WorldWideScience

Sample records for hydrocarbon gas formation

  1. 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.

  2. 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....

  3. 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....

  4. 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.

  5. 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).

  6. 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.)

  7. Formation of hydrocarbons by bacteria and algae

    Energy Technology Data Exchange (ETDEWEB)

    Tornabene, T.G.

    1980-12-01

    A literature review has been performed summarizing studies on hydrocarbon synthesis by microorganisms. Certain algal and bacterial species produce hydrocarbons in large quantities, 70 to 80% of dry cell mass, when in a controlled environment. The nutritional requirements of these organisms are simple: CO/sub 2/ and mineral salts. The studies were initiated to determine whether or not microorganisms played a role in petroleum formation. 90 references. (DMC)

  8. 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.

  9. 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.

  10. Creating and maintaining a gas cap in tar sands formations

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX); Dinkoruk, Deniz Sumnu (Houston, TX); Wellington, Scott Lee (Bellaire, TX)

    2010-03-16

    Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

  11. 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.

  12. Methane Decomposition and C2 Hydrocarbon Formation under the Condition of DC Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    Jianxun He; Miao Hu; Zhiguo Lu

    2004-01-01

    The infrared emission spectra of methane, H, CH and C2 hydrocarbons in natural gas were measured. The processes of methane decomposition and formation of C2 hydrocarbons were studied. The experiment shows that methane decomposition can be divided into three periods as the reaction proceeds.In the first period, a large number of free radicals were formed. While in the last period, the formation of C2 hydrocarbons and the decrease of free radicals were observed. The time and conditions of methane decomposition and formation of C2 hydrocarbons are different.

  13. 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.

  14. 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.

  15. 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.

  16. Deposit formation in hydrocarbon rocket fuels

    Science.gov (United States)

    Roback, R.; Szetela, E. J.; Spadaccini, L. J.

    1981-01-01

    An experimental program was conducted to study deposit formation in hydrocarbon fuels under flow conditions that exist in high-pressure, rocket engine cooling systems. A high pressure fuel coking test apparatus was designed and developed and was used to evaluate thermal decomposition (coking) limits and carbon deposition rates in heated copper tubes for two hydrocarbon rocket fuels, RP-1 and commercial-grade propane. Tests were also conducted using JP-7 and chemically-pure propane as being representative of more refined cuts of the baseline fuels. A parametric evaluation of fuel thermal stability was performed at pressures of 136 atm to 340 atm, bulk fuel velocities in the range 6 to 30 m/sec, and tube wall temperatures in the range 422 to 811 K. Results indicated that substantial deposit formation occurs with RP-1 fuel at wall temperatures between 600 and 800 K, with peak deposit formation occurring near 700 K. No improvements were obtained when deoxygenated JP-7 fuel was substituted for RP-1. The carbon deposition rates for the propane fuels were generally higher than those obtained for either of the kerosene fuels at any given wall temperature. There appeared to be little difference between commercial-grade and chemically-pure propane with regard to type and quantity of deposit. Results of tests conducted with RP-1 indicated that the rate of deposit formation increased slightly with pressure over the range 136 atm to 340 atm. Finally, lating the inside wall of the tubes with nickel was found to significantly reduce carbon deposition rates for RP-1 fuel.

  17. Cogeneration systems and processes for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; Fowler, Thomas David; Karanikas, John Michael

    2009-12-29

    A system for treating a hydrocarbon containing formation includes a steam and electricity cogeneration facility. At least one injection well is located in a first portion of the formation. The injection well provides steam from the steam and electricity cogeneration facility to the first portion of the formation. At least one production well is located in the first portion of the formation. The production well in the first portion produces first hydrocarbons. At least one electrical heater is located in a second portion of the formation. At least one of the electrical heaters is powered by electricity from the steam and electricity cogeneration facility. At least one production well is located in the second portion of the formation. The production well in the second portion produces second hydrocarbons. The steam and electricity cogeneration facility uses the first hydrocarbons and/or the second hydrocarbons to generate electricity.

  18. Mechanism of Silurian Hydrocarbon Pool Formation in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    Liu Luofu; Guo Yongqiang; Zhao Yande; Li Yan; Chen Yuanzhuang; Chen Lixin; Pang Xiongqi; Xie Qilai; Huo Hong; Zhao Suping; Li Chao; Li Shuangwen

    2007-01-01

    There are three formation stages of Silurian hydrocarbon pools in the Tarim Basin. The widely distributed asphaltic sandstones in the Tazhong (central Tarim) and Tabei (northern Tarim) areas are the results of destruction of hydrocarbon pools formed in the first-stage, and the asphaltic sandstones around the Awati Sag were formed in the second-stage. The hydrocarbon migration characteristics reflected by the residual dry asphalts could represent the migration characteristics of hydrocarbons in the Silurian paleo-pools, while the present movable oil in the Silurian reservoirs is related to the later-stage (the third-stage) hydrocarbon accumulation.

  19. Deposit formation and heat transfer in hydrocarbon rocket fuels

    Science.gov (United States)

    Giovanetti, A. J.; Spadaccini, L. J.; Szetela, E. J.

    1983-01-01

    An experimental research program was undertaken to investigate the thermal stability and heat transfer characteristics of several hydrocarbon fuels under conditions that simulate high-pressure, rocket engine cooling systems. The rates of carbon deposition in heated copper and nickel-plated copper tubes were determined for RP-1, propane, and natural gas using a continuous flow test apparatus which permitted independent variation and evaluation of the effect on deposit formation of wall temperature, fuel pressure, and fuel velocity. In addition, the effects of fuel additives and contaminants, cryogenic fuel temperatures, and extended duration testing with intermittent operation were examined. Parametric tests to map the thermal stability characteristics of RP-1, commercial-grade propane, and natural gas were conducted at pressures of 6.9 to 13.8 MPa, bulk fuel velocities of 30 to 90 m/s, and tube wall temperatures in the range of 230 to 810 K. Also, tests were run in which propane and natural gas fuels were chilled to 230 and 160 K, respectively. Corrosion of the copper tube surface was detected for all fuels tested. Plating the inside of the copper tubes with nickel reduced deposit formation and eliminated tube corrosion in most cases. The lowest rates of carbon deposition were obtained for natural gas, and the highest rates were obtained for propane. For all fuels tested, the forced-convection heat transfer film coefficients were satisfactorily correlated using a Nusselt-Reynolds-Prandtl number equation.

  20. 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

  1. Abiogenic formation of alkanes in the Earth's crust as a minor source for global hydrocarbon reservoirs

    Science.gov (United States)

    Sherwood Lollar, B.; Westgate, T. D.; Ward, J. A.; Slater, G. F.; Lacrampe-Couloume, G.

    2002-04-01

    Natural hydrocarbons are largely formed by the thermal decomposition of organic matter (thermogenesis) or by microbial processes (bacteriogenesis). But the discovery of methane at an East Pacific Rise hydrothermal vent and in other crustal fluids supports the occurrence of an abiogenic source of hydrocarbons. These abiogenic hydrocarbons are generally formed by the reduction of carbon dioxide, a process which is thought to occur during magma cooling and-more commonly-in hydrothermal systems during water-rock interactions, for example involving Fischer-Tropsch reactions and the serpentinization of ultramafic rocks. Suggestions that abiogenic hydrocarbons make a significant contribution to economic hydrocarbon reservoirs have been difficult to resolve, in part owing to uncertainty in the carbon isotopic signatures for abiogenic versus thermogenic hydrocarbons. Here, using carbon and hydrogen isotope analyses of abiogenic methane and higher hydrocarbons in crystalline rocks of the Canadian shield, we show a clear distinction between abiogenic and thermogenic hydrocarbons. The progressive isotopic trends for the series of C1-C4 alkanes indicate that hydrocarbon formation occurs by way of polymerization of methane precursors. Given that these trends are not observed in the isotopic signatures of economic gas reservoirs, we can now rule out the presence of a globally significant abiogenic source of hydrocarbons.

  2. Heating hydrocarbon containing formations in a line drive staged process

    Science.gov (United States)

    Miller, David Scott

    2009-07-21

    Method for treating a hydrocarbon containing formation are described herein. Methods may include providing heat to a first section of the formation with one or more first heaters in the first section. First hydrocarbons may be heated in the first section such that at least some of the first hydrocarbons are mobilized. At least some of the mobilized first hydrocarbons may be produced through a production well located in a second section of the formation. The second section may be located substantially adjacent to the first section. A portion of the second section may be provided some heat from the mobilized first hydrocarbons, but is not conductively heated by heat from the first heaters. Heat may be provided to the second section with one or more second heaters in the second section to further heat the second section.

  3. 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.

  4. 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

  5. Formation Dynamics and Quantitative Prediction of Hydrocarbons of the Superpressure System in the Dongying Sag

    Institute of Scientific and Technical Information of China (English)

    SUI Fenggui; HAO Xuefeng; LIU Qing; ZHUO Qingong; ZHANG Shouchun

    2008-01-01

    Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas: the superpressure closed system,the semi-closed system and the normal pressure open system. Based on the analysis of genesis of superpressure in the superpressure closed system and the rule of hydrocarbon expulsion,it is found that hydrocarbon generation is related to superpressure, which is the main driving factor of hydrocarbon migration. Micro fractures formed by superpressure are the main channels for hydrocarbon migration. There are three dynamic patterns for hydrocarbon expulsion: free water drainage, hydrocarbon accumulation and drainage through micro fissures. In the superpressure closed system, the oil-driving-water process and oil/gas accumulation were completed in lithologic traps by way of such two dynamic patterns as episodic evolution of superpressure systems and episodic pressure release of faults. The oil-bearing capacity of lithologic traps is intimately related to reservoir-forming dynamic force. Quantitative evaluation of dynamic conditions for pool formation can effectively predict the oil-bearing capability of traps.

  6. Polycyclic aromatic hydrocarbon formation under simulated coal seam pyrolysis conditions

    Institute of Scientific and Technical Information of China (English)

    Liu Shuqin; Wang Yuanyuan; Wang Caihong; Bao Pengcheng; Dang Jinli

    2011-01-01

    Coal seam pyrolysis occurs during coal seam fires and during underground coal gasification.This is an important source of polycyclic aromatic hydrocarbon (PAH) emission in China.Pyrolysis in a coal seam was simulated in a tubular furnace.The 16 US Environmental Protection Agency priority controlled PAHs were analyzed by HPLC.The effects of temperature,heating rate,pyrolysis atmosphere,and coal size were investigated.The results indicate that the 3-ring PAHs AcP and AcPy are the main species in the pyrolysis gas.The 2-ring NaP and the 4-ring Pyr are also of concern.Increasing temperature caused the total PAH yield to go through a minimum.The lowest value was obtained at the temperature of 600 ℃ Higher heating rates promote PAH formation,especially formation of the lower molecular weight PAHs.The typical heating rate in a coal seam,5 ℃/min,results in intermediate yields of PAHs.The total PAHs yield in an atmosphere of N2 is about 1.81 times that seen without added N2,which indicates that an air flow through the coal seam accelerates the formation of PAHs.An increase in coal particle size reduces the total PAHs emission but promotes the formation of 5- and 6-ring PAHs.

  7. Experimental Probing on Formation Mechanism of Hydrocarbon in Deep Earth

    Institute of Scientific and Technical Information of China (English)

    Weng Kenan; Xiao Wansheng; Zhang Huizi; Wang Benshan

    1997-01-01

    @@ In order to study the formation mechanism of hydrocarbon in the earth's interior, preliminary experiments on chemical reactions of wax, graphite, siderite with supercritical water have been carried out respectively under the conditions of temperature about 800~1500℃ and pressure approximately above 1 GPa. These reactions can produce a large amount of methane, together with some CO2 and a little other hydrocarbons, indicating that the reactions of carbon-bearing materials with supercritical water is possibly a new formation mechanism of hydrocarbon under the conditions of high temperature and high pressure in deep earth.

  8. Hydrocarbon potential assessment of Ngimbang formation, Rihen field of Northeast Java Basin

    Science.gov (United States)

    Pandito, R. H.; Haris, A.; Zainal, R. M.; Riyanto, A.

    2017-07-01

    The assessment of Ngimbang formation at Rihen field of Northeast Java Basin has been conducted to identify the hydrocarbon potential by analyzing the response of passive seismic on the proven reservoir zone and proposing a tectonic evolution model. In the case of petroleum exploration in Northeast Java basin, the Ngimbang formation cannot be simply overemphasized. East Java Basin has been well known as one of the mature basins producing hydrocarbons in Indonesia. This basin was stratigraphically composed of several formations from the old to the young i.e., the basement, Ngimbang, Kujung, Tuban, Ngerayong, Wonocolo, Kawengan and Lidah formation. All of these formations have proven to become hydrocarbon producer. The Ngrayong formation, which is geologically dominated by channels, has become a production formation. The Kujung formation that has been known with the reef build up has produced more than 102 million barrel of oil. The Ngimbang formation so far has not been comprehensively assessed in term its role as a source rock and a reservoir. In 2013, one exploratory well has been drilled at Ngimbang formation and shown a gas discovery, which is indicated on Drill Stem Test (DST) reading for more than 22 MMSCFD of gas. This discovery opens new prospect in exploring the Ngimbang formation.

  9. Thermal simulation of the formation and evolution of coalbed gas

    Institute of Scientific and Technical Information of China (English)

    DUAN Yi; WU Baoxiang; ZHENG Chaoyang; WANG Chuanyuan

    2005-01-01

    Thermal simulation experiment of gas generation from the peat and the coals were performed using the high temperature and pressure apparatus, at temperature ranging from 336.8-600℃, a pressure of 50MPa and two heating rates of 20℃/h and 2℃/h, and the evolution and formation of coalbed gas components were studied. Results show that for the coals, the gaseous products are mainly composed of hydrocarbon gases. However, for the peat the content of hydrocarbon gases in gaseous products is lower than that of non-hydrocarbon components. In the generated hydrocarbon gases methane is predominant and heavy hydrocarbon gases (C2-5) are present in small amount.Meanwhile, carbon dioxide (CO2) predominates the generated non-hydrocarbon gases, and hydrogen (H2) and sulfurated hydrogen (H2S) are existent in trace amount. It is also observed that temperature is the main factor controlling the evolution of coalbed gas generation. With increasing vitrinite reflectance, methane rapidly increases, CO2 sightly increases, and C2-5 hydrocarbons first increase and then decrease. The peat and Shanxi formation coal have a higher generative potential of coalbed gases than coals and Taiyuan formation coal, respectively, reflecting the effect of the property of organic matter on the characteristics of coalbed gas component generation. In this study, it is found that low heating rate is favorable for the generation of methane, H2and CO2, and the decomposition of C2-5 hydrocarbons. This shows that heating time plays an important controlling role in the generation and evolution of coalbed gases. The results obtained from the simulation experiment in the study of coalbed gases in natural system are also discussed.

  10. Rapid gas hydrate formation process

    Science.gov (United States)

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  11. 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.

  12. Formulating formation mechanism of natural gas hydrates.

    Science.gov (United States)

    Palodkar, Avinash V; Jana, Amiya K

    2017-07-25

    A large amount of energy, perhaps twice the total amount of all other hydrocarbon reserves combined, is trapped within gas hydrate deposits. Despite emerging as a potential energy source for the world over the next several hundred years and one of the key factors in causing future climate change, gas hydrate is poorly known in terms of its formation mechanism. To address this issue, a mathematical formulation is proposed in the form of a model to represent the physical insight into the process of hydrate growth that occurs on the surface and in the irregular nanometer-sized pores of the distributed porous particles. To evaluate the versatility of this rigorous model, the experimental data is used for methane (CH4) and carbon dioxide (CO2) hydrates grown in different porous media with a wide range of considerations.

  13. Chemical reaction and dust formation studies in laboratory hydrocarbon plasmas.

    Science.gov (United States)

    Hippler, Rainer; Majumdar, Abhijit; Thejaswini, H. C.

    Plasma chemical reaction studies with relevance to, e.g., Titan's atmosphere have been per-formed in various laboratory plasmas [1,2]. Chemical reactions in a dielectric barrier discharge at medium pressure of 250-300 mbar have been studied in CH4 /N2 and CH4 /Ar gas mixtures by means of mass spectrometry. The main reaction scheme is production of H2 by fragmenta-tion of CH4 , but also production of larger hydrocarbons like Cn Hm with n up to 10 including formation of different functional CN groups is observed. [1] A. Majumdar and R. Hippler, Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition, Rev. Sci. Instrum. 78, 075103 (2007) [2] H.T. Do, G. Thieme, M. Frühlich, H. Kersten, and R. Hippler, Ion Molecule and Dust Particle Formation in Ar/CH4 , Ar/C2 H2 and Ar/C3 H6 Radio-frequency Plasmas, Contrib. Plasma Phys. 45, No. 5-6, 378-384 (2005)

  14. Formation of porous gas hydrates

    CERN Document Server

    Salamatin, Andrey N

    2015-01-01

    Gas hydrates grown at gas-ice interfaces are examined by electron microscopy and found to have a submicron porous texture. Permeability of the intervening hydrate layers provides the connection between the two counterparts (gas and water molecules) of the clathration reaction and makes further hydrate formation possible. The study is focused on phenomenological description of principal stages and rate-limiting processes that control the kinetics of the porous gas hydrate crystal growth from ice powders. Although the detailed physical mechanisms involved in the porous hydrate formation still are not fully understood, the initial stage of hydrate film spreading over the ice surface should be distinguished from the subsequent stage which is presumably limited by the clathration reaction at the ice-hydrate interface and develops after the ice grain coating is finished. The model reveals a time dependence of the reaction degree essentially different from that when the rate-limiting step of the hydrate formation at...

  15. Lithological architecture, geological processes and energy-field environments are major factors for the formation of hydrocarbon reservoirs

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; WANG Zecheng; LI Xiaoqing; WANG Hongjun; WANG Zhaoyun

    2005-01-01

    The formation of hydrocarbon reservoirs is controlled by three major factors: lithological architecture, geological processes and energy-field environments. Among the three major factors, lithological architecture provides the storing medium for hydrocarbon; geological processes include hydrocarbon generation, migration, accumulation, preservation and modification; and energy-field environments refer to the various geothermal and geodynamic forces that affect the lithological architecture and drive the geological processes.In this study, we take Kela-2 and Sulige gas reservoirs as two examples to study relationships among the three major factors, and explain how these factors influence the scale and quality of hydrocarbon reservoirs.

  16. HYDROCARBON FORMATION ON POLYMER-SUPPORTED COBALT

    Energy Technology Data Exchange (ETDEWEB)

    Benner, Linda S.; Perkins, Patrick; Vollhardt, K.Peter C.

    1980-10-01

    In this report we detail the synthesis catalytic chemistry of polystyrene supported {eta}{sup 5} ~cyclopentadienyl- dicarbonyl cobalt, CpCo(CO){sub 2}. This material is active in the hydrogenation of CO to saturated linear hydrocarbons and appears to retain its "homogeneous", mononuclear character during the course of its catalysis, During ·the course of our work 18% and 20% crosslinked analogs of polystyrene supported CpCo(CO){sub 2} were shown to exhibit limited catalytic activity and no CO activation.

  17. Irregular spacing of heat sources for treating hydrocarbon containing formations

    Science.gov (United States)

    Miller, David Scott [Katy, TX; Uwechue, Uzo Philip [Houston, TX

    2012-06-12

    A method for treating a hydrocarbon containing formation includes providing heat input to a first section of the formation from one or more heat sources located in the first section. Fluids are produced from the first section through a production well located at or near the center of the first section. The heat sources are configured such that the average heat input per volume of formation in the first section increases with distance from the production well.

  18. Star formation and gas supply

    Science.gov (United States)

    Catinella, B.

    2016-06-01

    A detailed knowledge of how gas cycles in and around galaxies, and how it depends on galaxy properties such as stellar mass and star formation rate, is crucial to understand galaxy formation and evolution. We take advantage of the most sensitive surveys of cold gas in massive galaxies, GASS and COLD GASS, as well as of the state-of-the-art HI blind survey ALFALFA to investigate how molecular and atomic hydrogen reservoirs vary along and across the main sequence of star-forming galaxies.

  19. 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

  20. 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

    groundwater (P(CH4) = ∼1 atmosphere) and elevated [Cl] and [Ba]. These data suggest that 4He is dominated by an exogenous (i.e., migrated) crustal source for these hydrocarbon gas- and salt-rich fluids. In combination with published inorganic geochemistry (e.g., 87Sr/86Sr, Sr/Ba, Br-/Cl-), new noble gas and hydrocarbon isotopic data (e.g., 20Ne/36Ar, C2+/C1, δ13C-CH4) suggest that a hydrocarbon-rich brine likely migrated from the Marcellus Formation (via primary hydrocarbon migration) as a dual-phase fluid (gas + liquid) and was fractionated by solubility partitioning during fluid migration and emplacement into conventional UD traps (via secondary hydrocarbon migration). Based on the highly fractionated 4He/CH4 data relative to Marcellus and UD production gases, we propose an additional phase of hydrocarbon gas migration where natural gas previously emplaced in UD hydrocarbon traps actively diffuses out into and equilibrates with modern shallow groundwater (via tertiary hydrocarbon migration) following uplift, denudation, and neotectonic fracturing. These data suggest that by integrating noble gas geochemistry with hydrocarbon and dissolved ion chemistry, one can better determine the source and migration processes of natural gas in the Earth's crust, which are two critical factors for understanding the presence of hydrocarbon gases in shallow aquifers.

  1. Experimental Study on Hydrocarbon Formation Due to Reactions Between Carbonates and Water or Water—Bearing Minerals in Deep Earth

    Institute of Scientific and Technical Information of China (English)

    翁克难; 汪本善; 等

    1999-01-01

    In order to investigate the mechanism of formation of abiogenetic hydrocarbons at the depth of the Earth,experimental research on reactions between carbonates and water or waterbearing minerals was carried out at the pressure of about 1GPa and the temperature range of 800-1500℃.The reactions took place in an open and nonequilibrium state.Chromatographic analyses of the gas products indicate that in the experiments there were generated CH4-dominated hydrocarbons,along with some CO2 and CO.Accordingly,we think there is no essential distinction between free-state water and hydroxy in the minerals in the process of hydrocarbon formation.This study indicates that reactions between carbonates and water or water-bearing minerals should be an important factor leading to the formation of abiogenetic hydrocarbons at the Earth's depth.

  2. Duration of the hydrocarbon fluid formation under thermobaric conditions of the Earth's upper mantle

    Science.gov (United States)

    Mukhina, Elena; Kolesnikov, Anton; Kutcherov, Vladimir

    2016-04-01

    Deep abiogenic formation of hydrocarbons is an inherent part of the Earth's global carbon cycle. It was experimentally confirmed that natural gas could be formed from inorganic carbon and hydrogen containing minerals at pressure and temperature corresponding to the Earth's upper mantle conditions. Reaction between calcite, wustite and water in the large volume device was studied in several works. It was previously proposed that reaction is possible only after 40 minutes of exposure at high pressure and temperature. In this work similar experiment at P = 60 kbar and T = 1200 K were carried out in "Toroid" type chamber with the 5 seconds duration of thermobaric exposure. Gas chromatographic analysis of the reaction products has shown the presence of hydrocarbon mixture comparable to 5 minutes and 6 hours exposure experiments. Based on this fact it is possible to conclude that the reaction of natural gas formation is instant at least at given thermobaric conditions. This experiment will help to better understand the process of deep hydrocarbon generation, particularly its kinetics.

  3. Controls on Gas Hydrate Formation and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  4. 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.

  5. Solution mining systems and methods for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; de Rouffignac, Eric Pierre; Schoeling, Lanny Gene

    2009-07-14

    A method for treating an oil shale formation comprising nahcolite is disclosed. The method includes providing a first fluid to a portion of the formation through at least two injection wells. A second fluid is produced from the portion through at least one injection well until at least two injection wells are interconnected such that fluid can flow between the two injection wells. The second fluid includes at least some nahcolite dissolved in the first fluid. The first fluid is injected through one of the interconnected injection wells. The second fluid is produced from at least one of the interconnected injection wells. Heat is provided from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation.

  6. Physical simulation of gas reservoir formation in the Liwan 3-1 deep-water gas field in the Baiyun sag, Pearl River Mouth Basin

    Directory of Open Access Journals (Sweden)

    Gang Gao

    2015-01-01

    Full Text Available To figure out the process and controlling factors of gas reservoir formation in deep-waters, based on an analysis of geological features, source of natural gas and process of reservoir formation in the Liwan 3-1 gas field, physical simulation experiment of the gas reservoir formation process has been performed, consequently, pattern and features of gas reservoir formation in the Baiyun sag has been found out. The results of the experiment show that: ① the formation of the Liwan 3-1 faulted anticline gas field is closely related to the longstanding active large faults, where natural gas is composed of a high proportion of hydrocarbons, a small amount of non-hydrocarbons, and the wet gas generated during highly mature stage shows obvious vertical migration signs; ② liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping & Zhuhai Formation, whereas natural gas comes mainly from source rock of the Enping Formation, and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well; ③ although there was gas migration and accumulation, yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period; later as fault activity gradually weakened, gas started to accumulate into reservoirs in the Baiyun sag; ④ there is stronger vertical migration of oil and gas than lateral migration, and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation; ⑤ effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag; ⑥ the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen, the more likely gas may accumulate in the trap in late stage, therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source

  7. Accounting for water formation from hydrocarbon fuel combustion in life cycle analyses

    Science.gov (United States)

    Belmont, E. L.; Davidson, F. T.; Glazer, Y. R.; Beagle, E. A.; Webber, M. E.

    2017-09-01

    Hydrocarbon fuel production and utilization are considered water intensive processes due to the high volumes of water used in source development and fuel processing. At the same time, there is significant water formed during combustion. However, this water is not currently widely harvested at the site of production. Instead, it is added to the hydrologic cycle, often in a different location from the fuel production site. This study quantifies the water formed from combustion of these fuels and analyzes the magnitudes of formation in the context of other hydrologic sources and sinks in order to facilitate future assessments of water harvesting technology and/or atmospheric impacts of combustion. Annual water formation from stoichiometric combustion of hydrocarbon fuels, including natural gas, oil- and natural gas liquid-derived products, and coal, in the United States and worldwide are presented and compared with quantities of water sequestered, evaporated, and stored in the atmosphere. Water production factors in terms of mass and energy of fuel consumed, WPFm and WPFe, respectively, are defined for the comparison of fuels and incorporation into future life cycle analyses (LCAs). Results show that water formation from combustion has increased worldwide from 2005 to 2015, with the largest increase coming from growth in combustion of natural gas. Water formation from combustion of hydrocarbon fuels equals or exceeds water sequestered from the hydrologic cycle through deep well injection in the US annually. Overall, water formation is deemed significant enough to warrant consideration by LCAs of water intensity in fuel production and use, and should be included in future analyses.

  8. 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...

  9. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  10. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  11. Gas geochemistry characteristic of shale gas in Longmaxi Formation, SE Sichuan Basin, China

    Science.gov (United States)

    Cao, Chunhui; Du, Li; Li, Liwu; He, Jian; Li, Zhongping

    2017-01-01

    Shale gas samples collected from Lower Silurian Longmaxi Formation of Southern Sichuan Basin in Weiyuan were analysed for stable isotope composition of noble gases and molecular composition, stable carbon isotope composition of hydrocarbons. Results show these shale gases are of organic origin gas, and produced at high-over maturity stage. All the analysed hydrocarbon gases reveal complete inversed isotopic trends from methane to propane, and δ13C1, δ13C2 have obviously different between Weiyuan and Changning areas. CO2 was mainly generated during thermogenic processes of transformation of organic matter, although some gases can contain components from endogenic processes and from thermal destruction of carbonates. He and Ar are mainly product of α-decay of U and Th enriched in crustal materials. A small contribution of mantle origin He was found in the gas reservoirs. Continuous monitoring data indicate 3He/4He ratio didn’t change with the mining time.

  12. Heating hydrocarbon containing formations in a spiral startup staged sequence

    Science.gov (United States)

    Vinegar, Harold J.; Miller, David Scott

    2009-12-15

    Methods for treating a hydrocarbon containing formation are described herein. Methods may include treating a first zone of the formation. Treatment of a plurality of zones of the formation may be begun at selected times after the treatment of the first zone begins. The treatment of at least two successively treated zones may begin at a selected time after treatment of the previous zone begins. At least two of the successively treated zones may be adjacent to the zone treated previously. The successive treatment of the zones proceeds in an outward, substantially spiral sequence from the first zone so that the treatment of the zones may move substantially spirally outwards towards a boundary of the treatment area.

  13. Contribution of methyl group to secondary organic aerosol formation from aromatic hydrocarbon photooxidation

    Science.gov (United States)

    Li, Lijie; Qi, Li; Cocker, David R.

    2017-02-01

    The complete atmospheric oxidation pathways leading to secondary organic aerosol remain elusive for aromatic compounds including the role of methyl substitutes on oxidation. This study investigates the contribution of methyl group to Secondary Organic Aerosol (SOA) formation during the photooxidation of aromatic hydrocarbons under low NOx condition by applying methyl carbon labeled aromatic hydrocarbons ((13C2) m-xylene and (13C2) p-xylene). Particle and gas phase oxidation products are analyzed by a series of mass spectrometers (HR-TOF-AMS, PTR-MS and SIFT-MS). The methyl group carbon containing oxidation products partition to the particle-phase at a lower rate than the carbons originating from the aromatic ring as a result of ring opening reactions. Further, the methyl carbon in the original aromatic structure is at least 7 times less likely to be oxidized when forming products that partition to SOA than the aromatic ring carbon. Therefore, oxidation of the methyl group in xylenes exerts little impact on SOA formation in current study. This study provides supporting evidence for a recent finding - a similarity in the SOA formation and composition from aromatic hydrocarbons regardless of the alkyl substitutes.

  14. The Qishn Formation, Yemen: lithofacies and hydrocarbon habitat

    Energy Technology Data Exchange (ETDEWEB)

    Beydoun, Z.R. (American Univ., Beirut (Lebanon)); Bamahmoud, M.O.; Nani, A.S.O. (Ministry of Oil and Mineral Resources, Sana' a (Yemen, Republic of). Petroleum Exploration and Production Board)

    1993-08-01

    The Barremian-Aptian Qishn Formation of Yemen is broadly described in the context of its role as the lowest widespread transgressive unit of the Cretaceous system in the country and of the two laterally equivalent lithofacies groups that reflect the advance of the Cretaceous sea from east to west. This is undertaken against the background to the tectonic events that preceded its deposition and those that followed it during the remainder of the Cretaceous, so as to better understand its hydrocarbon habitat. (Author)

  15. Formation dynamics of subsurface hydrocarbon intrusions following the Deepwater Horizon blowout

    Science.gov (United States)

    Socolofsky, Scott A.; Adams, E. Eric; Sherwood, Christopher R.

    2011-01-01

    Hydrocarbons released following the Deepwater Horizon (DH) blowout were found in deep, subsurface horizontal intrusions, yet there has been little discussion about how these intrusions formed. We have combined measured (or estimated) observations from the DH release with empirical relationships developed from previous lab experiments to identify the mechanisms responsible for intrusion formation and to characterize the DH plume. Results indicate that the intrusions originate from a stratification-dominated multiphase plume characterized by multiple subsurface intrusions containing dissolved gas and oil along with small droplets of liquid oil. Unlike earlier lab measurements, where the potential density in ambient water decreased linearly with elevation, at the DH site it varied quadratically. We have modified our method for estimating intrusion elevation under these conditions and the resulting estimates agree with observations that the majority of the hydrocarbons were found between 800 and 1200 m.

  16. A 4D synchrotron X-ray tomography study of the formation of hydrocarbon migration pathways in heated organic-rich shale

    CERN Document Server

    Panahi, Hamed; Renard, Francois; Mazzini, Adriano; Scheibert, Julien; Dysthe, Dag Kristian; Jamtveit, Bjorn; Malthe-Sørenssen, Anders; Meakin, Paul

    2014-01-01

    Recovery of oil from oil shales and the natural primary migration of hydrocarbons are closely related processes that have received renewed interests in recent years because of the ever tightening supply of conventional hydrocarbons and the growing production of hydrocarbons from low permeability tight rocks. Quantitative models for conversion of kerogen into oil and gas and the timing of hydrocarbon generation have been well documented. However, lack of consensus about the kinetics of hydrocarbon formation in source rocks, expulsion timing and how the resulting hydrocarbons escape from or are retained in the source rocks motivates further investigation. In particular, many mechanisms for the transport of hydrocarbons from the source rocks in which they are generated into adjacent rocks with higher permeabilities and smaller capillary entry pressures have been proposed, and a better understanding of this complex process (primary migration) is needed. To characterize these processes it is imperative to use the ...

  17. Deposit formation in hydrocarbon rocket fuels: Executive summary

    Science.gov (United States)

    Roback, R.; Szetela, E. J.; Spadaccini, L. J.

    1981-01-01

    An experimental program was conducted to study deposit formation in hydrocarbon fuels under flow conditions that exist in high-pressure, rocket engine cooling systems. A high pressure fuel coking test apparatus was designed and developed and was used to evaluate thermal decomposition (coking) limits and carbon deposition rates in heated copper tubes for two hydrocarbon rocket fuels, RP-1 and commercial-grade propane. Tests were also conducted using JP-7 and chemically-pure propane as being representative of more refined cuts of the baseline fuels. A parametric evaluation of fuel thermal stability was performed at pressures of 136 atm to 340 atm, bulk fuel velocities in the range 6 to 30 m/sec, and tube wall temperatures in the range 422 to 811K. In addition, the effect of the inside wall material on deposit formation was evaluated in selected tests which were conducted using nickel-plated tubes. The results of the tests indicated that substantial deposit formation occurs with RP-1 fuel at wall temperatures between 600 and 800K, with peak deposit formation occurring near 700K. No improvements were obtained when de-oxygenated JP-7 fuel was substituted for RP-1. The carbon deposition rates for the propane fuels were generally higher than those obtained for either of the kerosene fuels at any given wall temperature. There appeared to be little difference between commercial-grade and chemically-pure propane with regard to type and quantity of deposit. The results of tests conducted with RP-1 indicated that the rate of deposit formation increased slightly with pressure over the range 136 atm to 340 atm. Finally, plating the inside wall of the tubes with nickel was found to significantly reduce carbon deposition rates for RP-1 fuel.

  18. 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.

  19. Moving hydrocarbons through portions of tar sands formations with a fluid

    Science.gov (United States)

    Stegemeier, George Leo; Mudunuri, Ramesh Raju; Vinegar, Harold J.; Karanikas, John Michael; Jaiswal, Namit; Mo, Weijian

    2010-05-18

    A method for treating a tar sands formation is disclosed. The method includes heating a first portion of a hydrocarbon layer in the formation from one or more heaters located in the first portion. The heat is controlled to increase a fluid injectivity of the first portion. A drive fluid and/or an oxidizing fluid is injected and/or created in the first portion to cause at least some hydrocarbons to move from a second portion of the hydrocarbon layer to a third portion of the hydrocarbon layer. The second portion is between the first portion and the third portion. The first, second, and third portions are horizontally displaced from each other. The third portion is heated from one or more heaters located in the third portion. Hydrocarbons are produced from the third portion of the formation. The hydrocarbons include at least some hydrocarbons from the second portion of the formation.

  20. Formation Models and Distribution of Oil and Gas Pools in Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    Long Shengxiang

    2008-01-01

    This article reports the main formation models and distribution of the oil and gas pools in Tarim basin,China,including (I) occurrence of the found oil and gas pools,(2) main formation models of oil and gas pools,and (3) distribution law of oil/gas pools.Petroleum is distributed widely in the strata of Tarim basin from the Sinian at the bottom to the Neogene at the top.However,the found oil and gas fields are mainly distributed in Shaya (沙雅) uplift,Tazhong (塔中) uplift,and Kuche (库车)depression.This article presents 4 main formation models,namely,early formation and long-term preservation,early formation and late reformation,middle-late multiphase-multisource formation,late single-stage formation.Tarim basin is very rich in petroleum resources.Long-term inherited intrabasinal paleohighs and slope zones are the most favorable areas for accumulation of hydrocarbons,but the types of oil and gas pools are different from area to area.The control of unconformities and faults on hydrocarbon accumulating is prominent in Tarim basin.Preservation conditions are of utmost importance.Formation of some oil and gas pools is the result of reforming and re-accumulating of early accumulated hydrocarbons.

  1. Formation History of Polycyclic Aromatic Hydrocarbons in Galaxies

    CERN Document Server

    Seok, Ji Yeon; Asano, Ryosuke S

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are some of the major dust components in the interstellar medium (ISM). We present our evolution models for the abundance of PAHs in the ISM on a galaxy-evolution timescale. We consider shattering of carbonaceous dust grains in interstellar turbulence as the formation mechanism of PAHs while the PAH abundance can be reduced by coagulation onto dust grains, destruction by supernova shocks, and incorporation into stars. We implement these processes in a one-zone chemical evolution model to obtain the evolution of the PAH abundance in a galaxy. We find that PAH formation becomes accelerated above certain metallicity where shattering becomes efficient. For PAH destruction, while supernova shock is the primary mechanism in the metal-poor environment, coagulation is dominant in the metal-rich environment. We compare the evolution of the PAH abundances in our models with observed abundances in galaxies with a wide metallicity range. Our models reproduce both the paucity of PAH...

  2. Polycyclic aromatic hydrocarbons' formation and occurrence in processed food.

    Science.gov (United States)

    Singh, Lochan; Varshney, Jay G; Agarwal, Tripti

    2016-05-15

    Polycyclic aromatic hydrocarbons (PAHs) emerged as an important contaminant group in a gamut of processed food groups like dairy, nuts, herbs, beverages, meat products etc. Different cooking processes and processing techniques like roasting, barbecuing, grilling, smoking, heating, drying, baking, ohmic-infrared cooking etc. contribute towards its formation. The level of PAHs depends on factors like distance from heat source, fuel used, level of processing, cooking durations and methods, whereas processes like reuse, conching, concentration, crushing and storage enhance the amount of PAHs in some food items. This review paper provides insight into the impact of dietary intake of PAHs, its levels and formation mechanism in processed food items and possible interventions for prevention and reduction of the PAHs contamination. The gaps and future prospects have also been assessed.

  3. Inflow of atomic gas fuelling star formation

    DEFF Research Database (Denmark)

    Michałowski, M. J.; Gentile, G.; Hjorth, Jeppe;

    2016-01-01

    Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation in these ga......Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation...... in these galaxies may be fuelled by recent inflow of metal-poor atomic gas. While this process is debated, it can happen in low-metallicity gas near the onset of star formation because gas cooling (necessary for star formation) is faster than the Hi-to-H2 conversion....

  4. Formation of polycyclic aromatic hydrocarbons from acetylene over nanosized olivine-type silicates.

    Science.gov (United States)

    Tian, M; Liu, B S; Hammonds, M; Wang, N; Sarre, P J; Cheung, A S-C

    2012-05-14

    The formation mechanism of polycyclic aromatic hydrocarbon (PAH) molecules in interstellar and circumstellar environments is not well understood although the presence of these molecules is widely accepted. In this paper, addition and aromatization reactions of acetylene over astrophysically relevant nesosilicate particles are reported. Gas-phase PAHs produced from exposure of acetylene gas to crystalline silicates using pulsed supersonic jet expansion (SJE) conditions were detected by time-of-flight mass spectrometry (TOF-MS). The PAHs produced were further confirmed in a separate experiment using a continuous flow fixed-bed reactor in which acetylene was introduced at atmospheric pressure. The gas-phase effluent and solutions of the carbonaceous compounds deposited on the nesosilicate particles were analyzed using gas chromatography-mass spectrometry (GC-MS). A mechanism for PAH formation is proposed in which the Mg(2+) ions in the nesosilicate particles act as Lewis acid sites for the acetylene reactions. Our studies indicate that the formation of PAHs in mixed-chemistry astrophysical environments could arise from acetylene interacting with olivine nano-particles. These nesosilicate particles are capable of providing catalytic centres for adsorption and activation of acetylene molecules that are present in the circumstellar environments of mass-losing carbon stars. The structure and physical properties of the particles were characterized by means of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and high-resolution transmission electron microscopy (HRTEM) techniques.

  5. Hydrocarbon Source Rock Potential of the Sinamar Formation, Muara Bungo, Jambi

    Directory of Open Access Journals (Sweden)

    Moh. Heri Hermiyanto Zajuli

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v1i1.175The Oligocene Sinamar Formation consists of shale, claystone, mudstone, sandstone, conglomeratic sandstone, and intercalation of coal seams. The objective of study was to identify the hydrocarbon source rock potential of the Sinamar Formation based on geochemichal characteristics. The analyses were focused on fine sediments of the Sinamar Formation comprising shale, claystone, and mudstone. Primary data collected from the Sinamar Formation well and outcrops were analyzed according to TOC, pyrolisis analysis, and gas chromatography - mass spectometry of normal alkanes that include isoprenoids and sterane. The TOC value indicates a very well category. Based on TOC versus Pyrolysis Yields (PY diagram, the shales of Sinamar Formation are included into oil prone source rock potential with good to excellent categories. Fine sediments of the Sinamar Formation tend to produce oil and gas originated from kerogen types I and III. The shales tend to generate oil than claystone and mudstone and therefore they are included into a potential source rock. 

  6. Is molecular gas necessary for star formation?

    CERN Document Server

    Glover, S C O

    2011-01-01

    On galactic scales, the surface density of star formation appears to be well correlated with the surface density of molecular gas. This has lead many authors to suggest that there exists a causal relationship between the chemical state of the gas and its ability to form stars -- in other words, the assumption that the gas must be molecular before star formation can occur. We test this hypothesis by modelling star formation within a dense cloud of gas with properties similar to a small molecular cloud using a series of different models of the chemistry, ranging from one in which the formation of molecules is not followed and the gas is assumed to remain atomic throughout, to one that tracks the formation of both H2 and CO. We find that presence of molecules in the gas has little effect on the ability of the gas to form stars: star formation can occur just as easily in atomic gas as in molecular gas. At low densities (< 10^4 cm^-3), the gas is able to cool via C+ fine-structure emission almost as efficiently...

  7. 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.

  8. 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

  9. Acoustic Investigations of Gas and Gas Hydrate Formations, Offshore Southwestern Black Sea*

    Science.gov (United States)

    Kucuk, H. M.; Dondurur, D.; Ozel, O.; Atgin, O.; Sinayuc, C.; Merey, S.; Parlaktuna, M.; Cifci, G.

    2015-12-01

    The Black Sea is a large intercontinental back-arc basin with relatively high sedimentation rate. The basin was formed as two different sub-basins divided by Mid-Black Sea Ridge. The ridge is completely buried today and the Black Sea became a single basin in the early Miocene that is currently anoxic. Recent acoustic investigations in the Black Sea indicate potential for gas hydrate formation and gas venting. A total of 2500 km multichannel seismic, Chirp sub-bottom profiler and multibeam bathymetry data were collected during three different expeditions in 2010 and 2012 along the southwestern margin of the Black Sea. Box core sediment samples were collected for gas cromatography analysis. Wide spread BSRs and multiple BSRs are observed in the seismic profiles and may be categorized into two different types: cross-cutting BSRs (transecting sedimentary strata) and amplitude BSRs (enhanced reflections). Both types mimic the seabed reflection with polarity reversal. Some undulations of the BSR are observed along seismic profiles probably caused by local pressure and/or temperature changes. Shallow gas sources and chimney vents are clearly indicated by bright reflection anomalies in the seismic data. Gas cromatography results indicate the presence of methane and various components of heavy hydrocarbons, including Hexane. These observations suggest that the gas forming hydrate in the southwestern Black Sea may originate from deeper thermogenic hydrocarbon sources. * This study is supported by 2214-A programme of The Scientific and Technological Research Council of Turkey (TÜBITAK).

  10. Some practical aspects of log interpretation of gas-bearing formations

    Energy Technology Data Exchange (ETDEWEB)

    Banthia, B.S.

    1977-01-01

    Computerized log interpretation is a standard technique of formation evaluation. Gas can be detected in shaly sandstone formation by combined neutron-density porosity logs, but if the hydrocarbon density is less than 0.8 g/cc, a correction must be made for the hydrocarbon effect on the neutron and density logs. A correction has also to be made for shaliness. A method for obtaining a crossplot porosity value is given. Log interpretation of geopressured gas condensate reservoirs is also discussed. (DLC)

  11. The formation of polycyclic aromatic hydrocarbons in evolved circumstellar environments

    CERN Document Server

    Cherchneff, Isabelle

    2010-01-01

    The formation of Polycyclic Aromatic Hydrocarbons in the circumstellar outflows of evolved stars is reviewed, with an emphasis on carbon stars on the Asymptotic Giant Branch. Evidence for PAHs present in their winds is provided by meteoritic studies and recent observations of the Unidentified Infrared bands. We detail the chemical processes leading to the closure of the first aromatic ring as well as the growth mechanisms leading to amorphous carbon grains. Existing studies on PAH formation in evolved stellar envelopes are reviewed and new results for the modelling of the inner wind of the archetype carbon star IRC+10216 are presented. Benzene, C6H6, forms close to the star, as well as water, H2O, as a result of non-equilibrium chemistry induced by the periodic passage of shocks. The growth process of aromatic rings may thus resemble that active in sooting flames due to the presence of radicals like hydroxyl, OH. Finally, we discuss possible formation processes for PAHs and aromatic compounds in the hydrogen-...

  12. Study of Formation Mechanisms of Gas Hydrate

    Science.gov (United States)

    Yang, Jia-Sheng; Wu, Cheng-Yueh; Hsieh, Bieng-Zih

    2015-04-01

    Gas hydrates, which had been found in subsurface geological environments of deep-sea sediments and permafrost regions, are solid crystalline compounds of gas molecules and water. The estimated energy resources of hydrates are at least twice of that of the conventional fossil fuel in the world. Gas hydrates have a great opportunity to become a dominating future energy. In the past years, many laboratory experiments had been conducted to study chemical and thermodynamic characteristics of gas hydrates in order to investigate the formation and dissociation mechanisms of hydrates. However, it is difficult to observe the formation and dissociation of hydrates in a porous media from a physical experiment directly. The purpose of this study was to model the dynamic formation mechanisms of gas hydrate in porous media by reservoir simulation. Two models were designed for this study: 1) a closed-system static model with separated gas and water zones; this model was a hydrate equilibrium model to investigate the behavior of the formation of hydrates near the initial gas-water contact; and 2) an open-system dynamic model with a continuous bottom-up gas flow; this model simulated the behavior of gas migration and studied the formation of hydrates from flowed gas and static formation water in porous media. A phase behavior module was developed in this study for reservoir simulator to model the pressure-volume-temperature (PVT) behavior of hydrates. The thermodynamic equilibriums and chemical reactions were coupled with the phase behavior module to have functions modelling the formation and dissociation of hydrates from/to water and gas. The simulation models used in this study were validated from the code-comparison project proposed by the NETL. According to the modelling results of the closed-system static model, we found that predominated location for the formation of hydrates was below the gas-water contact (or at the top of water zone). The maximum hydrate saturation

  13. 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.

  14. 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.

  15. 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.

  16. Time sequenced heating of multiple layers in a hydrocarbon containing formation

    Science.gov (United States)

    Goldberg, Bernard; Hale, Arthur Herman; Miller, David Scott; Vinegar, Harold J.

    2009-12-22

    A method for treating a hydrocarbon containing formation may include providing heat to a first hydrocarbon layer in the formation from a first heater located in an opening in the formation. The opening and the first heater may have a horizontal or inclined portion located in the first hydrocarbon layer and at least one connecting portion extending between the horizontal or inclined portion and the surface. Isolation material is placed in the opening such that the isolation material partially isolates the layer in which the horizontal or inclined portion of the first heater is located. An additional horizontal or inclined opening portion that extends from at least one of the connecting portions of the opening is formed in a second hydrocarbon layer. A second heater to provide heat the second hydrocarbon formation is placed in the additional substantially horizontal opening portion.

  17. 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.

  18. Potential for deep basin-centered gas accumulation in Travis Peak (Hosston) Formation, Gulf Coastal Basin

    Science.gov (United States)

    Bartberger, Charles E.; Dyman, Thaddeus S.; Condon, Steven M.

    2003-01-01

    The potential of Lower Cretaceous sandstones of the Travis Peak Formation in the northern Gulf Coast Basin to harbor a basin-centered gas accumulation was evaluated by examining (1) the depositional and diagenetic history and reservoir properties of Travis Peak sandstones, (2) the presence and quality of source rocks for generating gas, (3) the burial and thermal history of source rocks and time of gas generation and migration relative to tectonic development of Travis Peak traps, (4) gas and water recoveries from drill-stem and formation tests, (5) the distribution of abnormal pressures based on shut-in-pressure data, and (6) the presence or absence of gas-water contacts associated with gas accumulations in Travis Peak sandstones. The Travis Peak Formation (and correlative Hosston Formation) is a basinward-thickening wedge of terrigenous clastic sedimentary rocks that underlies the northern Gulf Coast Basin from eastern Texas across northern Louisiana to southern Mississippi. Clastic infl ux was focused in two main fl uvial-deltaic depocenters?one located in northeastern Texas and the other in southeastern Mississippi and northeastern Louisiana. Across the main hydrocarbon-productive trend in eastern Texas and northern Louisiana, the Travis Peak Formation is about 2,000 ft thick. Most Travis Peak hydrocarbon production in eastern Texas comes from drilling depths between 6,000 and 10,000 ft. Signifi cant decrease in porosity and permeability occurs through that depth interval. Above 8,000-ft drilling depth in eastern Texas, Travis Peak sandstone matrix permeabilities often are signifi cantly higher than the 0.1-millidarcy (mD) cutoff that characterizes tight-gas reservoirs. Below 8,000 ft, matrix permeability of Travis Peak sandstones is low because of pervasive quartz cementation, but abundant natural fractures impart signifi cant fracture permeability. Although pressure data within the middle and lower Travis Peak Formation are limited in eastern Texas

  19. Main controlling factors for hydrocarbon reservoir formation and petroleum distribution in Cratonic Area of Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Cratonic Area of the Tarim Basin is located in the central part of the basin, developing primarily with Cambrian marine source rocks and secondly Middle to Upper Ordovician marine and Carboniferous-Permian transitional facies source rocks. The source rocks were matured in the changeable period and space, forming multiple hydrocarbon generating centers during the periods. The Cratonic Area experienced multiple tectonic orogenies, forming several palaeouplifts. The matching condition between effective hydrocarbon generating centers and the palaeouplifts in various periods is the main control factor for the formation and distribution of hydrocarbon reservoirs. The palaeouplifts have experienced multiple hydrocarbon-filling phases, several periods of modifications and even breakdown. The palaeouplifts and the adjacent slopes around the effective hydrocarbon generating center compose the most favorable places for hydrocarbon accumulation. The hydrocarbon phase is related with the evolution of the hydrocarbon generating center. In the Tarim Basin's Cratonic Area, reservoirs were mostly formed during late Hercynian. The originally formed hydrocarbon reservoirs which are adjacent to source kitchens and in the good preservation condition are the most favorable prospecting targets. Hydrocarbon is richly accumulated under the regional caprock, surrounding the faulted trends, and over and below the unconformity surfaces. Reservoirs in the Carboniferous sandstone, Ordovician karstic weathered crust and carbonate rock inside the buried hill compose the main intervals for hydrocarbon accumulation. Carboniferous and Silurian sandstone pinchout reservoirs and carbonate lithologic reservoirs with rich fractures and pores are the main targets for further prospecting.

  20. Gas-Phase Infrared; JCAMP Format

    Science.gov (United States)

    SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

  1. Solution mining dawsonite from hydrocarbon containing formations with a chelating agent

    Science.gov (United States)

    Vinegar, Harold J.

    2009-07-07

    A method for treating an oil shale formation comprising dawsonite includes providing heat from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation. At least some dawsonite in the formation is decomposed with the provided heat. A chelating agent is provided to the formation to dissolve at least some dawsonite decomposition products. The dissolved dawsonite decomposition products are produced from the formation.

  2. Solution mining and heating by oxidation for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; Stegemeier, George Leo

    2009-06-23

    A method for treating an oil shale formation comprising nahcolite includes providing a first fluid to a portion of the formation. A second fluid is produced from the portion. The second fluid includes at least some nahcolite dissolved in the first fluid. A controlled amount of oxidant is provided to the portion of the formation. Hydrocarbon fluids are produced from the formation.

  3. Solution mining and heating by oxidation for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; Stegemeier, George Leo

    2009-06-23

    A method for treating an oil shale formation comprising nahcolite includes providing a first fluid to a portion of the formation. A second fluid is produced from the portion. The second fluid includes at least some nahcolite dissolved in the first fluid. A controlled amount of oxidant is provided to the portion of the formation. Hydrocarbon fluids are produced from the formation.

  4. Formation rate of natural gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Mork, Marit

    2002-07-01

    The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

  5. In situ recovery from residually heated sections in a hydrocarbon containing formation

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX); Ryan, Robert Charles (Houston, TX)

    2010-12-14

    Methods of treating a tar sands formation is described herein. The methods may include providing heat to a first section of a hydrocarbon layer in the formation from a plurality of heaters located in the first section of the formation. Heat is transferred from the heaters so that at least a first section of the formation reaches a selected temperature. At least a portion of residual heat from the first section transfers from the first section to a second section of the formation. At least a portion of hydrocarbons in the second section are mobilized by providing a solvation fluid and/or a pressurizing fluid to the second section of the formation.

  6. 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.

  7. 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...

  8. 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

  9. Effects of Large Polycyclic Aromatic Hydrocarbons on the Soot Formation in Ethylene-Air Nonpremixed Flames

    KAUST Repository

    Prabhu, S.

    2015-03-30

    This study presents updated comprehensive gas-phase kinetic mechanism and aerosol models to predict soot formation characteristics in ethylene-air nonpremixed flames. A main objective is to investigate the sensitivity of the soot formation rate to various chemical pathways for large polycyclic aromatic hydrocarbons (PAH). In this study, the detailed chemical mechanism was reduced from 397 to 99 species using directed relation graph (DRG) and sensitivity analysis. The method of moments with interpolative closure (MOMIC) was employed for the soot aerosol model. Counterflow nonpremixed flames of pure ethylene at low strain rate sooting conditions are considered, for which the sensitivity of soot formation characteristics with respect to hetrogeneous nucleation is investigated. Results show that higher PAH concentrations result in higher soot nucleation rate, and that the average size of the particles are in good agreement with experimental results. It is found that the nucleation processes (i.e., soot inception) from higher PAH precursors, coronene in particular, is critical for accurate prediction of the overall soot formation.

  10. 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.

  11. 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.

  12. Certain features of the formation of accumulations of hydrocarbons in the Mesozoic sediments of teh Nadym-Tazovsk interfluve

    Energy Technology Data Exchange (ETDEWEB)

    Rysev, V.V.

    1981-01-01

    The role is shown of migration processes in the formation and disposition of accumulations of hydrocarbons relative to the facial-lithological features of the section. Special attention is focused on the process of formation of hydrocarbon accumulations in shelf strata. Certain recommendations are given in regards to the exploration for new hydrocarbon deposits.

  13. 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.

  14. 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

  15. Importance of Aqueous-phase Secondary Organic Aerosol Formation from Aromatics in an Atmospheric Hydrocarbon Mixture

    Science.gov (United States)

    Parikh, H. M.; Carlton, A. G.; Vizuete, W.; Zhang, H.; Zhou, Y.; Chen, E.; Kamens, R. M.

    2010-12-01

    Two new secondary organic aerosol (SOA) modeling frameworks are developed, one based on an aromatic gas and particle-phase kinetic mechanism and another based on a parameterized SOA model used in conjunction with an underlying gas-phase mechanism, both of which simulate SOA formation through partitioning to two stable liquid phases: one hydrophilic containing particle aqueous-phase and the other hydrophobic comprising mainly organic components. The models were evaluated against outdoor smog chamber experiments with different combinations of initial toluene, o-xylene, p-xylene, toluene and xylene mixtures, NOx, non-SOA-forming hydrocarbon mixture, initial seed type, and humidity. Aerosol data for experiments with either ammonium sulfate or initial background seed particles, in the presence of an atmospheric hydrocarbon mixture, NOx and in sunlight under a dry atmosphere (RH = 6 to 10%) show reduced SOA formation when compared to experiments with similar initial gas and particle concentrations at higher relative humidities (RH = 40 to 90%). Both frameworks simulated reasonable fits to the total observed SOA concentrations under all conditions. For both dry and wet experiments with low initial seed, semi-volatile product partitioning in particle organic-phase is mass-transfer limited and is modeled using a dynamic gas-particle partitioning algorithm with accommodation coefficient as the primary pseudo-transport parameter. Further, the modeled SOA product distributions for both frameworks clearly show the importance of the contribution of aqueous-phase SOA particularly under conditions of low initial seed concentrations and high-humidity. For both models, under these conditions, aqueous-phase SOA from uptake of glyoxal, methylglyoxal and related polar products to particle water phase dominates as compared to the partitioning of semi-volatiles to particle organic phase. Interestingly, both the kinetic and parameterized SOA frameworks simulate similar amounts of aqueous

  16. 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.

  17. 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.

  18. 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.

  19. Molecular Gas and Star Formation in Voids

    CERN Document Server

    Das, M; Iono, D; Honey, M; Ramya, S

    2014-01-01

    We present the detection of molecular gas using CO(1-0) line emission and follow up Halpha imaging observations of galaxies located in nearby voids. The CO(1-0) observations were done using the 45m telescope of the Nobeyama Radio Observatory (NRO) and the optical observations were done using the Himalayan Chandra Telescope (HCT). Although void galaxies lie in the most under dense parts of our universe, a significant fraction of them are gas rich, spiral galaxies that show signatures of ongoing star formation. Not much is known about their cold gas content or star formation properties. In this study we searched for molecular gas in five void galaxies using the NRO. The galaxies were selected based on their relatively higher IRAS fluxes or Halpha line luminosities. CO(1--0) emission was detected in four galaxies and the derived molecular gas masses lie between (1 - 8)E+9 Msun. The H$\\alpha$ imaging observations of three galaxies detected in CO emission indicates ongoing star formation and the derived star forma...

  20. Isotope Geochemistry of Natural Gas in Xujiahe Formation of the Upper Triassic in Sichuan Basin, China

    Science.gov (United States)

    Tao, Shizhen; Mi, Jingkui; Yang, Chun; Gao, Xiaohui; Wu, Songtao; Pang, Zhenglian; Fan, Jianwei

    2017-04-01

    Terrestrial tight sandstone gas is abundant Xujiahe(XJH) Formation in Sichuan Basin, China. Its reserve is over 0.6×1012m3. Though has such a huge reserve, origin and evolution of this tight sandstone gas haven't been studied thoroughly. This study is to clarify geochemical characteristics of gas formation and evolution in XJH Formation based on the comparative geochemical analysis of gas samples from fluid inclusions and gas fields. Experiments showed the great differences between gas in inclusions and from fields. There are low-medium maturity coal-derived tight sandstone gases in XJH Formation. Source rocks are mainly kerogen type-II2 and III, but coal series are type-III. The Ro is 0.8-1.4%. They are presently at post-mature to early high-mature stage, but the gas/oil ratio in present gas reservoirs is high. XJH reservoir rocks have large amount of gaseous hydrocarbon inclusions, few liquid hydrocarbon inclusions, indicating coal series type generates mainly gas (Dai et al., 1997; 2012). XJH natural gas is dominated by methane, with higher concentration of heavier C2+ hydrocarbons, belonging to kerogen-degraded gas. The gas dryness ratios are normally less than 0.95, mainly wet gas. The content of methane in the inclusions is low, rather lower for those of C2+ hydrocarbons, while that of non-hydrocarbons (CO2) is higher. Isotopic features show that tight sandstone gas of XJH Formation is typical coal-derived gas. The gas δ13C1 ranges from -45.5‰ to -36.5‰ and δ13C2 from -30‰ to -25‰.The δ13C1 and δ13C2 in fluid inclusions are similar, but mostly slightly heavier, with a δ13C1 of -36‰ -45‰ and δ13C2 of -24.8‰ -28.1‰, characterized as coal-type gas. The δ13CCO2 of gas from fields ranges from -15.6‰ to -5.6‰, and that of inclusions is lighter, ranging from -16.6‰ to -9‰, which is organic origin. The CO2 captured in the inclusions in a relatively closed system, characterizing as heavier carbon isotopic composition for alkane gas and

  1. Evaluation of the geological relationships to gas hydrate formation and stability

    Energy Technology Data Exchange (ETDEWEB)

    Krason, J.; Finley, P.

    1988-01-01

    The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

  2. 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.

  3. 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.)

  4. 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.

  5. Methanogenic degradation of petroleum hydrocarbons in subsurface environments remediation, heavy oil formation, and energy recovery.

    Science.gov (United States)

    Gray, N D; Sherry, A; Hubert, C; Dolfing, J; Head, I M

    2010-01-01

    Hydrocarbons are common constituents of surface, shallow, and deep-subsurface environments. Under anaerobic conditions, hydrocarbons can be degraded to methane by methanogenic microbial consortia. This degradation process is widespread in the geosphere. In comparison with other anaerobic processes, methanogenic hydrocarbon degradation is more sustainable over geological time scales because replenishment of an exogenous electron acceptor is not required. As a consequence, this process has been responsible for the formation of the world's vast deposits of heavy oil, which far exceed conventional oil assets such as those found in the Middle East. Methanogenic degradation is also a potentially important component of attenuation in hydrocarbon contamination plumes. Studies of the organisms, syntrophic partnerships, mechanisms, and geochemical signatures associated with methanogenic hydrocarbon degradation have identified common themes and diagnostic markers for this process in the subsurface. These studies have also identified the potential to engineer methanogenic processes to enhance the recovery of energy assets as biogenic methane from residual oils stranded in petroleum systems.

  6. Characteristics of hydrocarbon sources and controlling factors of their formation in Pingliang Formation, West Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to organic geochemistry and organic petrology, the hydrocarbon sources in Pingliang Formation, W. Ordos basin, are systematically evaluated. The organic abundance of hydrocarbon source in this research is higher in the upper part of profiles than In the low, and more in mudstone than in carbonate. Most of organic matters become sapropelic, and few are humlc-aapropelic in the regions of Shibangou and Zhuzisan. According to stable isotopes of carbon and oxygen in carbonate rock, boron index and ratios of elements, palaeo-salinity and sedimentary velocity are calculated. The two factors of paleao-salinity and sediment velocity, which control the distribution of organic matters, are discussed.Good relationship is found between water salinity and abundance of organic matter; in contrast, poor correlation is observed between salinity and types of organic matters. The relative sediment velocity in the research regions is also related with organic abundance and types. A low sediment velocity would lead to high abundance and good type of organic matters, and vice versa.

  7. KINETICS OF THE GAS-SLURRY METHANOL-HIGHER ALCOHOL SYNTHESIS FROM CO/CO2/H-2 OVER A CS-CU/ZNO/AL2O3 CATALYST, INCLUDING SIMULTANEOUS FORMATION OF METHYL-ESTERS AND HYDROCARBONS

    NARCIS (Netherlands)

    BREMAN, BB; BEENACKERS, AACM; SCHUURMAN, HA; OESTERHOLT, E

    1995-01-01

    First kinetic results are presented for the gas-slurry methanol-higher alcohol synthesis from CO/CO2/H-2 (syngas) over a CU0.44Zn0.43Al0.12Cs0.031 catalyst (particle size: 50-75 mu m), slurried in n-octacosane. Experimental conditions varied as follows: pressure = 20-80 bar, temperature = 473-573 K,

  8. Haloarchaea and the Formation of Gas Vesicles

    Directory of Open Access Journals (Sweden)

    Felicitas Pfeifer

    2015-02-01

    Full Text Available Halophilic Archaea (Haloarchaea thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes.

  9. [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.

  10. Investigation on Methane Decomposition and the Formation of C2 Hydrocarbons in DC Discharge Plasma byEmission Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    贺建勋; 韩媛媛; 高爱华; 周引穗; 陆治国

    2004-01-01

    The IR emission spectra of methane were measured under DC glow discharge conditions. The distinct difference in time between methane decomposition and C2 hydrocarbons formation was specially pointed out. C2 hydrocarbons formed at the end of methane decomposition. The optimum condition for C2 hydrocarbon formation was studied and the optimum combination between electric current density and methane input quantity was suggested. The appropriate reaction conditions for methane decomposition and C2 hydrocarbons formation are different, so high yield of C2 hydrocarbons will be probably obtained when different conditions are taken.

  11. Coke Formation in a Zeolite Crystal During the Methanol-to-Hydrocarbons Reaction as Studied with Atom Probe Tomography.

    Science.gov (United States)

    Schmidt, Joel E; Poplawsky, Jonathan D; Mazumder, Baishakhi; Attila, Özgün; Fu, Donglong; de Winter, D A Matthijs; Meirer, Florian; Bare, Simon R; Weckhuysen, Bert M

    2016-09-01

    Understanding the formation of carbon deposits in zeolites is vital to developing new, superior materials for various applications, including oil and gas conversion processes. Herein, atom probe tomography (APT) has been used to spatially resolve the 3D compositional changes at the sub-nm length scale in a single zeolite ZSM-5 crystal, which has been partially deactivated by the methanol-to-hydrocarbons reaction using (13) C-labeled methanol. The results reveal the formation of coke in agglomerates that span length scales from tens of nanometers to atomic clusters with a median size of 30-60 (13) C atoms. These clusters correlate with local increases in Brønsted acid site density, demonstrating that the formation of the first deactivating coke precursor molecules occurs in nanoscopic regions enriched in aluminum. This nanoscale correlation underscores the importance of carefully engineering materials to suppress detrimental coke formation.

  12. 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.

  13. 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

  14. 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

  15. In situ direct sampling mass spectrometric study on formation of polycyclic aromatic hydrocarbons in toluene pyrolysis.

    Science.gov (United States)

    Shukla, Bikau; Susa, Akio; Miyoshi, Akira; Koshi, Mitsuo

    2007-08-30

    The gas-phase reaction products of toluene pyrolysis with and without acetylene addition produced in a flow tube reactor at pressures of 8.15-15.11 Torr and temperatures of 1136-1507 K with constant residence time (0.56 s) have been detected in an in situ direct sampling mass spectrometric study by using a vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry technique. Those products range from methyl radical to large polycyclic aromatic hydrocarbons (PAHs) of mass 522 amu (C(42)H(18)) including smaller species, radicals, polyynes, and PAHs, together with ethynyl, methyl, and phenyl PAHs. On the basis of observed mass spectra, the chemical kinetic mechanisms of the formation of products are discussed. Especially, acetylene is mixed with toluene to understand the effect of the hydrogen abstraction and acetylene addition (HACA) mechanism on the formation pathways of products in toluene pyrolysis. The most prominent outputs of this work are the direct detection of large PAHs and new reaction pathways for the formation of PAHs with the major role of cyclopenta-fused radicals. The basis of this new reaction route is the appearance of different sequences of mass spectra that well explain the major role of aromatic radicals mainly cyclopenta fused radicals of PAHs resulting from their corresponding methyl PAHs, with active participation of c-C(5)H(5), C(6)H(5), C(6)H(5)CH(2) ,and C(9)H(7) in the formation of large PAHs. The role of the HACA only seemed important for the formation of stable condensed PAHs from unstable primary PAHs with zigzag structure (having triple fusing sites) in one step by ring growth with two carbon atoms.

  16. 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

  17. Prediction of Refrigerant Gas Hydrates Formation Conditions

    Institute of Scientific and Technical Information of China (English)

    Deqing Liang; Ruzhu Wang; Kaihua Guo; Shuanshi Fan

    2001-01-01

    A fugacity model was developed for prediction of mixed refrigerant gas hydrates formation conditions based on the molecule congregation and solution theories. In this model, g as hydrates were regarded as non-ideal solid solution composed of water groups and guest molecules, and the expressions of fugacity of guest molecules in hydrate phase was proposed accordingly. It has been shown that the developed model can indicate successfully the effect of guest-guest molecule interaction. The results showed that the model can describe better the characteristics of phase equilibrium of mixed refrigerant gas hydrates and predictions are in good agreement with experimental data.

  18. Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones

    OpenAIRE

    2011-01-01

    Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed different products under the pyrolysis and most of them evolved into polycyclic aromatic hydrocarbons during their residence in the pyrolysis chamber at high temperatures. The products from the pyrolysates, at all temperatures, were analysed for similarities and differences ...

  19. 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

  20. 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.

  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. Gas Price Formation, Structure and Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davoust, R.

    2008-07-01

    Our study, focused on gas prices in importing economies, describes wholesale prices and retail prices, their evolution for the last one or two decades, the economic mechanisms of price formation. While an international market for oil has developed thanks to moderate storage and transportation charges, these costs are much higher in the case of natural gas, which involves that this energy is still traded inside continental markets. There are three regional gas markets around the world: North America (the United States, importing mainly from Canada and Mexico), Europe (importing mainly from Russia, Algeria and Norway) and Asia (Japan, Korea, Taiwan, China and India, importing mainly from Indonesia, Malaysia and Australia). A market for gas has also developed in South America, but it will not be covered by our paper. In Europe and the US, due to large domestic resources and strong grids, natural gas is purchased mostly through pipelines. In Northeast Asia, there is a lack of such infrastructures, so imported gas takes mainly the form of Liquefied Natural Gas (LNG), shipped on maritime tankers. Currently, the LNG market is divided into two zones: the Atlantic Basin (Europe and US) and the Pacific Basin (Asia and the Western Coast of America). For the past few years, the Middle East and Africa have tended to be crucial suppliers for both LNG zones. Gas price formation varies deeply between regional markets, depending on several structural factors (regulation, contracting practises, existence of a spot market, liquidity, share of imports). Empirically, the degree of market opening (which corresponds to the seniority in the liberalization process) seems to be the primary determinant of pricing patterns. North America has the most liberalized and well-performing natural gas industry in the world. Gas pricing is highly competitive and is based on supply/demand balances. Spot and futures markets are developed. The British gas sector is also deregulated and thus follows a

  8. Formation of hydrocarbons by micro-organisms. [Review with 152 references

    Energy Technology Data Exchange (ETDEWEB)

    Bird, C.W. (Queen Elizabeth Coll., London); Lynch, J.M.

    1974-01-01

    A review covers the formation of methane, e.g., by Methanobacterium ruminantium on hydrogen and carbon dioxide substrate in swamps, sewage plants, etc.; ethylene, e.g., from plant pathogens such as Penicillium digitatum in citrus fruits; other short-chain hydrocarbons, e.g., hexa-1,3,5-triyne, formed by the fungus Fomes annosus; longer-chain hydrocarbons, e.g., C/sub 16/-C/sub 33/ alkanes formed by algae and fungi, with the chain lengths dependent upon the carbon source used for growth; isoprenoid hydrocarbons, e.g., squalene, formed by yeasts and fungi; and geochemical aspects, such as the microbial contributions to petroleum formation. 152 references.

  9. Ice Formation in Gas-Diffusion Layers

    Energy Technology Data Exchange (ETDEWEB)

    Dursch, Thomas; Radke, Clayton J.; Weber, Adam Z.

    2010-07-10

    Under sub-freezing conditions, ice forms in the gas-diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) drastically reducing cell performance. Although a number of strategies exist to prevent ice formation, there is little fundamental understanding of the mechanisms of freezing within PEMFC components. Differential scanning calorimetry (DSC) is used to elucidate the effects of hydrophobicity (Teflon® loading) and water saturation on the rate of ice formation within three commercial GDLs. We find that as the Teflon® loading increases, the crystallization temperature decreases due to a change in internal ice/substrate contact angle, as well as the attainable level of water saturation. Classical nucleation theory predicts the correct trend in freezing temperature with Teflon® loading.

  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. Post-Neogene Structural Evolution:An Important Geological Stage in the Formation of Gas Reservoirs in China

    Institute of Scientific and Technical Information of China (English)

    WANG Tingbin

    2004-01-01

    Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post-Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic movements since the Neogene. These movements have certainly caused destruction to the reservoiring and distribution of natural gas in China, which has resulted in a certain dissipation of natural gas in some basins. As a whole, however, they have mainly promoted the reservoiring and accumulation of natural gas: (1) a series of China-type foreland basins have been formed between basins and ridges in western China, which provide favorable conditions for the formation of large and medium gas fields, as well as controlling the finalization of gas reservoirs in the basins; (2) rows and belts of anticlines have been formed in the Sichuan Basin in central China, which have been the major stages of the formation and finalization of gas reservoirs in that basin; the integral and quick rising and lifting, and a further west-dipping in the Ordos Basin have resulted in a further accumulation of natural gas in gas fields from Jingbian to Uxin; (3) in eastem China, the Bohai movement in the late Pliocene has provided favorable geological conditions for lately-formed gas reservoirs in the Bohai Sea area mainly composed of the Bozhong depression; and it also resulted in secondary hydrocarbon generation and

  12. Empirical modeling of soot formation in shock-tube pyrolysis of aromatic hydrocarbons

    Science.gov (United States)

    Frenklach, M.; Clary, D. W.; Matula, R. A.

    1986-01-01

    A method for empirical modeling of soot formation during shock-tube pyrolysis of aromatic hydrocarbons is developed. The method is demonstrated using data obtained in pyrolysis of argon-diluted mixtures of toluene behind reflected shock waves. The developed model is in good agreement with experiment.

  13. LOW TEMPERATURE FORMATION OF NITROGEN-SUBSTITUTED POLYCYCLIC AROMATIC HYDROCARBONS (PANHs)—BARRIERLESS ROUTES TO DIHYDRO(iso)QUINOLINES

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Dorian S. N.; Yang, Tao; Dangi, Beni B.; Kaiser, Ralf I. [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Bera, Partha P.; Lee, Timothy J., E-mail: ralfk@hawaii.edu, E-mail: Timothy.J.Lee@nasa.gov [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, Mountain View, CA 94035 (United States)

    2015-12-20

    Meteorites contain bio-relevant molecules such as vitamins and nucleobases, which consist of aromatic structures with embedded nitrogen atoms. Questions remain over the chemical mechanisms responsible for the formation of nitrogen-substituted polycyclic aromatic hydrocarbons (PANHs) in extraterrestrial environments. By exploiting single collision conditions, we show that a radical mediated bimolecular collision between pyridyl radicals and 1,3-butadiene in the gas phase forms nitrogen-substituted polycyclic aromatic hydrocarbons (PANHs) 1,4-dihydroquinoline and to a minor amount 1,4-dihydroisoquinoline. The reaction proceeds through the formation of a van der Waals complex, which circumnavigates the entrance barrier implying it can operate at very low kinetic energy and therefore at low temperatures of 10 K as present in cold molecular clouds such as TMC-1. The discovery of facile de facto barrierless exoergic reaction mechanisms leading to PANH formation could play an important role in providing a population of aromatic structures upon which further photo-processing of ice condensates could occur to form nucleobases.

  14. Formation of positive ions in hydrocarbon containing dielectric barrier discharge plasmas

    Science.gov (United States)

    Mihaila, Ilarion; Pohoata, Valentin; Jijie, Roxana; Nastuta, Andrei Vasile; Rusu, Ioana Alexandra; Topala, Ionut

    2016-12-01

    Low temperature atmospheric pressure plasma devices are suitable experimental solutions to generate transitory molecular environments with various applications. In this study we present experimental results regarding the plasma chemistry of dielectric barrier discharges (DBD) in helium - hydrogen (0.1%) - hydrocarbons (1.2%) mixtures. Four types of hydrocarbon gases were studied: methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). Discharge diagnosis and monitoring was assured by electrical measurements and optical emission spectroscopy. Molecular beam mass spectrometry is engaged to sample positive ions populations from two different plasma sources. Dissociation and generation of higher-chain and cyclic (aromatic) hydrocarbons were discussed as a function of feed gas and discharge geometry. We found a strong influence of these parameters on both molecular mass distribution and recombination processes in the plasma volume.

  15. Kinetic modeling of Secondary Organic Aerosol formation: effects of particle- and gas-phase reactions of semivolatile products

    Directory of Open Access Journals (Sweden)

    A. W. H. Chan

    2007-05-01

    Full Text Available The distinguishing mechanism of formation of secondary organic aerosol (SOA is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics, of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms.

  16. Kinetic modeling of secondary organic aerosol formation: effects of particle- and gas-phase reactions of semivolatile products

    Directory of Open Access Journals (Sweden)

    A. W. H. Chan

    2007-08-01

    Full Text Available The distinguishing mechanism of formation of secondary organic aerosol (SOA is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics, of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms.

  17. Nile Red Detection of Bacterial Hydrocarbons and Ketones in a High-Throughput Format

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, NM; Aukema, KG; Gralnick, JA; Wackett, LP

    2011-06-28

    A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones. IMPORTANCE In recent years, there has been renewed interest in advanced biofuel sources such as bacterial hydrocarbon production. Previous studies used solvent extraction of bacterial cultures followed by gas chromatography-mass spectrometry (GC-MS) to detect and quantify ketones and hydrocarbons (Beller HR, Goh EB, Keasling JD, Appl. Environ. Microbiol. 76: 1212-1223, 2010; Sukovich DJ, Seffernick JL, Richman JE, Gralnick JA, Wackett LP, Appl. Environ. Microbiol. 76: 3850-3862, 2010). While these analyses are powerful and accurate, their labor-intensive nature makes them intractable to high-throughput screening; therefore, methods for rapid identification of bacterial strains that are overproducing hydrocarbons are needed. The use of high

  18. Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during coal pyrolysis.

    Science.gov (United States)

    Gao, Meiqi; Wang, Yulong; Dong, Jie; Li, Fan; Xie, Kechang

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure.

  19. Spatially Resolved 3 um Spectroscopy of IRAS 22272+5435 Formation and Evolution of Aliphatic Hydrocarbon Dust in Proto-Planetary Nebula

    CERN Document Server

    Goto, M; Hayano, Y; Iye, M; Kamata, Y; Kanzawa, T; Kobayashi, N; Minowa, Y; Saint-Jacques, D J; Takami, H; Takato, N; Terada, H

    2003-01-01

    We present medium-resolution 3 um spectroscopy of the carbon-rich proto-planetary nebula IRAS 22272+5435. Spectroscopy with the Subaru Telescope adaptive optics system revealed a spatial variation of hydrocarbon molecules and dust surrounding the star. The ro-vibrational bands of acetylene (C2H2) and hydrogen cyanide (HCN) at 3.0 um are evident in the central star spectra. The molecules are concentrated in the compact region near the center. The 3.3 and 3.4 um emission of aromatic and aliphatic hydrocarbons is detected at 600--1300 AU from the central star. The separation of spatial distribution between gas and dust suggests that the small hydrocarbon molecules are indeed the source of solid material, and that the gas leftover from the grain formation is being observed near the central star. The intensity of aliphatic hydrocarbon emission relative to the aromatic hydrocarbon emission decreases with distance from the central star. The spectral variation is well matched to that of a laboratory analog thermally ...

  20. 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.

  1. 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...

  2. Kinetics of Hydrocarbon formation in a- C:H Film deposition plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cal, E. de la; Tabares, F. L.

    1993-07-01

    The formation of C2 and Cp hydrocarbons during the PACVD of a-C:H films from admixtures of methane with H2 and He has been investigated by mass spectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanisms of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene formation was found to be directly related to the formation of the film on top of the carburized metal. (Author) 12 refs.

  3. EXPERIMENTAL EVIDENCE FOR THE FORMATION OF HIGHLY SUPERHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS THROUGH H ATOM ADDITION AND THEIR CATALYTIC ROLE IN H2 FORMATION

    DEFF Research Database (Denmark)

    Thrower, John; Jørgensen, Bjarke; Friis, Emil Enderup;

    2012-01-01

    Mass spectrometry measurements show the formation of highly superhydrogenated derivatives of the polycyclic aromatic hydrocarbon molecule coronene through H atom addition reactions. The observed product mass distribution provides evidence also for abstraction reactions resulting in H2 formation...

  4. 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...

  5. 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%...

  6. Formation Mechanism of the High-quality Upper Paleozoic Natural Gas Reservoirs in the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; WANG Zecheng; CHEN Menjin; ZHENG Hongju

    2005-01-01

    The upper Paleozoic natural gas reservoirs in the Ordos basin are generally characterized by a large gas-bearing area and low reserve abundance. On such a geological background, there still exist gas-enriched zones, with relatively high outputs, high reserve abundance and stably distributed gas layers. The gas-enriched layers with relatively high permeability (the lower limit permeability is 0.5×l0-3 μm2) are key factors for the enrichment and high output of natural gas. Based on core observation, analytic results of inclusions, and a great deal of drilling data, we proposed the following four mechanisms for the formation of high-quality reservoirs: (1) in the source area the parent rocks are mainly metamorphic rocks and granites, which are favorable to keeping primary porosity; (2) under the condition of low A/S (accommodation/sediment supply) ratios,sandstone complex formed due to multistage fluvial stacking and filling are coarse in grain size with a high degree of sorting,low content of mud and good physical properties; (3) early-stage recharge of hydrocarbons restricted compaction and cementation, and thus are favorable to preservation of primary pores; (4) microfractures caused by the activity of basement faults during the Yanshan Movement stage can not only improve the permeability of tight sandstones, but also afford vertical pathways for hydrocarbon gas migration.

  7. 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...

  8. Zeolite-Catalyzed Hydrocarbon Formation from Methanol: Density Functional Simulations

    Directory of Open Access Journals (Sweden)

    George Fitzgerald

    2002-04-01

    Full Text Available Abstract: We report detailed density functional theory (DFT calculations of important mechanisms in the methanol to gasoline (MTG process in a zeolite catalyst. Various reaction paths and energy barriers involving C-O bond cleavage and the first C-C bond formation are investigated in detail using all-electron periodic supercell calculations and recently developed geometry optimization and transition state search algorithms. We have further investigated the formation of ethanol and have identified a different mechanism than previously reported [1], a reaction where water does not play any visible role. Contrary to recent cluster calculations, we were not able to find a stable surface ylide structure. However, a stable ylide structure built into the zeolite framework was found to be possible, albeit a very high reaction barrier.

  9. 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.

  10. 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.

  11. Normal hydrocarbons as a source of resin formation in the process of obtaining isoprene from isopentane

    Energy Technology Data Exchange (ETDEWEB)

    Isagulyants, G.V.; Sire, Y.M.; Vasil' yeva, V.P.; Gitis, K.M.; Rozengart, M.I.

    1981-01-01

    A study was made on a catalyst of dehydrogenation of olefins of the conversion of isoamylenes and other C/sub 5/ hydrocarbons (isoprene, n-pentenes, piperylene), formed during dehydrogenation of isoamylenes to isoprene. It was found that the yield of heavy products increases on transition from hydrocarbons of iso-structure to normal hydrocarbons, which is due to the greater ease of polycondensation of cyclopentadiene formed from n-pentenes and particularly from piperylene under conditions of dehydrogenation. A study was made by chromato-mass-spectrometry of the composition of heavy products of conversion of piperylene and isoprene. In contrast with the catalysate of isoprene, the catalysate of piperylene contains a significant proportion of hydrocarbons containing a five-membered ring in the molecule (dicyclopentadiene, indane, indene, methylindenes, azilene), this being due to the participation of cyclopentadiene in the formation of heavy products. In the two-stage process of dehydrogenation of isopentane to isoprene 95% normal hydrocarbons are formed on dehydrogenation of isopentane to isoamylenes. (JMT)

  12. 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.

  13. 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.

  14. 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

  15. Estimation of subsurface formation temperature in the Tarim Basin, northwest China: implications for hydrocarbon generation and preservation

    Science.gov (United States)

    Liu, Shaowen; Lei, Xiao; Feng, Changge; Hao, Chunyan

    2016-07-01

    Subsurface formation temperature in the Tarim Basin, northwest China, is vital for assessment of hydrocarbon generation and preservation, and of geothermal energy potential. However, it has not previously been well understood, due to poor data coverage and a lack of highly accurate temperature data. Here, we combined recently acquired steady-state temperature logging data with drill stem test temperature data and measured rock thermal properties, to investigate the geothermal regime and estimate the subsurface formation temperature at depth in the range of 1000-5000 m, together with temperatures at the lower boundary of each of four major Lower Paleozoic marine source rocks buried in this basin. Results show that heat flow of the Tarim Basin ranges between 26.2 and 66.1 mW/m2, with a mean of 42.5 ± 7.6 mW/m2; the geothermal gradient at depth of 3000 m varies from 14.9 to 30.2 °C/km, with a mean of 20.7 ± 2.9 °C/km. Formation temperature estimated at the depth of 1000 m is between 29 and 41 °C, with a mean of 35 °C, while 63-100 °C is for the temperature at the depth of 3000 m with a mean of 82 °C. Temperature at 5000 m ranges from 97 to 160 °C, with a mean of 129 °C. Generally spatial patterns of the subsurface formation temperature at depth are basically similar, characterized by higher temperatures in the uplift areas and lower temperatures in the sags, which indicates the influence of basement structure and lateral variations in thermal properties on the geotemperature field. Using temperature to identify the oil window in the source rocks, most of the uplifted areas in the basin are under favorable condition for oil generation and/or preservation, whereas the sags with thick sediments are favorable for gas generation and/or preservation. We conclude that relatively low present-day geothermal regime and large burial depth of the source rocks in the Tarim Basin are favorable for hydrocarbon generation and preservation. In addition, it is found that the

  16. The formation mechanism of high-quality dolomite reservoir in the deep of Puguang Gas Field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The discovery of Puguang Gas Field provides the exploration of China deep marine carbonate rock with important references.In Puguang Gas Field,the dolomite reservoirs discovered in the deep are the best in the present of China,which present big thickness and wide-range distribution,and develop abundant secondary porosity.The researches show that Puguang Gas Field bears the characteristics of early gas-filling time,deep burial,high matured organic matter and long-term interaction of hydrocarbon(oil and gas)-water-rock(carbonate reservoir).The developments of secondary pores in this area are affected by multiple diagenesis and their formation mechanisms are complicated.Through the research on depositional environment,sedimentary facies and reservoir porosity characters of Changxing and Feixianguan Formations,it is thought that high-quality dolomite reservoirs of Puguang Gas Field form on the favorable sedimentary facies belts,which are the integrate result affected by several factors including superficial corrosion,burial corrosion,overpressure and tectonic movement,among which burial corrosion of TSR to reservoir and overpressure formed by thermal evolution of organic matter have great effect on the formation of secondary porosity of Changxing and Feixianguan Formations.

  17. 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.

  18. 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.

  19. Causes of gas formations in the urinary tract

    Energy Technology Data Exchange (ETDEWEB)

    Jenett, M.; Hollihan, K.; Longin, F.

    1985-01-01

    During diagnostic procedures for various diseases, five patients underwent intravenous pyelograms which showed gas formations in the collector system, in absence of acute stmptoms. Laboratory chemical, bacteriologic and radiologic examinations explained the origin of these gas formations. In one patient with diabetes mellitus and in another with an esophageal neoplasm, infections were caused by gas forming bacteria. In three cases, bladder fistula formations were present by Crohn's disease, colon diverticulosis and a gynecological malignancy.

  20. 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.

  1. Nile red detection of bacterial hydrocarbons and ketones in a high-throughput format.

    Science.gov (United States)

    Pinzon, Neissa M; Aukema, Kelly G; Gralnick, Jeffrey A; Wackett, Lawrence P

    2011-01-01

    A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones.

  2. 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.

  3. 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.

  4. 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

    A detailed organic geochemical study; utilising petrography, biomarker hydrocarbon analysis and high temperature GC analysis of extractable wax hydrocarbon constituents was performed on four marginally oil window-mature source rocks from the Shahejie Formation (Eocene), Damintun depression in eastern China. The main maceral components in the source rocks were vitrinite, liptinite and exinite, with vitrinite being more abundant (> 50 vol.%) in organic-lean samples whose TOC contents were between 1 and 2 wt.%. Large differences in pristanelphytane ratios suggested that the organic-rich samples were deposited in a less oxic depositional environment than that for the organic-lean rocks. The distribution of extractable wax hydrocarbons, determined by high temperature GC, showed a marked difference between these two sample types. The organic-rich samples contained high molecular weight hydrocarbons (HMWHCs) dominated by macrocrystalline n-alkanes (n-C{sub 23}-n-C{sub 37}, typically maximising at n-C{sub 29}), while the organic-lean samples contained lower amounts of extractable wax hydrocarbons but were relatively rich in microcrystalline components (> n-C{sub 35}). In all source rocks (Es3 and Es4), a noticeable odd-over-even predominance (OEP) of n-alkane chain lengths (up to n-C{sub 65}) was evident, consistent with a direct biological origin for the long n-alkyl chains. They were most probably formed during diagenesis from decarboxylation of predominantly even-carbon-numbered aliphatic acids originating from higher plant or lacustrine algal sources and/or were directly biosynthesised in hydrocarbon form. At least two other homologous series of branched/cyclic HMWHCs were observed, one of which was confirmed as a series of branched alkanes (probably methyl-branched). The carbon number distribution patterns of HMWHCs may be primarily controlled by thermal maturity and biogenic source input as well as being influenced by diagenetic reactions governed by depositional

  5. Role of minerals in formation of hydrocarbons during pyrolysis of organic matter - a material balance approach

    Energy Technology Data Exchange (ETDEWEB)

    Tannenbaum, E.; Huizinga, B.J.; Kaplan, I.R.

    1985-02-01

    Monterey Formation and Green River Formation kerogens (types II and I, respectively) were isolated, mixed with common sedimentary minerals, and pyrolyzed under dry and hydrous conditions for various times and temperatures. Analysis of all the pyrolyses products were conducted to perform a material balance and to infer reaction kinetics and mechanisms. Material balance of the pyrolyses products, in the presence and absence of minerals, reveals that the kerogen degradation results in the formation of bitumen rich in high molecular weight compounds in the initial stages, followed by additional cracking of kerogen and bitumen. However, amount and type of hydrocarbons in the pyrolyses products of kerogen in the presence of montmorillonite are markedly different from those produced by heating kerogen alone or with other minerals. The initial amounts of products in the presence of montmorillonite, and in particular the quantities of low molecular weight hydrocarbons, are higher than those in the presence of illite, calcite, and kerogen alone. The composition of these low molecular weight compounds is dominated by branched hydrocarbons, indicating catalytic cracking via carbonium ion mechanism, which is initiated on acidic sites of the clay. Composition differences are evident also in the distribution of n-alkanes and in the pristane/phytane ratio. The catalytic effect of montmorillonite, however, disappears in the presence of excess water. These differences may have important implications for the composition and quantities of petroleum generated from source rocks with different mineralogies.

  6. Separation of water through gas hydrate formation

    DEFF Research Database (Denmark)

    Boch Andersen, Torben; Thomsen, Kaj

    2009-01-01

    Gas hydrate is normally recognized as a troublemaker in the oil and gas industry. However, gas hydrate has some interesting possibilities when used in connection with separation of water. Nordic Sugar has investigated the possibility of using gas hydrates for concentration of sugar juice. The goa...... volumes and the needs for high pressure. The process could be interesting for concentration of heat sensitive, high value products......Gas hydrate is normally recognized as a troublemaker in the oil and gas industry. However, gas hydrate has some interesting possibilities when used in connection with separation of water. Nordic Sugar has investigated the possibility of using gas hydrates for concentration of sugar juice. The goal...... of the project was to formulate an alternative separation concept, which can replace the traditional water evaporation process in the sugar production. Work with the separation concept showed that gas hydrates can be used for water separation. The process is not suitable for sugar production because of large...

  7. Evaluation of the geological relationships to gas hydrate formation and stability. Progress report, June 16--September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Krason, J.; Finley, P.

    1988-12-31

    The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

  8. Kinetics of Hydrocarbon formation in a-C:H film deposition plasmas

    Energy Technology Data Exchange (ETDEWEB)

    De la Cal, E.; Tabares, F.L.

    1993-07-01

    The formation of C{sub 2} and C{sub 3} hydrocarbons during the PACVD of a-C-H films from admixtures of methane with H{sub 2} and He has been investigated by mass espectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanism of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the carburized metal. (Author)

  9. FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR GROWTH TO SOOT -A REVIEW OF CHEMICAL REACTION PATHWAYS. (R824970)

    Science.gov (United States)

    The generation by combustion processes of airborne species of current health concern such as polycyclic aromatic hydrocarbons (PAH) and soot particles necessitates a detailed understanding of chemical reaction pathways responsible for their formation. The present review discus...

  10. 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.)

  11. N2Vision technology application for direct identification of commercial hydrocarbons in Trenton-Black River Formations of Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Agou, S. [Productive Geoscience Exploration Inc., Whitby, ON (Canada)

    2006-07-01

    N2Vision seismic signal interpretation technology has been used to evaluate the petroleum and natural gas potential in the Trenton-Black River (TBR) formations of Ontario. The technology was developed in Russia in the 1980s to solve complex problems in frontier exploration. The N2Vision neural networks algorithm is a multilayer feed-forward neural network (MFFN) for pattern recognition and is based on data from existing wells collected over 20 years of method application. The algorithm recognizes hydrocarbons by establishing relationships between all attributes of the seismic field and data from existing wells. In Ontario, the algorithm was trained on data from many productive and non-productive wells from the researched and adjacent fields, as well as on seismic patterns of geological features obtained from the Yurubchen-Tokhom oil field in easter Siberia. The 2D seismic data was collected by different companies. It targeted shallower horizons and had non-consistent quality. The results of N2Vision were shown to be well correlated with the objective data. The common geological features of southern Ontario, Yurubchen field and the Baltic Syneclise were presented in this paper. All 3 regions are found in specific geodynamically prestressed and heated up zones that are represented primarily by shallow carbonates, leaching dolomites and highly permeable reservoirs with vertical fracturing. This paper demonstrated that the technology can greatly reduce the risk of selecting drilling locations, while significantly decreasing the cost of hydrocarbon exploration. tabs., figs.

  12. Formation of abnormal high pressure and its application in the study of oil-bearing property of lithologic hydrocarbon reservoirs in the Dongying Sag

    Institute of Scientific and Technical Information of China (English)

    ZHANG ShanWen; ZHANG LinYe; ZHANG ShouChun; LIU Qing; ZHU RiFang; BAO YouShu

    2009-01-01

    The mechanisms of abnormal high pressures are studied in this paper, and it is concluded that the undercompaction, hydrocarbon generation and stratum denudation are obviously effective to fluid pressure buildup. Because of the episodic difference, the hydrocarbon generation and stratum denu-dation are the main factors influencing oil-gas migration. On the basis of basin evolutionary analysis in the Dongying Sag, it is considered that the undercompaction mainly caused the abnormal pressure before the first denudation by the uplift in Late Paleogene, while hydrocarbon generation was the main factor of abnormal pressure after the denudation. The second denudation occurred in Late Neogene, which changed the pressure field and induced the fluid migration. The development of overpressures is the necessary condition to the formation of lithologic hydrocarbon reservoirs, which have positive correlations to overpressures. According to the fullness of the present reservoirs, the quantitative re-lations between oil-bearing property and driving forces of reservoir formation were determined, the latter were decided by dynamic source, reservoir capillary pressure, fluid pressure of surrounding rocks and the dynamic attenuation in different conducting systems.

  13. INFLUENCE OF CHEMICAL ADDITIVES ON GAS HYDRATE FORMATION

    Institute of Scientific and Technical Information of China (English)

    TANG Cuiping; FAN Shuanshi

    2003-01-01

    One surfactant as sodium dodecyl sulfate (SDS) and one synthesized sample as gas hydrate inhibitor are introduced in this paper. Through experiments we prove sodium dodecyl sulfate can accelerate the formation rate of gas hydrate and the synthesized sample can inhibit the formation and growth.

  14. 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...

  15. The controlling factors and distribution prediction of H2S formation in marine carbonate gas reservoir, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Generally, there are some anhydrites in carbonate reservoir, as H2S is also familiar in carbonate oil and gas reservoirs. Nowadays, natural gas with high H2S concentration is usually considered as TSR origin,so there is close relationship between H2S and anhydrite. On the contrary, some carbonate rocks with anhydrite do not contain H2S. Recently, researches show that H2S isonly a necessary condition of H2S formation. The reservoir porosity, sulfate ion content within formation water, reservoir temperature,oil/gas and water interface, hydrocarbon and some elements of reservoir rock have great controlling effects on the TSR occurrence. TSR deoxidizes hydrocarbon into the acidic gas such as H2S and CO2,and the H2S formation is controlled by TSR occurrence, so the relationship among reaction room, the contact chance of sulfate ion and hydrocarbon, the reservoir temperature has great influence on the TSR reaction. H2S has relatively active chemical quality, so it is still controlled by the content of heavy metal ion. Good conditions of TSR reaction and H2S preservation are the prerequisite of H2S distribution prediction. This paper builds a predictive model based on the characteristic of natural gas reservoir with high H2S-bearing. In the porosity reservoir with anhydrite, the formation water is rich in sulfate and poor in heavy metal ion. Oil and gas fill and accumulate in the gas reservoir with good preservation conditions, and they suffered high temperature later, which indicates the profitable area of natural gas with high H2S-bearing.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Chemistry of polycyclic aromatic hydrocarbons formation from phenyl radical pyrolysis and reaction of phenyl and acetylene.

    Science.gov (United States)

    Comandini, A; Malewicki, T; Brezinsky, K

    2012-03-15

    An experimental investigation of phenyl radical pyrolysis and the phenyl radical + acetylene reaction has been performed to clarify the role of different reaction mechanisms involved in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) serving as precursors for soot formation. Experiments were conducted using GC/GC-MS diagnostics coupled to the high-pressure single-pulse shock tube present at the University of Illinois at Chicago. For the first time, comprehensive speciation of the major stable products, including small hydrocarbons and large PAH intermediates, was obtained over a wide range of pressures (25-60 atm) and temperatures (900-1800 K) which encompass the typical conditions in modern combustion devices. The experimental results were used to validate a comprehensive chemical kinetic model which provides relevant information on the chemistry associated with the formation of PAH compounds. In particular, the modeling results indicate that the o-benzyne chemistry is a key factor in the formation of multi-ring intermediates in phenyl radical pyrolysis. On the other hand, the PAHs from the phenyl + acetylene reaction are formed mainly through recombination between single-ring aromatics and through the hydrogen abstraction/acetylene addition mechanism. Polymerization is the common dominant process at high temperature conditions.

  3. Evaluated Enthalpies of Formation of the Stable Closed Shell C1 and C2 Chlorinated Hydrocarbons

    Science.gov (United States)

    Manion, Jeffrey A.

    2002-03-01

    Experimental data on the enthalpies of formation of chloromethanes, chloroethynes, chloroethenes, and chloroethanes are critically reviewed. Enthalpy of formation values for the C1 and C2 chlorinated hydrocarbons are highly cross-linked by various measured reaction equilibria and currently available sets of values are not internally self-consistent. It is shown that the early static bomb combustion calorimetry studies on highly chlorinated compounds generally give enthalpies of formation that are systematically more positive than later values derivable from rotating bomb combustion or equilibria studies. Those previously recommended values which were based mainly on the early static bomb work therefore need substantial revision. On the basis of more recent literature data obtained with rotating bomb combustion calorimetry, together with analyses of literature data on other reaction enthalpies and equilibria involving chlorinated hydrocarbons, an updated self-consistent set of ΔfHo[298.15 K] values for closed shell chlorinated C1 and C2 hydrocarbons (25 compounds) is recommended. Data on the enthalpies of vaporization are also reviewed and values of ΔvapH[298.15 K] and ΔvapHo[298.15 K] are recommended. The presently suggested enthalpies of formation for highly chlorinated alkenes and alkanes (particularly C2Cl4, C2HCl3, C2HCl5, and C2Cl6) are significantly (8-15 kJ mol-1) more negative than given by most previous evaluators. Values for the chloroethynes are 10-25 kJ mol-1 more positive than given in previous reviews and more limited changes are suggested for other compounds in the series.

  4. On the Role of Carbides in the Formation of Hydrocarbons from Deep Carbon

    Science.gov (United States)

    Vecht, A.

    2012-12-01

    The origin of hydrocarbons found in rocks has been a matter of dispute for over a century. Scientists of the former Soviet Union favoured an inorganic origin, while in the west an organic origin was thought the most likely. Both hypotheses may be reconciled by considering the origin of carbon compounds from the core upwards or from the Earth surface downwards. Carbides are the key to understanding the development and distribution of global carbon compounds. They are precursors in the formation of hydrocarbons. It has been estimated that the Earth's core is composed of between 2-4% carbon. It is found in metallic form and is substantially denser that the surrounding mantle. Wood has proposed that the inner core is a carbide probably iron carbide(1). This conclusion is consistent with studies of meteorites, shock waves and densities Carbides can be divided into four groups:- (a) Interstitial: -Ti, V, Cr, Zr, Nb, Hf, Ta and W. (b) Covalent:- B and Si (c) Intermediate:- Ti, V, Cr, Mn, Fe, Co and Ni. (d) Salt like:- Groups I, II, and III. Groups (a) (b) and (c) should be included as candidates for carbides found in the inner core. Such carbides are stable at high temperature and will react with water and/or oxygen to form hydrocarbons and CO or CO2 respectively., carbides can be described as examples of a 'reactive minerals' as we suggested in 2007(2). Carbides which are stable at high temperatures react with water to yield hydrocarbons. This points to an abiotic origin for a range of natural hydrocarbons. A detailed review by Cataldo(3) analysed the relevant evidence for biological vs. inorganic origins. He suggests that metal carbides when hydrolysed yield organic 'matter'. Amongst the carbides suggested are (Cr, Fe, Ni, V, Mn and Co}. These carbides are correlated to the relative abundance of these elements in the solar system. We propose similar reactions based on carbides of calcium and aluminium for the formation of methane hydrate. The reactions are expected to

  5. Natural gas hydrate formation and inhibition in gas/crude oil/aqueous systems

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Pachitsas, Stylianos; von Solms, Nicolas

    2015-01-01

    Gas hydrate formation in multi phase mixtures containing an aqueous phase (with dissolved salts), reservoir fluid (crude oil) and natural gas phase was investigated by using a standard rocking cell (RC-5) apparatus. The hydrate formation temperature was reduced in the presence of crude oils...... of the biodegradable commercial kinetic inhibitor (Luvicap-Bio) on natural gas hydrate formation with and without crude oil (30%) was investigated. The strength of kinetic inhibitor was not affected by salts, but decreased significantly in the presence of crude oil. Data for hydrate formation at practical conditions...... can contribute to the safe operation of sub sea pipelines in the oil and gas industry....

  6. Condensate formation in a Bose gas

    NARCIS (Netherlands)

    Stoof, H.T.C.

    1995-01-01

    Using magnetically trapped atomic hydrogen as an example, we investigate the prospects of achieving Bose-Einstein condensation in a dilute Bose gas. We show that, if gas is quenched sufficiently far into the critical region of the phase transition, the typical time scale for the nucleation of the co

  7. 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

  8. Evidence from SOFIA Imaging of Polycyclic Aromatic Hydrocarbon Formation along a Recent Outflow in NGC 7027

    Science.gov (United States)

    Lau, R. M.; Werner, M.; Sahai, R.; Ressler, M. E.

    2016-12-01

    We report spatially resolved (FWHM ˜ 3.″8-4.″6) mid-IR imaging observations of the planetary nebula (PN) NGC 7027 taken with the 2.5 m telescope on board the Stratospheric Observatory for Infrared Astronomy (SOFIA). Images of NGC 7027 were acquired at 6.3, 6.6, 11.1, 19.7, 24.2, 33.6, and 37.1 μ {{m}} using the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST). The observations reveal emission from polycyclic aromatic hydrocarbons (PAHs) and warm dust ({T}D˜ 90 K) from the illuminated inner edge of the molecular envelope surrounding the ionized gas and central star. The DustEM code was used to fit the spectral energy distribution of fluxes obtained by FORCAST and the archival infrared spectrum of NGC 7027 acquired by the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). Best-fit dust models provide a total dust mass of {5.8}-2.6+2.3× {10}-3 {M}⊙ , where carbonaceous large (a = 1.5 μm) and very small (a˜ 12 \\mathringA ) grains, and PAHs (3.1 \\mathringA \\lt a\\lt 12 \\mathringA ) compose 96.5, 2.2, and 1.3% of the dust by mass, respectively. The 37 μm optical depth map shows minima in the dust column density at regions in the envelope that are coincident with a previously identified collimated outflow from the central star. The optical depth minima are also spatially coincident with enhancements in the 6.2 μm PAH feature, which is derived from the 6.3 and 6.6 μm maps. We interpret the spatial anti-correlation of the dust optical depth and PAH 6.2 μm feature strength and their alignment with the outflow from the central star as evidence of dust processing and rapid PAH formation via grain-grain collisions in the post-shock environment of the dense ({n}{{H}}˜ {10}5 {{cm}}-3) photo-dissociation region and molecular envelope.

  9. Formation of H{sub 2} from internally heated polycyclic aromatic hydrocarbons: Excitation energy dependence

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se; Gatchell, M.; Stockett, M. H.; Schmidt, H. T.; Cederquist, H.; Zettergren, H., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se [Department of Physics, Stockholm University, S-106 91 Stockholm (Sweden); Delaunay, R.; Rousseau, P.; Adoui, L. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Université de Caen Basse-Normandie, Esplanade de la Paix, F-14032 Caen (France); Domaracka, A.; Huber, B. A. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Micelotta, E. R. [Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2015-04-14

    We have investigated the effectiveness of molecular hydrogen (H{sub 2}) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results are analyzed in view of molecular structure calculations and a simple collision model. We estimate that H{sub 2} formation becomes important for internal PAH temperatures exceeding about 2200 K, regardless of the PAH size and the excitation agent. This suggests that keV ions may effectively induce such reactions, while they are unlikely due to, e.g., absorption of single photons with energies below the Lyman limit. The present analysis also suggests that H{sub 2} emission is correlated with multi-fragmentation processes, which means that the [PAH-2H]{sup +} peak intensities in the mass spectra may not be used for estimating H{sub 2}-formation rates.

  10. Star Formation and Gas Accretion in Nearby Galaxies

    CERN Document Server

    Yim, Kijeong

    2016-01-01

    In order to quantify the relationship between gas accretion and star formation, we analyse a sample of 29 nearby galaxies from the WHISP survey which contains galaxies with and without evidence for recent gas accretion. We compare combined radial profiles of FUV (GALEX) and IR 24 {\\mu}m (Spitzer) characterizing distributions of recent star formation with radial profiles of CO (IRAM, BIMA, or CARMA) and HI (WSRT) tracing molecular and atomic gas contents to examine star formation efficiencies in symmetric (quiescent), asymmetric (accreting), and interacting (tidally disturbed) galaxies. In addition, we investigate the relationship between star formation rate and HI in the outer discs for the three groups of galaxies. We confirm the general relationship between gas surface density and star formation surface density, but do not find a significant difference between the three groups of galaxies.

  11. Production of a New Emulsifier Material for the Formation Heavy Hydrocarbon/Water Emulsion

    Directory of Open Access Journals (Sweden)

    Afshin Farahbakhsh

    2011-04-01

    Full Text Available Emulsifiers are a unique class of compounds that have proved to have a variety of potential applications in formation of hydrocarbon in water emulsion, in enhancement of oil recovery and in the reduction of heavy oil viscosity. In this paper, a bio emulsifier was synthesized by a strain of Bacillus licheniformis and was separated by an autoclave and centrifugal process; the purification of bio emulsifier and the increase quality of product was done by adding sulfuric acid (H2SO4 (98% to the solution and centrifuging this compound again. This bio emulsifier has the property of emulsification to a wide range of heavy hydrocarbon to form a stable hydrocarbon-water emulsion. This bio emulsifier could reduce Iranian Nuroze high viscosity oil of about 10000 cP down to 250 cP. This means about 97% decreases in the viscosity. The emulsion stable this condition for 48 hr and the viscosity slowly increases to 4000cp until 192 hr. The stability of the oil in water emulsion during 48hr allows the heavy oil to be transported practically over lengthy distances or remain stable for long periods of time prior to utilization.

  12. 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.

  13. 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.

  14. LABORATORY INVESTIGATIONS OF POLYCYCLIC AROMATIC HYDROCARBON FORMATION AND DESTRUCTION IN THE CIRCUMSTELLAR OUTFLOWS OF CARBON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Cesar S.; Salama, Farid, E-mail: cesar.contreras@nasa.gov, E-mail: Farid.Salama@nasa.gov [Space Science and Astrobiology Division, NASA-Ames Research Center, Moffett Field, CA 94035 (United States)

    2013-09-15

    The formation and destruction mechanisms of interstellar dust analogs formed from a variety of polycyclic aromatic hydrocarbon (PAH) and hydrocarbon molecular precursors are studied in the laboratory. We used the newly developed facility COSmIC, which simulates interstellar and circumstellar environments, to investigate both PAHs and species that include the cosmically abundant atoms O, N, and S. The species generated in a discharge plasma are detected, monitored, and characterized in situ using highly sensitive techniques that provide both spectral and ion mass information. We report here the first series of measurements obtained in these experiments which focus on the characterization of the most efficient molecular precursors in the chemical pathways that eventually lead to the formation of carbonaceous grains in the stellar envelopes of carbon stars. We compare and discuss the relative efficiencies of the various molecular precursors that lead to the formation of the building blocks of carbon grains. We discuss the most probable molecular precursors in terms of size and structure and the implications for the expected growth and destruction processes of interstellar carbonaceous dust.

  15. Heterogeneity of lithologically-screened hydrocarbon formations governed by carbonate concretions

    Energy Technology Data Exchange (ETDEWEB)

    Vysotskiy, V.N.; Lyudofun, F.N.; Sidorenkov, A.I.

    1979-01-01

    The complex structure of sections of thinning of bed-collectors governed by the constant presence of a lens of carbonate-terrigenous rocks is examined. It is indicated that the thinning traps have higher concretion carbonate content than the bed arc. The closer to the lateral lithological screen in the thinning traps, the more the concretion coefficient has a directed changing gradient of increase. The conclusion is drawn that this empirical law can be used at the stage of exploring hydrocarbon formations or for tracing the thinning line of the bed collector.

  16. 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.

  17. 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.

  18. A discussion on gas sources of the Feixianguan Formation H2S-rich giant gas fields in the northeastern Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years several H2S-rich oolite giant gas pools have been discovered in the Lower Triassic Feixianguan Formation of the northeastern Sichuan basin, and their explored gas reserves have been over 5000x108 m3. However, gas sources remain unsolved due to multiple source horizons with high maturity in this area and TSR alterations. By integrating analytical data of natural gas samples with conprehensive investigations on many factors, such as oil-gas geology, distribution and evolution of source rocks, charging and adjustment of gas pools, mixture of natural gases and secondery alterations, the present study concluded that the dominant source for the Feixianguan Fr. gas pools is the Permian Longtan Fr. source rock and secondly the Silurian Longmaxi Fr. source rock. Natural gases from the various gas pools differ genetically due to the matching diversity of seal configurations with phases of hydrocarbon generation and expulsion by different source rocks, among which natural gases in Puguang Gasfield are dominated by the trapped gas generated from the Longtan Fr. source rock and commingled with the gas cracked from the Silurian crude oil, while those in Dukouhe,Tieshangpo and Luojiazhai Gasfields are composed mainly of the Silurian oil-cracking gas and commingled with the natural gas derived from the Longtan Fr. source rock.

  19. Role of temperature and hydrochloric acid on the formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons during combustion of paraffin powder, polymers, and newspaper.

    Science.gov (United States)

    Takasuga, Takumi; Umetsu, Norihito; Makino, Tetsuya; Tsubota, Katsuya; Sajwan, Kenneth S; Kumar, Kurunthachalam Senthil

    2007-07-01

    Formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were determined using a laboratory-scale incinerator when combusting materials at different temperatures, different concentrations of hydrochloric acid (HCl), and when combusting various types of polymers/newspaper. Polychlorobenzenes (PCBz), polychlorophenols (PCPhs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and their toxic equivalency (TEQ) and PAHs were highlighted and reported. Our results imply maximum formation of chlorinated hydrocarbons at 400 degrees C in the following order; PCBz>or=PCPhs>PCDFs>PCDDs>TEQ on a parts-per-billion level. Similarly, a maximum concentration of chlorinated hydrocarbons was noticed with an HCl concentration at 1000 ppm with the presence of paraffin powder in the following order; PAHs>PCBz>or=PCPhs>PCDFs>PCDDs>TEQ an a parts-per-billion level. PAHs were not measured at different temperatures. Elevated PAHs were noticed with different HCl concentrations and paraffin powder combustion (range: 27-32 microg/g). While, different polymers and newspaper combusted, nylon and acrylonitrile butadiene styrene (ABS) produced the maximum hydrogen cyanide (HCN) concentration, concentrations of PCDD/FS, dioxin-like polychlorinated biphenyls (DL-PCBs), and TEQ were in a decreasing order: polyvinylchloride (PVC)newspapernewspapernewspaper newspapernewspaper

  20. Control of coupling among three major factors for formation of high-efficiency gas reservoir——A case study on the oolitic beach gas reservoir in Feixianguan Formation in the northeast Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Through a case study of the high-efficiency gas reservoir in Feixianguan Formation in the northeast Sichuan Basin, quantitative and semi-quantitative analyses of key elements such as hydrocarbon generation, migration and accumulation, and reservoir evolution as well as their interplay in the critical moment of reservoir formation controlled by the energy field were carried out, by means of numerical modeling of the energy field. It was found that the climax time for Permian hydrocarbon generation was Late Triassic-Early Jurassic and accumulation of oil and gas has resulted in large-scale paleoreservoirs in paleostructural traps in Feixianguan Formation, a process facilitated by fractures connecting the sources. The paleoreservoirs have been turned into high-efficiency gas kitchens due to pyrolysis,which resulted from deep burial at a temperature of 170-210℃ as induced by tremendously thick sedimentation in the foreland basin of Daba Mountain in Late Jurassic-Cretaceous period. Meanwhile,abundant acid gas like H2S produced from thermo-chemical sulfate reduction (TSR) at high temperatures leads to extensive dissolution of dolostone in the paleoreservoirs, which may in turn result in modification of the reservoirs and preservation of the reservoir rock porosity. The present distribution of gas reservoirs was ultimately determined in the processes of adjustment, cooling and decompression of the paleoreservoirs resulting from intense deformation in the front of Daba Mountain during the Himalayan orogeny.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.)

  7. Star Formation in Turbulent Interstellar Gas

    CERN Document Server

    Klessen, R S

    2003-01-01

    Understanding the star formation process is central to much of modern astrophysics. For several decades it has been thought that stellar birth is primarily controlled by the interplay between gravity and magnetostatic support, modulated by ambipolar diffusion. Recently, however, both observational and numerical work has begun to suggest that supersonic interstellar turbulence rather than magnetic fields controls star formation. Supersonic turbulence can provide support against gravitational collapse on global scales, while at the same time it produces localized density enhancements that allow for collapse on small scales. The efficiency and timescale of stellar birth in Galactic molecular clouds strongly depend on the properties of the interstellar turbulent velocity field, with slow, inefficient, isolated star formation being a hallmark of turbulent support, and fast, efficient, clustered star formation occurring in its absence.

  8. Modeling biogenic gas bubbles formation and migration in coarse sand

    Science.gov (United States)

    Ye, S.

    2011-12-01

    Shujun Ye Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China; sjye@nju.edu.cn Brent E. Sleep Department of Civil Engineering, University of Toronto, Toronto, ON, M5S 1A4 CANADA; sleep@ecf.utoronto.ca Methane gas generation in porous media was investigated in an anaerobic two-dimensional sand-filled cell. Inoculation of the lower portion of the cell with a methanogenic culture and addition of methanol to the bottom of the cell led to biomass growth and formation of a gas phase. The formation, migration, distribution and saturation of gases in the cell were visualized by the charge-coupled device (CCD) camera. Gas generated at the bottom of the cell in the biologically active zone moved upwards in discrete fingers, so that gas phase saturations (gas-filled fraction of void space) in the biologically active zone at the bottom of the cell did not exceed 40-50%, while gas accumulation at the top of the cell produced gas phase saturations as high as 80%. Macroscopic invasion percolation (MIP) at near pore scale[Glass, et al., 2001; Kueper and McWhorter, 1992]was used to model gas bubbles growth in porous media. The nonwetting phase migration pathway can be yielded directly by MIP. MIP was adopted to simulate the expansion, fragmentation, and mobilization of gas clusters in the cell. The production of gas, and gas phash saturations were simulated by a continuum model - compositional simulator (COMPSIM) [Sleep and Sykes, 1993]. So a combination of a continuum model and a MIP model was used to simulate the formation, fragmentation and migration of biogenic gas bubbles. Key words: biogenic gas; two dimensional; porous media; MIP; COMPSIM

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. Impact of molecular structure on secondary organic aerosol formation from aromatic hydrocarbon photooxidation under low-NOx conditions

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Cocker, David R., III

    2016-08-01

    The molecular structure of volatile organic compounds determines their oxidation pathway, directly impacting secondary organic aerosol (SOA) formation. This study comprehensively investigates the impact of molecular structure on SOA formation from the photooxidation of 12 different eight- to nine-carbon aromatic hydrocarbons under low-NOx conditions. The effects of the alkyl substitute number, location, carbon chain length and branching structure on the photooxidation of aromatic hydrocarbons are demonstrated by analyzing SOA yield, chemical composition and physical properties. Aromatic hydrocarbons, categorized into five groups, show a yield order of ortho (o-xylene and o-ethyltoluene) > one substitute (ethylbenzene, propylbenzene and isopropylbenzene) > meta (m-xylene and m-ethyltoluene) > three substitute (trimethylbenzenes) > para (p-xylene and p-ethyltoluene). SOA yields of aromatic hydrocarbon photooxidation do not monotonically decrease when increasing alkyl substitute number. The ortho position promotes SOA formation while the para position suppresses aromatic oxidation and SOA formation. Observed SOA chemical composition and volatility confirm that higher yield is associated with further oxidation. SOA chemical composition also suggests that aromatic oxidation increases with increasing alkyl substitute chain length and branching structure. Further, carbon dilution conjecture developed by Li et al. (2016) is extended in this study to serve as a standard method to determine the extent of oxidation of an alkyl-substituted aromatic hydrocarbon.

  15. Calorimetric Determination of Enthalpy of Formation of Natural Gas Hydrates

    Institute of Scientific and Technical Information of China (English)

    高军; KennethN.Marsh

    2003-01-01

    This paper reports the measurements of enthalpies of natural gas hydrates in typical natural gas mixture containing methane, ethane, propane and iso-butane at pressure in the vicinity of 2000 kPa (300 psi) and 6900 kPa(1000psi). The measurements were made in a multi-cell differential scanning calorimeter using modified high pressure cells. The enthalpy of water and the enthalpy of dissociation of the gas hydrate were determined from the calorimeter response during slow temperature scanning at constant pressure. The amount of gas released from the dissociation of hydrate was determined from the pumped volume of the high pressure pump. The occupation ratio (mole ratio) of the water to gas and the enthalpy of hydrate formation are subject to uncertainty of 1.5%.The results show that the enthalpy of hydrate formation and the occupation ratio are essentially independent of pressure.

  16. 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

  17. Formation of Secondary Particulate Matter by Reactions of Gas Phase Hexanal with Sulfate Aerosol Particles

    Science.gov (United States)

    Zhang, J.

    2003-12-01

    The formation of secondary particulate matter from the atmospheric oxidation of organic compounds can significantly contribute to the particulate burden, but the formation of organic secondary particulate matter is poorly understood. One way of producing organic secondary particulate matter is the oxidation of hydrocarbons with seven or more carbon atoms to get products with low vapor pressure. However, several recent reports suggest that relatively low molecular weight carbonyls can enter the particle phase by undergoing heterogeneous reactions. This may be a very important mechanism for the formation of organic secondary particulate matter. Atmospheric aldehydes are important carbonyls in the gas phase, which form via the oxidation of hydrocarbons emitted from anthropogenic and biogenic sources. In this poster, we report the results on particle growth by the heterogeneous reactions of hexanal. A 5 L Continuous Stirred Tank Reactor (CSTR) is set up to conduct the reactions in the presence of seed aerosol particles of deliquesced ammonia bisulfate. Hexanal is added into CSTR by syringe pump, meanwhile the concentrations of hexanal are monitored with High Pressure Liquid Chromatograph (HPLC 1050). A differential Mobility Analyzer (TSI 3071) set to an appropriate voltage is employed to obtain monodisperse aerosols, and another DMA associated with a Condensation Nuclear Counter (TSI 7610) is used to measure the secondary particle size distribution by the reaction in CSTR. This permits the sensitive determination of particle growth due to the heterogeneous reaction, very little growth occurs when hexanal added alone. Results for the simultaneous addition of hexanal and alcohols will also be presented.

  18. Hydrocarbon potential evaluation of the source rocks from the Abu Gabra Formation in the Sufyan Sag, Muglad Basin, Sudan

    Science.gov (United States)

    Qiao, Jinqi; Liu, Luofu; An, Fuli; Xiao, Fei; Wang, Ying; Wu, Kangjun; Zhao, Yuanyuan

    2016-06-01

    The Sufyan Sag is one of the low-exploration areas in the Muglad Basin (Sudan), and hydrocarbon potential evaluation of source rocks is the basis for its further exploration. The Abu Gabra Formation consisting of three members (AG3, AG2 and AG1 from bottom to top) was thought to be the main source rock formation, but detailed studies on its petroleum geology and geochemical characteristics are still insufficient. Through systematic analysis on distribution, organic matter abundance, organic matter type, organic matter maturity and characteristics of hydrocarbon generation and expulsion of the source rocks from the Abu Gabra Formation, the main source rock members were determined and the petroleum resource extent was estimated in the study area. The results show that dark mudstones are the thickest in the AG2 member while the thinnest in the AG1 member, and the thickness of the AG3 dark mudstone is not small either. The AG3 member have developed good-excellent source rock mainly with Type I kerogen. In the Southern Sub-sag, the AG3 source rock began to generate hydrocarbons in the middle period of Bentiu. In the early period of Darfur, it reached the hydrocarbon generation and expulsion peak. It is in late mature stage currently. The AG2 member developed good-excellent source rock mainly with Types II1 and I kerogen, and has lower organic matter abundance than the AG3 member. In the Southern Sub-sag, the AG2 source rock began to generate hydrocarbons in the late period of Bentiu. In the late period of Darfur, it reached the peak of hydrocarbon generation and its expulsion. It is in middle mature stage currently. The AG1 member developed fair-good source rock mainly with Types II and III kerogen. Throughout the geological evolution history, the AG1 source rock has no effective hydrocarbon generation or expulsion processes. Combined with basin modeling results, we have concluded that the AG3 and AG2 members are the main source rock layers and the Southern Sub-sag is

  19. Prediction of natural gas hydrate formation region in wellbore during deep- water gas well testing

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-yuan; SUN Bao-jiang; WANG Xue-rui; ZHANG Zhen-nan

    2014-01-01

    Wellbore temperature field equations are established with considerations of the enthalpy changes of the natural gas during the deep-water gas well testing. A prediction method for the natural gas hydrate formation region during the deep-water gas well testing is proposed, which combines the wellbore temperature field equations, the phase equilibrium conditions of the natural gas hydrate formation and the calculation methods for the pressure field. Through the sensitivity analysis of the parameters that affect the hydrate formation region, it can be concluded that during the deep-water gas well testing, with the reduction of the gas production rate and the decrease of the geothermal gradient, along with the increase of the depth of water, the hydrate formation region in the wellbore enlarges, the hydrate formation regions differ with different component contents of natural gases, as compared with the pure methane gas, with the increase of ethane and propane, the hydrate formation region expands, the admixture of inhibitors, the type and the concentrations of which can be optimized through the method proposed in the paper, will reduce the hydrate formation region, the throttling effect will lead to the abrupt changes of temperature and pressure, which results in a variation of the hydrate formation region, if the throttling occurs in the shallow part of the wellbore, the temperature will drop too much, which enlarges the hydrate formation region, otherwise, if the throttling occurs in the deep part of the wellbore, the hydrate formation region will be reduced due to the decrease of the pressure.

  20. Formation of PAHs and Carbonaceous Solids in Gas-Phase Condensation Experiments

    CERN Document Server

    Jäger, C; Jansa, I Llamas; Henning, T; Huisken, F

    2009-01-01

    Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs), that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile 3-5 ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot AGB stars or W...

  1. Polycyclic aromatic hydrocarbon (PAH) formation from benzyl radicals: a reaction kinetics study.

    Science.gov (United States)

    Sinha, Sourab; Raj, Abhijeet

    2016-03-21

    The role of resonantly stabilized radicals such as propargyl, cyclopentadienyl and benzyl in the formation of aromatic hydrocarbons such as benzene and naphthalene in the high temperature environments has been long known. In this work, the possibility of benzyl recombination to form three-ring aromatics, phenanthrene and anthracene, is explored. A reaction mechanism for it is developed, where reaction energetics are calculated using density functional theory (B3LYP functional with 6-311++G(d,p) basis set) and CBS-QB3, while temperature-dependent reaction kinetics are evaluated using transition state theory. The mechanism begins with barrierless formation of bibenzyl from two benzyl radicals with the release of 283.2 kJ mol(-1) of reaction energy. The further reactions involve H-abstraction by a H atom, H-desorption, H-migration, and ring closure to gain aromaticity. Through mechanism and rate of production analyses, the important reactions leading to phenanthrene and anthracene formation are determined. Phenanthrene is found to be the major product at high temperatures. Premixed laminar flame simulations are carried out by including the proposed reactions for phenanthrene formation from benzyl radicals and compared to experimentally observed species profiles to understand their effects on species concentrations.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. A prediction method of natural gas hydrate formation in deepwater gas well and its application

    Directory of Open Access Journals (Sweden)

    Yanli Guo

    2016-09-01

    Full Text Available To prevent the deposition of natural gas hydrate in deepwater gas well, the hydrate formation area in wellbore must be predicted. Herein, by comparing four prediction methods of temperature in pipe with field data and comparing five prediction methods of hydrate formation with experiment data, a method based on OLGA & PVTsim for predicting the hydrate formation area in wellbore was proposed. Meanwhile, The hydrate formation under the conditions of steady production, throttling and shut-in was predicted by using this method based on a well data in the South China Sea. The results indicate that the hydrate formation area decreases with the increase of gas production, inhibitor concentrations and the thickness of insulation materials and increases with the increase of thermal conductivity of insulation materials and shutdown time. Throttling effect causes a plunge in temperature and pressure in wellbore, thus leading to an increase of hydrate formation area.

  7. 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

  8. Methane Conversion to C2 Hydrocarbons Using Glow Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Miao; CHEN Jierong

    2007-01-01

    The infrared emission spectra of methane, H', CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.

  9. 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.

  10. A New Star-Formation Rate Calibration from Polycyclic Aromatic Hydrocarbon Emission Features and Application to High Redshift Galaxies

    CERN Document Server

    Shipley, Heath V; Rieke, George H; Brown, Michael J I; Moustakas, John

    2016-01-01

    We calibrate the integrated luminosity from the polycyclic aromatic hydrocarbon (PAH) features at 6.2\\micron, 7.7\\micron\\ and 11.3\\micron\\ in galaxies as a measure of the star-formation rate (SFR). These features are strong (containing as much as 5-10\\% of the total infrared luminosity) and suffer minimal extinction. Our calibration uses \\spitzer\\ Infrared Spectrograph (IRS) measurements of 105 galaxies at $0 < z < 0.4$, infrared (IR) luminosities of $10^9 - 10^{12} \\lsol$, combined with other well-calibrated SFR indicators. The PAH luminosity correlates linearly with the SFR as measured by the extinction-corrected \\ha\\ luminosity over the range of luminosities in our calibration sample. The scatter is 0.14 dex comparable to that between SFRs derived from the \\paa\\ and extinction-corrected \\ha\\ emission lines, implying the PAH features may be as accurate a SFR indicator as hydrogen recombination lines. The PAH SFR relation depends on gas-phase metallicity, for which we supply an empirical correction for...

  11. 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

  12. Methods of producing alkylated hydrocarbons from an in situ heat treatment process liquid

    Science.gov (United States)

    Roes, Augustinus Wilhelmus Maria; Mo, Weijian; Muylle, Michel Serge Marie; Mandema, Remco Hugo; Nair, Vijay

    2009-09-01

    A method for producing alkylated hydrocarbons is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce at least a second gas stream including hydrocarbons having a carbon number of at least 3. The first gas stream and the second gas stream are introduced into an alkylation unit to produce alkylated hydrocarbons. At least a portion of the olefins in the first gas stream enhance alkylation.

  13. Geology and hydrocarbon potential of Dawson Bay Formation carbonate unit (Middle Devonian), Williston basin, North Dakota

    Energy Technology Data Exchange (ETDEWEB)

    Pound, W.

    1988-07-01

    The Middle Devonian Dawson Bay Formation carbonate unit is present in the subsurface of North Dakota except where truncated by postdepositional erosion. The carbonate unit thickens from the erosional limit to a maximum thickness of 47.5 m (156 ft) in Renville County and reaches a maximum depth of 3798 m (12,460 ft) below the surface in McKenzie County. In North Dakota, a submarine hardground separates the carbonate unit from the underlying second red bed member of the Dawson Bay Formation. The upper contact with the Souris River Formation is conformable except in those areas where the Dawson Bay Formation was exposed to subaerial erosion prior to deposition of the Souris River sediments. The Dawson Bay carbonate unit is predominantly dolomitic and fossiliferous limestone or fossiliferous dolostone. The carbonate unit can be subdivided into five lithofacies on the basis of characteristic fossil fauna, flora, and other lithologic features. Lithofacies analysis of the Dawson Bay carbonates suggests a shallowing-upward succession of depositional environments and associated energy zones as follows: shallow epeiric sea (very low energy), stromatoporoid biostrome/bioherm (low energy), very shallow epeiric sea (very low energy), restricted shallow epeiric sea (extremely low energy), and shallow epeiric sea shoreline (variable energy). Eogenetic diagenesis includes color-mottling, dolomitization of micrite to microcrystalline dolomite with penecontemporaneous anhydrite replacement of cryptalgal mudstones and boundstones, cementation by sparry calcite, and vuggy porosity development. Mesogenetic diagenesis includes formation of mosaic dolomites, cementation by blocky equant calcite, neomorphism, pressure-solution, fracturing, halite cementation, and hydrocarbon emplacement.

  14. 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.

  15. Gas hydrate, fluid flow and free gas: Formation of the bottom-simulating reflector

    Science.gov (United States)

    Haacke, R. Ross; Westbrook, Graham K.; Hyndman, Roy D.

    2007-09-01

    Gas hydrate in continental margins is commonly indicated by a prominent bottom-simulating seismic reflector (BSR) that occurs a few hundred metres below the seabed. The BSR marks the boundary between sediments containing gas hydrate above and free gas below. Most of the reflection amplitude is caused by the underlying free gas. Gas hydrate can occur without a BSR, however, and the controls on its formation are not well understood. Here we describe two complementary mechanisms for free gas accumulation beneath the gas hydrate stability zone (GHSZ). The first is the well-recognised hydrate recycling mechanism that generates gas from dissociating hydrate when the base of the GHSZ moves upward relative to hydrate-bearing sediment. The second is a recently identified mechanism in which the relationship between the advection and diffusion of dissolved gas with the local solubility curve allows the liquid phase to become saturated in a thick layer beneath the GHSZ when hydrate is present near its base. This mechanism for gas production (called the solubility-curvature mechanism) is possible in systems where the influence of diffusion becomes important relative to the influence of advection and where the gas-water solubility decreases to a minimum several hundred metres below the GHSZ. We investigate a number of areas in which gas hydrate occurs to determine where gas formation is dominated by the solubility-curvature mechanism and where it is dominated by hydrate recycling. We show that the former is dominant in areas with low rates of upward fluid flow (such as old, rifted continental margins), low rates of seafloor uplift, and high geothermal gradient and/or pressure. Conversely, free-gas formation is dominated by hydrate recycling where there are rapid rates of upward fluid flow and seabed uplift (such as in subduction zone accretionary wedges). Using these two mechanisms to investigate the formation of free gas beneath gas hydrate in continental margins, we are able

  16. Gas accretion on spiral galaxies bar formation and renewal

    CERN Document Server

    Bournaud, F

    2002-01-01

    The effects of gas accretion on spiral disk dynamics and stability are studied through N-body simulations, including star formation and gas/stars mass exchange. The detailed processes of bar formation, bar destruction and bar re-formation are followed, while in the same time the disk to bulge ratio is varying. The accreted gas might be first prevented to flow inwards to the center by the bar gravity torques, which maintains it to the outer Lindblad resonance. While the first bar is weakening, the accreted gas replenishes the disk, increasing the disk-to-bulge ratio, and the disk self-gravity. A second bar is then unstable, with a higher pattern speed, due both to the increased mass, and shorter bar length. Three or four bar episodes have been followed over a Hubble time. Their strength is decreasing with time, while their pattern speed is increasing. Detailed balance of the angular momentum transfer and evolution can account for these processes. The gas recycled through star formation, and rejected through st...

  17. 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.

  18. 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.

  19. Measuring Star-Formation Rates of AGNs and QSOs using a new calibration from Polycyclic Aromatic Hydrocarbon Emission

    Science.gov (United States)

    Papovich, Casey

    Understanding the coevolution of star-formation and supermassive black hole accretion is one of the key questions in galaxy formation theory. This relation is important for understanding why at present the mass in galaxy bulges (on scales of kpc) correlates so tightly with the mass of galaxy central supermassive blackholes (on scales of AU). Feedback from supermassive black hole accretion may also be responsible for heating or expelling cold gas from galaxies, shutting off the fuel for star-formation and additional black hole growth. Did bulges proceed the formation of black holes, or vice versa, or are they contemporaneous? Therefore, understanding the exact rates of star-formation and supermassive black hole growth, and how they evolve with time and galaxy mass has deep implications for how galaxies form. It has previously been nearly impossible to study simultaneously both star-formation and accretion onto supermassive black holes in galaxies because the emission from black hole accretion contaminates nearly all diagnostics of star-formation. The "standard" diagnostics for the star-formation rate (the emission from hydrogen, UV emission, midIR emission, far-IR emission, etc) are not suitable for measuring star-formation rates in galaxies with actively accreting supermassive blackholes. In this proposal, the researchers request NASA/ADP funding for an archival study using spectroscopy with the Spitzer Space Telescope to measure simultaneously the star-formation rate (SFR) and bolometric emission from accreting supermassive blackholes to understand the complex relation between both processes. The key to this study is that they will develop a new calibrator for SFRs in galaxies with active supermassive black holes based on the molecular emission from polycyclic aromatic hydrocarbons (PAHs), which emit strongly in the mid-IR (3 - 20 micron) and are very strong in spectra from the Spitzer Space Telescope. The PAH molecules exist near photo-dissociation regions, and

  20. 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.

  1. 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.

  2. Jet formation in shock-heavy gas bubble interaction

    Institute of Scientific and Technical Information of China (English)

    Zhi-Gang Zhai; Ting Si; Li-Yong Zou; Xi-Sheng Luo

    2013-01-01

    The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work.The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D.As a validation,the experiments of a SF6 bubble accelerated by a planar shock were performed.The results indicate that,due to the mismatch of acoustic impedance,the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition.With respect to the same bubble,the manner of jet formation is also distinctly different under different shock strengths.The disparities of the acoustic impedance result in different effects of shock focusing in the bubble,and different behaviors of shock wave inside and outside the bubble.The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation.Moreover,the analysis of the vorticity deposition,and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation.It is concluded that the pressure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

  3. 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.

  4. On the Formation of Nanobubbles in Vycor Porous Glass during the Desorption of Halogenated Hydrocarbons

    Science.gov (United States)

    Mitropoulos, A. C.; Stefanopoulos, K. L.; Favvas, E. P.; Vansant, E.; Hankins, N. P.

    2015-06-01

    Vycor porous glass has long served as a model mesoporous material. During the physical adsorption of halogenated hydrocarbon vapours, such as dibromomethane, the adsorption isotherm exhibits an hysteresis loop; a gradual ascent is observed at higher pressures during adsorption, and a sharp drop is observed at lower pressures during desorption. For fully wetting fluids, an early hypothesis attributed the hysteresis to mechanistic differences between capillary condensation (adsorption) and evaporation (desorption) processes occurring in the wide bodies and narrow necks, respectively, of ‘ink-bottle’ pores. This was later recognized as oversimplified when the role of network percolation was included. For the first time, we present in-situ small angle x-ray scattering measurements on the hysteresis effect which indicate nanobubble formation during desorption, and support an extended picture of network percolation. The desorption pattern can indeed result from network percolation; but this can sometimes be initiated by a local cavitation process without pore blocking, which is preceded by the temporary, heterogeneous formation of nanobubbles involving a change in wetting states. The capacity of the system to sustain such metastable states is governed by the steepness of the desorption boundary.

  5. Organic substances in produced and formation water from unconventional natural gas extraction in coal and shale

    Science.gov (United States)

    Orem, William H.; Tatu, Calin A.; Varonka, Matthew S.; Lerch, Harry E.; Bates, Anne L.; Engle, Mark A.; Crosby, Lynn M.; McIntosh, Jennifer

    2014-01-01

    Organic substances in produced and formation water from coalbed methane (CBM) and gas shale plays from across the USA were examined in this study. Disposal of produced waters from gas extraction in coal and shale is an important environmental issue because of the large volumes of water involved and the variable quality of this water. Organic substances in produced water may be environmentally relevant as pollutants, but have been little studied. Results from five CBM plays and two gas shale plays (including the Marcellus Shale) show a myriad of organic chemicals present in the produced and formation water. Organic compound classes present in produced and formation water in CBM plays include: polycyclic aromatic hydrocarbons (PAHs), heterocyclic compounds, alkyl phenols, aromatic amines, alkyl aromatics (alkyl benzenes, alkyl biphenyls), long-chain fatty acids, and aliphatic hydrocarbons. Concentrations of individual compounds range from organic carbon (TOC) in CBM produced water is generally in the 1–4 mg/L range. Excursions from this general pattern in produced waters from individual wells arise from contaminants introduced by production activities (oils, grease, adhesives, etc.). Organic substances in produced and formation water from gas shale unimpacted by production chemicals have a similar range of compound classes as CBM produced water, and TOC levels of about 8 mg/L. However, produced water from the Marcellus Shale using hydraulic fracturing has TOC levels as high as 5500 mg/L and a range of added organic chemicals including, solvents, biocides, scale inhibitors, and other organic chemicals at levels of 1000 s of μg/L for individual compounds. Levels of these hydraulic fracturing chemicals and TOC decrease rapidly over the first 20 days of water recovery and some level of residual organic contaminants remain up to 250 days after hydraulic fracturing. Although the environmental impacts of the organics in produced water are not well defined, results

  6. EXPERIMENTAL EVIDENCE FOR THE FORMATION OF HIGHLY SUPERHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS THROUGH H ATOM ADDITION AND THEIR CATALYTIC ROLE IN H{sub 2} FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Thrower, J. D.; Jorgensen, B.; Friis, E. E.; Baouche, S.; Luntz, A. C.; Andersen, M.; Hammer, B.; Hornekaer, L. [Department of Physics and Astronomy and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Mennella, V., E-mail: thrower@phys.au.dk [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli (Italy)

    2012-06-10

    Mass spectrometry measurements show the formation of highly superhydrogenated derivatives of the polycyclic aromatic hydrocarbon molecule coronene through H atom addition reactions. The observed product mass distribution provides evidence also for abstraction reactions resulting in H{sub 2} formation, in agreement with recent IR measurements. Complementary density functional theory calculations confirm the stability of the observed superhydrogenated species toward spontaneous H and H{sub 2} loss indicating that abstraction reactions may be the dominant route to H{sub 2} formation involving neutral polycyclic aromatic hydrocarbons (PAHs). The results indicate that highly superhydrogenated PAHs could well be formed and could act as efficient catalysts for H{sub 2} formation in the interstellar medium in low UV flux regions.

  7. 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%.

  8. 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%.

  9. 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.

  10. 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.

  11. 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.

  12. Synergistic kinetic inhibition of natural gas hydrate formation

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Malmos, Christine; von Solms, Nicolas

    2013-01-01

    Rocking cells were used to investigate the natural gas hydrate formation and decomposition in the presence of kinetic inhibitor, Luvicap. In addition, the influence of poly ethylene oxide (PEO) and NaCl on the performance of Luvicap was investigated using temperature ramping and isothermal...

  13. 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

  14. Characteristics of carbonate gas pool and multistage gas pool formation history of Hetianhe gas field, Tarim Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Hetianhe is a big carbonate gas field which is found and demonstrated in the period of "Chinese National Ninth 5-Year Plan". The proved reserve of Hetianhe gas field is over 600×108 m3. Its main producing layers are Carboniferous bioclastic limestone and Ordovician carbonate composed of buried hill. The former is stratified gas pool with water around its side, and the latter is massive gas pool with water in its bottom. The gases in the gas pools belong to dry gases with normal temperature and pressure systems. Based on the correlation of gas and source rock, the gases are mainly generated from Cambrian source rocks. According to the researches on source rock and structure evolution, and the observations on the thin section to reservoir bitumen and the studies on homogenization temperature of fluid inclusions, the gas pool has been identified and divided into three formation periods. The first is Late Caledonian when the oil generated from the Cambrian source rocks and migrated along faults, as a form of liquid facies into Ordovician carbonate reservoir and accumulated there. After that, the crust uplifted, the oil reservoir had been destroyed. The second is Late Hercynian when condensate gases generated from the Cambrian source rocks and migrated into Ordovician reservoir, as a form of liquid facies. Since the fractures had reached P strata, so the trap might have a real poor preservation condition, and the large-scale gas pool formation had not happened. The third gas reservoir formation period occurred in Himalaya. The fractures on both sides of Hetianhe gas field developed violently under the forces of compression, and thus the present fault horst formed. The dry gases generated from Cambrian source rocks and migrated upwards as the form of gas facies into Ordovician and Carboniferous reservoirs, and the large gas pool as discovered at present was formed finally.

  15. Evidence from SOFIA Imaging of Polycyclic Aromatic Hydrocarbon Formation along a Recent Outflow in NGC 7027

    CERN Document Server

    Lau, R M; Sahai, R; Ressler, M E

    2016-01-01

    We report spatially resolved (FWHM$\\sim3.8-4.6"$) mid-IR imaging observations of the planetary nebula (PN) NGC 7027 taken with the 2.5-m telescope aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). Images of NGC 7027 were acquired at 6.3, 6.6, 11.1, 19.7, 24.2, 33.6, and 37.1 $\\mu\\mathrm{m}$ using the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST).The observations reveal emission from Polycyclic Aromatic Hydrocarbon (PAH) and warm dust ($T_D\\sim90$ K) from the illuminated inner edge of the molecular envelope surrounding the ionized gas and central star. The DustEM code was used to fit the spectral energy distribution of fluxes obtained by FORCAST and the archival infrared spectrum of NGC 7027 acquired by the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). Best-fit dust models provide a total dust mass of $5.8^{+2.3}_{-2.6}\\times10^{-3}$ $\\mathrm{M}_\\odot$, where carbonaceous large ($a=1.5$ $\\mu$m) and very small ($a \\sim12\\AA$) grains, and PAHs ($...

  16. 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

  17. 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.).

  18. 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.

  19. Star formation and gas phase history of the cosmic web

    Science.gov (United States)

    Snedden, Ali; Coughlin, Jared; Phillips, Lara Arielle; Mathews, Grant; Suh, In-Saeng

    2016-01-01

    We present a new method of tracking and characterizing the environment in which galaxies and their associated circumgalactic medium evolve. We have developed a structure finding algorithm that uses the rate of change of the density gradient to self-consistently parse and follow the evolution of groups/clusters, filaments and voids in large-scale structure simulations. We use this to trace the complete evolution of the baryons in the gas phase and the star formation history within each structure in our simulated volume. We vary the structure measure threshold to probe the complex inner structure of star-forming regions in poor clusters, filaments and voids. We find that the majority of star formation occurs in cold, condensed gas in filaments at intermediate redshifts (z ˜ 3). We also show that much of the star formation above a redshift z = 3 occurs in low-contrast regions of filaments, but as the density contrast increases at lower redshift, star formation switches to the high-contrast regions, or inner parts, of filaments. Since filaments bridge the void and cluster regions, it suggests that the majority of star formation occurs in galaxies in intermediate density regions prior to the accretion on to groups/clusters. We find that both filaments and poor clusters are multiphase environments distinguishing themselves by different distributions of gas phases.

  20. 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.

  1. 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.

  2. Separation of SF6 from gas mixtures using gas hydrate formation.

    Science.gov (United States)

    Cha, Inuk; Lee, Seungmin; Lee, Ju Dong; Lee, Gang-woo; Seo, Yongwon

    2010-08-15

    This study aims to examine the thermodynamic feasibility of separating sulfur hexafluoride (SF(6)), which is widely used in various industrial fields and is one of the most potent greenhouse gases, from gas mixtures using gas hydrate formation. The key process variables of hydrate phase equilibria, pressure-composition diagram, formation kinetics, and structure identification of the mixed gas hydrates, were closely investigated to verify the overall concept of this hydrate-based SF(6) separation process. The three-phase equilibria of hydrate (H), liquid water (L(W)), and vapor (V) for the binary SF(6) + water mixture and for the ternary N(2) + SF(6) + water mixtures with various SF(6) vapor compositions (10, 30, 50, and 70%) were experimentally measured to determine the stability regions and formation conditions of pure and mixed hydrates. The pressure-composition diagram at two different temperatures of 276.15 and 281.15 K was obtained to investigate the actual SF(6) separation efficiency. The vapor phase composition change was monitored during gas hydrate formation to confirm the formation pattern and time needed to reach a state of equilibrium. Furthermore, the structure of the mixed N(2) + SF(6) hydrate was confirmed to be structure II via Raman spectroscopy. Through close examination of the overall experimental results, it was clearly verified that highly concentrated SF(6) can be separated from gas mixtures at mild temperatures and low pressure conditions.

  3. Direct hydrocarbons formation from CH{sub 4} and CO{sub 2} by non-thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Pham, M.H.; Tatibouet, J.M.; Batiot-Dupeyrat, C. [Univ. de Poitiers, Poitiers (France). Centre national de la recherche scientifique, Laboratoire de Catalyse en Chimie Organique

    2010-07-01

    Methane (CH{sub 4}) is typically burned to produce heat, the most degraded form of energy. This paper presented a possible way to conserve fossil carbon resources and limit carbon dioxide (CO{sub 2}) emissions by transforming methane into a chemical feedstock. The Fischer-Tropsch process is one of the possible ways of producing hydrocarbons by reforming CH{sub 4} by CO{sub 2} to obtain a mixture of carbon monoxide (CO) and hydrogen (H{sub 2}). However, previous studies have shown that hydrocarbons can by produced directly from a CH{sub 4} and CO{sub 2} mixture by non-thermal plasma, thereby avoiding the Fischer-Tropsch synthesis. This paper presented the results obtained in a coaxial dielectric discharge barrier (DBD) reactor for hydrocarbon formation by varying either the CH{sub 4}/CO{sub 2} ratio or the input energy. The main products were C{sub 2} to C{sub 4} alkanes. The increasing hydrocarbons to CO ratio with the CH{sub 4}/CO{sub 2} initial ratio suggests a radical type mechanism. It was concluded that a 15 percent hydrocarbon yield can be obtained in a single pass with only a short loss of initial carbon. 1 ref.

  4. 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

  5. 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

  6. 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

  7. Palynofacies characterization for hydrocarbon source rock evaluation in the Subathu Formation of Marhighat, Sirmaur district, Himachal Pradesh

    Indian Academy of Sciences (India)

    O P Thakur; N N Dogra

    2011-10-01

    This paper deals with the hydrocarbon source rock evaluation of the Subathu Formation exposed at Marhighat on Sarahan–Narag road in Sirmaur district of Himachal Pradesh. Hydrocarbon potential of these sediments is estimated on the basis of palynofacies analysis and thermal alteration index (TAI) values based on the fossil spores/pollen colouration. The analyses are based on the classification and hydrocarbon generation potential of plant derived dispersed organic matter present in the sediments. The palynofacies analysis of Subathu Formation in the area reveal moderate to rich organic matter, with amorphous organic matter constituting the bulk of the total organic matter, followed by charcoal, biodegraded organic matter, fungal remains, spores/pollen and structured terrestrial organic matter. The TAI value for the organic matter in these sediments has been ascertained as 3.00. A dominance of the sapropelic facies (amorphous organic matter) and the measured TAI values for the Subathu sediments in the Marhighat area suggests a good source-rock potential for the hydrocarbon generation.

  8. 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.

  9. 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.

  10. Polycyclic aromatic hydrocarbons (PAH) formation from the pyrolysis of different municipal solid waste fractions.

    Science.gov (United States)

    Zhou, Hui; Wu, Chunfei; Onwudili, Jude A; Meng, Aihong; Zhang, Yanguo; Williams, Paul T

    2015-02-01

    The formation of 2-4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock.

  11. Polycyclic aromatic hydrocarbons (PAH) formation from the pyrolysis of different municipal solid waste fractions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hui [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Wu, Chunfei, E-mail: c.wu@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Onwudili, Jude A. [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Meng, Aihong [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Yanguo, E-mail: zhangyg@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2015-02-15

    Highlights: • PAH from pyrolysis of 9 MSW fractions was investigated. • Pyrolysis of plastics released more PAH than that of biomass. • Naphthalene was the most abundant PAH in the tar. • The mechanism of PAH release from biomass and plastics was proposed. - Abstract: The formation of 2–4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock.

  12. Star formation in metal-poor gas clouds

    CERN Document Server

    Glover, Simon C O

    2012-01-01

    Observations of molecular clouds in metal-poor environments typically find that they have much higher star formation rates than one would expect based on their observed CO luminosities and the molecular gas masses that are inferred from them. This finding can be understood if one assumes that the conversion factor between CO luminosity and H2 mass is much larger in these low metallicity systems than in nearby molecular clouds. However, it is unclear whether this is the only factor at work, or whether the star formation rate of the clouds is directly sensitive to the metallicity of the gas. To investigate this, we have performed numerical simulations of the coupled dynamical, chemical and thermal evolution of model clouds with metallicities ranging from 0.01 Z_solar to Z_solar. We find that the star formation rate in our model clouds has little sensitivity to the metallicity. Reducing the metallicity of the gas by two orders of magnitude delays the onset of star formation in the clouds by no more than a cloud ...

  13. Rapid formation of molecular clouds from turbulent atomic gas

    Science.gov (United States)

    Glover, S. C. O.; Mac Low, M.-M.

    The characteristic lifetimes of molecular clouds remain uncertain and a topic of frequent debate, with arguments having recently been advanced both in support of short-lived clouds, with lifetimes of a few Myr or less (see e.g. Elmegreen 2000; Hartmann et al. 2001) and in support of much longer-lived clouds, with lifetimes of the order of 10 Myr or more (see e.g. Tassis & Mouschovias, 2004; Goldsmith & Li, 2005). An argument that has previously been advanced in favour of longer lived clouds is the apparent difficulty involved in converting sufficient atomic hydrogen to molecular hydrogen within the short timescale required by the rapid cloud formation scenario. However, previous estimates of the time required for this conversion to occur have not taken into account the effects of the supersonic turbulence which is inferred to be present in the atomic gas. In this contribution, we present results from a set of high resolution three-dimensional simulations of turbulence in gravitationally unstable atomic gas. These simulations were performed using a modified version of the ZEUS-MP hydrodynamical code (Norman 2000), and include a detailed treatment of the thermal balance of the gas and of the formation of molecular hydrogen. The effects of photodissociation of H2 by the Galactic UV field are also included, with a simple local approximation used to compute the effects of H2 self-shielding. The results of our simulations demonstrate that H2 formation occurs rapidly in turbulent atomic gas. Starting from purely atomic gas, large quantities of molecular gas can be produced on timescales of less than a Myr, given turbulent velocity dispersions and magnetic field strengths consistent with observations. Moreover, as our simulations underestimate the effectiveness of H2 self-shielding and dust absorption, we can be confident that the molecular fractions which we compute are strong lower limits on the true values. The formation of large quantities of molecular gas on the

  14. Molecular gas and star formation in the Milky Way

    Directory of Open Access Journals (Sweden)

    Combes F.

    2012-02-01

    Full Text Available The dense molecular gas is the ideal tracer of the spiral structure in the Milky Way, and should be used intensively to solve the puzzle of its structure. In spite of our position inside the plane, we can hope to disentangle the structures, with position-velocity diagrams, in addition to (l − b. I summarize the state of the art simulations of gas flows in the MW, and describe what can be done to improve the models, taking into account the star formation, in view of what is already done in external galaxies, with a more favorable viewing angle.

  15. Cold gas and star formation in a merging galaxy sequence

    Science.gov (United States)

    Georgakakis, Antonis; Forbes, Duncan A.; Norris, Ray P.

    2000-10-01

    We explore the evolution of the cold gas (molecular and neutral hydrogen) and star formation activity during galaxy interactions, using a merging galaxy sequence comprising both pre- and post-merger candidates. Data for this study come from the literature, but are supplemented by some new radio observations presented here. First, we confirm that the ratio of far-infrared luminosity to molecular hydrogen mass (LFIRM(H2); star formation efficiency) increases close to nuclear coalescence. After the merging of the two nuclei there is evidence that the star formation efficiency declines again to values typical of ellipticals. This trend can be attributed to M(H2) depletion arising from interaction induced star formation. However, there is significant scatter, likely to arise from differences in the interaction details (e.g., disc-to-bulge ratio, geometry) of individual systems. Secondly, we find that the central molecular hydrogen surface density, ΣH2, increases close to the final stages of the merging of the two nuclei. Such a trend, indicating gas inflows caused by gravitational instabilities during the interaction, is also predicted by numerical simulations. Furthermore, there is evidence for a decreasing fraction of cold gas mass from early interacting systems to merger remnants, attributed to neutral hydrogen conversion into other forms (e.g., stars, hot gas) and molecular hydrogen depletion resulting from ongoing star formation. The evolution of the total-radio to blue-band luminosity ratio, reflecting the total (disc and nucleus) star formation activity, is also investigated. Although this ratio is on average higher than that for isolated spirals, we find a marginal increase along the merging sequence, attributed to the relative insensitivity of disc star formation to interactions. However, a similar result is also obtained for the nuclear radio emission, although galaxy interactions are believed to significantly affect the activity (star formation, AGN) in the

  16. 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

  17. Interface formation between hydrocarbon ring molecules and III-V semiconductor surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Passmann, Regina

    2008-08-15

    In this work a systematical study to investigate the adsorption structures of small hydrocarbon ring shaped molecules on III-V semiconductor surfaces with Photo-Emission Spectroscopy (PES), Reflectance Anisotropy Spectroscopy (RAS), Scanning Tunneling Microscopy (STM) as well as Low Electron Energy Diffraction (LEED) was performed. To investigate the influence of the surface structure in detail the surface dimer configuration to the adsorption process of organic molecules GaAs(001) surfaces, the c(4 x 4), the (2 x 4) and the (4 x 2) have been investigated as well as the adsorption of cyclopentene on the InP(001)(2 x 4) reconstructed surface. In the direct comparison it is shown that cyclopentene bonds to the InP(001)(2 x 4) surface via a cycloaddition like reaction. During this adsorption the double bond splits which is in contrast to the adsorption of cyclopentene on the GaAs(001) surfaces. Therefrom it is concluded that the surface geometry has an influence on the resulting adsorption structure. In order to investigate the influence of the intra-molecular double bonds, cyclopentene (one double bond), 1,4-cyclohexadiene (two double bonds) and benzene (three double bonds) were used for the characterization of the interface formation. With the investigations on the GaAs(001) reconstructed surfaces it was shown that a dependency of the bonding configuration on the intra-molecular double bonds exists. During the adsorption of cyclopentene no evidence was found that the double bond has to be involved in the interface formation while during the adsorption of 1,4-cyclohexadiene and benzene the double bonds are involved. Furthermore it was found that a bonding to As atoms of the surface is more likely than a bonding to Ga atoms. (orig.)

  18. 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].

  19. Thermodynamic evolution of the cosmological baryonic gas II. Galaxy formation

    CERN Document Server

    Alimi, J M

    2004-01-01

    The problem of galaxy formation and its dependence on thermodynamic properties is addressed by using Eulerian hydrodynamic numerical simulations of large scale structure formation. Global galaxy properties are explored in simulations including gravitation, shock heating and cooling processes, and following self-consistently the chemical evolution of a primordial composition hydrogen-helium plasma without assuming collisional ionization equilibrium. The galaxy formation model is mainly based on the identification of converging dense cold gas regions. We show that the evolution at low redshift of the observed cosmic star formation rate density is reproduced, and that the galaxy-like object mass function is dominated by low-mass objects. The galaxy mass functions are well described by a two power-law Schechter function whose parameters are in good agreement with observational fits of the galaxy luminosity function. The high-mass end of the galaxy mass function includes objects formed at early epochs and residing...

  20. Kinetics of hydrate formation using gas bubble suspended in water

    Institute of Scientific and Technical Information of China (English)

    马昌峰; 陈光进; 郭天民

    2002-01-01

    An innovative experimental technique, which was devised to study the effects of temperature and pressure on the rate of hydrate formation at the surface of a gas bubble suspended in a stagnant water phase, was adapted in this work. Under such conditions, the hydrate-growth process is free from dynamic mass transfer factors. The rate of hydrate formation of methane and carbon dioxide has been systematically studied. The measured hydrate-growth data were correlated by using the molar Gibbs free energy as driving force. In the course of the experiments, some interesting surface phenomena were observed.

  1. Reduced kinetic mechanism of n-heptane oxidation in modeling polycyclic aromatic hydrocarbon formation in opposed-flow diffusion flames

    Institute of Scientific and Technical Information of China (English)

    Beijing ZHONG; Jun XI

    2008-01-01

    A reduced mechanism, which could couple with the multidimensional computational fluid dynamics code for quantitative description of a reacting flow, was developed for chemical kinetic modeling of polycyclic aro-matic hydrocarbon formation in an opposed-flow dif-fusion flame. The complete kinetic mechanism, which comprises 572 reactions and 108 species, was reduced to a simplified mechanism that includes only 83 reactions and 56 species through sensitivity analysis. The results computed via this reduced mechanism are nearly indistin-guishable from those via the detailed mechanism, which demonstrate that the model based on this reduced mech-anism can properly describe n-heptane oxidation chem-istry and quantitatively predict polycyclic aromatic hydrocarbon (such as benzene, naphthalene, phenan-threne and pyrene) formation in opposed-flow diffusion flames.

  2. Mud volcano venting induced gas hydrate formation at the upper slope accretionary wedge, offshore SW Taiwan

    Science.gov (United States)

    Lin, Saulwood; Tseng, Yi-Ting; Cheng, Wan-Yen; Chou, Cheng-Tien; Chen, NeiChen; Hsieh, I.-Chih

    2016-04-01

    TsanYao Mud Volcano (TYMV) is the largest mud volcano cone in the Hengchun Mud Volcano Group (HCMVG), located at the upper slope of the accrretionary wedge, southwest of Taiwan. The region is under active tectonic activity with the Philippine Plate, moving northwestward at a rate of ~8 cm/year. This region also receives huge quantity of suspended particle load of ~100 mT/year at present time from adjacent small rivers of the Island of Taiwan. Large loads of suspended sediments influx become a major source of organic carbon and later gas and other hydrocarbon. Gas and fluid in the mud volcano are actively venting from deep to the sea floor on the upper slope of the accretionary wedge. In order to understand venting on the HCMVG, echo sounder, towcam and coring were carried out. Pore water sulfate, chloride, potassium, calcium, stable isotope O-18, gas compositions, dissolved sulfide were analysed. The HCMVG consists of 12 volcano cones of different sizes. Large quantity of gas and fluid are venting directly from deep to the TYMV structure high, as well as 50+ other vents as appeared as flares on the echo sounder. Some flares are reaching to the atmosphere and likely a source of green house gases to the atmosphere. Venting fluids include gas bubbles, suspended particle, mud, and breccia. Breccia size could reach more than 12 cm in diameter. Circular bands in different color appeared around the cone may represent stages of vent eruptions. Compositions of vent gas include methane, ethane and propane. High proportions of ethane and propane in the vent gas demonstrated that source of gas are thermogenic in origin. Patchy authigenic carbonate, bacterial mats, bivalves, tube worms and other chemosynthesis organisms were supported by venting gas AOM process near the sea floor. Pore water chloride concentrations show distinct variation pattern from center cone to the side of the volcano, with low in the center and high away from the cone. Pore water with higher than seawater

  3. Abnormal formation pressures and oil-gas migration in China

    Institute of Scientific and Technical Information of China (English)

    华保钦

    1995-01-01

    Abnormal formation pressures occur not only in marine strata but also in terrestrialsedimentary basins in China.It develops most in Tertiary,followed by Mesozoic and Palaeozoic.Residualpressure decreases with the age of strata.Abnormal pressure raainly results from imbalanced compaction andhydrocarbon generation,and depends on various geological conditions.The secondary cause is the uplift ofcrust at the late stage and the transformation of clay minerals.Practical data show that the abnormal forma-tion pressure provides the dynamic force and passages for the primary migration of oil-gas,and in reservoirs,itcan affect the distribution of flow potential,which controls the migration direction and the aocumulation placeof oil and gas.

  4. Trajectory Dynamics of Gas Molecules and Galaxy Formation

    CERN Document Server

    Llanos, Pedro J; Hintz, Gerald R

    2013-01-01

    The probability distribution of the velocity of gas molecules in a closed container is described by the kinetic theory of gases. When molecules collide or impact the walls of a container, they exchange energy and momentum in accordance with Newton's laws of motion. Between collisions, the trajectory of individual molecules is a straight line, neglecting gravity. During the formation of a galaxy, the stars are constrained to a region of space and exchange energy and momentum in a manner similar to molecules. In this paper, an exact model of an ideal gas is derived and analyzed to determine the probability distribution of the molecular velocities, which are then compared with the probability distribution of velocities associated with stars during galaxy formation.

  5. Low nanopore connectivity limits gas production in Barnett formation

    Science.gov (United States)

    Hu, Qinhong; Ewing, Robert P.; Rowe, Harold D.

    2015-12-01

    Gas-producing wells in the Barnett Formation show a steep decline from initial production rates, even within the first year, and only 12-30% of the estimated gas in place is recovered. The underlying causes of these production constraints are not well understood. The rate-limiting step in gas production is likely diffusive transport from matrix storage to the stimulated fracture network. Transport through a porous material such as shale is controlled by both geometry (e.g., pore size distribution) and topology (e.g., pore connectivity). Through an integrated experimental and theoretical approach, this work finds that the Barnett Formation has sparsely connected pores. Evidence of low pore connectivity includes the sparse and heterogeneous presence of trace levels of diffusing solutes beyond a few millimeters from a sample edge, the anomalous behavior of spontaneous water imbibition, the steep decline in edge-accessible porosity observed in tracer concentrations following vacuum saturation, the low (about 0.2-0.4% by volume) level presence of Wood's metal alloy when injected at 600 MPa pressure, and high tortuosity from mercury injection capillary pressure. Results are consistent with an interpretation of pore connectivity based on percolation theory. Low pore connectivity of shale matrix limits its mass transfer interaction with the stimulated fracture network from hydraulic fracturing and serves as an important underlying cause for steep declines in gas production rates and a low overall recovery rate.

  6. Hydrate bearing clayey sediments: Formation and gas production concepts

    KAUST Repository

    Jang, Jaewon

    2016-06-20

    Hydro-thermo-chemo and mechanically coupled processes determine hydrate morphology and control gas production from hydrate-bearing sediments. Force balance, together with mass and energy conservation analyses anchored in published data provide robust asymptotic solutions that reflect governing processes in hydrate systems. Results demonstrate that hydrate segregation in clayey sediments results in a two-material system whereby hydrate lenses are surrounded by hydrate-free water-saturated clay. Hydrate saturation can reach ≈2% by concentrating the excess dissolved gas in the pore water and ≈20% from metabolizable carbon. Higher hydrate saturations are often found in natural sediments and imply methane transport by advection or diffusion processes. Hydrate dissociation is a strongly endothermic event; the available latent heat in a reservoir can sustain significant hydrate dissociation without triggering ice formation during depressurization. The volume of hydrate expands 2-to-4 times upon dissociation or CO2single bondCH4 replacement. Volume expansion can be controlled to maintain lenses open and to create new open mode discontinuities that favor gas recovery. Pore size is the most critical sediment parameter for hydrate formation and gas recovery and is controlled by the smallest grains in a sediment. Therefore any characterization must carefully consider the amount of fines and their associated mineralogy.

  7. Cold gas and star formation in a merging galaxy sequence

    CERN Document Server

    Georgakakis, A; Norris, R P; Georgakakis, Antonis; Forbes, Duncan A.; Norris, Ray P.

    2000-01-01

    We explore the evolution of the cold gas and star-formation activity during galaxy interactions, using a merging galaxy sequence comprising both pre- and post-mergers. Data for this study come from the literature but supplemented by new radio observations presented here. Firstly, we confirm that the star-formation efficiency (SFE) increases close to nuclear coalescence. At post-merger stages there is evidence that the SFE declines to values typical of ellipticals. This trend can be attributed to M(H_2) depletion due to interaction induced star-formation. However, there is significant scatter, likely to arise from differences in the interaction details of individual systems. Secondly, we find that the central molecular hydrogen surface density, increases close to the final stages of the merging of the two nuclei. Such a trend is also predicted by numerical simulations. Furthermore, there is evidence for a decreasing fraction of cold gas mass from early interacting systems to merger remnants, attributed to gas ...

  8. Geological and geochemical characterization of the Lower Cretaceous Pearsall Formation, Maverick Basin, south Texas: A future shale gas resource?

    Science.gov (United States)

    Hackley, Paul C.

    2012-01-01

    As part of an assessment of undiscovered hydrocarbon resources in the northern Gulf of Mexico onshore Mesozoic section, the U.S. Geological Survey (USGS) evaluated the Lower Cretaceous Pearsall Formation of the Maverick Basin, south Texas, as a potential shale gas resource. Wireline logs were used to determine the stratigraphic distribution of the Pearsall Formation and to select available core and cuttings samples for analytical investigation. Samples used for this study spanned updip to downdip environments in the Maverick Basin, including several from the current shale gas-producing area of the Pearsall Formation.The term shale does not adequately describe any of the Pearsall samples evaluated for this study, which included argillaceous lime wackestones from more proximal marine depositional environments in Maverick County and argillaceous lime mudstones from the distal Lower Cretaceous shelf edge in western Bee County. Most facies in the Pearsall Formation were deposited in oxygenated environments as evidenced by the presence of biota preserved as shell fragments and the near absence of sediment laminae, which is probably caused by bioturbation. Organic material is poorly preserved and primarily consists of type III kerogen (terrestrial) and type IV kerogen (inert solid bitumen), with a minor contribution from type II kerogen (marine) based on petrographic analysis and pyrolysis. Carbonate dominates the mineralogy followed by clays and quartz. The low abundance and broad size distribution of pyrite are consistent with the presence of oxic conditions during sediment deposition. The Pearsall Formation is in the dry gas window of hydrocarbon generation (mean random vitrinite reflectance values, Ro = 1.2–2.2%) and contains moderate levels of total organic carbon (average 0.86 wt. %), which primarily resides in the inert solid bitumen. Solid bitumen is interpreted to result from in-situ thermal cracking of liquid hydrocarbon generated from original type II kerogen

  9. 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.

  10. 四川盆地上三叠统须家河组煤系气源岩芳烃地球化学特征%Geochemical characteristics of aromatic hydrocarbons of coal-bearing gas source rocks from Upper Triassic Xujiahe Formation in Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    蔡杰; 张敏

    2013-01-01

      通过对四川盆地须家河组33个煤系气源岩芳烃馏分 GC-MS 分析与研究,揭示出研究区煤系气源岩芳烃的组成特征与典型的煤系源岩存在显著差异。主要表现为芳烃组成中表征高等植物生源输入的卡达烯、惹烯、1,2,5-三甲基萘、1,2,5,6-四甲基萘等化合物含量极低;而三芴系列相对百分含量表现出高硫芴与芴、低氧芴的特征,与典型煤系烃源岩中高氧芴含量之特征差异迥然。造成四川盆地须家河组煤系气源岩芳烃组成的特殊性原因可能与该地区曾经遭受过海侵作用和高热演化有关。%Thirty three coal-bearing gas source rock samples from the Upper Triassic Xujiahe Formation in the Si-chuan Basin were analyzed by GC-MS. The results show that the concentration of cadalene, retene, 1,2,5-tri-methylnaphthalene and 1,2,5,6-tetramethylnaphthalene derived from terrigenous higher plant organic matter of the coal-bearing gas source rocks are extremely lower than those of the typical coal-bearing source rocks. The relative contents of dibenzothiophenes and fluorenes are higher while the relative content of dibenzofurans is lower com-pared to the high content of dibenzofurans in typical coal-bearing source rocks. The particular distribution may be explained by transgression effect and high maturity.

  11. Formation of Massive Primordial Stars in a Reionized Gas

    CERN Document Server

    Yoshida, Naoki; Hernquist, Lars

    2007-01-01

    We use cosmological hydrodynamic simulations with unprecedented resolution to study the formation of primordial stars in an ionized gas at high redshifts. Our approach includes all the relevant atomic and molecular physics to follow the thermal evolution of a prestellar gas cloud to very high densities of ~10^{18} cm^{-3}. We locate a star-forming gas cloud within a reionized region in our cosmological simulation. The first run-away collapse is triggered when the gas cloud's mass is ~40 Msun. We show that the cloud core remains stable against chemo-thermal instability and also against gravitational deformation throughout its evolution. Consequently, a single proto-stellar seed is formed, which accretes the surrounding hot gas at the rate ~10^{-3} Msun/year. We carry out proto-stellar evolution calculations using the inferred accretion rate. The resulting mass of the star when it reaches the zero-age main sequence is M_ZAMS ~ 40 Msun. We argue that, since the obtained M_ZAMS is as large as the mass of the coll...

  12. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    Science.gov (United States)

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  13. 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.

  14. 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.

  15. Triggered star formation in giant HI supershells: ionized gas

    CERN Document Server

    Egorov, O V; Moiseev, A V

    2015-01-01

    We considered the regions of triggered star formation inside kpc-sized HI supershells in three dwarf galaxies: IC 1613, IC 2574 and Holmberg II. The ionized and neutral gas morphology and kinematics were studied based on our observations with scanning Fabry-Perot interferometer at the SAO RAS 6-m telescope and 21 cm archival data of THINGS and LITTLE THINGS surveys. The qualitative analysis of the observational data performed in order to highlight the two questions: why the star formation occurred very locally in the supershells, and how the ongoing star formation in HI supershells rims influence its evolution? During the investigation we discovered the phenomenon never observed before in galaxies IC 2574 and Holmberg II: we found faint giant (kpc-sized) ionized shells in H-alpha and [SII]6717,6731 lines inside the supergiant HI shells.

  16. 深部热流体对油气成藏的影响%Influences of Deeply Sourced Thermal Fluid on the Formation of Hydrocarbon Reservoirs

    Institute of Scientific and Technical Information of China (English)

    高波; 陶明信; 王万春

    2001-01-01

    Deeply sourced thermal fluid is a kind of supercritical fluidcomposed of several constituents. Rising upward, it can transmit energy and material, and regulate and redistribute them in the inner Earth. For the formation of oil and gas, hypogene hydrothermal fluid can increase the paleotemperature of depositional basin, accelerate the evolution history of source rocks and enlarge the volume of effective source rocks. It can also extract and enrich dispersive organic matter in sediments because of its higher dissolving and diffusing capacity, and obviously contribute hydrogen to hydrocarbon generation. So the deeply sourced thermal fluid provides part of material resources for hydrocarbon generation. In addition, the reaction between thermal fluid and surrounding rocks can improve their porosity and permeability. This is favorable for the migration and accumulation of hydrocarbons. Moreover, that the higher pressure and water content of thermal fluid can significantly retard the thermal destruction of hydrocarbon is advantageous to the preservation of oil and gas.%深部热流体是一种由多元组分构成的超临界流体,其上升活动可使地球内部的物质与能量发生调整或再分配。对油气而言,深部热流体携带的高热能可使沉积盆地的古地温升高,加快烃源岩的热演化进程,增加有效烃源岩的体积,促进烃类的生成;在上升过程中,因其具很强的溶解和扩散能力,故可萃取、富集沉积物中的分散有机质,同时又对生烃产生显著的加氢作用,从而为油气的形成补充物源。此外,热流体与围岩储层发生化学反应,可改善储层的孔渗条件,有利于油气的聚集成藏,而且因其具有较高的压力和含水量,可抑制烃类的热裂解而有利于油气的保存。

  17. Maximum Topological Distances Based Indices as Molecular Descriptors for QSPR. 4. Modeling the Enthalpy of Formation of Hydrocarbons from Elements

    Directory of Open Access Journals (Sweden)

    Andrey A. Toropov

    2001-06-01

    Full Text Available The enthalpy of formation of a set of 60 hydroarbons is calculated on the basis of topological descriptors defined from the distance and detour matrices within the realm of the QSAR/QSPR theory. Linear and non-linear polynomials fittings are made and results show the need to resort to higher-order regression equations in order to get better concordances between theoretical results and experimental available data. Besides, topological indices computed from maximum order distances seems to yield rather satisfactory predictions of heats of formation for hydrocarbons.

  18. Reservoir attributes of a hydrocarbon-prone sandstone complex: case of the Pab Formation (Late Cretaceous) of Southwest Pakistan

    DEFF Research Database (Denmark)

    Umar, Muhammad; Khan, Abdul Salam; Kelling, Gilbert;

    2016-01-01

    Links between the architectural elements of major sand bodies and reservoir attributes have been explored in a field study of the hydrocarbon-yielding Late Cretaceous Pab Formation of southwest Pakistan. The lithofacies and facies associations represented in the Pab Formation are the main...... porosity values than more shale-rich successions. Diagenetic studies of Pab sandstones reveal that intense mechanical compaction and cementation have reduced primary porosity and reservoir quality. Conversely, dissolution of detrital feldspar grains and volcanic fragments during burial and later uplift...

  19. New Insight into the Formation Mechanism of Imidazolium-Based Ionic Liquids from N-Alkyl Imidazoles and Halogenated Hydrocarbons: A Polar Microenvironment Induced and Autopromoted Process.

    Science.gov (United States)

    Mu, Xueli; Jiang, Nan; Liu, Chengbu; Zhang, Dongju

    2017-02-09

    To illustrate the formation mechanism of imidazolium-based ionic liquids (ILs) from N-alkyl imidazoles and halogenated hydrocarbons, density functional theory calculations have been carried out on a representative system, the reaction of N-methyl imidazole with chloroethane to form 1-ethyl-3-methyl imidazolium chloride ([Emim]Cl) IL. The reaction is shown to proceed via an SN2 transition state with a free energy barrier of 34.4 kcal/mol in the gas phase and 27.6 kcal/mol in toluene solvent. The reaction can be remarkably promoted by the presence of ionic products and water molecules. The calculated barriers in toluene are 22.0, 21.7, and 19.9 kcal/mol in the presence of 1-3 ionic pairs of [Emim]Cl and 23.5, 21.3, and 19.4 kcal/mol in the presence of 1-3 water molecules, respectively. These ionic pairs and water molecules do not participate directly in the reaction but provide a polar environment that favors stabilizing the transition state with large charge separation. Hence, we propose that the synthesis of imidazolium-based ILs from N-alkyl imidazoles and halogenated hydrocarbons is an autopromoted process and a polar microenvironment induced reaction, and the existence of water molecules (a highly polar solvent) in the reaction may be mainly responsible for the initiation of reaction.

  20. 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.

  1. Star formation in semi-analytic galaxy formation models with multiphase gas

    Science.gov (United States)

    Somerville, Rachel S.; Popping, Gergö; Trager, Scott C.

    2015-11-01

    We implement physically motivated recipes for partitioning cold gas into different phases (atomic, molecular, and ionized) in galaxies within semi-analytic models of galaxy formation based on cosmological merger trees. We then model the conversion of molecular gas into stars using empirical recipes motivated by recent observations. We explore the impact of these new recipes on the evolution of fundamental galaxy properties such as stellar mass, star formation rate (SFR), and gas and stellar phase metallicity. We present predictions for stellar mass functions, stellar mass versus SFR relations, and cold gas phase and stellar mass-metallicity relations for our fiducial models, from redshift z ˜ 6 to the present day. In addition we present predictions for the global SFR, mass assembly history, and cosmic enrichment history. We find that the predicted stellar properties of galaxies (stellar mass, SFR, metallicity) are remarkably insensitive to the details of the recipes used for partitioning gas into H I and H2. We see significant sensitivity to the recipes for H2 formation only in very low mass haloes (M_h ≲ 10^{10.5} M_{⊙}), which host galaxies with stellar masses m_* ≲ 10^8 M_{⊙}. The properties of low-mass galaxies are also quite insensitive to the details of the recipe used for converting H2 into stars, while the formation epoch of massive galaxies does depend on this significantly. We argue that this behaviour can be interpreted within the framework of a simple equilibrium model for galaxy evolution, in which the conversion of cold gas into stars is balanced on average by inflows and outflows.

  2. 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.

  3. 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.

  4. Gas, Stars, and Star Formation in Alfalfa Dwarf Galaxies

    Science.gov (United States)

    Huang, Shan; Haynes, Martha P.; Giovanelli, Riccardo; Brinchmann, Jarle; Stierwalt, Sabrina; Neff, Susan G.

    2012-01-01

    We examine the global properties of the stellar and Hi components of 229 low H i mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with H i masses ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs), and estimates of their SFRs and M* obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR distribution at M* approximately less than10(exp 8)M(sub 0) is driven by a set of dwarf galaxies that have low gas fractions and SSFRs; some of these are dE/dSphs in the Virgo Cluster. The imposition of an upper Hi mass limit yields the selection of a sample with lower gas fractions for their M* than found for the overall ALFALFA population. Many of the ALFALFA dwarfs, particularly the Virgo members, have H i depletion timescales shorter than a Hubble time. An examination of the dwarf galaxies within the full ALFALFA population in the context of global star formation (SF) laws is consistent with the general assumptions that gas-rich galaxies have lower SF efficiencies than do optically selected populations and that Hi disks are more extended than stellar ones.

  5. Mechanisms of abnormal overpressure generation in Kuqa foreland thrust belt and their impacts on oil and gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on overview for mechanism of abnormal overpressure generation in sedimentary basins, an insight discussion is made by the authors for the distribution, features and generation mechanisms of abnormal overpressure in the Kuqa foreland thrust belt. The abnormal overpressure in the Kelasu structure zone west to the Kuqa foreland thrust belt was primarily distributed in Eogene to lower Cretaceous formations; structural compression and structural emplacement as well as the containment of Eogene gyps-salt formation constituted the main mechanisms for the generation of abnormal overpressure. The abnormal overpressure zone in the eastern Yiqikelike structure zone was distributed primarily in lower Jurassic Ahe Group, resulting from hydrocarbon generation as well as structural stress other than from under-compaction. Various distributions and generating mechanisms have different impacts upon the formation of oil and gas reservoirs. K-E reservoir in the Kelasu zone is an allochthonous abnormal overpressure system. One of the conditions for reservoir accumulation is the migration of hydrocarbon (T-J hydrocarbon source rock) along the fault up to K-E reservoir and accumulated into reservoir. And this migration process was controlled by the abnormal overpressure system in K-E reservoir. The confined abnormal overpressure system in the Yiqikelike structure zone constituted the main cause for the poor developing of dissolved porosity in T-J reservoir, resulting in poor physical property of reservoir. The poor physical property of T-J reservoir of Yinan 2 structure was the main cause for the absence of oil accumulation, but the presence of natural gas reservoir in the structure.

  6. Surfactant process for promoting gas hydrate formation and application of the same

    Science.gov (United States)

    Rogers, Rudy E.; Zhong, Yu

    2002-01-01

    This invention relates to a method of storing gas using gas hydrates comprising forming gas hydrates in the presence of a water-surfactant solution that comprises water and surfactant. The addition of minor amounts of surfactant increases the gas hydrate formation rate, increases packing density of the solid hydrate mass and simplifies the formation-storage-decomposition process of gas hydrates. The minor amounts of surfactant also enhance the potential of gas hydrates for industrial storage applications.

  7. Molecular Gas and Star Formation in Nearby Disk Galaxies

    CERN Document Server

    Leroy, Adam K; Sandstrom, Karin; Schruba, Andreas; Munoz-Mateos, Juan-Carlos; Bigiel, Frank; Bolatto, Alberto; Brinks, Elias; de Blok, W J G; Meidt, Sharon; Rix, Hans-Walter; Rosolowsky, Erik; Schinnerer, Eva; Schuster, Karl-Friedrich; Usero, Antonio

    2013-01-01

    We compare molecular gas traced by 12CO(2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between Sig_mol and Sig_SFR but also find important second-order systematic variations in the apparent molecular gas depletion time, t_dep^mol = Sig_mol / Sig_SFR. At our 1 kpc common resolution, CO correlates closely with many tracers of the recent SFR. Weighting each line of sight equally and using a fixed, Milky Way alpha_CO, our data yield a molecular gas depletion time, t_dep^mol=Sig_mol/Sig_SFR ~ 2.2 Gyr with 0.3 dex scatter, in good agreement with literature data. We apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and the molecular gas surface density and find N=1+/-0.15 for our full data set with some variation from galaxy to galaxy. However, we caution that a power law treatment oversimplifies the topic given that we observe correlat...

  8. Characterization of kerogens from Ishikari-group coal-bearing formations by pyrolysis-gas chromatography/mass spectrometry; Ishikari sogun kyutanso kerojien no netsubunkai GC/MS ni yoru kyarakutarizeshon

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzuki, N.; Takano, O. [Japan National Oil Corp., Tokyo (Japan)

    1998-10-30

    In order to construct a model on expulsion of hydrocarbons from kerogen, it is necessary to have knowledge on composition of generated hydrocarbons. Characterization of the hydrocarbons from kerogens of Eocene Ishikari-group coal-bearing formations was carried out by pyrolysis-gas chromatography/mass spectrometry (Py-GCMS). Kerogen type classification by microscopic method was also carried out. Aliphatic hydrocarbons contents by Py-GCMS correlates to herbaceous kerogen contents by the microscopic method. Both of phenols content and aromatics content correlate to woody kerogen content. Therefore, coals and coaly shales deposited in transgression periods, which were recognized by depositional phase analysis, are richer in aliphatic-hydrocarbons content than those in regression period. This may be a reflection of environmental changes in paleoclimate and paleobotany. (author)

  9. 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

    proposed ,namely ,continuous accu-mulation (or basin-centered gas type or deep-basin gas type),quasi-continuous accumulation,and discontinuous (con-ventional trap type ) accumulation .Like the continuous accumulation ,the quasi-continuous accumulation also features in large area,without clear boundaries and water lags ,reservoir being adjacent to source rocks and pervasive distribution .In addition,non-buoyancy-driven hydrocarbon migration is dominant .The major driving forcers of migration are overpres-sure,diffusion and capillary pressure ,while buoyancy is limited .The migration is largely in the form of non-Darcy surge flow and diffusion flow .However , the quasi-continuous accumulation is different from the continuous accumulation in many aspects.The quasi-continuous accumulation commonly consists of many adjacent medium to small oil /gas reservoirs and the hydrocarbons are in quasi-continuous distribution .Oil/gas and water contact is complex and no regional updip water present .Hydrocarbon charging is mainly vertical and pervasive expulsion .Hydrocarbon accumulation is characte-rized by direct accumulation via primary migration or short-distance secondary migration .The reservoirs get tight prior to or contemporaneous with the hydrocarbon charging and are highly heterogeneous .The traps have certain controlling effect on hydrocarbon accumulation .The continuous unconventional accumulation represented by the basin-centred gas or deep-basin gas and the typical discontinuous conventional accumulation are representative of two end -member types of tight hy-drocarbon accumulations in complicated geological settings .Hence some transitional varieties must exist between them and the quasi-continuous accumulation is just such a transitional type that might be a universal and predominated pattern for large oil/gas accumulation to occur in tight formations .In reality,a typical continuous accumulation ought to be that occurs within a source rock interval like shale gas or

  10. 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)

  11. 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.

  12. 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.

  13. 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

  14. Cosmic walls and filaments formation in modified Chaplygin gas cosmology

    CERN Document Server

    Karbasi, S

    2016-01-01

    We want to study the perturbation growth of an initial seed of an ellipsoidal shape in Top-Hat collapse model of structure formation in the Modified Chaplygin gas cosmology. Considering reasonable values of the constants and the parameters of the model under study, it is shown that a very small deviation from spherical symmetry (ellipsoidal geometry) in the initial seed leads to a final highly non-spherical structure which can be considered as a candidate for justifying already known cosmological structures as cosmic walls and filaments.

  15. 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).

  16. 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.

  17. Study on the formation mechanism of shock wave in process of coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    SUN Dong-ling; MIAO Fa-tian; LIANG Yun-pei

    2009-01-01

    According to the research results of motion parameters of coal-gas flow, ana-lyzed the formation mechanism of shock waves at different states of coal-gas flow in the process of coal and gas outburst, and briefly described the two possible cases of outburst shock wave formation and their formation conditions in the process of coal and gas out-burst, and then pointed out that a high degree of under-expanded coal-gas flow was the main reason for the formation of a highly destructive shock wave. The research results improved the shock wave theory in coal and gas outburst.

  18. Planet formation signposts: observability of circumplanetary disks via gas kinematics

    CERN Document Server

    Perez, Sebastian; Casassus, Simon; Roman, Pablo; Szulágyi, Judit; Flores, Christian; Marino, Sebastian; Montesinos, Matias

    2015-01-01

    The identification of on-going planet formation requires the finest angular resolutions and deepest sensitivities in observations inspired by state-of-the-art numerical simulations. Hydrodynamic simulations of planet-disk interactions predict the formation of circumplanetary disks (CPDs) around accreting planetary cores. These CPDs have eluded unequivocal detection -their identification requires predictions in CPD tracers. In this work, we aim to assess the observability of embedded CPDs with ALMA as features imprinted in the gas kinematics. We use 3D Smooth Particle Hydrodynamic (SPH) simulations of CPDs around 1 and 5 M_Jup planets at large stellocentric radii, in locally isothermal and adiabatic disks. The simulations are then connected with 3D radiative transfer for predictions in CO isotopologues. Observability is assessed by corrupting with realistic long baseline phase noise extracted from the recent HL Tau ALMA data. We find that the presence of a CPD produces distinct signposts: 1) compact emission s...

  19. Effect of liquefied petroleum gas on ozone formation in Guadalajara and Mexico City.

    Science.gov (United States)

    Jaimes-López, J Luis; Sandoval-Fernández, Julio; González-Ortíz, Emmanuel; Vázquez-García, Marcos; González-Macías, Uriel; Zambrano-García, Angel

    2005-06-01

    Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O3) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O3 was monitored in each city for 20 days (8:00 a.m.-6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). Tested additions of both components were 35% (by volume) in GMA and 60% (by volume) in MCMA. The addition effects on O3 (max) were compared with effects from diluting LPG components or total nonmethane hydrocarbons (tNMHCs) by 50%. Diluting tNMHCs had the greatest absolute effect at both cities: it lowered O3 (max) by 24% in GMA and 55% in MCMA. Adding commercial LPG increased O3 (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O3 (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O3 (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O3 formation to a lesser extent than estimated previously.

  20. Lithofacies Architecturing and Hydrocarbon Reservoir Potential of Lumshiwal Formation: Surghar Range, Trans-Indus Ranges, North Pakistan

    Directory of Open Access Journals (Sweden)

    Iftikhar Alam

    2015-12-01

    directed Paleo-current system prevailed during deposition of Lumshiwal Formation. Diagenetic and tectonically induced fractures make the formation exceedingly porous and permeable as suitable reservoir horizon for the accumulation of hydrocarbon in the Trans-Indus ranges. The same formation has already been proven as potential reservoir horizon for hydrocarbon in the Kohat Plateau of northwest Pakistan. Secondly, the formation is dominantly comprised of silica/quartz sandstone (quartzarenite which can be used as silica sand, one of the essential raw materials for glass industries. The formation is also comprised of local coal seams which can be mined for production of coal in the region.

  1. 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

  2. Formation of organic solid phases in hydrocarbon reservoir fluids. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, S.I.; Lindeloff, N.; Stenby, E.H.

    1998-12-31

    The occurrence of solid phases during oil recovery is a potential problem. The present work has mainly been concerned with wax formation due to cooling of oils with a large paraffin content. 8 oils have been included in this project, although only a few of these have till now been subject to all the experimental techniques applied. The oils and wax fractions from these have been characterized using techniques such as GC-MS and Ftir. The goal has in part been to get a detailed description of the oil composition for use in model evaluation and development and in part to get a fundamental understanding of waxy oil properties and behaviour. A high pressure (200 bar) equipment has been developed for automatic detection of wax appearance using a filtration technique and laser light turbidimetry. The latter was found to be far superior to the filtration. The filtration was used to sample the incipient solid phase for characterization. However entrapment of liquid in the filters currently used have hampered this part. A number of model systems and one gas condensate have been investigated. The GC-MS procedure was found only to been able to detect molecules up to n-C45 and the group type analysis was not accurate enough for modelling purposes. Using Ftir it was obvious that incipient phases may contain very complex molecules (asphaltenes) which are not captured by GC-MS especially when fractionation is done using the acetone precipitation at elevated temperature. The latter fractionation procedure has been investigated thoroughly as a tool for understanding wax distribution etc. Within thermodynamic modelling a delta lattice parameter model has been developed which incorporates the non-ideality of the solid phases into the calculation of SLE. The non-ideality is estimated from pure component properties. A new algorithm for phase equilibria involving gas-liquid-solid has been developed. Currently both the model work and the experimental works are continued. (au)

  3. Polycyclic aromatic hydrocarbons and dust in regions of massive star formation

    NARCIS (Netherlands)

    Peeters, Els

    2002-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are known on earth as a large family of tarry materials naturally present in for example coal and crude oil. In addition, they are also formed in the combustion of all sorts of carbonaceous fuels and hence are found in auto exhaust, cigarette smoke, candle soo

  4. Polycyclic aromatic hydrocarbons and dust in regions of massive star formation

    NARCIS (Netherlands)

    Peeters, Els

    2002-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are known on earth as a large family of tarry materials naturally present in for example coal and crude oil. In addition, they are also formed in the combustion of all sorts of carbonaceous fuels and hence are found in auto exhaust, cigarette smoke, candle

  5. Scaling Relations between Gas and Star Formation in Nearby Galaxies

    CERN Document Server

    Bigiel, F; Walter, F

    2010-01-01

    High resolution, multi-wavelength maps of a sizeable set of nearby galaxies have made it possible to study how the surface densities of HI, H2 and star formation rate (Sigma_HI, Sigma_H2, Sigma_SFR) relate on scales of a few hundred parsecs. At these scales, individual galaxy disks are comfortably resolved, making it possible to assess gas-SFR relations with respect to environment within galaxies. Sigma_H2, traced by CO intensity, shows a strong correlation with Sigma_SFR and the ratio between these two quantities, the molecular gas depletion time, appears to be constant at about 2Gyr in large spiral galaxies. Within the star-forming disks of galaxies, Sigma_SFR shows almost no correlation with Sigma_HI. In the outer parts of galaxies, however, Sigma_SFR does scale with Sigma_HI, though with large scatter. Combining data from these different environments yields a distribution with multiple regimes in Sigma_gas - Sigma_SFR space. If the underlying assumptions to convert observables to physical quantities are m...

  6. Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 10, Basin analysis, formation and stability of gas hydrates of the Aleutian Trench and the Bering Sea

    Energy Technology Data Exchange (ETDEWEB)

    Krason, J.; Ciesnik, M.

    1987-01-01

    Four major areas with inferred gas hydrates are the subject of this study. Two of these areas, the Navarin and the Norton Basins, are located within the Bering Sea shelf, whereas the remaining areas of the Atka Basin in the central Aleutian Trench system and the eastern Aleutian Trench represent a huge region of the Aleutian Trench-Arc system. All four areas are geologically diverse and complex. Particularly the structural features of the accretionary wedge north of the Aleutian Trench still remain the subjects of scientific debates. Prior to this study, suggested presence of the gas hydrates in the four areas was based on seismic evidence, i.e., presence of bottom simulating reflectors (BSRs). Although the disclosure of the BSRs is often difficult, particularly under the structural conditions of the Navarin and Norton basins, it can be concluded that the identified BSRs are mostly represented by relatively weak and discontinuous reflectors. Under thermal and pressure conditions favorable for gas hydrate formation, the relative scarcity of the BSRs can be attributed to insufficient gas supply to the potential gas hydrate zone. Hydrocarbon gas in sediment may have biogenic, thermogenic or mixed origin. In the four studied areas, basin analysis revealed limited biogenic hydrocarbon generation. The migration of the thermogenically derived gases is probably diminished considerably due to the widespread diagenetic processes in diatomaceous strata. The latter processes resulted in the formation of the diagenetic horizons. The identified gas hydrate-related BSRs seem to be located in the areas of increased biogenic methanogenesis and faults acting as the pathways for thermogenic hydrocarbons.

  7. Characterization of shale gas enrichment in the Wufeng Formation–Longmaxi Formation in the Sichuan Basin of China and evaluation of its geological construction–transformation evolution sequence

    Directory of Open Access Journals (Sweden)

    Zhiliang He

    2017-02-01

    Full Text Available Shale gas in Upper Ordovician Wufeng Formation–Lower Silurian Longmaxi Formation in the Sichuan Basin is one of the key strata being explored and developed in China, where shale gas reservoirs have been found in Fuling, Weiyuan, Changning and Zhaotong. Characteristics of shale gas enrichment in the formation shown by detailed profiling and analysis are summarized as “high, handsome and rich”. “High” mainly refers to the high quality of original materials for the formation of shale with excellent key parameters, including the good type and high abundance of organic matters, high content of brittle minerals and moderate thermal evolution. “Handsome” means late and weak deformation, favorable deformation mode and structure, and appropriate uplift and current burial depth. “Rich” includes high gas content, high formation pressure coefficient, good reservoir property, favorable reservoir scale transformation and high initial and final output, with relative ease of development and obvious economic benefit. For shale gas enrichment and high yield, it is important that the combination of shale was deposited and formed in excellent conditions (geological construction, and then underwent appropriate tectonic deformation, uplift, and erosion (geological transformation. Evaluation based on geological construction (evolution sequence from formation to the reservoir includes sequence stratigraphy and sediment, hydrocarbon generation and formation of reservoir pores. Based on geological transformation (evolution sequence from the reservoir to preservation, the strata should be evaluated for structural deformation, the formation of reservoir fracture and preservation of shale gas. The evaluation of the “construction - transformation” sequence is to cover the whole process of shale gas formation and preservation. This way, both positive and negative effects of the formation-transformation sequence on shale gas are assessed. The evaluation

  8. Hydrocarbons in the Hauptsalz formation of the Gorleben salt dome. Content, distribution and origin

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Maximilian; Hammer, Joerg; Ostertag-Henning, Christian [Federal Institute for Geosciences and Natural Resources (BGR), Hannover (Germany)

    2015-07-01

    In the frame of the geological exploration of the Gorleben salt dome (November 2010 to November 2012) concentrations and compositions of hydrocarbons occuring in the main rock salt (Hauptsalz, Stassfurt series, z2) have been investigated. These exploration works followed former investigations of Gerling et al. (2002) and Bornemann et al. (2008). In order to get fresh, unaltered and representative samples beyond the EDZ (excavation damaged zone) for mineralogical and geochemical analyses, about 45 boreholes have been drilled at the 840 m level of the Gorleben exploration mine. These boreholes have been arranged in equal distances (depending on the mine structure) alongside crosscut 1 west (each 6 m long) and crosscut 1 east (each 9 m long). In addition 20 packer boreholes (10 packer boreholes per crosscut) for pressure build-up recording and hydrocarbon sampling have also been established. Immediately after drilling, core samples from the Hauptsalz for organic geochemical analyses have been retrieved and were dissolved in deionised and degased water. The results of analyses of about 210 samples scattered over all 45 boreholes reveal a total background concentration of hydrocarbons (C{sub 1} to C{sub 40}) of 0,24 mg/kg. 70 samples have concentrations between 1 mg/kg and 50 mg/kg (average 2,66 mg/kg) with 5 outliers up to 442 mg/kg in crosscut 1 west (Hammer et al. 2012, 2013). The drill cores have been investigated and documented by using ultraviolet light (l = 254 nm) in respect of visible indications of the existence of fluorescing aromatic hydrocarbons. Analyses revealed a high level of heterogeneous hydrocarbon distribution in the shape of isolated, irregular streaks, clusters, clouds and occasionally layers mainly located in recrystallized zones of the Hauptsalz. Thin sections and thick sections showed that hydrocarbons in z2HS1 (Knaeuelsalz) and z2HS2 (Streifensalz) samples are either located as black to brownish dendritical fluid inclusions alongside the grain

  9. 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...

  10. 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.

  11. 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.

  12. Hydrocarbon potential of Early Cretaceous lacustrine sediments from Bima Formation, Yola Sub-basin, Northern Benue Trough, NE Nigeria: Insight from organic geochemistry and petrology

    Science.gov (United States)

    Sarki Yandoka, Babangida M.; Abdullah, Wan Hasiah; Abubakar, M. B.; Adegoke, Adebanji Kayode; Maigari, A. S.; Haruna, A. I.; Yaro, Usman Y.

    2017-05-01

    The Early Cretaceous lacustrine sediments from Bima Formation in the Yola Sub-basin, Northern Benue Trough, northeastern Nigeria were studied based on organic geochemistry and petrology. This is in other to provide information on hydrocarbon generation potential; organic matter type (quality), richness (quantity), origin/source inputs, redox conditions (preservation) and thermal maturation in relation to thermal effect of Tertiary volcanics. The total organic carbon (TOC) contents ranges from 0.38 to 0.86 wt % with extractable organic matter (EOM) below 1000 ppm and pyrolysis S2 yield values from 0.16 to 0.68 mg/g, suggesting poor to fair source rock richness. Based on kerogen pyrolysis and microscopy coupled with biomarker parameters, the organic matters contain Type I (lacustrine algae), Type III (terrestrially derived land-plants) and Type IV kerogens deposited in a mixed lacustrine-terrestrial environment under suboxic to relatively anoxic conditions. This suggest potential occurrence of Early Cretaceous lacustrine sediments (perhaps Lower Cretaceous petroleum system) in Yola Sub-basin of the Northern Benue Trough as present in the neighbouring basins of Chad, Niger and Sudan Republics that have both oil and gas generation potential within the same rift trend (WCARS). Vitrinite reflectance (%Ro) and Tmax values of the lacustrine shales ranges from 1.12 to 2.32 VRo% and 448-501 °C, respectively, indicating peak-late to post-maturity stage. This is supported by the presence of dark brown palynomorphs, amorphous organic matter and phytoclasts as well as inertinite macerals. Consequently, the organic matters in the lacustrine shales of Bima Formation in the Yola Sub-basin appeared as a source of oil (most likely even waxy) and gas prone at a relatively deeper part of the basin. However, the high thermal maturity enhanced the organic matters and most of the hydrocarbons that formed in the course of thermal maturation were likely expelled to the reservoir rock units

  13. 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.

  14. A study on the geochemical characteristics of natural gas and gas sources in the Bozhong sag

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Natural gas is composed largely of hydrocarbon gas, especially wet gas in the Bozhong sag. The carbon isotopic composition shows that the gas is of organic origin. The carbon isotopic values of ethane indicate that the natural gas is dominated by mixed gas with minor coal-generated gas and oil-type gas. A gas-source correlation study showed that the source rocks of natural gas are those of the Lower Dongying Formation, the Shahejie Formation and the pre-Tertiary. The natural gas is characterized by multi-source and continuous generation in the study area, indicating that gas exploration potential is good in the Bozhong sag.

  15. Formation of unsaturated hydrocarbons in interstellar ice analogs by cosmic rays

    CERN Document Server

    Pilling, S; da Silveira, E F; Rothard, H; Domaracka, A; Boduch, P

    2012-01-01

    The formation of double and triple C-C bonds from the processing of pure c-C6H12 (cyclohexane) and mixed H2O:NH3:c-C6H12 (1:0.3:0.7) ices by highly-charged, and energetic ions (219 MeV O^{7+} and 632 MeV Ni^{24+}) is studied. The experiments simulate the physical chemistry induced by medium-mass and heavy-ion cosmic rays in interstellar ices analogs. The measurements were performed inside a high vacuum chamber at the heavy-ion accelerator GANIL (Grand Accel\\'erat\\'eur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a polished CsI substrate previously cooled to 13 K. In-situ analysis was performed by a Fourier transform infrared (FTIR) spectrometry at different ion fluences. Dissociation cross section of cyclohexane and its half-life in astrophysical environments were determined. A comparison between spectra of bombarded ices and young stellar sources indicates that the initial composition of grains in theses environments should contain a mixture of H2O, NH3, CO (or CO2), simple al...

  16. GAS PHASE SYNTHESIS OF (ISO)QUINOLINE AND ITS ROLE IN THE FORMATION OF NUCLEOBASES IN THE INTERSTELLAR MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Dorian S. N.; Kaiser, Ralf I. [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Kostko, Oleg; Troy, Tyler P.; Ahmed, Musahid [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Mebel, Alexander M. [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Tielens, Alexander G. G. M. [Leiden Observatory, University of Leiden, Leiden (Netherlands)

    2015-04-20

    Nitrogen-substituted polycyclic aromatic hydrocarbons (NPAHs) have been proposed to play a key role in the astrochemical evolution of the interstellar medium, yet the formation mechanisms of even their simplest prototypes—quinoline and isoquinoline—remain elusive. Here, we reveal a novel concept that under high temperature conditions representing circumstellar envelopes of carbon stars, (iso)quinoline can be synthesized via the reaction of pyridyl radicals with two acetylene molecules. The facile gas phase formation of (iso)quinoline in circumstellar envelopes defines a hitherto elusive reaction class synthesizing aromatic structures with embedded nitrogen atoms that are essential building blocks in contemporary biological-structural motifs. Once ejected from circumstellar shells and incorporated into icy interstellar grains in cold molecular clouds, these NPAHs can be functionalized by photo processing forming nucleobase-type structures as sampled in the Murchison meteorite.

  17. Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways

    Directory of Open Access Journals (Sweden)

    D. K. Henze

    2007-10-01

    Full Text Available Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO or hydroperoxy radical (HO2 to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those

  18. Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs. low-yield pathways

    Directory of Open Access Journals (Sweden)

    D. K. Henze

    2008-05-01

    Full Text Available Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitric oxide (NO or hydroperoxy radical (HO2 to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to global formation of SOA, with a total production nearly equal that of toluene and xylene combined. Global production of SOA from aromatic sources via the mechanisms identified here is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Uncertainty in these estimates owing to factors ranging from the atmospheric relevance of chamber conditions to model deficiencies result in an estimated range of SOA production from aromatics of 2–12 Tg/yr. Though this uncertainty range affords a significant anthropogenic contribution to global SOA, it is evident from comparisons to recent observations that additional pathways for

  19. Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reservoir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

  20. SHIELD: Comparing Gas and Star Formation in Low Mass Galaxies

    CERN Document Server

    Teich, Yaron G; Nims, Elise; Cannon, John M; Adams, Elizabeth A K; Bernstein-Cooper, Elijah Z; Giovanelli, Riccardo; Haynes, Martha P; Józsa, Gyula I G; McQuinn, Kristen B W; Salzer, John J; Skillman, Evan D; Warren, Steven R; Dolphin, Andrew; Elson, E C; Haurberg, Nathalie; Ott, Jürgen; Saintonge, Amelie; Cave, Ian; Hagen, Cedric; Huang, Shan; Janowiecki, Steven; Marshall, Melissa V; Thomann, Clara M; Van Sistine, Angela

    2016-01-01

    We analyze the relationships between atomic, neutral hydrogen (HI) and star formation (SF) in the 12 low-mass SHIELD galaxies. We compare high spectral (~0.82 km/s/channel) and spatial resolution (physical resolutions of 170 pc - 700 pc) HI imaging from the VLA with H\\alpha and far-ultraviolet imaging. We quantify the degree of co-spatiality between star forming regions and regions of high HI column densities. We calculate the global star formation efficiencies (SFE, $\\Sigma_{\\rm SFR}$ / $\\Sigma_{\\rm HI}$), and examine the relationships among the SFE and HI mass, HI column density, and star formation rate (SFR). The systems are consuming their cold neutral gas on timescales of order a few Gyr. While we derive an index for the Kennicutt-Schmidt relation of N ~ 0.68 $\\pm$ 0.04 for the SHIELD sample as a whole, the values of N vary considerably from system to system. By supplementing SHIELD results with those from other surveys, we find that HI mass and UV-based SFR are strongly correlated over five orders of ma...

  1. 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.

  2. MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, Adam K.; Munoz-Mateos, Juan-Carlos [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Walter, Fabian; Sandstrom, Karin; Meidt, Sharon; Rix, Hans-Walter; Schinnerer, Eva [Max Planck Institute fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Schruba, Andreas [California Institute for Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bigiel, Frank [Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Bolatto, Alberto [Department of Astronomy, University of Maryland, College Park, MD (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); De Blok, W. J. G. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Rosolowsky, Erik [University of British Columbia, Okanagan Campus, Kelowna, BC (Canada); Schuster, Karl-Friedrich [IRAM, 300 rue de la Piscine, F-38406 St. Martin d' Heres (France); Usero, Antonio [Observatorio Astronomico Nacional, C/ Alfonso XII, 3, E-28014 Madrid (Spain)

    2013-08-01

    We compare molecular gas traced by {sup 12}CO (2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between {Sigma}{sub mol} and {Sigma}{sub SFR} but also find important second-order systematic variations in the apparent molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}. At the 1 kpc common resolution of HERACLES, CO emission correlates closely with many tracers of the recent SFR. Weighting each line of sight equally, using a fixed {alpha}{sub CO} equivalent to the Milky Way value, our data yield a molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}{approx}2.2 Gyr with 0.3 dex 1{sigma} scatter, in very good agreement with recent literature data. We apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and the molecular gas surface density, {Sigma}{sub SFR}{proportional_to}{Sigma}{sub mol}{sup N}. We find N = 1 {+-} 0.15 for our full data set with some scatter from galaxy to galaxy. This also agrees with recent work, but we caution that a power-law treatment oversimplifies the topic given that we observe correlations between {tau}{sub dep}{sup mol} and other local and global quantities. The strongest of these are a decreased {tau}{sub dep}{sup mol} in low-mass, low-metallicity galaxies and a correlation of the kpc-scale {tau}{sub dep}{sup mol} with dust-to-gas ratio, D/G. These correlations can be explained by a CO-to-H{sub 2} conversion factor ({alpha}{sub CO}) that depends on dust shielding, and thus D/G, in the theoretically expected way. This is not a unique interpretation, but external evidence of conversion factor variations makes this the most conservative explanation of the strongest observed {tau}{sub dep}{sup mol} trends. After applying a D/G-dependent {alpha}{sub CO}, some weak correlations between {tau}{sub dep

  3. Ab initio heats of formation for chlorinated hydrocarbons: Allyl chloride, cis- and trans-1-chloropropene, and vinyl chloride

    Science.gov (United States)

    Colegrove, Brenda Thies; Thompson, Tyler B.

    1997-01-01

    Ab initio molecular energies at several levels of theory (MP4/6-311G**//MP2/6-31G*, MP4/6-311+G**//MP2/6-31G*,G1, and G2) are used to determine the heats of formation of several chlorinated hydrocarbons (allyl chloride, cis- and trans-1-chloropropene, and vinyl chloride) from atomization and isodesmic reactions. More than one isodesmic reaction was investigated for each molecule. Inconsistencies between the results from isodesmic reactions for a given molecule indicated possible errors in the experimental heats of formation for some of the chlorinated molecules used as references in the isodesmic reactions (in particular 1-chloropropane and 2-chloropropane). To further examine this possibility we did a multivariate regression for the G2 calculated reaction enthalpies for the 30 isodesmic reactions. In the regression, the heats of formation of the hydrocarbons and CH3Cl were fixed at the experimental values. The heats of formation of all the other chlorinated hydrocarbons were varied. The heats of formation determined using this method were: ΔHf298(CH2Cl2)=-22.6 kcal/mole, ΔHf298(CHCl=Cl2)=5.0 kcal/mole, ΔHf298(CCl2=CH2)=-0.2 kcal/mole, ΔHf298(CH2Cl-CH3)=-27.0 kcal/mole, ΔHf298(c-CHCl=CH-CH3)=-3.1 kcal/mole, ΔHf298(t-CHCl=CH-CH3)=-2.8 kcal/mole, ΔHf298(CH2=CClCH3)=-5.4 kcal/mole, ΔHf298(CH2=CH-CH2Cl)=-0.8 kcal/mole, ΔHf298(CH2Cl-CH2-CH3) =-32.2 kcal/mole, ΔHf298(CH3-CHCl-CH3 )=-35.9 kcal/mole. The calculated heats of formation were used to derive the following Benson group enthalpy values: C-(Cl)(H)2(Cd)=-15.6 kcal/mole, Cd-(Cl)(H)=-1.3 kcal/mole, and cis-halogen-alkyl =-0.3 kcal/mole.

  4. Combustion Chamber Deposits and PAH Formation in SI Engines Fueled by Producer Gas from Biomass Gasification

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Schramm, Jesper

    2003-01-01

    Investigations were made concerning the formation of combustion chamber deposits (CCD) in SI gas engines fueled by producer gas. The main objective was to determine and characterise CCD and PAH formation caused by the presence of the light tar compounds phenol and guaiacol in producer gas from an...

  5. Influences of different types of magnetic fields on HCFC-141b gas hydrate formation processes

    Institute of Scientific and Technical Information of China (English)

    SHU; Bifen; MA; Xiaolin; GUO; Kaihua; LI; Jianhong

    2004-01-01

    In this study, visualizations and experiments are carried out on the influence of static and rotating magnetic fields on the characteristics of HCFC-141b gas hydrate formation, such as crystallization form, formation temperature and induction time. It has been found that a proper rotating magnetic field can considerably improve the low-pressure gas hydrate formation process,especially in increasing the formation temperature and shortening the induction time. The morphology of the gas hydrate formation appears rather complex and compact. However, a proper static magnetic field can make the gas hydrate crystal more organized, which will be benefit to heat transfer.

  6. 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).

  7. 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.

  8. 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)

  9. SMBH Formation via Gas Accretion in Nuclear Stellar Clusters

    CERN Document Server

    Davies, Melvyn B; Bellovary, Jillian M

    2011-01-01

    Black holes exceeding a billion solar masses have been detected at redshifts greater than six. The rapid formation of these objects may suggest a massive early seed or a period of growth faster than Eddington. Here we suggest a new mechanism along these lines. We propose that in the process of hierarchical structure assembly, dense star clusters can be contracted on dynamical time scales due to the nearly free-fall inflow of self-gravitating gas with a mass comparable to or larger than that of the clusters. This increases the velocity dispersion to the point that the few remaining hard binaries can no longer effectively heat the cluster, and the cluster goes into a period of homologous core collapse. The cluster core can then reach a central density high enough for fast mergers of stellar-mass black holes and hence the rapid production of a black hole seed that could be $10^5 M_\\odot$ or larger.

  10. Primary emissions and secondary formation of volatile organic compounds from natural gas production in five major U.S. shale plays

    Science.gov (United States)

    Gilman, J.; Lerner, B. M.; Warneke, C.; Graus, M.; Lui, R.; Koss, A.; Yuan, B.; Murphy, S. M.; Alvarez, S. L.; Lefer, B. L.; Min, K. E.; Brown, S. S.; Roberts, J. M.; Osthoff, H. D.; Hatch, C. D.; Peischl, J.; Ryerson, T. B.; De Gouw, J. A.

    2014-12-01

    According to the U.S. Energy and Information Administration (EIA), domestic production of natural gas from shale formations is currently at the highest levels in U.S. history. Shale gas production may also result in the production of natural gas plant liquids (NGPLs) such as ethane and propane as well as natural gas condensate composed of a complex mixture of non-methane hydrocarbons containing more than ~5 carbon atoms (e.g., hexane, cyclohexane, and benzene). The amounts of natural gas liquids and condensate produced depends on the particular reservoir. The source signature of primary emissions of hydrocarbons to the atmosphere within each shale play will therefore depend on the composition of the raw natural gas as well as the industrial processes and equipment used to extract, separate, store, and transport the raw materials. Characterizing the primary emissions of VOCs from natural gas production is critical to assessing the local and regional atmospheric impacts such as the photochemical formation of ozone and secondary formation of organic aerosol. This study utilizes ground-based measurements of a full suite of volatile organic compounds (VOCs) in two western U.S. basins, the Uintah (2012-2014 winter measurements only) and Denver-Julesburg (winter 2011 and summer 2012), and airborne measurements over the Haynesville, Fayetteville, and Marcellus shale basins (summer 2013). By comparing the observed VOC to propane enhancement ratios, we show that each basin has a unique VOC source signature associated with oil and natural gas operations. Of the shale basins studied, the Uintah basin had the largest overall VOC to propane enhancement ratios while the Marcellus had the lowest. For the western basins, we will compare the composition of oxygenated VOCs produced from photochemical oxidation of VOC precursors and contrast the oxygenated VOC mixture to a "typical" summertime urban VOC mixture. The relative roles of alkanes, alkenes, aromatics, and cycloalkanes as

  11. Hydrocarbon sources and stages of reservoir formation in Kuqa depression, Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Kuqa depression bears not only plenty of natural gas, but also a large amount of condensate and smallquantity of crude oil. Based on the geochemical correlationbetween the Jurassic and Triassic terrestrial hydrocarbonsource rock, this paper confirms that the natural gas in Kuqadepression belongs to coal-type gas and the main gas sourcerock is attributed to the middle to lower Jurassic coal seriesformation, while the main oil source rock is the upper Tri-assic lacustrine mudstone. The authors indicated that Kuqadepression was slowly subsided in Mesozoic, but rapidlywent down in Late Tertiary, which made the Jurassic and Triassic source rock suddenly deep-buried and rapidlyevolved to high and over-mature phase since 5 Ma. The Triassic source rock is postponed to the Early Miocene dur-ing 23-12 Ma when entering the oil-generating peak, whilethe Jurassic is suspended to the latest 5 Ma, especially since2.5 Ma to the dry gas-generating period, which is one of thecharacteristics of the source rock thermal evolution in Kuqadepression. This paper presents a two-stage trapping andlate gas trapping model in Kuqa depression whose charac-teristics are: The main oil and gas reservoirs have differentsources. The oil reservoir is formed early while the gas reservoir is formed lately. During the early stage, it, mainly as oil, takes long distance lateral migration, while in the later stage, it, mainly as gas, takes the vertical migration and also has lateral migration. The trap formed in different time on the south and north sides of the depression and evolved into a distributional pattern with oil in the south part and gas in the north, also oil on the outer ring and gas on the inner ring. This paper points out that the late trapping of the natural gas in Kuqa depression is favorable for the preservation of large gas fields.

  12. Evolution of Gas Giant Entropy During Formation by Runaway Accretion

    CERN Document Server

    Berardo, David; Marleau, Gabriel-Dominique

    2016-01-01

    We calculate the evolution of gas giant planets during the runaway gas accretion phase of formation, to understand how the luminosity of young giant planets depends on the accretion conditions. We construct steady-state envelope models, and run time-dependent simulations of accreting planets with the Modules for Experiments in Stellar Astrophysics (MESA) code. We show that the evolution of the internal entropy depends on the contrast between the internal adiabat and the entropy of the accreted material, parametrized by the shock temperature $T_0$ and pressure $P_0$. At low temperatures ($T_0\\lesssim 300$--$1000\\ {\\rm K}$, depending on model parameters), the accreted material has a lower entropy than the interior. The convection zone extends to the surface and can drive a large luminosity, leading to rapid cooling and cold starts. For higher temperatures, the accreted material has a larger entropy than the interior, giving a radiative zone that stalls cooling. For $T_0\\gtrsim 2000\\ {\\rm K}$, the surface--inter...

  13. Photoirradiation of representative polycyclic aromatic hydrocarbons and twelve isomeric methylbenz[a]anthracene with UVA light: formation of lipid peroxidation.

    Science.gov (United States)

    Xia, Qingsu; Chou, Ming W; Yin, Jun J; Howard, Paul C; Yu, Hongtao; Fu, Peter P

    2006-05-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread genotoxic environmental pollutants, which require metabolic activation in order to exert biological activities, including mutagenicity and carcinogenicity. Photoactivation is another activation pathway that can lead to PAH genotoxicity. In this paper, we demonstrate that photoirradiation of a series of representative PAHs, with and without bearing a methyl substituent, with UVA light in the presence of methyl linoleate resulted in the formation of methyl linoleate hydroperoxides (a lipid peroxide). The lipid peroxide formation was inhibited by dithiothreitol (DTT) (free radical scavenger), NaN3 (singlet oxygen and free radical scavenger), and superoxide dismutase (SOD) (superoxide scavenger), but was enhanced by the presence of deuterium oxide (D2O) (extends singlet oxygen lifetime). These results suggest that photoirradiation of PAHs by UVA light generates reactive oxygen species (ROS), which induce lipid peroxidation.

  14. 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.

  15. EXPERIMENTAL INVESTIGATION ON GAS HYDRATE FORMATION IN PRESENCE OF ADDITIVE COMPONENTS

    Institute of Scientific and Technical Information of China (English)

    SUN Zhigao; FAN Shuanshi; GUO Kaihua

    2003-01-01

    Additives were used to increase gas hydrate formation rate and storage capacity. Experimental tests of methane hydrate formation were carried out in surfactant water solutions in a high-pressure cell.Sodium dodecyl sulfate (SDS) and alkyl polysaccharide glycoside (APG) were used to increase hydrate formation. The effect of SDS on hydrate formation is more pronounced compared APG. Cyclopentane (CP) also improves hydrate formation rates while it cannot increase methane gas storage capacity.

  16. 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).

  17. 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

  18. 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

  19. Where does the gas fueling star formation in BCGs originate?

    CERN Document Server

    Molendi, S; Gaspari, M; De Grandi, S; Gastaldello, F; Ghizzardi, S; Rossetti, M C

    2016-01-01

    We investigate the relationship between X-ray cooling and star formation in brightest cluster galaxies (BCGs). We present an X-ray spectral analysis of the inner regions, 10-40 kpc, of six nearby cool core clusters (z<0.35) observed with Chandra ACIS. This sample is selected on the basis of the high star formation rate (SFR) observed in the BCGs. We restrict our search for cooling gas to regions that are roughly cospatial with the starburst. We fit single- and multi-temperature mkcflow models to constrain the amount of isobarically cooling intracluster medium (ICM). We find that in all clusters, below a threshold temperature ranging between 0.9 and 3 keV, only upper limits can be obtained. In four out of six objects, the upper limits are significantly below the SFR and in two, namely A1835 and A1068, they are less than a tenth of the SFR. Our results suggests that a number of mechanisms conspire to hide the cooling signature in our spectra. In a few systems the lack of a cooling signature may be attributed...

  20. Gas, Stars and Star Formation in ALFALFA Dwarf Galaxies

    CERN Document Server

    Huang, S; Giovanelli, R; Brinchmann, J; Stierwalt, S; Neff, S G

    2012-01-01

    We examine the global properties of the stellar and HI components of 229 low HI mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with HI masses < 10^{7.7} M_sun and HI line widths < 80 km s^{-1}. SDSS data are combined with photometric properties derived from GALEX to derive stellar masses (M_*) and star formation rates (SFRs) by fitting their UV-optical spectral energy distributions (SEDs). In optical images, many of the ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs) and estimates of their SFRs and M_* obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR distribution at M_* < 10^8 M_sun is driven by a set of dwarf galaxies that have low gas fractions and SSFRs; some of t...

  1. Dynamics of exciplex formation in rare gas media

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Lorenzo, German, E-mail: grojas37@gmail.com [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba)] [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rubayo-Soneira, Jesus [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba); Alberti, Sebastian Fernandez [Centro de Estudios e Investigaciones, Universidad Nacional de Quilmes, Roque Saenz Pena 180, Bernal B1876BXD (Argentina)

    2009-07-30

    A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ({sup 1}S{sub 0} {yields} {sup 3}P{sub 1}) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its {sup 3}P{sub 1} electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg{sup *}-Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

  2. 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.

  3. 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

  4. 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

  5. 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 ...

  6. 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.

  7. Paraselectivity and Formation of Aromatic Hydrocarbons over ZSM-5 Type Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Unneberg, E.

    1996-12-31

    The zeolite ZSM-5, patented by Mobil Oil Corporation in 1972, is able to convert methanol to gasoline (MTG) and water. Due to the size of the channels, undesired hydrocarbons larger than C{sub 11} are not present in the mixture, and a high octane gasoline is obtained. This has aroused a great deal of interest in the ZSM-5. Rather than being concerned with energy considerations, this doctoral thesis describes syntheses of ZSM-5 and discusses the ZSM-5 as such and studies the possible paraselectivities in various reactions over the catalyst ZSM-5. 774 refs., 113 figs., 54 tabs.

  8. Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

    Science.gov (United States)

    Landera, Alexander

    2013-12-01

    Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn's moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    Science.gov (United States)

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  14. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    Directory of Open Access Journals (Sweden)

    Jianqiao Liu

    2017-08-01

    Full Text Available The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  15. 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.

  16. Shale gas characterization of the Dinder and Blue Nile Formations in the Blue Nile Basin, East Sudan

    Science.gov (United States)

    Shoieb, Monera Adam; Sum, Chow Weng; Bhattachary, Swapan Kumar; Abidin, Nor Syazwani Zainal; Abdelrahim, Omer Babiker

    2016-11-01

    The development of gas and oil in unconventional plays in United State and Northern Europe has affected the finances and the energy security. Geochanical properties of shale rocks can have a major impact on the efficiency of shale gas exploration. The goal of this study is to evaluate shale gas potentiality in the Blue Nile Basin, using samples from existing drilled wells. All the samples were analyzed in detail with the following organic geochemical techniques: total organic carbon (TOC), Rock-eval pyrolysis, to determine the quality and quantity of the organic matter. The total organic carbon (TOC) values for the shale intervals vary from 0.6 to 4.5weight% in FARASHA-1 Well, while in TAWAKUL-1 Well range from 0.4 to 2.4weight%, suggesting that fair to good source generative potential, as revealed by the S2 v's TOC plot. Hydrogen index (HI) values range from 12 to 182 mg HC/g TOC in the two wells, indicating type III and IV derived-input in the samples and their potential to generate gas. However, the Blue Nile and Dinder Formation have Tmax values in the range of 437 to 456°C, indicating early maturity in the oil window. Thus, higher maturity levels have affected the hydrocarbon generation potential and HI of the samples.

  17. Metallofullerene and fullerene formation from condensing carbon gas under conditions of stellar outflows and implication to stardust.

    Science.gov (United States)

    Dunk, Paul W; Adjizian, Jean-Joseph; Kaiser, Nathan K; Quinn, John P; Blakney, Gregory T; Ewels, Christopher P; Marshall, Alan G; Kroto, Harold W

    2013-11-01

    Carbonaceous presolar grains of supernovae origin have long been isolated and are determined to be the carrier of anomalous (22)Ne in ancient meteorites. That exotic (22)Ne is, in fact, the decay isotope of relatively short-lived (22)Na formed by explosive nucleosynthesis, and therefore, a selective and rapid Na physical trapping mechanism must take place during carbon condensation in supernova ejecta. Elucidation of the processes that trap Na and produce large carbon molecules should yield insight into carbon stardust enrichment and formation. Herein, we demonstrate that Na effectively nucleates formation of Na@C60 and other metallofullerenes during carbon condensation under highly energetic conditions in oxygen- and hydrogen-rich environments. Thus, fundamental carbon chemistry that leads to trapping of Na is revealed, and should be directly applicable to gas-phase chemistry involving stellar environments, such as supernova ejecta. The results indicate that, in addition to empty fullerenes, metallofullerenes should be constituents of stellar/circumstellar and interstellar space. In addition, gas-phase reactions of fullerenes with polycyclic aromatic hydrocarbons are investigated to probe "build-up" and formation of carbon stardust, and provide insight into fullerene astrochemistry.

  18. 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.

  19. Sedimentary facies and hydrocarbon accumulation in the Third member of Shahejie Formation in Beijing-Tianjin Depression

    Energy Technology Data Exchange (ETDEWEB)

    Jin, X.; Zhang, Z.

    1986-01-01

    The exploration practice in the Beijing-Tianjin area shows that the key point of improving seismic interpretation level in a complex district lies in the high accuracy of seismic work, extraction of available seismic information and the use of the comprehensive interpretation method basing on both structure interpretation and seismic stratigraphy. This paper presents the geological interpretation results of analyzing the Third member of Shahejie Formation in Beijing-Tianjin Depression by using the method stated above. It describes the seismic facies, sedimentary facies as well as the generation, accumulation and distribution of hydrocarbons, and points out that the lower part of the member is a subaqueous fan and point bar deposit, while the middle part is a fan-delta deposit. According to the thermo-evolution-profile and TTI estimated, it is assumed that the lower part of the member is source rock with sandstone development and is also a very good reservoir rock because of having two sets of source rock reservoir and seal rock. Having structures such as Jiuzhou anticline and its down dip and Liuquan fault structure, it is favorable for hydrocarbon accumulation. 4 figures.

  20. Formation of Combustible Hydrocarbons and H2 during Photocatalytic Decomposition of Various Organic Compounds under Aerated and Deaerated Conditions

    Directory of Open Access Journals (Sweden)

    Sylwia Mozia

    2014-11-01

    Full Text Available A possibility of photocatalytic production of useful aliphatic hydrocarbons and H2 from various organic compounds, including acetic acid, methanol, ethanol and glucose, over Fe-modified TiO2 is discussed. In particular, the influence of the reaction atmosphere (N2, air was investigated. Different gases were identified in the headspace volume of the reactor depending on the substrate. In general, the evolution of the gases was more effective in air compared to a N2 atmosphere. In the presence of air, the gaseous phase contained CO2, CH4 and H2, regardless of the substrate used. Moreover, formation of C2H6 and C3H8 in the case of acetic acid and C2H6 in the case of ethanol was observed. In case of acetic acid and methanol an increase in H2 evolution under aerated conditions was observed. It was concluded that the photocatalytic decomposition of organic compounds with simultaneous generation of combustible hydrocarbons and hydrogen could be a promising method of “green energy” production.

  1. Lanthanum oxide promoted rhodium/titania and rhodium-platinum/titania catalysts for alcohol formation from synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Bond, G.C.; Richards, D.G.

    1986-12-15

    TiO/sub 2/-supported Rh and Rh-Pt catalysts have been studied for the selective formation of oxygenates from synthesis gas. The addition of La/sub 2/O/sub 3/ as a promoter significantly increased the C/sub 2/H/sub 5/OH selectivities and formation rates. Pt addition increased the overall activity and in combination with La/sub 2/O/sub 3/ led to higher alcohol selectivities of 25% compared with 6% for an unpromoted Rh catalyst. A pronounced induction period was observed for CH/sub 3/OH and C/sub 2/H/sub 5/OH formation, attributed to changes in the nature of the catalytically active sites. A simple theoretical model is used to illustrate the parallel trends in C/sub 2/H/sub 5/OH and hydrocarbon formation after the induction period. Temperature-programmed reduction showed that the La/sub 2/O/sub 3/ increased the stability of Rh oxide. The main role of La/sub 2/O/sub 3/ appears to be promotion of the formation of the C/sub 2/H/sub 5/OH precursor, while Pt increased the rate of hydrogenation. 26 refs., 8 figs., 3 tabs.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Sedimentary facies and gas accumulation model of Lower Shihezi Formation in Shenguhao area, northern Ordos basin, China

    Science.gov (United States)

    Lin, Weibing; Chen, Lin; Lu, Yongchao; Zhao, Shuai

    2017-04-01

    . With the sea level gradually increasing, the lateral continuity of sandbody gradually became worse and gradually transformed into the pattern of single and isolated. The analysis of the typical gas accumulation profile of the Lower Shihezi Formation in the study area reveals that the formation of gas pools is mainly controlled by the distribution of sedimentary facies, faults and high point of structures. Generally, the types of gas pool developed in the study area can be divided into up dip pinch out gas pool, fault block gas pool and microstructure gas pool. The coal bearing strata of the underlying Taiyuan Formation and Shanxi Formation are the main hydrocarbon source rocks of the Lower Shihezi Formation. The gas transporting channel and lateral sealing composed by fault and sandbody constitute the key to form an effective gas pool, which usually made up of good lateral sealing, great thickness and good connectivity.

  8. HFC-134a refrigerant gas hydrate formation process and RIN model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the macroscopic visualization experiments of HFC-134a refrigerant gas hydrate formation are investigated. According to the macroscopic photos and Mori's microscopic photos of HFC-134a hydrate formation process, the mechanism of gas hydrate formation is analyzed.A random inducement nucleation model is presented to describe the hydrate formation process. The factors affecting the fractal growth dimension in the model, such as step,branch increment and angle, are discussed.``

  9. Experimental study of separation of ammonia synthesis vent gas by hydrate formation

    Institute of Scientific and Technical Information of China (English)

    Dong Taibin; Wang Leiyan; Liu Aixian; Guo Xuqiang; Ma Qinglan; Li Guowen; Sun Qiang

    2009-01-01

    Termodynamic data on methane hydrate formation in the presence of ammonia are very important for upgrading of ammonia synthesis vent gas using hydrate formation.This paper is focused on the formation conditions of methane hydrate in the presence of ammonia and the effects of gas-liquid ratio and temperature on the separation of vent gas by hydrate formation.Equilibrium data for methane hydrate within an ammonia mole concentration range from 1% to 5 % were obtained.The experimental results indicated that ammonia has an inhibitive effect on hydrate formation.The higher the ammonia concentration, the higher is the pressure reguired for methane hydrate formation would be.The primary experimental results showed that when volume ratio of gas to liquid was 80:1 and temperature was 283.15 K, total mole fraction of (H2+N2) in gas phase could reach 96.9 %.

  10. Comparing gas-phase and grain-catalyzed H2 formation

    CERN Document Server

    Glover, S C O

    2003-01-01

    Because H2 formation on dust grain surfaces completely dominates gas-phase H2 formation in local molecular clouds, it is often assumed that gas-phase formation is never important. In fact, it is the dominant mechanism in a number of cases. In this paper, I briefly summarize the chemistry of gas-phase H2 formation, and show that it dominates for dust-to-gas ratios less than a critical value D_cr. I also show that D_cr is simple to calculate for any given astrophysical situation, and illustrate this with a number of examples, ranging from H2 formation in warm atomic gas in the Milky Way to the formation of protogalaxies at high redshift.

  11. Petroleum systems and geologic assessment of undiscovered oil and gas, Cotton Valley group and Travis Peak-Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces of the northern Gulf Coast region. Chapters 1-7.

    Science.gov (United States)

    ,

    2006-01-01

    The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States. The USGS recently completed an assessment of undiscovered oil and gas potential of the Cotton Valley Group and Travis Peak and Hosston Formations in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces in the Gulf Coast Region (USGS Provinces 5048 and 5049). The Cotton Valley Group and Travis Peak and Hosston Formations are important because of their potential for natural gas resources. This assessment is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define one total petroleum system and eight assessment units. Seven assessment units were quantitatively assessed for undiscovered oil and gas resources.

  12. Arbuscular mycorrhizal fungi (AMF on a sandbank plant formation: ecology and potential for hydrocarbon oil mycorrhizoremediation

    Directory of Open Access Journals (Sweden)

    Ocimar Ferreira de Andrade

    2016-04-01

    Full Text Available The sources of contamination related to the exploration, production, storage, transport, distribution and disposal of petroleum, and its products, carry risks that threaten fragile coastal environments, little studied and, thus, in need of attention from the scientific community. On the other hand, symbiont mechanisms essential for the very existence of many plant species, and their relation to contaminated soils, remain unknown. Despite the identification of several species of AMF halophytes soil communities in sandbanks, one can infer their bioremediation potential from studies in other types of soil, which, however, report the same genera of fungi as participants in mycorrhizoremediation processes of polluted soil. This study focuses on the application of biotechnology using Arbuscular Mycorrhizal Fungi (AMF in soils impacted by petroleum hydrocarbons.

  13. 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.

  14. 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...

  15. 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)

  16. Vesicularity, bubble formation and noble gas fractionation during MORB degassing

    CERN Document Server

    Aubry, G; Guillot, B

    2013-01-01

    The objective of this study is to use molecular dynamics simulation (MD) to evaluate the vesicularity and noble gas fractionation, and to shed light on bubble formation during MORB degassing. A previous simulation study (Guillot and Sator (2011) GCA 75, 1829-1857) has shown that the solubility of CO2 in basaltic melts increases steadily with the pressure and deviates significantly from Henry's law at high pressures (e.g. 9.5 wt% CO2 at 50 kbar as compared with 2.5 wt% from Henry's law). From the CO2 solubility curve and the equations of state of the two coexisting phases (silicate melt and supercritical CO2), deduced from the MD simulation, we have evaluated the evolution of the vesicularity of a MORB melt at depth as function of its initial CO2 contents. An excellent agreement is obtained between calculations and data on MORB samples collected at oceanic ridges. Moreover, by implementing the test particle method (Guillot and Sator (2012) GCA 80, 51-69), the solubility of noble gases in the two coexisting pha...

  17. Surface films of short fluorocarbon-hydrocarbon diblocks studied by molecular dynamics simulations: Spontaneous formation of elongated hemimicelles.

    Science.gov (United States)

    Piñeiro, Angel; Prieto, Gerardo; Ruso, Juan M; Verdes, Pedro V; Sarmiento, Félix

    2009-01-15

    Using grazing incidence small-angle X-ray scattering (GISAXS), and atomic force microscopy (AFM) it has been recently demonstrated that linear fluorocarbon-hydrocarbon diblocks (FnHm) self-assemble in water/air interfaces forming elongated and circular hemimicelles. Those structures have been observed for diblocks with at least eight fluorinated carbons. Based on the lack of a collapse pressure for F6H16, and due to the fact that no stable surface pressure values are reached under compression, it has been concluded that these molecules do not form stable monolayers. It has been also suggested that F6H16 and shorter diblocks desorb from the water surface under compression. It is not easy to accept that a significant concentration of so hydrophobic molecules can be stable in aqueous solution even when the employed experimental techniques were not able to clearly detect a well defined structure on the interface. In the present work the adsorption and arrangement of F6H16 and F6H10 at the water surface are studied by molecular dynamics (MD) simulations as a function of the available area per molecule. Starting from a random mixture, the spontaneous formation of elongated hemimicelles is observed for both systems when the area per molecule is higher than approximately 50 A(2). For intermediate areas two pseudo-phases, one rich in hydrocarbons and the other with higher fluorocarbon concentration, are formed. For the systems with less than approximately 30 A(2) available per molecule the formation of multilayers is observed. This is the first time that the dynamics and structure of perfluoroalkane (PFA) films, and in particular of hemimicelles on a liquid surface, are observed and characterized at atomic level.

  18. 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)

  19. 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.

  20. Multi-scale gas flow in Bazhen formation shales

    Science.gov (United States)

    Vasilyev, R.; Gerke, K.; Korost, D. V.; Karsanina, M.; Balushkina, N. S.; Kalmikov, G. A.; Mallants, D.

    2013-12-01

    To perform geological surveys, estimate gas/oil productivity and create large-scale reservoir models, detailed information on reservoir rock properties is needed. Such information typically includes main reservoir properties such as absolute and relative permeability, formation factor, residual oil/water content, etc. The only available method to study all these properties directly is based on laboratory analysis of core material. Usually, only porosity measurements using such techniques as NMR and mercury porosimetry are applicable to study the structure of porous spaces filled with kerogen and bitumen. To measure porosity these organic materials should be extracted (usually by dissolution), a process which can result in sample destruction as some part of the organics is the part of the matrix (and also non-extractable during production). Thus, a pore-scale modelling approach in many cases is not only a valuable alternative, but also the only way to assess physical properties. Unlike core material, drilling cuts are almost always available for analysis and can be used for processing in the laboratory. The main aim of this work is to develop a framework for accessing unconventional reservoir rock properties using pore-scale modeling on 3D models of porous structure of cores or drilling cuts. To do so we combine detailed laboratory measurements on more than 20 samples of shales with X-ray micro-tomography and SEM to study micro and nano-porosity (including kerogen porosity). First, we show that in many cases it is not possible to measure petrophysical properties (e.g., gas permeability) in the laboratory, as dissolution procedures usually result in non-realistic values. Next samples with measurable properties were chosen and micro-tomography 3D structure data combined with SEM images was used to create representative network models. Macroporosity and distribution of different non-porosity domains (kerogen, pyrite, quartz, etc.) is extracted from X-ray tomography

  1. 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.

  2. The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: Environment of deposition, alteration and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G.; Wehner, H.; Kus, J. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Botz, R. [University Kiel, Geological-Paleontological Department, Olshausenstrasse 40-60, D-24118 Kiel (Germany); Berner, Z.; Stueben, D. [Technical University Karlsruhe, Institute for Mineralogy and Geochemistry, Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Al-Sayigh, A. [Sultan Qaboos University, Geological Dept. PO Box 36, Al-Khod (Oman)

    2007-10-01

    incursions make up a greater deal of the sedimentary record than mangrove swamps. Terra rossa paleosols mark the end of accumulation of organic material (OM) and herald supratidal conditions at the passage of Rusayl Formation into the overlying Seeb Formation. In the subtidal-supratidal cycles of lithofacies unit VIII the terra rossa horizons are thining upwards and become gradually substituted for by deep-water middle ramp sediments of lithofacies unit IX. Framboidal pyrite, (ferroan) dolomite with very little siderite are indicative of an early diagenetic alteration stage I under rather moderate temperatures of formation. During a subsequent stage II, an increase in the temperature of alteration was partly induced by burial and a high heat flow from the underlying Semail Ophiolite. Type-III kerogen originating from higher plants and, in addition, some marine biota gave rise to the generation of small amounts of soluble organic matter during this stage of diagenesis. The average reflectance of humic particles marks the beginning of the oil window and the production index reveals the existence of free hydrocarbons. Further uplift of the Eocene strata and oxidation during stage IIII caused veins of satin spar to form from organic sulfur and pyrite in the carbonaceous material. Lowering of the pH value of the pore fluid led to the precipitation of jarosite and a set of hydrated aluminum sulfates dependant upon the cations present in the wall rocks. AMD minerals (= acid mine drainage) are not very widespread in this carbonaceous series intercalated among calcareous rocks owing to the buffering effect of carbonate minerals. These carbonate-hosted carbonaceous rocks are below an economic level as far as the mining of coal is concerned, but deserves particular attention as source rocks for hydrocarbons in the Middle East, provided a higher stage of maturity is reached. (author)

  3. 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.

  4. VISUAL OBSERBATION OF HCFC141b GAS HYDRATE FORMATION/DECOMPOSITION PROCESS OUTSIDE OF A TUBE

    Institute of Scientific and Technical Information of China (English)

    谢应明; 郭开华; 樊栓狮; 梁德青; 顾建明

    2003-01-01

    In order to design a kind of heat exchanger suitable to the indirect-touched gas hydrate cool storage vessel, a visual observation of HCFC141b gas hydrate formation/decomposition process was presented through a self-designed small-scale visualization apparatus of gas hydrate cool storage. Based on the shooted photos and recorded temperatures, the formation/decomposition process of HCFC141b are described, some characteristics are concluded, and some suggestions of designing heat exchanger are indicated according to the specific characteristics of HCFC141b gas hydrate formation/decomposition process.

  5. Experimental and Modeling Studies on the Prediction of Gas Hydrate Formation

    Directory of Open Access Journals (Sweden)

    Jian-Yi Liu

    2015-01-01

    Full Text Available On the base of some kinetics model analysis and kinetic observation of hydrate formation process, a new prediction model of gas hydrate formation is proposed. The analysis of the present model shows that the formation of gas hydrate not only relevant with gas composition and free water content but also relevant with temperature and pressure. Through contrast experiment, the predicted result of the new prediction method of gas hydrate crystallization kinetics is close to measured result, it means that the prediction method can reflect the hydrate crystallization accurately.

  6. Formation and destruction mechanism as well as major controlling factors of the Silurian shale gas overpressure in the Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Shuangjian Li

    2016-08-01

    Full Text Available Taking the Well JY1 and Well PY1 in the Eastern Sichuan Basin as examples, the formation mechanism of shale gas overpressure was studied by using the cross plot of acoustic versus density logging data. During the processes of hydrocarbon generation and the uplifting, the pressure evolution of fluids in shale gas layers was reconstructed by fluid inclusions and PVTSIM software. The major factors controlling the evolution of shale gas overpressure were established according to the study of fracture, the timing of the uplifting, and episodes of tectonic deformation. Our results showed that the main mechanism of overpressure in the Silurian shale gas reservoirs in the Sichuan Basin was the fluid expansion, which was caused by hydrocarbon generation. Since the Yanshanian, the strata were uplifted and fluid pressure generally showed a decreasing trend. However, due to the low compression rebound ratio of shale gas reservoir rocks, poor connectivity of reservoir rocks, and low content of formation water and so on, such factors made fluid pressure decrease, but these would not be enough to make up the effects of strata erosion resulting in a further increase in fluid pressure in shale gas reservoirs during the whole uplifting processes. Since the Yanshanian, the Well PY1 zone had been reconstructed by at least three episodes of tectonic movement. The initial timing of the uplifting is 130 Ma. Compared to the former, the Well JY1 zone was firstly uplifted at 90 Ma, which was weakly reconstructed. As a result, low-angle fractures and few high resistance fractures developed in the Well JY1, while high-angle fractures and many high resistance fractures developed in the Well PY1. In totality, the factors controlling the overpressure preservation in shale gas reservoirs during the late periods include timing of late uplifting, superposition and reconstruction of stress fields, and development of high-angle fractures.

  7. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity. The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas. Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites) →first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores)→dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation. Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth. In a long-term closed system, only feld-spars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation. This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally. The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  8. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHU RuKai; ZOU CaiNeng; ZHANG Nai; WANG XueSong; CHENG Rong; LIU LiuHong; ZHOU ChuanMin; SONG LiHong

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity.The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas.Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites)→ first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores→ dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→ intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation.Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth.In a long-term closed system, only feldspars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation.This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally.The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  9. 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.

  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. Unraveling the Timing of Fluid Migration and Trap Formation in the Brooks Range Foothills: A Key to Discovering Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Catherine L. Hanks

    2008-12-31

    Naturally occurring fractures can play a key role in the evolution and producibility of a hydrocarbon accumulation. Understanding the evolution of fractures in the Brooks Range/Colville basin system of northern Alaska is critical to developing a better working model of the hydrocarbon potential of the region. This study addressed this problem by collecting detailed and regional data on fracture distribution and character, structural geometry, temperature, the timing of deformation along the Brooks Range rangefront and adjacent parts of the Colville basin, and the in situ stress distribution within the Colville basin. This new and existing data then were used to develop a model of how fractures evolved in northern Alaska, both spatially and temporally. The results of the study indicate that fractures formed episodically throughout the evolution of northern Alaska, due to a variety of mechanisms. Four distinct fracture sets were observed. The earliest fractures formed in deep parts of the Colville basin and in the underlying Ellesmerian sequence rocks as these rocks experienced compression associated with the growing Brooks Range fold-and-thrust belt. The orientation of these deep basin fractures was controlled by the maximum in situ horizontal stress in the basin at the time of their formation, which was perpendicular to the active Brooks Range thrust front. This orientation stayed consistently NS-striking for most of the early history of the Brooks Range and Colville basin, but changed to NW-striking with the development of the northeastern Brooks Range during the early Tertiary. Subsequent incorporation of these rocks into the fold-and-thrust belt resulted in overprinting of these deep basin fractures by fractures caused by thrusting and related folding. The youngest fractures developed as rocks were uplifted and exposed. While this general order of fracturing remains consistent across the Brooks Range and adjacent Colville basin, the absolute age at any one

  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. Gas-solid flow field numerical simulation of different feeding and returning formations of flue-gas circulating fluidized bed

    Institute of Scientific and Technical Information of China (English)

    WANG Hu

    2012-01-01

    3D Euler double-fluid model was applied and three different feedstocks and reverts formations were simulated.By calculating and analyzing the state of gas and solid fluxion in absorber using three different methods of the feedstocks and reverts in recirculating fluidized bed,described the behavior of gas and solid through the gas-phase velocity,turbulence intensity,gas-solid sliding velocity,and density of particles.The results show that the feedstocks and reverts enters into absorption tower through two symmetrical feedings and are mixed with flue gas.Based on the respective analysis of each model and the comparison analysis of the three models,this paper drew conclusions.The turbulence intensity of absorption tower is high,gas-solid sliding speed is big,and granule concentration near the axis is high,which has advantages for desulfurization and improving the utilization rate of absorbent.

  17. Formation of secondary organic aerosols from gas-phase emissions of heated cooking oils

    Science.gov (United States)

    Liu, Tengyu; Li, Zijun; Chan, ManNin; Chan, Chak K.

    2017-06-01

    Cooking emissions can potentially contribute to secondary organic aerosol (SOA) but remain poorly understood. In this study, formation of SOA from gas-phase emissions of five heated vegetable oils (i.e., corn, canola, sunflower, peanut and olive oils) was investigated in a potential aerosol mass (PAM) chamber. Experiments were conducted at 19-20 °C and 65-70 % relative humidity (RH). The characterization instruments included a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). The efficiency of SOA production, in ascending order, was peanut oil, olive oil, canola oil, corn oil and sunflower oil. The major SOA precursors from heated cooking oils were related to the content of monounsaturated fat and omega-6 fatty acids in cooking oils. The average production rate of SOA, after aging at an OH exposure of 1. 7 × 1011 molecules cm-3 s, was 1. 35 ± 0. 30 µg min-1, 3 orders of magnitude lower compared with emission rates of fine particulate matter (PM2. 5) from heated cooking oils in previous studies. The mass spectra of cooking SOA highly resemble field-derived COA (cooking-related organic aerosol) in ambient air, with R2 ranging from 0.74 to 0.88. The average carbon oxidation state (OSc) of SOA was -1.51 to -0.81, falling in the range between ambient hydrocarbon-like organic aerosol (HOA) and semi-volatile oxygenated organic aerosol (SV-OOA), indicating that SOA in these experiments was lightly oxidized.

  18. The State of the Gas and the Relation Between Gas and Star Formation at Low Metallicity: the Small Magellanic Cloud

    CERN Document Server

    Bolatto, Alberto D; Jameson, Katherine; Ostriker, Eve; Gordon, Karl; Lawton, Brandon; Stanimirovic, Snezana; Israel, Frank P; Madden, Suzanne C; Hony, Sacha; Sandstrom, Karin M; Bot, Caroline; Rubio, Monica; Winkler, P Frank; Roman-Duval, Julia; van Loon, Jacco Th; Oliveira, Joana M; Indebetouw, Remy

    2011-01-01

    We compare atomic gas, molecular gas, and the recent star formation rate (SFR) inferred from H-alpha in the Small Magellanic Cloud (SMC). By using infrared dust emission and local dust-to-gas ratios, we construct a map of molecular gas that is independent of CO emission. This allows us to disentangle conversion factor effects from the impact of metallicity on the formation and star formation efficiency of molecular gas. On scales of 200 pc to 1 kpc we find a characteristic molecular gas depletion time of ~1.6 Gyr, similar to that observed in the molecule-rich parts of large spiral galaxies on similar spatial scales. This depletion time shortens on much larger scales to ~0.6 Gyr because of the presence of a diffuse H-alpha component, and lengthens on much smaller scales to ~7.5 Gyr because the H-alpha and H2 distributions differ in detail. We estimate the systematic uncertainties in our measurement to be a factor of 2-3. We suggest that the impact of metallicity on the physics of star formation in molecular ga...

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. Hydrate Formation/Dissociation in (Natural Gas + Water + Diesel Oil Emulsion Systems

    Directory of Open Access Journals (Sweden)

    Chang-Yu Sun

    2013-02-01

    Full Text Available Hydrate formation/dissociation of natural gas in (diesel oil + water emulsion systems containing 3 wt% anti-agglomerant were performed for five water cuts: 5, 10, 15, 20, and 25 vol%. The natural gas solubilities in the emulsion systems were also examined. The experimental results showed that the solubility of natural gas in emulsion systems increases almost linearly with the increase of pressure, and decreases with the increase of water cut. There exists an initial slow hydrate formation stage for systems with lower water cut, while rapid hydrate formation takes place and the process of the gas-liquid dissolution equilibrium at higher water cut does not appear in the pressure curve. The gas consumption amount due to hydrate formation at high water cut is significantly higher than that at low water cut. Fractional distillation for natural gas components also exists during the hydrate formation process. The experiments on hydrate dissociation showed that the dissociation rate and the amount of dissociated gas increase with the increase of water cut. The variations of temperature in the process of natural gas hydrate formation and dissociation in emulsion systems were also examined.

  7. New Insight into the Kinetics of Deep Liquid Hydrocarbon Cracking and Its Significance

    Directory of Open Access Journals (Sweden)

    Wenzhi Zhao

    2017-01-01

    Full Text Available The deep marine natural gas accumulations in China are mainly derived from the cracking of liquid hydrocarbons with different occurrence states. Besides accumulated oil in reservoir, the dispersed liquid hydrocarbon in and outside source also is important source for cracking gas generation or relayed gas generation in deep formations. In this study, nonisothermal gold tube pyrolysis and numerical calculations as well as geochemical analysis were conducted to ascertain the expulsion efficiency of source rocks and the kinetics for oil cracking. By determination of light liquid hydrocarbons and numerical calculations, it is concluded that the residual bitumen or hydrocarbons within source rocks can occupy about 50 wt.% of total oil generated at oil generation peak. This implies that considerable amounts of natural gas can be derived from residual hydrocarbon cracking and contribute significantly to the accumulation of shale gas. Based on pyrolysis experiments and kinetic calculations, we established a model for the cracking of oil and its different components. In addition, a quantitative gas generation model was also established to address the contribution of the cracking of residual oil and expulsed oil for natural gas accumulations in deep formations. These models may provide us with guidance for gas resource evaluation and future gas exploration in deep formations.

  8. Increasing the storage capacity and selectivity in the formation of natural gas hydrates using porous media

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour Zanjani, N.; Zarringhalam Moghaddam, A.; Mohammad-Taheri, M. [Tarbiat Modares University, Chemical Engineering Department, Tehran (Iran, Islamic Republic of); Nazari, K. [Research Institute of Petroleum Industry, Chemistry and Petrochemical Research Division, Tehran (Iran, Islamic Republic of)

    2012-11-15

    Formation of a gas hydrate with two different gas compositions (natural gas and a mixture of methane-ethane-propane) was investigated using a special method of producing the hydrate from ice. Gas uptake, splitting the fraction of each component between the gas phase and hydrate phase, and purification of methane were studied in the presence of silica-based porous media. Addition of a small amount of colloidal silica media increased considerably the gas storage capacity of the hydrate phase. In the presence of silica-based porous media, the purification factor of CH{sub 4} became significantly higher. The results can provide the basis for the storage of natural gas in hydrate form and application of the hydrate-based gas separation technology to achieve methane with high purity from natural gas. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    Science.gov (United States)

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-10-01

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn't cause the gas bubble alignment, and fast 1-D migration of interstitials along directions in the body-centered cubic U matrix causes the gas bubble alignment along directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  10. 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.

  11. 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.

  12. Formation of van der Waals molecules in buffer gas cooled magnetic traps

    CERN Document Server

    Brahms, N; Zhang, P; los, J K; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-01-01

    We show that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10^12 cm^-3. We explore the spin relaxation of these molecules in buffer gas loaded magnetic traps, and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T^6 thermal dependence of spin change in buffer gas trapped silver (Ag) is accounted for by the formation and spin change of AgHe, thus providing evidence for molecular formation in a buffer gas trap.

  13. Formation process of structure 1 and 2 gas hydrates discovered in Kukuy, Lake Baikal

    Energy Technology Data Exchange (ETDEWEB)

    Hachikubo, A.; Sakagami, H.; Minami, H.; Nunokawa, Y.; Yamashita, S.; Takahashi, N.; Shoji, H. [Kitami Inst. of Technology, Kitami (Japan); Kida, M. [Advanced Industrial Science and Technology, Toyohira-ku, Sapporo, Hokkaido (Japan); Krylov, A. [All-Russia Research Inst. for Geology and Mineral Resources of the Ocean, St. Petersburg (Russian Federation); Khlystov, O.; Zemskaya, T. [Limnological Inst., Irkutsk (Russian Federation); Manakov, A. [Nikolaev Inst. of Inorganic Chemistry, Novosibirsk (Russian Federation); Kalmychkov, G. [Vinogradov Inst. of Geochemistry, Irkutsk (Russian Federation); Poort, J. [Ghent Univ., Krijgslaan (Belgium). Renard Centre of Marine Geology

    2008-07-01

    This study investigated the formation process of different crystal structures of gas hydrates found in Kukuy K-2, Lake Baikal, Russia. Gas compositions and isotopic ratios were taken from hydrate-bound gas and from dissolved gas in sediments by a headspace gas method. Structure 1 and 2 gas hydrates were observed in the same sediment cores of a mud volcano in the Kukuy Canyon, Lake Baikal. This paper discussed the results of the observations. The structure 2 gas hydrate contained about 13-15 per cent ethane, whereas the structure 1 gas hydrate contained about 1-5 per cent ethane and was placed beneath the structure 2 gas hydrate. The paper discussed the measurement of isotopic composition of dissociation gas from both type gas hydrates and dissolved gas in pore water. The paper also reported on these results. It was concluded that the current gas dissolved in pore water was not the source of these gas hydrates of both crystal structures in Kukuy K-2 mud volcano in Lake Baikal. In addition, isotopic data also provided useful information on how the double structure gas hydrates formed. 18 refs., 4 figs.

  14. Formation of unsaturated hydrocarbons in interstellar ice analogs by cosmic rays

    OpenAIRE

    Pilling, S.; Andrade, D. P. P.; Da Silveira, E.F.; Rothard, H.; Domaracka, A.; Boduch, P.

    2012-01-01

    The formation of double and triple C-C bonds from the processing of pure c-C6H12 (cyclohexane) and mixed H2O:NH3:c-C6H12 (1:0.3:0.7) ices by highly-charged, and energetic ions (219 MeV O^{7+} and 632 MeV Ni^{24+}) is studied. The experiments simulate the physical chemistry induced by medium-mass and heavy-ion cosmic rays in interstellar ices analogs. The measurements were performed inside a high vacuum chamber at the heavy-ion accelerator GANIL (Grand Accel\\'erat\\'eur National d'Ions Lourds) ...

  15. Model compound study of the pathways for aromatic hydrocarbon formation in soot.

    Energy Technology Data Exchange (ETDEWEB)

    Winans, R. E.; Tomczyk, N. A.; Hunt, J. E.; Solum, M. S.; Pugmire, R. J.; Jiang, Y. J.; Fletcher, T. H.; Univ. of Utah; Brigham Young Univ.

    2007-09-01

    As a follow-up of previous work on the flame pyrolysis of biphenyl and pyrene, a more detailed analysis of the pyrolytic products has been done using additional NMR data obtained on the whole soot sample correlated with detailed high-resolution and GC mass spectrometry data on the solvent-extracted portion of the same samples. These latter data complement the earlier NMR data with details of the pre-sooting structures, referred to as 'young soot', in pyrolyzed biphenyl samples collected at 1365, 1410, and 1470 K and pyrene at 1410 and 1470 K. The data reveal the roles played by free-radical-assisted polymerization reactions as well as the hydrogen-abstraction carbon-addition (HACA) reactions for the biphenyl pyrolysis. The mass spectroscopy data of pyrene describe a much different set of reactions due to polymerization which employs free-radical reactions of the pyrene due primarily to hydrogen abstraction followed by the formation of biaryl linkages at mass numbers up to five times that of the parent pyrene. Conceptual schema of reaction mechanisms are proposed to explain the formation pathways to materials detected in the soot extracts.

  16. Model compound study of the pathways for aromatic hydrocarbon formation in soot

    Energy Technology Data Exchange (ETDEWEB)

    Randall E. Winans; Nancy A. Tomczyk; Jerry E. Hunt; Mark S. Solum; Ronald J. Pugmire; Yi Jin Jiang; Thomas H. Fletcher [University of Utah, Salt Lake City, UT (United States). Department of Chemistry

    2007-07-01

    A previous study was conducted to determine the early sooting pathways of biphenyl and pyrene. Soot/pah samples from biphenyl were collected in a fuel-rich flat-flame burner at temperatures of 1365, 1410, and 1470 K and from pyrene at 1410 and 1470K. A more detailed analysis of the pyrolitic products has been performed using additional NMR data obtained on the whole soot sample correlated with detailed high resolution as well as GC mass spectrometry data on the solvent extracted portion of the same samples. These latter data complement the earlier NMR data with details of the pre-sooting structures, referred to as 'young soot.' The data reveal the roles played by free radical assisted polymerization reactions as well as the hydrogen abstraction carbon addition (HACA) reactions for the biphenyl pyrolysis. The mass spectroscopy data of pyrene describe a much different set of reactions due to polymerization which employs free radical reactions of the pyrene due primarily to hydrogen abstraction followed by the formation of biaryl linkages at mass numbers up to five times that of the parent pyrene. Conceptual schema of reaction mechanisms are proposed to explain the formation pathways to materials detected in the soot extracts. 21 refs., 6 figs., 4 tabs.

  17. Hydrocarbon source potential of the Tanezzuft Formation, Murzuq Basin, south-west Libya: An organic geochemical approach

    Science.gov (United States)

    El Diasty, W. Sh.; El Beialy, S. Y.; Anwari, T. A.; Batten, D. J.

    2017-06-01

    A detailed organic geochemical study of 20 core and cuttings samples collected from the Silurian Tanezzuft Formation, Murzuq Basin, in the south-western part of Libya has demonstrated the advantages of pyrolysis geochemical methods for evaluating the source-rock potential of this geological unit. Rock-Eval pyrolysis results indicate a wide variation in source richness and quality. The basal Hot Shale samples proved to contain abundant immature to early mature kerogen type II/III (oil-gas prone) that had been deposited in a marine environment under terrigenous influence, implying good to excellent source rocks. Strata above the Hot Shale yielded a mixture of terrigenous and marine type III/II kerogen (gas-oil prone) at the same maturity level as the Hot Shale, indicating the presence of only poor to fair source rocks.

  18. Reducing Mechanical Formation Damage by Minimizing Interfacial Tension and Capillary Pressure in Tight Gas

    Science.gov (United States)

    Ahmed, Arshad; Talib Shuker, Muhannad; Rehman, Khalil; Bahrami, Hassan; Memon, Muhammad Khan

    2013-12-01

    Tight gas reservoirs incur problems and significant damage caused by low permeability during drilling, completion, stimulation and production. They require advanced improvement techniques to achieve flow gas at optimum rates. Water blocking damage (phase Trapping/retention of fluids) is a form of mechanical formation damage mechanism, which is caused by filtrate invasion in drilling operations mostly in fracturing. Water blocking has a noticeable impact on formation damage in gas reservoirs which tends to decrease relative permeability near the wellbore. Proper evaluation of damage and the factors which influence its severity is essential to optimize well productivity. Reliable data regarding interfacial tension between gas and water is required in order to minimize mechanical formation damage potential and to optimize gas production. This study was based on the laboratory experiments of interfacial tension by rising drop method between gas-brine, gas-condensate and gas-brine. The results showed gas condensate has low interfacial tension value 6 - 11 dynes/cm when compared to gas-brine and gas- diesel which were 44 - 58 dynes/cm and 14 - 19 dynes/cm respectively. In this way, the capillary pressure of brine-gas system was estimated as 0.488 psi, therefore diesel-gas system was noticed about 0.164 psi and 0.098 psi for condensate-gas system. A forecast model was used by using IFT values to predict the phase trapping which shows less severe phase trapping damage in case of condensate than diesel and brine. A reservoir simulation study was also carried out in order to better understand the effect of hysteresis on well productivity and flow efficiency affected due to water blocking damage in tight gas reservoirs.

  19. Analysis of hydrocarbons generated in coalbeds

    Science.gov (United States)

    Butala, Steven John M.

    This dissertation describes kinetic calculations using literature data to predict formation rates and product yields of oil and gas at typical low-temperature conditions in coalbeds. These data indicate that gas formation rates from hydrocarbon thermolysis are too low to have generated commercial quantities of natural gas, assuming bulk first-order kinetics. Acid-mineral-catalyzed cracking, transition-metal-catalyzed hydrogenolysis of liquid hydrocarbons, and catalyzed CO2 hydrogenation form gas at high rates. The gaseous product compositions for these reactions are nearly the same as those for typical natural coalbed gases, while those from thermal and catalytic cracking are more representative of atypical coalbed gases. Three Argonne Premium Coals (Upper-Freeport, Pittsburgh #8 and Lewiston-Stockton) were extracted with benzene in both Soxhlet and elevated pressure extraction (EPE) systems. The extracts were compared on the basis of dry mass yield and hydrocarbon profiles obtained by gas chromatography/mass spectrometry. The dry mass yields for the Upper-Freeport coal gave consistent results by both methods, while the yields from the Pittsburgh #8 and Lewiston-Stockton coals were greater by the EPE method. EPE required ˜90 vol. % less solvent compared to Soxhlet extraction. Single-ion-chromatograms of the Soxhlet extracts all exhibited bimodal distributions, while those of the EPE extracts did not. Hydrocarbons analyzed from Greater Green River Basin samples indicate that the natural oils in the basin originated from the coal seams. Analysis of artificially produced oil indicates that hydrous pyrolysis mimics generation of C15+ n-alkanes, but significant variations were found in the branched alkane, low-molecular-weight n-alkanes, and high-molecular-weight aromatic hydrocarbon distributions.

  20. Hydrocarbon source potential of the Santiago Formation, Oriente Basin, SE of Ecuador

    Science.gov (United States)

    Gaibor, J.; Hochuli, J. P. A.; Winkler, W.; Toro, J.

    2008-03-01

    The Santiago Formation (Late Hettangian-Sinemurian), described in the area of Santiago in the Oriente Basin of eastern Ecuador, consists of three distinct sedimentary members. The Santiago River Member is composed of limestones and calcareous sandstones. The Yuquianza Member is a monotonous sequence of black shales. The Patuca Member consists of a sequence of sandstones, greywackes, and shales, intercalated with lava flows and dikes. The fine-grained sediments of the three members are characterized by a high content of particulate organic matter (POM). Palynofacies and rock-eval analyses indicate the predominance of kerogen types II and III, with HI values that indicate a moderate to low source potential. At the type locality, the organic matter is thermally mature and locally overmatures.

  1. Enhanced reactivity of hydroxylated polycyclic aromatic hydrocarbons to birnessite in soil: reaction kinetics and nonextractable residue formation.

    Science.gov (United States)

    Jung, Jae-Woong; Lee, Seunghwan; Ryu, Hyerim; Nam, Kyoungphile; Kang, Ki-Hoon

    2008-05-01

    Phenanthrene and pyrene were not transformed by birnessite (delta-MnO2) in the presence of phenol. The phenoxy radicals generated from phenol by birnessite did not act as a mediator for polycyclic aromatic hydrocarbon radical reaction under the studied conditions. In contrast, 9-hydroxyphenanthrene and 1-hydroxypyrene were remarkably sensitive to birnessite. The disappearance patterns of the test compounds both in the aqueous phase and soil followed first-order kinetics, with a linear relationship found between the rate constants and the surface area of birnessite. Moreover, the data indicated that the reaction was faster in the presence of soil than in the aqueous phase probably because of the presence of hydroxyl groups in soil organic matter. Sequential solvent extraction was not successful in the recovery of 9-hydroxyphenanthrene from the birnessite-treated soil samples, and capillary electrophoresis data suggest the formation of nonextractable residues of the compound in soil. In addition, the acute toxicity determined by Microtox declined approximately 8.3 times in the soil samples treated with birnessite compared to untreated samples, demonstrating that the toxic compound was no longer present as its parent form.

  2. An experimental investigation into the formation of polycyclic-aromatic hydrocarbons (PAH) from pyrolysis of biomass materials

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, T.; Sharma, R.; Hajaligol, M. [Philip Morris USA, Richmond, VA (United States). Research Center

    2001-10-09

    The formation of polycyclic-aromatic hydrocarbons (PAH) from the pyrolysis of cellulose, pectin and chlorogenic acid was studied. The primary product, mostly primary volatile tar, was exposed to a higher thermal severity i.e. high temperatures and long residence times. The reactor setup consisted of a quartz tube with two zones, zone I and II, each heated and controlled separately. Zone I was used to first pyrolyse the substrate at 300{degree}C to produce a low temperature tar (LTT) as well as to pyrolyse the product char at 600{degree}C to produce a high temperature tar (HTT). The LTT and HTT were then subjected to a high thermal severity in the second zone (zone II) where the temperature was varied between 700 and 850{degree}C. The residence time of the volatiles in zone II was varied between ca. 90 and 1400 ms (calculated at 800{degree}C). The results show that the yield of most PAHs increased with temperature, except in a few cases where the yield of two- and three-ring PAHs exhibited a maximum. PAHs yields also generally increased as the residence time was increased from 90 to 1400 ms at 800{degree}C. 19 refs., 9 figs., 2 tabs.

  3. Effect of chemistry and turbulence on NO formation in oxygen-natural gas flames

    Science.gov (United States)

    Samaniego, J. -M.; Egolfopoulos, F. N.; Bowman, C. T.

    1996-01-01

    The effects of chemistry and turbulence on NO formation in oxygen-natural turbulent diffusion flames gas flames have been investigated. The chemistry of nitric oxides has been studied numerically in the counterflow configuration. Systematic calculations with the GRI 2.11 mechanism for combustion of methane and NO chemistry were conducted to provide a base case. It was shown that the 'simple' Zeldovich mechanism accounts for more than 75% of N2 consumption in the flame in a range of strain-rates varying between 10 and 1000 s-l. The main shortcomings of this mechanism are: 1) overestimation (15%) of the NO production rate at low strain-rates because it does not capture the reburn due to the hydrocarbon chemistry, and 2) underestimation (25%) of the NO production rate at high strainrates because it ignores NO production through the prompt mechanism. Reburn through the Zeldovich mechanism alone proves to be significant at low strain-rates. A one-step model based on the Zeldovich mechanism and including reburn has been developed. It shows good agreement with the GRI mechanism at low strain-rates but underestimates significantly N2 consumption (about 50%) at high strain-rates. The role of turbulence has been assessed by using an existing 3-D DNS data base of a diffusion flame in decaying turbulence. Two PDF closure models used in practical industrial codes for turbulent NO formation have been tested. A simpler version of the global one-step chemical scheme for NO compared to that developed in this study was used to test the closure assumptions of the PDF models, because the data base could not provide all the necessary ingredients. Despite this simplification, it was possible to demonstrate that the current PDF models for NO overestimate significantly the NO production rate due to the fact that they neglect the correlations between the fluctuations in oxygen concentration and temperature. A single scalar PDF model for temperature that accounts for such correlations based

  4. 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.

  5. 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.

  6. Distribution of some hydrocarbons in ambient air near Delft and the influence on the formation of secondary air pollutants

    NARCIS (Netherlands)

    Bos, R.; Guicherit, R.; Hoogeveen, A.

    1977-01-01

    The relative concentrations of hydrocarbons in the atmosphere may provide information concerning their origin. It appears that the hydrocarbon composition measured in Delft (The Netherlands) is entirely different for northern and southern wind directions. This points to different sources. The most

  7. CO2 + N2O mixture gas hydrate formation kinetics and effect of soil minerals on mixture-gas hydrate formation process

    Science.gov (United States)

    Enkh-Amgalan, T.; Kyung, D.; Lee, W.

    2012-12-01

    CO2 mitigation is one of the most pressing global scientific topics in last 30 years. Nitrous oxide (N2O) is one of the main greenhouse gases (GHGs) defined by the Kyoto Protocol and its global warming potential (GWP) of one metric ton is equivalent to 310 metric tons of CO2. They have similar physical and chemical properties and therefore, mixture-gas (50% CO2 + 50% N2O) hydrate formation process was studied experimentally and computationally. There were no significant research to reduce N20 gas and we tried to make hydrate to mitigate N20 and CO2 in same time. Mixture gas hydrate formation periods were approximately two times faster than pure N2O hydrate formation kinetic in general. The fastest induction time of mixture-gas hydrate formation observed in Illite and Quartz among various soil mineral suspensions. It was also observed that hydrate formation kinetic was faster with clay mineral suspensions such as Nontronite, Sphalerite and Montmorillonite. Temperature and pressure change were not significant on hydrate formation kinetic; however, induction time can be significantly affected by various chemical species forming under the different suspension pHs. The distribution of chemical species in each mineral suspension was estimated by a chemical equilibrium model, PHREEQC, and used for the identification of hydrate formation characteristics in the suspensions. With the experimental limitations, a study on the molecular scale modeling has a great importance for the prediction of phase behavior of the gas hydrates. We have also performed molecular dynamics computer simulations on N2O and CO2 hydrate structures to estimate the residual free energy of two-phase (hydrate cage and guest molecule) at three different temperature ranges of 260K, 273K, and 280K. The calculation result implies that N2O hydrates are thermodynamically stable at real-world gas hydrate existing condition within given temperature and pressure. This phenomenon proves that mixture-gas could be

  8. Concretions and concretion analysis of oil and gas formations, Tyumen, 11-13 Oct 1983

    Energy Technology Data Exchange (ETDEWEB)

    Nesterov, I.I.; Sidorenkov, A.I.; Vysotskiy, V.N.; Zaritskiy, P.V.

    1984-01-01

    Information about the 4th All-Union Scientific Conference on ''concretions and concretion analysis of oil and gas formations'' which took place from 11 to 13 October 1983 in Tyumen is provided.

  9. Experiments in chondrule formation: simulations of gas-grain collisions using plasma arcs

    OpenAIRE

    Morlock, Andreas; Sutton, Yvonne; Braithwaite, Nicholas St.J.; Grady, M.M.

    2010-01-01

    To investigate the formation of chondrules in gas-grain collisions, we conducted experiments where mineral mixtures were melted in plasma arcs. First results already show silicate-rich spheres quite similar to chondrules.

  10. Pizza or Pancake? Formation Models of Gas Escape Biosignatures in Terrestrial and Martian Sediments

    Science.gov (United States)

    Bonaccorsi, R.; Fairen, A. G.; Baker, L.; McKay, C. P.; Willson, D.

    2016-05-01

    Fine-grained sedimentary hollowed structures were imaged in Gale Crater, but no biomarkers identified to support biology. Our observation-based (gas escape) terrestrial model could inform on possible martian paleoenvironments at time of formation.

  11. The experimental modeling of gas percolation mechanisms in a coal-measure tight sandstone reservoir: A case study on the coal-measure tight sandstone gas in the Upper Triassic Xujiahe Formation, Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Shizhen Tao

    2016-12-01

    Full Text Available Tight sandstone gas from coal-measure source rock is widespread in China, and it is represented by the Xujiahe Formation of the Sichuan Basin and the Upper Paleozoic of the Ordos Basin. It is affected by planar evaporative hydrocarbon expulsion of coal-measure source rock and the gentle structural background; hydrodynamics and buoyancy play a limited role in the gas migration-accumulation in tight sandstone. Under the conditions of low permeability and speed, non-Darcy flow is quite apparent, it gives rise to gas-water mixed gas zone. In the gas displacing water experiment, the shape of percolation flow curve is mainly influenced by core permeability. The lower the permeability, the higher the starting pressure gradient as well as the more evident the non-Darcy phenomenon will be. In the gas displacing water experiment of tight sandstone, the maximum gas saturation of the core is generally less than 50% (ranging from 30% to 40% and averaging at 38%; it is similar to the actual gas saturation of the gas zone in the subsurface core. The gas saturation and permeability of the core have a logarithm correlation with a correlation coefficient of 0.8915. In the single-phase flow of tight sandstone gas, low-velocity non-Darcy percolation is apparent; the initial flow velocity (Vd exists due to the slippage effect of gas flow. The shape of percolation flow curve of a single-phase gas is primarily controlled by core permeability and confining pressure; the lower the permeability or the higher the confining pressure, the higher the starting pressure (0.02–0.08 MPa/cm, whereas, the higher the quasi-initial flow speed, the longer the nonlinear section and the more obvious the non-Darcy flow will be. The tight sandstone gas seepage mechanism study shows that the lower the reservoir permeability, the higher the starting pressure and the slower the flow velocity will be, this results in the low efficiency of natural gas migration and accumulation as well as

  12. Quantum Dew Formation of quantum liquid in a nonequilibrium Bose gas

    CERN Document Server

    Khlebnikov, S Yu

    2000-01-01

    We consider phase separation in nonequilibrium Bose gas with an attractive interaction between the particles. Using numerical integrations on a lattice, we show that the system evolves into a state that contains drops of Bose-Einstein condensate suspended in uncondensed gas. When the initial gas is sufficiently rarefied, the rate of formation of this quantum dew scales with the initial density as expected for a process governed by two-particle collisions.

  13. An Introverted Starburst: Gas and SSC Formation in NGC 5253

    Science.gov (United States)

    Turner, J. L.; Beck, S. C.

    2004-06-01

    High resolution Brackett line spectroscopy with the Keck Telescope reveals relatively narrow recombination lines toward the embedded young super star cluster nebula in NGC 5253. The gas within this nebula is almost certainly gravitationally bound by the massive and compact young star cluster.

  14. An apparent permeability model of shale gas under formation conditions

    Science.gov (United States)

    Chen, Peng; Jiang, Shan; Chen, Yan; Wang, Shanshan

    2017-08-01

    There are various types of pores in shale, mainly consisting of nanopores and micropores, causing flow regime variations and apparent permeability changes during the development of the reservoir. In this paper, a Knudsen number calculation model is proposed with the actual conditions of gas in a shale reservoir. Then, based on the distribution of pores in shale, an apparent permeability model is established using hydrodynamics, and a calculation method is put forward for the actual permeability of a reservoir. Finally, the Knudsen number model and the permeability correction coefficient model are used to analyze the flow regime and permeability correction coefficients in pores during the development of the shale gas reservoir. Results show that with a decreasing of pressure, the Knudsen number increases, the flow regime changes from continuous flow and slip flow to transition flow or free molecular flow. When the Knudsen number is Kn > 0.1, and with a further increasing of Kn, gas molecule slippage greatly intensifies and the permeability correction coefficient K app/Kd significantly increases. While the Knudsen number increases, the permeability correction coefficient significantly increases in the micropores and the small pores, but this does not appear in the macropores and the mesopores. These results can be used to guide flow regime analysis and production forecasting in shale gas reservoirs.

  15. The formation and physical origin of highly ionized cooling gas

    CERN Document Server

    Bordoloi, Rongmon; Norman, Colin A

    2016-01-01

    We present a physically clear cooling flow theory that explains the origin of warm diffuse gas seen primarily as highly ionized absorption line systems in the spectra of background sources. We predict the observed column densities of several highly ionized transitions such as O VI, O VII, Ne VIII, N V, and Mg X; and present a unified comparison of the model predictions with absorption lines seen in the Milky Way disk, Milky Way halo, starburst galaxies, the circumgalactic medium and the intergalactic medium at low and high redshifts. We show that diffuse gas seen in such diverse environments can be simultaneously explained by a simple model of radiatively cooling gas. We show that most of such absorption line systems are consistent with being collisionally ionized, and estimate the maximum likelihood temperature of the gas in each observation. This model satisfactorily explains why O VI is regularly observed around star-forming low-z L* galaxies, and why N V is rarely seen around the same galaxies. We predict...

  16. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shenyang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Senor, David J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Setyawan, Wahyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Zhijie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-07-08

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the for- mation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was devel- oped. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn’t cause the gas bubble alignment, and fast 1-D migration of interstitials along $\\langle$110$\\rangle$ directions in the body-centered cubic U matrix causes the gas bubble alignment along $\\langle$110$\\rangle$ directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  17. The Formation and Distribution of the Marine Hydrocarbon Source Rock in the Tarim Basin, NW China

    Institute of Scientific and Technical Information of China (English)

    CAI Xiyuan; WANG Yi

    2008-01-01

    There are significant differences in type and distribution between marine source rock and continental source rock. According to the lithology, the Cambrian-Ordovician source rock in the Tarim basin is divided into two types: the carbonate source rock and the mud source rock. The two sets of source rocks are developed mainly in three sets of formations, Lower-Middle Cambrian carbonate source rock and mud source rock, Lower-Middle Ordovician mud source rock and Upper Ordovician lime mud source rock. The stratigraphic and areal distributions of the source rocks are controlled by the altitude and the sedimentary facies respectively. The mud source rock is developed in slope-semi deep sea environment. The source rock developed in the slope sedimentary environment is related with the anoxic environment and the one developed in semi deep sea has a close relationship with the up-flowing sea water. The carbonate source rock is developed mainly in platform slope of highstand systems tract and it is usually intimately associated with the salt rock. The Lower-Middle Cambrian carbonate source rock is developed mainly in the Bachu, Tazhong, Taugguzibasi and Yingmaili areas. The Lower-Middle Cambrian mud source rock is mainly developed in the areas east of the line of Kunan 1-Tadong 1. The Lower-Middle Ordovician mud source rock is developed mainly in the east slope of the Manjiaer depression. The carbonate source rock of Early Ordovician is developed mainly in the platform slope of highstand systems tract, such as the south margin of Tabei, the north slope of Tazhong, the Bachu area and Keping area.

  18. Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers.

    Science.gov (United States)

    Mayer, L; Kazantzidis, S; Escala, A; Callegari, S

    2010-08-26

    Observations of distant quasars indicate that supermassive black holes of billions of solar masses already existed less than a billion years after the Big Bang. Models in which the 'seeds' of such black holes form by the collapse of primordial metal-free stars cannot explain the rapid appearance of these supermassive black holes because gas accretion is not sufficiently efficient. Alternatively, these black holes may form by direct collapse of gas within isolated protogalaxies, but current models require idealized conditions, such as metal-free gas, to prevent cooling and star formation from consuming the gas reservoir. Here we report simulations showing that mergers between massive protogalaxies naturally produce the conditions for direct collapse into a supermassive black hole with no need to suppress cooling and star formation. Merger-driven gas inflows give rise to an unstable, massive nuclear gas disk of a few billion solar masses, which funnels more than 10(8) solar masses of gas to a sub-parsec-scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can subsequently grow to a billion solar masses on timescales of about 10(8) years by accreting gas from the surrounding disk.

  19. Effect of SO2 concentration on SOA formation in a photorreactor from a mixture of anthropogenic hydrocarbons and HONO

    Science.gov (United States)

    García Vivanco, Marta; Santiago, Manuel; García Diego, Cristina; Borrás, Esther; Ródenas, Milagros; Martínez-Tarifa, Adela

    2010-05-01

    Sulfur dioxide (SO2) is an important urban atmospheric pollutant, mainly produced by the combustion of fossil fuels containing sulfur. In the atmosphere, SO2 can react with OH radicals to form sulfuric acid, which can condense to form acidic aerosol. Sulfuric acid particles act as an acid catalyst for some heterogeneous carbonyl reactions like hydration, polymerization or acetals formation, which may lead to a large increase on SOA mass. In order to evaluate the effect of the SO2 concentration on SOA formation, 3 experiments were performed during the campaign carried out by CIEMAT on the EUPHORE facility (CEAM, Valencia, Spain) during June- July 2008. The objective of the campaign was to evaluate the effect of different experimental conditions on SOA formation from the photooxidation of some anthropogenic and biogenic VOCs using HONO as oxidant. Experiment on 6/17/08 was selected as base case (no SO2 was introduced) and experiments 6/26/08 and 7/1/08 were selected as high SO2 (2600 ug/m3) and low SO2 (60 ug/m3) concentration experiments respectively. In the three experiments a mixture of toluene, 1,3,5-TMB (trimethylbenzene), o-xylene and octane was selected as the parent VOCs. Single and coupled to mass spectroscopy gas cromatography (GC and GC/MS), as well as high performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR) were used to measure the initial VOCs and oxidant concentrations decay and the formation of gas phase oxidation products through the experiments. Aerosol size distribution and concentration were measured with SMPS (scanning mobility particle sizer) and TEOM (tapered element oscillating monitor) respectively. In addition, analysis of the organic and inorganic aerosol content was also performed via filter sampling followed by GC/MS and ionic chromatography (for organic and inrganic content respectively). Comparing the filters collected in the three experiments, clearly the largest mass aerosol formation is observed

  20. 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.

  1. 辽东湾地区锦州25-1大型轻质油气田成藏条件与成藏过程%Hydrocarbon accumulation conditions and process of Jinzhou 25-1 large-scale light gas-oil field in Liaodong Bay

    Institute of Scientific and Technical Information of China (English)

    田立新; 徐长贵; 江尚昆

    2011-01-01

    以三维地震资料、钻井资料分析以及流体包裹体资料为基础,分析锦州25-1大型轻质油气田基本成藏条件,并对其生烃史、排烃动力、成藏期次、油气充注过程进行研究.结果表明:锦州25-1油气田是一个优质的大型油气田,其形成的基本条件是该区具有多成因的大型圈闭群、充足的烃源岩条件以及理想的储盖组合;烃原岩排烃的主要动力是干酪根向油转化所产生的孔隙流体压力,孔隙流体压力的周期性累积和释放是油气幕式充注的主要原因;油气大规模充注成藏的时期是东营组末期(21~25 Ma);油气主要来自锦州25-1构造南北两翼的辽西北洼和辽西中洼;双灶供烃、超压-持续强充注、高效输导、理想储盖4因素耦合是研究区形成大型优质油气田的根本原因.%Based on 3D seismic data, drilling and fluid inclusion data, Jinzhou 25-1 large-scale oil-gas field formation conditions were analyzed. The hydrocarbon generation history, hydrocarbon expulsion dynamics, hydrocarbon accumulation period and hydrocarbon charging history of the field were researched. The results show that Jinzhou 2S-1 oil-gas field is a perfect large-scale light gas-oil field and its basic formation conditions include multiple genesis large-scale trap group, abundant hydrocarbon source rock and perfect reservoir-cap combination. The hydrocarbon expulsion dynamic in the source kitchen is the pore fluid pressure produced by the transformation from kerogen to hydrocarbon. The episodic accumulation and release of the pore fluid pressure is the main reason of the hydrocarbon episodic charging. The main pool forming period of the field is lateral period (21 -25 Ma) of Dongying group deposition. The hydrocarbon source of the oil-gas field is from the north sub-sags and middle sub-sag of Iiaoxi sag. The major reason of the large-scale gas-oil field formation in the area is the matching of the hydrocarbon supplying

  2. Gas6 downregulation impaired cytoplasmic maturation and pronuclear formation independent to the MPF activity.

    Directory of Open Access Journals (Sweden)

    Kyeoung-Hwa Kim

    Full Text Available Previously, we found that the growth arrest-specific gene 6 (Gas6 is more highly expressed in germinal vesicle (GV oocytes than in metaphase II (MII oocytes using annealing control primer (ACP-PCR technology. The current study was undertaken to investigate the role of Gas6 in oocyte maturation and fertilization using RNA interference (RNAi. Interestingly, despite the specific and marked decrease in Gas6 mRNA and protein expression in GVs after Gas6 RNAi, nuclear maturation including spindle structures and chromosome segregation was not affected. The only discernible effect induced by Gas6 RNAi was a change in maturation promoting factor (MPF activity. After parthenogenetic activation, Gas6 RNAi-treated oocytes at the MII stage had not developed further and arrested at MII (90.0%. After stimulation with Sr(2+, Gas6-silenced MII oocytes had markedly reduced Ca(2+ oscillation and exhibited no exocytosis of cortical granules. In these oocytes, sperm penetration occurred during fertilization but not pronucleus (PN formation. By roscovitine and colcemid treatment, we found that the Gas6 knockdown affected cytoplasmic maturation directly, independent to the changed MPF activity. These results strongly suggest that 1 the Gas6 signaling itself is important to the cytoplasmic maturation, but not nuclear maturation, and 2 the decreased Gas6 expression and decreased MPF activity separately or mutually influence sperm head decondensation and PN formation.

  3. Magnetic Collapse of a Neutron Gas No Magnetar Formation

    CERN Document Server

    Pérez-Martínez, A; Cuesta, H J M; Martinez, Aurora Perez; Rojas, Hugo Perez; Mosquera-Cuesta, Herman J.

    2000-01-01

    A degenerate neutron gas in equilibrium with a background of electrons and protons in a magnetic field exerts its pressure anisotropically, having a smaller value perpendicular than along the magnetic field. For critical fields the magnetic pressure may produce the vanishing of the equatorial pressure of the neutron gas, and the outcome could be a transverse collapse of the star. This fixes a limit to the fields to be observable in stable pulsars as a function of their density. The final structure left over after the implosion might be a mixed phase of nucleons and meson ($\\pi^{\\pm,0},\\kappa^{\\pm,0}$) condensate (a strange star also likely) or a black string, but no magnetar at all.

  4. Non-methane hydrocarbons (NMHCs) and their contribution to ozone formation potential in a petrochemical industrialized city, Northwest China

    Science.gov (United States)

    Jia, Chenhui; Mao, Xiaoxuan; Huang, Tao; Liang, Xiaoxue; Wang, Yanan; Shen, Yanjie; Jiang, Wanyanhan; Wang, Huiqin; Bai, Zhilin; Ma, Minquan; Yu, Zhousuo; Ma, Jianmin; Gao, Hong

    2016-03-01

    Hourly air concentrations of fifty-three non-methane hydrocarbons (NMHCs) were measured at downtown and suburb of Lanzhou, a petrochemical industrialized city, Northwest China in 2013. The measured data were used to investigate the seasonal characteristics of NMHCs air pollution and their contributions to the ozone formation in Lanzhou. Annually averaged NMHCs concentration was 38.29 ppbv in downtown Lanzhou. Among 53 NMHCs, alkanes, alkenes, and aromatics accounted for 57%, 23% and 20% of the total NMHCs air concentration, respectively. The atmospheric levels of toluene and propane with mean values of 4.62 and 4.56 ppbv were higher than other NMHCs, respectively. The ambient levels of NMHCs in downtown Lanzhou were compared with measured NMHCs data collected at a suburban site of Lanzhou, located near a large-scale petrochemical industry. Results show that the levels of alkanes, alkenes, and aromatics in downtown Lanzhou were lower by factors of 3-11 than that in west suburb of the city. O3-isopleth plots show that ozone was formed in VOCs control area in downtown Lanzhou and NOx control area at the west suburban site during the summertime. Propylene-equivalent (Prop-Equiv) concentration and the maximum incremental reactivity (MIR) in downtown Lanzhou indicate that cis-2-butene, propylene, and m/p-xylene were the first three compounds contributing to ozone formation potentials whereas in the petrochemical industrialized west suburb, ethane, propene, and trans-2-Butene played more important role in the summertime ozone formation. Principal component analysis (PCA) and multiple linear regression (MLR) were further applied to identify the dominant emission sources and examine their fractions in total NMHCs. Results suggest that vehicle emission, solvent usage, and industrial activities were major sources of NMHCs in the city, accounting for 58.34%, 22.19%, and 19.47% of the total monitored NMHCs in downtown Lanzhou, respectively. In the west suburb of the city

  5. Gas-oil fluids in the formation of travertines in the Baikal rift zone

    Science.gov (United States)

    Tatarinov, A. A.; Yalovik, L. I.; Shumilova, T. G.; Kanakin, S. V.

    2016-07-01

    Active participation of gas-oil fluids in the processes of mineral formation and petrogenesis in travertines of the Arshan and Garga hot springs is substantiated. The parageneses of the products of pyrolytic decomposition and oxidation of the gas-oil components of hydrothermal fluids (amorphous bitumen, graphite-like CM, and graphite) with different genetic groups of minerals crystallized in a wide range of P-T conditions were established. Travertines of the Baikal rift zone were formed from multicomponent hydrous-gas-oil fluids by the following basic mechanisms of mineral formation: chemogenic, biogenic, cavitation, fluid pyrometamorphism, and pyrolysis.

  6. 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.

  7. Preliminary formation analysis for compressed air energy storage in depleted natural gas reservoirs :

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, William Payton

    2013-06-01

    The purpose of this study is to develop an engineering and operational understanding of CAES performance for a depleted natural gas reservoir by evaluation of relative permeability effects of air, water and natural gas in depleted natural gas reservoirs as a reservoir is initially depleted, an air bubble is created, and as air is initially cycled. The composition of produced gases will be evaluated as the three phase flow of methane, nitrogen and brine are modeled. The effects of a methane gas phase on the relative permeability of air in a formation are investigated and the composition of the produced fluid, which consists primarily of the amount of natural gas in the produced air are determined. Simulations of compressed air energy storage (CAES) in depleted natural gas reservoirs were carried out to assess the effect of formation permeability on the design of a simple CAES system. The injection of N2 (as a proxy to air), and the extraction of the resulting gas mixture in a depleted natural gas reservoir were modeled using the TOUGH2 reservoir simulator with the EOS7c equation of state. The optimal borehole spacing was determined as a function of the formation scale intrinsic permeability. Natural gas reservoir results are similar to those for an aquifer. Borehole spacing is dependent upon the intrinsic permeability of the formation. Higher permeability allows increased injection and extraction rates which is equivalent to more power per borehole for a given screen length. The number of boreholes per 100 MW for a given intrinsic permeability in a depleted natural gas reservoir is essentially identical to that determined for a simple aquifer of identical properties. During bubble formation methane is displaced and a sharp N2methane boundary is formed with an almost pure N2 gas phase in the bubble near the borehole. During cycling mixing of methane and air occurs along the boundary as the air bubble boundary moves. The extracted gas mixture changes as a

  8. Petrophysical study of Szolnok Formation, Endrod gas field,

    Directory of Open Access Journals (Sweden)

    Abdel Moktader A. El Sayed

    2017-03-01

    Full Text Available Results of both porosity and permeability can be used by geologists, petrophysicists, and petroleum engineers to evaluate reservoir rock, heterogeneity, and pore space history through the time of deposition and lithifaction. On the other hand, reservoir quality as well as reservoir classification could be performed based on these data correlation. The Szolnok Formation is composed mainly of turbidity elastic deposits while siltstones are intercalated by sandstone beds and streaks of marls. In the present study, 213 core samples are obtained from the Szolnok Formation of the Great Hungarian plain, Hungary. Both horizontal and vertical permeability are measured. The Szolnok Formation has two main lithologic groups: 1. clean sandstone (141 samples and 2. siltstone – marl (72 samples, it can easily differentiate between good, intermediate or even bad reservoirs. Acoustic laboratory measurements have been carried out for only 30 sandstone rock samples parallel to the bedding plane (horizontal. This paper aims to evaluate some petrophysical relationships. On the other hand, both Wyllie and Raymer models were applied for porosity estimation from seismic velocity. It is worthy to mention that reservoir diagnosis of the Szolnok Formation was our target as well. Both the porosity and permeability variation range characterizing the detected lithologic facies of the Szolnok Formation are useful for reservoir zonation. The relationship between helium and mercury porosity for whole studied samples and sandstone samples as well, are supported by a high correlation coefficient and allow its application for prediction of porosity while it reduces costs and time of laboratory measurements. The evaluation of different calculated equations for porosity from compressional wave velocity data of the Szolnok Formation are studied and the relationship between velocity and porosity displays a clear inverse trend. The comparison between laboratory porosity and sonic

  9. Modeling gas formation and mineral precipitation in a granular iron column.

    Science.gov (United States)

    Jeen, Sung-Wook; Amos, Richard T; Blowes, David W

    2012-06-19

    In granular iron permeable reactive barriers (PRBs), hydrogen gas formation, entrapment and release of gas bubbles, and secondary mineral precipitation have been known to affect the permeability and reactivity. The multicomponent reactive transport model MIN3P was enhanced to couple gas formation and release, secondary mineral precipitation, and the effects of these processes on hydraulic properties and iron reactivity. The enhanced model was applied to a granular iron column, which was studied for the treatment of trichloroethene (TCE) in the presence of dissolved CaCO(3). The simulation reasonably reproduced trends in gas formation, secondary mineral precipitation, permeability changes, and reactivity changes observed over time. The simulation showed that the accumulation of secondary minerals reduced the reactivity of the granular iron over time, which in turn decreased the rate of mineral accumulation, and also resulted in a gradual decrease in gas formation over time. This study provides a quantitative assessment of the evolving nature of geochemistry and permeability, resulting from coupled processes of gas formation and mineral precipitation, which leads to a better understanding of the processes controlling the granular iron reactivity, and represents an improved method for incorporating these factors into the design of granular iron PRBs.

  10. Biodegradable particle formation for drug and gene delivery using supercritical fluid and dense gas.

    Science.gov (United States)

    Mishima, Kenji

    2008-02-14

    Recent developments in biodegradable particle formation using supercritical fluids and dense gases have been reviewed with an emphasis on studies of micronizing and encapsulating poorly-soluble pharmaceuticals and gene. General review articles published in previous years have then been provided. A brief description of the operating principles of some types of particle formation processes is given. These include the rapid expansion of supercritical solutions (RESS), the particles from gas-saturated solution (PGSS) processes, the gas antisolvent process (GAS), and the supercritical antisolvent process (SAS). The papers have been reviewed under two groups, one involving the production of particles from pure biodegradable substances, and the other involving coating, capsule, and impregnation that contain active components, especially those that relate to pharmaceuticals. This review is a comprehensive review specifically focused on the formation of biodegradable particles for drug and gene delivery system using supercritical fluid and dense gas.

  11. Intratumoral gas formation of HCC after trancatheter arterial chemoembolization(TACE)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jou Yeoun; Park, Byeong Ho; Nam, Kyung Jin; Auh, Jong Young; Lee, Yung Il [College of Medicine Dong-A University, Pusan (Korea, Republic of); Koo, Bong Sig [Bong Saeng Memorial Hospital, Pusan (Korea, Republic of)

    1995-06-15

    To determine the factors predisposing to the intratumoral gas formation after TACE in the treatment of HCC. A total of 176 pathologically or clinically proven patients with HCC on whom CT scan had been performed in 2 weeks to 3 months after TACE were reviewed. The patients were classified in two groups; intratumoral gas-forming group(n = 18) and non-gas forming group(n = 158). Chi-square (X{sup 2}) test was applied to analyze the factors influencing to gas formation. The radiological factors studied were the morphologic type and location of HCC, presence or absence of tumor capsule on CT, the degree of tumor vascularities, presence of absence of portal vein thrombosis, presence or absence of arterioportal shunt, and TACE catheterization method on angiographic examination and the duration of post-TAE fever. Intratumoral gas formation after TACE occurred significantly in tumors with peripheral location or capsule on CT tumors with less vascularity or peripheral arterioportal shunt on angiographic examination, and TACE with selective catheterization method({rho} < 0.05). But the morphologic types of HCC and presence of main portal vein thrombosis were not significantly different between the two groups({rho} > 0.05). The average duration of fever sustained after TACE was longer in gas-forming group than those in non-gas forming group ({rho} < 0.05). TACE of HCC with weak collaterals or with peripherd prevent recanalization from collaterals has tendency to intratumoral gas from-his and prolonged fever duration.

  12. 鄂尔多斯盆地富县—正宁地区延长组油气成藏期次%Classification of hydrocarbon accumulation phases of the Yanchang Formation in the Fuxian-Zhengning area, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    梁宇; 任战利; 史政; 赵筱燕; 于强; 吴晓青

    2011-01-01

    鄂尔多斯盆地富县—正宁地区延长组砂岩储层主要成岩作用有压实作用、胶结作用、溶蚀作用和裂隙作用,成岩自生矿物以绿泥石、自生石英和方解石为主.根据油气包裹体寄主成岩矿物的形成时间序列,识别出两期油气包裹体:第1期油气包裹体主要分布在石英、长石粒内愈合的、未切穿次生加大边的微裂隙及石英次生加大边内侧;第2期油气包裹体分布在晚期微裂隙和晚期亮晶方解石胶结物中.油气包裹体均一温度分布呈双峰型:早期峰值温度为110~120℃;晚期峰值温度为140~150℃.对油气包裹体均一温度、盐度、密度分析表明,研究区延长组油气为“一期两幕”成藏,且具有“边致密,边成藏”的特点.结合研究区延长组热演化史及储层伊利石K-Ar同位素定年结果研究表明,研究区主要油气成藏期为早白垩世(距今95~120Ma).%The main diagenesis of the Yanchang Formation sandstone reservoirs in the Fuxian-Zhengning area, Ordos Basin, includes compaction, cementation, corrosion and fracturation, and diagenetic authigenic minerals in these reservoirs are dominated by chlorite, authigenetic quartz and calcite. Two phases of hydrocarbon inclusions have been identified according to the time sequence of the formation of host diagenetic minerals, the earlier one composed of mostly brine inclusions that contain gaseous or liquid hydrocarbons either occurs along healed microfractures wrapped up by secondary growth edges of quartz or feldspar, or is trapped at the bottom of secondary growth edges of quartz or feldspar, while the later one mostly consisting of gas-liquid or liquid hydrocarbon inclusions occurs along the late-formed microfractures or in sparry calcite cements. Homogenization temperatures measured from brine inclusions associated with hydrocarbon ones show a bimodal distribution in the ranges with 110~120'C and 140~150'C as peak temperatures

  13. Shale gas reservoir characteristics of Ordovician-Silurian formations in the central Yangtze area, China

    Science.gov (United States)

    Shan, Chang'an; Zhang, Tingshan; Wei, Yong; Zhang, Zhao

    2016-07-01

    The characteristics of a shale gas reservoir and the potential of a shale gas resource of Ordovician-Silurian age in the north of the central Yangtze area were determined. Core samples from three wells in the study area were subjected to thin-section examination, scanning electron microscopy, nuclear magnetic resonance test