (ng/cig with the contents of typical MSS components, such as TPM, ‘tar’, nicotine and carbon monoxide were investigated. In addition, the phase partitioning of PAHs in MSS was evaluated in relation to the technological characteristics of cigarettes.

  5. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence J. Pekot; Ron Himes

    2004-05-31

    Core specimens and several material samples were collected from two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  6. Pyrolysis-gas chromatography-mass spectrometry with electron-ionization or resonance-enhanced-multi-photon-ionization for characterization of polycyclic aromatic hydrocarbons in the Baltic Sea.

    Science.gov (United States)

    Otto, Stefan; Streibel, Thorsten; Erdmann, Sabrina; Klingbeil, Sophie; Schulz-Bull, Detlef; Zimmermann, Ralf

    2015-10-15

    Polycyclic aromatic hydrocarbons (PAH), as a part of dissolved organic matter (DOM), are environmental pollutants of the marine compartment. This study investigates the origin of PAH, which is supposed to derive mainly from anthropogenic activities, and their alteration along the salinity gradient of the Baltic Sea. Pyrolysis in combination with gas chromatography and two mass selective detectors in one measurement cycle are utilized as a tool for an efficient trace analysis of such complex samples, by which it is possible to detect degradation products of high molecular structures. Along the north-south transect of the Baltic Sea a slightly rising trend for PAH is visible. Their concentration profiles correspond to the ship traffic as a known anthropogenic source, underlined by the value of special isomer ratios such as phenanthrene and anthracene (0.31-0.45) or pyrene and fluoranthene (0.44-0.53). The detection of naphthalene and the distribution of its alkylated representatives support this statement.

  7. Simultaneous monitoring of atmospheric methane and speciated non-methane hydrocarbon concentrations using Peltier effect sub-ambient pre-concentration and gas chromatography.

    Science.gov (United States)

    Harrison, D; Seakins, P W; Lewis, A C

    2000-02-01

    Sub-ambient trapping, used to pre-concentrate atmospheric samples for non-methane hydrocarbon (NMHC) analysis by gas chromatography, can also be used to measure ambient methane concentrations. Above a sample volume of 40 ml, a dynamic equilibrium is established between ambient and trapped methane allowing for simultaneous quantitative determinations of methane and NMHC. The temperature stability of the trap is critical for quantitative methane analysis and this can be achieved by Peltier effect cooling. Simultaneous measurements of methane and NMHC reduce the equipment required for field trips and can ease the interpretation and modelling of atmospheric data. The feasibility for deployment of the system in remote locations was demonstrated by running the apparatus virtually unattended for a 5-day period. The correlations between the concentrations of methane, ethane and ethene measured during this period are discussed.

  8. Air-sea exchange and gas-particle partitioning of polycyclic aromatic hydrocarbons over the northwestern Pacific Ocean: Role of East Asian continental outflow.

    Science.gov (United States)

    Wu, Zilan; Lin, Tian; Li, Zhongxia; Jiang, Yuqing; Li, Yuanyuan; Yao, Xiaohong; Gao, Huiwang; Guo, Zhigang

    2017-11-01

    We measured 15 parent polycyclic aromatic hydrocarbons (PAHs) in atmosphere and water during a research cruise from the East China Sea (ECS) to the northwestern Pacific Ocean (NWP) in the spring of 2015 to investigate the occurrence, air-sea gas exchange, and gas-particle partitioning of PAHs with a particular focus on the influence of East Asian continental outflow. The gaseous PAH composition and identification of sources were consistent with PAHs from the upwind area, indicating that the gaseous PAHs (three-to five-ring PAHs) were influenced by upwind land pollution. In addition, air-sea exchange fluxes of gaseous PAHs were estimated to be -54.2-107.4 ng m(-2) d(-1), and was indicative of variations of land-based PAH inputs. The logarithmic gas-particle partition coefficient (logKp) of PAHs regressed linearly against the logarithmic subcooled liquid vapor pressure (logPL(0)), with a slope of -0.25. This was significantly larger than the theoretical value (-1), implying disequilibrium between the gaseous and particulate PAHs over the NWP. The non-equilibrium of PAH gas-particle partitioning was shielded from the volatilization of three-ring gaseous PAHs from seawater and lower soot concentrations in particular when the oceanic air masses prevailed. Modeling PAH absorption into organic matter and adsorption onto soot carbon revealed that the status of PAH gas-particle partitioning deviated more from the modeling Kp for oceanic air masses than those for continental air masses, which coincided with higher volatilization of three-ring PAHs and confirmed the influence of air-sea exchange. Meanwhile, significant linear regressions between logKp and logKoa (logKsa) for PAHs were observed for continental air masses, suggesting the dominant effect of East Asian continental outflow on atmospheric PAHs over the NWP during the sampling campaign. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Late diagenetic indicators of buried oil and gas

    Science.gov (United States)

    Donovan, Terrence J.; Dalziel, Mary C.

    1977-01-01

    At least three hydrocarbon seepage mechanisms are interpreted to operate over oil and gas fields. These are: (1) effusion ofh ydrocarbons through inadequate caprocks and along faults and fractures, (2) low-molecular-weight hydrocarbons dissolved in water moving vertically through capping shales as a result of a hydrodynamic or chemical potential drive, and (3) diffusion of gases dissolved in water. Combinations of these mechanisms may also occur. Seeping hydrocarbons are oxidized near the earth's surface, and the resulting carbon dioxide reacts with water producing bicarbonate ions, which combine with calcium and magnesium dissolved in ground waters to yield isotopically distinctive pore-filling carbonate cements and surface rocks. The passage of hydrocarbons and associated compounds such as hydrogen sulfide through surface rocks causes a reducing environment and consequent reduction, mobilization, and loss of iron from iron-bearing minerals commonly resulting in a discoloration. Other metals such as manganese are also mobilized and redistributed. These changes in the physical and chemical properties of surface rocks correlate with the subsurface distribution of petroleum, and potentially can be detected from both airborne and spaceborne platforms.

  10. Gas sealing efficiency of cap rocks. Pt. 1: Experimental investigations in pelitic sediment rocks. - Pt. 2: Geochemical investigations on redistribution of volatile hydrocarbons in the overburden of natural gas reservoirs; Gas sealing efficiency of cap rocks. T. 1: Experimentelle Untersuchungen in pelitischen Sedimentgesteinen. - T.2: Geochemische Untersuchungen zur Umverteilung leichtfluechtiger Kohlenwasserstoffe in den Deckschichten von Erdgaslagerstaetten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Leythaeuser; Konstanty, J.; Pankalla, F.; Schwark, L.; Krooss, B.M.; Ehrlich, R.; Schloemer, S.

    1997-09-01

    New methods and concepts for the assessment of sealing properties of cap rocks above natural gas reservoirs and of the migration behaviour of low molecular-weight hydrocarbons in sedimentary basins were developed and tested. The experimental work comprised the systematic assesment of gas transport parameters on representative samples of pelitic rocks at elevated pressure and temperature conditions, and the characterization of their sealing efficiency as cap rocks overlying hydrocarbon accumulations. Geochemical case histories were carried out to analyse the distribution of low molecular-weight hydrocarbons in the overburden of known natural gas reservoirs in NW Germany. The results were interpreted with respect to the sealing efficiency of individual cap rock lithologies and the type and extent of gas losses. (orig.) [Deutsch] Zur Beurteilung der Abdichtungseigenschaften von Caprocks ueber Gaslagerstaetten und des Migrationsverhaltens niedrigmolekularer Kohlenwasserstoffe in Sedimentbecken wurden neue Methoden und Konzepte entwickelt und angewendet. In experimentellen Arbeiten erfolgte die systematische Bestimmung von Gas-Transportparametern an repraesentativen Proben pelitischer Gesteine unter erhoehten Druck- und Temperaturbedingungen und die Charakterisierung ihrer Abdichtungseffizienz als Deckschicht ueber Kohlenwasserstofflagerstaetten. In geochemischen Fallstudien wurde die Verteilung niedrigmolekularer Kohlenwasserstoffe in den Deckschichten ueber bekannten Erdgaslagerstaetten in NW-Deutschland analysiert und im Hinblick auf die Abdichtungseffizienz einzelner Caprock-Lithologien bzw. Art und Ausmass von Gasverlusten interpretiert. (orig.)

  11. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns; Analisis de Hidrocarburos aromaticos policiclicos. I. Determinacion por cromatografia de gases con columnas capilares de vidrio de silice fundida

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M. M.; Gonzalez, D.

    1987-07-01

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs.

  12. Mantle hydrocarbons: abiotic or biotic?

    Science.gov (United States)

    Sugisaki, R; Mimura, K

    1994-06-01

    Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) arid peridotite xenoliths in alkali basalts contain heavier hydrocarbons (n-alkanes), whereas igneous rocks produced by magmas such as gabbro arid granite lack them. The occurrence of hydrocarbons indicates that they were not derived either from laboratory contamination or from held contamination; these compounds found in the mantle-derived rocks are called here "mantle hydrocarbons." The existence of hydrocarbons correlates with petrogenesis. For example, peridotite cumulates produced by magmatic differentiation lack hydrocarbons whereas peridotite xenoliths derived from the mantle contain them. Gas chromatographic-mass spectrometric records of the mantle hydrocarbons resemble those of aliphatics in meteorites and in petroleum. Features of the hydrocarbons are that (a) the mantle hydrocarbons reside mainly along grain boundaries and in fluid inclusions of minerals; (b) heavier isoprenoids such as pristane and phytane are present; and (c) delta 13C of the mantle hydrocarbons is uniform (about -27%). Possible origins for the mantle hydrocarbons are as follows. (1) They were in organically synthesized by Fischer-Tropsch type reaction in the mantle. (2) They were delivered by meteorites and comets to the early Earth. (3) They were recycled by subduction. The mantle hydrocarbons in the cases of (1) and (2) are abiogenic and those in (3) are mainly biogenic. It appears that hydrocarbons may survive high pressures and temperatures in the mantle, but they are decomposed into lighter hydrocarbon gases such as CH4 at lower pressures when magmas intrude into the crust; consequently, peridotite cumulates do not contain heavier hydrocarbons but possess hydrocarbon gases up to C4H10.

  13. Groundwater flow and heterogeneous discharge into a seepage lake

    DEFF Research Database (Denmark)

    Kazmierczak, Jolanta; Müller, Sascha; Nilsson, B.

    2016-01-01

    Groundwater discharge into a seepage lake was investigated by combining flux measurements, hydrochemical tracers, geological information, and a telescopic modeling approach using first two-dimensional (2-D) regional then 2-D local flow and flow path models. Discharge measurements and hydrochemical...... with the lake remained under seemingly steady state conditions across seasons, a high spatial and temporal heterogeneity in the discharge to the lake was observed. The results showed that part of the groundwater flowing from the west passes beneath the lake and discharges at the eastern shore, where groundwater...... springs and high discharge zones (HDZs) are observed at the lake bottom and at seepage faces adjacent to the lake. In the 2-D cross section, surface runoff from the seepage faces delivers 64% of the total groundwater inputs to the lake, and a 2 m wide offshore HDZ delivers 13%. Presence of HDZs may...

  14. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-10

    The objective of this project is to design, construct and field demonstrate a 3-MMscfd membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. The gas processed by the membrane system will meet pipeline specifications for dew point and Btu value, and the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. The BP-Amoco gas processing plant in Pascagoula, MS was finalized as the location for the field demonstration. Detailed drawings of the MTR membrane skid (already constructed) were submitted to the plant in February, 2000. However, problems in reaching an agreement on the specifications of the system compressor delayed the project significantly, so MTR requested (and was subsequently granted) a no-cost extension to the project. Following resolution of the compressor issues, the goal is to order the compressor during the first quarter of 2002, and to start field tests in mid-2002. Information from potential users of the membrane separation process in the natural gas processing industry suggests that applications such as fuel gas conditioning and wellhead gas processing are the most promising initial targets. Therefore, most of our commercialization effort is focused on promoting these applications. Requests for stream evaluations and for design and price quotations have been received through MTR's web site, from direct contact with potential users, and through announcements in industry publications. To date, about 90 commercial quotes have been supplied, and orders totaling about $1.13 million for equipment or rental of membrane units have been received.

  15. Shallow rainwater lenses in deltaic areas with saline seepage

    Directory of Open Access Journals (Sweden)

    P. G. B. de Louw

    2011-12-01

    Full Text Available In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and size. Our findings are based on different types of field measurements and detailed numerical groundwater models applied in the south-western delta of the Netherlands. By combining the applied techniques we could extrapolate measurements at point scale (groundwater sampling, temperature and electrical soil conductivity (TEC-probe measurements, electrical cone penetration tests (ECPT to field scale (continuous vertical electrical soundings (CVES, electromagnetic survey with EM31, and even to regional scale using helicopter-borne electromagnetic measurements (HEM. The measurements show a gradual mixing zone between infiltrating fresh rainwater and upward flowing saline groundwater. The mixing zone is best characterized by the depth of the centre of the mixing zone Dmix, where the salinity is half that of seepage water, and the bottom of the mixing zone Bmix, with a salinity equal to that of the seepage water (Cl-conc. 10 to 16 g l−1. Dmix is found at very shallow depth in the confining top layer, on average at 1.7 m below ground level (b.g.l., while Bmix lies about 2.5 m b.g.l. The model results show that the constantly alternating upward and downward flow at low velocities in the confining layer is the main mechanism of mixing between rainwater and saline seepage and determines the position and extent of the mixing zone (Dmix and Bmix. Recharge, seepage flux, and drainage depth are the controlling factors.

  16. The JCMT Nearby Galaxies Legacy Survey III: Comparisons of cold dust, polycyclic aromatic hydrocarbons, molecular gas, and atomic gas in NGC 2403

    CERN Document Server

    Bendo, G J; Warren, B E; Brinks, E; Butner, H M; Chanial, P; Clements, D L; Courteau, S; Irwin, J; Israel, F P; Knapen, J H; Leech, J; Matthews, H E; Muehle, S; Petitpas, G; Serjeant, S; Tan, B K; Tilanus, R P J; Usero, A; Vaccari, M; van der Werf, P; Vlahakis, C; Wiegert, T; Zhu, M

    2009-01-01

    We used 3.6, 8.0, 70, 160 micron Spitzer Space Telescope data, James Clerk Maxwell Telescope HARP-B CO J=(3-2) data, National Radio Astronomy Observatory 12 meter telescope CO J=(1-0) data, and Very Large Array HI data to investigate the relations among PAHs, cold (~20 K) dust, molecular gas, and atomic gas within NGC 2403, an SABcd galaxy at a distance of 3.13 Mpc. The dust surface density is mainly a function of the total (atomic and molecular) gas surface density and galactocentric radius. The gas-to-dust ratio monotonically increases with radius, varying from ~100 in the nucleus to ~400 at 5.5 kpc. The slope of the gas-to-dust ratio is close to that of the oxygen abundance, suggesting that metallicity strongly affects the gas-to-dust ratio within this galaxy. The exponential scale length of the radial profile for the CO J=(3-2) emission is statistically identical to the scale length for the stellar continuum-subtracted 8 micron (PAH 8 micron) emission. However, CO J=(3-2) and PAH 8 micron surface brightne...

  17. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; T. Hofmann; J. Kaschemekat; K.A. Lokhandwala; Membrane Group; Module Group; Systems Group

    2001-01-11

    The objective of this project is to design, construct and field demonstrate a 3-MMscfd membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world conditions is required to convince industry users of the efficiency and reliability of the process. The system will be designed and fabricated by Membrane Technology and Research, Inc. (MTR) and then installed and operated at British Petroleum (BP)-Amoco's Pascagoula, MS plant. The Gas Research Institute will partially support the field demonstration and BP-Amoco will help install the unit and provide onsite operators and utilities. The gas processed by the membrane system will meet pipeline specifications for dewpoint and Btu value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. At the end of this demonstration project the process will be ready for commercialization. The route to commercialization will be developed during this project and may involve collaboration with other companies already servicing the natural gas processing industry.

  18. FIELD DEMONSTRATION OF A MEMBRANE PROCESS TO RECOVER HEAVY HYDROCARBONS AND TO REMOVE WATER FROM NATURAL GAS

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; R. Hofmann; K.A. Lokhandwala

    2003-02-14

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world conditions would convince industry users of the efficiency and reliability of the process. The system has been designed and fabricated by Membrane Technology and Research, Inc. (MTR) and will be installed and operated at British Petroleum (BP)-Amoco's Pascagoula, MS plant. The Gas Research Institute will partially support the field demonstration and BP-Amoco will help install the unit and provide onsite operators and utilities. The gas processed by the membrane system will meet pipeline specifications for dewpoint and Btu value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. At the end of this demonstration project the process will be ready for commercialization. The route to commercialization will be developed during this project and may involve collaboration with other companies already servicing the natural gas processing industry.

  19. Field Demonstration of a Membrane Process to Recover Heavy Hydrocarbons and to Remove Water from Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; T. Hofmann; K. A. Lokhandwala

    2006-09-29

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world high-pressure conditions is being conducted to convince industry users of the efficiency and reliability of the process. The system was designed and fabricated by Membrane Technology and Research, Inc. (MTR) and installed and operated at BP Amoco's Pascagoula, MS plant. The Gas Research Institute is partially supporting the field demonstration and BP-Amoco helped install the unit and provides onsite operators and utilities. The gas processed by the membrane system meets pipeline specifications for dew point and BTU value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. During the course of this project, MTR has sold 13 commercial units related to the field test technology, and by the end of this demonstration project the process will be ready for broader commercialization. A route to commercialization has been developed during this project and involves collaboration with other companies already servicing the natural gas processing industry.

  20. Field Demonstration of a Membrane Process to Recover Heavy Hydrocarbons and to Remove Water from Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; T. Hofmann; K. A. Lokhandwala

    2004-09-29

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world conditions would convince industry users of the efficiency and reliability of the process. The system has been designed and fabricated by Membrane Technology and Research, Inc. (MTR) and will be installed and operated at British Petroleum (BP)-Amoco's Pascagoula, MS plant. The Gas Research Institute will partially support the field demonstration and BP-Amoco will help install the unit and provide onsite operators and utilities. The gas processed by the membrane system will meet pipeline specifications for dewpoint and BTU value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. At the end of this demonstration project the process will be ready for commercialization. The route to commercialization will be developed during this project and may involve collaboration with other companies already servicing the natural gas processing industry.

  1. Field Demonstration of a Membrane Process to Recover Heavy Hydrocarbons and to Remove Water from Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    Kaaeid Lokhandwala

    2007-03-30

    The objective of this project was to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world high-pressure conditions was conducted to convince industry users of the efficiency and reliability of the process. The system was designed and fabricated by Membrane Technology and Research, Inc. (MTR) and installed and operated at BP Amoco's Pascagoula, MS plant. The Gas Research Institute partially supported the field demonstration and BP-Amoco helped install the unit and provide onsite operators and utilities. The gas processed by the membrane system meets pipeline specifications for dew point and BTU value and can be delivered without further treatment to the pipeline. During the course of this project, MTR has sold thirteen commercial units related to the field test technology. Revenue generated from new business is already more than four times the research dollars invested in this process by DOE. The process is ready for broader commercialization and the expectation is to pursue the commercialization plans developed during this project, including collaboration with other companies already servicing the natural gas processing industry.

  2. Field Demonstration of a Membrane Process to Recover Heavy Hydrocarbons and to Remove Water from Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    R. Baker; T. Hofmann; K. A. Lokhandwala

    2005-09-29

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGL) and remove water from raw natural gas. An extended field test to demonstrate system performance under real-world high-pressure conditions is being conducted to convince industry users of the efficiency and reliability of the process. The system was designed and fabricated by Membrane Technology and Research, Inc. (MTR) and installed and operated at BP Amoco's Pascagoula, MS plant. The Gas Research Institute is partially supporting the field demonstration and BP-Amoco helped install the unit and provided onsite operators and utilities. The gas processed by the membrane system meets pipeline specifications for dewpoint and BTU value and can be delivered without further treatment to the pipeline. Based on data from prior membrane module tests, the process is likely to be significantly less expensive than glycol dehydration followed by propane refrigeration, the principal competitive technology. During the course of this project, MTR has sold 11 commercial units related to the field test technology, and by the end of this demonstration project the process will be ready for broader commercialization. A route to commercialization has been developed during this project and involves collaboration with other companies already servicing the natural gas processing industry.

  3. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    OpenAIRE

    Jiin-Shuh Jean; Chieh-Hou Yang; Ming-Jer Lee; Ming-Kuo Lee; Ming-Hung Chien

    2008-01-01

    Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks). More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surfac...

  4. A supermolecular building layer approach for gas separation and storage applications: The eea and rtl MOF platforms for CO2 capture and hydrocarbon separation

    KAUST Repository

    Chen, Zhijie

    2015-01-01

    The supermolecular building layer (SBL) approach was employed to deliberately synthesize five novel metal-organic frameworks (1-5) with an exposed array of amide or amine functionalities within their pore system. The ability to decorate the pores with nitrogen donor moieties offers potential to evaluate/elucidate the structure-adsorption property relationship. Two MOF platforms, eea-MOF and rtl-MOF, based on pillaring of kgm-a or sql-a layers with heterofunctional 3-connected organic building blocks were targeted and constructed to purposely introduce and expose the desired amide or amine functionalities. Interestingly, gas adsorption properties of eea-MOF-4 (1) and eea-MOF-5 (2) showed that by simply altering the nitrogen donor position within the ligand, it is possible to relatively reduce the pore size of the related eea-MOF material and subsequently increase the associated CO2 uptake. The slightly confined pore space in 2, relative to 1, has enabled an enhancement of the pore local charge density and thus the observed relative increase in the CO2 and H2 isosteric heat of adsorption (Qst). In addition, light hydrocarbon adsorption studies revealed that 2 is more selective toward C2H6 and C3H8 over CH4 than 1, as exemplified for C2H6:CH4 (5:95) or C3H8:CH4 (5:95) binary gas mixtures. This journal is

  5. Detailed elucidation of hydrocarbon contamination in food products by using solid-phase extraction and comprehensive gas chromatography with dual detection.

    Science.gov (United States)

    Purcaro, Giorgia; Tranchida, Peter Q; Barp, Laura; Moret, Sabrina; Conte, Lanfranco S; Mondello, Luigi

    2013-04-22

    The present work is focused on the development/optimization of a comprehensive two-dimensional gas chromatography method, with dual detection [flame ionization (FID) and mass spectrometric], for the simultaneous identification and quantification of mineral-oil contaminants in a variety of food products. The two main classes of contaminants, namely saturated and aromatic hydrocarbons, were previously fractionated on a manually-packed silver silica solid-phase extraction (SPE) cartridge. The quantitative results were compared with those obtained by performing a large volume injection, in a GC-FID system, after the same SPE process and by an on-line liquid-gas chromatography method, with very similar results observed. The presence of a series of unknown compounds, that appeared when using the off-line methods, was investigated using the mass spectrometric data, and were tentatively-identified as esterified fatty acids, most probably derived from vegetable oil based ink. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Occurrence and palaeoenvironmental significance of aromatic hydrocarbon biomarkers in Oligocene sediments from the Mallik 5L-38 Gas Hydrate Production Research Well (Canada)

    Energy Technology Data Exchange (ETDEWEB)

    Haberer, R.M.; Mangelsdorf, K.; Wilkes, H.; Horsfield, B. [Geoforschungszentrum Potsdam, Potsdam (Germany)

    2006-07-01

    The aromatic hydrocarbon biomarker distributions of thirty Oligocene sediment samples with different lithology (lignite, clay and sand) from the JAPEX/JNOC/GSC et al. Mallik 5L-38 Gas Hydrate Production Research Well, Canada, were analyzed using gas chromatography-mass spectrometry (GC-MS). The compositions vary with lithology, indicating a change in palaeoenvironmental conditions at the time of deposition. Aromatic diterpenoids of the abietane type are more abundant in the lignite samples than in the clay samples and represent a gymnosperm (e.g., conifer) dominated palaeovegetation. In contrast, in the clay samples aromatic triterpenoids are generally preserved as major constituents, indicating angiosperm dominated vegetation. The sand samples contain only minor amounts of aromatic terpenoids, but show a preference for diterpenoid gymnosperm markers. To recognise gymnosperm versus angiosperm dominated palaeoenvironments a new ratio, termed the angiosperm-gymnosperm aromatic ratio (AGAR), has been developed. Thus, the terpenoid distribution in the deltaic sediments provides information on the compositional changes in the plant community at the Mallik site (lignites) and the hinterland (clays) over time. Concomitantly, the changing dominance in the plant communities allows an insight into varying climatic conditions during the late Oligocene in the area.

  7. A supermolecular building layer approach for gas separation and storage applications: the eea and rtl MOF platforms for CO 2 capture and hydrocarbon separation

    KAUST Repository

    Chen, Zhijie

    2015-02-11

    The supermolecular building layer (SBL) approach was employed to deliberately synthesize five novel metal–organic frameworks (1–5) with an exposed array of amide or amine functionalities within their pore system. The ability to decorate the pores with nitrogen donor moieties offers potential to evaluate/elucidate the structure–adsorption property relationship. Two MOF platforms, eea-MOF and rtl-MOF, based on pillaring of kgm-a or sql-a layers with heterofunctional 3-connected organic building blocks were targeted and constructed to purposely introduce and expose the desired amide or amine functionalities. Interestingly, gas adsorption properties of eea-MOF-4 (1) and eea-MOF-5 (2) showed that by simply altering the nitrogen donor position within the ligand, it is possible to relatively reduce the pore size of the related eea-MOF material and subsequently increase the associated CO2 uptake. The slightly confined pore space in 2, relative to 1, has enabled an enhancement of the pore local charge density and thus the observed relative increase in the CO2 and H2 isosteric heat of adsorption (Qst). In addition, light hydrocarbon adsorption studies revealed that 2 is more selective toward C2H6 and C3H8 over CH4 than 1, as exemplified for C2H6 : CH4 (5 : 95) or C3H8 : CH4 (5 : 95) binary gas mixtures.

  8. Heterogeneous seepage at the Nopal I natural analogue site, Chihuahua, Mexico

    Science.gov (United States)

    Dobson, Patrick F.; Ghezzehei, Teamrat A.; Cook, Paul J.; Rodríguez-Pineda, J. Alfredo; Villalba, Lourdes; de La Garza, Rodrigo

    2012-02-01

    A study of seepage occurring in an adit at the Nopal I uranium mine in Chihuahua, Mexico, was conducted as part of an integrated natural analogue study to evaluate the effects of infiltration and seepage on the mobilization and transport of radionuclides. An instrumented seepage collection system and local automated weather station permit direct correlation between local precipitation events and seepage. Field observations recorded between April 2005 and December 2006 indicate that seepage is highly heterogeneous with respect to time, location, and quantity. Seepage, precipitation, and fracture data were used to test two hypotheses: (1) that fast flow seepage is triggered by large precipitation events, and (2) that an increased abundance of fractures and/or fracture intersections leads to higher seepage volumes. A few zones in the back adit recorded elevated seepage volumes immediately following large (>20 mm/day) precipitation events, with transit times of less than 4 h through the 8-m thick rock mass. In most locations, there is a 1-6 month time lag between the onset of the rainy season and seepage, with longer times observed for the front adit. There is a less clear-cut relation between fracture abundance and seepage volume; processes such as evaporation and surface flow along the ceiling may also influence seepage.

  9. Validation of analytical conditions for determination of polycyclic aromatic hydrocarbons in roasted coffee by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Guatemala-Morales, Guadalupe María; Beltrán-Medina, Elisa Alejandra; Murillo-Tovar, Mario Alfonso; Ruiz-Palomino, Priscilla; Corona-González, Rosa Isela; Arriola-Guevara, Enrique

    2016-04-15

    Polycyclic aromatic hydrocarbons (PAHs) are of significant interest due to their genotoxicity in humans. PAHs quantification in coffee is complex since some of its compounds interfere in the chromatographic analysis, which hinders the reliable determination of the PAHs. Analytical conditions for the ultrasound extraction, purification and quantification of 16 PAHs in roasted coffee were studied. The better extraction efficiency of benzo[a]pyrene (68%) from ground-roasted coffee was achieved with a solvent ratio of Hex:MC (9:1 v/v) and three extraction periods of 20 min, followed by alkaline saponification and purification of the extracts. The detection limits were 0.85-39.32 ng mL(-1), and the quantification limits from 2.84 to 131.05 ng mL(-1), obtained for fluoranthene and chrysene, respectively. The extraction was effective for most of the analytes, with recoveries of 39.8% dibenzo[ah]anthracene and 69.0% benzo[b]fluoranthene. For coffee roasted in a spouted bed reactor, the summation of the 16 PAHs ranged from 3.5 to 16.4 μg kg(-1).

  10. Analysis of pure tar substances (polycyclic aromatic hydrocarbons) in the gas stream using ultraviolet visible (UV-Vis) spectroscopy and multivariate curve resolution (MCR).

    Science.gov (United States)

    Weide, Tobias; Guschin, Viktor; Becker, Wolfgang; Koelle, Sabine; Maier, Simon; Seidelt, Stephan

    2015-01-01

    The analysis of tar, mostly characterized as polycyclic aromatic hydrocarbons (PAHs), describes a topic that has been researched for years. An online analysis of tar in the gas stream in particular is needed to characterize the tar conversion or formation in the biomass gasification process. The online analysis in the gas is carried out with ultraviolet-visible (UV-Vis) spectroscopy (190-720 nm). This online analysis is performed with a measuring cell developed by the Fraunhofer Institute for Chemical Technology (ICT). To this day, online tar measurements using UV-Vis spectroscopy have not been carried out in detail. Therefore, PAHs are analyzed as follows. The measurements are split into different steps. The first step to prove the online method is to vaporize single tar substances. These experiments show that a qualitative analysis of PAHs in the gas stream with the used measurement setup is possible. Furthermore, it is shown that the method provides very exact results, so that a differentiation of various PAHs is possible. The next step is to vaporize a PAH mixture. This step consists of vaporizing five pure substances almost simultaneously. The interpretation of the resulting data is made using a chemometric interpretation method, the multivariate curve resolution (MCR). The verification of the calculated results is the main aim of this experiment. It has been shown that the tar mixture can be analyzed qualitatively and quantitatively (in arbitrary units) in detail using the MCR. Finally it is the main goal of this paper to show the first steps in the applicability of the UV-Vis spectroscopy and the measurement setup on online tar analysis in view of characterizing the biomass gasification process. Due to that, the gasification plant (at the laboratory scale), developed and constructed by the Fraunhofer ICT, has been used to vaporize these substances. Using this gasification plant for the experiments enables the usage of the measurement setup also for the

  11. Methane budget of a large gas hydrate province offshore Georgia, Black Sea

    Energy Technology Data Exchange (ETDEWEB)

    Haeckel, M.; Reitz, A.; Klaucke, I. [Leibniz Inst. of Marine Sciences, Kiel (Germany)

    2008-07-01

    Methane is the most common hydrocarbon in marine sediments. As such, all seas and oceans have methane seepage that comprises the flow of gases and natural fluids from rocks and sediments through the seabed into the water column. The main effect of methane seepage on the biosphere is the support of cold seep communities by methane and the production of hydrogen sulfide. Hydrogen sulfide is produced in the subsurface sediments by anaerobic oxidation of methane (AOM) by a consortia of microbes and is then utilized by sulfide-oxidizing microbes. This paper reported on a study that investigated methane turnover in the surface sediments in the Batumi methane seep area in the Black Sea, offshore Georgia. The methane flux budget was determined by connecting the calculated methane sinks and sources to the gas bubble motion through the surface sediments. The calculation of methane sinks included benthic flux, AOM and hydrate formation, while the sources included the gas dissolution rate. Geochemical analyses revealed a microbial origin of the methane and a shallow fluid source. Although anaerobic methane oxidation rapidly consumed the SO4{sup 2-} within the top 5-20 cm, a large upward fluid advection was not observed in the porewater profiles. Therefore, it was determined that the Batumi seep area is dominated by methane gas seepage. 1-D transport-reaction modelling constrains the methane flux needed to support the observed SO4{sup 2-} flux as well as the rate of near-surface hydrate formation. The model results were in good agreement with the hydro-acoustic backscatter intensities observed at the bubble release sites using the sonar of a ROV. 52 refs., 1 tab., 4 figs.

  12. Geophysical investigation of seepage beneath an earthen dam.

    Science.gov (United States)

    Ikard, S J; Rittgers, J; Revil, A; Mooney, M A

    2015-01-01

    A hydrogeophysical survey is performed at small earthen dam that overlies a confined aquifer. The structure of the dam has not shown evidence of anomalous seepage internally or through the foundation prior to the survey. However, the surface topography is mounded in a localized zone 150 m downstream, and groundwater discharges from this zone periodically when the reservoir storage is maximum. We use self-potential and electrical resistivity tomography surveys with seismic refraction tomography to (1) determine what underlying hydrogeologic factors, if any, have contributed to the successful long-term operation of the dam without apparent indicators of anomalous seepage through its core and foundation; and (2) investigate the hydraulic connection between the reservoir and the seepage zone to determine whether there exists a potential for this success to be undermined. Geophysical data are informed by hydraulic and geotechnical borehole data. Seismic refraction tomography is performed to determine the geometry of the phreatic surface. The hydro-stratigraphy is mapped with the resistivity data and groundwater flow patterns are determined with self-potential data. A self-potential model is constructed to represent a perpendicular profile extending out from the maximum cross-section of the dam, and self-potential data are inverted to recover the groundwater velocity field. The groundwater flow pattern through the aquifer is controlled by the bedrock topography and a preferential flow pathway exists beneath the dam. It corresponds to a sandy-gravel layer connecting the reservoir to the downstream seepage zone.

  13. The analysis of physicochemical characteristics of pig farm seepage ...

    African Journals Online (AJOL)

    Dikonketso Matjuda

    based on the analyses of the physicochemical parameters of the adjacent environments. ... Author(s) agree that this article remain permanently open access under the terms of the Creative ... store their seepage in lagoons for a long time and this ...... Correlation of soil physico-chemical factors with vam fungi distribution.

  14. Determination of polycyclic aromatic hydrocarbons (PAHs). gas chromatographic method; Determinazione degli idrocarburi policiclici aromatici (IPA). Metodo gascaromatografico

    Energy Technology Data Exchange (ETDEWEB)

    Menichini, E.; Viviano, G. [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Igiene Ambientale

    1997-12-01

    The method enables the determination of 4- to 6- ring PAHs and particularly of carcinogenic PAHs regulated in Italy. This revision is based on the results of a national collaborative study. Sample extract, obtained by a method described in a previous report (Rapporto ISTISAN: 90/33) is cleaned up by thin layer chromatography and analysed by gas chromatography; identification is confirmed by mass spectrometry. An intralaboratory quality control program is described.

  15. Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle.

    Science.gov (United States)

    Lea-Smith, David J; Biller, Steven J; Davey, Matthew P; Cotton, Charles A R; Perez Sepulveda, Blanca M; Turchyn, Alexandra V; Scanlan, David J; Smith, Alison G; Chisholm, Sallie W; Howe, Christopher J

    2015-11-03

    Hydrocarbons are ubiquitous in the ocean, where alkanes such as pentadecane and heptadecane can be found even in waters minimally polluted with crude oil. Populations of hydrocarbon-degrading bacteria, which are responsible for the turnover of these compounds, are also found throughout marine systems, including in unpolluted waters. These observations suggest the existence of an unknown and widespread source of hydrocarbons in the oceans. Here, we report that strains of the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus, produce and accumulate hydrocarbons, predominantly C15 and C17 alkanes, between 0.022 and 0.368% of dry cell weight. Based on global population sizes and turnover rates, we estimate that these species have the capacity to produce 2-540 pg alkanes per mL per day, which translates into a global ocean yield of ∼ 308-771 million tons of hydrocarbons annually. We also demonstrate that both obligate and facultative marine hydrocarbon-degrading bacteria can consume cyanobacterial alkanes, which likely prevents these hydrocarbons from accumulating in the environment. Our findings implicate cyanobacteria and hydrocarbon degraders as key players in a notable internal hydrocarbon cycle within the upper ocean, where alkanes are continually produced and subsequently consumed within days. Furthermore we show that cyanobacterial alkane production is likely sufficient to sustain populations of hydrocarbon-degrading bacteria, whose abundances can rapidly expand upon localized release of crude oil from natural seepage and human activities.

  16. Noble gas constraints on hydrocarbon accumulation and groundwater flow in the central area of Western Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    樊然学

    2001-01-01

    The noble gas concentrations and isotope ratios of seven natural gas samples from the central area of the Western Sichuan Basin were measured. The samples all have 40Ar/36Ar ratios greater than the atmospheric values, and the 3He/4He ratios (R/Ra) are entirely consistent with the crustal radiogenic He values. The vertical variation of the calculated CH4/36Ar ratios with depth clearly indicates that the CH4and 36Ar are intimately associated, indicating a common reservoir intermediate to the sampled reservoirs, where they are well mixed and stored together prior to entrapment into gas reservoirs. Meanwhile, the calculated CH4/36Ar ratios range between 8×106 and 64×106 very much greater than the CH4/36Ar values for pure water and 5 mol/L NaCI brine at low temperature and hydrostatic conditions, reflecting the presence of "excess" thermogenic CH4 over that supplied by a CH4-saturated groundwater at low temperature, and the excess CH4 saturation and dissolution to be at depth greater than the sampled reserv

  17. Kinetic Models Study of Hydrogenation of Aromatic Hydrocarbons in Vacuum Gas Oil and Basrah Crude Oil Reaction

    Directory of Open Access Journals (Sweden)

    Muzher M. Ibraheem

    2013-05-01

    Full Text Available             The aim of this research is to study the kinetic reaction models for catalytic hydrogenation of aromatic content for Basrah crude oil (BCO and vacuum gas oil (VGO derived from Kirkuk crude oil which has the boiling point rang of (611-833K.            This work is performed using a hydrodesulphurization (HDS pilot plant unit located in AL-Basil Company. A commercial (HDS catalyst cobalt-molybdenum (Co-Mo supported in alumina (γ-Al2O3 is used in this work. The feed is supplied by North Refinery Company in Baiji. The reaction temperatures range is (600-675 K over liquid hourly space velocity (LHSV range of (0.7-2hr-1 and hydrogen pressure is 3 MPa with H2/oil ratio of 300 of Basrah Crude oil (BCO, while the corresponding conditions for vacuum gas oil (VGO are (583-643 K, (1.5-3.75 hr-1, 3.5 MPa and 250  respectively .            The results showed that the reaction kinetics is of second order for both types of feed. Activation energies are found to be 30.396, 38.479 kJ/mole for Basrah Crude Oil (BCO and Vacuum Gas Oil (VGO respectively.

  18. Field Demonstration of a Membrane Process to Recover Heavy Hydrocarbons and to Remove Water from Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    Kaaeid Lokhandwala

    2003-09-29

    The objective of this project is to design, construct and field demonstrate a membrane system to recover natural gas liquids (NGLs) and remove water from raw natural gas. To convince industry users of the efficiency and reliability of the process, we plan to conduct an extended field test to demonstrate system performance under real-world conditions. The membrane system has been designed and fabricated by Membrane Technology and Research, Inc. (MTR). The MTR membrane system and the compressor are now onsite at BP's Pascagoula, MS plant. The plant is undergoing a very significant expansion and the installation of the membrane unit into the test location is being implemented, albeit at a slower rate than we expected. The startup of the system and conducting of tests will occur in the next six months, depending on the availability of the remaining budget. In the interim, significant commercial progress has been made regarding the introduction of the NGL membrane and systems into the natural gas market.

  19. Paleozoic Hydrocarbon-Seep Limestones

    Science.gov (United States)

    Peckmann, J.

    2007-12-01

    To date, five Paleozoic hydrocarbon-seep limestones have been recognized based on carbonate fabrics, associated fauna, and stable carbon isotopes. These are the Middle Devonian Hollard Mound from the Antiatlas of Morocco [1], Late Devonian limestone lenses with the dimerelloid brachiopod Dzieduszyckia from the Western Meseta of Morocco [2], Middle Mississippian limestones with the dimerelloid brachiopod Ibergirhynchia from the Harz Mountains of Germany [3], Early Pennsylvanian limestones from the Tantes Mound in the High Pyrenees of France [4], and Late Pennsylvanian limestone lenses from the Ganigobis Shale Member of southern Namibia [5]. Among these examples, the composition of seepage fluids varied substantially as inferred from delta C-13 values of early diagenetic carbonate phases. Delta C-13 values as low as -50 per mil from the Tantes Mound and -51 per mil from the Ganigobis limestones reveal seepage of biogenic methane, whereas values of -12 per mil from limestones with Dzieduszyckia associated with abundant pyrobitumen agree with oil seepage. Intermediate delta C-13 values of carbonate cements from the Hollard Mound and Ibergirhynchia deposits probably reflect seepage of thermogenic methane. It is presently very difficult to assess the faunal evolution at seeps in the Paleozoic based on the limited number of examples. Two of the known seeps were typified by extremely abundant rhynchonellide brachiopods of the superfamily Dimerelloidea. Bivalve mollusks and tubeworms were abundant at two of the known Paleozoic seep sites; one was dominated by bivalve mollusks (Hollard Mound, Middle Devonian), another was dominated by tubeworms (Ganigobis Shale Member, Late Pennsylvanian). The tubeworms from these two deposits are interpreted to represent vestimentiferan worms, based on studies of the taphonomy of modern vestimentiferans. However, this interpretation is in conflict with the estimated evolutionary age of vestimentiferans based on molecular clock methods

  20. Analytical Modeling of Groundwater Seepages to St. Lucie Estuary

    Science.gov (United States)

    Lee, J.; Yeh, G.; Hu, G.

    2008-12-01

    In this paper, six analytical models describing hydraulic interaction of stream-aquifer systems were applied to St Lucie Estuary (SLE) River Estuaries. These are analytical solutions for: (1) flow from a finite aquifer to a canal, (2) flow from an infinite aquifer to a canal, (3) the linearized Laplace system in a seepage surface, (4) wave propagation in the aquifer, (5) potential flow through stratified unconfined aquifers, and (6) flow through stratified confined aquifers. Input data for analytical solutions were obtained from monitoring wells and river stages at seepage-meter sites. Four transects in the study area are available: Club Med, Harbour Ridge, Lutz/MacMillan, and Pendarvis Cove located in the St. Lucie River. The analytical models were first calibrated with seepage meter measurements and then used to estimate of groundwater discharges into St. Lucie River. From this process, analytical relationships between the seepage rate and river stages and/or groundwater tables were established to predict the seasonal and monthly variation in groundwater seepage into SLE. It was found the seepage rate estimations by analytical models agreed well with measured data for some cases but only fair for some other cases. This is not unexpected because analytical solutions have some inherently simplified assumptions, which may be more valid for some cases than the others. From analytical calculations, it is possible to predict approximate seepage rates in the study domain when the assumptions underlying these analytical models are valid. The finite and infinite aquifer models and the linearized Laplace method are good for sites Pendarvis Cove and Lutz/MacMillian, but fair for the other two sites. The wave propagation model gave very good agreement in phase but only fairly agreement in magnitude for all four sites. The stratified unconfined and confined aquifer models gave similarly good agreements with measurements at three sites but poorly at the Club Med site. None of

  1. Delineating gas bearing reservoir by using spectral decomposition attribute: Case study of Steenkool formation, Bintuni Basin

    Science.gov (United States)

    Haris, A.; Pradana, G. S.; Riyanto, A.

    2017-07-01

    Tectonic setting of the Bird Head Papua Island becomes an important model for petroleum system in Eastern part of Indonesia. The current exploration has been started since the oil seepage finding in Bintuni and Salawati Basin. The biogenic gas in shallow layer turns out to become an interesting issue in the hydrocarbon exploration. The hydrocarbon accumulation appearance in a shallow layer with dry gas type, appeal biogenic gas for further research. This paper aims at delineating the sweet spot hydrocarbon potential in shallow layer by applying the spectral decomposition technique. The spectral decomposition is decomposing the seismic signal into an individual frequency, which has significant geological meaning. One of spectral decomposition methods is Continuous Wavelet Transform (CWT), which transforms the seismic signal into individual time and frequency simultaneously. This method is able to make easier time-frequency map analysis. When time resolution increases, the frequency resolution will be decreased, and vice versa. In this study, we perform low-frequency shadow zone analysis in which the amplitude anomaly at a low frequency of 15 Hz was observed and we then compare it to the amplitude at the mid (20 Hz) and the high-frequency (30 Hz). The appearance of the amplitude anomaly at a low frequency was disappeared at high frequency, this anomaly disappears. The spectral decomposition by using CWT algorithm has been successfully applied to delineate the sweet spot zone.

  2. Impact of aquifer desaturation on steady-state river seepage

    Science.gov (United States)

    Morel-Seytoux, Hubert J.; Miracapillo, Cinzia; Mehl, Steffen

    2016-02-01

    Flow exchange between surface and ground water is of great importance be it for beneficial allocation and use of the water resources or for the proper exercise of water rights. That exchange can take place under a saturated or unsaturated flow regime. Which regimes occur depend on conditions in the vicinity of the interactive area. Withdrawals partially sustained by seepage may not bring about desaturation but greater amounts eventually will. The problem considered in this paper deals only with the steady-state case. It is meant as a first step toward a simple, yet accurate and physically based treatment of the transient situation. The primary purpose of the article is to provide simple criteria for determination of the initiation of desaturation in an aquifer originally in saturated hydraulic connection with a river or a recharge area. The extent of the unsaturated zone in the aquifer will increase with increasing withdrawals while at the same time the seepage rate from the river increases. However the seepage increase will stop once infiltration takes place strictly by gravity in the aquifer and is no longer opposed by the capillary rise from the water table below the riverbed. Following desaturation simple criteria are derived and simple analytical formulae provided to estimate the river seepage based on the position of the water table mound below the clogging layer and at some distance away from the river bank. They fully account for the unsaturated flow phenomena, including the existence of a drainage entry pressure. Two secondary objectives were to verify that (1) the assumption of uniform vertical flow through a clogging layer and that (2) the approximation of the water table mound below the seepage area as a flat surface were both reasonably legitimate. This approach will be especially advantageous for the implementation of the methodology in large-scale applications of integrated hydrologic models used for management.

  3. Nonlinear analysis for the coupled problem of temperature and seepage fields in cold regions tunnels

    Institute of Scientific and Technical Information of China (English)

    赖远明; 吴紫汪; 朱元林; 何春雄; 朱林楠

    1999-01-01

    The governing differential equations of the coupled problem of temperature and seepage fields with phase change are first derived from the theory of heat transfer and the theory of seepage. The finite element formulae of this problem are obtained from Galerkin’ s method. And considering the seepage influence, an illustrative example of thetemperature field in a cold-region tunnel is provided.The example shows that the influence of seepage on the frozen depth of the tunnel is very great, and thus the effect of the seepage factor should be taken into account in the engineering design.

  4. Estimation of gas-particle partitioning coefficients (Kp) of carcinogenic polycyclic aromatic hydrocarbons in carbonaceous aerosols collected at Chiang-Mai, Bangkok and Hat-Yai, Thailand.

    Science.gov (United States)

    Pongpiachan, Siwatt; Ho, Kin Fai; Cao, Junji

    2013-01-01

    To assess environmental contamination with carcinogens, carbonaceous compounds, water-soluble ionic species and trace gaseous species were identified and quantified every three hours for three days at three different atmospheric layers at the heart of Chiang-Mai, Bangkok and Hat-Yai from December 2006 to February 2007. A DRI Model 2001 Thermal/Optical Carbon Analyzer with the IMPROVE thermal/optical reflectance (TOR) protocol was used to quantify the organic carbon (OC) and elemental carbon (EC) contents in PM10. Diurnal and vertical variability was also carefully investigated. In general, OC and EC mass concentration showed the highest values at the monitoring period of 21.00-00.00 as consequences of human activities at night bazaar coupled with reduction of mixing layer, decreased wind speed and termination of photolysis at nighttime. Morning peaks of carbonaceous compounds were observed during the sampling period of 06:00-09:00, emphasizing the main contribution of traffic emission in the three cities. The estimation of incremental lifetime particulate matter exposure (ILPE) raises concern of high risk of carbonaceous accumulation over workers and residents living close to the observatory sites. The average values of incremental lifetime particulate matter exposure (ILPE) of total carbon at Baiyoke Suit Hotel and Baiyoke Sky Hotel are approximately ten times higher than those air samples collected at Prince of Songkla University Hat-Yai campus corpse incinerator and fish-can manufacturing factory but only slightly higher than those of rice straw burning in Songkla province. This indicates a high risk of developing lung cancer and other respiratory diseases across workers and residents living in high buildings located in Pratunam area. Using knowledge of carbonaceous fractions in PM10, one can estimate the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). Dachs-Eisenreich model highlights the crucial role of adsorption in gas

  5. Multiresidue analysis of multiclass pesticides and polyaromatic hydrocarbons in fatty fish by gas chromatography tandem mass spectrometry and evaluation of matrix effect.

    Science.gov (United States)

    Chatterjee, Niladri S; Utture, Sagar; Banerjee, Kaushik; Ahammed Shabeer, T P; Kamble, Narayan; Mathew, Suseela; Ashok Kumar, K

    2016-04-01

    This paper reports a selective and sensitive method for multiresidue determination of 119 chemical residues including pesticides and polyaromatic hydrocarbons (PAH) in high fatty fish matrix. The novel sample preparation method involved extraction of the target analytes from homogenized fish meat (5 g) in acetonitrile (15 mL, 1% acetic acid) after three-phase partitioning with hexane (2 mL) and the remaining aqueous layer. An aliquot (1.5 mL) of the acetonitrile layer was aspirated and subjected to two-stage dispersive solid phase extraction (dSPE) cleanup and the residues were finally estimated by gas chromatography mass spectrometry with selected reaction monitoring (GC-MS/MS). The co-eluted matrix components were identified on the basis of their accurate mass by GC with quadrupole time of flight MS. Addition of hexane during extraction and optimized dSPE cleanup significantly minimized the matrix effects. Recoveries at 10, 25 and 50 μg/kg were within 60-120% with associated precision, RSD<11%.

  6. Optimization of two different dispersive liquid-liquid microextraction methods followed by gas chromatography-mass spectrometry determination for polycyclic aromatic hydrocarbons (PAHs) analysis in water.

    Science.gov (United States)

    Tseng, Wan-Chi; Chen, Pai-Shan; Huang, Shang-Da

    2014-03-01

    Novel sample preparation methods termed "up-and-down shaker-assisted dispersive liquid-liquid microextraction (UDSA-DLLME)" and "water with low concentration of surfactant in dispersed solvent-assisted emulsion dispersive liquid-liquid microextraction (WLSEME)" coupled with gas chromatography-mass spectrometry (GC-MS) have been developed for the analysis of 11 polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. For UDSA-DLLME, an up-and-down shaker-assisted emulsification was employed. Extraction was complete in 3min. Only 14 μL of 1-heptanol was required, without a dispersive solvent. Under the optimum conditions, the linear range was 0.08-100 µg L(-1), and the LODs were in the range 0.022-0.060 µg L(-1). The enrichment factors (EFs) ranged from 392 to 766. Relative recoveries were between 84% and 113% for river, lake, and field water. In WLSEME, 9 μL of 1-nonanol as extraction solvent and 240 μL of 1 mg L(-1) Triton X-100 as surfactant were mixed in a microsyringe to form a cloudy emulsified solution, which was then injected into the samples. Compared with other surfactant-assisted emulsion methods, WLSEME uses much less surfactant. The linear range was 0.08-100 µg L(-1), and the LODs were 0.022-0.13 µg L(-1). The EFs ranged from 388 to 649. The relative recoveries were 86-114% for all three water specimens.

  7. Cork as a new (green) coating for solid-phase microextraction: determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Dias, Adriana Neves; Simão, Vanessa; Merib, Josias; Carasek, Eduardo

    2013-04-15

    A new fiber for solid-phase microextraction (SPME) was prepared employing cork as a coating. The morphology and composition of the cork fiber was evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The proposed fiber was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples by gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS). A central composite design was used for optimization of the variables involved in the extraction of PAHs from water samples. The optimal extraction conditions were extraction time and temperature of 60 min and 80°C, respectively. The detection and quantification limits were 0.03 and 0.1 μg L(-1), respectively. The recovery values were between 70.2 and 103.2% and the RSD was ≤15.7 (n=3). The linear range was 0.1-10 μg L(-1) with r≥0.96 and the fiber-to-fiber reproducibility showed RSD≤18.6% (n=5). The efficiency of the cork fiber was compared with commercially available fibers and good results were achieved, demonstrating the applicability and great potential of cork as a coating for SPME.

  8. QuEChERS Method Followed by Solid Phase Extraction Method for Gas Chromatographic-Mass Spectrometric Determination of Polycyclic Aromatic Hydrocarbons in Fish

    Directory of Open Access Journals (Sweden)

    Mona Khorshid

    2015-01-01

    Full Text Available A gas chromatography equipped with mass spectrometer (GCMS method was developed and validated for determination of 16 polycyclic aromatic hydrocarbons (PAHs in fish using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS method for extraction and solid phase extraction for sample cleanup to remove most of the coextract combined with GCMS for determination of low concentration of selected group of PAHs in homogenized fish samples. PAHs were separated on a GCMS with HP-5ms Ultra Inert GC Column (30 m, 0.25 mm, and 0.25 µm. Mean recovery ranged from 56 to 115%. The extraction efficiency was consistent over the entire range where indeno(1,2,3-cdpyrene and benzo(g,h,iperylene showed recovery (65, 69%, respectively, at 2 µg/kg. No significant dispersion of results was observed for the other remaining PAHs and recovery did not differ substantially, and at the lowest and the highest concentrations mean recovery and RSD% showed that most of PAHs were between 70% and 120% with RSD less than 10%. The measurement uncertainty is expressed as expanded uncertainty and in terms of relative standard deviation (at 95% confidence level is ±12%. This method is suitable for laboratories engaged daily in routine analysis of a large number of samples.

  9. Internal standards for use in the comprehensive analysis of polychlorinated aromatic hydrocarbons using gas chromatography combined with multiphoton ionization mass spectrometry.

    Science.gov (United States)

    Li, Adan; Imasaka, Totaro

    2016-10-28

    To decrease health-risks to humans, non-toxic compounds were evaluated for use as internal standards for calibrating data obtained by gas chromatography/multiphoton ionization mass spectrometry (GC-MPI-MS) using an ultraviolet femtosecond laser as the ionization source. The retention time in the mass chromatogram was calibrated using a retention index, in which a series of n-alkanes was employed as internal standards for evaluating the retention times for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). To compensate for changes in signal intensity in MPI-MS, the dependence of signal intensity on the laser pulse energy was investigated for the dioxin-like compounds, in addition to five non-toxic aromatic hydrocarbons, that were used as internal standards. Based on their similar behavior,the non-toxic PCDD/PCDF, its (13)C-isotope, and pentachlorobenzene behave similarly, we conclude that they can be used for calibrating the signal intensities in MPI-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Quantification of 13 priority polycyclic aromatic hydrocarbons in human urine by headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry.

    Science.gov (United States)

    Campo, Laura; Mercadante, Rosa; Rossella, Federica; Fustinoni, Silvia

    2009-01-12

    Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants in both living and working environments. The aim of this study was the development of a headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry (HS-SPME/GC-IDMS) method for the simultaneous quantification of 13 PAHs in urine samples. Different parameters affecting PAHs extraction by HS-SPME were considered and optimized: type/thickness of fiber coatings, extraction temperature/time, desorption temperature/time, ionic strength and sample agitation. The stability of spiked PAHs solutions and of real urine samples stored up to 90 days in containers of different materials was evaluated. In the optimized method, analytes were absorbed for 60min at 80 degrees C in the sample headspace with a 100mum polydimethylsiloxane fiber. The method is very specific, with linear range from the limit of quantification to 8.67 x 10(3)ngL(-1), a within-run precision of <20% and a between-run precision of <20% for 2-, 3- and 4-ring compounds and of <30% for 5-ring compounds, trueness within 20% of the spiked concentration, and limit of quantification in the 2.28-2.28 x 10(1)ngL(-1) range. An application of the proposed method using 15 urine samples from subjects exposed to PAHs at different environmental levels is shown.

  11. Quantification of 13 priority polycyclic aromatic hydrocarbons in human urine by headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Campo, Laura [Department of Occupational and Environmental Health, University of Milan and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan (Italy)], E-mail: laura.campo@unimi.it; Mercadante, Rosa; Rossella, Federica; Fustinoni, Silvia [Department of Occupational and Environmental Health, University of Milan and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan (Italy)

    2009-01-12

    Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants in both living and working environments. The aim of this study was the development of a headspace solid-phase microextraction gas chromatography-isotope dilution mass spectrometry (HS-SPME/GC-IDMS) method for the simultaneous quantification of 13 PAHs in urine samples. Different parameters affecting PAHs extraction by HS-SPME were considered and optimized: type/thickness of fiber coatings, extraction temperature/time, desorption temperature/time, ionic strength and sample agitation. The stability of spiked PAHs solutions and of real urine samples stored up to 90 days in containers of different materials was evaluated. In the optimized method, analytes were absorbed for 60 min at 80 deg. C in the sample headspace with a 100 {mu}m polydimethylsiloxane fiber. The method is very specific, with linear range from the limit of quantification to 8.67 x 10{sup 3} ng L{sup -1}, a within-run precision of <20% and a between-run precision of <20% for 2-, 3- and 4-ring compounds and of <30% for 5-ring compounds, trueness within 20% of the spiked concentration, and limit of quantification in the 2.28-2.28 x 10{sup 1} ng L{sup -1} range. An application of the proposed method using 15 urine samples from subjects exposed to PAHs at different environmental levels is shown.

  12. Time resolved studies of the addition reactions of silylenes and unsaturated hydrocarbons in the gas phase (an investigation of the strain energies of silirane and silirene rings)

    CERN Document Server

    Dormer, G

    1999-01-01

    This thesis reports the measurement of absolute rate constants for number of silylene addition reactions with unsaturated hydrocarbons. The reactions of SiH sub 2 , SiD sub 2 and Me sub 2 Si with alkene and alkynes were studied. The silylenes were formed, in situ, by the photolysis of an organosilicon precursor, and the rate constants obtained by the direct observation of the absorption decay of the silylene reactant. The reactions were studied in the gas phase and their temperature and pressure dependence investigated. The reaction of SiH sub 2 and 1,3-butadiene was investigated and found to be pressure dependent. The following Arrhenius equation was yielded at infinite pressure; log(k supinfinity/cm sup 3 molecule sup - sup 1 s sup - sup 1) = (-9.57 +- 0.05) + (3.22 +- 0.35) kJmol sup - sup 1 /RT ln 10. The reaction was found to proceed via a two-channel pathway, leading to the products vinylsilirane and silacyclopentane. RRKM modelling of the system was carried out and led to the calculation of the strain ...

  13. Simultaneous analysis of phthalates, adipate and polycyclic aromatic hydrocarbons in edible oils using isotope dilution-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Oh, Min-Seok; Lee, Seon-Hwa; Moon, Myeong Hee; Lee, Dong Soo; Park, Hyun-Mee

    2014-01-01

    A method for simultaneous determination of 12 priority phthalates, adipate and polycyclic aromatic hydrocarbons (PAHs) in edible oils by isotope dilution-gas chromatography-mass spectrometry (ID-GC-MS) was developed for fast, accurate and trace analysis. The extraction and clean-up procedures were optimised, and using stable isotope-labelled internal standards for each analyte, relative standard deviations (RSDs) of 0.92-10.6% and spiked sample recoveries of 80.6-97.8% were obtained. Limits of detection for PAHs were in the range of 0.15-0.77 µg/kg and those for phthalates were in the range of 4.6-10.0 µg/kg. The calibration curves exhibited good linearities with regression coefficients of R(2) ≥ 0.99. Twelve edible oils were examined to evaluate the efficiency of this method. Among the 12 analytes, dibutyl phthalates (DBP), diethylhexyl phthalates (DEHP), diethylhexyl adipate (DEHA), benzo[a]anthracene (B[a]A), chrysene (Chry) and benzo[b]fluoranthene (B[b]F) were detected in the range of 1.17-806 µg/kg.

  14. Evaluation of the contamination of spirits by polycyclic aromatic hydrocarbons using ultrasound-assisted emulsification microextraction coupled to gas chromatography-mass spectrometry.

    Science.gov (United States)

    Cacho, Juan Ignacio; Campillo, Natalia; Viñas, Pilar; Hernández-Córdoba, Manuel

    2016-01-01

    The concentration of twelve polycyclic aromatic hydrocarbons (PAHs), included in the list of priority pollutants, in different spirits has been obtained by means of a rapid and sensitive method based on gas chromatography and mass spectrometry (GC-MS). The environmentally friendly ultrasound-assisted emulsification microextraction (USAEME) technique allowed the easy and effective preconcentration of the PAHs from the sample matrices. Several parameters affecting the extraction efficiency, such as the nature and volume of the extractant solvent, and the addition of salt, as well as the sonication parameters were investigated and optimized. The absence of matrix effects under the optimized conditions allowed the sample quantification against aqueous standards. Detection limits ranged between 1.8 and 6.3 ng L(-1), depending on the compound. Different spirit samples were successfully analyzed using the proposed method, and contents of up to 0.9 μg L(-1) were found. Relative recoveries at fortified levels of 0.2 and 1 μg L(-1) were in the range 84-118%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Determination of 16 polycyclic aromatic hydrocarbons in seawater using molecularly imprinted solid-phase extraction coupled with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Song, Xingliang; Li, Jinhua; Xu, Shoufang; Ying, Rongjian; Ma, Jiping; Liao, Chunyang; Liu, Dongyan; Yu, Junbao; Chen, Lingxin

    2012-09-15

    A method of solid-phase extraction (SPE) using molecularly imprinted polymers (MIPs) as adsorbent coupled with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of 16 types of polycyclic aromatic hydrocarbons (PAHs) in seawater samples. The MIPs were prepared through non-covalent polymerization by using the 16 PAHs mixture as a template based on sol-gel surface imprinting. Compared with the non-imprinted polymers (NIPs), the MIPs exhibited excellent affinity towards 16 PAHs with binding capacity of 111.0-195.0 μg g(-1), and imprinting factor of 1.50-3.12. The significant binding specificity towards PAHs even in the presence of environmental parameters such as dissolved organic matter and various metal ions, suggested that this new imprinting material was capable of removing 93.2% PAHs in natural seawater. High sensitivity was attained, with the low limits of detection for 16 PAHs in natural seawater ranging from 5.2-12.6 ng L(-1). The application of MIPs with high affinity and excellent stereo-selectivity toward PAHs in SPE might offer a more attractive alternative to conventional sorbents for extraction and abatement of PAH-contaminated seawater.

  16. Gas chromatography-mass spectrometric determination of polycyclic aromatic hydrocarbons in five species of fish from three sites in the Arabian Gulf.

    Science.gov (United States)

    Al-Saleh, Iman; Al-Doush, Inaam

    2002-06-01

    A gas chromatography-mass spectrmetroic (GC-MS) method was developed to measure six polycyclic aromatic hydrocarbons (PAHs) in 54 fish samples. Five fish species highly consumed by the local population (shrimps, Emperors, Rabbitfish, Doublebar Bream and Greasy Grouper) were selected from three different sites on the Gulf coast of Saudi Arabia where agricultural, municipal and petroleum industry activities take place. Variations in PAH levels among the three sites were not significant. Total concentrations of PAHs benzo(a)anthracene, chrysene, and benzo(b)fluoranthene ranged from non-detectable to 44.9 microg kg(-1). In this study, concentrations of benzo(a)anthracene, chrysene, benzo(b)fluoranthene and total PAHs greater than the acceptable tolerance limit (1 microg kg(-1)) were found in 68.5, 40.7, 51.9 and 83.3% of the fish samples, respectively. PAH contents in fish vary considerably with species; Doublebar bream contain the highest while shrimps contain the lowest. This pilot study clearly shows that the consumption of fish could be a source of exposure of the local population to PAHs. Since there is a consensus on the substantial contribution of PAHs to cancer in humans, it would be interesting to conduct further research in order to determine the magnitude of the problem along other coastal regions of Saudi Arabia.

  17. Triacontyl modified silica gel as a sorbent for the preconcentration of polycyclic aromatic hydrocarbons in aqueous samples prior to gas chromatographic-mass spectrometry determination

    Institute of Scientific and Technical Information of China (English)

    Yan

    2010-01-01

    Triacontyl modified silica gel as a sorbent coupled with gas chromatography-mass spectrometry (GC-MS) was developed to determine EPA prior 16 polycyclic aromatic hydrocarbons (PAHs) in water samples. Various parameters of solid-phase extraction such as organic modifier solvent, eluent, sample flow rate and volume were optimized. The developed method was found to yield a linear calibration curve in the concentration range of 0.05-8 μg/L with respect to naphthalene, acenaphthylene, acenaphthene and 0.01-8μg/L for dibenz[a,h]anthracene and 0.05-14 μg/L for fluorene, phenanthrene, anthracene and 0.01-14 μg/L for the rest of analytes. Furthermore, the good accuracy and repeatability of the method made sure the requirements for achieving reliable analysis of PAHs in the environmental water samples, and the recoveries of optimal method were in the range of 80-120% except to higher volatility PAHs. C30-bonded silica was proved to be an efficient sorbent for extraction of high molecular weight PAHs.

  18. Agarose film liquid phase microextraction combined with gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in water.

    Science.gov (United States)

    Sanagi, Mohd Marsin; Loh, Saw Hong; Wan Ibrahim, Wan Aini; Hasan, Mohamed Noor

    2012-11-01

    Agarose film liquid phase microextraction (AF-LPME) procedure for the extraction and preconcentration of polycyclic aromatic hydrocarbons (PAHs) in water has been investigated. Agarose film was used for the first time as an interface between donor and acceptor phases in liquid phase microextraction which allowed for selective extraction of the analytes prior to gas chromatography-mass spectrometry. Using 1-octanol as acceptor phase, high enrichment factors in the range of 57-106 for the targeted analytes (fluorene, phenanthrene, fluoranthene and pyrene) were achieved. Under the optimum extraction conditions, the method showed good linearity in the range of 0.1-200 μgL(-1), good correlation coefficients in the range of 0.9963-0.9999, acceptable reproducibility (RSD 6.1-9.2%, n=3), low limits of detection (0.01-0.04 μgL(-1)) and satisfactory relative recoveries (92.9-104.7%). As the AF-LPME device was non-expensive, reuse or recycle of the film was not required, thus eliminating the possibility of analytes carry-over between runs. The AF-LPME technique is environment-friendly and compatible with the green chemistry concept as agarose is biodegradable polysaccharide extracted from seaweed and the procedure requires small volume of organic solvent and generates little waste. The validated method was successfully applied to the analysis of the four analytes in river water samples.

  19. Advances in Hydrogen, Carbon Dioxide, and Hydrocarbon Gas Sensor Technology Using GaN and ZnO-Based Devices

    Directory of Open Access Journals (Sweden)

    Jenshan Lin

    2009-06-01

    Full Text Available In this paper, we review our recent results in developing gas sensors for hydrogen using various device structures, including ZnO nanowires and GaN High Electron Mobility Transistors (HEMTs. ZnO nanowires are particularly interesting because they have a large surface area to volume ratio, which will improve sensitivity, and because they operate at low current levels, will have low power requirements in a sensor module. GaN-based devices offer the advantage of the HEMT structure, high temperature operation, and simple integration with existing fabrication technology and sensing systems. Improvements in sensitivity, recoverability, and reliability are presented. Also reported are demonstrations of detection of other gases, including CO2 and C2H4 using functionalized GaN HEMTs. This is critical for the development of lab-on-a-chip type systems and can provide a significant advance towards a market-ready sensor application.

  20. Advances in Hydrogen, Carbon Dioxide, and Hydrocarbon Gas Sensor Technology Using GaN and ZnO-Based Devices.

    Science.gov (United States)

    Anderson, Travis; Ren, Fan; Pearton, Stephen; Kang, Byoung Sam; Wang, Hung-Ta; Chang, Chih-Yang; Lin, Jenshan

    2009-01-01

    In this paper, we review our recent results in developing gas sensors for hydrogen using various device structures, including ZnO nanowires and GaN High Electron Mobility Transistors (HEMTs). ZnO nanowires are particularly interesting because they have a large surface area to volume ratio, which will improve sensitivity, and because they operate at low current levels, will have low power requirements in a sensor module. GaN-based devices offer the advantage of the HEMT structure, high temperature operation, and simple integration with existing fabrication technology and sensing systems. Improvements in sensitivity, recoverability, and reliability are presented. Also reported are demonstrations of detection of other gases, including CO(2) and C(2)H(4) using functionalized GaN HEMTs. This is critical for the development of lab-on-a-chip type systems and can provide a significant advance towards a market-ready sensor application.

  1. THERMOCHEMISTRY OF HYDROCARBON RADICALS

    Energy Technology Data Exchange (ETDEWEB)

    Kent M. Ervin, Principal Investigator

    2004-08-17

    Gas phase negative ion chemistry methods are employed to determine enthalpies of formation of hydrocarbon radicals that are important in combustion processes and to investigate the dynamics of ion-molecule reactions. Using guided ion beam tandem mass spectrometry, we measure collisional threshold energies of endoergic proton transfer and hydrogen atom transfer reactions of hydrocarbon molecules with negative reagent ions. The measured reaction threshold energies for proton transfer yield the relative gas phase acidities. In an alternative methodology, competitive collision-induced dissociation of proton-bound ion-molecule complexes provides accurate gas phase acidities relative to a reference acid. Combined with the electron affinity of the R {center_dot} radical, the gas phase acidity yields the RH bond dissociation energy of the corresponding neutral molecule, or equivalently the enthalpy of formation of the R{center_dot} organic radical, using equation: D(R-H) = {Delta}{sub acid}H(RH) + EA(R) - IE(H). The threshold energy for hydrogen abstraction from a hydrocarbon molecule yields its hydrogen atom affinity relative to the reagent anion, providing the RH bond dissociation energy directly. Electronic structure calculations are used to evaluate the possibility of potential energy barriers or dynamical constrictions along the reaction path, and as input for RRKM and phase space theory calculations. In newer experiments, we have measured the product velocity distributions to obtain additional information on the energetics and dynamics of the reactions.

  2. Shallow rainwater lenses in deltaic areas with saline seepage

    Directory of Open Access Journals (Sweden)

    P. G. B. de Louw

    2011-08-01

    Full Text Available In deltaic areas with saline seepage, fresh water availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and size. Our findings are based on different types of field measurements and detailed numerical groundwater models applied in the south-western delta of The Netherlands. By combining the applied techniques we could extrapolate in situ measurements at point scale (groundwater sampling, TEC (temperature and electrical soil conductivity-probe measurements, electrical cone penetration tests (ECPT to a field scale (continuous vertical electrical soundings (CVES, electromagnetic survey with EM31, and even to a regional scale using helicopter-borne electromagnetic measurements (HEM. The measurements show a gradual S-shaped mixing zone between infiltrating fresh rainwater and upward flowing saline groundwater. The mixing zone is best characterized by the depth of the centre of the mixing zone Dmix, where the salinity is half that of seepage water, and the bottom of the mixing zone Bmix, with a salinity equal to that of the seepage water (Cl-conc. 10 to 16 g l−1. Dmix manifests at very shallow depth in the confining top layer, on average at 1.7 m below ground level (b.g.l., while Bmix lies about 2.5 m b.g.l. Head-driven forced convection is the main mechanism of rainwater lens formation in the saline seepage areas rather than free convection due to density differences. Our model results show that the sequence of alternating vertical flow directions in the confining layer caused by head gradients determines the position of the mixing zone (Dmix and Bmix and that these flow directions are controlled by seepage flux, recharge and drainage depth.

  3. Efficacy of head space solid-phase microextraction coupled to gas chromatography-mass spectrometry method for determination of the trace extracellular hydrocarbons of cyanobacteria.

    Science.gov (United States)

    Guan, Wenna; Zhu, Tao; Wang, Yuejie; Zhang, Zhongyi; Jin, Zhao; Wang, Cong; Bai, Fali

    2016-09-01

    Hydrocarbons are widespread in cyanobacteria, and the biochemical synthetic pathways were recently identified. Intracellular fatty alka(e)nes of cyanobacteria have been detected by liquid-liquid extraction (LLE) coupled to gas chromatography-mass spectrometry (GC/MS). However, whether fatty alka(e)nes can be released to cyanobacterial culture media remains to be clarified. This work develops a sensitive method for analyzing the trace level of extracellular hydrocarbons in cyanobacterial culture media by head space solid-phase microextraction (HS-SPME) coupled to GC/MS. Headspace (HS) extraction mode using polydimethylsiloxane fiber to extract for 30min at 50°C was employed as the optimal extraction conditions. Five cyanobacterial fatty alka(e)nes analogs including pentadecene (C15:1), pentadecane (C15:0), heptadecene (C17:1), heptadecane (C17:0), nonadecane (C19:0) were analyzed, and the data obtained from HS-SPME-GC/MS method were quantified using internal standard peak area comparisons. Limits of detection (LOD), limits of quantitation (LOQ), linear dynamic range, precisions (RSD) and recovery for the analysis of extracellular fatty alka(e)nes of cyanobacteria by HS-SPME-GC/MS were evaluated. The LODs limits of detection (S/N = 3) varied from 10 to 21 ng L-1. The correlation coefficients (r) of the calibration curves ranged from 0.9873 to 0.9977 with a linearity from 0.1 to 50 μg L-1. The RSD values were ranging from 7.8 to 14.0% and from 4.0 to 8.8% at 1.0 μg L-1 and 10.0 μg L-1 standard solutions, respectively. Comparative analysis of extracellular fatty alka(e)nes in the culture media of model cyanobacteria Synechocystis sp. PCC 6803 demonstrated that sensitivity of HS-SPME-GC/MS method was significantly higher than LLE method. Finally, we found that heptadecane can be released into the culture media of Synechocystis sp. PCC 6803 at the later growth period.

  4. Effect of upward seepage on bedload transport rate

    Directory of Open Access Journals (Sweden)

    Xiao-xie LIU

    2014-04-01

    Full Text Available The paper presents an investigation of injection effects on the bedload transport rate. According to dimensional analysis, two dimensionless groups, an Einstein’s parameter group and a modified densimetric Froude number group, were chosen to examine how injection affects the bedload transport rate. Experimental studies were conducted in an open-channel flume with an upward seepage zone. The sediment particles used for the test were 0.9 mm in diameter. The experimental results show that an increase in the injection velocity causes a reduction in the shear velocity excess, which is defined as the difference between the shear and critical shear velocities, leading to a reduction in the bedload transport rate. The equation for predicting the bedload transport rate in the presence of upward seepage was derived empirically. The proposed prediction method is suitable for engineering practice, since it only requires the undisturbed flow condition, properties of sediment particles, and the injection velocity.

  5. Numerical simulations of seepage flow in rough single rock fractures

    Directory of Open Access Journals (Sweden)

    Qingang Zhang

    2015-09-01

    Full Text Available To investigate the relationship between the structural characteristics and seepage flow behavior of rough single rock fractures, a set of single fracture physical models were produced using the Weierstrass–Mandelbrot functions to test the seepage flow performance. Six single fractures, with various surface roughnesses characterized by fractal dimensions, were built using COMSOL multiphysics software. The fluid flow behavior through the rough fractures and the influences of the rough surfaces on the fluid flow behavior was then monitored. The numerical simulation indicates that there is a linear relationship between the average flow velocity over the entire flow path and the fractal dimension of the rough surface. It is shown that there is good a agreement between the numerical results and the experimental data in terms of the properties of the fluid flowing through the rough single rock fractures.

  6. Seepage and seepage gradients in an homogeneous, isotropic aquifer with drains as a function of soil properties and flow region geometry

    Science.gov (United States)

    Seepage and seepage gradients are important parameters in soil erosion processes and water quality problems on agricultural land. Traditionally, surface overland flow is viewed as one of the major soil erosive agents on those areas. In recent years, the role of the subsurface flow regime is increasi...

  7. Syngas Upgrading to Hydrocarbon Fuels Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Talmadge, M.; Biddy, M.; Dutta, A.; Jones, S.; Meyer, A.

    2013-03-01

    This technology pathway case investigates the upgrading of woody biomass derived synthesis gas (syngas) to hydrocarbon biofuels. While this specific discussion focuses on the conversion of syngas via a methanol intermediate to hydrocarbon blendstocks, there are a number of alternative conversion routes for production of hydrocarbons through a wide array of intermediates from syngas. Future work will also consider the variations to this pathway to determine the most economically viable and lowest risk conversion route. Technical barriers and key research needs have been identified that should be pursued for the syngas-to-hydrocarbon pathway to be competitive with petroleum-derived gasoline-, diesel- and jet-range hydrocarbon blendstocks.

  8. Development of gas chromatography-flame ionization detection system with a single column and liquid nitrogen-free for measuring atmospheric C2-C12 hydrocarbons.

    Science.gov (United States)

    Liu, Chengtang; Mu, Yujing; Zhang, Chenglong; Zhang, Zhibo; Zhang, Yuanyuan; Liu, Junfeng; Sheng, Jiujiang; Quan, Jiannong

    2016-01-04

    A liquid nitrogen-free GC-FID system equipped with a single column has been developed for measuring atmospheric C2-C12 hydrocarbons. The system is consisted of a cooling unit, a sampling unit and a separation unit. The cooling unit is used to meet the temperature needs of the sampling unit and the separation unit. The sampling unit includes a dehydration tube and an enrichment tube. No breakthrough of the hydrocarbons was detected when the temperature of the enrichment tube was kept at -90 °C and sampling volume was 400 mL. The separation unit is a small round oven attached on the cooling column. A single capillary column (OV-1, 30 m × 0.32 mm I.D.) was used to separate the hydrocarbons. An optimal program temperature (-60 ∼ 170 °C) of the oven was achieved to efficiently separate C2-C12 hydrocarbons. There were good linear correlations (R(2)=0.993-0.999) between the signals of the hydrocarbons and the enrichment amount of hydrocarbons, and the relative standard deviation (RSD) was less than 5%, and the method detection limits (MDLs) for the hydrocarbons were in the range of 0.02-0.10 ppbv for sampling volume of 400 mL. Field measurements were also conducted and more than 50 hydrocarbons from C2 to C12 were detected in Beijing city.

  9. Shallow bedrock limits groundwater seepage-based headwater climate refugia

    Science.gov (United States)

    Briggs, Martin; Lane, John; Snyder, Craig D.; White, Eric A.; Johnson, Zachary; Nelms, David L.; Hitt, Nathaniel P.

    2017-01-01

    Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater streams, however, may also be sensitive to seasonal and long-term air temperature dynamics. Depth to bedrock can directly influence shallow aquifer flow and thermal sensitivity, but is typically ill-defined along the stream corridor in steep mountain catchments. We employ rapid, cost-effective passive seismic measurements to evaluate the variable thickness of the shallow colluvial and alluvial aquifer sediments along a headwater stream supporting cold water-dependent brook trout (Salvelinus fontinalis) in Shenandoah National Park, VA, USA. Using a mean depth to bedrock of 2.6 m, numerical models predicted strong sensitivity of shallow aquifer temperature to the downward propagation of surface heat. The annual temperature dynamics (annual signal amplitude attenuation and phase shift) of potential seepage sourced from the shallow modeled aquifer were compared to several years of paired observed stream and air temperature records. Annual stream water temperature patterns were found to lag local air temperature by ∼8–19 d along the stream corridor, indicating that thermal exchange between the stream and shallow groundwater is spatially variable. Locations with greater annual signal phase lag were also associated with locally increased amplitude attenuation, further suggestion of year-round buffering of channel water temperature by groundwater seepage. Numerical models of shallow groundwater temperature that incorporate regional expected climate warming trends indicate that the summer cooling capacity of this groundwater seepage will be reduced over time, and lower-elevation stream sections may no longer serve as larger

  10. Authigenic carbonates from an active cold seep of the northern South China Sea: New insights into fluid sources and past seepage activity

    Science.gov (United States)

    Feng, Dong; Chen, Duofu

    2015-12-01

    Site F (also named Formosa ridge) represents the most vigorous cold seep on the northern South China Sea continental slope. In order to constrain the fluid sources and intensities of seepage, we investigated the petrography, mineralogy, stable carbon and oxygen isotopic compositions, element geochemistry and radiocarbon dating of authigenic carbonate rocks retrieved from the seafloor. Carbonate rocks mainly occurred as crusts, nodules, and nodular masses incorporated in carbonate breccias. The carbonates were comprised mainly of high-Mg calcite and aragonite. The δ13C of authigenic carbonate varied from -55.3‰ to -34.3‰ (mean: -48.5‰; n=47) vs. V-PDB, suggesting biogenic methane is the dominant carbon source fuelling the system. The δ18OCarbonate values were from +3.6‰ to +4.8‰ (mean: +3.9‰; n=47). The observed 18O-enrichement in relation to calculated equilibrium values in the carbonates probably reflects dissolution of gas hydrates. Combination of seafloor observations and the obtained AMS 14C ages suggest that (1) initiation of methane seepage from at least 10.6 ka ago; (2) environmental conditions may have been favorable for enhanced fluid seepage around 6 ka BP and (3) relatively low intensity of seepage from 2 ka BP till today.

  11. Coupling Seepage and Radionuclide Transport in and Around Emplacement Drifts at Yucca Mountain

    Science.gov (United States)

    Zhang, G.; Spycher, N.; Sonnenthal, E.; Steefel, C.

    2007-12-01

    The proposed nuclear waste repository of the United States is located at Yucca Mountain, Nevada. Waste packages will be placed in deep (~350 m) underground drifts in volcanic tuff. Seepage may potentially occur at the repository drifts when the drifts get rewetted after a dryout period. The potential seepage water will be quickly evaporated or boiled to near dryness as long as it falls on the top of the hot waste package leading to formation of brine, precipitation of salts and volatilization of gases. These processes may potentially impact the long-term safety of waste packages in the drift. The objectives of this study are to: (1) develop a quantitative model of coupled thermal, hydrological, and chemical (THC) processes potentially leading to brine formation, salt precipitation and gas volatilization on top of waste packages and/or a drip shield and (2) dynamically integrate such a model into the larger-scale models of processes within and around waste emplacement drifts, as well as into the smaller-scale waste-package corrosion models. Process models were implemented into an existing reactive transport numerical simulator, TOUGHREACT, to allow modeling of (1) evaporative concentration to very high ionic strength (up to 40 molal), (2) boiling point elevation due to dissolved salts, (3) boiling/evaporation to dryness, and (4) salt deliquescence. An integrated near-field and in-drift THC simulation was run using a vertical 2-D grid extending from near the ground surface to the groundwater table, and covering a width equal to half the design drift spacing of 81 m. The integrated model was then used to simulate a discrete dripping event within the drift. The model considered the release of radionuclides into seepage water as this water contacts the waste package and flows through the invert. The precipitation of uranophane and Np-uranophane was also considered. These minerals form in the invert from the neutralization of mildly acidic seepage water by clay minerals

  12. Monitoring technique for seepage line of tailings dam

    Institute of Scientific and Technical Information of China (English)

    李夕兵; 蒋卫东

    2003-01-01

    An automatic monitoring technique of the seepage line, including the monitoring design, the automatic monitoring system and the backfill technique of the measuring probe of pore-water pressure, was used in a tailings dam, and a shallow refractive seismic method was investigated for obtaining the seepage line of those areas outside the monitoring zone. The results show that the automatic monitoring has the error within ± 3 % relative to piezometric tube method and improves monitoring efficiency greatly, and the shallow refractive seismic method has the error within ± 10% but expands the area of monitoring. Both of them can be used for a daily measurement in monitoring the seepage line. The result of the automatic monitoring also shows that not only the design of the survey line and the backfill technique of the measuring probe of pore-water pressure are reasonable and economic but also the reliability and safety of the automatic monitoring system are better. Testing result by the shallow refractive seismic method in tailings reveals that the energy excited by hammering iron sheet-pole is strong enough and safe, and that the character of anti-jamming by the detectors with long tailcone is better.

  13. Analytically computed rates of seepage flow into drains and cavities

    Science.gov (United States)

    Fujii, N.; Kacimov, A. R.

    1998-04-01

    The known formulae of Freeze and Cherry, Polubarinova-Kochina, Vedernikov for flow rate during 2-D seepage into horizontal drains and axisymmetric flow into cavities are examined and generalized. The case of an empty drain under ponded soil surface is studied and existence of drain depth providing minimal seepage rate is presented. The depth is found exhibiting maximal difference in rate between a filled and an empty drain. 3-D flow to an empty semi-spherical cavity on an impervious bottom is analysed and the difference in rate as compared with a completely filled cavity is established. Rate values for slot drains in a two-layer aquifer are inverted using the Schulgasser theorem from the Polubarinova-Kochina expressions for corresponding flow rates under a dam. Flow to a point sink modelling a semi-circular drain in a layered aquifer is treated by the Fourier transform method. For unsaturated flow the catchment area of a single drain is established in terms of the quasi-linear model assuming the isobaric boundary condition along the drain contour. Optimal shape design problems for irrigation cavities are addressed in the class of arbitrary contours with seepage rate as a criterion and cavity cross-sectional area as an isoperimetric restriction.

  14. Seepage assessment of Hattian Bala landslide dam using hydrological data

    Energy Technology Data Exchange (ETDEWEB)

    Niazi, F.S. [Georgia Inst.of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Akram, T.; Haider, S. [National Univ. of Sciences and Technology, Islamabad (Pakistan). National Inst.of Transportation

    2009-07-01

    In 2005, a M7.6 earthquake in Pakistan triggered a landslide that blocked two tributaries of the Jhelum River at their confluence, near Muzzafarabad, Azad Kashmir, creating two lakes. Flooding upstream of this natural dam can cause substantial downstream damage in case of failure. This paper presented the results of a study aimed at evaluating the inflow of water into the dam body through seepage from the larger lake by utilizing hydrological data. The objectives of the study were to assess the possibility of seepage from Karli Lake by comparing daily upstream inflows from both channels with the downstream discharges; estimate the loss of water into the dam body from Karli Lake by comparing the actual daily increase in volume in the Karli Lake with the daily upstream inflow volume of Karli channel; and estimate the seepage volume by combining the upstream inflow volume and comparing it with the downstream discharge volume. Although the desired results could not be obtained due to inadequate data, a practical method was developed for use in similar cases. 10 refs., 1 tab., 13 figs.

  15. Kinetic simulating experiment on the secondary hydrocarbon generation of kerogen

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The kinetic parameters of generation have been obtained for different hydrocarbon classes, including methane, C2-C5 gas hydrocarbons, C6-C13 light hydrocarbons and C13+ heavy hydrocarbons, and vitrinite reflectance (Ro) by the kinetic simulating experiment of kerogen cracking. Then, combined with the detailed geology of Sichuan Basin, the effective gas-generating intensity of the Lower Cambrian source rock is approximately estimated by applying these parameters.

  16. Highly sensitive determination of polycyclic aromatic hydrocarbons in ambient air dust by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction.

    Science.gov (United States)

    Krupadam, Reddithota J; Bhagat, Bhagyashree; Khan, Muntazir S

    2010-08-01

    A method based on solid--phase extraction with a molecularly imprinted polymer (MIP) has been developed to determine five probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry (GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phase extraction (SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L(-1) (r = 0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials--powdered activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD)--and it was shown that the extraction capacity of the MIP was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L(-1) for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic PAHs in air dust of industrial zones and satisfactory results were obtained.

  17. 3-D CFD Simulation and Validation of Oxygen-Rich Hydrocarbon Combustion in a Gas-Centered Swirl Coaxial Injector using a Flamelet-Based Approach

    Science.gov (United States)

    Richardson, Brian; Kenny, Jeremy

    2015-01-01

    Injector design is a critical part of the development of a rocket Thrust Chamber Assembly (TCA). Proper detailed injector design can maximize propulsion efficiency while minimizing the potential for failures in the combustion chamber. Traditional design and analysis methods for hydrocarbon-fuel injector elements are based heavily on empirical data and models developed from heritage hardware tests. Using this limited set of data produces challenges when trying to design a new propulsion system where the operating conditions may greatly differ from heritage applications. Time-accurate, Three-Dimensional (3-D) Computational Fluid Dynamics (CFD) modeling of combusting flows inside of injectors has long been a goal of the fluid analysis group at Marshall Space Flight Center (MSFC) and the larger CFD modeling community. CFD simulation can provide insight into the design and function of an injector that cannot be obtained easily through testing or empirical comparisons to existing hardware. However, the traditional finite-rate chemistry modeling approach utilized to simulate combusting flows for complex fuels, such as Rocket Propellant-2 (RP-2), is prohibitively expensive and time consuming even with a large amount of computational resources. MSFC has been working, in partnership with Streamline Numerics, Inc., to develop a computationally efficient, flamelet-based approach for modeling complex combusting flow applications. In this work, a flamelet modeling approach is used to simulate time-accurate, 3-D, combusting flow inside a single Gas Centered Swirl Coaxial (GCSC) injector using the flow solver, Loci-STREAM. CFD simulations were performed for several different injector geometries. Results of the CFD analysis helped guide the design of the injector from an initial concept to a tested prototype. The results of the CFD analysis are compared to data gathered from several hot-fire, single element injector tests performed in the Air Force Research Lab EC-1 test facility

  18. Implementation of comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for the simultaneous determination of halogenated contaminants and polycyclic aromatic hydrocarbons in fish

    Energy Technology Data Exchange (ETDEWEB)

    Kalachova, Kamila; Pulkrabova, Jana; Cajka, Tomas; Drabova, Lucie; Hajslova, Jana [Institute of Chemical Technology, Prague (Czech Republic). Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology

    2012-07-15

    In the presented study, comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS) was shown to be a powerful tool for the simultaneous determination of various groups of contaminants including 18 polychlorinated biphenyls (PCBs), seven polybrominated diphenyl ethers (PBDEs), and 16 polycyclic aromatic hydrocarbons (PAHs). Since different groups of analytes (traditionally analyzed separately) were included into one instrumental method, significant time savings were achieved. Following the development of an integrated sample preparation procedure for an effective and rapid isolation of several groups of contaminants from fish tissue, the GC x GC-TOFMS instrumental method was optimized to obtain the best chromatographic resolution and low quantification limits (LOQs) of all target analytes in a complex mixture. Using large-volume programmable temperature vaporization, the following LOQs were achieved - PCBs, 0.01-0.25 {mu}g/kg; PBDEs, 0.025-5 {mu}g/kg; PAHs 0.025-0.5 {mu}g/kg. Furthermore, several capillary column combinations (BPX5, BPX50, and Rxi-17Sil-ms in the first dimension and BPX5, BPX50, Rt-LC35, and HT8 in the second dimension) were tested during the experiments, and the optimal separation of all target analytes even of critical groups of PAHs (group (a): benz[a]anthracene, cyclopenta[cd]pyrene and chrysene; group (b): benzo[b]fluoranthene, benzo[j]fluoranthene and benzo[k]fluoranthene; group (c): dibenz[ah]anthracene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene) was observed on BPX5 x BPX50 column setup. Moreover, since the determination of target analytes was performed using TOFMS detector, further identification of other non-target compounds in real life samples was also feasible. (orig.)

  19. Cork as a new (green) coating for solid-phase microextraction: Determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography–mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Adriana Neves; Simão, Vanessa; Merib, Josias [Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040900, SC (Brazil); Carasek, Eduardo, E-mail: eduardo.carasek@ufsc.br [Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis 88040900, SC (Brazil)

    2013-04-15

    Highlights: ► Cork as a new coating for solid-phase microextraction was proposed. ► Good results were achieved, demonstrating the applicability of the cork as coating for SPME. ► The efficiency of cork fiber was very similar to commercially available fibers. -- Abstract: A new fiber for solid-phase microextraction (SPME) was prepared employing cork as a coating. The morphology and composition of the cork fiber was evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The proposed fiber was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples by gas chromatography–selected ion monitoring–mass spectrometry (GC–SIM–MS). A central composite design was used for optimization of the variables involved in the extraction of PAHs from water samples. The optimal extraction conditions were extraction time and temperature of 60 min and 80 °C, respectively. The detection and quantification limits were 0.03 and 0.1 μg L{sup −1}, respectively. The recovery values were between 70.2 and 103.2% and the RSD was ≤15.7 (n = 3). The linear range was 0.1–10 μg L{sup −1} with r ≥ 0.96 and the fiber-to-fiber reproducibility showed RSD ≤ 18.6% (n = 5). The efficiency of the cork fiber was compared with commercially available fibers and good results were achieved, demonstrating the applicability and great potential of cork as a coating for SPME.

  20. Quantification of carcinogenic 4- to 6-ring polycyclic aromatic hydrocarbons in human urine by solid-phase microextraction gas chromatography-isotope dilution mass spectrometry.

    Science.gov (United States)

    Campo, Laura; Fustinoni, Silvia; Bertazzi, Pieralberto

    2011-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are pollutants found in living and working environments. The aim of this study was to develop a solid-phase microextraction (SPME) gas chromatography (GC)-isotope dilution mass spectrometry method for the quantification of 10 four- to six-ring PAHs in urine samples. Seven of the selected PAHs have been classified as carcinogenic. Under the final conditions, analytes were sampled with a 100-μm polydimethylsiloxane SPME fibre for 60 min at 80 °C and desorbed in the injection port of the GC at 270 °C. Fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene were separated using a highly arylene-modified phase capillary column and quantified by MS using eight deuterated PAHs as surrogate internal standards. Limits of quantification (LOQ) were in the 0.5- to 2.2-ng/L range. Validation showed linear dynamic ranges up to 340 ng/L, inter- and intra-run precisions <20%, and accuracies within 20% of spiked concentrations. Matrix effect evaluation and the use of control charts to monitor process performances showed that the isotope dilution approach allowed for the control of bias sources. Urinary PAHs were above or equal to LOQ, depending on different compounds, in 58-100% (min-max), 40-100% and 5-39% of samples from coke oven workers (n = 12), asphalt workers (n = 10) and individuals not occupationally exposed to PAHs (n = 18), respectively. Chrysene was the most abundant PAH determined with median levels of 62.6, 6.9 and <0.6 ng/L, respectively. These results show that the method is suitable for quantifying carcinogenic PAHs in specimens from individuals with different levels of PAH exposure.

  1. Purge-assisted headspace solid-phase microextraction combined with gas chromatography/mass spectrometry for the determination of trace nitrated polycyclic aromatic hydrocarbons in aqueous samples.

    Science.gov (United States)

    Hung, Cheng-Han; Ho, Hsin-Pin; Lin, Mei-Tzu; Chen, Chung-Yu; Shu, Youn-Yuen; Lee, Maw-Rong

    2012-11-23

    This study describes a new procedure, namely, purge-assisted headspace solid phase microextraction combined with gas chromatography/negative ion chemical ionization mass spectrometry (PA/HS-SPME-GC/NICI-MS), which is used to determine seven nitrated polycyclic aromatic hydrocarbons (NPAHs) in aqueous samples. High extraction efficiency was obtained with PA/HS-SPME with polydimethylsiloxane (PDMS) fiber coating. A programmable temperature vaporizing (PTV) inlet was used in the desorption process. Selected ion monitoring (SIM) was used for quantitative and qualitative purposes. The linear range of detection of the proposed method was 5-5000 pg/mL with coefficients of determination between 0.995 and 0.999. Limits of detection (LODs) for seven NPAHs were 0.01-0.06 pg/mL. The relative standard deviation was below 12.7% at a concentration of 50 pg/mL. Compared with headspace-solid phase microextraction (HS-SPME), the purge procedure enhanced the extraction efficiency for high boiling point analytes, such as 7-nitrobenz[a]anthracene (7-NBA) and 6-nitrochrysene (6-NC). The proposed method provides a sensitive method for NPAH analysis at the pg/mL level. The application of the proposed method for the determination of trace NPAHs in real samples was investigated by analyzing aqueous samples from rivers. The concentrations of NPAHs detected from the samples ranged from 5.2 to 7.5 pg/mL. This method was applied successfully in the analysis of trace NPAHs in river samples.

  2. Highly sensitive determination of polycyclic aromatic hydrocarbons in ambient air dust by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction

    Energy Technology Data Exchange (ETDEWEB)

    Krupadam, Reddithota J.; Bhagat, Bhagyashree; Khan, Muntazir S. [National Environmental Engineering Research Institute, Nagpur (India)

    2010-08-15

    A method based on solid-phase extraction with a molecularly imprinted polymer (MIP) has been developed to determine five probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry (GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phase extraction (SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L{sup -1} (r=0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials - powdered activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD) - and it was shown that the extraction capacity of the MIP was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L{sup -1} for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic PAHs in air dust of industrial zones and satisfactory results were obtained. (orig.)

  3. Gas chromatography for in situ analysis of a cometary nucleus. II. Analysis of permanent gases and light hydrocarbons with a carbon molecular sieve porous layer open tubular column.

    Science.gov (United States)

    Szopa, C; Sternberg, R; Coscia, D; Raulin, F; Vidal-Madjar, C

    2000-12-22

    Considering the severe constraints of space instrumentation, a great improvement for the in situ gas chromatographic (GC) determination of permanent and noble gases in a cometary nucleus is the use of a new carbon molecular sieve porous layer open tubular (PLOT) column called Carbobond. No exhaustive data dealing with this column being available, studies were carried out to entirely characterize its analytical performances, especially when used under the operating conditions of the cometary sampling and composition (COSAC) experiment of the European Space Agency (ESA) Rosetta space mission to be launched in 2003 for a rendezvous with comet 46 P/Wirtanen in 2011. The high efficiency and speed of analysis of this column at both atmospheric and vacuum outlet column pressure is demonstrated, and the kinetic mass transfer contribution of this carbon molecular sieve adsorbent is calculated. Besides, differential adsorption enthalpies of several gases and light hydrocarbons were determined from the variation of retention volume with temperature. The data indicate close adsorption behaviors on the Carbobond porous layer adsorbent and on the carbon molecular sieve Carboxen support used to prepare the packed columns. Moreover, taking into account the in situ operating conditions of the experiment, a study of two columns with different porous layer thicknesses allowed one to optimize the separation of the target components and to select the column parameters compatible with the instrument constraints. Comparison with columns of similar selectivity shows that these capillary columns are the first ones able to perform the same work as the packed and micro-packed columns dedicated to the separation of this range of compounds in GC space exploration.

  4. Occurrence of aliphatic and polyaromatic hydrocarbons (PAHs) in Mytillus galloprovincialis from the traditional market in Marseille, France, by Gas Chromatography triplequadropole tandem Mass Spectrometry (GC-QQQ/MS)

    Science.gov (United States)

    Azis, M. Y.; Yelmiza; Asia, L.; Piram, A.; Bucharil, B.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Mediterranean mussel, Mytillusgalloprovincialis collected from the traditional market in Marseille, France,have been analysed using GC-QQQ/MS for their hydrocarbons (n-alkanes and polyaromatic hydrocarbons (PAHs)) extentwith two different solvent extraction, such as heptane:dichloromethane (HEP:DCM;1:1) and heptane:acetone (HEP:ACE; 1:1). The results showed hydrocarbons yielded from heptane:acetone extractionwere 28335 μg.kg- 1mussels dw (Ʃ n-alkanes C15-34) and 202 μg.kg-1mussels dw(ƩPAHs) while the yield from heptane:DCM extract was lower ca. 27026 μg.kg-1musselsdw and 133 μg.kg-1 mussels dw respectively from the Ʃn-alkanesC15-34and ƩPAHs. High hydrocarbon levels can be affected by the presence of lipids or other metabolites in mussels that have the same polarity with hydrocarbon compounds which has interferred the measurement. Several ratio parameter of n- alcanes and PAHs source in the mussels were evaluated to asses the origins of their hydrocarbons in mussels from which we suggested origins of hydrocarbons were pyrolytic and biogenic rather than petrogenic.

  5. Developing Mathematical Provisions for Assessment of Liquid Hydrocarbon Emissions in Emergency Situations

    Science.gov (United States)

    Zemenkova, M. Yu; Zemenkov, Yu D.; Shantarin, V. D.

    2016-10-01

    The paper reviews the development of methodology for calculation of hydrocarbon emissions during seepage and evaporation to monitor the reliability and safety of hydrocarbon storage and transportation. The authors have analyzed existing methods, models and techniques for assessing the amount of evaporated oil. Models used for predicting the material balance of multicomponent two-phase systems have been discussed. The results of modeling the open-air hydrocarbon evaporation from an oil spill are provided and exemplified by an emergency pit. Dependences and systems of differential equations have been obtained to assess parameters of mass transfer from the open surface of a liquid multicomponent mixture.

  6. Determination of polycyclic aromatic hydrocarbons in olive oil by a completely automated headspace technique coupled to gas chromatography-mass spectrometry.

    Science.gov (United States)

    Arrebola, Francisco J; Frenich, A Garrido; González Rodríguez, Manuel J; Bolaños, Patricia Plaza; Martínez Vidal, José L

    2006-06-01

    A new and completely automated method for the determination of ten relevant polycyclic aromatic hydrocarbons (PAHs) in olive oil is proposed using an extraction by the headspace (HS) technique. Quantification and confirmation steps are carried out by gas chromatography-mass spectrometry (GC-MS) combining simultaneously selected-ion monitoring (SIM) and tandem mass spectrometry (MS/MS). This combination offers on one hand an increased sensitivity and on the other hand, selective and reliable qualitative information. Sample pretreatment or clean-up are not necessary because the olive oil sample is put directly into an HS vial, automatically processed by HS and introduced into the GC-MS instrument for analysis. Because of its high selectivity and sensitivity, a triple-quadrupole (QqQ) detector coupled with the gas chromatograph allows us to limit handling. Each sample is completely processed in approximately 63 min (45 min for HS isolation and 18 min for GC-MS determination), a reduced time compared with previously published methods. The chemical and instrumental variables were preliminarily optimized using uncontaminated olive oil samples spiked with 25 microg kg(-1) of each target compound. The final method was validated to ensure the quality of the results. The precision was satisfactory, with relative standard deviation (RSD) values in the range 3-9%. Recovery rates ranged from 96 to 99%. Limits of detection (LOD) were calculated as 0.02-0.06 microg kg(-1) and the limits of quantification (LOQ) were obtained as 0.07-0.26 microg kg(-1). It must be mentioned that the LOD and LOQ are much lower than the maximum levels established by the European Union (EU) in oils and fats intended for direct human consumption or for use as an ingredient in foods, which are set at 2 microg kg(-1). All the figures of merit are completely in accordance with the latest EU legislation. This fact makes it possible to consider the proposed method as a useful tool for the control of PAHs in

  7. A Dual-Line Detection Rayleigh Scattering Diagnostic Technique for the Combustion of Hydrocarbon Fuels and Filtered UV Rayleigh Scattering for Gas Velocity Measurements

    Science.gov (United States)

    Otugen, M. Volkan

    1997-01-01

    Non-intrusive techniques for the dynamic measurement of gas flow properties such as density, temperature and velocity, are needed in the research leading to the development of new generation high-speed aircraft. Accurate velocity, temperature and density data obtained in ground testing and in-flight measurements can help understand the flow physics leading to transition and turbulence in supersonic, high-altitude flight. Such non-intrusive measurement techniques can also be used to study combustion processes of hydrocarbon fuels in aircraft engines. Reliable, time and space resolved temperature measurements in various combustor configurations can lead to a better understanding of high temperature chemical reaction dynamics thus leading to improved modeling and better prediction of such flows. In view of this, a research program was initiated at Polytechnic University's Aerodynamics Laboratory with support from NASA Lewis Research Center through grants NAG3-1301 and NAG3-1690. The overall objective of this program has been to develop laser-based, non-contact, space- and time-resolved temperature and velocity measurement techniques. In the initial phase of the program a ND:YAG laser-based dual-line Rayleigh scattering technique was developed and tested for the accurate measurement of gas temperature in the presence of background laser glare. Effort was next directed towards the development of a filtered, spectrally-resolved Rayleigh/Mie scattering technique with the objective of developing an interferometric method for time-frozen velocity measurements in high-speed flows utilizing the uv line of an ND:YAG laser and an appropriate molecular absorption filter. This effort included both a search for an appropriate filter material for the 266 nm laser line and the development and testing of several image processing techniques for the fast processing of Fabry-Perot images for velocity and temperature information. Finally, work was also carried out for the development of

  8. Seepage properties of a single rock fracture subjected to triaxial stresses

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Coupled properties of seepage and stress fields of rock fractures greatly influence the safety of geotechnical engineering work.Based on the closing defomation principle of a single rock fracture,equations describing relationships of aperture and triaxial stresses are developed,and coupled models of seepage and triaxial stresses are proposed.Seepage tests are conducted under triaxial stress conditions by adopting hard granite specimens with an artificial fracture.The results show that the normal stress,lateral stress and seepage pressure significantly affect the flow behavior of rock fractures,and that hydraulic conductivity decreases with increasing normal.stress,but increases with rising lateral stress or seepage pressure.In addition,an exponential function provides a good representation of the seepage characteristics of a single rock fracture subjected to triaxial stresses.

  9. Phase behaviour in water/hydrocarbon mixtures involved in gas production systems; etude des equilibres des systemes: eau-hydrocarbures-gaz acides dans le cadre de la production de gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chapoy, A.

    2004-11-15

    Inside wells, natural gases frequently coexist with water. The gases are in equilibrium with the sub-adjacent aquifer. Many problems are associated with the presence of water during the production, transport and processing of natural gases. Accurate knowledge of the thermodynamic properties of the water/hydrocarbon and water-inhibitor/hydrocarbon equilibria near the hydrate forming conditions, at sub-sea pipeline conditions and during the transport is crucial for the petroleum industry. An apparatus based on a static/analytic method combined with a dilutor apparatus to calibrate on the gas chromatograph (GC) detectors with water was used to measure the water content of binary systems (i.e.: water - methane, ethane - water, nitrogen - water...) as well of a synthetic hydrocarbon gas mixture (i.e.: 94% methane, 4% ethane and 2% n-butane) with and without inhibitor. This same apparatus was also used generate data of methane, ethane, propane, n-butane and nitrogen solubility in water and also the solubilities of a synthetic mixture in water. In-house software has been developed in order to fit and model the experimental data. (author)

  10. Seepage phenomena on Mars at subzero temperature

    Science.gov (United States)

    Kereszturi, Akos; Möhlmann, Diedrich; Berczi, Szaniszlo; Ganti, Tibor; Horvath, Andras; Kuti, Adrienn; Pocs, Tamas; Sik, Andras; Szathmary, Eors

    At the southern hemisphere of Mars seasonal slope structures emanating from Dark Dune Spots are visible on MGS MOC, and MRO HiRISE images. Based on their analysis two groups of streaks could be identified: diffuse and fan shaped ones forming in an earlier phase of local spring, probably by CO2 gas jets, and confined streaks forming only on steep slopes during a later seasonal phase. The dark color of the streaks may arise from the dark color of the dune grains where surface frost disappeared above them, or caused by the phase change of the water ice to liquid-like water, or even it may be influenced by the solutes of salts in the undercooled interfacial water The second group's morphology (meandering style, ponds at their end), morphometry, and related theoretical modelling suggest they may form by undercooled water that remains in liquid phase in a thin layer around solid grains. We analyzed sequence of images, temperature and topographic data of Russel (54S 12E), Richardson (72S 180E) and an unnamed crater (68S 2E) during southern spring. The dark streaks here show slow motion, with an average speed of meter/day, when the maximal daytime temperature is between 190 and 220 K. Based on thermophysical considerations a thin layer of interfacial water is inevitable on mineral surfaces under the present conditions of Mars. With 10 precipitable micrometer of atmospheric water vapor, liquid phase can be present down about 190 K. Under such conditions dark streaks may form by the movement of grains lubricatred by interfacial water. This possibility have various consequences on chemical, mechanical or even possible astrobiological processes on Mars. Acknowledgment: This work was supported by the ESA ECS-project No. 98004 and the Pro Renovanda Cultura Hungariae Foundation.

  11. Thermal Pyrolysis of Hydrocarbon Generation for Marine Hydrocarbon Sources in Marine Sequence of South China and Stable Carbon Isotopes of Gas Products%南方海相层系不同类型烃源(岩)生烃模拟实验及其产物同位素演化规律

    Institute of Scientific and Technical Information of China (English)

    王杰; 刘文汇; 腾格尔; 秦建中; 郑伦举

    2011-01-01

    利用常规高压釜热压模拟仪和仿真地层热压生排烃模拟仪对南方海相不同类型烃源进行生烃模拟实验,研究发现不同类型原油烃气产率最高,分散可溶有机质烃气产率次之,产率最低的为不同类型千酪根。不同类型烃源烃气产率与烃源的有机碳含量、可溶有机质含量高低、有机质类型有密切关系,与烃源原始成熟度具有较好负相关性。烃源碳同位素组成决定产物甲烷碳同位素组成的演化规律,碳同位素组成较轻的烃源其产物甲烷碳同位素组成总体上要轻于碳同位素组成较重烃源的甲烷碳同位素组成。不同类型烃源产物甲烷碳同位素组成随热模拟温度增高具有先变轻再变重的演化特征,但不会重于其烃源的碳同位素组成。乙烷等碳同位素组成也随着热模拟温度增高逐渐变重,演化至生烃高峰时,碳同位素组成接近于其烃源碳同位素组成,可以示踪烃源。当演化至高过成熟阶段,乙烷等δ^13C值大于其烃源碳同位素值,故不能仅用重烃碳同位素组成判断天然气母质类型。不同类型干酪根与可溶有机质CO2组分和同位素组成演化规律具有明显区别,可溶有机质生成的CO2和甲烷之间同位素分馏程度要比不同类型干酪根的大。在不同类型烃源生烃过程中,干酪根和液态烃碳同位素组成主要受母质类型控制,继承效应强,同位素分馏程度较小,具有很好的示踪意义,可以用于油源对比和烃源示踪研究。%The hydrous pyrolysis experiments for potential hydrocarbon sources in the marine sequence of south China were subjected in the high pressure and geological condition simulation vessels. The results indicate that the productivity of hydrocarbon gas generation for hydrocarbon sources is various, the highest productivity for crude oil (light oil and condensate) , the secondary productivity for the

  12. Effect of downward seepage on turbulent flow characteristics and bed morphology around bridge piers

    Science.gov (United States)

    Chavan, Rutuja; Sharma, Anurag; Kumar, Bimlesh

    2017-03-01

    In this work, experimental investigations have been pursued to analyse the influence of downward seepage on the turbulent characteristics of flow and corresponding changes in vortex structure around circular bridge pier in alluvial channel. Experiments were conducted in sand bed channel with circular piers of different sizes for no seepage, 10% seepage and 20% seepage cases. The measurement of turbulent flow statistics such as velocity and Reynolds stresses is found to be negative within the scour hole at upstream of the pier whereas application of downward seepage retards the reversal of the flow causing a decrement in the velocity and Reynolds stresses. Higher Reynolds shear stress prevails at the downstream side because of the production of wake vortices. Contribution of all bursting events to the total Reynolds shear stress production has been observed to increase with downward seepage. The analysis of integral scale suggest that size of eddies increases with seepage, which is responsible for increase in particle mobility. Initially rate of scouring is more which abatements gradually with expanding time as well as with the increased of downward seepage. Presence of downward seepage reduces the depth and length of vortex and shifts towards downstream side of the pier.

  13. Contact solid-phase microextraction with uncoated glass and polydimethylsiloxane-coated fibers versus solvent sampling for the determination of hydrocarbons in adhesion secretions of Madagascar hissing cockroaches Gromphadorrhina portentosa (Blattodea) by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Gerhardt, Heike; Schmitt, Christian; Betz, Oliver; Albert, Klaus; Lämmerhofer, Michael

    2015-04-03

    Molecular profiles of adhesion secretions of Gromphadorrhina portentosa (Madagascar hissing cockroach, Blattodea) were investigated by gas chromatography mass spectrometry with particular focus on a comprehensive analysis of linear and branched hydrocarbons. For this purpose, secretions from the tarsi (feet), possibly contributing to adhesion on smooth surfaces, and control samples taken from the tibiae (lower legs), which contain general cuticular hydrocarbons that are supposed to be not involved in the biological adhesion function, were analyzed and their molecular fingerprints compared. A major analytical difficulty in such a study constitutes the representative, spatially controlled, precise and reproducible sampling from a living insect as well as the minute quantities of insect secretions on both tarsi and tibiae. Thus, three different in vivo sampling methods were compared in terms of sampling reproducibility and extraction efficiency by replicate measurement of samples from tarsi and tibiae. While contact solid-phase microextraction (SPME) with a polydimethylsiloxane (PDMS) fiber showed higher peak intensities, a self-made uncoated glass fiber had the best repeatability in contact-SPME sampling. Chromatographic profiles of these two contact-SPME sampling methods were statistically not significantly different. Inter-individual variances were larger than potentially existing minor differences in molecular patterns of distinct sampling methods. Sampling by solvent extraction was time consuming, showed lower sensitivities and was less reproducible. In general, sampling by contact-SPME with a cheap glass fiber turned out to be a viable alternative to PDMS-SPME sampling. Hydrocarbon patterns of the tarsal adhesion secretions were qualitatively similar to those of epicuticular hydrocarbon profiles of the tibiae. However, hydrocarbons were in general less abundant in tarsal secretions than secretions from tibiae.

  14. Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

    African Journals Online (AJOL)

    Prof. Ogunji

    hydrocarbon polluted sediments and water .... ecosystem may result in selective increase or decrease in microbial population (Okpokwasili ... been implicated in degradation of hydrocarbons such as crude oil, polyaromatic hydrocarbons and.

  15. 30 CFR 250.1162 - When may I burn produced liquid hydrocarbons?

    Science.gov (United States)

    2010-07-01

    ... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1162 When may I burn produced liquid hydrocarbons...

  16. Correlation between hydrocarbon distribution and water-hydrocarbon ratio in Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng Zhou; Qingling Chen; Yuewu Tao; Huixin Weng

    2011-01-01

    In order to shorten the evaluation cycle of cobalt catalyst before the optimized catalyst is fixed on,a mathematical method is proposed to calculate weight percentage of C5+ hydrocarbons.Based on the carbide polymerization mechanism and the main hydrocarbons being linear alkanes and α-olefins,the correlation between hydrocarbon distribution and the molecular mass ratio of water to hydrocarbons is discussed.The result shows the ratio was within the range of 1.125-1.286 and the lower the ratio,the more gaseous hydrocarbons were obtained.Moreover,a linear equation between the weight percentage of C5+ hydrocarbons and the weight ratio of C5+ hydrocarbons to the total water is established.These results are validated by corresponding experiments.The weight percentage of C5+ hydrocarbons could be immediately calculated by this linear equation without detailed gas chromatography (GC) analysis of them.

  17. Geological records of redox change related to methane seepage in the Ulleung Basin, East Sea

    Science.gov (United States)

    Chun, J.; Ryu, B.; Bahk, J.; Choi, J.; Riedel, M.

    2012-12-01

    The sediment mounds related to columnar seismic blanking zone have been reported in the basin plain, reflecting the presence of near-surface gas hydrate and authigenic carbonates in the Ulleung Basin, East Sea. The mounds commonly consist of hemipelagic sediments and buried authigenic carbonates. Recently, exposed carbonate mound (~5 m wide and 2 -3 m high) was found in the site UBGH2-11 at water depth of ~2092 m. Six push cores (70-cm-long) were collected around the area of the exposed carbonate mound using ROV manipulators. The total nitrogen (TN), total carbon (TC), total organic carbon (TOC), and their carbon dioxide (δ13C) and nitrogen (δ15N) isotope values of core sediments were measured to identify the spatial distribution of organic matter related to methane seepages. The trace and rare earth elements of core sediments were analyzed to determine the redox conditions in seafloor sedimentary environments around the area of cold vents. Higher TOC contents (4-8%) were observed in three cores in the area around the exposed carbonate mound, whereas TOC contents ranged from 2-3% in other three cores, about 50 m away from the exposed carbonate mound. Highly negative δ13C values (-40 to -28 ‰) of organic matters show only one core located at the side of exposed carbonate mound. Higher Mn/Ti ratios suggest that the topmost parts of the core sediments outside the exposed carbonate mound were influenced by the effects of oxygenated bottom water. At other locations, there is no evidence of oxygenated bottom water. It suggests that the surface sediments formed under oxygen-depleted condition. Variation of Mo/Al and Co/Al ratios explains by fluctuation of redox conditions around the exposed carbonate mound in the site UBGH2-11. These results indicate that redox conditions of seafloor environments were locally influenced by methane seepages of cold vents associated with columnar seismic blanking zone in the Ulleung Basin.

  18. High Molecular Weight Petrogenic and Pyrogenic Hydrocarbons in Aquatic Environments

    Science.gov (United States)

    Abrajano, T. A., Jr.; Yan, B.; O'Malley, V.

    2003-12-01

    Geochemistry is ultimately the study of sources, movement, and fate of chemicals in the geosphere at various spatial and temporal scales. Environmental organic geochemistry focuses such studies on organic compounds of toxicological and ecological concern (e.g., Schwarzenbach et al., 1993, 1998; Eganhouse, 1997). This field emphasizes not only those compounds with potential toxicological properties, but also the geological systems accessible to the biological receptors of those hazards. Hence, the examples presented in this chapter focus on hydrocarbons with known health and ecological concern in accessible shallow, primarily aquatic, environments.Modern society depends on oil for energy and a variety of other daily needs, with present mineral oil consumption throughout the 1990s exceeding 3×109 t yr-1 (NRC, 2002). In the USA, e.g., ˜40% of energy consumed and 97% of transportation fuels are derived from oil. In the process of extraction, refinement, transport, use, and waste production, a small but environmentally significant fraction of raw oil materials, processed products, and waste are released inadvertently or purposefully into the environment. Because their presence and concentration in the shallow environments are often the result of human activities, these organic materials are generally referred to as "environmental contaminants." Although such reference connotes some form of toxicological or ecological hazard, specific health or ecological effects of many organic "environmental contaminants" remain to be demonstrated. Some are, in fact, likely innocuous at the levels that they are found in many systems, and simply adds to the milieu of biogenic organic compounds that naturally cycle through the shallow environment. Indeed, virtually all compounds in crude oil and processed petroleum products have been introduced naturally to the shallow environments as oil and gas seepage for millions of years ( NRC, 2002). Even high molecular weight (HMW) polyaromatic

  19. A preliminary evaluation model for reservoir hydrocarbon-generating potential established based on dissolved hydrocarbons in oilfield water

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A large number of oilfield water samples were analyzed in this work. Research on the relationship between the concentrations and distribution of dissolved hydrocarbons sug gested that the contents and composition of dissolved hydrocarbons varied with the hydrocar bon-generating potential of reservoirs. The concentrations of dissolved hydrocarbons were low in dry layers, water layers and gas-water layers, but high in gas reservoirs and oil reservoirs, especially in gas reservoirs with condensed oil. Series of carbon-number alkanes were usually absent in oilfield water from dry layers, water layers and gas-water layers but abundant in oil field water from oil-water reservoirs, gas reservoirs and oil reservoirs, whose carbon numbers varied most widely in oil reservoirs and least in gas reservoirs. A preliminary evaluation model for reservoir hydrocarbon-generating potential was established based on the characteristics of dissolved hydrocarbons in oilfield water to assist hydrocarbon exploration.

  20. Temporal Variation in Natural Gas Seep Rate and Influence Factors in the Lingtou Promontory Seep Field of the Northern South China Sea

    Directory of Open Access Journals (Sweden)

    Pengfei Di

    2014-01-01

    Full Text Available Natural hydrocarbon seeps in marine environment are important sources of methane and other greenhouse gases into the ocean and the atmosphere. This greenhouse gas seepage influences the global methane budget and global climate change. Hydrocarbon seeps on the shallow seabed produce a near-shore gas bubble zone along the western coast of Hainan Island, in the northern South China Sea. However, few studies on the quantitative value of the methane flux and on temporal variation and influence factors of hydrocarbon seeps have been conducted until now. This study describes the results of continuous gas vent measurements for 420 hours on the seabed of the Lingtou promontory shore. The amount of gas released from a single gas vent was 30.5 m3 during the measurement period. The gas flow rate ranged from 22 - 72 L h-1, with an average rate of 53.4 L h-1. The time series analyses of the 420-hour record clearly show three principal tidal components with periods of 5.4, 4.6, and 2.4 hours, which are the main factors controlling the gas flow rate. Low flow rates were associated with high tide and high flow rates associated with low tide. A 1-m increase in seawater height results in a decrease of 20 - 30 L h-1 or 35 - 56% of the hourly flow rate. Therefore, the changes in gas volume escape from the pore could be attributed to the hydrostatic pressure effect induced by water depth. This dominant mechanism controlled pore activation as well as the gas flow rate, suggesting that in the marine environment, especially the shallow-water shelf area, sea level changes may result in great variations in methane release into the ocean and atmosphere.

  1. Apparatus for hydrocarbon extraction

    Science.gov (United States)

    Bohnert, George W.; Verhulst, Galen G.

    2013-03-19

    Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

  2. Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tzu-Ting, E-mail: d89844001@ntu.edu.tw [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China); Lin, Shaw-Tao [Department of Applied Chemistry, Providence University, No. 200 Chung-Chi Rd., Salu Dist., Taichung City 43301, Taiwan (China); Lin, Tser-Sheng [Department of Safety, Health, and Environmental Engineering, National United University, 2 Lien Da, Maioli 360, Taiwan (China); Chung, Hua-Yi [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China)

    2015-02-15

    The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17–78.72 mg/g, 26,139.80–35,932.98 and 5735.22–13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26–83.70% and 16.30–29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82–797.76 ng/g) was approximately 6.92–25.08 times higher than that of the gaseous phase (26.27–36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO{sub 3}) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency. - Highlights: • PAHs emissions are influenced by mosquito coils containing various atomic H/C ratios. • The PAHs generated by burning mosquito coils mainly occur in the gaseous phase. • Total TEQ emission factors of PAHs mainly consisted of the particulate phase (> 87%). • The BaP and BaA accounted for 71.13–77.28% of the total TEQ emission factors. • Special PAH ratios were regarded as characteristic ratios for burning mosquito coil.

  3. Potentials and Exploration Prospect of China's Hydrocarbon Resources

    Institute of Scientific and Technical Information of China (English)

    ZhangYiwei

    2004-01-01

    The potentials of China's hydrocarbon resources has risen as an important factor influencing the current policies of the country. China's oil industry is a developing industry. Gas reservoirs can be classified in light of their accumulation mechanisms into six types: water-sealed gas, hydrate, dissolved gas, conventional entrapped gas, capillary gas and adsorbed gas.

  4. Bubble composition of natural gas seeps discovered along the Cascadia Continental Margin

    Science.gov (United States)

    Baumberger, T.; Merle, S. G.; Embley, R. W.; Seabrook, S.; Raineault, N.; Lilley, M. D.; Evans, L. J.; Walker, S. L.; Lupton, J. E.

    2016-12-01

    Gas hydrates and gas-filled pockets present in sedimentary deposits have been recognized as large reservoirs for reduced carbon in the Earth's crust. This is particularly relevant in geological settings with high carbon input, such as continental margins. During expedition NA072 on the E/V Nautilus (operated by the Ocean Exploration Trust Inc.) in June 2016, the U.S. Cascadia Continental Margin (Washington, Oregon and northern California) was explored for gas seepage from sediments. During this expedition, over 400 bubble plumes at water depths ranging from 125 and 1640 m were newly discovered, and five of them were sampled for gas bubble composition using specially designed gas tight fluid samplers mounted on the Hercules remotely operated vehicle (ROV). These gas bubble samples were collected at four different depths, 494 m (rim of Astoria Canyon), 615 and 620 m (SW Coquille Bank), 849 m (floor of Astoria Canyon) and 1227 m (Heceta SW). At the two deeper sites, exposed hydrate was present in the same area where bubbles were seeping out from the seafloor. Other than the escaping gas bubbles, no other fluid flow was visible. However, the presence of bacterial mats point to diffuse fluid flow present in the affected area. In this study we present the results of the currently ongoing geochemical analysis of the gas bubbles released at the different sites and depths. Noble gas analysis, namely helium and neon, will give information about the source of the helium as well as about potential fractionation between helium and neon associated with gas hydrates. The characterization of these gas samples will also include total gas (CO2, H2, N2, O2, Ar, CH4 and other hydrocarbons) and stable isotope analysis (C and H). This dataset will reveal the chemical composition of the seeping bubbles as well as give information about the possible sources of the carbon contained in the seeping gas.

  5. Biodegradation of polycyclic hydrocarbons by Phanerochaete chrysosporium

    Science.gov (United States)

    The ability of the white rot fungus Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons (PAHs) that are present in anthracene oil (a distillation product obtained from coal tar) was demonstrated. Analysis by capillary gas chromatography and high-performance li...

  6. Biodegradation of polycyclic hydrocarbons by Phanerochaete chrysosporium

    Science.gov (United States)

    The ability of the white rot fungus Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons (PAHs) that are present in anthracene oil (a distillation product obtained from coal tar) was demonstrated. Analysis by capillary gas chromatography and high-performance li...

  7. Seepage into an Underground Opening Constructed in Unsaturated Fractured Rock Under Evaporative Conditions

    Energy Technology Data Exchange (ETDEWEB)

    R. C. Trautz; Joseph S. Y. Wang

    2001-06-07

    Liquid-release tests, performed in boreholes above an underground opening constructed in unsaturated fractured rock, are used in this study to evaluate seepage into a waste emplacement drift. Evidence for the existence of a capillary barrier at the ceiling of the drift is presented, based on field observations (including spreading of the wetting front across the ceiling and water movement up fractures exposed in the ceiling before seepage begins). The capillary barrier mechanism has the potential to divert water around the opening, resulting in no seepage when the percolation flux is at or below the seepage threshold flux. Liquid-release tests are used to demonstrate that a seepage threshold exists and to measure the magnitude of the seepage threshold flux for three test zones that seeped. The seepage data are interpreted using analytical techniques to estimate the test-specific strength of the rock capillary forces ({alpha}{sup -1}) that prevent water from seeping into the drift. Evaporation increases the seepage threshold flux making it more difficult for water to seep into the drift and producing artificially inflated {alpha}{sup -1} values. With adjustments for evaporation, the minimum test-specific threshold is 1,600 mm/yr with a corresponding {alpha}{sup -1} of 0.027 m.

  8. H-VERSION ADAPTIVE FINITE ELEMENT METHOD FOR THREE-DIMENSIONAL SEEPAGE PROBLEM

    Institute of Scientific and Technical Information of China (English)

    Feng Xue-min; Chen Sheng-hong

    2003-01-01

    The h-version adaptive finite element method for 3-D seepage problem is presented in this paper.The adaptive system includes 4 modules: 3-D mesh generation, finite element analysis for 3-D seepage, mesh error estimation and post-process.The effectiveness of this system is verified by the given example.

  9. Direct-immersion solid-phase microextraction coupled to fast gas chromatography mass spectrometry as a purification step for polycyclic aromatic hydrocarbons determination in olive oil.

    Science.gov (United States)

    Purcaro, Giorgia; Picardo, Massimo; Barp, Laura; Moret, Sabrina; Conte, Lanfranco S

    2013-09-13

    The aim of the present work was to optimize a preparation step for polycyclic aromatic hydrocarbons in a fatty extract. Solid-phase microextraction is an easy preparation technique, which allows to minimize solvent consumption and reduce sample manipulation. A Carbopack Z/polydimethylsiloxane fiber, particularly suitable for extraction of planar compounds, was employed to extract polycyclic aromatic hydrocarbons from a hexane solution obtained after a previous extraction with acetonitrile from oil, followed by a liquid-liquid partition between acetonitrile and hexane. The proposed method was a rapid and sensitive solution to reduce the interference of triglycerides saving the column life and avoiding frequent cleaning of the mass spectrometer ion source. Despite the non-quantitative extraction of polycyclic aromatic hydrocarbons from oil using acetonitrile, the signal-to-noise ratio was significantly improved obtaining a limit of detection largely below the performance criteria required by the European Union legislation.

  10. Low-temperature gas from marine shales: wet gas to dry gas over experimental time

    Directory of Open Access Journals (Sweden)

    Jarvie Daniel M

    2009-11-01

    Full Text Available Abstract Marine shales exhibit unusual behavior at low temperatures under anoxic gas flow. They generate catalytic gas 300° below thermal cracking temperatures, discontinuously in aperiodic episodes, and lose these properties on exposure to trace amounts of oxygen. Here we report a surprising reversal in hydrocarbon generation. Heavy hydrocarbons are formed before light hydrocarbons resulting in wet gas at the onset of generation grading to dryer gas over time. The effect is moderate under gas flow and substantial in closed reactions. In sequential closed reactions at 100°C, gas from a Cretaceous Mowry shale progresses from predominately heavy hydrocarbons (66% C5, 2% C1 to predominantly light hydrocarbons (56% C1, 8% C5, the opposite of that expected from desorption of preexisting hydrocarbons. Differences in catalyst substrate composition explain these dynamics. Gas flow should carry heavier hydrocarbons to catalytic sites, in contrast to static conditions where catalytic sites are limited to in-place hydrocarbons. In-place hydrocarbons and their products should become lighter with conversion thus generating lighter hydrocarbon over time, consistent with our experimental results. We recognize the similarities between low-temperature gas generation reported here and the natural progression of wet gas to dry gas over geologic time. There is now substantial evidence for natural catalytic activity in source rocks. Natural gas at thermodynamic equilibrium and the results reported here add to that evidence. Natural catalysis provides a plausible and unique explanation for the origin and evolution of gas in sedimentary basins.

  11. Hydrogeochemistry of Maine seepage lakes and related groundwaters

    Science.gov (United States)

    Stauffer, Robert E.; Wittchen, Bruce D.

    1992-10-01

    Southeastern Maine contains numerous small seepage lakes (no perennial surface inflows or outflows), set in felsic, glacial deposits (eskers, pitted outwash, glacio-marine deltaic terraces) dating from the Wisconsin glacial retreat ca. 12 500 years B.P. The modern landscape is either forested or maintained as low blueberry heath by semi-annual mowing and burning. Although local precipitation is currently moderately acidic (volume-weighted pH ≈ 4.5), spring waters issuing from the glacial deposits are only weakly acidic (6.1 Na > Mg > K, the same as for upland granitic terrane in the same region. Springwater composition is temporally stable but geographically variable. The most dilute springwaters drain blueberry barrens. Here, chemical weathering is limited by available acidity as evidenced by the relatively high final pHs (> 6.3) and low concentrations of strong oxy-anions (nitrate, sulfate) and dissolved inorganic carbon (DIC 100 cm year -1) for groundwater discharge lakes. Approximately 88% of Si inputs to regional seepage lakes is retained in the sediments. Non-marine sulfate is lowest in groundwater discharge lakes containing the highest concentrations of BC and F, and featuring the shortest hydraulic residence times, suggesting that S retention in lake sediments is currently less efficient than in the adjoining terrestrial soils and vegetation.

  12. Seismic Stability of Subsea Tunnels Subjected to Seepage

    Directory of Open Access Journals (Sweden)

    Xuansheng Cheng

    2014-01-01

    Full Text Available Strength reduction method and ADINA software are adopted to study the stability of submarine tunnel structures subjected to seepage and earthquake under different seawater depths and overlying rock strata thicknesses. First, the excess pore water pressure in the rock mass is eliminated through consolidation calculation. Second, dynamic time-history analysis is performed by inputting the seismic wave to obtain the maximum horizontal displacement at the model top. Finally, static analysis is conducted by inputting the gravity and the lateral border node horizontal displacement when the horizontal displacement is the largest on the top border. The safety factor of a subsea tunnel structure subjected to seepage and earthquake is obtained by continuously reducing the shear strength parameters until the calculation is not convergent. The results show that the plastic zone initially appears at a small scope on the arch feet close to the lining structure and at both sides of the vault. Moreover, the safety factor decreases with increasing seawater depth and overlying rock strata thickness. With increasing seawater depth and overlying rock strata thickness, maximum main stress, effective stress, and maximum displacement increase, whereas displacement amplitude slightly decreases.

  13. Radioactive Seepage through Groundwater Flow from the Uranium Mines, Namibia

    Directory of Open Access Journals (Sweden)

    Tamiru Abiye

    2017-02-01

    Full Text Available The study focused on the seepage of uranium from unlined tailing dams into the alluvial aquifer in the Gawib River floodplain in Namibia where the region solely relies on groundwater for its economic activities as a result of arid climatic condition. The study reviewed previous works besides water sample collection and analyses for major ions, metals and environmental isotopes in addition to field tests on physico-chemical parameters (pH, Electrical Conductivity, Redox and T. Estimation of seepage velocity (true velocity of groundwater flow has been conducted in order to understand the extent of radioactive plume transport. The hydrochemistry, stable isotopes and tritium results show that there is uranium contamination from the unlined uranium tailings in the Gawib shallow aquifer system which suggests high permeability of the alluvial aquifer facilitating groundwater flow in the arid region. The radioactive contaminants could spread into the deeper aquifer system through the major structures such as joints and faults. The contamination plume could also spread downstream into the Swakop River unless serious interventions are employed. There is also a very high risk of the plume to reach the Atlantic Ocean through seasonal flash floods that occurs in the area.

  14. Cuticular hydrocarbons from the bed bug Cimex lectularius L.

    Science.gov (United States)

    Pentane extracts of male and female bed bugs were analyzed by gas chromatography and mass spectrometry in an effort to identify cuticular hydrocarbons. Seventeen hydrocarbons accounting for nearly 99% of the compounds eluting in the cuticular hydrocarbon region were identified. The sample contained ...

  15. 40 CFR 503.44 - Operational standard-total hydrocarbons.

    Science.gov (United States)

    2010-07-01

    ... hydrocarbons. 503.44 Section 503.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... standard—total hydrocarbons. (a) The total hydrocarbons concentration in the exit gas from a sewage sludge incinerator shall be corrected for zero percent moisture by multiplying the measured total...

  16. GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Millings, M.; Denham, M.; Looney, B.

    2012-05-08

    From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors

  17. Method for estimating spatially variable seepage loss and hydraulic conductivity in intermittent and ephemeral streams

    Science.gov (United States)

    Niswonger, R.G.; Prudic, D.E.; Fogg, G.E.; Stonestrom, D.A.; Buckland, E.M.

    2008-01-01

    A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and along the channel. Water redistribution in the unsaturated zone is also represented in the model. Sensitivity of the streamflow front velocity to parameters used for calculating seepage loss and for routing streamflow shows that the streambed hydraulic conductivity has the greatest sensitivity for moderate to large seepage loss rates. Channel roughness, geometry, and slope are most important for low seepage loss rates; however, streambed hydraulic conductivity is still important for values greater than 0.008 m/d. Two example applications are presented to demonstrate the utility of the method. Copyright 2008 by the American Geophysical Union.

  18. Distributed optical fiber-based theoretical and empirical methods monitoring hydraulic engineering subjected to seepage velocity

    Science.gov (United States)

    Su, Huaizhi; Tian, Shiguang; Cui, Shusheng; Yang, Meng; Wen, Zhiping; Xie, Wei

    2016-09-01

    In order to systematically investigate the general principle and method of monitoring seepage velocity in the hydraulic engineering, the theoretical analysis and physical experiment were implemented based on distributed fiber-optic temperature sensing (DTS) technology. During the coupling influence analyses between seepage field and temperature field in the embankment dam or dike engineering, a simplified model was constructed to describe the coupling relationship of two fields. Different arrangement schemes of optical fiber and measuring approaches of temperature were applied on the model. The inversion analysis idea was further used. The theoretical method of monitoring seepage velocity in the hydraulic engineering was finally proposed. A new concept, namely the effective thermal conductivity, was proposed referring to the thermal conductivity coefficient in the transient hot-wire method. The influence of heat conduction and seepage could be well reflected by this new concept, which was proved to be a potential approach to develop an empirical method monitoring seepage velocity in the hydraulic engineering.

  19. Improved similarity criterion for seepage erosion using mesoscopic coupled PFC-CFD model

    Institute of Scientific and Technical Information of China (English)

    倪小东; 王媛; 陈珂; 赵帅龙

    2015-01-01

    Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics (PFC−CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC−CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.

  20. Hydrophobic encapsulation of hydrocarbon gases.

    Science.gov (United States)

    Leontiev, Alexander V; Saleh, Anas W; Rudkevich, Dmitry M

    2007-04-26

    [reaction: see text] Encapsulation data for hydrophobic hydrocarbon gases within a water-soluble hemicarcerand in aqueous solution are reported. It is concluded that hydrophobic interactions serve as the primary driving force for the encapsulation, which can be used for the design of gas-separating polymers with intrinsic inner cavities.

  1. Methane Seepage at Hyperalkaline Springs in the Ronda Peridotite Massif (Spain)

    Science.gov (United States)

    Etiope, G.; Vadillo, I.; Whiticar, M. J.; Marques, J. M.; Carreira, P. M.; Tiago, I.; Benavente, J.; Jimenez, P.; Urresti, B.

    2014-12-01

    Methane-rich, hyperalkaline spring waters and bubbling pools have been sampled in the Ronda peridotite massif in southern Spain. Water chemistry (T: 17.1-21.5 ºC; pH: 10.7-11.7; DO: migration pathways along faults. Similar 'dry' seepage of abiotic gas was observed in the Philippines, New Zealand, Turkey and Italy. Like other land-based serpentinization systems, the Ronda peridotite massif is characterized by low heat flow (<40 mW/m2), with temperatures <60°C at depths of 1.5 km. At these low T and high pH conditions, CO32- is the only available carbon source dissolved in the water, and unlikely contributes to catalysed Fischer-Tropsch Type reactions. Methane production from CO2 hydrogenation in a gas phase system (unsaturated fractured rocks) cannot be excluded. The presence of ruthenium-enriched chromitites in the Ronda peridotites may support the hypothesis that CH4 is produced by CO2 hydrogenation catalyzed by Ru minerals, even at temperatures below 100°C, as demonstrated in recent laboratory experiments (Etiope and Ionescu, 2014, Geofluids, in press).

  2. Mineralogical and geochemical characterization of hydrocarbon seep sediments from the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Canet, Carles; Prol-Ledesma, Rosa Maria; Mortera-Gutierrez, Carlos; Linares, Carlos [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico); Escobar-Briones, Elva [Instituto de Ciencias del Mar y Limnologia, Unidad Academica Sistemas Oceanograficos y Costeros, A. P. 70-305 Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico); Lozano-Santa Cruz, Rufino; Cienfuegos, Edith; Morales-Puente, Pedro [Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Coyoacan 04510, Mexico (Mexico)

    2006-06-15

    A common characteristic of the Gulf of Mexico (GOM) seafloor, hydrocarbon seepage produces asphalt volcanism, brine pools, gas hydrates and authigenic carbonates. We studied authigenic carbonates from two areas: Green Canyon (Louisiana slope, 1000mbsl) and the Chapopote diapir (abyssal plain, southwestern GOM, 2900mbsl). Carbonates consist of oily, matrix-supported limestones with variable porosity and a fine-grained matrix of calcite. They occur in Green Canyon as both concretions formed below the seafloor and as slabs of seabed pavements. In each case, the carbonates are mudstones with a mud matrix consisting of high-Mg calcite, disseminated pyrite and detrital quartz. The carbonate slabs have vug microporosity and contain barite that occurs as vug lining. The precipitation of barite results from a reaction between barium-rich and sulfate-free seep fluids and downwards-diffusing seawater. The carbonates in Chapopote occur in relation to tar flows and form crusts of wackestones with bivalve shells. The matrix is composed by low-Mg calcite with disseminated pyrite and detrital quartz. The carbonate mud shows depletion in {sup 13}C, with {delta}{sup 13}C between -36.9%% and -23.0%%. Carbonates precipitate as a consequence of anaerobic methane oxidation coupled with seawater sulfate reduction. {delta}{sup 18}O values (3.4-4.4%%) suggest precipitation at temperatures between 5 and 9{sup o}C. (author)

  3. Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran's Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL(-1). The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry.

  4. Arguments for a Comprehensive Laboratory Research Subprogram on Hydrocarbon Gas Hydrates and Hydrate-Sediment Aggregates in the 2005-2010 DOE Methane Hydrate R & D Program

    Science.gov (United States)

    Kirby, S. H.

    2005-12-01

    Field observations of natural hydrocarbon clathrate hydrates, including responses to drilling perturbations of hydrates, well logging and analysis of drill core, and field geophysics are, combined with theoretical modeling, justifiably key activities of the authorized 2005-2010 DOE Methane Hydrate Program. It is argued in this presentation that sustained fundamental laboratory research amplifies, extends and verifies results obtained from field and modeling investigations and does so in a cost-effective way. Recent developments of hydrocarbon clathrate hydrate and sediment aggregate synthesis methods, applications of in-situ optical cell, Raman, NMR, x-ray tomography and neutron diffraction techniques, and cryogenic x-ray and SEM methods re-enforce the importance of such lab investigations. Moreover, there are large data gaps for hydrocarbon-hydrate and hydrate-sediment-aggregate properties. We give three examples: 1) All natural hydrocarbon hydrates in sediment core have been altered to varying degrees by their transit, storage, depressurization, and subsequent lab investigations, as are well-log observations during drilling operations. Interpretation of drill core properties and structure and well logs are also typically not unique. Emulations of the pressure-temperature-deformation-time histories of synthetic samples offer a productive way of gaining insight into how natural samples and logging measurements may be compositionally and texturally altered during sampling and handling. 2) Rock physics models indicate that the effects of hydrates on sediment properties depend on the manner in which hydrates articulate with the sediment matrix (their conformation). Most of these models have not been verified by direct testing using hydrocarbon hydrates with conformation checked by optical cell observations or cryogenic SEM. Such tests are needed and technically feasible. 3) Modeling the effects of exchanges of heat, multiphase fluid fluxes, and deformation involve

  5. On the Zinc Air Battery Electrode Surface Seepage Phenomenon%锌空气电池电极表面渗液现象的研究

    Institute of Scientific and Technical Information of China (English)

    杨永青; 徐献芝; 李清宇; 刘晓毅

    2012-01-01

    渗液问题是锌空气电池的主要问题之一.本文通过如下实验:聚四氟乙烯膜(PTFE,poly tetra fluoro ethylene)表面特性实验、电池风冷放电、空气电极电压实验和类列斯实验,对可能影响电池渗液的因素进行了研究.这些因素包括:PTFE膜、温度、电压、电荷总量、电解质溶液.实验结果表明:PTFE膜经过KOH溶液浸泡一段时间后,其接触角会显著变小,疏水性变差;温度和电压会对渗液现象产生影响;在各类电解质溶液中,KOH溶液渗液最严重;放电过程中的电荷总量对渗液问题基本没影响.实验结果分析得出,这类电池渗液主要是由于上述因素导致电解液表面张力变化,引起气液界面移动导致的.%Seepage is one of the main problems of zinc air battery. Factors that may affect the battery seepage were investigated through following experiments: PTFE (poly tetra fluoro ethylene) film surface properties experiment, battery cooling discharge experiment, air electrode voltage experiment and Antilliean electro-osmosis test. These involved factors include PTFE film, temperature, voltaget charge quantity and electrolyte solution. Experimental results show that after soak in KOH solution for a period of time, the contact angle of PTFE film becomes significantly small and its hydrophobic property deteriorates; temperature and voltage indeed have influence on seepage phenomenon; KOH solution seepage is the most serious in all kinds of electrolyte solution) the total charge in discharge process basically has no influence on seepage. Based on analysis of experimental results, it is concluded that the battery seepage is caused by the change of electrolyte solution surface tension induced by above factors, which results in gas-liquid interface movement, Above results are valuable for improving the performance of zinc air battery.

  6. Environmental information document: Savannah River Laboratory Seepage Basins

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, B.F.; Looney, B.B.; Simmons, R.V.; Bledsoe, H.W.

    1987-03-01

    This document provides environmental information on postulated closure options for the Savannah River Laboratory Seepage Basins at the Savannah River Plant and was developed as background technical documentation for the Department of Energy`s proposed Environmental Impact Statement (EIS) on waste management activities for groundwater protection at the plant. The results of groundwater and atmospheric pathway analyses, accident analysis, and other environmental assessments discussed in this document are based upon a conservative analysis of all foreseeable scenarios as defined by the National Environmental Policy Act (CFR, 1986). The scenarios do not necessarily represent actual environmental conditions. This document is not meant to be used as a closure plan or other regulatory document to comply with required federal or state environmental regulations.

  7. Time-Dependent Sediment Transport Subjected to Downward Seepage

    Institute of Scientific and Technical Information of China (English)

    刘小谢; 赵以明; 白玉川

    2014-01-01

    Experiments were conducted using cohesionless sand particles with median diameter of 0.48 mm to inves-tigate the time variation of sediment transport rate under the influence of local downward seepage. The experimental results show that the bedload transport rate in terms of volumetric sediment transport rate per unit width increased rapidly with time in the presence of suction, eventually reaching a peak beyond which it started to decrease. The trend of reduction was significantly reduced beyond 8 400 s after the test started. The analytical expression was derived in terms of dimensionless sediment transport rate and dimensionless time. The hypothesized relationships were compared with the experimental data, indicating a good agreement with each other.

  8. Savannah River Laboratory Seepage Basins: Waste site assessment report

    Energy Technology Data Exchange (ETDEWEB)

    Haselow, J.S.; Looney, B.B.; Nichols, R.L.

    1989-09-05

    This Waste Site Assessment for the SRL Seepage Basins is the second in a series of documents being prepared to support development of an appropriate closure plan for these basins. The closure of these basins will be designed to provide protection to human health and the environment and to meet the provisions of the Consent Decree. A Technical Data Summary for these basins has already been submitted as part of the Consent Decree. This Site Assessment Report includes a waste site characterization, and a discussion of closure options for the basins. A closure option is recommended in this report, but details of the recommended closure are not provided in this report since they will be provided in a subsequent closure plan. The closure plan is the third document required under the Consent Decree. 18 refs., 16 figs., 10 tabs.

  9. Progress of research on hydrocarbon accumulation of tight sand gas and several issues for concerns%致密砂岩气成藏研究进展及值得关注的几个问题

    Institute of Scientific and Technical Information of China (English)

    郭迎春; 庞雄奇; 陈冬霞; 姜福杰; 汤国民

    2013-01-01

    Continuous tight sand gas is a significant unconventional resource for natural gas .To understand the progress of geological research on this kind of gas reservoir ,this paper summarized the criteria for identification of tight sand reser-voirs,their classification ,geological characteristics ,elements of hydrocarbon accumulation ,and trapping mechanisms .The current criteria for identivation of continuous tight sand gas reservoirs does not take accumulation conditions into conside -ration.The real critical conditions of tight sand gas change along with hydrocarbon accumulation conditions .The key ele-ments of hydrocarbon accumulation in tight gas reservoir involve hydrocarbon source rock ,tight sandstone close to source rock and stable tectonic environment .It should be noted that the nature of tight sandstone is nano-micro scale pore throat and the percentage of pore throats is about the same as that of pores ,and that abnormal pressure is not an essential differ-ence between tight sand gas reservoir and conventional gas reservoir .Several key issues concerning continuous tight sand gas accumulation are presented .The first is study on dynamic trapping mechanism for tight sand gas reservoir ,i.e.the force balance between driving force(gas pressure)and resistance(capillary force,viscous force and formation water pres-sure) at the interface of gas water inversion .The quantitative description and simulation of evolution of these forces are particularly important .The second is the research on the mechanism and process of adjustment of tight sand gas reservoir as well as restoration of the original tight sand gas reservoir .The restoration of the original reservoir can be realized by means of force balance relation at the interface of gas water inversion .All of the late adjustment and modification were realized through changing the critical conditions of gas water inversion .The third is study of the control of sandbodies with relatively high porosity and

  10. Heterogeneous seepage at the Nopal I natural analogue site, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, Patrick F.; Cook, Paul J.; Ghezzehei, Teamrat A.; Rodriguez, J. Alfredo; Villalba, Lourdes; de la Garza, Rodrigo

    2008-10-25

    An integrated field, laboratory, and modeling study of the Pena Blanca (Chihuahua, Mexico) natural analogue site is being conducted to evaluate processes that control the mobilization and transport of radionuclides from a uranium ore deposit. One component of this study is an evaluation of the potential for radionuclide transport through the unsaturated zone (UZ) via a seepage study in an adit at the Nopal I uranium mine, excavated 10 m below a mined level surface. Seasonal rainfall on the exposed level surface infiltrates into the fractured rhyolitic ash-flow tuff and seeps into the adit. An instrumented seepage collection system and local automated weather station permit direct correlation between local precipitation events and seepage within the Nopal I +00 adit. Monitoring of seepage within the adit between April 2005 and December 2006 indicates that seepage is highly heterogeneous with respect to time, location, and quantity. Within the back adit area, a few zones where large volumes of water have been collected are linked to fast flow path fractures (0-4 h transit times) presumably associated with focused flow. In most locations, however, there is a 1-6 month time lag between major precipitation events and seepage within the adit, with longer residence times observed for the front adit area. Seepage data obtained from this study will be used to provide input to flow and transport models being developed for the Nopal I hydrogeologic system.

  11. A modified calculation model for groundwater flowing to horizontal seepage wells

    Indian Academy of Sciences (India)

    Wei Wang; Peng Chen; Qingqing Zheng; Xinyu Zheng; Kunming Lu

    2013-04-01

    The simulation models for groundwater flowing to horizontal seepage wells proposed by Wang and Zhang (2007) are based on the theory of coupled seepage-pipe flow model which treats the well pipe as a highly permeable medium. However, the limitations of the existing model were found during applications. Specifically, a high-resolution grid is required to depict the complex structure of horizontal seepage wells; the permeability of the screen or wall material of radiating bores is usually neglected; and the irregularly distributed radiating bores cannot be accurately simulated. A modified calculation model of groundwater flowing to a horizontal seepage well is introduced in this paper. The exchange flow between well pipe and aquifer couples the turbulent flow inside the horizontal seepage well with laminar flow in the aquifer. The modified calculation model can reliably calculate the pumpage of a real horizontal seepage well. The characteristics of radiating bores, including the diameter, the permeability of screen material and irregular distribution of radiating bores, can be accurately depicted using the modified model that simulates the scenario in which several horizontal seepage wells work together.

  12. DRIFT-SCALE COUPLED PROCESSES (DST AND TH SEEPAGE) MODELS

    Energy Technology Data Exchange (ETDEWEB)

    J.T. Birkholzer; S. Mukhopadhyay

    2005-01-13

    The purpose of this report is to document drift-scale modeling work performed to evaluate the thermal-hydrological (TH) behavior in Yucca Mountain fractured rock close to waste emplacement drifts. The heat generated by the decay of radioactive waste results in rock temperatures elevated from ambient for thousands of years after emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, giving rise to water redistribution and altered flow paths. The predictive simulations described in this report are intended to investigate fluid flow in the vicinity of an emplacement drift for a range of thermal loads. Understanding the TH coupled processes is important for the performance of the repository because the thermally driven water saturation changes affect the potential seepage of water into waste emplacement drifts. Seepage of water is important because if enough water gets into the emplacement drifts and comes into contact with any exposed radionuclides, it may then be possible for the radionuclides to be transported out of the drifts and to the groundwater below the drifts. For above-boiling rock temperatures, vaporization of percolating water in the fractured rock overlying the repository can provide an important barrier capability that greatly reduces (and possibly eliminates) the potential of water seeping into the emplacement drifts. In addition to this thermal process, water is inhibited from entering the drift opening by capillary forces, which occur under both ambient and thermal conditions (capillary barrier). The combined barrier capability of vaporization processes and capillary forces in the near-field rock during the thermal period of the repository is analyzed and discussed in this report.

  13. Drift-Scale Coupled Processes (DST and TH Seepage) Models

    Energy Technology Data Exchange (ETDEWEB)

    J. Birkholzer; S. Mukhopadhyay

    2004-09-29

    The purpose of this report is to document drift-scale modeling work performed to evaluate the thermal-hydrological (TH) behavior in Yucca Mountain fractured rock close to waste emplacement drifts. The heat generated by the decay of radioactive waste results in rock temperatures elevated from ambient for thousands of years after emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, giving rise to water redistribution and altered flow paths. The predictive simulations described in this report are intended to investigate fluid flow in the vicinity of an emplacement drift for a range of thermal loads. Understanding the TH coupled processes is important for the performance of the repository because the thermally driven water saturation changes affect the potential seepage of water into waste emplacement drifts. Seepage of water is important because if enough water gets into the emplacement drifts and comes into contact with any exposed radionuclides, it may then be possible for the radionuclides to be transported out of the drifts and to the groundwater below the drifts. For above-boiling rock temperatures, vaporization of percolating water in the fractured rock overlying the repository can provide an important barrier capability that greatly reduces (and possibly eliminates) the potential of water seeping into the emplacement drifts. In addition to this thermal process, water is inhibited from entering the drift opening by capillary forces, which occur under both ambient and thermal conditions (capillary barrier). The combined barrier capability of vaporization processes and capillary forces in the near-field rock during the thermal period of the repository is analyzed and discussed in this report.

  14. Transient hydrogeological controls on the chemistry of a seepage lake

    Science.gov (United States)

    Krabbenhoft, David P.; Webster, Katherine E.

    1995-01-01

    A solute mass balance method was used to estimate groundwater inflow and outflow rates for Nevins Lake, Michigan, a seepage lake in the upper peninsula that historically has shown extremely variable water chemistry compared with most other seepage lakes. A 4-year study (1989–1992) of the hydrology and geochemistry of Nevins Lake and its contiguous groundwater system revealed that changes in the mass of dissolved solutes are the result of annual hydraulic gradient reversals. A pronounced acidification of Nevins Lake from 1986 to 1988 was likely caused by drought-induced diminished groundwater inflow rates. In this study, dissolved calcium (the major cation in water of Nevins Lake, groundwater, and precipitation) was used for estimating mass flow rates. During the 1989–1992 period, Nevins Lake showed a reproducible annual cycle in calcium mass. Immediately following spring snowmelt and the resulting hydraulic gradient reversal, the mass of dissolved calcium in the lake increases rapidly, and then it decreases steadily throughout the summer and early fall, at which time the lake becomes hydraulically mounded and receives no groundwater inflow. Groundwater flow rates estimated by the solute mass balance method are sensitive to assumed solute concentrations in discharging groundwater. Pore water samples from the lake bed are shown to be more representative of water discharging to the lake than are samples from piezometers near the lake shore, but spatial and temporal variability in pore water chemistry must be considered. Stable isotope analyses (18O and 2H) of lake water, groundwater, and pore water samples show that water discharging to Nevins Lake in the spring is entirely recycled lake water, and no groundwater derived from terrestrial recharge reaches the lake. The conceptual model formulated during this study linking lake chemistry and the contiguous groundwater system and general groundwater flow patterns surrounding highly transient lake systems are likely

  15. Development and Evaluation of an Ultrasonic Groundwater Seepage Meter

    Science.gov (United States)

    Paulsen, R. J.; Smith, C. F.; O'Rourke, D.; Wong, T.; Bokuniewicz, H.

    2001-05-01

    Submarine groundwater discharge can influence significantly the near-shore transport and flux of chemicals into the oceans. Quantification of the sources and rates of such discharge requires a groundwater seepage meter that provides continuous measurements at high resolution over an extended period of time. An ultrasonic flow meter has been adapted for such measurements in the submarine environment. Connected to a steel collection funnel, the meter houses two piezoelectric transducers mounted at opposite ends of a cylindrical flow tube. By monitoring the perturbations of fluid flow on the propagation of sound waves inside the flow tube, the ultrasonic meter can measure both forward and reverse fluid flows in real time. Laboratory and field calibrations show that the ultrasonic meter can resolve groundwater discharges on the order of 0.1 μ m/s, and it is sufficiently robust for deployment in the field for several days. Data from West Neck Bay, Shelter Island, New York elucidate the temporal and spatial heterogeneity of submarine groundwater discharge and its interplay with tidal loading. A negative correlation between the discharge and tidal elevation was generally observed. A methodology was also developed whereby data for the sound velocity as a function of temperature can be used to infer the salinity and source of the submarine discharge. Independent measurements of electrical conductance were performed to validate this methodology. This meter has also been deployed as part of an international groundwater seepage intercomparison experiment with Scientific Committee on Oceanic Research (SCOR) / Land-Ocean Interaction in the Coastal Zone (LOICZ) Working Group 112. Results are in good agreement with other methodologies developed to quantify submarine groundwater discharge.

  16. CHARACTERISTICS OF HYDROCARBON EXPLOITATION IN ARCTIC CIRCLE

    Directory of Open Access Journals (Sweden)

    Vanja Lež

    2013-12-01

    Full Text Available The existence of large quantities of hydrocarbons is supposed within the Arctic Circle. Assumed quantities are 25% of the total undiscovered hydrocarbon reserves on Earth, mostly natural gas. Over 500 major and minor gas accumulations within the Arctic Circle were discovered so far, but apart from Snøhvit gas field, there is no commercial exploitation of natural gas from these fields. Arctic gas projects are complicated, technically hard to accomplish, and pose a great threat to the return of investment, safety of people and equipment and for the ecosystem. Russia is a country that is closest to the realization of the Arctic gas projects that are based on the giant gas fields. The most extreme weather conditions in the seas around Greenland are the reason why this Arctic region is the least explored and furthest from the realization of any gas project (the paper is published in Croatian .

  17. Gas reservoir evaluation for underbalanced horizontal drilling

    Directory of Open Access Journals (Sweden)

    Li Gao

    2014-01-01

    Full Text Available A set of surface equipment for monitoring the parameters of fluid and pressure while drilling was developed, and mathematical models for gas reservoir seepage and wellbore two-phase flow were established. Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling. Based on the monitored gas production along the well depth, the gas reservoir type could be identified.

  18. Probability distribution functions of turbulence in seepage-affected alluvial channel

    Science.gov (United States)

    Sharma, Anurag; Kumar, Bimlesh

    2017-02-01

    The present experimental study is carried out on the probability distribution functions (PDFs) of turbulent flow characteristics within near-bed-surface and away-from-bed surfaces for both no seepage and seepage flow. Laboratory experiments were conducted in the plane sand bed for no seepage (NS), 10% seepage (10%S) and 15% seepage (15%) cases. The experimental calculation of the PDFs of turbulent parameters such as Reynolds shear stress, velocity fluctuations, and bursting events is compared with theoretical expression obtained by Gram-Charlier (GC)-based exponential distribution. Experimental observations follow the computed PDF distributions for both no seepage and seepage cases. Jensen-Shannon divergence (JSD) method is used to measure the similarity between theoretical and experimental PDFs. The value of JSD for PDFs of velocity fluctuation lies between 0.0005 to 0.003 while the JSD value for PDFs of Reynolds shear stress varies between 0.001 to 0.006. Even with the application of seepage, the PDF distribution of bursting events, sweeps and ejections are well characterized by the exponential distribution of the GC series, except that a slight deflection of inward and outward interactions is observed which may be due to weaker events. The value of JSD for outward and inward interactions ranges from 0.0013 to 0.032, while the JSD value for sweep and ejection events varies between 0.0001 to 0.0025. The theoretical expression for the PDF of turbulent intensity is developed in the present study, which agrees well with the experimental observations and JSD lies between 0.007 and 0.015. The work presented is potentially applicable to the probability distribution of mobile-bed sediments in seepage-affected alluvial channels typically characterized by the various turbulent parameters. The purpose of PDF estimation from experimental data is that it provides a complete numerical description in the areas of turbulent flow either at a single or finite number of points.

  19. Scour Downstream of Grade Control Structures under the Influence of Upward Seepage

    Science.gov (United States)

    Shafai-Bejestan, Mahmood; Nabavi, Seyed Mojtaba Razavi; Dey, Subhasish

    2016-06-01

    The installation of free falling jet grade control structures has become a popular choice for river bed stabilization. However, the formation and development of scour downstream of the structure may lead to failure of the structure itself. The current approaches to scour depth prediction are generally based on studies conducted with the absence of upward seepage. In the present study, the effects of upward seepage on the scour depth were investigated. A total of 78 tests without and with the application of upward seepage were carried out using three different sediment sizes, three different tailwater depths, four different flow discharges, and four different upward seepage flow discharge rates. In some tests, the three-dimensional components of the flow velocity within the scour hole were measured for both the cases with and without upward seepage. The scour depth measured for the no-seepage results compared well with the most accurate relationship found in the literature. It was found that generally the upward seepage reduced the downward velocity components near the bed, which led to a decrease in the maximum scour depth. A maximum scour depth reduction of 49% was found for a minimum tailwater depth, small sediment size, and high flow discharge. A decay of the downward velocity vector within the jet impingement was found due to the upward seepage flow velocity. The well known equation of D'Agostino and Ferro was modified to account for the effect of upward seepage, which satisfactorily predicted the experimental scour depth, with a reasonable average error of 10.7%.

  20. I. Textural/Structural tuning and nanoparticle stabilization of copper-containing nanocomposite materials. II. Generation of reducing agents for automotive exhaust gas purification via the processing of hydrocarbons in a PACT (plasma and catalysis integrated technologies) reactor

    Science.gov (United States)

    Xing, Yu

    This research consists of two parts. The first part deals with the preparation and properties of copper-containing nanocomposite materials. For studies of textural tuning, structural tuning, or material sintering, copper/aluminum and copper/zinc nanocomposites were prepared via various inorganic synthesis methods including conventional coprecipitation methods and a novel urea-gelation/thermal-modification method that produces narrow distributions of pore sizes, high surface areas, and significantly higher specific metal loadings. Solid-solid reaction analysis and differential scanning calorimetry (DSC) analysis were developed for the determination of the mixing homogeneities of the copper/aluminum nanocomposites. A sintering experiment at 250-600°C for 350 h under methanol-steam reforming conditions was carried out to compare the stability of supported Cu0 nanoparticles. The mixing homogeneities of CuO/Al2O3 nanocomposites significantly affected the thermal stability of their reduced Cu0 crystallites. Creation of relatively narrow distributions of pore sizes with relatively small major pore diameters (e.g., 3.5 nm) can also be used for the stabilization of supported Cu0 nanoparticles. The supported nanoparticles with a relatively small initial size cannot ensure good thermal stability. A "hereditary" character on the homogeneity of copper/aluminum nanocomposites was revealed. Stepwise reduction and reoxidation were studied for the structural tuning and purification of Cu-Al-O spinels with isotropic and gradual unit-cell contractions. The second part of the research deals with the processing of hydrocarbons. Conversion of a model hydrocarbon (n-hexane or n-octane) in an AC discharge PACT (plasma and catalysis integrated technologies) reactor was verified to be an effective method to instantly produce reducing agents (e.g., hydrogen or/and light alkanes and alkenes), at room temperature and atmospheric pressure for automotive exhaust gas purification. Effects of

  1. INFLUENCE OF SEEPAGE FACE OBLIQUITY ON DISCHARGE OF GROUNDWATER AND ITS POLLUTANT INTO LAKE FROM A TYPICAL UNCONFINED AQUIFER

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lab experiment and mathematical simulation Modular three dimensional finite difference groundwater (MODFLOW) were performed in a soil tank to simulate the hydrogeochemical interaction between lake and typical unconfined aquifer. Results show that the velocity decreases exponentially with the transect distance on seepage face. The maximal velocity occurs at the top point of seepage face. The obliquity of seepage face has a great influence on the maximum and distribution of seepage velocity. With the increase of the obliquity of seepage face, the maximal velocity decreases quickly and the velocity distribution becomes much more even. Most of groundwater flow and pollutant flux discharges through a narrow portion near the top of seepage face. The flow and mass concentrated in the narrow portion increase with the decrease of the obliquity of seepage face. These will benefit to design a reasonable and economical scenario to manage lakeshore and to control the pollution of lake water near lakeshore.

  2. Occupational exposure to polycyclic aromatic hydrocarbons in airborne particulate matter: validation and application of a gas chromatography-mass spectrometry analytical method.

    Science.gov (United States)

    Fioretti, Marzia; Catrambone, Tamara; Gordiani, Andrea; Cabella, Renato

    2010-12-01

    This study concerns the validation of an analytical method for the measurement of occupational exposure to trace levels of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter (APM). Personal exposure to selected PAHs of five workers occupationally exposed to urban pollution in Rome, Italy, was evaluated. The samples were collected over 10 days evenly distributed during winter and summer of 2008. Polycyclic aromatic hydrocarbons were collected by a sampling pump and trapped in polytetrafluoroethylene filters; ultrasonic extraction was applied to extract PAH species from the matrix with toluene, and the concentrated extract was quantitatively analyzed by GC/MS. The analytical method was optimized and validated using a standard reference material of urban dust (SRM 1649a). Detection limits ranged from 0.8 ng per sample for indeno [1,2,3-cd] pyrene to 20.4 ng for sample for anthracene. Experimental results of the 50 personal samples collected showed that phenanthrene was the predominant polycyclic aromatic hydrocarbon [95% CI (32.42-41.13 ng m(-3))]; the highest benzo[a]pyrene concentration was 2.58 ng m(-3), approximately 2-fold higher than European annual target values (1 ng m(-3)). Seasonal variations of personal exposure to selected PAHs suggested higher emissions and reduced atmospheric reactivity of PAH compounds in winter. The analytical method was a suitable procedure for the determination of 13 of the 16 priority PAHs in APM personal samples and can be considered a useful tool to evaluate occupational exposure to low PAH levels.

  3. Methylotrophic bacteria symbiosis with the higher plants as means of minimization of the lower hydrocarbons concentration during artificial ecosystem gas exchange

    Science.gov (United States)

    Berkovich, Yuliy; Smolyanina, Svetlana; Moukhamedieva, Lana; Mardanov, Robert; Doronina, Nina; Ivanova, Ekaterina

    Plant growth unit should be included in the LSS for the space vehicles for vitamin greens supply and psychological support of cosmonauts during long-term missions. The lower hydrocarbons such as methane, methanol, methylated sulfuric compounds and methylated amines, ethylene and so on, are the natural products of human and plant metabolism and usually considered as the air pollutions. It is shown, that one way to decrease the lower hydrocarbons concentration in the artificial ecosystems could be colonization of the plants by methylotrophic bacteria. The aerobic methylotrophic bacteria possess unique ability to use methane and its oxidized or replaced derivatives without food damage and human, animals or plants infection. We have found that methylotrophic bacteria are the phyto-symbiotic bacteria: they stimulate growth and development of the colonized plants because of synthesizing cytokinins and auxins, and vitamin B12.Two collection strains of the obligate methylotrophic bacteria - Methylovorus mays C and Methylomonas metanica S - were chosen because of their high activity to assimilate the lower hydrocarbons due to functioning of methanoldehydrogenase, methanmonooxigenase and ribulose monophosphate cycle enzymes system.Colonization of the leaf cabbage Brassica chinensis L. by these strains led to approximately 30 % reduce of methanol and methane concentration in the air inside phytotron. Experimental estimations of the influence of methylotrophic bacteria on leafy greens growth and development are obtained.

  4. Final technology report for D-Area oil seepage basin bioventing optimization test, environmental restoration support

    Energy Technology Data Exchange (ETDEWEB)

    Radway, J.C.; Lombard, K.H.; Hazen, T.C.

    1997-01-24

    One method proposed for the cleanup of the D-Area Oil Seepage Basin was in situ bioremediation (bioventing), involving the introduction of air and gaseous nutrients to stimulate contaminant degradation by naturally occurring microorganisms. To test the feasibility of this approach, a bioventing system was installed at the site for use in optimization testing by the Environmental Biotechnology Section of the Savannah River Technology Center. During the interim action, two horizontal wells for a bioventing remediation system were installed eight feet below average basin grade. Nine piezometers were also installed. In September of 1996, a generator, regenerative blower, gas cylinder station, and associated piping and nutrient injection equipment were installed at the site and testing was begun. After baseline characterization of microbial activity and contaminant degradation at the site was completed, four injection campaigns were carried out. These consisted of (1) air alone, (2) air plus triethylphosphate (TEP), (3) air plus nitrous oxide, and (4) air plus methane. This report describes results of these tests, together with conclusions and recommendations for further remediation of the site. Natural biodegradation rates are high. Oxygen, carbon dioxide, and methane levels in soil gas indicate substantial levels of baseline microbial activity. Oxygen is used by indigenous microbes for biodegradation of organics via respiration and hence is depleted in the soil gas and water from areas with high contamination. Carbon dioxide is elevated in contaminated areas. High concentrations of methane, which is produced by microbes via fermentation once the oxygen has been depleted, are found at the most contaminated areas of this site. Groundwater measurements also indicated that substantial levels of natural contaminant biodegradation occurred prior to air injection.

  5. Methane Fluxes to the Atmosphere from Perennial Hydrocarbon Plumes in the Northern Gulf of Mexico

    Science.gov (United States)

    Solomon, E.; Kastner, M.; MacDonald, I.

    2006-12-01

    Methane is a radiatively important trace gas in the atmosphere playing a significant role in greenhouse warming and ozone destruction. The current atmospheric methane budget, however, is still clouded by large uncertainties in the individual source strengths. Estimates of the flux of methane from the ocean to the atmosphere range from 5-15 Tg/yr, but do not include seafloor methane seepage. The large uncertainty in the magnitude of this flux emphasizes the importance of better constraining the spatial and temporal variations in marine methane emissions. Improved constraints on the natural input of methane from the oceans will enable better estimates of changes in anthropogenic inputs over time and their contribution to global climate change. The northern Gulf of Mexico (GOM) contains prolific seafloor gas vents, oil seeps, and gas hydrate deposits. During two research expeditions in the GOM in 2002 and 2003, methane concentrations and carbon isotopic ratios were measured within the water column by a novel experiment in which bubble plumes from 5 seafloor seeps and one mud volcano were sampled with an ascending submersible from the seafloor to the sea surface. Traditionally, CTD casts have been used to sample methane in the water column, which, because of currents, at best only meander through these relatively narrow plumes. Based on δ13C-DIC values of pore waters extracted from push cores at the seeps, methane is not consumed by anaerobic oxidation in the sediment column, thus all of the methane advecting from depth enters the water column. The δ13C of the bottom water methane ranges from -54.38 to -45.91‰, indicating most of it is thermogenic in origin. The gas bubbles also contain C2-C4 hydrocarbons and are coated with oil, which inhibits methane oxidation and bubble dissolution during ascent. This is observed in the only slight increase in δ13C- CH4 to the surface within the plumes. Surface waters have an average δ13C-CH4 of - 47.00‰, thus using an

  6. Investigation of shallow gas hydrate occurrence and gas seep activity on the Sakhalin continental slope, Russia

    Science.gov (United States)

    Jin, Young Keun; Baranov, Boris; Obzhirov, Anatoly; Salomatin, Alexander; Derkachev, Alexander; Hachikubo, Akihiro; Minami, Hrotsugu; Kuk Hong, Jong

    2016-04-01

    The Sakhalin continental slope has been a well-known gas hydrate area since the first finding of gas hydrate in 1980's. This area belongs to the southernmost glacial sea in the northern hemisphere where most of the area sea is covered by sea ice the winter season. Very high organic carbon content in the sediment, cold sea environment, and active tectonic regime in the Sakhalin slope provide a very favorable condition for occurring shallow gas hydrate accumulation and gas emission phenomena. Research expeditions under the framework of a Korean-Russian-Japanese long-term international collaboration projects (CHAOS, SSGH-I, SSGH-II projects) have been conducted to investigate gas hydrate occurrence and gas seepage activities on the Sakhalin continental slope, Russia from 2003 to 2015. During the expeditions, near-surface gas hydrate samples at more than 30 sites have been retrieved and hundreds of active gas seepage structures on the seafloor were newly registered by multidisciplinary surveys. The gas hydrates occurrence at the various water depths from about 300 m to 1000 m in the study area were accompanied by active gas seepage-related phenomena in the sub-bottom, on the seafloor, and in the water column: well-defined upward gas migration structures (gas chimney) imaged by high-resolution seismic, hydroacoustic anomalies of gas emissions (gas flares) detected by echosounders, seafloor high backscatter intensities (seepage structures) imaged by side-scan sonar and bathymetric structures (pockmarks and mounds) mapped by single/multi-beam surveys, and very shallow SMTZ (sulphate-methane transition zone) depths, strong microbial activities and high methane concentrations measured in sediment/seawater samples. The highlights of the expeditions are shallow gas hydrate occurrences around 300 m in the water depth which is nearly closed to the upper boundary of gas hydrate stability zone in the area and a 2,000 m-high gas flare emitted from the deep seafloor.

  7. Cruise summary for P-1-02-SC: acoustic imaging of natural oil and gas seeps and measurement of dissolved methane concentration in coastal waters near Pt. Conception, California

    Science.gov (United States)

    Lorenson, T.D.; Dougherty, Jennifer A.; Ussler, William; Paull, Charles K.

    2003-01-01

    Water-column acoustic anomalies and methane concentrations were documented in coastal waters surrounding Pt. Conception, California, in March 2002. The purpose of this survey, supported by the Minerals Management Service, was to locate active oil and gas seeps in the area as a background for further studies to determine hydrocarbon flux, mainly oil, into the environment. Objectives in reaching this goal are to (1) document the locations and geochemically fingerprint natural seeps within the offshore southern Santa Maria Basin; (2) geochemically fingerprint coastal tar residues and potential sources, both onshore and offshore, in this region; (3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; (4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; (5) attempt to predict transport pathways of oil from seep sources to the coastline and; (6) interpret the petroleum system history for the natural seeps. This survey, addressing objective 1, focused on the area from offshore Surf Beach to the north and Gaviota to the south in water depths ranging from 20 to 500m. In addition, nine stations were sampled outside this area to provide a regional context. Water-column methane concentrations were measured in water samples collected from the R/V Point Sur with Niskin bottles from various depths. A total of 724 water samples from 94 stations were collected.

  8. HYDROCARBONS RESERVES IN VENEZUELA

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Cruz, D.J.

    2007-07-01

    Venezuela is an important player in the energy world, because of its hydrocarbons reserves. The process for calculating oil and associated gas reserves is described bearing in mind that 90% of the gas reserves of Venezuela are associated to oil. Likewise, an analysis is made of the oil reserves figures from 1975 to 2003. Reference is also made to inconsistencies found by international experts and the explanations offered in this respect by the Ministry of Energy and Petroleum (MENPET) and Petroleos de Venezuela (PDVSA) regarding the changes that took place in the 1980s. In turn, Hubbert's Law is explained to determine peak production of conventional oil that a reservoir or field will reach, as well as its relationship with remaining reserves. Emphasis is placed on the interest of the United Nations on this topic. The reserves of associated gas are presented along with their relationship with the different crude oils that are produced and with injected gas, as well as with respect to the possible changes that would take place in the latter if oil reserves are revised. Some recommendations are submitted so that the MENPET starts preparing the pertinent policies ruling reserves. (auth)

  9. Incorporating seepage losses into a 1D unsteady model of floods in ...

    African Journals Online (AJOL)

    2015-07-04

    Joseph et al., 2004): (i) runoff volume and velocity; (ii) channel geometry; (iii) ... of seepage on different turbulent characteristics for an open channel flow. ..... Comparison of flow profiles calculated by present model with MIKE 11.

  10. NUMERICAL ANALYSIS OF SATURATED-UNSATURATED SEEPAGE FLOW IN FRACTURED ROCK MASS DUE TO SURFACE INFILTRATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seepage flow in fractured rock mass due to surface infiltration is a saturated-unsaturated seepage process. Aimed at rock mass with large fracture density, which can be equivalent to continuum, a mathematical model for saturated-unsaturated seepage flow in fractured rock mass due to surface infiltration was established in this paper. The Galerkin finite element method was used in numerical simulation and a finite element program used to calculate saturated-unsaturated seepage flow due to surface infiltration was worked out. A model experiment was employed examine the reasonableness of the program. The results show that the proposed model and program are reasonable. The application of the analysis method in this paper in an engineering project shows that the method is reliable and feasible.

  11. Is Terzaghi’s effective stress a stress variable under seepage conditions?

    Institute of Scientific and Technical Information of China (English)

    雷国辉; 赵仲辉; 吴宏伟

    2015-01-01

    From the continuum mechanics perspective, an attempt was made to clarify the role of Terzaghi’s effective stress in the theoretical analysis of saturated soil subjected to seepage. The necessity of performing a coupled hydromechanical analysis to solve the seepage−deformation interaction problem was illustrated by examining the equations of static equilibrium among the effective stress, seepage force, pore-water pressure and total stress. The conceptual definition of stress variable that satisfies the principles of continuum mechanics is applied in the coupled hydromechanical analysis. It is shown that Terzaghi’s effective stress is in fact not a stress variable under seepage conditions, and the seepage force acting on the soil skeleton cannot be viewed as a body force. This offers a clue to the underlying cause of a paradox between the real Pascal’s hydrostatic state and the hydrostatic state predicted by a class of continuum hydromechanical theories.

  12. ANALYSIS OF SEEPAGE FLOW IN A CONFINED AQUIFER WITH A STANDING COLUMN WELL

    Institute of Scientific and Technical Information of China (English)

    LI Min; DIAO Nai-ren; FANG Zhao-hong

    2007-01-01

    The standing column well for ground source heat pump systems is a promising technology with high efficiency and environmental benefit, where groundwater is drawn from the bottom of a well and then re-injected to its top after transferring heat with heat pumps. Heat transfer analysis of great significance and aquifer involves complex problems. Determining the groundwater seepage flow is a precondition to solve the energy equation describing the heat transfer of the system. Only when piezometric head is obtained, the seepage velocity can be determined according to Darcy's law. In this article the groundwater seepage flow in an axial symmetrical geometry was studied under the assumption that gross groundwater flow is neglected. An analytical solution of the groundwater seepage flow for a confined aquifer was acquired by using the integral transform method, which may provide a foundation for heat transfer analysis of the standing column well system.

  13. Preliminary Geospatial Analysis of Arctic Ocean Hydrocarbon Resources

    Energy Technology Data Exchange (ETDEWEB)

    Long, Philip E.; Wurstner, Signe K.; Sullivan, E. C.; Schaef, Herbert T.; Bradley, Donald J.

    2008-10-01

    Ice coverage of the Arctic Ocean is predicted to become thinner and to cover less area with time. The combination of more ice-free waters for exploration and navigation, along with increasing demand for hydrocarbons and improvements in technologies for the discovery and exploitation of new hydrocarbon resources have focused attention on the hydrocarbon potential of the Arctic Basin and its margins. The purpose of this document is to 1) summarize results of a review of published hydrocarbon resources in the Arctic, including both conventional oil and gas and methane hydrates and 2) develop a set of digital maps of the hydrocarbon potential of the Arctic Ocean. These maps can be combined with predictions of ice-free areas to enable estimates of the likely regions and sequence of hydrocarbon production development in the Arctic. In this report, conventional oil and gas resources are explicitly linked with potential gas hydrate resources. This has not been attempted previously and is particularly powerful as the likelihood of gas production from marine gas hydrates increases. Available or planned infrastructure, such as pipelines, combined with the geospatial distribution of hydrocarbons is a very strong determinant of the temporal-spatial development of Arctic hydrocarbon resources. Significant unknowns decrease the certainty of predictions for development of hydrocarbon resources. These include: 1) Areas in the Russian Arctic that are poorly mapped, 2) Disputed ownership: primarily the Lomonosov Ridge, 3) Lack of detailed information on gas hydrate distribution, and 4) Technical risk associated with the ability to extract methane gas from gas hydrates. Logistics may control areas of exploration more than hydrocarbon potential. Accessibility, established ownership, and leasing of exploration blocks may trump quality of source rock, reservoir, and size of target. With this in mind, the main areas that are likely to be explored first are the Bering Strait and Chukchi

  14. Comparative Analysis of Seepage Losses From Nighttime Water Level Changes and Water Balance Methods

    Science.gov (United States)

    Shukla, A.; Shukla, S.; Wu, C.

    2013-12-01

    Several techniques including Darcy's theory of one and two dimensional groundwater flow, seepage meters, and water balance have been used in the past to estimate seepage from impoundments such as reservoirs, ponds, and constructed wetlands. These methods result in varying level of errors in seepage estimates depending on method and biogeophysical setting to which they are applied. In this study, we explore a simple yet effective method of estimating groundwater fluxes for two stormwater impoundments (SIs) and a partially drained wetland located in agricultural areas using diurnal changes in surface water levels inside these systems. Days with no inflow, outflow, and rainfall were selected to minimize the effect of the error associated water balance components on seepage estimation. Difference in water levels between 20:00 hrs and 5:00 hrs was calculated for the selected days. Only nighttime change was considered keeping in mind the fact that evapotranspiration is negligible during night and hence, the change in water levels can be attributed to seepage alone. Seepage from the analysis of night-time change in the water levels was compared to the estimates from the water balance method with seepage being the residual component of the balance. Results show that seepage constitutes a large part of total outflow from the impoundments (29% and 17% for SI1 during 2008-2009 and 2009-2010 respectively, 30% for SI2 during 2009-2010 and seepage was greater than the total surface water outflow from SI2 during 2010-2011). Accuracy of this method varied from 5% to 41% for first and 4% to 29% for the second SI. Considering that errors as high as 100% have been reported with the use of Darcy's approach, the errors from our method are lower. The lower errors combined with ease of application without using the hydraulic conductivity values makes our approach feasible for other similar systems. Improved seepage estimate from the proposed method will result in quantification of

  15. Calcareous forest seepages acting as biodiversity hotspots and refugia for woodland snail faunas

    Science.gov (United States)

    Horsák, Michal; Tajovská, Eva; Horsáková, Veronika

    2017-07-01

    Land-snail species richness has repeatedly been found to increase with the increasing site calcium content and humidity. These two factors, reported as the main drivers of land-snail assemblage diversity, are also among the main habitat characteristics of calcareous seepages. Here we explore local species richness and compositional variation of forest spring-fed patches (i.e. seepages), to test the hypothesis that these habitats might act as biodiversity hotspots and refugia of regional snail faunas. In contrast to treeless spring fens, only little is known about land snail faunas inhabiting forest seepages. Studying 25 isolated calcareous forest seepages, evenly distributed across the White Carpathians Protected Landscape Area (SE Czech Republic), we found that these sites, albeit spatially very limited, can harbour up to 66% of the shelled land-snail species known to occur in this well-explored protected area (in total 83 species). By comparing land snail assemblages of the studied seepages with those occurring in the woodland surroundings of each site as well as those previously sampled in 28 preserved forest sites within the study area, we found the seepages to be among the most species rich sites. Although the numbers of species did not statistically differ among these three systems, we found highly significant differences in species composition. Seepage faunas were composed of many species significantly associated with spring sites, in contrast to the assemblages of both surrounding and preserved forest sites. Our results highly support the hypothesis that calcareous forest seepages might serve as refugia and biodiversity hotspots of regional land snail faunas. Protection of these unique habitats challenges both conservation plans and forest management guidelines as they might act as sources for the recolonization and restoration of forest snail assemblages particularly in areas impoverished by harvesting and clearcutting.

  16. Accelerating Oil and Gas Exploration in Western China by Studies of Formations of Hydrocarbon Accumulations in Superimposed Basins——A Preface

    Institute of Scientific and Technical Information of China (English)

    PANG Xiongqi

    2010-01-01

    @@ The superimposed basins in the western region of China are a hot research topic for earth scientists home and abroad for their vast area and rich oil and gas resources.Their complex geological conditions and resultant great exploration difficulties have received much attention of the scientists.This issue presents the advances of several scholars in their long-term research on the mechanisms of oil and gas accumulation and the patterns of oil and gas distribution.These studies are part of the National 973Project entitled"Mechanism of Oil and Gas Accumulation and Patterns of Oil and Gas Distribution in Typical Superimposed Basins in the Western Region of China(no.2006CB202300)",which is funded by the Chinese Ministry of Science and Technology.

  17. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    Energy Technology Data Exchange (ETDEWEB)

    E. Sonnenthale

    2001-04-16

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M&O) 2000 [1534471]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M&O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: Performance Assessment (PA); Near-Field Environment (NFE) PMR; Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); and UZ Flow and Transport Process Model Report (PMR). The work scope for this activity is presented in the TWPs cited above, and summarized as follows: Continue development of the repository drift-scale THC seepage model used in support of the TSPA in-drift geochemical model; incorporate heterogeneous fracture property realizations; study sensitivity of results to changes in input data and mineral assemblage; validate the DST model by comparison with field data; perform simulations to predict mineral dissolution and precipitation and their effects on fracture properties and chemistry of water (but not flow rates) that may seep into drifts; submit modeling results to the TDMS and document the models. The model development, input data, sensitivity and validation

  18. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    Energy Technology Data Exchange (ETDEWEB)

    E. Gonnenthal; N. Spyoher

    2001-02-05

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) 2000 [153447]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M and O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC se