Formation of Particulate Matter from the Oxidation of Evaporated Wastewater from Hydraulic Fracturing Activity

Science.gov (United States)

Hildebrandt Ruiz, L.; Bean, J. K.; Bilotto, A.

2017-12-01

The use of hydraulic fracturing for production of petroleum and natural gas has increased dramatically in the last decade, but the environmental impacts of this technology remain unclear. Experiments were conducted to quantify airborne emissions from twelve samples of hydraulic fracturing flowback wastewater collected in the Permian Basin, as well as the photochemical processing of these emissions leading to the formation of particulate matter. The concentration of total volatile carbon (TVC, hydrocarbons evaporating at room temperature) averaged 29 milligrams of carbon per liter (mgC/L) and the TVC evaporation rate averaged 1357 mgC/L-m2-min. After photochemical oxidation under high NOx conditions the amount of organic particulate matter formed per milliliter of wastewater evaporated averaged 24 micrograms (µg); the amount of ammonium nitrate formed averaged 262 µg. In the state of Texas, the potential formation of PM from evaporated flowback wastewater is similar to the estimated PM emissions from diesel engines used in oil rigs, emphasizing the need to quantify wastewater evaporation and atmospheric processing of these emissions.

C2-C10 hydrocarbon emissions from a boreal wetland and forest floor

Directory of Open Access Journals (Sweden)

H. Hellén

2006-01-01

Full Text Available Emissions of various C2-C10 hydrocarbons (VOCs and halogenated hydrocarbons (VHOCs from a boreal wetland and a Scots pine forest floor in south-western Finland were measured by the static chamber technique. Isoprene was the main non-methane hydrocarbon emitted by the wetland, but small emissions of ethene, propane, propene, 1-butene, 2-methylpropene, butane, pentane and hexane were also detected. The isoprene emission from the wetland was observed to follow the commonly-used isoprene emission algorithm. The mean emission potential of isoprene was 224 µg m-2 h-1 for the whole season. This is lower than the emission potentials published earlier; that is probably at least partly due to the cold and cloudy weather during the measurements. No emissions were detected of monoterpenes or halogenated hydrocarbons from the wetland. The highest hydrocarbon emissions from the Scots pine forest floor were measured in spring and autumn. However, only a few measurements were conducted during summer. The main compounds emitted were monoterpenes. Isoprene emissions were negligible. The total monoterpene emission rates varied from zero to 373 µg m-2 h-1. The results indicated that decaying plant litter may be the source for these emissions. Small emissions of chloroform (100-800 ng m-2 h-1, ethene, propane, propene, 2-methylpropene, cis-2-butene, pentane, hexane and heptane were detected. Comparison with Scots pine emissions showed that the forest floor may be an important monoterpene source, especially in spring.

Characteristics of atmospheric non-methane hydrocarbons during haze episode in Beijing, China.

Science.gov (United States)

Guo, Songjun; Tan, Jihua; Duan, Jingchun; Ma, Yongliang; Yang, Fumo; He, Kebin; Hao, Jimin

2012-12-01

This study firstly focused on non-methane hydrocarbons (NMHCs) during three successive days with haze episode (16-18 August 2006) in Beijing. Concentrations of alkanes, alkenes, aromatic hydrocarbons, and ethyne all peaked at traffic rush hour, implying vehicular emission; and alkanes also peaked at non-traffic rush hour in the daytime, implying additional source. Especially, alkanes and aromatics clearly showed higher levels in the nighttime than that in the daytime, implying their active photochemical reactions in the daytime. Correlation coefficients (R (2)) showed that propane, n-butane, i-butane, ethene, propene, and benzene correlated with ethyne (R (2) = 0.61-0.66), suggesting that their main source is vehicular emission; 2-methylpentane and n-hexane correlated with i-pentane (R (2) = 0.61-0.64), suggesting that gasoline evaporation is their main source; and ethylbezene, m-/p-xylene, and o-xylene correlated with toluene (R (2) = 0.60-0.79), suggesting that their main source is similar to that of toluene (e.g., solvent usage). The R (2) of ethyne, i-pentane, and toluene with total NMHCs were 0.58, 0.76, and 0.60, respectively, indicating that ambient hydrocarbons are associated with vehicular emission, gasoline evaporation, and solvent usage. The sources of other hydrocarbons (e.g., ethane) might be natural gas leakage, biogenic emission, or long-range transport of air pollutants. Measured higher mean B/T ratio (0.78 ± 0.27) was caused by the more intensive photochemical activity of toluene than benzene, still indicating the dominant emission from vehicles.

Fate of sulfur mustard on soil: Evaporation, degradation, and vapor emission.

Science.gov (United States)

Jung, Hyunsook; Kah, Dongha; Chan Lim, Kyoung; Lee, Jin Young

2017-01-01

After application of sulfur mustard to the soil surface, its possible fate via evaporation, degradation following absorption, and vapor emission after decontamination was studied. We used a laboratory-sized wind tunnel, thermal desorber, gas chromatograph-mass spectrometry (GC-MS), and 13 C nuclear magnetic resonance ( 13 C NMR) for systematic analysis. When a drop of neat HD was deposited on the soil surface, it evaporated slowly while being absorbed immediately into the matrix. The initial evaporation or drying rates of the HD drop were found to be power-dependent on temperature and initial drop volume. Moreover, drops of neat HD, ranging in size from 1 to 6 μL, applied to soil, evaporated at different rates, with the smaller drops evaporating relatively quicker. HD absorbed into soil remained for a month, degrading eventually to nontoxic thiodiglycol via hydrolysis through the formation of sulfonium ions. Finally, a vapor emission test was performed for HD contaminant after a decontamination process, the results of which suggest potential risk from the release of trace chemical quantities of HD into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong.

Science.gov (United States)

Guo, H; Lee, S C; Louie, P K K; Ho, K F

2004-12-01

Ambient air quality measurements of 156 species including 39 alkanes, 32 alkenes, 2 alkynes, 24 aromatic hydrocarbons, 43 halocarbons and 16 carbonyls, were carried out for 120 air samples collected at two sampling stations (CW and TW) in 2001 throughout Hong Kong. Spatial variations of volatile organic compounds (VOCs) in the atmosphere were investigated. Levels of most alkanes and alkenes at TW site were higher than that at the CW site, while the BTEX concentrations at the two sites were close. The BTEX ratios at CW and TW were 1.6:10.1:1.0:1.6 and 2.1:10.8:1.0:2.0, respectively. For major halogenated hydrocarbons, the mean concentrations of chloromethane, CFCs 12 and 22 did not show spatial variations at the two sites. However, site-specific differences were observed for trichloroethene and tetrachloroethene. Furthermore, there were no significant differences for carbonyls such as formaldehyde, acetaldehyde and acetone between the two sites. The levels of selected hydrocarbons in winter were 1-5 times that in summer. There were no common seasonal trends for carbonyls in Hong Kong. The ambient level of formaldehyde, the most abundant carbonyl, was higher in summer. However, levels of acetaldehyde, acetone and benzaldehyde in winter were 1.6-3.8 times that in summer. The levels of CFCs 11 and 12, and chloromethane in summer were higher than that in winter. Strong correlation of most hydrocarbons with propene and n-butane suggested that the primary contributors of hydrocarbons were vehicular emissions in Hong Kong. In addition, gasoline evaporation, use of solvents, leakage of liquefied petroleum gas (LPG), natural gas leakage and other industrial emissions, and even biogenic emissions affected the ambient levels of hydrocarbons. The sources of halocarbons were mainly materials used in industrial processes and as solvents. Correlation analysis suggested that photochemical reactions made significant contributions to the ambient levels of carbonyls in summer whereas

A New Global Open Source Marine Hydrocarbon Emission Site Database

Science.gov (United States)

Onyia, E., Jr.; Wood, W. T.; Barnard, A.; Dada, T.; Qazzaz, M.; Lee, T. R.; Herrera, E.; Sager, W.

2017-12-01

Hydrocarbon emission sites (e.g. seeps) discharge large volumes of fluids and gases into the oceans that are not only important for biogeochemical budgets, but also support abundant chemosynthetic communities. Documenting the locations of modern emissions is a first step towards understanding and monitoring how they affect the global state of the seafloor and oceans. Currently, no global open source (i.e. non-proprietry) detailed maps of emissions sites are available. As a solution, we have created a database that is housed within an Excel spreadsheet and use the latest versions of Earthpoint and Google Earth for position coordinate conversions and data mapping, respectively. To date, approximately 1,000 data points have been collected from referenceable sources across the globe, and we are continualy expanding the dataset. Due to the variety of spatial extents encountered, to identify each site we used two different methods: 1) point (x, y, z) locations for individual sites and; 2) delineation of areas where sites are clustered. Certain well-known areas, such as the Gulf of Mexico and the Mediterranean Sea, have a greater abundance of information; whereas significantly less information is available in other regions due to the absence of emission sites, lack of data, or because the existing data is proprietary. Although the geographical extent of the data is currently restricted to regions where the most data is publicly available, as the database matures, we expect to have more complete coverage of the world's oceans. This database is an information resource that consolidates and organizes the existing literature on hydrocarbons released into the marine environment, thereby providing a comprehensive reference for future work. We expect that the availability of seafloor hydrocarbon emission maps will benefit scientific understanding of hydrocarbon rich areas as well as potentially aiding hydrocarbon exploration and environmental impact assessements.

Source apportionment vs. emission inventories of non-methane hydrocarbons (NMHC in an urban area of the Middle East: local and global perspectives

Directory of Open Access Journals (Sweden)

T. Salameh

2016-03-01

Full Text Available We applied the positive matrix factorization model to two large data sets collected during two intensive measurement campaigns (summer 2011 and winter 2012 at a sub-urban site in Beirut, Lebanon, in order to identify NMHC (non-methane hydrocarbons sources and quantify their contribution to ambient levels. Six factors were identified in winter and five factors in summer. PMF-resolved source profiles were consistent with source profiles established by near-field measurements. The major sources were traffic-related emissions (combustion and gasoline evaporation in winter and in summer accounting for 51 and 74 wt %, respectively, in agreement with the national emission inventory. The gasoline evaporation related to traffic source had a significant contribution regardless of the season (22 wt % in winter and 30 wt % in summer. The NMHC emissions from road transport are estimated from observations and PMF results, and compared to local and global emission inventories. The PMF analysis finds reasonable differences on emission rates, of 20–39 % higher than the national road transport inventory. However, global inventories (ACCMIP, EDGAR, MACCity underestimate the emissions up to a factor of 10 for the transportation sector. When combining emission inventory to our results, there is strong evidence that control measures in Lebanon should be targeted on mitigating the NMHC emissions from the traffic-related sources. From a global perspective, an assessment of VOC (volatile organic compounds anthropogenic emission inventories for the Middle East region as a whole seems necessary as these emissions could be much higher than expected at least from the road transport sector.

40 CFR 86.1217-96 - Evaporative emission enclosure calibrations.

Science.gov (United States)

2010-07-01

... procedure: (1) Carefully measure the internal length, width and height of the enclosure, accounting for... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Evaporative emission enclosure calibrations. 86.1217-96 Section 86.1217-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films

Science.gov (United States)

Sledge, Samiyyah M.; Khimji, Hussain; Borchman, Douglas; Oliver, Alexandria; Michael, Heidi; Dennis, Emily K.; Gerlach, Dylan; Bhola, Rahul; Stephen, Elsa

2016-01-01

Purpose The inhibition of the rate of evaporation (Revap) by surface lipids is relevant to reservoirs and dry eye. Our aim was to test the idea that lipid surface films inhibit Revap. Methods Revap were determined gravimetrically. Hydrocarbon chain conformation and structure were measured using a Raman microscope. Six 1-hydroxyl hydrocarbons (11–24 carbons in length) and human meibum were studied. Reflex tears were obtained from a 62-year-old male. Results The Raman scattering intensity of the lipid film deviated by about 7 % for hydroxyl lipids and varied by 21 % for meibum films across the entire film at a resolution of 5 µm2. All of the surface lipids were ordered. Revap of the shorter chain hydroxyl lipids were slightly (7%) but significantly lower compared with the longer chain hydroxyl lipids. Revap of both groups was essentially similar to that of buffer. A hydroxyl lipid film did not influence Revap over an estimated average thickness range of 0.69 to >6.9 µm. Revap of human tears and buffer with and without human meibum (34.4 µm thick) was not significantly different. Revap of human tears was not significantly different from buffer. Conclusions Human meibum and hydroxyl lipids, regardless of their fluidity, chain length, or thickness did not inhibit Revap of buffer or tears even though they completely covered the surface. It is unlikely that hydroxyl lipids can be used to inhibit Revap of reservoirs. Our data do not support the widely accepted (yet unconfirmed) idea that the tear film lipid layer inhibits Revap of tears. PMID:27395776

40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

Science.gov (United States)

2010-07-01

....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Oxides of nitrogen, carbon monoxide...

Estimation model for evaporative emissions from gasoline vehicles based on thermodynamics.

Science.gov (United States)

Hata, Hiroo; Yamada, Hiroyuki; Kokuryo, Kazuo; Okada, Megumi; Funakubo, Chikage; Tonokura, Kenichi

2018-03-15

In this study, we conducted seven-day diurnal breathing loss (DBL) tests on gasoline vehicles. We propose a model based on the theory of thermodynamics that can represent the experimental results of the current and previous studies. The experiments were performed using 14 physical parameters to determine the dependence of total emissions on temperature, fuel tank fill, and fuel vapor pressure. In most cases, total emissions after an apparent breakthrough were proportional to the difference between minimum and maximum environmental temperatures during the day, fuel tank empty space, and fuel vapor pressure. Volatile organic compounds (VOCs) were measured using a Gas Chromatography Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) to determine the Ozone Formation Potential (OFP) of after-breakthrough gas emitted to the atmosphere. Using the experimental results, we constructed a thermodynamic model for estimating the amount of evaporative emissions after a fully saturated canister breakthrough occurred, and a comparison between the thermodynamic model and previous models was made. Finally, the total annual evaporative emissions and OFP in Japan were determined and compared by each model. Copyright © 2017 Elsevier B.V. All rights reserved.

European type-approval test procedure for evaporative emissions from passenger cars against real-world mobility data from two Italian provinces.

Science.gov (United States)

Martini, Giorgio; Paffumi, Elena; De Gennaro, Michele; Mellios, Giorgos

2014-07-15

This paper presents an evaluation of the European type-approval test procedure for evaporative emissions from passenger cars based on real-world mobility data. The study relies on two large databases of driving patterns from conventional fuel vehicles collected by means of on-board GPS systems in the Italian provinces of Modena and Firenze. Approximately 28,000 vehicles were monitored, corresponding to approximately 36 million kilometres over a period of one month. The driving pattern of each vehicle was processed to derive the relation between trip length and parking duration, and the rate of occurrence of parking events against multiple evaporative cycles, defined on the basis of the type-approval test procedure as 12-hour diurnal time windows. These results are used as input for an emission simulation model, which calculates the total evaporative emissions given the characteristics of the evaporative emission control system of the vehicle and the ambient temperature conditions. The results suggest that the evaporative emission control system, fitted to the vehicles from Euro 3 step and optimised for the current type-approval test procedure, could not efficiently work under real-world conditions, resulting in evaporative emissions well above the type-approval limit, especially for small size vehicles and warm climate conditions. This calls for a revision of the type-approval test procedure in order to address real-world evaporative emissions. Copyright © 2014. Published by Elsevier B.V.

Prediction of cold start hydrocarbon emissions of air cooled two wheeler spark ignition engines by simple fuzzy logic simulation

Directory of Open Access Journals (Sweden)

Samuel Raja Ayyanan

2014-01-01

Full Text Available The cold start hydrocarbon emission from the increasing population of two wheelers in countries like India is one of the research issues to be addressed. This work describes the prediction of cold start hydrocarbon emissions from air cooled spark ignition engines through fuzzy logic technique. Hydrocarbon emissions were experimentally measured from test engines of different cubic capacity, at different lubricating oil temperature and at different idling speeds with and without secondary air supply in exhaust. The experimental data were used as input for modeling average hydrocarbon emissions for 180 seconds counted from cold start and warm start of gasoline bike engines. In fuzzy logic simulation, member functions were assigned for input variables (cubic capacity and idling rpm and output variables (average hydrocarbon emission for first 180 seconds at cold start and warm start. The knowledge based rules were adopted from the analyzed experimental data and separate simulations were carried out for predicting hydrocarbon emissions from engines equipped with and without secondary air supply. The simulation yielded the average hydrocarbon emissions of air cooled gasoline engine for a set of given input data with accuracy over 90%.

Evaporation characteristics of ETBE-blended gasoline

International Nuclear Information System (INIS)

Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

2015-01-01

Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

Evaporation characteristics of ETBE-blended gasoline

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Katsuhiro, E-mail: okamoto@nrips.go.jp [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan); Hiramatsu, Muneyuki [Yamanashi Prefectural Police H.Q., 312-4 Kubonakajima, Isawa-cho, Usui, Yamanashi 406-0036 (Japan); Hino, Tomonori; Otake, Takuma [Metropolitan Police Department, 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8929 (Japan); Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan)

2015-04-28

Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

The relationship between gasoline composition and vehicle hydrocarbon emissions: a review of current studies and future research needs.

Science.gov (United States)

Schuetzle, D; Siegl, W O; Jensen, T E; Dearth, M A; Kaiser, E W; Gorse, R; Kreucher, W; Kulik, E

1994-10-01

The purpose of this paper is to review current studies concerning the relationship of fuel composition to vehicle engine-out and tail-pipe emissions and to outline future research needed in this area. A number of recent combustion experiments and vehicle studies demonstrated that reformulated gasoline can reduce vehicle engine-out, tail-pipe, running-loss, and evaporative emissions. Some of these studies were extended to understand the fundamental relationships between fuel composition and emissions. To further establish these relationships, it was necessary to develop advanced analytical methods for the qualitative and quantitative analysis of hydrocarbons in fuels and vehicle emissions. The development of real-time techniques such as Fourier transform infrared spectroscopy, laser diode spectroscopy, and atmospheric pressure ionization mass spectrometry were useful in studying the transient behavior of exhaust emissions under various engine operating conditions. Laboratory studies using specific fuels and fuel blends were carried out using pulse flame combustors, single- and multicylinder engines, and vehicle fleets. Chemometric statistical methods were used to analyze the large volumes of emissions data generated from these studies. Models were developed that were able to accurately predict tail-pipe emissions from fuel chemical and physical compositional data. Some of the primary fuel precursors for benzene, 1,3-butadiene, formaldehyde, acetaldehyde and C2-C4 alkene emissions are described. These studies demonstrated that there is a strong relationship between gasoline composition and tail-pipe emissions.

EFFECT OF OXYGENATED HYDROCARBON ADDITIVES ON EXHAUST EMISSIONS OF A DIESEL ENGINE

OpenAIRE

C. Sundar Raj; S. Sendilvelan

2010-01-01

The use of oxygenated fuels seems to be a promising solution for reducing particulate emissions in existing and future diesel motor vehicles. In this work, the influence of the addition of oxygenated hydrocarbons to diesel fuels on performance and emission parameters of a diesel engine is experimentally studied. 3-Pentanone (C5H10O) and Methyl anon (C7H12O) were used as oxygenated fuel additives. It was found that the addition of oxygenated hydrocarbons reduced the production of soot precurs...

Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

African Journals Online (AJOL)

Prof. Ogunji

isolated fungi could be useful in the bioremediation of hydrocarbon polluted sites. Keywords: ... Technologies such as mechanical force, burying, evaporation, dispersant application, and ..... The effects of drilling fluids on marine bacteria from a.

Novel techniques for characterization of hydrocarbon emission sources in the Barnett Shale

Science.gov (United States)

Nathan, Brian Joseph

Changes in ambient atmospheric hydrocarbon concentrations can have both short-term and long-term effects on the atmosphere and on human health. Thus, accurate characterization of emissions sources is critically important. The recent boom in shale gas production has led to an increase in hydrocarbon emissions from associated processes, though the exact extent is uncertain. As an original quantification technique, a model airplane equipped with a specially-designed, open-path methane sensor was flown multiple times over a natural gas compressor station in the Barnett Shale in October 2013. A linear optimization was introduced to a standard Gaussian plume model in an effort to determine the most probable emission rate coming from the station. This is shown to be a suitable approach given an ideal source with a single, central plume. Separately, an analysis was performed to characterize the nonmethane hydrocarbons in the Barnett during the same period. Starting with ambient hourly concentration measurements of forty-six hydrocarbon species, Lagrangian air parcel trajectories were implemented in a meteorological model to extend the resolution of these measurements and achieve domain-fillings of the region for the period of interest. A self-organizing map (a type of unsupervised classification) was then utilized to reduce the dimensionality of the total multivariate set of grids into characteristic one-dimensional signatures. By also introducing a self-organizing map classification of the contemporary wind measurements, the spatial hydrocarbon characterizations are analyzed for periods with similar wind conditions. The accuracy of the classification is verified through assessment of observed spatial mixing ratio enhancements of key species, through site-comparisons with a related long-term study, and through a random forest analysis (an ensemble learning method of supervised classification) to determine the most important species for defining key classes. The hydrocarbon

Evaluating officially reported polycyclic aromatic hydrocarbon emissions in the Athabasca oil sands region with a multimedia fate model

Science.gov (United States)

Parajulee, Abha; Wania, Frank

2014-01-01

Emissions of organic substances with potential toxicity to humans and the environment are a major concern surrounding the rapid industrial development in the Athabasca oil sands region (AOSR). Although concentrations of polycyclic aromatic hydrocarbons (PAHs) in some environmental samples have been reported, a comprehensive picture of organic contaminant sources, pathways, and sinks within the AOSR has yet to be elucidated. We sought to use a dynamic multimedia environmental fate model to reconcile the emissions and residue levels reported for three representative PAHs in the AOSR. Data describing emissions to air compiled from two official sources result in simulated concentrations in air, soil, water, and foliage that tend to fall close to or below the minimum measured concentrations of phenanthrene, pyrene, and benzo(a)pyrene in the environment. Accounting for evaporative emissions (e.g., from tailings pond disposal) provides a more realistic representation of PAH distribution in the AOSR. Such indirect emissions to air were found to be a greater contributor of PAHs to the AOSR atmosphere relative to reported direct emissions to air. The indirect pathway transporting uncontrolled releases of PAHs to aquatic systems via the atmosphere may be as significant a contributor of PAHs to aquatic systems as other supply pathways. Emission density estimates for the three PAHs that account for tailings pond disposal are much closer to estimated global averages than estimates based on the available emissions datasets, which fall close to the global minima. Our results highlight the need for improved accounting of PAH emissions from oil sands operations, especially in light of continued expansion of these operations. PMID:24596429

Piston ring lubrication and hydrocarbon emissions from internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Froelund, K.

1997-11-01

Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model. This implies the development of a ring-pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally. Here again it would be of great interesting to look at the engine warm-up phase; The piston ring lubrication model should be adjusted for application together with the new hydrocarbon emission model for SI-engines at the Institute in order to increase the accuracy of the latter; The piston ring lubrication model could be used for describing the transport of PAH`s in diesel engines. (EG)

Towards Zero emissions. The challenge for hydrocarbons

International Nuclear Information System (INIS)

1999-01-01

The limited availability of natural resources, a still rapidly rising world population combined with overall economic growth will be stretching the Earth's carrying capacity beyond its limit, unless a suitable strategy is set in place. This scenario renders the concept of Zero Emissions all the more relevant, stressing as it does that the problem of environmental pollution cannot be effectively solved simply by reducing the production of wastes. In practical terms Zero Emissions can be conceived along similar lines to already establish corporate programs aiming to achieve zero accidents. Although no one claims that accidents are never going to occur, unless a clear objective is established, systems will not evolve in that direction. The target of Zero Emissions is therefore to move towards achieving the highest possible level of material productivity and energy efficiency. Considering how the hydrocarbon industry could become ever more engaged in applying the concept of Zero Emissions, and what in practice this means, can therefore play an important role in defining an appropriate innovation policy, and promoting long term corporate competitiveness

Measurements of atmospheric hydrocarbons and biogenic emission fluxes in the Amazon boundary layer

Science.gov (United States)

Zimmerman, P. R.; Greenberg, J. P.; Westberg, C. E.

1988-01-01

Tropospheric mixing ratios of methane, C2-C10 hydrocarbons, and carbon monoxide were measured over the Amazon tropical forest near Manaus, Amazonas, Brazil, in July and August 1985. The measurements, consisting mostly of altitude profiles of these gases, were all made within the atmospheric boundary layer up to an altitude of 1000 m above ground level. Data characterize the diurnal hydrocarbon composition of the boundary layer. Biogenic emissions of isoprene control hydroxyl radical concentrations over the forest. Biogenic emission fluxes of isoprene and terpenes are estimated to be 25,000 micrograms/sq m per day and 5600 micrograms/sq m per day, respectively. This isoprene emission is equivalent to 2 percent of the net primary productivity of the tropical forest. Atmospheric oxidation of biogenic isoprene and terpenes emissions from the Amazon forest may account for daily increases of 8-13 ppb for carbon monoxide in the planetary boundary layer.

EFFECT OF OXYGENATED HYDROCARBON ADDITIVES ON EXHAUST EMISSIONS OF A DIESEL ENGINE

Directory of Open Access Journals (Sweden)

C. Sundar Raj

2010-12-01

Full Text Available The use of oxygenated fuels seems to be a promising solution for reducing particulate emissions in existing and future diesel motor vehicles. In this work, the influence of the addition of oxygenated hydrocarbons to diesel fuels on performance and emission parameters of a diesel engine is experimentally studied. 3-Pentanone (C5H10O and Methyl anon (C7H12O were used as oxygenated fuel additives. It was found that the addition of oxygenated hydrocarbons reduced the production of soot precursors with respect to the availability of oxygen content in the fuel. On the other hand, a serious increase of NOx emissions is observed. For this reason the use of exhaust gas recirculation (EGR to control NOx emissions is examined. From the analysis of it is examined experimental findings, it is seen that the use of EGR causes a sharp reduction in NOx and smoke simultaneously. On the other hand, EGR results in a slight reduction of engine efficiency and maximum combustion pressure which in any case does not alter the benefits obtained from the oxygenated fuel.

HYDROCARBON EMISSION RINGS IN PROTOPLANETARY DISKS INDUCED BY DUST EVOLUTION

Energy Technology Data Exchange (ETDEWEB)

Bergin, Edwin A.; Du, Fujun; Schwarz, K.; Zhang, K. [Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109 (United States); Cleeves, L. Ilsedore [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Blake, G. A. [Division of Geological and Planetary Sciences, MC 150-21, California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125 (United States); Visser, R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748, Garching (Germany)

2016-11-01

We report observations of resolved C{sub 2}H emission rings within the gas-rich protoplanetary disks of TW Hya and DM Tau using the Atacama Large Millimeter Array. In each case the emission ring is found to arise at the edge of the observable disk of millimeter-sized grains (pebbles) traced by submillimeter-wave continuum emission. In addition, we detect a C{sub 3}H{sub 2} emission ring with an identical spatial distribution to C{sub 2}H in the TW Hya disk. This suggests that these are hydrocarbon rings (i.e., not limited to C{sub 2}H). Using a detailed thermo-chemical model we show that reproducing the emission from C{sub 2}H requires a strong UV field and C/O > 1 in the upper disk atmosphere and outer disk, beyond the edge of the pebble disk. This naturally arises in a disk where the ice-coated dust mass is spatially stratified due to the combined effects of coagulation, gravitational settling and drift. This stratification causes the disk surface and outer disk to have a greater permeability to UV photons. Furthermore the concentration of ices that transport key volatile carriers of oxygen and carbon in the midplane, along with photochemical erosion of CO, leads to an elemental C/O ratio that exceeds unity in the UV-dominated disk. Thus the motions of the grains, and not the gas, lead to a rich hydrocarbon chemistry in disk surface layers and in the outer disk midplane.

A comparison of the C{sub 2}-C{sub 9} hydrocarbon compositions of vehicle fuels and urban air in Dublin, Ireland

Energy Technology Data Exchange (ETDEWEB)

Broderick, B M; Marnane, I S [Trinity College, Dublin (Ireland). Dept. of Civil, Structural and Environmental Engineering

2002-07-01

Hourly roadside hydrocarbon concentrations were measured over a six-week period at a heavily trafficked junction in Dublin city centre. Samples of ten typical leaded and unleaded petrol fuels used in Irish vehicles were also collected and their hydrocarbon compositions determined. The measured ambient hydrocarbon concentrations are presented, as are the properties of each of the analysed fuels. Comparison of the ambient hydrocarbon concentrations and the fuel hydrocarbon composition reveals a strong correlation for most hydrocarbons, except those compounds that were wholly combustion derived (i.e. not present in the fuel). Different characteristics were noted for aromatics, alkanes and alkenes. The comparison of roadside ambient air and fuel hydrocarbon content agrees well with other studies that have compared fuel content and exhaust composition. The relative impacts of exhaust and evaporative emissions on roadside hydrocarbon concentrations are apparent. (Author)

Global atmospheric emissions of polycyclic aromatic hydrocarbons from 1960 to 2008 and future predictions

OpenAIRE

Shen, Huizhong; Huang, Ye; Wang, Rong; Zhu, Dan; Li, Wei; Shen, Guofeng; Wang, Bin; Zhang, Yanyan; Chen, Yuanchen; Lu, Yan; Chen, Han; Li, Tongchao; Sun, Kang; Li, Bengang; Liu, Wenxin

2013-01-01

Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimate country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1°× 0.1° grids based on a newly developed global high-resolution fuel combustion inven...

Method of treating emissions of a hybrid vehicle with a hydrocarbon absorber and a catalyst bypass system

Science.gov (United States)

Roos, Bryan Nathaniel; Gonze, Eugene V; Santoso, Halim G; Spohn, Brian L

2014-01-14

A method of treating emissions from an internal combustion engine of a hybrid vehicle includes directing a flow of air created by the internal combustion engine when the internal combustion engine is spinning but not being fueled through a hydrocarbon absorber to collect hydrocarbons within the flow of air. When the hydrocarbon absorber is full and unable to collect additional hydrocarbons, the flow of air is directed through an electrically heated catalyst to treat the flow of air and remove the hydrocarbons. When the hydrocarbon absorber is not full and able to collect additional hydrocarbons, the flow of air is directed through a bypass path that bypasses the electrically heated catalyst to conserve the thermal energy stored within the electrically heated catalyst.

Emission factors of particulate matter, polycyclic aromatic hydrocarbons, and levoglucosan from wood combustion in south-central Chile.

Science.gov (United States)

Jimenez, Jorge; Farias, Oscar; Quiroz, Roberto; Yañez, Jorge

2017-07-01

In south-central Chile, wood stoves have been identified as an important source of air pollution in populated areas. Eucalyptus (Eucalyptus globulus), Chilean oak (Nothofagus oblique), and mimosa (Acacia dealbata) were burned in a single-chamber slow-combustion wood stove at a controlled testing facility located at the University of Concepción, Chile. In each experiment, 2.7-3.1 kg of firewood were combusted while continuously monitoring temperature, exhaust gases, burn rate, and collecting particulate matter samples in Teflon filters under isokinetic conditions for polycyclic aromatic hydrocarbon and levoglucosan analyses. Mean particulate matter emission factors were 2.03, 4.06, and 3.84 g/kg dry wood for eucalyptus, oak, and mimosa, respectively. The emission factors were inversely correlated with combustion efficiency. The mean emission factors of the sums of 12 polycyclic aromatic hydrocarbons in particle phases were 1472.5, 2134.0, and 747.5 μg/kg for eucalyptus, oak, and mimosa, respectively. Fluoranthene, pyrene, benzo[a]anthracene, and chrysene were present in the particle phase in higher proportions compared with other polycyclic aromatic hydrocarbons that were analyzed. Mean levoglucosan emission factors were 854.9, 202.3, and 328.0 mg/kg for eucalyptus, oak, and mimosa, respectively. Since the emissions of particulate matter and other pollutants were inversely correlated with combustion efficiency, implementing more efficient technologies would help to reduce air pollutant emissions from wood combustion. Residential wood burning has been identified as a significant source of air pollution in populated areas. Local wood species are combusted for home cooking and heating, which releases several toxic air pollutants, including particulate matter, carbon monoxide, and polycyclic aromatic hydrocarbons. Air pollutant emissions depend on the type of wood and the technology and operational conditions of the wood stove. A better understanding of emissions from

Naphtha evaporation from oil sands tailings ponds

Energy Technology Data Exchange (ETDEWEB)

Kasperski, K.; Munoz, V.; Mikula, R. [Natural Resources Canada, Devon, AB (Canada). CANMET Western Research Centre

2010-07-01

The environmental impacts of volatile organic compounds (VOCs) from oil sands tailings ponds must be considered when evaluating new oil sands mining and extraction operations. Studies have suggested that only 40 percent of the solvent sent to tailings ponds is available to the environment, while the rest is irreversibly trapped. The recovery of hydrocarbons from oil sands froth process water is low. This PowerPoint presentation discussed a method of distinguishing between water and hydrocarbons at low temperatures. Samples were heated to 246 degrees C at 15 degrees C and held for 10 minutes. Heating was then resumed at 750 degrees C and held for 10 minutes in a pyrolysis phase, then cooled and reheated with an oxygen addition. The method demonstrated that the diluent distribution between the solids and water phases is misinterpreted as diluent that will evaporate, and diluent that will not evaporate. The study concluded by suggesting that the definition of recoverable and unrecoverable hydrocarbon should be re-termed as easily recoverable, and difficult to recover. tabs., figs.

Evaporative Gasoline Emissions and Asthma Symptoms

Science.gov (United States)

Gordian, Mary Ellen; Stewart, Alistair W; Morris, Stephen S

2010-01-01

Attached garages are known to be associated with indoor air volatile organic compounds (VOCs). This study looked at indoor exposure to VOCs presumably from evaporative emissions of gasoline. Alaskan gasoline contains 5% benzene making benzene a marker for gasoline exposure. A survey of randomly chosen houses with attached garages was done in Anchorage Alaska to determine the exposure and assess respiratory health. Householders were asked to complete a health survey for each person and a household survey. They monitored indoor air in their primary living space for benzene, toluene, ethylbenzene and xylenes for one week using passive organic vapor monitoring badges. Benzene levels in homes ranged from undetectable to 58 parts per billion. The median benzene level in 509 homes tested was 2.96 ppb. Elevated benzene levels in the home were strongly associated with small engines and gasoline stored in the garage. High concentrations of benzene in gasoline increase indoor air levels of benzene in residences with attached garages exposing people to benzene at levels above ATSDR’s minimal risk level. Residents reported more severe symptoms of asthma in the homes with high gasoline exposure (16%) where benzene levels exceeded the 9 ppb. PMID:20948946

Evaporation characteristics of ETBE-blended gasoline.

Science.gov (United States)

Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

2015-04-28

To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling of Heating and Evaporation of FACE I Gasoline Fuel and its Surrogates

KAUST Repository

Elwardani, Ahmed Elsaid

2016-04-05

The US Department of Energy has formulated different gasoline fuels called \\'\\'Fuels for Advanced Combustion Engines (FACE)\\'\\' to standardize their compositions. FACE I is a low octane number gasoline fuel with research octane number (RON) of approximately 70. The detailed hydrocarbon analysis (DHA) of FACE I shows that it contains 33 components. This large number of components cannot be handled in fuel spray simulation where thousands of droplets are directly injected in combustion chamber. These droplets are to be heated, broken-up, collided and evaporated simultaneously. Heating and evaporation of single droplet FACE I fuel was investigated. The heating and evaporation model accounts for the effects of finite thermal conductivity, finite liquid diffusivity and recirculation inside the droplet, referred to as the effective thermal conductivity/effective diffusivity (ETC/ED) model. The temporal variations of the liquid mass fractions of the droplet components were used to characterize the evaporation process. Components with similar evaporation characteristics were merged together. A representative component was initially chosen based on the highest initial mass fraction. Three 6 components surrogates, Surrogate 1-3, that match evaporation characteristics of FACE I have been formulated without keeping same mass fractions of different hydrocarbon types. Another two surrogates (Surrogate 4 and 5) were considered keeping same hydrocarbon type concentrations. A distillation based surrogate that matches measured distillation profile was proposed. The calculated molar mass, hydrogen-to-carbon (H/C) ratio and RON of Surrogate 4 and distillation based one are close to those of FACE I.

Emissions of hydrocarbons from marine phytoplankton—Some results from controlled laboratory experiments

Science.gov (United States)

McKay, W. A.; Turner, M. F.; Jones, B. M. R.; Halliwell, C. M.

Laboratory experiments have been carried out to help assess and quantify the role of marine phytoplankton in the production of non-methane hydrocarbons. Evidence is presented here that supports the hypothesis that some short-chain hydrocarbons are produced during diatom and dinoflagellate lifecycles. The pattern of their emissions to the air above axenic unicultures of diatoms and dinoflagellates has been followed. The results suggest that ethane, ethene, propane and propene are produced during the autolysis of some phytoplankton, possibly by the oxidation of polyunsaturated lipids released into their culture medium. In contrast, isoprene and hexane appear during phytoplankton growth and are thus most likely produced either directly by the plankton or through the oxidation of exuded dissolved organic carbon.

Biogenic nonmethane hydrocarbon emissions estimated from tethered balloon observations

Science.gov (United States)

Davis, K. J.; Lenschow, D. H.; Zimmerman, P. R.

1994-01-01

A new technique for estimating surface fluxes of trace gases, the mixed-layer gradient technique, is used to calculate isoprene and terpene emissions from forests. The technique is applied to tethered balloon measurements made over the Amazon forest and a pine-oak forest in Alabama at altitudes up to 300 m. The observations were made during the dry season Amazon Boundary Layer Experiment (ABLE 2A) and the Rural Oxidants in the Southern Environment 1990 experiment (ROSE I). Results from large eddy simulations of scalar transport in the clear convective boundary layer are used to infer fluxes from the balloon profiles. Profiles from the Amazon give a mean daytime emission of 3630 +/- 1400 micrograms isoprene sq m/h, where the uncertainty represents the standard deviation of the mean of eight flux estimates. Twenty profiles from Alabama give emissions of 4470 +/- 3300 micrograms isoprene sq m/h, 1740 +/- 1060 micrograms alpha-pinene sq m/h, and 790 +/- 560 micrograms beta-pinene sq m/h, respectively. These results are in agreement with emissions derived from chemical budgets. The emissions may be overestimated because of uncertainty about how to incorporate the effects of the canopy on the mixed-layer gradients. The large variability in these emission estimates is probably due to the relatively short sampling times of the balloon profiles, though spatially heterogeneous emissions may also play a role. Fluxes derived using this technique are representative of an upwind footprint of several kilometers and are independent of hydrocarbon oxidation rate and mean advection.

Gasoline reformulation to reduce exhaust emissions in Finnish conditions. Influence of sulphur and benzene contents of gasoline on exhaust emissions

International Nuclear Information System (INIS)

Kytoe, M.; Aakko, P.; Lappi, M.

1994-01-01

At earlier stages of the study it was found that the exhaust emissions from cars are reduced when using fuels with no more than 4 wt% of oxygen. At this stage of the study the work focused on impacts of the sulphur and benzene content of gasoline on exhaust emissions in Finland. Sulphur in gasoline retards the operation of the catalyst, and consequently the exhaust emissions of catalyst cars increase if the sulphur content of the fuel increases. In the present study, evaporation during refuelling were measured for fuels with varying vapour pressures and benzene contents of gasoline. The total hydrocarbon evaporation was reduced by 22 % (10 g) when the vapour pressure of gasoline was reduced from 85 kPa to 65 kPa. Correspondingly, benzene evaporation during refuelling was reduced to a third when the benzene content of the fuel was reduced from the level of 3 wt% to 1 wt%. The reduction of the sulphur content of gasoline from 500 ppm to 100 ppm affected regulated exhaust emissions from the catalyst car at +22 deg C as follows: CO emission was reduced on average by 14 % (0.175 g/km), CH emission by 7 % (0.010 g/km) and NO x emission by 9 % (0.011 g/km). At-7 deg C the percentual changes were smaller. When the benzene content of the fuel was reduced from 3 wt% to 1 wt%, the benzene emission from the catalyst cars was reduced by 20-30 % and from the non-catalyst cars on average by 30 % both at +22 deg C and -7 deg C. The benzene emission ranged 3-22 mg/km for the catalyst cars and 40-90 mg/km for the non-catalyst cars at +22 deg C in the FTP test

Comparative evaluation of GHG emissions from the use of Miscanthus for bio-hydrocarbon production via fast pyrolysis and bio-oil upgrading

International Nuclear Information System (INIS)

Shemfe, Mobolaji B.; Whittaker, Carly; Gu, Sai; Fidalgo, Beatriz

2016-01-01

Highlights: • GHG emissions from the upgrading of pyrolysis-derived bio-oil is quantified.. • Soil organic carbon sequestration rate had a significant effect on GHG emission. • Increasing plant scale could improve the environmental performance of the system. • Nitrogen to the pyrolysis reactor had significant impact on GHG emissions. - Abstract: This study examines the GHG emissions associated with producing bio-hydrocarbons via fast pyrolysis of Miscanthus. The feedstock is then upgraded to bio-oil products via hydroprocessing and zeolite cracking. Inventory data for this study were obtained from current commercial cultivation practices of Miscanthus in the UK and state-of-the-art process models developed in Aspen Plus®. The system boundary considered spans from the cultivation of Miscanthus to conversion of the pyrolysis-derived bio-oil into bio-hydrocarbons up to the refinery gate. The Miscanthus cultivation subsystem considers three scenarios for soil organic carbon (SOC) sequestration rates. These were assumed as follows: (i) excluding (SOC), (ii) low SOC and (iii) high (SOC) for best and worst cases. Overall, Miscanthus cultivation contributed moderate to negative values to GHG emissions, from analysis of excluding SOC to high SOC scenarios. Furthermore, the rate of SOC in the Miscanthus cultivation subsystem has significant effects on total GHG emissions. Where SOC is excluded, the fast pyrolysis subsystem shows the highest positive contribution to GHG emissions, while the credit for exported electricity was the main ‘negative’ GHG emission contributor for both upgrading pathways. Comparison between the bio-hydrocarbons produced from the two upgrading routes and fossil fuels indicates GHG emission savings between 68% and 87%. Sensitivity analysis reveals that bio-hydrocarbon yield and nitrogen gas feed to the fast pyrolysis reactor are the main parameters that influence the total GHG emissions for both pathways.

Changes in the Composition of Aromatherapeutic Citrus Oils during Evaporation

Directory of Open Access Journals (Sweden)

George W. Francis

2015-01-01

Full Text Available The composition of some commercial Citrus oils, lemon, sweet orange, and tangerine, designated for aromatherapy, was examined before and after partial evaporation in a stream of nitrogen. The intact oils contained the expected mixtures of mono- and sesquiterpenes, with hydrocarbons dominating and lesser amounts of oxygenated analogues making up the remainder. Gas chromatography-mass spectrometry was used to follow alterations in the relative amounts of the various components present as evaporation proceeded. Changes were marked, and in particular more volatile components present in the intact oils rapidly disappeared. Thus the balance of content was shifted away from monoterpene hydrocarbons towards the analogous alcohols and carbonyl compounds. The results of this differential evaporation are discussed and possible consequences for aromatherapy use are noted. The case of lemon oil was especially interesting as the relative amount of citral, a known sensitizer, remaining as time elapsed represented an increasing percentage of the total oil.

Infrared absorption and emission characteristics of interstellar PAHs [Polycyclic Aromatic Hydrocarbon

International Nuclear Information System (INIS)

Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

1986-01-01

The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm -1 (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs

Infrared absorption and emission characteristics of interstellar PAHs (Polycyclic Aromatic Hydrocarbon)

Energy Technology Data Exchange (ETDEWEB)

Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

1986-01-01

The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm/sup -1/ (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs.

The emissions of monoaromatic hydrocarbons from small polymeric toys placed in chocolate food products.

Science.gov (United States)

Marć, Mariusz; Formela, Krzysztof; Klein, Marek; Namieśnik, Jacek; Zabiegała, Bożena

2015-10-15

The article presents findings on the emissions of selected monoaromatic hydrocarbons from children's toys placed in chocolate food products. The emission test system involved the application of a new type of microscale stationary emission chamber, μ-CTE™ 250. In order to determine the type of the applied polymer in the manufacture of the tested toys, Fourier transform infrared spectroscopy and thermogravimetric analysis coupled with differential scanning calorimetry were used. It was found that the tested toy components or the whole toys (figurines) are made of two main types of polymers: polyamide and acrylonitrile-butadiene-styrene copolymer. Total number of studied small polymeric toys was 52. The average emissions of selected monoaromatic hydrocarbons from studied toys made of polyamide were as follows: benzene: 0.45 ± 0.33 ng/g; toluene: 3.3 ± 2.6 ng/g; ethylbenzene: 1.4 ± 1.4 ng/g; p,m-xylene: 2.5 ± 4.5 ng/g; and styrene: 8.2 ± 9.9 ng/g. In the case of studied toys made of acrylonitrile-butadiene-styrene copolymer the average emissions of benzene, toluene, ethylbeznene, p,m-xylene and styrene were: 0.31 ± 0.29 ng/g; 2.5 ± 1.4 ng/g; 4.6 ± 8.9 ng/g; 1.4 ± 1.1 ng/g; and 36 ± 44 ng/g, respectively. Copyright © 2015. Published by Elsevier B.V.

Data-driven analysis of the effectiveness of evaporative emissions control systems of passenger cars in real world use condition: Time and spatial mapping

Science.gov (United States)

De Gennaro, Michele; Paffumi, Elena; Martini, Giorgio

2016-03-01

This paper assesses the effectiveness of the evaporative emissions control systems of European passenger cars on the basis of real-world activity data. The study relies on two large datasets of driving patterns from conventional fuel vehicles collected by means of on-board GPS systems, consisting of 4.5 million trips and parking events recorded by monitoring 28,000 vehicles over one month. Real world evaporative emissions are estimated using a model that associates a carbon canister desorption event to each trip and a fuel vapour generation event to each parking. The mass of volatile organic compounds released into the air is calculated taking into account the hot-soak, permeation and breathing emission mechanisms. The analysis is based on 36 scenarios, defined by varying the climate conditions, the fuel vapour pressure, the tank material, the tank headspace volume, the purging volume flow rate and the mass of the activated carbon contained in the canister. The results show that in May 4 out of the 18 scenarios considered for Modena and 6 out of the 18 scenarios considered for Firenze lead to evaporative emissions values above the current type approval limit (i.e. 2 [g/day] per vehicle). In July, these numbers increase to 10 out of the 18 scenarios for Modena and to 12 out of the 18 scenarios for Firenze. Looking at the fleet distribution a share of approximately 20% of the fleet is characterised by evaporative emissions higher than the limit in May, increasing to 48% in July, with a peak value of 98%. The emission peak value is estimated to be approximately 4 [g/day] in May and 8 [g/day] in July, while the time-dependent results show emission rates up to nearly 15 [g/s] in Modena and 30 [g/s] in Firenze, with a respective cumulative value in July up to 0.4 and 0.8 tons of VOCs per day. The space-dependent results show a value of the emissions in July of approximately 4-to-8 [kg/km2/day] in the city areas. These results confirm previous findings from the authors

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment.

Science.gov (United States)

Mishra, Nitika; Ayoko, Godwin A; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis - Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Estimating net rainfall, evaporation and water storage of a bare soil from sequential L-band emissivities

Science.gov (United States)

Stroosnijder, L.; Lascano, R. J.; Newton, R. W.; Vanbavel, C. H. M.

1984-01-01

A general method to use a time series of L-band emissivities as an input to a hydrological model for continuously monitoring the net rainfall and evaporation as well as the water content over the entire soil profile is proposed. The model requires a sufficiently accurate and general relation between soil emissivity and surface moisture content. A model which requires the soil hydraulic properties as an additional input, but does not need any weather data was developed. The method is shown to be numerically consistent.

A Techno-Economic Analysis of Emission Controls on Hydrocarbon Biofuel Production

Energy Technology Data Exchange (ETDEWEB)

Bhatt, Arpit; Zhang, Yimin; Davis, Ryan; Eberle, Annika; Heath, Garvin

2016-06-23

Biofuels have the potential to reduce our dependency on petroleum-derived transportation fuels and decrease greenhouse gas (GHG) emissions. Although the overall GHG emissions from biofuels are expected to be lower when compared to those of petroleum fuels, the process of converting biomass feedstocks into biofuels emits various air pollutants, which may be subject to federal air quality regulation or emission limits. While prior research has evaluated the technical and economic feasibility of biofuel technologies, gaps still exist in understanding the regulatory issues associated with the biorefineries and their economic implications on biofuel production costs (referred to as minimum fuel selling price (MFSP) in this study). The aim of our research is to evaluate the economic impact of implementing emission reduction technologies at biorefineries and estimate the cost effectiveness of two primary control technologies that may be required for air permitting purposes. We analyze a lignocellulosic sugars-to-hydrocarbon biofuel production pathway developed by the National Renewable Energy Laboratory (NREL) and implement air emission controls in Aspen Plus to evaluate how they affect the MFSP. Results from this analysis can help inform decisions about biorefinery siting and sizing, as well as mitigate the risks associated with air permitting.

An Emission Inventory of Polycyclic Aromatic Hydrocarbons in China

Science.gov (United States)

Mu, Xilong; Zhu, Xianlei; Wang, Xuesong

2015-04-01

Polycyclic Aromatic Hydrocarbons (PAHs) are among the most dangerous compounds due to their high carcinogenic and mutagenic character. Emission inventory provides the primary data to account for the sources of ambient PAHs and server as a necessary database for effective PAHs pollution control. China is experiencing fast economic growth and large energy consumption, which might result in a large amount of PAHs anthropogenic emissions. Therefore, based on the previous studies and combined recently field emission measurements as well as socio-economic activity data, the development of a nationwide PAHs emission inventory is needed. In this work, the emission inventory of 16 PAHs listed as U.S. Environmental Protection Agency priority pollutants in China in the year 2012 is compiled. The emission amounts of PAHs were estimated as annual rates of emission-related activities multiplied by respective emission factors. The activities such as fuel consumption, including fossil fuel and biofuel, and socio-economic statistics were obtained from yearbook released by Chinese central government and/or provincial governments, as well as related industry reports. Emission factors were derived from the related literature. Recently reported emission factors from local measurements were used. The total emissions of PAHs were 120611 ton in 2012. In China, PAHs were emitted predominantly from domestic combustion of coal and biofuel, coking industry and motor vehicles, accounting for 72% of the total amount. PAHs emission profiles were significantly different between China and the other countries. The emission profile in China featured a relatively higher portion of high molecular weight species with carcinogenic potential due to large contributions of domestic combustion and coking industry. Domestic combustion of straw, coal and firewood emitted 19464 ton, 8831 ton, and 5062 ton of PAHs, respectively, which were much higher than those in other countries. Emission per capita showed

Motor vehicle fuel economy, the forgotten HC control stragegy. [Hydrocarbon (HC)

Energy Technology Data Exchange (ETDEWEB)

Deluchi, M.; Wang, Quanlu; Greene, D.L.

1992-06-01

Emissions of hydrocarbons from motor vehicles are recognized as major contributors to ozone pollution in urban areas. Petroleum-based motor fuels contain volatile organic compounds (VOC) which, together with oxides of nitrogen, promote the formation of ozone in the troposphere via complex photochemical reactions. VOC emissions from the tailpipe and evaporation from the fuel and engine systems of highway vehicles are believed to account for about 40% of total VOC emissions in any region. But motor fuels also generate emissions throughout the fuel cycle, from crude oil production to refining, storage, transportation, and handling, that can make significant contributions to the total inventory of VOC emissions. Many of these sources of emissions are directly related to the quantity of fuel produced and handled throughout the fuel cycle. It is, therefore, reasonable to expect that a reduction in total fuel throughput might result in a reduction of VOC emissions. In particular, reducing vehicle fuel consumption by increasing vehicle fuel economy should reduce total fuel throughput, thereby cutting total emissions of VOCS. In this report we identify the sources of VOC emissions throughout the motor fuel cycle, quantify them to the extent possible, and describe their dependence on automobile and light truck fuel economy.

Evaporation and stability of biodiesel and blends with diesel in ambient conditions

Energy Technology Data Exchange (ETDEWEB)

Yang, Zeyu; Hollebone, Bruce P.; Wang, Zhendi; Yang, Chun; Landriault, Mike [Emergencies Science and Technology Section, Environment Canada (Canada)], email: bruce.hollebone@ec.gc.ca

2011-07-01

This study investigates the weathering behavior of biodiesel fuels or fuel blends with diesel in ambient conditions. The goal of this study is to reveal the influencing factors on biodiesel storage stability, and weathering and evaporation rates. Samples of Fatty Acid Methyl Ester (FAME) based biodiesel compounds, ultra-low sulfur diesel blends, and petroleum diesels were prepared separately for testing. After weathering the samples for 190 days, a series of chemical procedures, including hydrocarbon extraction and gas chromatography, were conducted to reveal the aging process of the mixtures. Due to their high boiling points, biodiesel concentrations in FAME compounds generally demonstrated lower evaporation rates than petroleum diesels, which showed a fast and high mass loss. Moreover, it was shown that adding biodiesel components to fuel blends did not affect the evaporation of diesel hydrocarbon. In general, FAME compounds exhibited good storage stability under ambient weathering.

Pumping of hydrocarbons using non-evaporable getters

International Nuclear Information System (INIS)

Emerson, L.C.; Knize, R.J.; Cecchi, J.L.

1986-01-01

Pumping speed measurements have been obtained for a number of gaseous hydrocarbons including members of the alkene, alkadiene, and cycloalkane groups as a function of temperature using a Zr-Al alloy getter. Pumping speeds were obtained by analysis of an exponential least squares fit to the pressure decay curve following introduction of each gas. It was found that these pumping speeds are relatively high (up to 400 1/s) and exhibit, with only a few exceptions, little temperature dependence. This is in contrast to the earlier reported results for the alkane series

The Unusual Hydrocarbon Emission From the Early Carbon Star HD 100764: The Connection Between Aromatics and Aliphatics

National Research Council Canada - National Science Library

Sloan, G. C; Jura, M; Duley, W. W; Kraemer, K. E; Bernard-Salas, J; Forrest, W. J; Sargent, B; Li, A; Barry, D. J; Bohac, C. J

2007-01-01

.... The spectrum shows emission features from polycyclic aromatic hydrocarbons (PAHs) that are shifted to longer wavelengths than normally seen, a characteristic of "class C" systems in the classification scheme of Peeters et al...

Determination of the shapes and sizes of the regions in which in hadron-nucleus collisions reactions leading to the nucleon emission, particle production, and fragment evaporation occur

International Nuclear Information System (INIS)

Strugalski, Z.

1985-01-01

Shapes and sizes of the regions in target-nuclei in which reactions leading to the nucleon emission, particle production and fragment evaporation occur are determined. The region of nucleon emission is of cylindrical shape, with the diameter as large as two nucleon diameters, centered on the incident hadron course. The reactions leading to the particle production happen predominantly along the incident hadron course in nuclear matter. The fragment evaporation goes from the surface layer of the part of the target-nucleus damaged in nucleon emission process

Time trend of polycyclic aromatic hydrocarbon emission factors from motor vehicles

Science.gov (United States)

Tao, Shu; Shen, Huizhong; Wang, Rong; Sun, Kang

2010-05-01

Motor vehicle is an important emission source of polycyclic aromatic hydrocarbons (PAHs) and this is particularly true in urban areas. Motor vehicle emission factors (EFs) for individual PAH compound reported in the literature varied for 4 to 5 orders of magnitude, leading to high uncertainty in emission estimation. In this study, the major factors affecting EFs were investigated and characterized by regression models. Based on the model developed, a motor vehicle PAH emission inventory at country level was developed. It was found that country and model year are the most important factors affecting EFs for PAHs. The influence of the two factors can be quantified by a single parameter of per capita gross domestic production (purchasing power parity), which was used as the independent variables of the regression models. The models developed using randomly selected 80% of measurements and tested with the remained data accounted for 28 to 48% of the variations in EFs for PAHs measured in 16 countries over 50 years. The regression coefficients of the EF prediction models were molecular weight dependent. Motor vehicle emission of PAHs from individual countries in the world in 1985, 1995, 2005, 2015, and 2025 were calculated and the global emission of total PAHs were 470, 390, and 430 Gg in 1985, 1995, and 2005 and will be 290 and 130 Gg in 2015 and 2025, respectively. The emission is currently passing its peak and will decrease due to significant decrease in China and other developing countries.

Polycyclic Aromatic Hydrocarbon Emission Toward the Galactic Bulge

Science.gov (United States)

Shannon, M. J.; Peeters, E.; Cami, J.; Blommaert, J. A. D. L.

2018-03-01

We examine polycyclic aromatic hydrocarbon (PAH), dust, and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE, and NGC 6522. These fields are approximately centered on (l, b) = (0.°0, 1.°0), (0.°0, ‑1.°0), (0.°4, ‑2.°4), and (1.°0, ‑3.°8), respectively. Far-infrared photometric observations complement the Spitzer/IRS spectroscopic data and are used to construct spectral energy distributions. We find that the dust and PAH emission are exceptionally similar between C32 and C35 overall, in part explained due to their locations—they reside on or near boundaries of a 7 Myr old Galactic outflow event and are partly shock-heated. Within the C32 and C35 fields, we identify a region of elevated Hα emission that is coincident with elevated fine-structure and [O IV] line emission and weak PAH feature strengths. We are likely tracing a transition zone of the outflow into the nascent environment. PAH abundances in these fields are slightly depressed relative to typical ISM values. In the OGLE and NGC 6522 fields, we observe weak features on a continuum dominated by zodiacal dust. SED fitting indicates that thermal dust grains in C32 and C35 have temperatures comparable to those of diffuse, high-latitude cirrus clouds. Little variability is detected in the PAH properties between C32 and C35, indicating that a stable population of PAHs dominates the overall spectral appearance. In fact, their PAH features are exceptionally similar to that of the M82 superwind, emphasizing that we are probing a local Galactic wind environment.

Hydrocarbon emission fingerprints from contemporary vehicle/engine technologies with conventional and new fuels

Science.gov (United States)

Montero, Larisse; Duane, Matthew; Manfredi, Urbano; Astorga, Covadonga; Martini, Giorgio; Carriero, Massimo; Krasenbrink, Alois; Larsen, B. R.

2010-06-01

The present paper presents results from the analysis of 29 individual C 2-C 9 hydrocarbons (HCs) specified in the European Commission Ozone Directive. The 29 HCs are measured in exhaust from common, contemporary vehicle/engine/fuel technologies for which very little or no data is available in the literature. The obtained HC emission fingerprints are compared with fingerprints deriving from technologies that are being phased out in Europe. Based on the total of 138 emission tests, thirteen type-specific fingerprints are extracted (Mean ± SD percentage contributions from individual HCs to the total mass of the 29 HCs), essential for receptor modelling source apportionment. The different types represent exhaust from Euro3 and Euro4 light-duty (LD) diesel and petrol-vehicles, Euro3 heavy-duty (HD) diesel exhaust, and exhaust from 2-stroke preEuro, Euro1 and Euro2 mopeds. The fuels comprise liquefied petroleum gas, petrol/ethanol blends (0-85% ethanol), and mineral diesel in various blends (0-100%) with fatty acid methyl esters, rapeseed methyl esters palm oil methyl esters, soybean oil methyl or sunflower oil methyl esters. Type-specific tracer compounds (markers) are identified for the various vehicle/engine/fuel technologies. An important finding is an insignificant effect on the HC fingerprints of varying the test driving cycle, indicating that combining HC fingerprints from different emission studies for receptor modelling purposes would be a robust approach. The obtained results are discussed in the context of atmospheric ozone formation and health implications from emissions (mg km -1 for LD and mopeds and mg kW h -1 for HD, all normalised to fuel consumption: mg dm -3 fuel) of the harmful HCs, benzene and 1,3-butadiene. Another important finding is a strong linear correlation of the regulated "total" hydrocarbon emissions (tot-HC) with the ozone formation potential of the 29 HCs (ΣPO 3 = (1.66 ± 0.04) × tot-RH; r2 = 0.93). Tot-HC is routinely monitored in

An experimental study of the surface chemistry and evaporation kinetics of liquid sodium

International Nuclear Information System (INIS)

Becker, C.H.

1983-01-01

The evaporation rate and internal energy distribution of Na 2 evaporating from clean liquid Na and liquid Na exposed separately to O 2 and benzene were investigated by laser spectroscopy. The evaporating Na 2 was always found to be in thermal equilibrium with the surface. Oxygen increased the evaporation rate while benzene diminished it. A 3 keV Ar + beam was used to examine the surface by monitoring secondary ion emission. Ion emission from clean and oxygen exposed Na was extremely low; only limits could be established. Ion emission from sodium exposed to benzene could be observed only at lowered temperatures. The secondary ion emission, as well as visual observations of Na( 2 P-> 2 S) emission, are found to correspond to the evaporation rate behavior indicating that the Na surface remains very metal rich even while reacting with impinging oxygen at high (10 monolayers/s) rates. (orig.)

Emission factors of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from residential solid fuel combustions

Energy Technology Data Exchange (ETDEWEB)

Shen, Guofeng [Jiangsu Academy of Environmental Science, Nanjing (China). Inst. of Atmospheric Sciences

2014-07-01

Emission inventory is basic for the understanding of environmental behaviors and potential effects of compounds, however, current inventories are often associated with relatively high uncertainties. One important reason is the lack of emission factors, especially for the residential solid fuel combustion in developing countries. In the present study, emission factors of a group of pollutants including particulate matter, organic carbon, elemental carbon (sometimes known as black carbon) and polycyclic aromatic hydrocarbons were measured for a variety of residential solid fuels including coal, crop straw, wood, and biomass pellets in rural China. The study provided a large number of emission factors that can be further used in emission estimation. Composition profiles and isomer ratios were investigated and compared so as to be used in source apportionment. In addition, the present study identified and quantified the influence of factors like fuel moisture, volatile matter on emission performance.

Are biogenic emissions a significant source of summertime atmospheric toluene in the rural Northeastern United States?

Directory of Open Access Journals (Sweden)

M. L. White

2009-01-01

Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequently, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004–2006. These included: (1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet US EPA summertime volatility standards, (2 local industrial emissions and (3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d⁻¹, and did not fully account for the observed enhancements (20–50 pptv in 2004–2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d⁻¹ for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d⁻¹ and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

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

Hydrocarbons and air pollution

International Nuclear Information System (INIS)

Herz, O.

1992-01-01

This paper shows the influence of hydrocarbons vapors, emitted by transports or by volatile solvents using, on air pollution. Hydrocarbons are the principal precursors of photochemical pollution. After a brief introduction on atmospheric chemistry and photochemical reactions, the author describes the french prevention program against hydrocarbons emissions. In the last chapter, informations on international or european community programs for photochemical pollution study are given. 5 figs., 10 tabs

Decentralized production of hydrogen from hydrocarbons with reduced CO2 emission

International Nuclear Information System (INIS)

Nazim Muradov; Franklyn Smith; Cunping Huang; Ali T-Raissi

2006-01-01

Currently, most of the industrial hydrogen production is based on steam methane reforming process that releases significant amount of CO 2 into the atmosphere. CO 2 sequestration is one approach to solving the CO 2 emission problem for large centralized hydrogen plants, but it would be impractical for decentralized H 2 production units. The objective of this paper is to explore new routes to hydrogen production from natural gas without (or drastically reduced) CO 2 emissions. One approach analyzed in this paper is based on thermo-catalytic decomposition (TCD) of hydrocarbons (e.g., methane) to hydrogen gas and elemental carbon. The paper discusses some technological aspects of the TCD process development: (1) thermodynamic analysis of TCD using AspenPlus chemical process simulator, (2) heat input options to the endothermic process, (3) catalyst activity issues, etc. Production of hydrogen and carbon via TCD of methane was experimentally verified using carbon-based catalysts. (authors)

Technologies for hydrogen production based on direct contact of gaseous hydrocarbons and evaporated water with Molten Pb or Pb-Bi

International Nuclear Information System (INIS)

Gulevich, A. V.; Martynov, P. N.; Gulevsky, V. A.; Ulyanov, V. V.

2007-01-01

hydrogen (at t≥500 degree C). A valuable product is formed in this process - powdery carbon readily removable from the reaction zone owing to a large density difference of carbon vs. liquid metal. 3. The oxidation conversion of hydrocarbons (at t≥500 degree C). Hydrogen and CO 2 , hydrogen and synthetic gas (H 2 and CO mixture) can be obtained as end products. This process develops more effectively compared to the traditional vapor conversion. The increase of conversion effectiveness is caused by the new processes not employed before: hydrocarbon oxidation by oxides present in the reaction zone as dissolved in the melt and in solid phase; co-oxidation of hydrocarbons by evaporated water and HLMC oxides. As a result of enhanced effectiveness of oxidation conversion, the conditions for its fulfillment can be considerably simplified - the working pressure, as well as the process temperature can be decreased to the level at which it becomes possible to use structural materials, equipment, and appropriate measures for the employment of technology with coolants that have been developed and substantiated for operation in circuits with Pb and Pb-Bi coolants. The dimensions of 'direct contact' devices for hydrogen production can be very small. Therefore, they can find application both in large-scale hydrogen production, and in small-size (remote) sources of hydrogen

Systematics of evaporation

International Nuclear Information System (INIS)

Klots, C.E.

1991-01-01

Beginning with rather basic principles, general relations are obtained for evaporative rate constants. These are established both as a function of energy and of temperature. In parallel with this, expressions are developed for the kinetic energy distribution of the separating species. Explicit evaluation of the rate constants in the case of 'chemical' evaporation from an entity containing n monomeric units yields as a typical result k(T)(s -1 )=3.10 13 n 2/3 exp[6/n 1/3 ]exp(-ΔE a (n)/k B T). Experimental evidence in support of this relation is cited. Applications to thermionic emission are also noted. (orig.)

Worldwide overview of hydrocarbons and perspectives

International Nuclear Information System (INIS)

Tonnac, Alain de; Perves, Jean-Pierre

2013-12-01

This publication presents and comments data regarding the share of hydrocarbons in the world energy consumption, hydrocarbon trade flows, the new situation created by the emergence of shale hydrocarbons and the consequences for the world economy, and possible risks. The authors first comment the evolution of energy consumption and outline that the objectives of CO 2 and greenhouse gas emission will not be reached (these emissions increased in 2012 and in 2013). They indicate the emission situation in the USA and Japan, and notice that the objectives defined by the IEA are quite different from those defined by the EU. They analyse the evolutions by distinguishing different periods: 2005-2008 as a reference period, 2008-2012 as a period of change, and the current period as a period of flow inversion. Then, the authors propose two different scenarios of evolution of economic and energy policies. The evolution of hydrocarbon demand is commented, and the levels of reserves (oil, conventional gas, coal, nuclear fuels) are discussed. The market evolution is also discussed, not only from an economic point of view, but also in relationship with geopolitics. The authors notably outline that the energy price is different from one country to the other, discuss the issue of hydrocarbon refining, the role of CO 2 tax

New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes

International Nuclear Information System (INIS)

Chen, G. F.; Gong, M. Q.; Wu, J. F.; Zou, X.; Wang, S.

2014-01-01

Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment

International Nuclear Information System (INIS)

Mishra, Nitika; Ayoko, Godwin A.; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis – Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. - Highlights: • PAHs represent a major group of outdoor air pollutants. • Concentration levels of PAHS in urban schools ranged from 1.2 to 38 ng/m"3. • PCA–APCS technique used to identify sources of PAHs and their contributions. • Vehicular emissions (56%) were found to be the prominent sources of PAHs.

Inverse Opal Photonic Crystals as an Optofluidic Platform for Fast Analysis of Hydrocarbon Mixtures.

Science.gov (United States)

Xu, Qiwei; Mahpeykar, Seyed Milad; Burgess, Ian B; Wang, Xihua

2018-06-13

Most of the reported optofluidic devices analyze liquid by measuring its refractive index. Recently, the wettability of liquid on various substrates has also been used as a key sensing parameter in optofluidic sensors. However, the above-mentioned techniques face challenges in the analysis of the relative concentration of components in an alkane hydrocarbon mixture, as both refractive indices and wettabilities of alkane hydrocarbons are very close. Here, we propose to apply volatility of liquid as the key sensing parameter, correlate it to the optical property of liquid inside inverse opal photonic crystals, and construct powerful optofluidic sensors for alkane hydrocarbon identification and analysis. We have demonstrated that via evaporation of hydrocarbons inside the periodic structure of inverse opal photonic crystals and observation of their reflection spectra, an inverse opal film could be used as a fast-response optofluidic sensor to accurately differentiate pure hydrocarbon liquids and relative concentrations of their binary and ternary mixtures in tens of seconds. In these 3D photonic crystals, pure chemicals with different volatilities would have different evaporation rates and can be easily identified via the total drying time. For multicomponent mixtures, the same strategy is applied to determine the relative concentration of each component simply by measuring drying time under different temperatures. Using this optofluidic sensing platform, we have determined the relative concentrations of ternary hydrocarbon mixtures with the difference of only one carbon between alkane hydrocarbons, which is a big step toward detailed hydrocarbon analysis for practical use.

Investigation of the combustion kinetics and polycyclic aromatic hydrocarbon emissions from polycaprolactone combustion.

Science.gov (United States)

Chien, Y C; Yang, S H

2013-01-01

Polycaprolactone (PCL) is one of the most attractive biodegradable plastics that has been widely used in medicine and agriculture fields. Because of the large increase in biodegradable plastics usage, the production of waste biodegradable plastics will be increasing dramatically, producing a growing environmental problem. Generally, waste PCL is collected along with municipal solid wastes and then incinerated. This study investigates the combustion kinetics and emission factors of 16 US Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) in the PCL combustion. Experimentally, two reactions are involved in the PCL combustion process, possibly resulting in the emission of carbon dioxide, propanal, protonated caprolactone and very small amounts of PAH produced by incomplete combustion. The intermediate products may continuously be oxidized to form CO2. The emission factors for 16 US EPA priority PAHs are n.d. -2.95 microg/g, which are much lower than those of poly lactic acid and other plastics combustion. The conversion of PCL is 100%. Results from this work suggest that combustion is a good choice for the waste PCL disposal.

Detection of Polarized Infrared Emission by Polycyclic Aromatic Hydrocarbons in the MWC 1080 Nebula

International Nuclear Information System (INIS)

Zhang, Han; Telesco, Charles M.; Pantin, Eric; Barnes, Peter; Hoang, Thiem; Li, Aigen; Wright, Christopher M.; Li, Dan

2017-01-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrophysical environments, as revealed by their pronounced emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m commonly ascribed to the C–H and C–C vibrational modes. Although these features have long been predicted to be polarized, previous searches for PAH polarization led to null or, at best, tentative detections. Here we report the definite detection of polarized PAH emission at 11.3 μ m in the nebula associated with the Herbig Be star MWC 1080. We measure a polarization degree of 1.9% ± 0.2%, which is unexpectedly high compared to models. This poses a challenge in the current understanding of the alignment of PAHs, which is required to polarize the PAH emission but thought to be substantially suppressed. PAH alignment with a magnetic field via a resonance paramagnetic relaxation process may account for such a high level of polarization.

Detection of Polarized Infrared Emission by Polycyclic Aromatic Hydrocarbons in the MWC 1080 Nebula

Energy Technology Data Exchange (ETDEWEB)

Zhang, Han; Telesco, Charles M.; Pantin, Eric; Barnes, Peter [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Hoang, Thiem [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Li, Aigen [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Wright, Christopher M. [School of Physical, Environmental and Mathematical Sciences, UNSW Canberra, P.O. Box 7916, Canberra BC 2610 (Australia); Li, Dan, E-mail: hanzh0420@ufl.edu [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)

2017-07-20

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrophysical environments, as revealed by their pronounced emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m commonly ascribed to the C–H and C–C vibrational modes. Although these features have long been predicted to be polarized, previous searches for PAH polarization led to null or, at best, tentative detections. Here we report the definite detection of polarized PAH emission at 11.3 μ m in the nebula associated with the Herbig Be star MWC 1080. We measure a polarization degree of 1.9% ± 0.2%, which is unexpectedly high compared to models. This poses a challenge in the current understanding of the alignment of PAHs, which is required to polarize the PAH emission but thought to be substantially suppressed. PAH alignment with a magnetic field via a resonance paramagnetic relaxation process may account for such a high level of polarization.

Modeling unburned hydrocarbon formation due to absorption/desorption processes into the wall oil film

International Nuclear Information System (INIS)

Shih, L.K.; Assanis, D.N.

1992-01-01

This paper reports that as a result of continuing air pollution problems, very stringent regulations are being enforced to control emissions of unburned hydrocarbons (HC) from premixed-charge, spark-ignition engines. A number of attempts have been reported on modeling sources of HC emissions using various analytical tools. Over the past decade, the development of multi-dimensional reacting flow codes has advanced considerably. Perhaps the most widely used multi-dimensional engine simulation code is KIVA-II, which was developed at Lost Alamos National Laboratory. The ability to deal with moving boundary conditions caused by the piston movement is built in this code. This code also includes models for turbulent fluid flow, turbulent interaction between spray drops and gas, heat transfer, chemical reaction, and fuel spray. A standard k-ε turbulence model is used for gas flow. The fuel spray model is based on the stochastic particle technique, and includes sub-models for droplet injection, breakup, collision and coalescence, and evaporation

Quantification of variability and uncertainty in lawn and garden equipment NOx and total hydrocarbon emission factors.

Science.gov (United States)

Frey, H Christopher; Bammi, Sachin

2002-04-01

Variability refers to real differences in emissions among multiple emission sources at any given time or over time for any individual emission source. Variability in emissions can be attributed to variation in fuel or feedstock composition, ambient temperature, design, maintenance, or operation. Uncertainty refers to lack of knowledge regarding the true value of emissions. Sources of uncertainty include small sample sizes, bias or imprecision in measurements, nonrepresentativeness, or lack of data. Quantitative methods for characterizing both variability and uncertainty are demonstrated and applied to case studies of emission factors for lawn and garden (L&G) equipment engines. Variability was quantified using empirical and parametric distributions. Bootstrap simulation was used to characterize confidence intervals for the fitted distributions. The 95% confidence intervals for the mean grams per brake horsepower/hour (g/hp-hr) emission factors for two-stroke engine total hydrocarbon (THC) and NOx emissions were from -30 to +41% and from -45 to +75%, respectively. The confidence intervals for four-stroke engines were from -33 to +46% for THCs and from -27 to +35% for NOx. These quantitative measures of uncertainty convey information regarding the quality of the emission factors and serve as a basis for calculation of uncertainty in emission inventories (EIs).

Dismantling of Evaporators by Laser Cutting Measurement of Secondary Emissions

International Nuclear Information System (INIS)

Pilot, Guy; Fauvel, Sylvain; Gosse, Xavier; De Dinechin, Guillaume

2006-01-01

In order to dismantle the evaporators of an obsolete reprocessing plant in Marcoule, studies were carried out by IRSN (Institut de Radioprotection et de Surete Nucleaire) / DSU/SERAC in cooperation with CEA (power laser group) on the laser cutting of steel structures, on the request of COGEMA (now AREVA NC) /Marcoule (UP1 dismantling project manager) and CEA/UMODD (UP1 dismantling owner). The aim of these studies was: - to quantify and to characterize the secondary emissions produced by Nd-YAG laser cutting of Uranus 65 steel pieces representative of UP1 evaporator elements and to examine the influence of different parameters, - to qualify a pre-filtration technique and particularly an electrostatic precipitator, - to compare the Nd-YAG used with other cutting tools previously studied. The experiments, which took place in a 35 m 3 ventilated cutting cell, allow to underline the following points: for the Uranus 65 steel, the sedimented dross, the deposits on the walls of the cutting cell and the aerosols drawn in the ventilation exhaust duct (∼ 275 m 3 /h), represent respectively between 92% and 99%, between 0.01% and 0.25% and between 1% and 8% of the total collected mass, the attached slag varies much from one configuration to the other and can sometimes amount to a relatively important fraction of the total mass, the kerves vary from 2 mm up to 7 mm for the Uranus 65 steel plates (thickness: 13.8 mm for the single plate and 12.8 + 3.5 mm for the double plate), the exhausted aerosol mass per cut length (g/m) decreases with the cutting speed, varies neither with the stand-off nor with the gas pressure, is dependent upon the gas nature (for the double plate), increases with the laser power, is strongly affected by the nature of the steel (stainless steel or mild steel) and is independent upon the plate position, the size distribution of aerosols is multimodal with a main mode often around 0.45 μm, the electrostatic precipitator has been a satisfactory prefilter

Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons

Science.gov (United States)

Bauer, S. H.; Borchardt, D. B.

1990-07-01

We have extended the wavelength range of our previously constructed multichannel, fast recording spectrometer to the mid-infrared. With the initial configuration, using a silicon-diode (photovoltaic) array, we recorded light intensities simultaneously at 20 adjacent wavelengths, each with 20 μs time resolution. For studies in the infrared the silicon diodes are replaced by a 20 element PbSe (photoconducting) array of similar dimensions (1×4 mm/element), cooled by a three-stage thermoelectric device. These elements have useful sensitivities over 1.0-6.7 μm. Three interchangeable gratings in a 1/4 m monochromator cover the following spectral ranges: 1.0-2.5 μm (resolution 33.6 cm-1) 2.5-4.5 μm (16.8 cm-1) 4.0-6.5 μm (16.7 cm-1). Incorporated in the new housing there are individually controlled bias-power sources for each detector, two stages of analogue amplification and a 20-line parallel output to the previously constructed digitizer, and record/hold computer. The immediate application of this system is the study of emission and absorption spectra of shock heated hydrocarbons-C2H2, C4H4 and C6H6-which are possible precursors of species that generate infrared emissions in the interstellar medium. It has been recently proposed that these radiations are due to PAH that emit in the infrared upon relaxation from highly excited states. However, it is possible that such emissions could be due to shock-heated low molecular-weight hydrocarbons, which are known to be present in significant abundances, ejected into the interstellar medium during stellar outer atmospheric eruptions. The full Swan band system appeared in time-integrated emission spectra from shock heated C2H2 (1% in Ar; T5eq~=2500K) no soot was generated. At low resolution the profiles on the high frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no

New mechanism of cluster-field evaporation in rf breakdown

Directory of Open Access Journals (Sweden)

Z. Insepov

2004-12-01

Full Text Available Using a simple field evaporation model and molecular dynamics simulations of nanoscale copper tip evolution in a high electric field gradient typical for linacs, we have studied a new mechanism for rf-field evaporation. The mechanism consists of simultaneous (collective field evaporation of a large group of tip atoms in high-gradient fields. Thus, evaporation of large clusters is energetically more favorable when compared with the conventional, “one-by-one” mechanism. The studied mechanism could also be considered a new mechanism for the triggering of rf-vacuum breakdown. This paper discusses the mechanism and the experimental data available for electric field evaporation of field-emission microscopy tips.

The influence of droplet evaporation on fuel-air mixing rate in a burner

Science.gov (United States)

Komiyama, K.; Flagan, R. C.; Heywood, J. B.

1977-01-01

Experiments involving combustion of a variety of hydrocarbon fuels in a simple atmospheric pressure burner were used to evaluate the role of droplet evaporation in the fuel/air mixing process in liquid fuel spray flames. Both air-assist atomization and pressure atomization processes were studied; fuel/air mixing rates were determined on the basis of cross-section average oxygen concentrations for stoichiometric overall operation. In general, it is concluded that droplets act as point sources of fuel vapor until evaporation, when the fuel jet length scale may become important in determining nonuniformities of the fuel vapor concentration. In addition, air-assist atomizers are found to have short droplet evaporation times with respect to the duration of the fuel/air mixing process, while for the pressure jet atomizer the characteristic evaporation and mixing times are similar.

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...

Emission of Polycyclic Aromatic Hydrocarbons from the Exhalation Zones of Thermally Active Mine Waste Dumps

Directory of Open Access Journals (Sweden)

Patrycja Kuna-Gwoździewicz

2013-01-01

Full Text Available The article presents results of research carried out on the occurrence of polycyclic aromatic hydrocarbons (PAH in gases of exhalation zones, created on the surface of a thermally active coal mine waste dump. The oxidation and self-heating of mine waste are accompanied with the intensive emission of flue gases, including PAH group compounds. Taking into consideration the fact the hydrocarbons show strong genotoxic, mutagenic and carcinogenic properties, research was conducted to establish their content in the examined gases. The research object was a gangue dump located in Rybnik. The research was performed in 2012. In total, 24 samples of gas were collected with PUF (polyurethane foam sampling cartridges with a quartz fibre filter and an aspirator. The collected samples were analysed with the use of high performance liquid chromatography (HPLC and a fluorescence detector (FLD to evaluate the amount of PAH present.

Emission factors of polycyclic and nitro-polycyclic aromatic hydrocarbons from residential combustion of coal and crop residue pellets.

Science.gov (United States)

Yang, Xiaoyang; Liu, Shijie; Xu, Yisheng; Liu, Yu; Chen, Lijiang; Tang, Ning; Hayakawa, Kazuichi

2017-12-01

Polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) are toxic pollutants mainly produced during fossil fuel combustion. Domestic coal stoves, which emit large amounts of PAHs and NPAHs, are widely used in the Chinese countryside. In this study, emission factors (Efs) for 13 PAH species and 21 NPAH species for four raw coal (three bituminous and one anthracite), one honeycomb briquette, and one crop residue pellet (peanut hulls) samples burned in a typical Chinese rural cooking stove were determined experimentally. The PAH and NPAH Efs for the six fuels were 3.15-49 mg/kg and 0.32-100 μg/kg, respectively. Peanut hulls had very high Efs for both PAHs and NPAHs, and honeycomb briquettes had the lowest Efs. 2-Nitropyrene and 2-nitrofluoranthene, which are NPAHs typically found in secondary organic aerosol, were detected in the emissions from some fuels, suggesting that chemical reactions may have occurred in the dilution tunnel between the flue gas leaving the stove and entering the sampler. The 1-nitropyrene to pyrene diagnostic ratios for coal and peanut hulls were 0.0001 ± 0.0001 and 0.0005, respectively. These were in the same order of magnitude as reference ratios for emissions during coal combustion. The 6-nitrobenzo[a]pyrene to benzo[a]pyrene ratios for the fuels were determined, and the ratios for coal and peanut hulls were 0.0010 ± 0.0001 and 0.0014, respectively. The calculated potential toxic risks indicated that peanut hull emissions were very toxic, especially in terms of NPAHs, compared with emissions from the other fuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance estimation of ejector cycles using heavier hydrocarbon refrigerants

International Nuclear Information System (INIS)

Kasperski, Jacek; Gil, Bartosz

2014-01-01

Computer software basing on theoretical model of Huang et al. with thermodynamic properties of hydrocarbons was prepared. Investigation was focused on nine hydrocarbons: propane, butane, iso-butane, pentane, iso-pentane, hexane, heptane and octane. A series of calculations was carried out for the generator temperature between 70 and 200 °C, with assumed temperatures of evaporation 10 °C and condensation 40 °C. Calculation results show that none of the hydrocarbons enables high efficiency of a cycle in a wide range of temperature. Each hydrocarbon has its own maximal entrainment ratio at its individual temperature of optimum. Temperatures of entrainment ratios optimum increase according to the hydrocarbon heaviness with simultaneous increase of entrainment ratio peak values. Peak values of the COP do not increase according to the hydrocarbons heaviness. The highest COP = 0.32 is achieved for iso-butane at 102 °C and the COP = 0.28 for pentane at 165 °C. Heptane and octane can be ignored. - Highlights: • Advantages of use of higher hydrocarbons as ejector refrigerants were presumed. • Computer software basing on theoretical model of Huang et al. (1999) was prepared. • Optimal temperature range of vapor generation for each hydrocarbon was calculated

Climate change and the hydrocarbon industry; A klimavaltozas es a szenhidrogenipar

Energy Technology Data Exchange (ETDEWEB)

Almasi, M.; Racz, L.

1999-07-01

The theory of the greenhouse effect and the impact of greenhouse phenomena on climate change are summarized. Theoretical bases of climate changes are outlined and the relationship between greenhouse effects and hydrocarbon production is analyzed. Hungary's carbon dioxide emissions as well as the possibilities of reducing the emissions caused by hydrocarbons are discussed. Finally the tasks of the Hungarian hydrocarbon industry in relation to the environmental problems are concerned.

Correlation of chemical evaporation rate with vapor pressure.

Science.gov (United States)

Mackay, Donald; van Wesenbeeck, Ian

2014-09-02

A new one-parameter correlation is developed for the evaporation rate (ER) of chemicals as a function of molar mass (M) and vapor pressure (P) that is simpler than existing correlations. It applies only to liquid surfaces that are unaffected by the underlying solid substrate as occurs in the standard ASTM evaporation rate test and to quiescent liquid pools. The relationship has a sounder theoretical basis than previous correlations because ER is correctly correlated with PM rather than P alone. The inclusion of M increases the slope of previous log ER versus log P regressions to a value close to 1.0 and yields a simpler one-parameter correlation, namely, ER (μg m(-1) h(-1)) = 1464P (Pa) × M (g mol(-1)). Applications are discussed for the screening level assessment and ranking of chemicals for evaporation rate, such as pesticides, fumigants, and hydrocarbon carrier fluids used in pesticide formulations, liquid consumer products used indoors, and accidental spills of liquids. The mechanistic significance of the single parameter as a mass-transfer coefficient or velocity is discussed.

Physical organogels: mechanism and kinetics of evaporation of the solvents entrapped within network scaffolding

International Nuclear Information System (INIS)

Markovic, Nov; Dutta, Naba K.

2005-01-01

A series of hydrocarbon gels (based on leaded petrol and decalin) using physically crosslinked networks have been prepared using Al-salt of fatty acid as the physical gelling agent. The effects of gel network scaffolding on the mechanism and kinetics of evaporation of the solvents from the gels were investigated using conventional, isothermal and modulated thermogravimetric analysis. It has been clearly observed that the evaporation of solvent from gels followed a complex evaporation pattern compared to the pure solvent. It appears that with increase in network scaffolding the maximum rate of evaporation of the solvent decreases and its distribution become broader. The activation energy of evaporation for these solvents was found not to be dramatically dependent on the concentration of the gelator and tightness of the network scaffolding. Amongst different methods employed, isothermal measurements provided reliable information about the mechanism of evaporation. Modulated thermogravimetric analysis proved to be an efficient method to achieve kinetic parameters of evaporation from a single dynamic experiment. Scanning electron microscopy was used to probe for both dry gelator and gel network after evaporation of the solvents for evaluation of their surface morphology

Top-down constraints on methane and non-methane hydrocarbon emissions in the US Four Corners

Science.gov (United States)

Petron, G.; Miller, B. R.; Vaughn, B. H.; Kofler, J.; Mielke-Maday, I.; Sherwood, O.; Schwietzke, S.; Conley, S.; Sweeney, C.; Dlugokencky, E. J.; White, A. B.; Tans, P. P.; Schnell, R. C.

2017-12-01

A NASA and NOAA supported field campaign took place in the US Four Corners in April 2015 to further investigate a regional "methane hotspot" detected from space. The Four Corners region is home to the fossil fuel rich San Juan Basin, which extends between SE Colorado and NE New Mexico. The area has been extracting coal, oil and natural gas for decades. Degassing from the Fruitland coal outcrop on the Colorado side has also been reported. Instrumented aircraft, vans and ground based wind profilers were deployed for the campaign with the goal to quantify and attribute methane and non-methane hydrocarbon emissions in the region. A new comprehensive analysis of the campaign data sets will be presented and top-down emission estimates for methane and ozone precursors will be compared with available bottom-up estimates.

Organic emission calculations for the 242-A evaporator vessel vent system

International Nuclear Information System (INIS)

Bowman, M.R.

1996-01-01

This document contains historical calculations originally published in the 242-A Evaporator Dangerous Waste Permit Application, DOE/RL-90-42, Rev 0. They are being released as a supporting document, along with brief explanatory information, to be used as a reference in Rev 1 of the permit application and in other supporting documents, such as the 242-A Evaporator Data Quality Objectives

Identification of emission sources of particle-bound polycyclic aromatic hydrocarbons in the vicinity of the industrial zone of the city of Novi Sad

OpenAIRE

Jovčić Nataša S.; Radonić Jelena R.; Turk-Sekulić Maja M.; Vojinović-Miloradov Mirjana B.; Popov Srđan B.

2013-01-01

Data on polycyclic aromatic hydrocarbons (PAHs) in ambient air accessed at selected locations in the vicinity of the industrial zone of the city of Novi Sad, Serbia, have been presented and analyzed in order to determine seasonal and spatial variations and to identify emission sources of particle-bound PAHs. Previous studies have demonstrated that the major contributors of PAHs in urban areas are the emissions from vehicle exhaust, and emissions releases from industrial processes like a...

Artificial weathering of oils by rotary evaporator

International Nuclear Information System (INIS)

Fieldhouse, B.; Hollebone, B.P.; Singh, N.R.; Tong, T.S.; Mullin, J.

2009-01-01

Oil weathering has a considerable affect on the behaviour, impact and ultimate fate of an oil spill. As such, efforts have been made to study weathering as a whole using bench-scale procedures. The studies are generally divided into individual processes where the effect of other major processes are introduce as an amended sample input rather than a concurrent process. The weathering process that has the greatest effect immediately following an oil spill is evaporation, particularly for lighter oils. The rotary evaporator apparatus offers a convenient means of producing artificially weathered oil for laboratory studies. This paper reported on a study that examined the representativeness of samples obtained by this method compared to pan evaporation and the impact of changes to the apparatus or method parameters on sample chemistry. Experiments were performed on Alberta Sweet Mixed Blend no. 5 in a rotary evaporator under varying conditions of temperature and air flow at ambient pressure using 2 apparatus. The rate of mass loss increased with temperature and air flow rate as expected, but the quantitative relationships could not be defined from the data due to contributions by other uncontrolled factors. It was concluded that the rotary evaporator is not suited for evaporation rate studies, but rather for producing samples suitable for use in other studies. Chemical analysis showed that the relative abundance distributions of target n-alkane hydrocarbons varied with the degree of weathering of an oil in a consistent manner at ambient pressure, regardless of the temperature, rate of air exchange or other factors related to the apparatus and procedure. The composition of the artificially weathered oil was also consistent with that from an open pan simulation of a weathered oil slick. Loss of water content varied with the conditions of evaporation because of the differential rates of evaporation due to relative humidity considerations. It was concluded that weathering

Ambient air emissions of polycyclic aromatic hydrocarbons and female breast cancer incidence in US.

Science.gov (United States)

Stults, William Parker; Wei, Yudan

2018-05-05

To examine ambient air pollutants, specifically polycyclic aromatic hydrocarbons (PAHs), as a factor in the geographic variation of breast cancer incidence seen in the US, we conducted an ecological study involving counties throughout the US to examine breast cancer incidence in relation to PAH emissions in ambient air. Age-adjusted incidence rates of female breast cancer from the surveillance, epidemiology, and end results (SEER) program of the US National Cancer Institute were collected and analyzed using SEER*Stat 8.3.2. PAH emissions data were obtained from the Environmental Protection Agency. Linear regression analysis was performed using SPSS 23 software for Windows to analyze the association between PAH emissions and breast cancer incidence, adjusting for potential confounders. Age-adjusted incidence rates of female breast cancer were found being significantly higher in more industrialized metropolitan SEER regions over the years of 1973-2013 as compared to less industrialized regions. After adjusting for sex, race, education, socioeconomic status, obesity, and smoking prevalence, PAH emission density was found to be significantly associated with female breast cancer incidence, with the adjusted β of 0.424 (95% CI 0.278, 0.570; p < 0.0001) for emissions from all sources and of 0.552 (95% CI 0.278, 0.826; p < 0.0001) for emissions from traffic source. This study suggests that PAH exposure from ambient air could play a role in the increased breast cancer risk among women living in urban areas of the US. Further research could provide insight into breast cancer etiology and prevention.

Sensitivity of modeled ozone concentrations to uncertainties in biogenic emissions

International Nuclear Information System (INIS)

Roselle, S.J.

1992-06-01

The study examines the sensitivity of regional ozone (O3) modeling to uncertainties in biogenic emissions estimates. The United States Environmental Protection Agency's (EPA) Regional Oxidant Model (ROM) was used to simulate the photochemistry of the northeastern United States for the period July 2-17, 1988. An operational model evaluation showed that ROM had a tendency to underpredict O3 when observed concentrations were above 70-80 ppb and to overpredict O3 when observed values were below this level. On average, the model underpredicted daily maximum O3 by 14 ppb. Spatial patterns of O3, however, were reproduced favorably by the model. Several simulations were performed to analyze the effects of uncertainties in biogenic emissions on predicted O3 and to study the effectiveness of two strategies of controlling anthropogenic emissions for reducing high O3 concentrations. Biogenic hydrocarbon emissions were adjusted by a factor of 3 to account for the existing range of uncertainty in these emissions. The impact of biogenic emission uncertainties on O3 predictions depended upon the availability of NOx. In some extremely NOx-limited areas, increasing the amount of biogenic emissions decreased O3 concentrations. Two control strategies were compared in the simulations: (1) reduced anthropogenic hydrocarbon emissions, and (2) reduced anthropogenic hydrocarbon and NOx emissions. The simulations showed that hydrocarbon emission controls were more beneficial to the New York City area, but that combined NOx and hydrocarbon controls were more beneficial to other areas of the Northeast. Hydrocarbon controls were more effective as biogenic hydrocarbon emissions were reduced, whereas combined NOx and hydrocarbon controls were more effective as biogenic hydrocarbon emissions were increased

Emission of hydrocarbons and NO{sub x} at low levels of excess air in CFB; Emissioner av kolvaeten och NO{sub x} vid laaga luftoeverskott i CFB

Energy Technology Data Exchange (ETDEWEB)

Schuster, R [TPS Termiska Processer AB, Nykoeping (Sweden)

1995-06-01

Low NO{sub x} operation at low excess air levels heighten the risk of increasing the level of hazardous and polluting emissions from the boiler. These emissions are mainly of two types, greenhouse gases and the mutageneous compounds. The aim of this project has been to show which types of emissions and their correlation you can expect when firing a CFB at low excess air levels. Results: The NO{sub x} emission decreases asymptotically with increased CO-level. High load gives higher NO{sub x} -emissions. There is no significant difference in average NO{sub x} value between wood fuel and RDF-mix. The total hydrocarbon (THC) emission level increases exponentially with increased CO{sub l}evel. There was no significant difference between wood and RDF-mix. Measurements of NO{sub x}, O2, CO (dry gas) and THC were made each second. The measurements of light hydrocarbons (VOC) showed only methane and ethene, both with a good correlation to CO. Below 1000 ppm of CO there is practically no ethene. Above 1000-2000 ppm of CO there is a rapidly increasing emission of ethene. The emission levels at given CO-level are influenced by the furnace temperature. The POM, PNA and Ames test analysis showed good correlation with CO and THC. The results indicate an emission increase at about 200-500 ppm of CO and 10-20 ppm of THC. Dioxin was measured on three occasions with RDF-mix as fuel. The measurements showed an increase of dioxin emission at increased THC-emission. The supply of ammonia, into the flue gas before the cyclones, gave no significant change in hydrocarbon or CO-emission levels. CO, THC and Ames Test are probably good indicators of environmental hazardous compounds. The amount of mutageneous compounds are in general only increased when a certain level of CO is reached. 6 refs, 45 figs, 5 tabs, 7 appendices

Natural attenuation of diesel aliphatic hydrocarbons in contaminated agricultural soil

International Nuclear Information System (INIS)

Serrano, Antonio; Gallego, Mercedes; Gonzalez, Jose Luis; Tejada, Manuel

2008-01-01

A diesel fuel spill at a concentration of 1 L m -2 soil was simulated on a 12 m 2 plot of agricultural land, and natural attenuation of aliphatic hydrocarbons was monitored over a period of 400 days following the spill after which the aliphatic hydrocarbon concentrations were found to be below the legal contamination threshold for soil. The main fraction of these compounds (95%) remained at the surface layer (0-10 cm). Shortly after the spill (viz. between days 0 and 18), evaporation was the main origin of the dramatic decrease in pollutant concentrations in the soil. Thereafter, soil microorganisms used aliphatic hydrocarbons as sources of carbon and energy, as confirmed by the degradation ratios found. Soil quality indicators, soil microbial biomass and dehydrogenase activity, regained their original levels about 200 days after the spill. - The effect of aliphatic hydrocarbons contamination on soil quality was monitored over a period of 400 days after a Diesel fuel spill

Source apportionment of hydrocarbons measured in the Eagle Ford shale

Science.gov (United States)

Roest, G. S.; Schade, G. W.

2016-12-01

The rapid development of unconventional oil and gas in the US has led to hydrocarbon emissions that are yet to be accurately quantified. Emissions from the Eagle Ford Shale in southern Texas, one of the most productive shale plays in the U.S., have received little attention due to a sparse air quality monitoring network, thereby limiting studies of air quality within the region. We use hourly atmospheric hydrocarbon and meteorological data from three locations in the Eagle Ford Shale to assess their sources. Data are available from the Texas commission of environmental quality (TCEQ) air quality monitors in Floresville, a small town southeast of San Antonio and just north of the shale area; and Karnes city, a midsize rural city in the center of the shale. Our own measurements were carried out at a private ranch in rural Dimmit County in southern Texas from April to November of 2015. Air quality monitor data from the TCEQ were selected for the same time period. Non-negative matrix factorization in R (package NMF) was used to determine likely sources and their contributions above background. While the TCEQ monitor data consisted mostly of hydrocarbons, our own data include both CO, CO2, O3, and NOx. We find that rural Dimmit County hydrocarbons are dominated by oil and gas development sources, while central shale hydrocarbons at the TCEQ monitoring sites have a mix of sources including car traffic. However, oil and gas sources also dominate hydrocarbons at Floresville and Karnes City. Toxic benzene is nearly exclusively due to oil and gas development sources, including flaring, which NMF identifies as a major hydrocarbon source in Karnes City. Other major sources include emissions of light weight alkanes (C2-C5) from raw natural gas emissions and a larger set of alkanes (C2-C10) from oil sources, including liquid storage tanks.

A multi-component oil spill model for calculation of evaporation and dissolution of condensate

International Nuclear Information System (INIS)

Rye, H.

1994-01-01

It is sometimes argued that oil spilled on the sea surface will go much faster into evaporation than solution. This statement may not always be true due to effects from wave action. In such cases high concentrations in the water may occur which could be harmful to biologic life below the sea surface. This paper explains a numerical model which simulates the surface spreading of a continuous spill, exposed to currents, wind and wave action. The spill is decomposed into the different constituents present in the spill. The oil or condensate is divided into 20 different classes with increasing carbon number within the interval C4 to C55. Asphalthenes are not included (non-emulgating spill). Within each class, the hydrocarbons are divided further into 5 subsets (n-alcanes, cycloalcanes, aromatics, napthenes and resins). The model then keeps track of what happens to each of the components (evaporation, dissolution, as droplets or remains in the slick) during an actual spill event. The effect of wave action is included by assuming a balance between the downward flux of hydrocarbons caused by the breaking waves, and the upward flux of droplets driven by the boyancy of the droplets. The dissolution and evaporation of the different oil (or spill) components are then computed. The model shows that the evaporation and dissolution may in some cases be competing processes, in particular for the aromatic compounds. The paper outlines the approach chosen, as well as some example results. 16 refs., 2 figs., 4 tabs

Heavy metal evaporation kinetics in thermal waste treatment processes

Energy Technology Data Exchange (ETDEWEB)

Ludwig, Ch; Stucki, S; Schuler, A J [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

To investigate the evaporation kinetics of heavy metals, experiments were performed by conventional thermogravimetry and a new method using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The new method allows online measurements in time intervals that are typically below one minute. The evaporation of Cd, Cu, Pb, and Zn from synthetic mixtures and filter ashes from municipal solid waste incineration (MSWI) was of major interest. (author) 2 figs., 4 refs.

Influence of performance characteristic of a gaseous fuel supply system on hydrocarbon emissions of a dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Ren, J.; Wang, Z.Y.; Zhong, H.; Hao, S.H. [Xi' an Jiaotong Univ., Dept. of Automobile Engineering, Xi' an (China)

2000-11-01

The performance of the gaseous fuel supply and its influence on hydrocarbon (HC) emissions of dual-fuel engines have been investigated. A new design of manifold respirators with mixers is also presented in the paper. The design of the gaseous fuel supply system has a great influence on HC emissions in the dual-fuel engine at light load. The problem of scavenging is discussed and solved by using the manifold respirators in the dual-fuel engine. It performs the function of retarding the gaseous fuel entry timing from the moment of intake valve opening, and its delaying effects have been measured and tested. Experimental results show that the manifold respirator gives the best performance in reducing HC emissions compared with a common pipe mixer and a respirator with bo miser. In addition, the mixing effects are sensitive to the mixer configuration. (Author)

The other GHG : steps taken to reduce CO2 emissions may contribute to increased levels of water vapour in the atmosphere

International Nuclear Information System (INIS)

Collison, M.

2008-01-01

As a result of the Intergovernmental Panel on Climate Change (IPCC), the Canadian oil and gas industry and government are now in the midst of a massive overhaul of hydrocarbon energy use and carbon dioxide (CO 2 ) management. However, human-enhanced water evaporation (HEWE) may also be a significant contributor to global climate warming. Human-caused distortions of the hydrological cycle can cause multiple localized weather disturbances. There is currently a thousand times more water vapor being emitted than CO 2 , and this is contributing to increased rainfall levels around the world. Expansion of the agriculture and growth of industry has caused significant diversions and redistributions of water. Most of the water used is evaporated in the northern hemisphere. Climate modellers are needed to analyze the impacts of human-enhanced water evaporation local climates and weather. The main sources of water emissions are government-controlled energy projects and subsidized irrigation projects. Current levels of water vapour emissions are between 10 and 100 times the value of warming per tonne as CO 2 . Details of various research projects to use salt water as a fuel for vehicles was provided, as well as methods of improving the water-gas shift reaction method of hydrogen production. 2 figs

Evaporation

International Nuclear Information System (INIS)

Delaney, B.T.; Turner, R.J.

1989-01-01

Evaporation has long been used as a unit operation in the manufacture of various products in the chemical-process industries. In addition, it is currently being used for the treatment of hazardous wastes such as radioactive liquids and sludges, metal-plating wastes, and other organic and inorganic wastes. Design choice is dependent on the liquid to be evaporated. The three most common types of evaporation equipment are the rising-film, falling-film, and forced-circulation evaporators. The first two rely on boiling heat transfer and the latter relies on flash vaporization. Heat exchangers, flash tanks, and ejectors are common auxiliary equipment items incorporated with evaporator bodies to complete an evaporator system. Properties of the liquid to be evaporated are critical in final selection of an appropriate evaporator system. Since operating costs are a significant factor in overall cost, heat-transfer characteristics and energy requirements are important considerations. Properties of liquids which are critical to the determination of final design include: heat capacity, heat of vaporization, density, thermal conductivity, boiling point rise, and heat-transfer coefficient. Evaporation is an expensive technology, both in terms of capital costs and operating costs. Additionally, mechanical evaporation produces a condensate and a bottoms stream, one or both of which may require further processing or disposal. 3 figs

The ABAG biogenic emissions inventory project

Science.gov (United States)

Carson-Henry, C. (Editor)

1982-01-01

The ability to identify the role of biogenic hydrocarbon emissions in contributing to overall ozone production in the Bay Area, and to identify the significance of that role, were investigated in a joint project of the Association of Bay Area Governments (ABAG) and NASA/Ames Research Center. Ozone, which is produced when nitrogen oxides and hydrocarbons combine in the presence of sunlight, is a primary factor in air quality planning. In investigating the role of biogenic emissions, this project employed a pre-existing land cover classification to define areal extent of land cover types. Emission factors were then derived for those cover types. The land cover data and emission factors were integrated into an existing geographic information system, where they were combined to form a Biogenic Hydrocarbon Emissions Inventory. The emissions inventory information was then integrated into an existing photochemical dispersion model.

In-situ optical emission spectroscopy for a better control of hybrid sputtering/evaporation process for the deposition of Cu(In,Ga)Se{sub 2} layers

Energy Technology Data Exchange (ETDEWEB)

Posada, Jorge; Jubault, Marie [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF-CNRS-Chimie ParisTech, UMR 7174, 6 Quai Watier, 78401 Chatou (France); Bousquet, Angélique; Tomasella, Eric [Clermont Université, Université Blaise Pascal, Institute of Chemistry of Clermont-Ferrand (ICCF), CNRS-UMR 6296, 24 Avenue des Landais, 63171 Aubière (France); Lincot, Daniel [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF-CNRS-Chimie ParisTech, UMR 7174, 6 Quai Watier, 78401 Chatou (France)

2015-05-01

In this work, we have developed a hybrid one-step co-sputtering/evaporation Cu(In,Ga)Se{sub 2} (CIGS) process, where Cu, In and Ga are sputtered simultaneously with the thermal evaporation of selenium, thus avoiding the H{sub 2}Se use. An appropriate control of the selenium flux is very important to prevent the target poisoning and hence some material flux variations. Indeed, the control of the CIGS composition must be rigorous to ensure reproducible solar cell properties. In this regard, a study of the correlations between plasma species and thin film composition, structure and morphology has been performed by varying power values and Se evaporation temperature in the 170 to 230 °C range. We started by studying the plasma with a powerful technique: optical emission spectroscopy, following light emissions from different plasma species: sputtered Cu, Ga, In but also evaporated Se. Hence, we determined the Se flow threshold avoiding target poisoning and the main parameter controlling the CIGS composition. Obviously, we also focused our interest on the material. We measured film composition and thickness of the samples with X-ray fluorescence and by energy dispersive X-ray. Different phases formed during the process were identified by Raman spectroscopy and X-ray diffraction. The optoelectronic cell properties showed promising efficiency of 10.3% for an absorber with composition ratios of [Cu]/([In] + [Ga]) = 1.02 and [Ga]/([In] + [Ga]) = 0.44. Finally, this work shows that we are able to control this hybrid process and thus the structure and composition of CIGS thin film for industrial transfer in the photovoltaic field. - Highlights: • We have developed a hybrid one-step co-sputtering/evaporation Cu(In,Ga)Se{sub 2} process. • Correlations between plasma species and thin film composition have been performed. • We determined the Se flow threshold avoiding target poisoning. • Efficient small-area CIGS cells with 10.3% efficiency were fabricated.

POLYCYCLIC AROMATIC HYDROCARBON EMISSION IN SPITZER/IRS MAPS. I. CATALOG AND SIMPLE DIAGNOSTICS

Energy Technology Data Exchange (ETDEWEB)

Stock, D. J.; Choi, W. D.-Y.; Moya, L. G. V.; Otaguro, J. N.; Sorkhou, S.; Peeters, E. [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada); Allamandola, L. J. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States); Tielens, A. G. G. M., E-mail: dstock4@uwo.ca [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA (Netherlands)

2016-03-01

We present a sample of resolved galactic H ii regions and photodissociation regions (PDRs) observed with the Spitzer infrared spectrograph in spectral mapping mode between the wavelengths of 5–15 μm. For each object we have spectral maps at a spatial resolution of ∼4″ in which we have measured all of the mid-infrared emission and absorption features. These include the polycyclic aromatic hydrocarbon (PAH) emission bands, primarily at 6.2, 7.7, 8.6, 11.2, and 12.7 μm, as well as the spectral emission lines of neon and sulfur and the absorption band caused by silicate dust at around 9.8 μm. In this work we describe the data in detail, including the data reduction and measurement strategies, and subsequently present the PAH emission band intensity correlations for each of the objects and the sample as a whole. We find that there are distinct differences between the sources in the sample, with two main groups: the first comprising the H ii regions and the second the reflection nebulae (RNe). Three sources—the reflection nebula NGC 7023, the Horsehead nebula PDR (an interface between the H ii region IC 434 and the Orion B molecular cloud), and M17—resist this categorization, with the Horsehead PDR points mimicking the RNe and the NGC 7023 fluxes displaying a unique bifurcated appearance in our correlation plots. These discrepancies seem to be due to the very low radiation field experienced by the Horsehead PDR and the very clean separation between the PDR environment and a diffuse environment in the NGC 7023 observations.

Research and Development of Miniaturized Fuel Evaporation Closed Chamber for Motorcycle

Directory of Open Access Journals (Sweden)

Hong Bin

2016-01-01

Full Text Available With the increasingly serious environmental pollution, pollution emissions of motorcycles had gradually been concerned in all developed countries. But the fuel evaporative emissions had not attracted sufficient attention and its test equipment was far from perfect. Thus, this paper addressed the miniaturized problems of closed chamber. On the basis of analyzing fuel evaporative emission regulations and the features of closed room, technical solutions are determined and a prototype was successfully developed. The paper successfully resolved the seal problem and innovatively developed the pressure balance system and the temperature and humidity regulation system. After experimental verification, the prototype had reliable performance and stable operation. And it met the requirements of the relevant standards and it was also equivalent to imported equipments. Thus, this paper successfully resolved the miniaturized problems of closed chamber.

Global climate change due to the hydrocarbon industry

International Nuclear Information System (INIS)

Almasi, M.; Racz, L.

1999-01-01

An overview is presented on the industry's response to the agreements of the Rio de Janeiro (1992) and Kyoto (1987) conventions on climate change, and to other international agreements. The announcements by large petroleum companies on the changes introduced according to the international commitments in order to fight climatic impacts of hydrocarbon fuels. The problems and foreseeable future of the Hungarian hydrocarbon industry with environmental protection are discussed. Finally, emission abatement and control possibilities of hydrocarbon combustion are considered. (R.P.)

Diffusion and Evaporation-Controlled Emission in Ventilated Rooms

DEFF Research Database (Denmark)

Topp, Claus

and sources. This work provides an investigation based on fundamental fluid dynamics and mass transfer theory to obtain a general understanding of the mechanisms involved in the emission from building materials in ventilated rooms. In addition, a generally applicable model for prediction of surface emission...... is proposed. The interest has been focused on the emission of vapours and gases as no particulate emissions have been considered. The methods used are numerical calculations by computational fluid dynamics (CFD) and full-scale laboratory experiments. It was found that the emission is a strong function of air......In emission studies reported in literature little effort has been made to investigate the emission from building materials in ventilated enclosures from a fluid dynamics point of view. Furthermore, most of the existing emission models are empirical relations that are based on specific pollutants...

Optrode for sensing hydrocarbons

Science.gov (United States)

Miller, H.; Milanovich, F.P.; Hirschfeld, T.B.; Miller, F.S.

1988-09-13

A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons. 5 figs.

Study of mixtures based on hydrocarbons used in ORC (Organic Rankine Cycle) for engine waste heat recovery

International Nuclear Information System (INIS)

Shu, Gequn; Gao, Yuanyuan; Tian, Hua; Wei, Haiqiao; Liang, Xingyu

2014-01-01

For high temperature ORC (Organic Rankine Cycle) used in engine waste heat recovery, it's very critical to select a high temperature working fluid. HCs (Hydrocarbons) usually have excellent cycle performance, but the flammability limits their practical application. Considering that some retardants can be used to suppress flammability, the paper presents an application of mixtures based on hydrocarbons blending with refrigerant retardants to engine waste heat ORC. Three pure hydrocarbons (cyclopentane, cyclohexane, benzene) and two retardants (R11, R123) are selected for combination. Thermal efficiency and exergy loss are selected as the main objective functions. Based on thermodynamic model, the effects of retardants mass fraction, evaporation temperature and IHE (internal heat exchanger) are investigated. Results show that zeotropic mixtures do have higher thermal efficiency and lower exergy loss than pure fluids, at a certain mixture ratio. There exists the OMR (optimal mixture ratio) for different mixtures, and it changes with the evaporation temperature. When adding IHE to system, cycle performance could be obviously improved, and for benzene/R11 (0.7/0.3), the efficiency growth is about 7.12%∼9.72%. Using it, the maximum thermal efficiency of the system can achieve 16.7%, and minimum exergy loss is only 30.76 kW. - Highlights: • A theoretical analysis of Organic Rankine Cycle for engine exhaust heat recovery is proposed. • Mixtures based on hydrocarbons as working fluids have been suggested. • Effects of the IHE (internal heat exchanger) on ORC system are investigated. • OMR (Optimal mixture ratio) changes with the evaporation temperature. • Using the system, maximum thermal efficiency can achieve 16.7%

Estimation of the efficiency of hydrocarbon mineralization in soil by measuring CO2-emission and variations in the isotope composition of carbon dioxide

Science.gov (United States)

Dubrovskaya, Ekaterina; Turkovskaya, Olga

2010-05-01

Estimation of the efficiency of hydrocarbon mineralization in soil by measuring CO2-emission and variations in the isotope composition of carbon dioxide E. Dubrovskaya1, O. Turkovskaya1, A. Tiunov2, N. Pozdnyakova1, A. Muratova1 1 - Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, Saratov, 2 - A.N. Severtsov Institute of Ecology and Evolution, RAS, Moscow, Russian Federation Hydrocarbon mineralization in soil undergoing phytoremediation was investigated in a laboratory experiment by estimating the variation in the 13С/12С ratio in the respired СО2. Hexadecane (HD) was used as a model hydrocarbon pollutant. The polluted soil was planted with winter rye (Secale cereale) inoculated with Azospirillum brasilense strain SR80, which combines the abilities to promote plant growth and to degrade oil hydrocarbon. Each vegetated treatment was accompanied with a corresponding nonvegetated one, and uncontaminated treatments were used as controls. Emission of carbon dioxide, its isotopic composition, and the residual concentration of HD in the soil were examined after two and four weeks. At the beginning of the experiment, the CO2-emission level was higher in the uncontaminated than in the contaminated soil. After two weeks, the quantity of emitted carbon dioxide decreased by about three times and did not change significantly in all uncontaminated treatments. The presence of HD in the soil initially increased CO2 emission, but later the respiration was reduced. During the first two weeks, nonvegetated soil had the highest CO2-emission level. Subsequently, the maximum increase in respiration was recorded in the vegetated contaminated treatments. The isotope composition of plant material determines the isotope composition of soil. The soil used in our experiment had an isotopic signature typical of soils formed by C3 plants (δ13C,-22.4‰). Generally, there was no significant fractionation of the carbon isotopes of the substrates metabolized by the

Emission characteristics and size distribution of polycyclic aromatic hydrocarbons from coke production in China

Science.gov (United States)

Mu, Ling; Peng, Lin; Liu, Xiaofeng; He, Qiusheng; Bai, Huiling; Yan, Yulong; Li, Yinghui

2017-11-01

Coking is regarded as a major source of atmospheric polycyclic aromatic hydrocarbons (PAHs), but few researches have been conducted on the emission characteristics of PAHs from coke production. In this study, emissions of size-segregated particulate matter (PM) and particle-bound PAHs emitted from charging of coal (CC) and pushing of coke (PC) in four typical coke plants were determined. The emission factors on average, sums of CC and PC, were 4.65 mg/kg, 5.96 mg/kg, 19.18 μg/kg and 20.69 μg/kg of coal charged for PM2.1 (≤ 2.1 μm), PM, PAHs in PM2.1 and total-PAHs, respectively. PM and PAHs emission from plants using stamp charging were significantly more than those using top charging. The profile of PAHs in PM with size ≤ 1.4 μm (PM1.4) emitted from CC process were similar with that from PC, however, it revealed obviously different tendency for PAHs in PM with size > 1.4 μm, indicating the different formation mechanism for coarse particles emitted from CC and PC. Size distributions of PM and PAHs indicated that they were primarily connected with PM1.4, and the contributions of PM1.4 to PM and PAHs emitted from the plants using stamp charging were higher than those using top charging. Some improved technology in air-pollution control devices should be considered in coke production in future based on the considerable impacts of PM1.4 and PAHs on human health and ambient air quality.

Emissions from Produced Water Treatment Ponds, Uintah Basin, Utah, USA

Science.gov (United States)

Mansfield, M. L.; Lyman, S. N.; Tran, H.; O'Neil, T.; Anderson, R.

2015-12-01

An aqueous phase, known as "produced water," usually accompanies the hydrocarbon fluid phases that are extracted from Earth's crust during oil and natural gas extraction. Produced water contains dissolved and suspended organics and other contaminants and hence cannot be discharged directly into the hydrosphere. One common disposal method is to discharge produced water into open-pit evaporation ponds. Spent hydraulic fracturing fluids are also often discharged into the same ponds. It is obvious to anyone with a healthy olfactory system that such ponds emit volatile organics to the atmosphere, but very little work has been done to characterize such emissions. Because oil, gas, and water phases are often in contact in geologic formations, we can expect that more highly soluble compounds (e.g., salts, alcohols, carbonyls, carboxyls, BTEX, etc.) partition preferentially into produced water. However, as the water in the ponds age, many physical, chemical, and biological processes alter the composition of the water, and therefore the composition and strength of volatile organic emissions. For example, some ponds are aerated to hasten evaporation, which also promotes oxidation of organics dissolved in the water. Some ponds are treated with microbes to promote bio-oxidation. In other words, emissions from ponds are expected to be a complex function of the composition of the water as it first enters the pond, and also of the age of the water and of its treatment history. We have conducted many measurements of emissions from produced water ponds in the Uintah Basin of eastern Utah, both by flux chamber and by evacuated canister sampling with inverse modeling. These measurements include fluxes of CO2, CH4, methanol, and many other volatile organic gases. We have also measured chemical compositions and microbial content of water in the ponds. Results of these measurements will be reported.

Characterization and concentrations of polycyclic aromatic hydrocarbons in emissions from different heating systems in Damascus, Syria.

Science.gov (United States)

Alkurdi, Farouk; Karabet, François; Dimashki, Marwan

2014-04-01

Traffic has long been recognized as the major contributor to polycyclic aromatic hydrocarbon (PAH) emissions to the urban atmosphere. Stationary combustion sources, including residential space heating systems, are also a major contributor to PAH emissions. The aim of this study was to determine the profile and concentration of PAHs in stack flue gas emissions from different kinds of space heaters in order to increase the understanding of the scale of the PAH pollution problem caused by this source. This study set out to first assess the characteristics of PAHs and their corresponding benzo[a]pyrene equivalent emissions from a few types of domestic heaters and central heating systems to the urban atmosphere. The study, enabled for the first time, the characterization of PAHs in stationary combustion sources in the city of Damascus, Syria. Nine different types of heating systems were selected with respect to age, design, and type of fuel burned. The concentrations of 15 individual PAH compounds in the stack flue gas were determined in the extracts of the collected samples using high-performance liquid chromatography system (HPLC) equipped with ultraviolet-visible and fluorescence detectors. In general, older domestic wood stoves caused considerably higher PAH emissions than modern domestic heaters burning diesel oil. The average concentration of ΣPAH (sum of 15 compounds) in emissions from all types of studied heating systems ranged between 43 ± 0.4 and 316 ± 1.4 μg/m(3). Values of total benzo[a]pyrene equivalent ranged between 0.61 and 15.41 μg/m(3).

Boiling Heat Transfer to Halogenated Hydrocarbon Refrigerants

Science.gov (United States)

Yoshida, Suguru; Fujita, Yasunobu

The current state of knowledge on heat transfer to boiling refrigerants (halogenated hydrocarbons) in a pool and flowing inside a horizontal tube is reviewed with an emphasis on information relevant to the design of refrigerant evaporators, and some recommendations are made for future research. The review covers two-phase flow pattern, heat transfer characteristics, correlation of heat transfer coefficient, influence of oil, heat transfer augmentation, boiling from tube-bundle, influence of return bend, burnout heat flux, film boiling, dryout and post-dryout heat transfer.

Indoor emission, dispersion and exposure of total particle-bound polycyclic aromatic hydrocarbons during cooking

Science.gov (United States)

Gao, Jun; Jian, Yating; Cao, Changsheng; Chen, Lei; Zhang, Xu

2015-11-01

Cooking processes highly contribute to indoor polycyclic aromatic hydrocarbon (PAH) pollution. High molecular weight and potentially carcinogenic PAHs are generally found attached to small particles, i.e., particulate phase PAHs (PPAHs). Due to the fact that indoor particle dynamics have been clear, describing the indoor dynamics of cooking-generated PPAHs within a specific time span is possible. This paper attempted to quantify the dynamic emission rate, simultaneous spatial dispersion and individual exposure of PPAHs using a cooking source. Experiments were conducted in a real-scale kitchen chamber to elucidate the time-resolved emission and effect of edible oil temperature and mass. Numerical simulations based on indoor particle dynamics were performed to obtain the spatial dispersion and individual inhalation intake of PPAHs under different emission and ventilation conditions. The present work examined the preheating cooking stage, at which edible oil is heated up to beyond its smoke point. The dynamic emission rate peak point occurred much earlier than the oil heating temperature. The total PPAH emission ranged from 2258 to 6578 ng upon heating 40-85 g of edible oil. The overall intake fraction by an individual within a period of 10 min, including 3 min for heating and 7 min for natural cooling, was generally ∼1/10,000. An important outcome of this work was that the overall intake fraction could be represented by multiplying the range hood escape efficiency by the inhalation-to-ventilation rate ratio, which would be no greater than the same ratio. The methodology and results of this work were extendible for the number-based assessment of PPAHs. This work is expected to help us understand the health risks due to inhalation exposure to cooking-generated PPAHs in the kitchen.

Dewaxing hydrocarbon oils. [British patent

Energy Technology Data Exchange (ETDEWEB)

1933-06-23

In dewaxing hydrocarbon oils such as residium stocks, overhead distillates and crude petroleum or shale oils, by admixing with a liquefied normally gaseous solvent, such as liquefied propane, and cooling to crystallize the wax, the rate of crystallization diminishes rapidly when a certain temperature in an example about 20/sup 0/F is reached. The diminution is prevented during further cooling by removing solvent by evaporation at such a rate that the proporation of solvent in the oil solvent component is maintained at about that existing at the temperature at which the alteration in the rate of crystallization takes place. The evaporation is effected by adjusting the pressure on the mixture, preferably in stages. Solvents for coloring matters and asphaltic compounds, such as carbon disulfide sulfur dioxide, methyl chloride or butyl alcohol may be added to the mixture before crystallization. Chilled solvent may be added to the chilled mixture before separation of the wax in a centrifuge, in order to increase the difference in specific gravity between the wax and the oil-solvent component.

Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons. [in interstellar medium

Science.gov (United States)

Bauer, S. H.; Borchardt, D. B.

1990-01-01

The wavelength range of a previously constructed multichannel fast recording spectrometer was extended to the mid-infrared. With the initial configuration, light intensities were recorded simultaneously with a silicon-diode array simultaneously at 20 adjacent wavelengths, each with a 20-micron time resolution. For studies in the infrared, the silicon diodes were replaced by a 20-element PbSe array of similar dimensions, cooled by a three-stage thermoelectric device. It is proposed that infrared emissions could be due to shock-heated low molecular-weight hydrocarbons. The full Swan band system appeared in time-integrated emission spectra from shock-heated C2H2; no soot was generated. At low resolution, the profiles on the high-frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no conversion) and T5(eq).

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

2012-06-05

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.

Effects of biodiesel on emissions of regulated air pollutants and polycyclic aromatic hydrocarbons under engine durability testing

International Nuclear Information System (INIS)

Hsi-Hsien Yang; Shu-Mei Chien; Mei-Yu Lo; John Chi-Wei Lan; Wen-Chang Lu; Yong-Yuan Ku

2007-01-01

An 80,000-km durability test was performed on two engines using diesel and biodiesel (methyl ester of waste cooking oil) as fuel in order to examine emissions resulting from the use of biodiesel. The test biodiesel (B20) was blended with 80% diesel and 20% methyl ester derived from waste cooking oil. Emissions of regulated air pollutants, including CO, HC, NO x , particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) were measured at 20,000-km intervals. The identical-model engines were installed on a standard dynamometer equipped with a dilution tunnel used to measure the pollutants. To simulate real-world driving conditions, emission measurements were made in accordance with the United States Environmental Protection Agency (USEPA) FTP transient cycle guidelines. At 0 km of the durability test, HC, CO and PM emission levels were lower for the B20 engine than those for diesel. After running for 20,000 km and longer, they were higher. However, the deterioration coefficients for these regulated air pollutants were not statistically higher than 1.0, implying that the emission factors do not increase significantly after 80,000 km of driving. Total (gaseous+particulate phase) PAH emission levels for both B20 and diesel decreased as the driving mileage accumulated. However, for the engine using B20 fuel, particulate PAH emissions increased as engine mileage increased. The average total PAH emission factors were 1097 and 1437 μg bhp h -1 for B20 and diesel, respectively. For B20, the benzo[a]pyrene equivalence emission factors were 0.77, 0.24, 0.20, 7.48, 5.43 and 14.1 μg bhp h -1 for 2-, 3-, 4-, 5-, 6-ringed and total PAHs. Results show that B20 use can reduce both PAH emission and its corresponding carcinogenic potency. (author)

Effects of biodiesel on emissions of regulated air pollutants and polycyclic aromatic hydrocarbons under engine durability testing

Energy Technology Data Exchange (ETDEWEB)

Hsi-Hsien Yang; Shu-Mei Chien; Mei-Yu Lo [Chaoyang University of Technology, Wufong (China). Dept. of Environmental Engineering and Management; John Chi-Wei Lan [Yuan Ze University (China). Dept. of Chemical Engineering and Materials Science; Wen-Chang Lu [Industrial Technology Research Institute, Hsinchu (China). New Energy Div.; Yong-Yuan Ku [Automotive Research and Testing Center, Chunhwa (China). Diesel Vehicle Section

2007-11-15

An 80,000-km durability test was performed on two engines using diesel and biodiesel (methyl ester of waste cooking oil) as fuel in order to examine emissions resulting from the use of biodiesel. The test biodiesel (B20) was blended with 80% diesel and 20% methyl ester derived from waste cooking oil. Emissions of regulated air pollutants, including CO, HC, NO{sub x}, particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) were measured at 20,000-km intervals. The identical-model engines were installed on a standard dynamometer equipped with a dilution tunnel used to measure the pollutants. To simulate real-world driving conditions, emission measurements were made in accordance with the United States Environmental Protection Agency (USEPA) FTP transient cycle guidelines. At 0 km of the durability test, HC, CO and PM emission levels were lower for the B20 engine than those for diesel. After running for 20,000 km and longer, they were higher. However, the deterioration coefficients for these regulated air pollutants were not statistically higher than 1.0, implying that the emission factors do not increase significantly after 80,000 km of driving. Total (gaseous+particulate phase) PAH emission levels for both B20 and diesel decreased as the driving mileage accumulated. However, for the engine using B20 fuel, particulate PAH emissions increased as engine mileage increased. The average total PAH emission factors were 1097 and 1437 {mu}g bhp h{sup -1} for B20 and diesel, respectively. For B20, the benzo[a]pyrene equivalence emission factors were 0.77, 0.24, 0.20, 7.48, 5.43 and 14.1 {mu}g bhp h{sup -1} for 2-, 3-, 4-, 5-, 6-ringed and total PAHs. Results show that B20 use can reduce both PAH emission and its corresponding carcinogenic potency. (author)

Evaporative cycles - in theory and in practise

Energy Technology Data Exchange (ETDEWEB)

Rosen, P.M.

2000-08-01

operation in three reversible steps: 1. Simple open gas turbine cycle; 2. Recuperative gas turbine cycle; 3. Evaporative gas turbine cycle. The braked efficiency of the gas turbine engine increased from 22% for the simple cycle to 35% for the evaporative cycle. The NO{sub x} was reduced by about 90% for the evaporative cycle compared to the simple cycle. Single digit NO{sub x} emission levels were measured in the normal operation interval using a simple diffusion flame combustion chamber operating on natural gas. However, the pilot plant has been optimised neither for best performance nor for best emissions values; instead the main goal was just to show an operable evaporative gas turbine unit and to verify performance calculations. During the work, a spin-off idea, the HAM-concept (Humid Air Motor), was introduced. In the HAM-concept, a turbo-charged reciprocate combustion engine is equipped with a humidification tower situated between the turbo-charger and the engine. This action reduces NO{sub x} emissions and raises the efficiency of the engine, and at the same time, operates as an online cleaning device of the engine. Today this concept has been demonstrated in a full scale marine retrofit application with good results. In fact, the HAM-concept is presently on the brink of being commercialised. In the struggle to find a good cogeneration solution of the evaporative cycles and at the same time to close the water loop completely, one new idea further arose. This new concept is presented for the first time in this thesis. The concept is called the 'The TRIGENERATION Technology' due to its possibility of offering three benefits from one cycle. These cycles will have the possibility of reaching higher than 100% total efficiency even if the performance calculations are based on the higher heating value of the fuel. Due to the stable and thermodynamically favourable way the pressurised humidification tower operates in evaporative cycles, its compactness, combined

Hydrocarbon Source Signatures in Houston, Texas: Influence of the Petrochemical Industry

Energy Technology Data Exchange (ETDEWEB)

Jobson, B Tom T; Berkowitz, Carl M; Kuster, W C; Goldan, P D; Williams, E J; Fesenfeld, F; Apel, Eric; Karl, Thomas G; Lonneman, William A; Riemer, D

2004-12-22

Observations of C1-C10 hydrocarbon mixing ratios measured by in-situ instrumentation at the La Porte super site during the TexAQS 2000 field experiment are reported. The La Porte data were compared to a roadway vehicle exhaust signature obtained from canister samples collected in the Houston Washburn tunnel during the same summer to better understand the impact of petrochemical emissions of hydrocarbons at the site. It is shown that the abundance of ethene, propene, 1-butene, C2-C4 alkanes, hexane, cyclohexane, methylcyclohexane, isopropylbenzene, and styrene at La Porte were systematically impacted by petrochemical industry emissions. Coherent power law relationships between frequency distribution widths of hydrocarbon mixing ratios and their local lifetimes clearly identify two major source groups, roadway vehicle emissions and industrial emissions. Distributions of most aromatics and long chain alkanes were consistent with roadway vehicle emissions as the dominant source. Airmass reactivity was generally dominated by C1-C3 aldehydes. Propene and ethene sometimes dominated air mass reactivity with HO loss frequencies often greater than 10 s-1. Ozone mixing ratios near 200 ppbv were observed on two separate occasions and these air masses appear to have been impacted by industrial emissions of alkenes from the Houston Ship Channel. The La Porte data provide evidence of the importance of industrial emissions of ethene and propene on air masses reactivity and ozone formation in Houston.

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.

Hydrocarbon source apportionment for the 1996 Paso del Norte Ozone Study

Energy Technology Data Exchange (ETDEWEB)

Fujita, E.M. [Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89506-0220 (United States)

2001-08-10

The 1996 Paso del Norte (PdN) ozone study was conducted to improve current understanding of the significant meteorological and air quality processes that lead to high concentrations of ozone in El Paso, Texas (USA) and Ciudad Juarez, Chihuahua (Mexico). Two-hour canister samples were collected five times daily at 05.00-07.00 h, 07.00-09.00 h, 09.00-11.00 h, 11.00-13.00 h, and 15.00-17.00 h MST during intensive study periods at one urban and one rural site on each side of the border. An automated gas chromatograph was operated at one site in central El Paso. Source profiles (the fractional chemical composition of emissions) from motor vehicles, gasoline, liquefied petroleum gas, and commercial natural gas were combined with source profiles from other studies for input to the Chemical Mass Balance (CMB) receptor model to apportion the measured non-methane hydrocarbons (NMHC) to sources. On-road vehicle emissions accounted for one-half to two-thirds of the NMHC in Ciudad Juarez and El Paso with the highest contributions occurring during the morning and afternoon commute periods. Emissions from diesel exhaust contributed approximately 2-3% of NMHC in Ciudad Juarez and less than 2% in El Paso. The average sum of liquid gasoline and gasoline vapor increased during the day in Ciudad Juarez from 2% at 06.00 h to approximately 12% at 16.00 h. Diurnal and day-of-the-week patterns in the liquid gasoline contributions are essentially identical to the corresponding patterns for motor vehicle exhaust, which suggest that a large fraction of the liquid gasoline contribution may be associated with tailpipe emissions rather than evaporative emissions from motor vehicles or industrial sources. Including the sum of the two sources put the upper limit for tailpipe contributions at 60-70% of NMHC.

Black carbon and polycyclic aromatic hydrocarbon emissions from vehicles in the United States-Mexico border region: pilot study.

Science.gov (United States)

Kelly, Kerry; Wagner, David; Lighty, JoAnn; Quintero Núñez, Margarito; Vazquez, F Adrian; Collins, Kimberly; Barud-Zubillaga, Alberto

2006-03-01

The investigators developed a system to measure black carbon (BC) and particle-bound polycyclic aromatic hydrocarbon (PAH) emission factors during roadside sampling in four cities along the United States-Mexico border, Calexico/Mexicali and El Paso/Juarez. The measurement system included a photoacoustic analyzer for BC, a photoelectric aerosol sensor for particle-bound PAHs, and a carbon dioxide (CO2) analyzer. When a vehicle with measurable emissions passed the system probe, corresponding BC, PAH, and CO2 peaks were evident, and a fuel-based emission factor was estimated. A picture of each vehicle was also recorded with a digital camera. The advantage of this system, compared with other roadside methods, is the direct measurement of particulate matter components and limited interference from roadside dust. The study revealed some interesting trends: Mexican buses and all medium-duty trucks were more frequently identified as high emitters of BC and PAH than heavy-duty trucks or passenger vehicles. In addition, because of the high daily mileage of buses, they are good candidates for additional study. Mexican trucks and buses had higher average emission factors compared with U.S. trucks and buses, but the differences were not statistically significant. Few passenger vehicles had measurable BC and PAH emissions, although the highest emission factor came from an older model passenger vehicle licensed in Baja California.

Time-resolved analysis of particle emissions from residential biomass combustion - Emissions of refractory black carbon, PAHs and organic tracers

Science.gov (United States)

Nielsen, Ingeborg E.; Eriksson, Axel C.; Lindgren, Robert; Martinsson, Johan; Nyström, Robin; Nordin, Erik Z.; Sadiktsis, Ioannis; Boman, Christoffer; Nøjgaard, Jacob K.; Pagels, Joakim

2017-09-01

Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of

Study of hydrocarbon emission in small direct injection engines; Kogata DI diesel kikan ni okeru teifukaji HC haishutsu ni kansuru kiso kenkyu

Energy Technology Data Exchange (ETDEWEB)

Tsurushima, T; Zhang, L; Ueda, T; Fujino, R; Yokota, K [Isuzu Advanced Engineering Center, Tokyo (Japan)

1997-10-01

The cause of unburned hydrocarbon emission in small DI diesel engines at light load was studied. An optically accessible engine which was enabled to visualize the squish area was used to investigate the behavior of spray, mixture distribution and so on. Based on these observations and engine tests, the factors such as the direct impingement of liquid phase fuel spray to the combustion chamber wall the unevenness of fuel spray among holes and spreading of the fuel droplets, mixture and flame to the squish area were supposed to be the cause of forming HC emission. 18 refs., 10 figs., 2 tabs.

Influence of glass furnace operational conditions on the evaporation from soda-lime and borosilicate glass melts.

NARCIS (Netherlands)

Beerkens, R.G.C.

2000-01-01

The evaporation of sodium and boron species from the melts in industrial glass furnaces leads to emissions of particulates (dust) and to furnace atmospheres containing reactive evaporation products. These reactive species, especially alkali vapors, can react with the superstructure refractories

242-A Evaporator waste analysis plan. Revision 4

International Nuclear Information System (INIS)

Basra, T.S.; Mulkey, C.H.

1994-01-01

This waste analysis plan (WAP) provides the plan for obtaining information needed for proper waste handling and processing in the 242-A Evaporator located on the Hanford Site. Regulatory and safety issues are addressed by establishing boundary conditions for waste received and treated at the 242-A Evaporator. The boundary conditions are set by establishing limits for items such as potential exothermic reactions, waste compatibility, and control of vessel vent organic emissions. Boundary conditions are also set for operational considerations and to ensure waste acceptance at receiving facilities. The issues that are addressed in this plan include prevention of exotherms in the waste, waste compatibility, vessel vent emissions, and compatibility with the liner in the Liquid Effluent Retention Facility (LERF). The 242-A Evaporator feed stream is separated into two liquid streams: a concentrated slurry stream and a process condensate. A gaseous exhaust stream is also produced. The slurry contains the majority of the radionuclides and inorganic constituents. This stream is pumped back to the double shell tanks (DSTs) and stored for further treatment after being concentrated to target levels. The process condensate (PC) is primarily water that contains trace amounts of organic material and a greatly reduced concentration of radionuclides. The process condensate is presently stored in the (LERF) until it can be further processed in the Effluent Treatment Facility once it is operational

Evaporator line for special electron tubes, in particular electron multipliers

International Nuclear Information System (INIS)

Richter, M.

1984-01-01

The invention has been aimed at reducing the effort for preventing short circuits in achieving certain material-dependent effects e.g. secondary emission, by deposition through evaporation in the production of electron tubes, in particular electron multipliers

Efficiency Analysis of Technological Methods for Reduction of NOx Emissions while Burning Hydrocarbon Fuels in Heat and Power Plants

Directory of Open Access Journals (Sweden)

S. M. Kabishov

2013-01-01

Full Text Available The paper contains a comparative efficiency analysis pertaining to application of existing technological methods for suppression of nitric oxide formation in heating boilers of heat generators. A special attention has been given to investigation of NOx  emission reduction while burning hydrocarbon fuel with the help of oxygen-enriched air. The calculations have demonstrated that while enriching oxidizer with the help of oxygen up to 50 % (by volume it is possible to reduce volume of NOx formation (while burning fuel unit by 21 %.

Miniature electron bombardment evaporation source: evaporation rate measurement

International Nuclear Information System (INIS)

Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

1997-01-01

Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

The reformation of liquid hydrocarbons in an aqueous discharge reactor

International Nuclear Information System (INIS)

Zhang, Xuming; Cha, Min Suk

2015-01-01

We present an aqueous discharge reactor for the reformation of liquid hydrocarbons. To increase a dielectric constant of a liquid medium, we added distilled water to iso-octane and n-dodecane. As expected, we found decreased discharge onset voltage and increased discharge power with increased water content. Results using optical emission spectroscopy identified OH radicals and O atoms as the predominant oxidative reactive species with the addition of water. Enriched CH radicals were also visualized, evidencing the existence of cascade carbon–carbon cleavage and dehydrogenation processes in the aqueous discharge. The gaseous product consisted primarily of hydrogen, carbon monoxide, and unsaturated hydrocarbons. The composition of the product was readily adjustable by varying the volume of water added, which demonstrated a significant difference in composition with respect to the tested liquid hydrocarbon. In this study, we found no presence of CO 2 emissions or the contamination of the reactor by solid carbon deposition. These findings offer a new approach to the reforming processes of liquid hydrocarbons and provide a novel concept for the design of a practical and compact plasma reformer. (paper)

Some cosmological consequences of primordial black-hole evaporations

International Nuclear Information System (INIS)

Carr, B.J.

1976-01-01

According to Hawking, primordial black holes of less than 10 15 g would have evaporated by now. This paper examines the way in which small primordial black holes could thereby have contributed to the background density of photons, nucleons, neutrinos, electrons, and gravitons in the universe. Any photons emitted late enough should maintain their emission temperature apart from a redshift effect: it is shown that the biggest contribution should come from primordial black holes of about 10 15 g, which evaporate in the present era, and it is argued that observations of the γ-ray background indicate that primordial black holes of this size must have a mean density less than 10 -8 times the critical density. Photons which were emitted sufficiently early to be thermalized could, in principle, have generated the 3 K background in an initially cold universe, but only if the density fluctuations in the early universe had a particular form and did not extend up to a mass scale of 10 15 g. Primordial black holes of less than 10 14 g should emit nucleons: it is shown that such nucleons could not contribute appreciably to the cosmic-ray background. However, nucleon emission could have generated the observed number density of baryons in an initially baryon-symmetric universe, provided some CP-violating process operates in black hole evaporations such that more baryons are always produced than antibaryons. We predict the spectrum of neutrinos, electrons, and gravitons which should result from primordial black-hole evaporations and show that the observational limits on the background electron flux might place a stronger limitation on the number of 10 15 g primordial black holes than the γ-ray observations. Finally, we examine the limits that various observations place on the strength of any long-range baryonic field whose existence might be hypothesized as a means of preserving baryon number in black-hole evaporations

On the mechanism of fission neutron emission

International Nuclear Information System (INIS)

Maerten, H.; Richter, D.; Seeliger, D.

1986-01-01

This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

Influence of evaporation conditions of Alq3 on the performance of organic light emitting diodes

International Nuclear Information System (INIS)

Zhang Fujun; Xu Zheng; Zhao Dewei; Zhao Suling; Jiang Weiwei; Yuan Guangcai; Song Dandan; Wang Yongsheng; Xu Xurong

2007-01-01

The influence of evaporation conditions of organic semiconductor material tris(8-hydroxyquinoline)aluminium (Alq 3 ) on the performance of organic light emitting diodes (OLEDs) is reported. In the process of organic material thermal evaporation, the chamber was dark or had white light from a 100 W filament lamp. The devices prepared in the dark show higher emission intensity and efficiency compared with the ones prepared in white light under the same driving voltage. Atomic force microscopy measurements show that surface morphology and phase of Alq 3 thin films are quite different for the previous cases. The different evaporation conditions are found to have direct effects on the electrical and luminance performance. The Alq 3 thin films prepared in the dark as active emission layers of OLEDs show higher intensity and efficiency

Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in particulates emitted by motorcycles

International Nuclear Information System (INIS)

Pham, Chau Thuy; Kameda, Takayuki; Toriba, Akira; Hayakawa, Kazuichi

2013-01-01

We determined eleven PAHs and four NPAHs in particulates and regulated pollutants (CO, CO 2 , HC, NO x , PM) exhausted from motorcycles to figure out the characteristics of motorcycle exhausts. Fluoranthene and pyrene accounted for more than 50% of the total detected PAHs. Among four detected NPAHs, 6-nitrochrysene and 7-nitrobenz[a]anthracene were the predominant NPAHs and were highly correlated relationship with their parent PAHs (R = 0.93 and 0.97, respectively). The PM and HC emissions tended to be close to the PAH emissions. NO x and NPAHs were negatively correlated. Despite their small engine size, motorcycles emitted much more PM and PAHs, showed stronger PAH-related carcinogenicity and indirect-acting mutagenicity, but weaker NPAH-related direct-acting mutagenic potency than automobiles. This is the first study to analyze both PAHs and NPAHs emitted by motorcycles, which could provide useful information to design the emission regulations and standards for motorcycles such as PM. -- Highlights: ► We characterized PAHs and NPAHs distribution in motorcycle exhausts. ► NPAHs concentrations were about three orders of magnitude lower than those of PAHs. ► We found larger amounts of PM and PAHs in exhaust of motorcycles than of automobiles. ► Motorcycles showed stronger PAH-related toxicity than automobiles. ► Motorcycles showed weaker NPAH-related direct-acting mutagenicity than automobiles. -- Control polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbon in particulates emitted by motorcycles due to their toxic potency

Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity

Science.gov (United States)

Hicks, Michael C.; Dietrich, Daniel L.; Nayagam, Vedha; Williams, Forman A.

2012-01-01

The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent heat of condensation of water vapor, released into the droplet, enhances its burning rate, whereas later there is a water-evaporation period, during which the water vapor reduces the flame temperature suffciently to extinguish the flame. Recent methanol droplet-combustion experiments in ambient environments diluted with carbon dioxide, conducted in the Combustion Integrated Rack on the International Space Station (ISS), as a part of the FLEX project, provided a method to delineate the water-absorption period from the water-evaporation period using video images of flame intensity. These were obtained using an ultra-violet camera that captures the OH* radical emission at 310 nm wavelength and a color camera that captures visible flame emission. These results are compared with results of ground-based tests in the Zero Gravity Facility at the NASA Glenn Research Center which employed smaller droplets in argon-diluted environments. A simplified theoretical model developed earlier correlates the transition time at which water absorption ends and evaporation starts. The model results are shown to agree reasonably well with experiment.

A study of light hydrocarbons (C{sub 4}-C{sub 1}3) in source rocks and petroleum fluid

Energy Technology Data Exchange (ETDEWEB)

Odden, Wenche

2000-07-01

This thesis consists of an introduction and five included papers. Of these, four papers are published in international journals and the fifth was submitted for review in April 2000. Emphasis has been placed on both naturally and artificially generated light hydrocarbons in petroleum fluids and their proposed source rocks as well as direct application of light hydrocarbons to oil/source rock correlations. Collectively, these papers describe a strategy for interpreting the source of the light hydrocarbons in original oils and condensates as well as the source of the asphaltene fractions from the reservoir fluids. The influence of maturity on light hydrocarbon composition has also been evaluated. The papers include (1) compositional data on the light hydrocarbons from thermal extracts and kerogen pyrolysates of sediment samples, (2) light hydrocarbon data of oils and condensates as well as the pyrolysis products of the asphaltenes from these fluids, (3) assessment of compositional alteration effects, such as selective losses of light hydrocarbons due to evaporation, thermal maturity, phase fractionation and biodegradation, (4) comparison of naturally and artificially generated light hydrocarbons, and (5) compound-specific carbon isotope analysis of the whole range of hydrocarbons of all sample types. (author)

Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

Science.gov (United States)

Fang, Zheng; Deng, Wei; Zhang, Yanli; Ding, Xiang; Tang, Mingjin; Liu, Tengyu; Hu, Qihou; Zhu, Ming; Wang, Zhaoyi; Yang, Weiqiang; Huang, Zhonghui; Song, Wei; Bi, Xinhui; Chen, Jianmin; Sun, Yele; George, Christian; Wang, Xinming

2017-12-01

Agricultural residues are among the most abundant biomass burned globally, especially in China. However, there is little information on primary emissions and photochemical evolution of agricultural residue burning. In this study, indoor chamber experiments were conducted to investigate primary emissions from open burning of rice, corn and wheat straws and their photochemical aging as well. Emission factors of NOx, NH3, SO2, 67 non-methane hydrocarbons (NMHCs), particulate matter (PM), organic aerosol (OA) and black carbon (BC) under ambient dilution conditions were determined. Olefins accounted for > 50 % of the total speciated NMHCs emission (2.47 to 5.04 g kg-1), indicating high ozone formation potential of straw burning emissions. Emission factors of PM (3.73 to 6.36 g kg-1) and primary organic carbon (POC, 2.05 to 4.11 gC kg-1), measured at dilution ratios of 1300 to 4000, were lower than those reported in previous studies at low dilution ratios, probably due to the evaporation of semi-volatile organic compounds under high dilution conditions. After photochemical aging with an OH exposure range of (1.97-4.97) × 1010 molecule cm-3 s in the chamber, large amounts of secondary organic aerosol (SOA) were produced with OA mass enhancement ratios (the mass ratio of total OA to primary OA) of 2.4-7.6. The 20 known precursors could only explain 5.0-27.3 % of the observed SOA mass, suggesting that the major precursors of SOA formed from open straw burning remain unidentified. Aerosol mass spectrometry (AMS) signaled that the aged OA contained less hydrocarbons but more oxygen- and nitrogen-containing compounds than primary OA, and carbon oxidation state (OSc) calculated with AMS resolved O / C and H / C ratios increased linearly (p < 0.001) with OH exposure with quite similar slopes.

Identifying future directions for subsurface hydrocarbon migration research

Science.gov (United States)

Leifer, I.; Clark, J. F.; Luyendyk, B.; Valentine, D.

Subsurface hydrocarbon migration is important for understanding the input and impacts of natural hydrocarbon seepage on the environment. Great uncertainties remain in most aspects of hydrocarbon migration, including some basic mechanisms of this four-phase flow of tar, oil, water, and gas through the complex fracture-network geometry particularly since the phases span a wide range of properties. Academic, government, and industry representatives recently attended a workshop to identify the areas of greatest need for future research in shallow hydrocarbon migration.Novel approaches such as studying temporal and spatial seepage variations and analogous geofluid systems (e.g., geysers and trickle beds) allow deductions of subsurface processes and structures that remain largely unclear. Unique complexities exist in hydrocarbon migration due to its multiphase flow and complex geometry, including in-situ biological weathering. Furthermore, many aspects of the role of hydrocarbons (positive and negative) in the environment are poorly understood, including how they enter the food chain (respiration, consumption, etc.) and “percolate” to higher trophic levels. But understanding these ecological impacts requires knowledge of the emissions' temporal and spatial variability and trajectories.

Solo Mycoremediation Impacted by Waste Hydrocarbons

Directory of Open Access Journals (Sweden)

Franklin Santos Freire

2015-06-01

Full Text Available Oil and its derivatives are the principal means of energy generation for vehicles that transport raw materials and goods produced in developed and developing regions accentuating the risk of accidents by spills in stockpiling, transport, use or discarding. The contamination by total hydrocarbons suggests the elevated propension to mutations and to the formation of carcinogenic tumors, as a consequence of the exposure to human contamination by these products. This work had as aims: a To investigate, in a laboratorial scale, the degrading capacity of autochthonous microbiota in the presence of differing concentrations of hydrocarbons (0%, 2,5%, 5% e 7,5%; b To isolate fungi tolerant to the contaminant; c To quantify and analyze the biodegradation capacity of soil through the microbial biomass and metabolic quotient; and d To set, in laboratory, ideal conditions of biodegradation of the xenobiotic compound. Some parameters of microbial activity have been evaluated, such as: biological (Carbon of microbial biomass, CO2 , qCO2 emission, and fungi growth, chemical (pH, electrical conductivity –EC –, analysis of fertility and total hydrocarbons and physical (physical composition of the soil for analysis and comparisons. The obtained results suggest that the adding of 5% of waste oil in the ground provided ideal condition for the biodegradation of he   contaminant in the environment. From the evaluated parameters, the emission of CO2 and microbial C were considered more indicative of changes in soil microbial activity subject to the addition of hydrocarbons, confirming the possibility of microremediation use.

Criteria and air-toxic emissions from in-use automobiles in the National Low-Emission Vehicle program.

Science.gov (United States)

Baldauf, Rich W; Gabele, Pete; Crews, William; Snow, Richard; Cook, J Rich

2005-09-01

The U.S. Environmental Protection Agency (EPA) implemented a program to identify tailpipe emissions of criteria and air-toxic contaminants from in-use, light-duty low-emission vehicles (LEVs). EPA recruited 25 LEVs in 2002 and measured emissions on a chassis dynamometer using the cold-start urban dynamometer driving schedule of the Federal Test Procedure. The emissions measured included regulated pollutants, particulate matter, speciated hydrocarbon compounds, and carbonyl compounds. The results provided a comparison of emissions from real-world LEVs with emission standards for criteria and air-toxic compounds. Emission measurements indicated that a portion of the in-use fleet tested exceeded standards for the criteria gases. Real-time regulated and speciated hydrocarbon measurements demonstrated that the majority of emissions occurred during the initial phases of the cold-start portion of the urban dynamometer driving schedule. Overall, the study provided updated emission factor data for real-world, in-use operation of LEVs for improved emissions modeling and mobile source inventory development.

Probing the spin multiplicity of gas-phase polycyclic aromatic hydrocarbons through their infrared emission spectrum: a theoretical study.

Science.gov (United States)

Falvo, Cyril; Calvo, Florent; Parneix, Pascal

2012-08-14

The anharmonic infrared emission spectrum following an optical excitation has been calculated for a variety of polycyclic aromatic hydrocarbon molecules in their ground singlet electronic state or in their triplet state. The computational protocol relies on second-order perturbation theory and involves a quartic vibrational Hamiltonian, the vibrational quantum numbers being sampled according to a Monte Carlo procedure. In the case of neutral naphthalene, the IR spectrum obtained in the (ground) singlet state differs significantly from the spectrum in the triplet state, especially for out-of-plane CH bending modes. Although not as prominent, spectral differences in larger molecules are still observable.

Preliminary evaluation of a method using an FID (flame ionization detector) for measurement of methanol in auto emissions. Final report

International Nuclear Information System (INIS)

Gabele, P.A.; Ray, W.D.; Duncan, J.; Burton, C.

1987-09-01

This report evaluates a simplified technique for estimating methanol emission rates in auto exhaust. The technique, referred to as the FID Bubbled Method or FBM, is based in principle on the fact that, while hydrocarbons are not readily absorbed in water, methanol is. Hence, by using a heated flame ionization detector to measure the organic mass in samples before and after bubbling them in water, the quantity of methanol originally present can be estimated by taking the difference between the measurements. Evaluation of the method was done by comparing methanol measurements using the FBM with measurements made using an established reference method. Results showed poor to fair agreement between the two methods. The FBM appeared better at estimating methanol emission rates from evaporative tests than from exhaust tests and also exhibited better accuracy for samples containing higher levels of methanol

Numerical Investigation of AdBlue Droplet Evaporation and Thermal Decomposition in the Context of NOx-SCR Using a Multi-Component Evaporation Model

Directory of Open Access Journals (Sweden)

Kaushal Nishad

2018-01-01

Full Text Available To cope with the progressive tightening of the emission regulations, gasoline and diesel engines will continuously require highly improved exhaust after-treatment systems. In the case of diesel engines, the selective catalytic reduction (SCR appears as one of the widely adopted technologies to reduce NOx (nitrogen oxides emissions. Thereby, with the help of available heat from exhaust gas, the injected urea–water solution (UWS turns inside the exhaust port immediately into gaseous ammonia (NH3 by evaporation of mixture and thermal decomposition of urea. The reaction and conversion efficiency mostly depend upon the evaporation and subsequent mixing of the NH3 into the exhaust gas, which in turn depends upon the engine loading conditions. Up to now, the aggregation of urea after evaporation of water and during the thermal decomposition of urea is not clearly understood. Hence, various scenarios for the urea depletion in the gaseous phase that can be envisaged have to be appraised under SCR operating conditions relying on an appropriate evaporation description. The objective of the present paper is therefore fourfold. First, a reliable multi-component evaporation model that includes a proper binary diffusion coefficient is developed for the first time in the Euler–Lagrangian CFD (computational fluid dynamics framework to account properly for the distinct evaporation regimes of adBlue droplets under various operating conditions. Second, this model is extended for thermal decomposition of urea in the gaseous phase, where, depending on how the heat of thermal decomposition of urea is provided, different scenarios are considered. Third, since the evaporation model at and around the droplet surface is based on a gas film approach, how the material properties are evaluated in the film influences the process results is reported, also for the first time. Finally, the impact of various ambient temperatures on the adBlue droplet depletion characteristics

Estimating evaporative vapor generation from automobiles based on parking activities

International Nuclear Information System (INIS)

Dong, Xinyi; Tschantz, Michael; Fu, Joshua S.

2015-01-01

A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade–Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5–8% less than calculation without considering parking activity. - Highlights: • We applied real parking distribution data to estimate evaporative vapor generation. • We applied real hourly temperature data to estimate hourly incremental vapor generation rate. • Evaporative emission for Florence is estimated based on parking distribution and hourly rate. - A new approach is proposed to quantify the weighted evaporative vapor generation based on parking distribution with an hourly incremental vapor generation rate

Evaporators

DEFF Research Database (Denmark)

Knudsen, Hans Jørgen Høgaard

1996-01-01

Type of evaporators. Regulation. Thermal dimensioning. Determination of pressure loss and heat transfer coefficients.......Type of evaporators. Regulation. Thermal dimensioning. Determination of pressure loss and heat transfer coefficients....

From field evaporation to focused ion beams

International Nuclear Information System (INIS)

Forbes, R.G.

2004-01-01

Full text: This paper report various items of recent progress in the theory of field evaporation and the theory of the liquid-metal ion source. The research has, in part, been driven by a desire to find out how to reduce the beam-spot size in a focused ion beam machine, which is developing as a significant tool of nanotechnology. A major factor in determining beam spot size seems to be the behavior of the liquid-metal ion source (LMIS), and one route might be to reduce the minimum emission current of a LMIS, if this is possible. Theories of LMIS minimum emission current have been re-examined. Some progress has been made, but development of more accurate theory has been constrained by several factors, include the long-known limitations of the present theory of field evaporation (FEV). This, in turn, has stimulated a wider re-examination of FEV theory. As part of some general theoretical remarks, the following items of recent progress will be covered. Various results concerning the prediction of the field F e at which the activation energy Q for field evaporation is zero, including calculations in which vacuum electrostatic energy changes are taken into account, and another look at the views of Kingham and Tsong concerning escape charge-state. Some years ago, the following approximate formula was derived for the dependence of FEV activation energy on field F: Q=B(F e /F - 1) 2 . It has recently been possible to show that the parameter B can be estimated as B= βYΩ/8, where Y is Young's modulus, Ω is the atomic volume, and β is a correction factor of order. In the framework of the charge-draining mechanism, another look at how the activation-energy hump can be modelled, in order to predict/explain the conditions under which FEV becomes dominated by ion tunnelling rather than field evaporation. A review of the changes in LMIS theory that result from applying the equation of continuity to the metal/vacuum interface, including modifications to the theory of minimum

The spatial extent of polycyclic aromatic hydrocarbons emission in the Herbig star HD 179218

Science.gov (United States)

Taha, A. S.; Labadie, L.; Pantin, E.; Matter, A.; Alvarez, C.; Esquej, P.; Grellmann, R.; Rebolo, R.; Telesco, C.; Wolf, S.

2018-04-01

Aim. We investigate, in the mid-infrared, the spatial properties of the polycyclic aromatic hydrocarbons (PAHs) emission in the disk of HD 179218, an intermediate-mass Herbig star at 300 pc. Methods: We obtained mid-infrared images in the PAH-1, PAH-2 and Si-6 filters centered at 8.6, 11.3, and 12.5 μm, and N-band low-resolution spectra using CanariCam on the 10-m Gran Telescopio Canarias (GTC). We compared the point spread function (PSF) profiles measured in the PAH filters to the profile derived in the Si-6 filter, where the thermal continuum emission dominates. We performed radiative transfer modeling of the spectral energy distribution (SED) and produced synthetic images in the three filters to investigate different spatial scenarios. Results: Our data show that the disk emission is spatially resolved in the PAH-1 and PAH-2 filters, while unresolved in the Si-6 filter. Thanks to very good observing conditions, an average full width at half maximum (FWHM) of 0.232'', 0.280'' and 0.293'' is measured in the three filters, respectively. Gaussian disk fitting and quadratic subtraction of the science and calibrator PSFs suggests a lower-limit characteristic angular diameter of the emission of 100 mas, or 30 au. The photometric and spectroscopic results are compatible with previous findings. Our radiative transfer (RT) modeling of the continuum suggests that the resolved emission should result from PAH molecules on the disk atmosphere being UV-excited by the central star. Simple geometrical models of the PAH component compared to the underlying continuum point to a PAH emission uniformly extended out to the physical limits of the disk model. Furthermore, our RT best model of the continuum requires a negative exponent of the surface density power-law, in contrast with earlier modeling pointing to a positive exponent. Conclusions: We have spatially resolved - for the first time to our knowledge - the PAHs emission in the disk of HD 179218 and set constraints on its

The levels, variation characteristics, and sources of atmospheric non-methane hydrocarbon compounds during wintertime in Beijing, China

Science.gov (United States)

Liu, Chengtang; Ma, Zhuobiao; Mu, Yujing; Liu, Junfeng; Zhang, Chenglong; Zhang, Yuanyuan; Liu, Pengfei; Zhang, Hongxing

2017-09-01

Atmospheric non-methane hydrocarbon compounds (NMHCs) were measured at a sampling site in Beijing city from 15 December 2015 to 14 January 2016 to recognize their pollution levels, variation characteristics, and sources. We quantified 53 NMHCs, and the proportions of alkanes, alkenes, acetylene, and aromatics to the total NMHCs were 49.8-55.8, 21.5-24.7, 13.5-15.9, and 9.3-10.7 %, respectively. The variation trends in the NMHC concentrations were basically identical and exhibited remarkable fluctuation, which was mainly ascribed to the variation in meteorological conditions, especially wind speed. The diurnal variations in NMHCs on clear days exhibited two peaks during the morning and evening rush hours, whereas the rush hours' peaks diminished or even disappeared on the haze days, implying that the relative contribution of the vehicular emissions to atmospheric NMHCs depended on the pollution status. Two evident peaks of the propane / propene ratios appeared in the early morning before sun rise and at noontime on clear days, whereas only one peak occurred in the afternoon during the haze days, which were attributed to the relatively fast reactions of propene with OH, NO3, and O3. Based on the chemical kinetic equations, the daytime OH concentrations were calculated to be in the range of 3. 47 × 105-1. 04 × 106 molecules cm-3 on clear days and 6. 42 × 105-2. 35 × 106 molecules cm-3 on haze days. The nighttime NO3 concentrations were calculated to be in the range of 2. 82 × 109-4. 86 × 109 molecules cm-3 on clear days. The correlation coefficients of typical hydrocarbon pairs (benzene / toluene, o-xylene / m,p-xylene, isopentane / n-pentane, etc.) revealed that vehicular emissions and coal combustion were important sources for atmospheric NMHCs in Beijing during the wintertime. Five major emission sources for atmospheric NMHCs in Beijing during the wintertime were further identified by positive matrix factorization (PMF), including gasoline-related emissions

New approaches to the modelling of multi-component fuel droplet heating and evaporation

KAUST Repository

Sazhin, Sergei S

2015-02-25

The previously suggested quasi-discrete model for heating and evaporation of complex multi-component hydrocarbon fuel droplets is described. The dependence of density, viscosity, heat capacity and thermal conductivity of liquid components on carbon numbers n and temperatures is taken into account. The effects of temperature gradient and quasi-component diffusion inside droplets are taken into account. The analysis is based on the Effective Thermal Conductivity/Effective Diffusivity (ETC/ED) model. This model is applied to the analysis of Diesel and gasoline fuel droplet heating and evaporation. The components with relatively close n are replaced by quasi-components with properties calculated as average properties of the a priori defined groups of actual components. Thus the analysis of the heating and evaporation of droplets consisting of many components is replaced with the analysis of the heating and evaporation of droplets consisting of relatively few quasi-components. It is demonstrated that for Diesel and gasoline fuel droplets the predictions of the model based on five quasi-components are almost indistinguishable from the predictions of the model based on twenty quasi-components for Diesel fuel droplets and are very close to the predictions of the model based on thirteen quasi-components for gasoline fuel droplets. It is recommended that in the cases of both Diesel and gasoline spray combustion modelling, the analysis of droplet heating and evaporation is based on as little as five quasi-components.

Studies of emissions from oil fires

International Nuclear Information System (INIS)

Fingas, M.; Lambert, L.; Wang, Z.; Li, K.; Ackerman, F.; Goldthorp, M.

2001-01-01

The use of in situ burning as a cleanup method for oil spills on water has received limited acceptance despite the fact that the method has been tried for more than 30 years. This lack of acceptance is mainly due to a poor understanding about combustion products and the issues involving the combustibility of oil-on-water. This paper presents results of a collaborative effort of several agencies in the United States and Canada to extensively research the many facets of burning oil. More than 45 mesoscale burns were conducted to examine the various aspects of diesel and crude oil burning in-situ. Sampling and monitoring of these burns was conducted at downwind stations, upwind stations and in the smoke plumes. This research effort has resulted in data which has led to a broader acceptance of in-situ burning as a viable spill countermeasure alternative. However, the concern over atmospheric emissions is the biggest barrier to the widespread use of burning. Emissions include the smoke plume, particulate matter precipitation, combustion gases, unburned hydrocarbons, organic compounds and the residue soot left at the burning pool site. A complete analysis of the emissions was performed by measuring all of these components. Particulate samples were taken in the air and analyzed for polycyclic aromatic hydrocarbons (PAHs). PAHs were found to be lower in the soot than in the starting oil, but higher concentrations of the larger molecular PAHs were found in the soot and residue, particularly for diesel burns. In general, between 92 to 98 per cent of the PAHs were destroyed. Diesel fires were found to emit more particulate matter and have longer danger zones. Combustion gases were found to be below exposure level maximums. Volatile organic compounds emissions were extensive from the fires, but the levels were less than from an evaporating oil spill. This paper included several tables indicating the 140 compounds that were identified and quantified. Prediction equations were

Mixture of working fluids in ORC plants with pool boiler evaporator

International Nuclear Information System (INIS)

Rajabloo, Talieh; Iora, Paolo; Invernizzi, Costante

2016-01-01

Highlights: • We assess the feasibility of pool boiler in ORCs operating with mixture working fluids. • We consider hydrocarbon and siloxane mixtures for low and high temperature ORCs. • Plants with pool boiler show comparable performances to once through evaporator. - Abstract: Power generation using Organic Rankine Cycle was studied in this paper in case of both low and high temperature cycles, exploiting respectively a geothermal heat source available at 167 °C, and heat available at 300 °C from the combustion of biomass. In particular we assess the feasibility of employing mixture of working fluids, in the case of replacing the typical once-through (OT) evaporator with the pool boiler (PB) technology, typically adopted for pure fluids. The analysis evidenced that in general the OT evaporator shows a slightly improved cycle performance in comparison to the PB and it results in some cases advantageous with respect to the pure working fluid. For instance in case of low temperature cycle, the best thermodynamic performances are obtained with mixture of i-C_5 and 75% n-C_4 in case of OT evaporator, yielding a recovery efficiency higher than the case with pure i-C_5 (7.7 vs. 7.4%) given the relatively higher values of both the recovery factor and cycle efficiency. Implementation of PB did not affect the plant performance significantly which shows the feasibility of having PB with potentially easier control.

Biogeochemistry of Halogenated Hydrocarbons

Science.gov (United States)

Adriaens, P.; Gruden, C.; McCormick, M. L.

2003-12-01

Halogenated hydrocarbons originate from both natural and industrial sources. Whereas direct anthropogenic emissions to the atmosphere and biosphere are often easy to assess, particularly when they are tied to major industrial activities, the attribution of emissions to other human activities (e.g., biomass burning), diffuse sources (e.g., atmospheric discharge, run off), and natural production (e.g., soils, fungi, algae, microorganisms) are difficult to quantify. The widespread occurrence of both alkyl and aryl halides in groundwater, surface water, soils, and various trophic food chains, even those not affected by known point sources, suggests a substantial biogeochemical cycling of these compounds (Wania and Mackay, 1996; Adriaens et al., 1999; Gruden et al., 2003). The transport and reactive fate mechanisms controlling their reactivity are compounded by the differences in sources of alkyl-, aryl-, and complex organic halides, and the largely unknown impact of biogenic processes, such as enzymatically mediated halogenation of organic matter, fungal production of halogenated hydrocarbons, and microbial or abiotic transformation reactions (e.g., Asplund and Grimvall, 1991; Gribble, 1996; Watling and Harper, 1998; Oberg, 2002). The largest source may be the natural halogenation processes in the terrestrial environment, as the quantities detected often exceed the amount that can be explained by human activities in the surrounding areas ( Oberg, 1998). Since biogeochemical processes result in the distribution of a wide range of halogenated hydrocarbon profiles, altered chemical structures, and isomer distributions in natural systems, source apportionment (or environmental forensics) can often only be resolved using multivariate statistical methods (e.g., Goovaerts, 1998; Barabas et al., 2003; Murphy and Morrison, 2002).This chapter will describe the widespread occurrence of halogenated hydrocarbons, interpret their distribution and biogeochemical cycling in light of

Novel Photocatalytic Reactor Development for Removal of Hydrocarbons from Water

Directory of Open Access Journals (Sweden)

Morgan Adams

2008-01-01

Full Text Available Hydrocarbons contamination of the marine environment generated by the offshore oil and gas industry is generated from a number of sources including oil contaminated drill cuttings and produced waters. The removal of hydrocarbons from both these sources is one of the most significant challenges facing this sector as it moves towards zero emissions. The application of a number of techniques which have been used to successfully destroy hydrocarbons in produced water and waste water effluents has previously been reported. This paper reports the application of semiconductor photocatalysis as a final polishing step for the removal of hydrocarbons from two waste effluent sources. Two reactor concepts were considered: a simple flat plate immobilised film unit, and a new rotating drum photocatalytic reactor. Both units proved to be effective in removing residual hydrocarbons from the effluent with the drum reactor reducing the hydrocarbon content by 90% under 10 minutes.

The reformation of liquid hydrocarbons in an aqueous discharge reactor

KAUST Repository

Zhang, Xuming

2015-04-21

We present an aqueous discharge reactor for the reformation of liquid hydrocarbons. To increase a dielectric constant of a liquid medium, we added distilled water to iso-octane and n-dodecane. As expected, we found decreased discharge onset voltage and increased discharge power with increased water content. Results using optical emission spectroscopy identified OH radicals and O atoms as the predominant oxidative reactive species with the addition of water. Enriched CH radicals were also visualized, evidencing the existence of cascade carbon-carbon cleavage and dehydrogenation processes in the aqueous discharge. The gaseous product consisted primarily of hydrogen, carbon monoxide, and unsaturated hydrocarbons. The composition of the product was readily adjustable by varying the volume of water added, which demonstrated a significant difference in composition with respect to the tested liquid hydrocarbon. In this study, we found no presence of CO2 emissions or the contamination of the reactor by solid carbon deposition. These findings offer a new approach to the reforming processes of liquid hydrocarbons and provide a novel concept for the design of a practical and compact plasma reformer. © 2015 IOP Publishing Ltd.

Modeling of air toxics from hydrocarbon pool fires

International Nuclear Information System (INIS)

Harvey, K.A.; Aydil, M.L.; Barone, J.B.

1996-01-01

While there is guidance for estimating the radiation hazards of fires (ARCHIE), there is little guidance on modeling the dispersion of hazardous materials from fires. The objective of this paper is to provide a review of the methodology used for modeling the impacts of liquid hydrocarbon pool fires. The required input variables for modeling of hydrocarbon pool fires include emission strength, emission duration, and dispersion characteristics. Methods for predicting the products of combustion including the use of literature values, test data, and thermodynamic equilibrium calculations are discussed. The use of energy balances coupled to radiative heat transfer calculations are presented as a method for determining flame temperature. Fire modeling literature is reviewed in order to determine other source release variables such as mass burn rate and duration and flame geometry

Flash evaporator

OpenAIRE

1997-01-01

A device and method for flash evaporating a reagent includes an evaporation chamber that houses a dome on which evaporation occurs. The dome is solid and of high thermal conductivity and mass, and may be heated to a temperature sufficient to vaporize a specific reagent. The reagent is supplied from an external source to the dome through a nozzle, and may be supplied as a continuous stream, as a shower, and as discrete drops. A carrier gas may be introduced into the evaporation chamber and cre...

Development of emissions inventories for the Auto/Oil Air Quality Improvement Research Program

International Nuclear Information System (INIS)

Pollack, A.K.; Fieber, J.L.; Lauer, G.; Dunker, A.M.; Noda, A.M.; Schleyer, C.H.; Chock, D.P.; Hertz, M.; Metcalfe, J.E.

1992-01-01

The air quality effects of different reformulated gasolines, various other alternative fuels, and developments in automotive technologies are being studied as part of a joint research project conducted by a consortium of three domestic auto companies and fourteen petroleum companies. As part of the air quality modeling effort, emission inventories are being developed in a near-term year (1995), and 21 fuels in a long-term year (2005 or 2010). A distinctive feature of this effort is that these inventories are the first used in an air quality study that treat light duty vehicle emissions by operating mode as well as by class, and base the speciation characteristics of each operating mode on actual vehicle test results. This incorporates an unusual amount of detail on the relative importance of each of the three vehicle exhaust, two evaporative, and running loss operating modes, both in terms of overall mass emission amounts and in terms of the hydrocarbon speciation and ozone reactivity. This study also allows a better estimate of the relative importance of each vehicle class and technology type to an overall emission inventory, and of the differences in the effects of alternative fuels between vehicle technologies and classes. In addition, the role of mobile source emissions relative to other sources of emissions for both short-term and long-term emission projections, and across a wide geographic range is being assessed. This paper first describes the techniques used in developing these emission inventories, and then examines regional, temporal, and fuel/vehicle effects on emissions

Hydrocarbon source apportionment for the 1996 Paso del Norte Ozone Study.

Science.gov (United States)

Fujita, E M

2001-08-10

The 1996 Paso del Norte (PdN) ozone study was conducted to improve current understanding of the significant meteorological and air quality processes that lead to high concentrations of ozone in El Paso, Texas (USA) and Ciudad Juárez, Chihuahua (Mexico). Two-hour canister samples were collected five times daily at 05.00-07.00 h, 07.00-09.00 h, 09.00-11.00 h, 11.00-13.00 h, and 15.00-17.00 h MST during intensive study periods at one urban and one rural site on each side of the border. An automated gas chromatograph was operated at one site in central El Paso. Source profiles (the fractional chemical composition of emissions) from motor vehicles, gasoline, liquefied petroleum gas, and commercial natural gas were combined with source profiles from other studies for input to the Chemical Mass Balance (CMB) receptor model to apportion the measured non-methane hydrocarbons (NMHC) to sources. On-road vehicle emissions accounted for one-half to two-thirds of the NMHC in Ciudad Juárez and El Paso with the highest contributions occurring during the morning and afternoon commute periods. Emissions from diesel exhaust contributed approximately 2-3% of NMHC in Ciudad Juárez and less than 2% in El Paso. The average sum of liquid gasoline and gasoline vapor increased during the day in Ciudad Juárez from 2% at 06.00 h to approximately 12% at 16.00 h. Diurnal and day-of-the-week patterns in the liquid gasoline contributions are essentially identical to the corresponding patterns for motor vehicle exhaust, which suggest that a large fraction of the liquid gasoline contribution may be associated with tailpipe emissions rather than evaporative emissions from motor vehicles or industrial sources. Including the sum of the two sources put the upper limit for tailpipe contributions at 60-70% of NMHC.

Plasma-assisted co-evaporation of {beta}-indium sulfide thin films

Energy Technology Data Exchange (ETDEWEB)

Kosaraju, Sreenivas; Marino, Joseph A.; Harvey, John A.; Wolden, Colin A. [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States)

2006-05-05

This paper describes the development of plasma-assisted co-evaporation (PACE) for the formation of {beta}-In{sub 2}S{sub 3} thin films. Indium was supplied by conventional thermal evaporation, while the chalcogen gas precursor (H{sub 2}S) was activated using an inductively coupled plasma (ICP) source. Using a combination of optical emission spectroscopy and mass spectrometry it was shown that the ICP effectively dissociated H{sub 2}S, producing atomic sulfur. Transport modeling was used to quantify the flux distributions of the co-evaporated metal and the plasma-generated species impinging the substrate. Model predictions were validated by measurements of deposition rate and film properties. Substantial improvements in both materials utilization and substrate temperature reduction were realized with respect to conventional co-evaporation. {beta}-In{sub 2}S{sub 3} was formed as low as 100{sup o}C and it was observed that quality was a strong function of S/In ratio. The grain size decreased and the optical band gap increased as the substrate temperature was reduced. (author)

Characterization of the vadose zone above a shallow aquifer contaminated with gas condensate hydrocarbons

International Nuclear Information System (INIS)

Sublette, K.; Duncan, K.; Thoma, G.; Todd, T.

2002-01-01

A gas production site in the Denver Basin near Ft. Lupton, Colorado has leaked gas condensate hydrocarbons from an underground concrete tank used to store produced water. The leak has contaminated a shallow aquifer. Although the source of pollution has been removed, a plume of hydrocarbon contamination still remains for nearly 46 m from the original source. An extensive monitoring program was conducted in 1993 of the groundwater and saturated sediments. The objective was to determine if intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurred at the site at a rate that would support remediation. Geochemical indicators of hydrogen biodegradation by microorganisms in the saturated zone included oxygen depletion, increased alkalinity, sulfate depletion, methane production and Fe2+ production associated with hydrogen contamination. The presence of sulfate-reducing bacteria and methanogens was also much higher in the contaminated sediments. Degraded hydrocarbon metabolites were found in contaminated groundwater. An extensive characterization of the vadose zone was conducted in which the vadose zone was sample in increments of 15 cm from the surface to the water table at contaminated and non contaminated sites. The samples were tested for individual C3+ hydrocarbons, methane, CO2, total organic carbon, total inorganic carbon, and total petroleum hydrocarbons. The vadose zone consisted of an active and aerobic bioreactor fueled by condensate hydrocarbons transported into the unsaturated zone by evaporation of hydrocarbons at the water table. It was concluded that the unsaturated zone makes an important contribution to the natural attenuation of gas condensate hydrocarbons in the area. 17 refs., 2 tabs., 28 figs

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 P; Mansfield, Marc L; McKinley, Michael; Kenney, Donna; Evans, Jordan

2017-10-17

We measured fluxes of methane, nonmethane 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.

Organic pollutants in the coastal environment off San Diego, California. 2: Petrogenic and biogenic sources of aliphatic hydrocarbons

International Nuclear Information System (INIS)

Tran, K.; Yu, C.C.; Zeng, E.Y.

1997-01-01

The results from the measurements of aliphatic hydrocarbons suggest that hydrocarbons suggest that hydrocarbons in the Point Loma Wastewater Treatment Plant (PLWTP) effluents are mainly petroleum derived; those in the Tijuana River runoff have largely originated from terrestrial plants with visible petroleum contamination; and those in the sea surface microlayer, sediment traps, and sediments at various coastal locations off San Diego have mostly resulted from biogenic contributions with enhanced microbial products in the summer season. Rainfall in the winter season appeared to amplify the inputs from terrestrial higher plants to the coastal areas. The PLWTP discharged approximately 3.85 metric tons of n-alkanes (C 10 -C 35 ) in 1994, well below the level (136 metric tons) estimated in 1979. The input of aliphatic hydrocarbons from the Tijuana River was about 0.101 metric tons in 1994. Diffusion, solubilization, evaporation, and microbial degradation seemed partially responsible for the difference in the concentrations and compositions of aliphatic hydrocarbons in different sample media, although the relative importance of each mechanism cannot be readily discerned from the available data. The results from analyses of aliphatic hydrocarbon compositional indices are generally consistent with those of polycyclic aromatic hydrocarbons

4-Nitrophenol, 1-nitropyrene, and 9-nitroanthracene emissions in exhaust particles from diesel vehicles with different exhaust gas treatments

Science.gov (United States)

Inomata, Satoshi; Fushimi, Akihiro; Sato, Kei; Fujitani, Yuji; Yamada, Hiroyuki

2015-06-01

The dependence of nitro-organic compound emissions in automotive exhaust particles on the type of aftertreatment used was investigated. Three diesel vehicles with different aftertreatment systems (an oxidation catalyst, vehicle-DOC; a particulate matter and NOx reduction system, vehicle-DPNR; and a urea-based selective catalytic reduction system, vehicle-SCR) and a gasoline car with a three-way catalyst were tested. Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) and nitrophenols in the particles emitted were analyzed by thermal desorption gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The secondary production of nitro-organic compounds on the filters used to collect particles and the adsorption of gaseous nitro-organic compounds by the filters were evaluated. Emissions of 1-nitropyrene, 9-nitroanthracene, and 4-nitrophenol in the diesel exhaust particles were then quantified. The NOx reduction process in vehicle-DPNR appeared to remove nitro-hydrocarbons efficiently but not to remove nitro-oxygenated hydrocarbons efficiently. The nitro-PAH emission factors were lower for vehicle-DOC when it was not fitted with a catalyst than when it was fitted with a catalyst. The 4-nitrophenol emission factors were also lower for vehicle-DOC with a catalyst than vehicle-DOC without a catalyst, suggesting that the oxidation catalyst was a source of both nitro-PAHs and 4-nitrophenol. The time-resolved aerosol mass spectrometry data suggested that nitro-organic compounds are mainly produced when an engine is working under load. The presence of 4-nitrophenol in the particles was not confirmed statistically because of interference from gaseous 4-nitrophenol. Systematic errors in the estimated amounts of gaseous 1-nitropyrene and 9-nitroanthracene adsorbed onto the filters and the estimated amounts of volatile nitro-organic compounds that evaporated during sampling and during post-sampling conditioning could not be excluded. An analytical method

First day of an oil spill on the open sea: Early mass transfers of hydrocarbons to air and water

NARCIS (Netherlands)

Gros, J.; Nabi, D.; Würz, B.; Wick, L.Y.; Brussaard, C.P.D.; Huisman, J.; van der Meer, J.R.; Reddy, C.M.; Arey, J.S.

2014-01-01

During the first hours after release of petroleum at sea, crude oil hydrocarbons partition rapidly into air and water. However, limited information is available about very early evaporation and dissolution processes. We report on the composition of the oil slick during the first day after a

Evaluation of Partial Oxidation Reformer Emissions

Energy Technology Data Exchange (ETDEWEB)

Unnasch, Stefan; Fable, Scott; Waterland, Larry

2006-01-06

In this study, a gasoline fuel processor and an ethanol fuel processor were operated under conditions simulating both startup and normal operation. Emissions were measured before and after the AGB in order to quantify the effectiveness of the burner catalyst in controlling emissions. The emissions sampling system includes CEM for O2, CO2, CO, NOx, and THC. Also, integrated gas samples are collected in evacuated canisters for hydrocarbon speciation analysis via GC. This analysis yields the concentrations of the hydrocarbon species required for the California NMOG calculation. The PM concentration in the anode burner exhaust was measured through the placement of a filter in the exhaust stream. The emissions from vehicles with fully developed on board reformer systems were estimated.

Modelling and Evaluation of Aircraft Emissions. Final report

International Nuclear Information System (INIS)

Savola, M.

1996-01-01

An application was developed to calculate the emissions and fuel consumption of a jet and turboprop powered aircraft in Finnair's scheduled and charter traffic both globally and in the Finnish flight information regions. The emissions calculated are nitrogen oxides, unburnt hydrocarbons and carbon monoxide. The study is based on traffic statistics of one week taken from three scheduled periods in 1993. Each flight was studied by dividing the flight profile into sections. The flight profile data are based on aircraft manufacturers' manuals, and they serve as initial data for engine manufacturers' emission calculation programs. In addition, the study includes separate calculations on air traffic emissions at airports during the so-called LTO cycle. The fuel consumption calculated for individual flights is 419,395 tonnes globally, and 146,142 tonnes in the Finnish flight information regions. According to Finnair's statistics the global fuel consumption is 0.97-fold compared with the result given by the model. The results indicate that in 1993 the global nitrogen oxide emissions amounted to 5,934 tonnes, the unburnt hydrocarbon emissions totalled 496 tonnes and carbon monoxide emissions 1,664 tonnes. The corresponding emissions in the Finnish flight information regions were as follows: nitrogen oxides 2,105 tonnes, unburnt hydrocarbons 177 tonnes and carbon monoxide 693 tonnes. (orig.)

Determination of polycyclic aromatic hydrocarbons in deposited waste using GC-MSD. Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen in Deponiegut mittels GC-MSD

Energy Technology Data Exchange (ETDEWEB)

Treffert, U. (chemlab, Gesellschaft fuer Analytik und Umweltberatung mbH, Bensheim (Germany). Abt. ' ' Organische Analytik' ' ); Kolb, M. (Fachhochschule Aalen (Germany)); Stoerk, H. (chemlab, Gesellschaft fuer Analytik und Umweltberatung mbH, Bensheim (Germany))

1999-06-01

The articel describes an analysis method for the determination of 16 polycyclic aromatic hydrocarbons in deposited waste. The single steps are described very detailed: sample preparation by extraction, evaporation, flash-chromatography (Al[sub 2]O[sub 3]), quantitative analysis by GC-MSD. (SR)

AIRFORCE. Aircraft emissions and radiative forcing from emissions

Energy Technology Data Exchange (ETDEWEB)

Meijer, E.W.; Kelder, H.; Velthoven, P.F.J. van; Wauben, W.M.F. [Royal Netherlands Meteorological Inst., De Bilt (Netherlands); Beck, J.P.; Velders, G.J.M. [National Inst. of Public Health and the Environment, Bilthoven (Netherlands); Lelieveld, J.; Scheeren, B.A. [Institute of Marine and Atmospheric Research Utrecht (Netherlands)

1997-12-31

The Dutch AIRFORCE project focuses on the effects of subsonic aircraft emissions on the chemical composition of the atmosphere and subsequent radiative forcing. It includes measurements in the tropopause region and the modelling of exhaust plumes and large-scale effects. An aircraft exhaust plume model has been developed to study plume processes. The results of the plume model are used in the global transport chemistry model CTMK to determine large-scale effects of plume processes. Due to the efficient conversion of NO{sub x} into HNO{sub 3} inside aircraft exhaust plumes, a decrease of about 25% of the O{sub 3} perturbation was found in the NAFC at 200 hPa in July. Measurements of hydrocarbons revealed a dominant role of the anthropogenic continental emissions of light hydrocarbons in the tropopause region. (author) 20 refs.

AIRFORCE. Aircraft emissions and radiative forcing from emissions

Energy Technology Data Exchange (ETDEWEB)

Meijer, E W; Kelder, H; Velthoven, P F.J. van; Wauben, W M.F. [Royal Netherlands Meteorological Inst., De Bilt (Netherlands); Beck, J P; Velders, G J.M. [National Inst. of Public Health and the Environment, Bilthoven (Netherlands); Lelieveld, J; Scheeren, B A [Institute of Marine and Atmospheric Research Utrecht (Netherlands)

1998-12-31

The Dutch AIRFORCE project focuses on the effects of subsonic aircraft emissions on the chemical composition of the atmosphere and subsequent radiative forcing. It includes measurements in the tropopause region and the modelling of exhaust plumes and large-scale effects. An aircraft exhaust plume model has been developed to study plume processes. The results of the plume model are used in the global transport chemistry model CTMK to determine large-scale effects of plume processes. Due to the efficient conversion of NO{sub x} into HNO{sub 3} inside aircraft exhaust plumes, a decrease of about 25% of the O{sub 3} perturbation was found in the NAFC at 200 hPa in July. Measurements of hydrocarbons revealed a dominant role of the anthropogenic continental emissions of light hydrocarbons in the tropopause region. (author) 20 refs.

Study of various evaporation rates of the mixture of Alq{sub 3}: DCM in a single furnace crucible

Energy Technology Data Exchange (ETDEWEB)

Abedi, Zahra; Janghouri, Mohammad [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of); Mohajerani, Ezeddin, E-mail: e-mohajerani@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of); Alahbakhshi, Masoud; Azari, Amin [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of); Fallahi, Afsoon [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, 424 Hafez Avenue, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

2014-03-15

The emitting color for a new organic light emitting diode (OLED) structure is tuned by doping an appropriate amount of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) orange dye into tris-(8-hydroxyquinoline) aluminum (Alq{sub 3}) emissive layer. Here, the blend of Alq{sub 3}:DCM is deposited in a single furnace crucible by various evaporation rates. The electro-optical behavior of organic light emitting diode devices is greatly influenced by varying the Alq{sub 3}:DCM film composition. It is investigated that when the deposition rate increased from 0.6 to 5 Å/s, complete energy transfer occurred from Alq{sub 3} to DCM and Electroluminescence (EL) peak shifted to higher wavelength regions. The device with evaporation rate of 0.6 Å/s shows a luminance of 3532 cd/m{sup 2} and maximum efficiency of 0.82 cd/A at 20 V. These blends show excellent orange emission host–guest system properties with easier deposition rate control. -- Highlight: • We fabricated light emitting layer by dissolving dyes in common solvent followed by thermal evaporation of dyes. • Achieving orange emissions with a single furnace. • We investigated for the first time Alq{sub 3}:DCM evaporation rate by using single furnace.

Determination of the radionuclide release factor for an evaporator process using nondestructive assay

International Nuclear Information System (INIS)

Johnson, R.E.

1998-01-01

The 242-A Evaporator is the primary waste evaporator for the Hanford Site radioactive liquid waste stored in underground double-shell tanks. Low pressure evaporation is used to remove water from the waste, thus reducing the amount of tank space required for storage. The process produces a concentrated slurry, a process condensate, and an offgas. The offgas exhausts through two stages of high-efficiency particulate air (HEPA) filters before being discharged to the atmosphere 40 CFR 61 Subpart H requires assessment of the unfiltered exhaust to determine if continuous compliant sampling is required. Because potential (unfiltered) emissions are not measured, methods have been developed to estimate these emissions. One of the methods accepted by the Environmental Protection Agency is the measurement of the accumulation of radionuclides on the HEPA filters. Nondestructive assay (NDA) was selected for determining the accumulation on the HEPA filters. NDA was performed on the HEPA filters before and after a campaign in 1997. NDA results indicate that 2.1 E+4 becquerels of cesium-137 were accumulated on the primary HEPA 1700 filter during the campaign. The feed material processed in the campaign contained a total of 1.4 E+l6 Bq of cesium-137. The release factor for the evaporator process is 1.5 E-12. Based on this release factor, continuous compliant sampling is not required

A suggestion to assess spilled hydrocarbons as a greenhouse gas source

Energy Technology Data Exchange (ETDEWEB)

McAlexander, Benjamin L., E-mail: bmcalexander@trihydro.com

2014-11-15

Petroleum-contaminated site management typically counts destruction of hydrocarbons by either natural or engineered processes as a beneficial component of remediation. While such oxidation of spilled hydrocarbons is often necessary for achieving risk reduction for nearby human and ecological receptors, site assessments tend to neglect that this also means that the pollutants are converted to greenhouse gases and emitted to the atmosphere. This article presents a suggestion that the current and long term greenhouse gas emissions from spilled hydrocarbons be incorporated to petroleum site assessments. This would provide a more complete picture of pollutant effects that could then be incorporated to remedial objectives. At some sites, this additional information may affect remedy selection. Possible examples include a shift in emphasis to remedial technologies that reduce pollutant greenhouse gas effects (e.g., by conversion of methane to carbon dioxide in the subsurface), and a more holistic context for considering remedial technologies with low emission footprints.

Evaporation and alignment of 1-undecene functionalised nanodiamonds

Energy Technology Data Exchange (ETDEWEB)

Astuti, Y.; Poolton, N.R.J.; Butenko, Y.V.; Šiller, L., E-mail: lidija.siller@ncl.ac.uk

2014-12-15

The possibility to align diamond nanoparticles has a number of potential technological applications, but there are few methods by which this can be achieved, and research in this field can be considered to be in its infancy. Hitherto, two methods which have been commonly used are lithography and chemical vapour deposition (CVD), but these methods are both complex and have poor effectiveness. In this paper, we present a new technique for particle alignment, which is simpler and avoids particle structural damage. The method works by functionalising the nanodiamonds of size 5 nm by attaching 1-undecene onto the nanodiamond surfaces; the particles are then evaporated using UHV and deposited onto TEM grids and mica surfaces at 200 °C. XPS, SERS, HRTEM, luminescence spectroscopy and luminescence micro-imaging have been applied to characterise samples both before and after evaporation. Deposition of nanodiamond onto a mica surface resulted in particle alignment with length scales of 500 µm. The XPS and Raman spectra confirmed the absence of non-diamond carbon (sp{sup 2}-hybridized carbon). Moreover, photoluminescence (emitting in the range of 2.48–1.55 eV; 500–800 nm) which is characteristic for nanodiamond with size of 5 nm was also observed, both before and after evaporation of the functionalised nanodiamonds. - Highlights: • 1-Undecene funcionalised nanodiamonds can be evaporated in vacuum. • When evaporated on mica surface the particles form line ∼500 μm in length. • Their luminescence emission is observed at 2.48–1.55 eV (500–800 nm)

Evaporation and alignment of 1-undecene functionalised nanodiamonds

International Nuclear Information System (INIS)

Astuti, Y.; Poolton, N.R.J.; Butenko, Y.V.; Šiller, L.

2014-01-01

The possibility to align diamond nanoparticles has a number of potential technological applications, but there are few methods by which this can be achieved, and research in this field can be considered to be in its infancy. Hitherto, two methods which have been commonly used are lithography and chemical vapour deposition (CVD), but these methods are both complex and have poor effectiveness. In this paper, we present a new technique for particle alignment, which is simpler and avoids particle structural damage. The method works by functionalising the nanodiamonds of size 5 nm by attaching 1-undecene onto the nanodiamond surfaces; the particles are then evaporated using UHV and deposited onto TEM grids and mica surfaces at 200 °C. XPS, SERS, HRTEM, luminescence spectroscopy and luminescence micro-imaging have been applied to characterise samples both before and after evaporation. Deposition of nanodiamond onto a mica surface resulted in particle alignment with length scales of 500 µm. The XPS and Raman spectra confirmed the absence of non-diamond carbon (sp 2 -hybridized carbon). Moreover, photoluminescence (emitting in the range of 2.48–1.55 eV; 500–800 nm) which is characteristic for nanodiamond with size of 5 nm was also observed, both before and after evaporation of the functionalised nanodiamonds. - Highlights: • 1-Undecene funcionalised nanodiamonds can be evaporated in vacuum. • When evaporated on mica surface the particles form line ∼500 μm in length. • Their luminescence emission is observed at 2.48–1.55 eV (500–800 nm)

Influence of in situ steam formation by radio frequency heating on thermodesorption of hydrocarbons from contaminated soil.

Science.gov (United States)

Roland, Ulf; Bergmann, Sabine; Holzer, Frank; Kopinke, Frank-Dieter

2010-12-15

Thermal desorption of a wide spectrum of organic contaminants, initiated by radio frequency (RF) heating, was studied at laboratory and pilot-plant scales for an artificially contaminated soil and for an originally contaminated soil from an industrial site. Up to 100 °C, moderate desorption rates were observed for light aromatics such as toluene, chlorobenzene, and ethylbenzene. Desorption of the less volatile contaminants was greatly enhanced above 100 °C, when fast evaporation of soil-water produced steam for hydrocarbon stripping (steam-distillation, desorption rates increased by more than 1 order of magnitude). For hydrocarbons with low water solubility (e.g., aliphatic hydrocarbons), the temperature increase above 100 °C after desiccation of soil again led to a significant increase of the removal rates, thus showing the impact of hydrocarbon partial pressure. RF heating was shown to be an appropriate option for thermally enhanced soil vapor extraction, leading to efficient cleaning of contaminated soils.

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

NARCIS (Netherlands)

Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

2013-01-01

The Amon mud volcano (MV), located at 1250m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the

Steady-state and transient hydrocarbon production in graphite by low energy impact of atomic and molecular deuterium projectiles

International Nuclear Information System (INIS)

Zhang, H.; Meyer, F.W.

2009-01-01

We report measurements of steady-state yields of methyl, methane and heavier hydrocarbons for deuterium atomic and molecular ions incident on ATJ graphite, HOPG, and a-C:D thin films in the energy range 10-200 eV/D. The yields were determined using a QMS technique in conjunction with calibrated hydrocarbon leaks. We have also studied transient hydrocarbon production and hydrogen (deuterium) re-emission for 80 and 150 eV/D D + , D 2 + , and D 3 + projectiles incident on ATJ graphite surfaces pre-loaded to steady state by 20 eV/D beams of the corresponding species. Immediately after starting the higher-energy beams, transient hydrocarbon and D 2 re-emission yields significantly larger than steady-state values were observed, which exponentially decayed as a function of beam fluence. The initial yield values were related to the starting hydrocarbon and deuterium densities in the prepared sample, while the exponential decay constants provided information on the hydrocarbon kinetic release and hydrogen (deuterium) detrapping cross-sections.

Luminescence of one dimensional ZnO, GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanostructure through thermal evaporation of Zn and Ge powder mixture

Energy Technology Data Exchange (ETDEWEB)

Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn; Kien, Vu Trung; Tam, Phuong Dinh; Huy, Pham Thanh

2016-07-15

Graphical abstract: - Highlights: • ZnO and GeO{sub 2}–ZnGeO{sub 4} nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture. • Morphology of specimens were observed to have a nanowire structure to rod-like morphology. • Strong NBE emission band with suppressed visible green emission band were observed on the dominant ZnO nanowires. • Strong emission of ∼530 nm were observed on the GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires. - Abstract: This paper reports the first attempt for fabrication of thermal evaporated Zn–Ge powder mixture to achieve near-band-edge (NBE) emission of ZnO and visible emission of GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires with controllable intensities. The nanowires were fabricated by thermal evaporation of Zn and Ge powder mixture, particularly, by using different Zn:Ge ratio, temperature and evaporated times. The morphology of nanowires was depended on the Zn and Ge ratio that was observed to have a nanowire structure to rod-like morphology. The thermal evaporation of Zn:Ge powder mixture resulted in formation of dominant ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires as a function of evaporated parameters. These results suggest that the application of thermal evaporation of Zn and Ge mixture for potential application in synthesis of ZnO or GeO{sub 2}–Zn{sub 2}GeO{sub 4} nanowires for optoelectronic field.

Evaporational losses under different soil moisture regimes and atmospheric evaporativities using tritium

International Nuclear Information System (INIS)

Saxena, P.; Chaudhary, T.N.; Mookerji, P.

1991-01-01

Tritium as tracer was used in a laboratory study to estimate the contribution of moisture from different soil depths towards actual soil water evaporation. Results indicated that for comparable amounts of free water evaporation (5 cm), contribution of moisture from 70-80 cm soil layer towards total soil moisture loss through evaporation increased nearly 1.5 to 3 folds for soils with water table at 90 cm than without water table. Identical initial soil moistures were exposed to different atmospheric evaporativities. Similarly, for a given initial soil moisture status, upward movement of moisture from 70-80 cm soil layer under low evaporativity was nearly 8 to 12 times that of under high evaporativity at 5 cm free water evaporation value. (author). 6 refs., 4 tabs., 2 figs

The evolution of hydrocarbons past the asymptotic giant branch: the case of MSX SMC 029

Science.gov (United States)

Pauly, Tyler; Sloan, Gregory C.; Kraemer, Kathleen E.; Bernard-Salas, Jeronimo; Lebouteiller, Vianney; Goes, Christopher; Barry, Donald

2015-01-01

We present an optimally extracted high-resolution spectrum of MSX SMC 029 obtained by the Infrared Spectrograph on the Spitzer Space Telescope. MSX SMC 029 is a carbon-rich object in the Small Magellanic Cloud that has evolved past the asymptotic giant branch (AGB). The spectrum reveals a cool carbon-rich dust continuum with emission from polycyclic aromatic hydrocarbons (PAHs) and absorption from simpler hydrocarbons, both aliphatic and aromatic, including acetylene and benzene. The spectrum shows many similarities to the carbon-rich post-AGB objects SMP LMC 011 in the Large Magellanic Cloud and AFGL 618 in the Galaxy. Both of these objects also show infrared absorption features from simple hydrocarbons. All three spectra lack strong atomic emission lines in the infrared, indicating that we are observing the evolution of carbon-rich dust and free hydrocarbons in objects between the AGB and planetary nebulae. These three objects give us a unique view of the elusive phase when hydrocarbons exist both as relatively simple molecules and the much more complex and ubiquitous PAHs. We may be witnessing the assembly of amorphous carbon into PAHs.

Impact of methanol and CNG fuels on motor-vehicle toxic emissions

International Nuclear Information System (INIS)

Black, F.; Gabele, P.

1991-01-01

The 1990 Clean Air Act Amendments require that the Environmental Protection Agency investigate the need for reduction of motor vehicle toxic emissions such as formaldehyde, acetaldehyde, benzene, 1,3-butadiene, and polycyclic organic matter. Toxic organic emissions can be reduced by utilizing the control technologies employed for regulated THC (NMHC) and CO emissions, and by changing fuel composition. The paper examines emissions associated with the use of methanol and compressed natural gas fuels. Both tailpipe and evaporative emissions are examined at varied ambient temperatures ranging from 20 C to 105 F. Tailpipe emissions are also examined over a variety of driving cycles with average speeds ranging from 7 to 48 mph. Results suggest that an equivalent ambient temperatures and average speeds, motor vehicle toxic emissions are generally reduced with methanol and compressed natural gas fuels relative to those with gasoline, except for formaldehyde emissions, which may be elevated. As with gasoline, tailpipe toxic emissions with methanol and compressed natural gas fuels generally increase when ambient temperature or average speed decreases (the sensitivity to these variables is greater with methanol than with compressed natural gas). Evaporative emissions generally increase when fuel volatility or ambient temperature increases (however, the relative contribution of evaporative sources to the aggregate toxic compound emissions is small)

METEV: Measurement Technologies for Emissions from Ethanol Fuelled Vehicles

Energy Technology Data Exchange (ETDEWEB)

Sandtroem-Dahl, Charlotte

2009-11-15

The interest of using alcohols, and especially ethanol, as vehicle fuel is high in Sweden. The advantages are many, such as; being renewable, the ethanol can be produced locally and it is easily mixed with gasoline. Alcohol fuels are considered to be a substantial part of the alternative fuel market, especially in Brazil, USA and Sweden. With this growing interest it is of most importance to investigate the emission performance of vehicles fuelled with alcohols. The focus in this study is on measurement and calculation of hydrocarbon emissions. The emission regulations in different countries have different ways to treat alcohol fuelled vehicles. When alcohols are used as blending components in gasoline, uncombusted alcohols from the fuel are emitted in the exhaust in various amounts. If a Flame Ionization Detector (FID) is used to measure hydrocarbons, the uncombusted alcohol will be included in the measurement. The alcohol is, per definition, however not a hydrocarbon (hydrocarbons contains only hydrogen and carbon). In the US regulations, the alcohol content is measured separately, and the FID measurement is adjusted for the alcohol part. This is not performed in the European regulations. The aim of this project is to highlight the need for a discussion regarding the methodology for measuring hydrocarbon and alcohol emissions from flexible fuelled vehicles operating on alcohol fuel blends.

Heat and mass transfer analogies for evaporation models at high evaporation rate

OpenAIRE

Trontin , P.; Villedieu , P.

2014-01-01

International audience; In the framework of anti and deicing applications, heated liquid films can appear above the ice thickness, or directly above the wall. Then, evaporation plays a major role in the Messinger balance and evaporated mass has to be predicted accurately. Unfortunately, it appears that existing models under-estimate evaporation at high temperature. In this study, different evaporation models at high evaporation rates are studied. The different hypothesis on which these models...

Emission and source characterization of monoaromatic hydrocarbons from coke production

Energy Technology Data Exchange (ETDEWEB)

He, Q.S.; Wang, X.M.; Sheng, G.Y.; Fu, J.M. [Chinese Academy of Sciences, Guangzhou (China). State Key Laboratory of Organic Geochemistry

2005-09-15

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.

[Emission and source characterization of monoaromatic hydrocarbons from coke production].

Science.gov (United States)

He, Qiu-Sheng; Wang, Xin-Ming; Sheng, Guo-Ying; Fu, Jia-Mo

2005-09-01

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.

Analysis of unregulated emissions from an off-road diesel engine during realistic work operations

Science.gov (United States)

Lindgren, Magnus; Arrhenius, Karine; Larsson, Gunnar; Bäfver, Linda; Arvidsson, Hans; Wetterberg, Christian; Hansson, Per-Anders; Rosell, Lars

2011-09-01

Emissions from vehicle diesel engines constitute a considerable share of anthropogenic emissions of pollutants, including many non-regulated compounds such as aromatic hydrocarbons and alkenes. One way to reduce these emissions might be to use fuels with low concentrations of aromatic hydrocarbons, such as Fischer-Tropsch (F-T) diesels. Therefore this study compared Swedish Environmental Class 1 diesel (EC1) with the F-T diesel fuel Ecopar™ in terms of emissions under varied conditions (steady state, controlled transients and realistic work operations) in order to identify factors influencing emissions in actual operation. Using F-T diesel reduced emissions of aromatic hydrocarbons, but not alkenes. Emissions were equally dependent on work operation character (load, engine speed, occurrence of transients) for both fuels. There were indications that the emissions originated from unburnt fuel, rather than from combustion products.

Removal of hydrocarbons from anode baking furnaces. Kombiniertes Abscheideverfahren fuer Kohlenwasserstoffe aus Anoden- und Elektrodenbrennoefen

Energy Technology Data Exchange (ETDEWEB)

Hajek, S.; Peukert, W.; Kaeppeler, G.

1993-10-01

Fumes from anode baking furnaces contain substantial concentrations of solid, liquid and gaseous hydrocarbons. Various concepts for fume treatment systems are discussed. A solution with indirect cooling with subsequent dry adsorption has various advantages in comparison to traditional systems with evaporative coolers. The adsorbents for collection of gaseous hydrocarbons originate from anode manufacturing so that no additives have to be fed into the process. The loaded adsorbents can be recycled into the process avoiding additional waste disposal. Pilot scale tests are necessary in order to determine the most important process variables. Results of the experiments show the possibilities and the physical-chemical limits of the used adsorbents in an integrated fume treatment. (orig.)

From evaporating pans to transpiring plants (John Dalton Medal Lecture)

Science.gov (United States)

Roderick, Michael

2013-04-01

The name of the original inventor of irrigated agriculture is lost to antiquity. Nevertheless, one can perhaps imagine an inquisitive desert inhabitant noting the greener vegetation along a watercourse and putting two and two together. Once water was being supplied and food was being produced it would be natural to ask a further question: how much water can we put on? No doubt much experience was gained down through the ages, but again, one can readily imagine someone inverting a rain gauge, filling it with water and measuring how fast the water evaporated. The inverted rain gauge measures the demand for water by the atmosphere. We call it the evaporative demand. I do not know if this is what actually happened but it sure makes an interesting start to a talk. Evaporation pans are basically inverted rain gauges. The rain gauge and evaporation pan measure the supply and demand respectively and these instruments are the workhorses of agricultural meteorology. Rain gauges are well known. Evaporation pans are lesser known but are in widespread use and are a key part of several national standardized meteorological networks. Many more pans are used for things like scheduling irrigation on farms or estimating evaporation from lakes. Analysis of the long records now available from standardized networks has revealed an interesting phenomenon, i.e., pan evaporation has increased in some places and decreased in other but when averaged over large numbers of pans there has been a steady decline. These independent reports from, for example, the US, Russia, China, India, Thailand, are replicated in the southern hemisphere in, for example, Australia, New Zealand and South Africa. One often hears the statement that because the earth is expected to warm with increasing greenhouse gas emissions then it follows that water will evaporate faster. The pan evaporation observations show that this widely held expectation is wrong. When expectations disagree with observations, it is the

Photo-assisted removal of fuel oil hydrocarbons from wood and concrete.

Science.gov (United States)

Popova, Inna E; Kozliak, Evguenii I

2008-08-01

A novel photo-treatment to decontaminate building structural elements polluted with fuel oil hydrocarbons as a result of spillage and/or a catastrophic flood was examined. A proof-of-concept study evaluating the photocatalytic removal of hydrocarbons (n-hexadecane and fuel oil #2) from contaminated wood (southern yellow pine) and concrete was conducted using scintillation counting (with (14)C-labeled n-hexadecane) and gas chromatography. Contaminated samples were irradiated by UV or fluorescent light in the absence or presence of a photocatalyst, TiO(2). As a result of the treatment, under various scenarios, up to 80-98% of the originally applied n-hexadecane was removed, within a wide range of contaminant concentrations (4-250 mg/g wood). The essential treatment time increased from 1-7 days for low concentrations to several weeks for high concentrations. Mass balance experiments showed that the only product formed from (14)C-labeled n-hexadecane in detectable amounts was (14)CO(2). For low amounts of applied hydrocarbon (4-20 mg/g wood), the overall process rate was limited by the contaminant transport/mobility whereas for high n-hexadecane concentrations (150-250 mg/g, corresponding to 50-80% filling of wood pores), the key factor was the photochemical reaction. Photodegradation experiments conducted with standard heating fuel oil #2 (a representative real-world contaminant) resulted in a significant (up to 80%) photochemical removal of mid-size hydrocarbons (C(13)-C(17)) in 3 weeks whereas heavier hydrocarbons (> C(17)) were not affected; light hydrocarbons (evaporation. These results point toward a promising technique to reclaim wooden and concrete structures contaminated with semi-volatile chemicals.

Final Rule for Control of Air Pollution From New Motor Vehicles and New Motor Vehicle Engines: Evaporative and Refueling Emission Regulations for Gasolineand Methanol-Fueled Light-Duty Vehicles and Light-Duty Trucks and Heavy-Duty Vehicles; Technical Amen

Science.gov (United States)

On March 24, 1993 EPA finalized a new test procedure to measure evaporative emissions from motor vehicles. The amendments modify several of the test procedure’s tolerances, equipment specifications, and procedural steps.

Y-Ba-Cu-O superconducting thin films by simultaneous or sequential evaporation

International Nuclear Information System (INIS)

Mogro-Campero, A.; Hunt, B.D.; Turner, L.G.; Burrell, M.C.; Balz, W.E.

1988-01-01

Superconducting thin films of Y-Ba-Cu-O near the 1:2:3 stoichiometry were produced by simultaneous (coevaporation) and sequential (multilayer) evaporation in the same evaporator. The best film obtained on yttria-stabilized zirconia (YSZ) had a superconducting onset temperature of 104 K, a midpoint T/sub c/ of 92 K, and zero resistance at T≤74 K. Stoichiometry was deduced by inductively coupled plasma emission spectroscopy, and elemental depth profiles were obtained by x-ray photoelectron spectroscopy. Film stoichiometry changes only near the film/substrate boundary for films on YSZ. Films on Si/SiO 2 were not superconducting; depth profiling shows severe changes of film composition with depth. A major theme of this work is process reproducibility, which was found to be poor for coevaporation but improved considerably for sequential evaporation

Evaporator Cleaning Studies

International Nuclear Information System (INIS)

Wilmarth, W.R.

1999-01-01

Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning

Mixed phase evaporation source

International Nuclear Information System (INIS)

1975-01-01

Apparatus for reducing convection current heat loss in electron beam evaporator is described. A material to be evaporated (evaporant) is placed in the crucible of an electron beam evaporation source along with a porous mass formed of a powdered or finely divided solid to act as an impedance to convection currents. A feed system is employed to replenish the supply of evaporant as it is vaporized

Evaporation channel as a tool to study fission dynamics

Science.gov (United States)

Di Nitto, A.; Vardaci, E.; La Rana, G.; Nadtochy, P. N.; Prete, G.

2018-03-01

The dynamics of the fission process is expected to affect the evaporation residue cross section because of the fission hindrance due to the nuclear viscosity. Systems of intermediate fissility constitute a suitable environment for testing such hypothesis since they are characterized by evaporation residue cross sections comparable or larger than the fission ones. Observables related to emitted charged particles, due to their relatively high emission probability, can be used to put stringent constraints on models describing the excited nucleus decay and to recognize the effects of fission dynamics. In this work model simulations are compared with the experimental data collected via the 32S +100 Mo reaction at Elab = 200 MeV. Consequently we pointed out, exploring an extended set of evaporation channel observables, the limits of the statistical model and the large improvement obtained with a dynamical model. Moreover we stress the importance of using an apparatus covering a large fraction of 4π to extract observables. Finally, we discuss the opportunity to measure more sensitive observables by a new detection device in operation at LNL.

Process control with optical emission spectroscopy in triode ion plating

International Nuclear Information System (INIS)

Salmenoja, K.; Korhonen, A.S.; Sulonen, M.S.

1985-01-01

Physical vapor deposition (PVD) techniques used to prepare, e.g., hard TiN, HfN, or ZrN coatings include a great variety of processes ranging from reactive evaporation to sputtering and ion plating. In ion plating one effective way to enhance ionization is to use a negatively biased hot filament. The use of an electron emitting filament brings an extra variable to be taken into account in developing the process control. In addition, proper control of the evaporation source is critical in ensuring reproducible results. With optical emission spectroscopy (OES) it should be possible to control the coating process more accurately. The stoichiometry and the composition of the growing coating may then be ensured effectively in subsequent runs. In this work the application of optical emission spectroscopy for process control in triode ion plating is discussed. The composition of the growing coating is determined experimentally using the relative intensities of specific emission lines. Changes in the evaporation rate and the gas flow can be seen directly from emission line intensities. Even the so-called poisoning of the evaporation source with reactive gas can be detected. Several experimental runs were carried out and afterwards the concentration profiles of the deposited coatings were checked with the nuclear resonance broadening (NRB) method. The results show the usefulness of emission spectroscopy in discharge control

Emissions from laboratory combustor tests of manufactured wood products

Energy Technology Data Exchange (ETDEWEB)

Wilkening, R.; Evans, M.; Ragland, K. [Univ. of Wisconsin, Madison, WI (United States); Baker, A. [USDA Forest Products Lab., Madison, WI (United States)

1993-12-31

Manufactured wood products contain wood, wood fiber, and materials added during manufacture of the product. Manufacturing residues and the used products are burned in a furnace or boiler instead of landfilling. Emissions from combustion of these products contain additional compounds from the combustion of non-wood material which have not been adequately characterized to specify the best combustion conditions, emissions control equipment, and disposal procedures. Total hydrocarbons, formaldehyde, higher aldehydes and carbon monoxide emissions from aspen flakeboard and aspen cubes were measured in a 76 mm i.d. by 1.5 m long fixed bed combustor as a function of excess oxygen, and temperature. Emissions of hydrocarbons, aldehydes and CO from flakeboard and from clean aspen were very sensitive to average combustor temperature and excess oxygen. Hydrocarbon and aldehyde emissions below 10 ppM were achieved with 5% excess oxygen and 1,200{degrees}C average temperature for aspen flakeboard and 1,100{degrees}C for clean aspen at a 0.9 s residence time. When the average temperature decreased below these levels, the emissions increased rapidly. For example, at 950{degrees}C and 5% excess oxygen the formaldehyde emissions were over 1,000 ppM. These laboratory tests reinforce the need to carefully control the temperature and excess oxygen in full-scale wood combustors.

Probing the Evaporation Dynamics of Ethanol/Gasoline Biofuel Blends Using Single Droplet Manipulation Techniques.

Science.gov (United States)

Corsetti, Stella; Miles, Rachael E H; McDonald, Craig; Belotti, Yuri; Reid, Jonathan P; Kiefer, Johannes; McGloin, David

2015-12-24

Using blends of bioethanol and gasoline as automotive fuel leads to a net decrease in the production of harmful emission compared to the use of pure fossil fuel. However, fuel droplet evaporation dynamics change depending on the mixing ratio. Here we use single particle manipulation techniques to study the evaporation dynamics of ethanol/gasoline blend microdroplets. The use of an electrodynamic balance enables measurements of the evaporation of individual droplets in a controlled environment, while optical tweezers facilitate studies of the behavior of droplets inside a spray. Hence, the combination of both methods is perfectly suited to obtain a complete picture of the evaporation process. The influence of adding varied amounts of ethanol to gasoline is investigated, and we observe that droplets with a greater fraction of ethanol take longer to evaporate. Furthermore, we find that our methods are sensitive enough to observe the presence of trace amounts of water in the droplets. A theoretical model, predicting the evaporation of ethanol and gasoline droplets in dry nitrogen gas, is used to explain the experimental results. Also a theoretical estimation of the saturation of the environment, with other aerosols, in the tweezers is carried out.

Hydrocarbon control strategies for gasoline marketing operations

Energy Technology Data Exchange (ETDEWEB)

Norton, R.L.; Sakaida, R.R.; Yamada, M.M.

1978-05-01

This informational document provides basic and current descriptions of gasoline marketing operations and methods that are available to control hydrocarbon emissions from these operations. The three types of facilities that are described are terminals, bulk plants, and service stations. Operational and business trends are also discussed. The potential emissions from typical facilities, including transport trucks, are given. The operations which lead to emissions from these facilities include (1) gasoline storage, (2) gasoline loading at terminals and bulk plants, (3) gasoline delivery to bulk plants and service stations, and (4) the refueling of vehicles at service stations. Available and possible methods for controlling emissions are described with their estimated control efficiencies and costs. This report also includes a bibliography of references cited in the text, and supplementary sources of information.

Process for gasification of heavy hydrocarbons or salvaged oil. [German patent

Energy Technology Data Exchange (ETDEWEB)

Koch, C

1978-09-14

The invention refers to the separation of solids which are carried over during evaporation of salvaged oil (oil recovered from used oil or fat). They are removed by exposing the oil vapour to an acceleration of 500 g to 20,000g in a hot gas cyclone. Subsequently the cleaned gas is converted to fission gas in a fission gas generator using an air-water gas mixture and is taken to the combustion equipment. By this process salvaged oil and heavy hydrocarbons can be used for burning in Diesel engines without previous refining.

Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

Energy Technology Data Exchange (ETDEWEB)

Guillen, Donna Post [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2013-09-01

The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammable hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.

Identification of emission sources of particle-bound polycyclic aromatic hydrocarbons in the vicinity of the industrial zone of the city of Novi Sad

Directory of Open Access Journals (Sweden)

Jovčić Nataša S.

2013-01-01

Full Text Available Data on polycyclic aromatic hydrocarbons (PAHs in ambient air accessed at selected locations in the vicinity of the industrial zone of the city of Novi Sad, Serbia, have been presented and analyzed in order to determine seasonal and spatial variations and to identify emission sources of particle-bound PAHs. Previous studies have demonstrated that the major contributors of PAHs in urban areas are the emissions from vehicle exhaust, and emissions releases from industrial processes like aluminium production, creosote and wood preservation, waste incineration, cement manufacture, petrochemical and related industries, commercial heat/power production etc. The sampling campaigns have been conducted at three sampling sites, during the two 14-day periods. The first site was situated near industrial area, with a refinery, power plant and heavy-traffic road in the vicinity. The second site was located nearby the heavy traffic area, especially busy during the rush hour. The third site was residential district. Summer sampling period lasted from June 26th to July 10th 2008, while sampling of ambient air during the winter was undertaken from January 22nd to February 5th 2009. Eighty-four (84 air samples were collected using a high volume air sampler TCR Tecora H0649010/ECHO. 16 US EPA polycyclic aromatic hydrocarbons were determined in all samples using a gas chromatographer with a mass spectrometer as a detector (Shimatzu MDGC/GCMS-2010. The total average concentrations of PAHs ranged from 1.21 to 1.77 ng/m3 during the summer period and from 6.31 to 7.25 ng/m3 in the winter. Various techniques, including diagnostic ratio (DR and principal component analysis (PCA, have been used to define and evaluate potential emission sources of PAHs. Diagnostic ratio analysis indicated that vehicles, diesel or/and gasoline, industrial and combustion emissions were sources of PAHs in the vicinity of the industrial zone. Additionally, principal component analysis was used

Forest evaporation models: Relationships between stand growth and evaporation

CSIR Research Space (South Africa)

Le Maitre, David C

1997-06-01

Full Text Available The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation...

Experimental and theoretical investigation of an evaporative fuel system for heat engines

International Nuclear Information System (INIS)

Thern, Marcus; Lindquist, Torbjoern; Torisson, Tord

2007-01-01

The evaporative gas turbine (EvGT) pilot plant has been in operation at Lund University in Sweden since 1997. This project has led to improved knowledge of evaporative techniques and the concept of introducing fuel into gas turbines by evaporation. This results in, amongst others, power augmentation, efficiency increase and lower emissions. This article presents the experimental and theoretical results of the evaporation of a mixture of ethanol and water into an air stream at elevated pressures and temperatures. A theoretical model has been established for the simultaneous heat and mass transfer occurring in the ethanol humidification tower. The theoretical model has been validated through experiments at several operating conditions. It has been shown that the air, water and ethanol can be calculated throughout the column in a satisfactory way. The height of the column can be estimated within an error of 15% compared with measurements. The results from the model are most sensitive to the properties of diffusion coefficient, viscosity, thermal conductivity and activity coefficient due to the complexity of the polar gas mixture of water and air

Review of Heterogeneous Catalysts for Catalytically Upgrading Vegetable Oils into Hydrocarbon Biofuels

OpenAIRE

Xianhui Zhao; Lin Wei; Shouyun Cheng; James Julson

2017-01-01

To address the issues of greenhouse gas emissions associated with fossil fuels, vegetable oilseeds, especially non-food oilseeds, are used as an alternative fuel resource. Vegetable oil derived from these oilseeds can be upgraded into hydrocarbon biofuel. Catalytic cracking and hydroprocessing are two of the most promising pathways for converting vegetable oil to hydrocarbon biofuel. Heterogeneous catalysts play a critical role in those processes. The present review summarizes current progres...

Evaporative cooling: Effective latent heat of evaporation in relation to evaporation distance from the skin

NARCIS (Netherlands)

Havenith, G.; Bröde, P.; Hartog, E.A. den; Kuklane, K.; Holmer, I.; Rossi, R.M.; Richards, M.; Farnworth, B.; Wang, X.

2013-01-01

Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has

The PAH Emission Characteristics of the Reflection Nebula NGC 2023

International Nuclear Information System (INIS)

Peeters, Els; Bauschlicher, Charles W. Jr.; Allamandola, Louis J.; Tielens, Alexander G. G. M.; Ricca, Alessandra; Wolfire, Mark G.

2017-01-01

We present 5–20 μ m spectral maps of the reflection nebula NGC 2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope, which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C 60 , and H 2 superposed on a dust continuum. We show that several PAH emission bands correlate with each other and exhibit distinct spatial distributions that reveal a spatial sequence with distance from the illuminating star. We explore the distinct morphology of the 6.2, 7.7, and 8.6 μ m PAH bands and find that at least two spatially distinct components contribute to the 7–9 μ m PAH emission in NGC 2023. We report that the PAH features behave independently of the underlying plateaus. We present spectra of compact, oval PAHs ranging in size from C 66 to C 210 , determined computationally using density functional theory, and we investigate trends in the band positions and relative intensities as a function of PAH size, charge, and geometry. Based on the NASA Ames PAH database, we discuss the 7–9 μ m components in terms of band assignments and relative intensities. We assign the plateau emission to very small grains with possible contributions from PAH clusters and identify components in the 7–9 μ m emission that likely originate in these structures. Based on the assignments and the observed spatial sequence, we discuss the photochemical evolution of the interstellar PAH family as the PAHs are more and more exposed to the radiation field of the central star in the evaporative flows associated with the Photo-Dissociation Regions in NGC 2023.

The PAH Emission Characteristics of the Reflection Nebula NGC 2023

Energy Technology Data Exchange (ETDEWEB)

Peeters, Els [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Allamandola, Louis J. [NASA Ames Research Center, Space Science Division, Mail Stop 245-6, Moffett Field, CA 94035 (United States); Tielens, Alexander G. G. M. [Leiden Observatory, P.O. Box 9513, 2300 RA Leiden (Netherlands); Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 N. Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Wolfire, Mark G., E-mail: epeeters@uwo.ca [Astronomy Department, University of Maryland, College Park, MD 20742 (United States)

2017-02-20

We present 5–20 μ m spectral maps of the reflection nebula NGC 2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope, which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C{sub 60}, and H{sub 2} superposed on a dust continuum. We show that several PAH emission bands correlate with each other and exhibit distinct spatial distributions that reveal a spatial sequence with distance from the illuminating star. We explore the distinct morphology of the 6.2, 7.7, and 8.6 μ m PAH bands and find that at least two spatially distinct components contribute to the 7–9 μ m PAH emission in NGC 2023. We report that the PAH features behave independently of the underlying plateaus. We present spectra of compact, oval PAHs ranging in size from C{sub 66} to C{sub 210}, determined computationally using density functional theory, and we investigate trends in the band positions and relative intensities as a function of PAH size, charge, and geometry. Based on the NASA Ames PAH database, we discuss the 7–9 μ m components in terms of band assignments and relative intensities. We assign the plateau emission to very small grains with possible contributions from PAH clusters and identify components in the 7–9 μ m emission that likely originate in these structures. Based on the assignments and the observed spatial sequence, we discuss the photochemical evolution of the interstellar PAH family as the PAHs are more and more exposed to the radiation field of the central star in the evaporative flows associated with the Photo-Dissociation Regions in NGC 2023.

Introducing ultrasonic falling film evaporator for moderate temperature evaporation enhancement.

Science.gov (United States)

Dehbani, Maryam; Rahimi, Masoud

2018-04-01

In the present study, Ultrasonic Falling Film (USFF), as a novel technique has been proposed to increase the evaporation rate of moderate temperature liquid film. It is a proper method for some applications which cannot be performed at high temperature, such as foodstuff industry, due to their sensitivity to high temperatures. Evaporation rate of sodium chloride solution from an USFF on an inclined flat plate compared to that for Falling Film without ultrasonic irradiation (FF) at various temperatures was investigated. The results revealed that produced cavitation bubbles have different effects on evaporation rate at different temperatures. At lower temperatures, size fluctuation and collapse of bubbles and in consequence induced physical effects of cavitation bubbles resulted in more turbulency and evaporation rate enhancement. At higher temperatures, the behavior was different. Numerous created bubbles joined together and cover the plate surface, so not only decreased the ultrasound vibrations but also reduced the evaporation rate in comparison with FF. The highest evaporation rate enhancement of 353% was obtained at 40 °C at the lowest Reynolds number of 250. In addition, the results reveal that at temperature of 40 °C, USFF has the highest efficiency compared to FF. Copyright © 2017 Elsevier B.V. All rights reserved.

A method for producing a hydrocarbon resin

Energy Technology Data Exchange (ETDEWEB)

Tsachev, A B; Andonov, K S; Igliyev, S P

1980-11-25

Rock coal resin (KS), for instance, with a relative density of 1,150 to 1,190 kilograms per cubic meter, which contains 8 to 10 percent naphthaline, 1.5 to 2.8 percent phenol and 6 to 15 percent substances insoluble in toluene, or its mixture with rock coal or oil fractions of resin are subjected to distillation (Ds) in a pipe furnace with two evaporators (Is) and a distillation tower with a temperature mode in the second stage of 320 to 360 degrees and 290 to 340 degrees in the pitch compartment. A hydrocarbon resin is produced with a high carbon content, especially for the production of resin and dolomite refractory materials, as well as fuel mixtures for blast furnace and open hearth industry.

Geographic variations in female breast cancer incidence in relation to ambient air emissions of polycyclic aromatic hydrocarbons.

Science.gov (United States)

Large, Courtney; Wei, Yudan

2017-07-01

A significant geographic variation of breast cancer incidence exists, with incidence rates being much higher in industrialized regions. The objective of the current study was to assess the role of environmental factors such as exposure to ambient air pollution, specifically carcinogenic polycyclic aromatic hydrocarbons (PAHs) that may be playing in the geographic variations in breast cancer incidence. Female breast cancer incidence and ambient air emissions of PAHs were examined in the northeastern and southeastern regions of the USA by analyzing data from the Surveillance, Epidemiology, and End Results (SEER) Program and the State Cancer Profiles of the National Cancer Institute and from the Environmental Protection Agency. Linear regression analysis was conducted to evaluate the association between PAH emissions and breast cancer incidence in unadjusted and adjusted models. Significantly higher age-adjusted incidence rates of female breast cancer were seen in northeastern SEER regions, when compared to southeastern regions, during the years of 2000-2012. After adjusting for potential confounders, emission densities of total PAHs and four carcinogenic individual PAHs (benzo[a]pyrene, dibenz[a,h]anthracene, naphthalene, and benzo[b]fluoranthene) showed a significantly positive association with annual incidence rates of breast cancer, with a β of 0.85 (p = 0.004), 58.37 (p = 0.010), 628.56 (p = 0.002), 0.44 (p = 0.041), and 77.68 (p = 0.002), respectively, among the northeastern and southeastern states. This study suggests a potential relationship between ambient air emissions of carcinogenic PAHs and geographic variations of female breast cancer incidence in the northeastern and southeastern US. Further investigations are needed to explore these interactions and elucidate the role of PAHs in regional variations of breast cancer incidence.

Characteristics of atmospheric non-methane hydrocarbons during high PM 10 episodes and normal days in Foshan, China

Science.gov (United States)

Guo, Songjun; Tan, Jihua; Ma, Yongliang; Yang, Fumo; Yu, Yongchan; Wang, Jiewen

2011-08-01

Atmospheric non-methane hydrocarbons (NMHCs) were firstly studied during high PM 10 episodes and normal days in December 2008 in Foshan, China. Ethyne, ethene, i-pentane, toluene, ethane and propane are six abundant hydrocarbons, accounting for round 80% of total NMHCs. Both diurnal variations and concentration ratios of morning (evening)/afternoon implied vehicular emission for most hydrocarbons. Correlation coefficients (R 2) of ethene, propene, i-butene, benzene, toluene and i-/n-butanes with ethyne were 0.60-0.88 (they were 0.64-0.88 during high PM 10 episode and 0.60-0.85 in normal days) except for ethene and i-butene in normal days, indicating these hydrocarbons are mainly related to vehicular emission. It suggests liquefied petroleum gas (LPG) and natural gas (NG) leakages are responsible for propane and ethane, respectively. The measured mean benzene/toluene (B/T) ratio (wt/wt) was 0.45 ± 0.29 during total sampling periods together with R 2 analysis, again indicating vehicular emission is main contributor to ambient hydrocarbons. And the lower B/T ratio (0.29 ± 0.11) during high PM 10 episodes than that (0.75 ± 0.29) in normal days is likely caused by air transport containing low B/T value (0.23) from Guangzhou as well as solvent application containing toluene in Foshan.

Vacuum evaporation of pure metals

OpenAIRE

Safarian, Jafar; Engh, Thorvald Abel

2013-01-01

Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision...

Evaporation in hydrology and meteorology

OpenAIRE

Brandsma, T.

1990-01-01

In this paper the role of evaporation in hydrology and meteorology is discussed, with the emphasis on hydrology. The basic theory of evaporation is given and methods to determine evaporation are presented. Some applications of evaporation studies in literature are given in order to illustrate the theory. Further, special conditions in evaporation are considered, followed by a fotmulation of the difficulties in determining evaporation, The last part of the paper gives a short discussion about ...

40 CFR 1045.105 - What exhaust emission standards must my sterndrive/inboard engines meet?

Science.gov (United States)

2010-07-01

... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION... the fuel type on which the engines in the engine family are designed to operate. You must meet the numerical emission standards for hydrocarbons in this section based on the following types of hydrocarbon...

ANALYSIS OF REAL-TIME VEHICLE HYDROCARBON EMISSIONS DATA

Science.gov (United States)

The report gives results of analyses using real-time dynamometer test emissions data from 13 passenger cars to examine variations in emissions during different speeds or modes of travel. The resulting data provided a way to separately identify idle, cruise, acceleration, and dece...

Modeling comprehensive chemical composition of weathered oil following a marine spill to predict ozone and potential secondary aerosol formation and constrain transport pathways

Science.gov (United States)

Drozd, Greg T.; Worton, David R.; Aeppli, Christoph; Reddy, Christopher M.; Zhang, Haofei; Variano, Evan; Goldstein, Allen H.

2015-11-01

Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate-volatile and semivolatile compounds (IVOC, SVOC), which cause secondary organic aerosol (SOA) and ozone production. The Deepwater Horizon (DWH) disaster in the northern Gulf of Mexico during Spring/Summer of 2010 presented a unique opportunity to observe SOA production due to an oil spill. To better understand these observations, we conducted measurements and modeled oil evaporation utilizing unprecedented comprehensive composition measurements, achieved by gas chromatography with vacuum ultraviolet time of flight mass spectrometry (GC-VUV-HR-ToFMS). All hydrocarbons with 10-30 carbons were classified by degree of branching, number of cyclic rings, aromaticity, and molecular weight; these hydrocarbons comprise ˜70% of total oil mass. Such detailed and comprehensive characterization of DWH oil allowed bottom-up estimates of oil evaporation kinetics. We developed an evaporative model, using solely our composition measurements and thermodynamic data, that is in excellent agreement with published mass evaporation rates and our wind-tunnel measurements. Using this model, we determine surface slick samples are composed of oil with a distribution of evaporative ages and identify and characterize probable subsurface transport of oil.

Performance and Exhaust Emissions in a Natural-Gas Fueled Dual-Fuel Engine

Science.gov (United States)

Shioji, Masahiro; Ishiyama, Takuji; Ikegami, Makoto; Mitani, Shinichi; Shibata, Hiroaki

In order to establish the optimum fueling in a natural gas fueled dual fuel engine, experiments were done for some operational parameters on the engine performances and the exhaust emissions. The results show that the pilot fuel quantity should be increased and its injection timing should be advanced to suppress unburned hydrocarbon emission in the middle and low output range, while the quantity should be reduced and the timing retarded to avoid onset of knock at high loads. Unburned hydrocarbon emission and thermal efficiency are improved by avoiding too lean natural gas mixture by restricting intake charge air. However, the improvement is limited because the ignition of pilot fuel deteriorates with excessive throttling. It is concluded that an adequate combination of throttle control and equivalence ratio ensures low hydrocarbon emission and the thermal efficiency comparable to diesel operation.

On the link between potential evaporation and regional evaporation from a CBL perspective

Science.gov (United States)

Lhomme, J. P.; Guilioni, L.

2010-07-01

The relationship between potential evaporation and actual evaporation was first examined by Bouchet (Proc Berkeley Calif Symp IAHS Publ, 62:134-142, 1963) who considered potential evaporation as the consequence of regional evaporation due to atmospheric feedbacks. Using a heuristic approach, he derived a complementary relationship which, despite no real theoretical background, has proven to be very useful in interpreting many experimental data under various climatic conditions. Here, the relationship between actual and potential evaporation is reinterpreted in the context of the development of the convective boundary layer (CBL): first, with a closed-box approach, where the CBL has an impermeable lid; and then with an open system, where air is exchanged between the CBL and its external environment. By applying steady forcing to these systems, it is shown that an equilibrium state is reached, where potential evaporation has a specific equilibrium formulation as a function of two parameters: one representing large-scale advection and the other the feedback effect of regional evaporation on potential evaporation, i.e. a kind of “medium-scale advection”. It is also shown that the original form of Bouchet’s complementary relationship is not verified in the equilibrium state. This analysis leads us to propose a new and more rational approach of the relationship between potential and actual evaporation through the effective surface resistance of the region.

Source rock hydrocarbons. Present status

International Nuclear Information System (INIS)

Vially, R.; Maisonnier, G.; Rouaud, T.

2013-01-01

This report first presents the characteristics of conventional oil and gas system, and the classification of liquid and gaseous non conventional hydrocarbons, with the peculiar case of coal-bed methane. The authors then describe how source rock hydrocarbons are produced: production of shale oils and gases (horizontal drilling, hydraulic fracturing, exploitation) and of coal-bed methane and coal mine methane. In the next part, they address and discuss the environmental impact of source rock hydrocarbon production: installation footprint, water resource management, drilling fluids, fracturing fluids composition, toxicity and recycling, air pollution, induced seismicity, pollutions from other exploitation and production activities. They propose an overview of the exploitation and production of source rock gas, coal-bed gas and other non conventional gases in the world. They describe the current development and discuss their economic impacts: world oil context and trends in the USA, in Canada and other countries, impacts on the North American market, on the world oil industry, on refining industries, on the world oil balance. They analyse the economic impacts of non conventional gases: development potential, stakes for the world gas trade, consequence for gas prices, development opportunities for oil companies and for the transport sector, impact on CO 2 emissions, macro-economic impact in the case of the USA

EVAPORATION FORM OF ICE CRYSTALS IN SUBSATURATED AIR AND THEIR EVAPORATION MECHANISM

OpenAIRE

ゴンダ, タケヒコ; セイ, タダノリ; Takehiko, GONDA; Tadanori, SEI

1987-01-01

The evaporation form and the evaporation mechanism of dendritic ice crystals grown in air of 1.0×(10)^5 Pa and at water saturation and polyhedral ice crystals grown in air of 4.0×10 Pa and at relatively low supersaturation are studied. In the case of dendritic ice crystals, the evaporation preferentially occurs in the convex parts of the crystal surfaces and in minute secondary branches. On the other hand, in the case of polyhedral ice crystals, the evaporation preferentially occurs in the pa...

40 CFR 89.424 - Dilute emission sampling calculations.

Science.gov (United States)

2010-07-01

... dioxide equation: CO 2mass=Carbon dioxide emissions, in grams per test mode. Density CO 2=Density of...=Grams C in fuel per gram of fuel Where: HC mass=hydrocarbon emissions, in grams for the mode CO 2mass=carbon monoxide emissions, in grams for the mode CO 2mass=carbon dioxide emissions, in grams for the mode...

Light hydrocarbon emissions from African savanna burnings

International Nuclear Information System (INIS)

Bonsang, B.; Lambert, G.; Boissard, C.C.

1991-01-01

A study was undertaken in West Africa to determine the background mixing ratio of nonmethane hydrocarbons (NMHC) during the dry season and to measure the composition of savanna burnings. The experiment was conducted from 13 to 22 January 1989 in the experimental station located at the border of the tropical rainforest and savanna. Samples were collected during aircraft flights at 2,400 m in the free troposphere, at 400 m in the haze layer and in a smoke plume at 200 m altitude. Samples representing the ground-level evolution of the local background were collected at 10 m altitude. Fire samples were collected at a short distance from the fires during the intensive experiments. Results are presented in tables and indicate that the effect of NMHC produced by biomass burning on the tropospheric photochemistry is limited to a few species, namely, C 2 -C 4 alkenes

Evaporation and Climate Change

NARCIS (Netherlands)

Brandsma, T.

1993-01-01

In this article the influence of climate change on evaporation is discussed. The emphasis is on open water evaporation. Three methods for calculating evaporation are compared considering only changes in temperature and factors directly dependent on temperature. The Penman-method is used to

Convection-enhanced water evaporation

OpenAIRE

B. M. Weon; J. H. Je; C. Poulard

2011-01-01

Water vapor is lighter than air; this can enhance water evaporation by triggering vapor convection but there is little evidence. We directly visualize evaporation of nanoliter (2 to 700 nL) water droplets resting on silicon wafer in calm air using a high-resolution dual X-ray imaging method. Temporal evolutions of contact radius and contact angle reveal that evaporation rate linearly changes with surface area, indicating convective (instead of diffusive) evaporation in nanoliter water droplet...

Attempt to enrich of a new spontaneous fissioning nuclide by evaporation of natural brine

International Nuclear Information System (INIS)

Adamek, A.; Zhuravleva, E.L.; Constantinescu, M.; Constantinescu, o.; Chuburkov, Yu.T.

1983-01-01

The enrichment of the new spontaneous fissioning nuclide discovered in the Cheleken brine, was made by evaporation. The purpose of this work was the comparison of behaviour of the new spontaneous fissioning nuclide with that of the known elements in the formation processes of the high concentration brines. Spontaneous fission of the nuclide was measured by means of the counters for multiple emission of neutrons. It is shown that the new spontaneous fissioning nuclide was enriched as well as other trace elements (Hg, Tl, Bi and Pb) in a solution remained after the evaporation of the initial solution. The conclusion is drawn that from the sea water brines could be obtained by evaporation which are enriched in trace elements with an enrichment degree higher than the natural brines

Calculating the evaporated water flow in a wet cooling tower

International Nuclear Information System (INIS)

Grange, J.L.

1994-04-01

On a cooling tower, it is necessary to determine the evaporated water flow in order to estimate the water consumption with a good accuracy according to the atmospheric conditions, and in order to know the characteristics of the plume. The evaporated flow is small compared to the circulating flow. A direct measurement is very inaccurate and cannot be used. Only calculation can give a satisfactory valuation. The two usable theories are the Merkel's one in which there are some simplifying assumptions, and the Poppe's one which is more exact. Both theories are used in the numerical code TEFERI which has been developed and is run by Electricite de France. The results obtained by each method are compared and validated by measurements made in the hot air of a cooling tower. The consequences of each hypothesis of Merkel's theory are discussed. This theory does not give the liquid water content in the plume and it under-estimates the evaporated flow all the lower the ambient temperature is. On the other hand, the Poppe's method agrees very closely with the measurements as well for the evaporated flow than for the liquid water concentration. This method is used to establish the specific consumption curves of the great nuclear plants cooling towers as well as to calculate the emission of liquid water drops in the plumes. (author). 11 refs., 9 figs

Thermocatalytic CO2-Free Production of Hydrogen from Hydrocarbon Fuels

Energy Technology Data Exchange (ETDEWEB)

University of Central Florida

2004-01-30

The main objective of this project is the development of an economically viable thermocatalytic process for production of hydrogen and carbon from natural gas or other hydrocarbon fuels with minimal environmental impact. The three major technical goals of this project are: (1) to accomplish efficient production of hydrogen and carbon via sustainable catalytic decomposition of methane or other hydrocarbons using inexpensive and durable carbon catalysts, (2) to obviate the concurrent production of CO/CO{sub 2} byproducts and drastically reduce CO{sub 2} emissions from the process, and (3) to produce valuable carbon products in order to reduce the cost of hydrogen production The important feature of the process is that the reaction is catalyzed by carbon particulates produced in the process, so no external catalyst is required (except for the start-up operation). This results in the following advantages: (1) no CO/CO{sub 2} byproducts are generated during hydrocarbon decomposition stage, (2) no expensive catalysts are used in the process, (3) several valuable forms of carbon can be produced in the process depending on the process conditions (e.g., turbostratic carbon, pyrolytic graphite, spherical carbon particles, carbon filaments etc.), and (4) CO{sub 2} emissions could be drastically reduced (compared to conventional processes).

Feasibility study on reduction of gasoline emissions from oil depots and gasoline stations in Indonesia

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

A field survey was conducted of oil shipment depots in Java and Bali islands owned by Indonesia's state-run oil company to study measures for reduction in greenhouse effect gas emissions. Studies were made on the grasp of the amount of the hydrocarbon vapor emitted into the air, the amount of the gasoline recovered in case of adopting the vapor emission preventive technology, equipment cost/operational cost, etc. Concretely, the following three were studied: change of the gasoline storage tank to the inner floating roof type, and prevention of evaporation loss at the time of receiving and breathing loss caused by temperature changes; replacement with the vapor recovery type loading arm to recover gasoline vapor generated at the time of shipment/filling, and installation of the vapor recovery unit to recover vapor as gasoline; vapor balance system to recover in underground tank the gasoline vapor generated at the time of filling gasoline at gas station. As a result of the study, the recovered gasoline amount was 66,393 Kl/y and the CO2 reduction amount was 14,474 t/y at oil shipment depots and approximately 650 gasoline stations in Jakarta and Surabaya. (NEDO)

Production of hydrogen from hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Lohmueller, R

1984-03-01

Hydrocarbons are the preferred starting materials for the industrial production of hydrogen. Most hydrogen is produced by steam reforming of light hydrocarbons. Partial oxidation of heavy oil and residue is used for the production of H/sub 2/ and synthesis gas in large plants. In both cases gas purification was improved. Hydrogen-rich gases like coke oven gas, refinery-offgas, and offgases from the chemical and petrochemical industry have high potential for becoming a major source of hydrogen. Processes for recovering H/sub 2/ (and by-products) are condensation and rectification at low temperatures and, most attractive and versatile for the production of very pure H/sub 2/, adsorption (PSA). The environmental impact of H/sub 2/ production lies mainly in the emission of CO/sub 2/ and heat. Other forms of pollution can be considerably reduced by conventional methods. The economy of H/sub 2/ production depends essentially on price and availability of the raw materials.

Wintertime Emissions from Produced Water Ponds

Science.gov (United States)

Evans, J.; Lyman, S.; Mansfield, M. L.

2013-12-01

Every year oil and gas drilling in the U.S. generates billions of barrels of produced water (water brought to the surface during oil or gas production). Efficiently disposing of produced water presents a constant financial challenge for producers. The most noticeable disposal method in eastern Utah's Uintah Basin is the use of evaporation ponds. There are 427 acres of produced water ponds in the Uintah Basin, and these were used to evaporate more than 5 million barrels of produced water in 2012, 6% of all produced water in the Basin. Ozone concentrations exceeding EPA standards have been observed in the Uintah Basin during winter inversion conditions, with daily maximum 8 hour average concentrations at some research sites exceeding 150 parts per billion. Produced water contains ozone-forming volatile organic compounds (VOC) which escape into the atmosphere as the water is evaporated, potentially contributing to air quality problems. No peer-reviewed study of VOC emissions from produced water ponds has been reported, and filling this gap is essential for the development of accurate emissions inventories for the Uintah Basin and other air sheds with oil and gas production. Methane, carbon dioxide, and VOC emissions were measured at three separate pond facilities in the Uintah Basin in February and March of 2013 using a dynamic flux chamber. Pond emissions vary with meteorological conditions, so measurements of VOC emissions were collected during winter to obtain data relevant to periods of high ozone production. Much of the pond area at evaporation facilities was frozen during the study period, but areas that actively received water from trucks remained unfrozen. These areas accounted for 99.2% of total emissions but only 9.5% of the total pond area on average. Ice and snow on frozen ponds served as a cap, prohibiting VOC from being emitted into the atmosphere. Emissions of benzene, toluene, and other aromatic VOCs averaged over 150 mg m-2 h-1 from unfrozen pond

Importance of Rain Evaporation and Continental Convection in the Tropical Water Cycle

Science.gov (United States)

Worden, John; Noone, David; Bowman, Kevin; Beer, R.; Eldering, A.; Fisher, B.; Gunson, M.; Goldman, Aaron; Kulawik, S. S.; Lampel, Michael;

Polycyclic aromatic hydrocarbons as a tracer of star formation?

NARCIS (Netherlands)

Peeters, E; Spoon, HWW; Tielens, AGGM

2004-01-01

Infrared (IR) emission features at 3.3, 6.2, 7.7, 8.6, and 11.3 mum are generally attributed to IR fluorescence from ( mainly) far-ultraviolet (FUV) pumped large polycyclic aromatic hydrocarbon (PAH) molecules. As such, these features trace the FUV stellar flux and are thus a measure of star

Evaporation in hydrology and meteorology

NARCIS (Netherlands)

Brandsma, T.

1990-01-01

In this paper the role of evaporation in hydrology and meteorology is discussed, with the emphasis on hydrology. The basic theory of evaporation is given and methods to determine evaporation are presented. Some applications of evaporation studies in literature are given in order to illustrate the

Determination of polycyclic aromatic hydrocarbons in airborne

International Nuclear Information System (INIS)

Pachon Q, Jorge; Garcia L, Hector; Bustos L, Martha; Bravo A, Humberto; Sosa E, Rodolfo

2004-01-01

Rainfall polycyclic aromatic hydrocarbons (PAH) concentrations were determined in particulate matter with a <10 mm aerodynamic diameter (PM10) in three industrial municipalities of the metropolitan zone of Bogota City (MZBC). The 12 samples of greatest concentration of PM10 collected between 2001 and 2002 at the stations of atmospheric monitoring of Cundinamarca secretary of health (SSC), in the municipalities of Soacha, Sibate and Cajica, were analyzed. The results were correlated with emissions in the area, by means of emission factors and environmental agencies information. The particulate matter results for the analyzed period show concentrations that exceed the air quality standard of the US environmental protection agency EPA on several occasions at the Soacha municipality, whereas the air quality in the Sibate and Cajica municipalities did not show that to be the case. Despite the reduced number of samples and sampling sites, we believe that the reported profiles can be considered a valid estimation of the average air quality of the MZBC. The identified PAH species were: phenanthrene(Phe), anthracene(Ant), fluoranthene(Fla), pyrene(Pyr), benzo(a)anthracene (Baa), chrysene(chr), benzo(ghi)perylene(BgP) and indeno(1,2,3-cd)pyrene(Ind). It was not possible to quantify naphthalene (Nap), acenaphthy-lene(Acy), acenaphthene(Ace), nor fluorene(Flu), being light and volatile hydrocarbons with greater presence in the gaseous phase of the air. The correlation of PAH with source emissions shows mobile sources to be the main origin. The intervals of concentration of both individual PAH and the total species were similar to the ones usually found in other industrial zones of the world. PAHs correlations allowed pinpointing common emission sources between Soacha and Sibate municipalities

The levels, variation characteristics, and sources of atmospheric non-methane hydrocarbon compounds during wintertime in Beijing, China

Directory of Open Access Journals (Sweden)

C. Liu

2017-09-01

Full Text Available Atmospheric non-methane hydrocarbon compounds (NMHCs were measured at a sampling site in Beijing city from 15 December 2015 to 14 January 2016 to recognize their pollution levels, variation characteristics, and sources. We quantified 53 NMHCs, and the proportions of alkanes, alkenes, acetylene, and aromatics to the total NMHCs were 49.8–55.8, 21.5–24.7, 13.5–15.9, and 9.3–10.7 %, respectively. The variation trends in the NMHC concentrations were basically identical and exhibited remarkable fluctuation, which was mainly ascribed to the variation in meteorological conditions, especially wind speed. The diurnal variations in NMHCs on clear days exhibited two peaks during the morning and evening rush hours, whereas the rush hours' peaks diminished or even disappeared on the haze days, implying that the relative contribution of the vehicular emissions to atmospheric NMHCs depended on the pollution status. Two evident peaks of the propane ∕ propene ratios appeared in the early morning before sun rise and at noontime on clear days, whereas only one peak occurred in the afternoon during the haze days, which were attributed to the relatively fast reactions of propene with OH, NO3, and O3. Based on the chemical kinetic equations, the daytime OH concentrations were calculated to be in the range of 3. 47 × 105–1. 04 × 106 molecules cm−3 on clear days and 6. 42 × 105–2. 35 × 106 molecules cm−3 on haze days. The nighttime NO3 concentrations were calculated to be in the range of 2. 82 × 109–4. 86 × 109 molecules cm−3 on clear days. The correlation coefficients of typical hydrocarbon pairs (benzene ∕ toluene, o-xylene ∕ m,p-xylene, isopentane ∕ n-pentane, etc. revealed that vehicular emissions and coal combustion were important sources for atmospheric NMHCs in Beijing during the wintertime. Five major emission sources for atmospheric NMHCs in Beijing during

Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios

Energy Technology Data Exchange (ETDEWEB)

Yang, Tzu-Ting, E-mail: d89844001@ntu.edu.tw [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China); Lin, Shaw-Tao [Department of Applied Chemistry, Providence University, No. 200 Chung-Chi Rd., Salu Dist., Taichung City 43301, Taiwan (China); Lin, Tser-Sheng [Department of Safety, Health, and Environmental Engineering, National United University, 2 Lien Da, Maioli 360, Taiwan (China); Chung, Hua-Yi [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China)

2015-02-15

The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17–78.72 mg/g, 26,139.80–35,932.98 and 5735.22–13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26–83.70% and 16.30–29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82–797.76 ng/g) was approximately 6.92–25.08 times higher than that of the gaseous phase (26.27–36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO{sub 3}) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency. - Highlights: • PAHs emissions are influenced by mosquito coils containing various atomic H/C ratios. • The PAHs generated by burning mosquito coils mainly occur in the gaseous phase. • Total TEQ emission factors of PAHs mainly consisted of the particulate phase (> 87%). • The BaP and BaA accounted for 71.13–77.28% of the total TEQ emission factors. • Special PAH ratios were regarded as characteristic ratios for burning mosquito coil.

Ultraviolet Studies of Jupiter's Hydrocarbons and Aerosols from Galileo

Science.gov (United States)

Gladstone, G. Randall

2001-01-01

This is the final report for this project. The purpose of this project was to support PI Wayne Pryor's effort to reduce and analyze Galileo UVS (Ultraviolet Spectrometer) data under the JSDAP program. The spectral observations made by the Galileo UVS were to be analyzed to determine mixing ratios for important hydrocarbon species (and aerosols) in Jupiter's stratosphere as a function of location on Jupiter. Much of this work is still ongoing. To date, we have concentrated on analyzing the variability of the auroral emissions rather than the absorption signatures of hydrocarbons, although we have done some work in this area with related HST-STIS data.

Evaluation of malodor for automobile air conditioner evaporator by using laboratory-scale test cooling bench.

Science.gov (United States)

Kim, Kyung Hwan; Kim, Sun Hwa; Jung, Young Rim; Kim, Man Goo

2008-09-12

As one of the measures to improve the environment in an automobile, malodor caused by the automobile air-conditioning system evaporator was evaluated and analyzed using laboratory-scale test cooling bench. The odor was simulated with an evaporator test cooling bench equipped with an airflow controller, air temperature and relative humidity controller. To simulate the same odor characteristics that occur from automobiles, one previously used automobile air conditioner evaporator associated with unpleasant odors was selected. The odor was evaluated by trained panels and collected with aluminum polyester bags. Collected samples were analyzed by thermal desorption into a cryotrap and subsequent gas chromatographic separation, followed by simultaneous olfactometry, flame ionization detector and identified by atomic emission detection and mass spectrometry. Compounds such as alcohols, aldehydes, and organic acids were identified as responsible odor-active compounds. Gas chromatography/flame ionization detection/olfactometry combined sensory method with instrumental analysis was very effective as an odor evaluation method in an automobile air-conditioning system evaporator.

Negative ion emission at field electron emission from amorphous (alpha-C:H) carbon

CERN Document Server

Bernatskij, D P; Ivanov-Omskij, V I; Pavlov, V G; Zvonareva, T K

2001-01-01

The study on the electrons field emission from the plane cathode surface on the basis of the amorphous carbon film (alpha-C:H) is carried out. The methodology, making it possible to accomplish simultaneously the registration of the emission currents and visually observe the distribution of the emission centers on the plane emitter surface is developed. The analysis of the oscillograms indicated that apart from the proper electron constituent the negative ions of hydrogen (H sup - and H sub 2 sup -), carbon (C sup -) and hydrocarbon (CH sub n sup -) are observed. The ions emission is connected with the processes of formation and degradation of the local emission centers

Assessment of environmentally friendly fuel emissions from in-use vehicle exhaust: low-blend iso-stoichiometric GEM mixture as example.

Science.gov (United States)

Schifter, Isaac; Díaz-Gutiérrez, Luis; Rodríguez-Lara, René; González-Macías, Carmen; González-Macías, Uriel

2017-05-01

Gasoline-ethanol-methanol fuel blends were formulated with the same stoichiometric air-to-fuel ratio and volumetric energy concentration as any binary ethanol-gasoline blend. When the stoichiometric blends operated in a vehicle, the time period, injector voltage, and pressure for each fuel injection event in the engine corresponded to a given stoichiometric air-to-fuel ratio, and the load was essentially constant. Three low oxygen content iso-stoichiometric ternary gasoline-ethanol-methanol fuel blends were prepared, and the properties were compared with regular-type fuel without added oxygen. One of the ternary fuels was tested using a fleet of in-use vehicles for15 weeks and compared to neat gasoline without oxygenated compounds as a reference. Only a small number of publications have compared these ternary fuels in the same engine, and little data exist on the performance and emissions of in-use spark-ignition engines. The total hydrocarbon emissions observed was similar in both fuels, in addition to the calculated ozone forming potential of the tailpipe and evaporative emissions. In ozone non-attainment areas, the original purpose for oxygenate gasolines was to decrease carbon monoxide emissions. The results suggest that the strategy is less effective than expected because there still exist a great number of vehicles that have suffered the progressive deterioration of emissions and do not react to oxygenation, while new vehicles are equipped with sophisticated air/fuel control systems, and oxygenation does not improve combustion because the systems adjust the stoichiometric point, making it insensitive to the origin of the added excess oxygen (fuel or excess air). Graphical abstract Low level ternary blend of gasoline-ethanol-methanol were prepared with the same stoichiometric air-fuel ratio and volumetric energy concentration, based on the volumetric energy density of the pre-blended components. Exhaust and evaporative emissions was compared with a blend

Emission of oxygenated polycyclic aromatic hydrocarbons from biomass pellet burning in a modern burner for cooking in China

Science.gov (United States)

Shen, Guofeng; Wei, Siye; Zhang, Yanyan; Wang, Rong; Wang, Bin; Li, Wei; Shen, Huizhong; Huang, Ye; Chen, Yuanchen; Chen, Han; Wei, Wen; Tao, Shu

2012-12-01

Biomass pellets are undergoing fast deployment widely in the world, including China. To this stage, there were limited studies on the emissions of various organic pollutants from the burning of those pellets. In addition to parent polycyclic aromatic hydrocarbons, oxygenated PAHs (oPAHs) have been received increased concerns. In this study, emission factors of oPAHs (EFoPAHs) were measured for two types of pellets made from corn straw and pine wood, respectively. Two combustion modes with (mode II) and without (mode I) secondary side air supply in a modern pellet burner were investigated. For the purpose of comparison, EFoPAHs for raw fuels combusted in a traditional cooking stove were also measured. EFoPAHs were 348 ± 305 and 396 ± 387 μg kg-1 in the combustion mode II for pine wood and corn straw pellets, respectively. In mode I, measured EFoPAHs were 77.7 ± 49.4 and 189 ± 118 μg kg-1, respectively. EFs in mode II were higher (2-5 times) than those in mode I mainly due to the decreased combustion temperature under more excess air. Compared to EFoPAHs for raw corn straw and pine wood burned in a traditional cooking stove, total EFoPAHs for the pellets in mode I were significantly lower (p pellets burned in mode II was not statistically significant. Taking both the increased thermal efficiencies and decreased EFs into consideration, substantial reduction in oPAH emission can be expected if the biomass pellets can be extensively used by rural residents.

Characterizing Methane Emissions at Local Scales with a 20 Year Total Hydrocarbon Time Series, Imaging Spectrometry, and Web Facilitated Analysis

Science.gov (United States)

Bradley, Eliza Swan

Methane is an important greenhouse gas for which uncertainty in local emission strengths necessitates improved source characterizations. Although CH4 plume mapping did not motivate the NASA Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) design and municipal air quality monitoring stations were not intended for studying marine geological seepage, these assets have capabilities that can make them viable for studying concentrated (high flux, highly heterogeneous) CH4 sources, such as the Coal Oil Point (COP) seep field (˜0.015 Tg CH4 yr-1) offshore Santa Barbara, California. Hourly total hydrocarbon (THC) data, spanning 1990 to 2008 from an air pollution station located near COP, were analyzed and showed geologic CH4 emissions as the dominant local source. A band ratio approach was developed and applied to high glint AVIRIS data over COP, resulting in local-scale mapping of natural atmospheric CH4 plumes. A Cluster-Tuned Matched Filter (CTMF) technique was applied to Gulf of Mexico AVIRIS data to detect CH4 venting from offshore platforms. Review of 744 platform-centered CTMF subsets was facilitated through a flexible PHP-based web portal. This dissertation demonstrates the value of investigating municipal air quality data and imaging spectrometry for gathering insight into concentrated methane source emissions and highlights how flexible web-based solutions can help facilitate remote sensing research.

Emissions from co-combustion of wood and household refuse

International Nuclear Information System (INIS)

Zhang, X.J.; Peterson, F.

1996-01-01

An investigation was carried out on the emissions produced in a 20 kW experimental boiler burning a combination of wood and household refuse. The wood content ranged form 10 to 50%. Direct sampling with Tenax adsorbent was used to cover a range of volatile organic compounds (VOCs). The measurements also included unburned hydrocarbons, carbon monoxide, carbon dioxide, oxygen and flue gas temperature. Combustion and emission parameters were recorded continuously with a multi-point data logger. VOCs were analyzed by gas chromatography and mass spectrometer (GC/MS). The main emphasis was placed on the effect of wood on VOC emissions. The results showed that as the wood content increased from 10 to 50%, there was a roughly linear increase in emissions of total VOCs. Carbon monoxide and unburned hydrocarbon emissions also increased. These results suggest that household refuse is a good substitute for wood as a boiler fuel, as it has a similar calorific value but fewer emissions. (Author)

Emission of Tc-99 from nuclear facilities

International Nuclear Information System (INIS)

Luxenburger, H.J.; Schuettelkopf, H.; Bohn, B.

1984-11-01

No noticeable Tc-activities are emitted from nuclear power stations. The emissions with the gaseous effluents exceed but rarely the detection limit of 25 nCi/h. Likewise, the emission with the liquid effluents remains below the detection limit of about 0.5 nCi/m 3 . Neither can a remarkable emission be recorded from the facilities of the Central Decontamination Services Department (HDB) of KfK. The emissions from the evaporation system for low level solutions and from the evaporation system for low level solutions and from the incineration facility for solid wastes do not exceed or rarely exceed to a minor extent the detection limit of 0.3 pCi/m 3 waste air. Also with the liquid effluents only minor Tc-amounts are discharged of 0.3 nCi/m 3 at the maximum. In the distillate of the medium level solutions discharged from the Karlsruhe Reprocessing Plant (WAK) to HDB as so-called tritiated water 2 nCi/m 3 Tc-99 at the maximum are contained. Only in the gaseous effluents from the evaporation system for medium level solutions emissions of up to 14 pCi/m 3 can be detected. The detection limits are almost permanently exceeded by the gaseous effluents from WAK. Small amounts of Tc-99 of 7 pCi/m 3 exhaust air at the maximum are released to the environment. However, the amount of Tc accumulated over the sampling period is insignificant from the radioecological point of view. (orig./HP) [de

Polycyclic Aromatic Hydrocarbon Emission in Spitzer /IRS Maps. II. A Direct Link between Band Profiles and the Radiation Field Strength

Energy Technology Data Exchange (ETDEWEB)

Stock, D. J.; Peeters, E., E-mail: dstock84@gmail.com [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada)

2017-03-10

We decompose the observed 7.7 μ m polycyclic aromatic hydrocarbon (PAH) emission complexes in a large sample of over 7000 mid-infrared spectra of the interstellar medium using spectral cubes observed with the Spitzer /IRS-SL instrument. In order to fit the 7.7 μ m PAH emission complex we invoke four Gaussian components, which are found to be very stable in terms of their peak positions and widths across all of our spectra, and subsequently define a decomposition with fixed parameters, which gives an acceptable fit for all the spectra. We see a strong environmental dependence on the interrelationships between our band fluxes—in the H ii regions all four components are intercorrelated, while in the reflection nebulae (RNs) the inner and outer pairs of bands correlate in the same manner as previously seen for NGC 2023. We show that this effect arises because the maps of RNs are dominated by emission from strongly irradiated photodissociation regions, while the much larger maps of H ii regions are dominated by emission from regions much more distant from the exciting stars, leading to subtly different spectral behavior. Further investigation of this dichotomy reveals that the ratio of two of these components (centered at 7.6 and 7.8 μ m) is linearly related to the UV-field intensity (log G {sub 0}). We find that this relationship does not hold for sources consisting of circumstellar material, which are known to have variable 7.7 μ m spectral profiles.

Aromatic hydrocarbons

International Nuclear Information System (INIS)

Roder, M.

1985-01-01

Papers dealing with radiolysis of aromatic hydrocarbons of different composition (from benzene to terphenyls and hydrocarbons with condensed rings) as well as their mixtures (with alkanes, alkenes, other aromatic hydrocarbons) are reviewed. High radiation stability of aromatic hydrocarbons in condensed phases associated with peculiarities of molecular structure of compounds is underlined. Mechanisms of radiolytic processes, vaues of product yields are considered

Light particle emission measurements in heavy ion reactions. Final report, June 1, 1981-May 31, 1984

International Nuclear Information System (INIS)

Petitt, G.A.

1984-01-01

Progress in instrumentation development reported includes improvements in the design of position sensitive neutron detectors, design of a thin-walled, spherical, aluminum target chamber, and use of thin silicon detectors to detect and identify evaporation residues from fusion reactions. The problem of the short lifetime of evaporation residue detectors is addressed by using a pair of large area, multi-wire proportional counters followed by a thin sheet of plastic scintillator. Neutron emission associated with fission has been studied, as well as nonequilibrium emission associated with inelastic products and evaporation residue. An experiment was performed to study neutron emission associated with fission and fission-like events in the case of the Er composite system. Other work in progress includes neutron emissions from the C + Gd and Ne + Nd reactions. 9 refs

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

Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure

Science.gov (United States)

Canpolat, Nurtac

2006-01-01

This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

Determination of Summertime VOC Emission Rates from Produced Water Ponds in the Uintah Basin

Science.gov (United States)

Martin, R. S.; Woods, C.; Lyman, S.

2013-12-01

The observance of excess ozone concentrations in Utah's Uintah Basin over past several years has prompted several investigations into the extent and causes of the elevated ozone. Among these is the assessment of potential emissions of reactive VOCs. Evaporation ponds, used a remediation technique for treatment of contaminated production and other waters, are one potential source of significant VOC emissions and is estimated that there are around 160 such ponds within the Uintah Basin's oil and gas production areas. In June 2012 VOC emission rates for several reactive VOCs were derived for an evaporation facility consisting of a small inlet pond (≈0.03 acres) and two larger, serial ponds (≈4.3 acres each). The emission rates were determined over three sampling periods using an inverse modeling approach. Under this methodology, ambient VOC concentrations are determined at several downwind locations through whole-air collection into SUMMA canisters, followed by GC/MS quantification and compared with predicted concentrations using an EPA-approved dispersion model, AERMOD. The presumed emission rates used within the model were then adjusted until the modeled concentrations approach the observed concentrations. The derived emission rates for the individual VOCs were on the order of 10-3 g/s/m2 from the inlet pond and 10-6 g/s/m2 from the larger ponds. The emissions from the 1st pond in series after the inlet pond were about 3-4x the emissions from the 2nd pond. These combined emission rates are about an order of magnitude those reported for a single study in Colorado (Thoma, 2009). It should be noted, however, that the variability about each of the VOC emission rates was significant (often ×100% at the 95% confidence interval). Extrapolating these emission rates to the estimated total areas of all the evaporation ponds within Basin resulted in calculated Basin-wide VOC emissions 292,835 tons/yr. However, Bar-Ilan et al. (2009) estimated 2012 VOC oil and gas related

Impact of cold temperature on Euro 6 passenger car emissions.

Science.gov (United States)

Suarez-Bertoa, Ricardo; Astorga, Covadonga

2018-03-01

Hydrocarbons, CO, NOx, NH 3 , N 2 O, CO 2 and particulate matter emissions affect air quality, global warming and human health. Transport sector is an important source of these pollutants and high pollution episodes are often experienced during the cold season. However, EU vehicle emissions regulation at cold ambient temperature only addresses hydrocarbons and CO vehicular emissions. For that reason, we have studied the impact that cold ambient temperatures have on Euro 6 diesel and spark ignition (including: gasoline, ethanol flex-fuel and hybrid vehicles) vehicle emissions using the World-harmonized Light-duty Test Cycle (WLTC) at -7 °C and 23 °C. Results indicate that when facing the WLTC at 23 °C the tested vehicles present emissions below the values set for type approval of Euro 6 vehicles (still using NEDC), with the exception of NOx emissions from diesel vehicles that were 2.3-6 times higher than Euro 6 standards. However, emissions disproportionally increased when vehicles were tested at cold ambient temperature (-7 °C). High solid particle number (SPN) emissions (>1 × 10 11 # km -1 ) were measured from gasoline direct injection (GDI) vehicles and gasoline port fuel injection vehicles. However, only diesel and GDI SPN emissions are currently regulated. Results show the need for a new, technology independent, procedure that enables the authorities to assess pollutant emissions from vehicles at cold ambient temperatures. Harmful pollutant emissions from spark ignition and diesel vehicles are strongly and negatively affected by cold ambient temperatures. Only hydrocarbon, CO emissions are currently regulated at cold temperature. Therefore, it is of great importance to revise current EU winter vehicle emissions regulation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Hydrothermal waves in evaporating sessile drops

OpenAIRE

Brutin, D.; Rigollet, F.; Niliot, C. Le

2009-01-01

Drop evaporation is a simple phenomena but still unclear concerning the mechanisms of evaporation. A common agreement of the scientific community based on experimental and numerical work evidences that most of the evaporation occurs at the triple line. However, the rate of evaporation is still empirically predicted due to the lack of knowledge on the convection cells which develop inside the drop under evaporation. The evaporation of sessile drop is more complicated than it appears due to the...

40 CFR 1054.103 - What exhaust emission standards must my handheld engines meet?

Science.gov (United States)

2010-07-01

... emission family are designed to operate. You must meet the numerical emission standards for hydrocarbons in... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, SMALL NONROAD SPARK...

40 CFR 1054.105 - What exhaust emission standards must my nonhandheld engines meet?

Science.gov (United States)

2010-07-01

... emission family are designed to operate. You must meet the numerical emission standards for hydrocarbons in... PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, SMALL NONROAD SPARK...

Characteristics of polycyclic aromatic hydrocarbon (PAH) emissions from a UH-1H helicopter engine and its impact on the ambient environment

Science.gov (United States)

Chen, Yu-Cheng; Lee, Wen-Jhy; Uang, Shi-Nian; Lee, Su-Hsing; Tsai, Perng-Jy

The objective of this study is to characterize the emissions of polycyclic aromatic hydrocarbons (PAHs) from a UH-1H helicopter turboshaft engine and its impact on the ambient environment. Five power settings of the ground idle (GI), fly idle (FI), beed band check (BBC), inlet guide vane (IGV), and take off (TO) were selected and samples were collected from the exhaust by using an isokinetic sampling system. Twenty-two PAH compounds were analyzed by gas chromatograph (GC)/MS. We found the mean total PAH concentration in the exhaust of the UH-1H engine (843 μg m -3) is 1.05-51.7 times in magnitude higher than those of the heavy-duty diesel (HDD) engine, motor vehicle engine, and F101 aircraft engine. Two- and three-ringed PAHs account for 97.5% of total PAH emissions from the UH-1H engine. The mean total PAH and total BaP eq emission factors for the UH-1H engine (63.4 and 0.309 mg L -1·fuel) is 1.65-23.4 and 1.30-7.54 times in magnitude higher than those for the motor vehicle engine, HDD engine, and F101 aircraft engine. The total emission level of the single PAH compound, BaP, for the UH-1H engine (EL BaP) during one landing and take off (LTO) cycle (2.19 mg LTO -1) was higher than the European Commission standard (1.24 mg LTO -1) suggesting that appropriate measures should be taken to reduce PAH emissions from UH-1H engines in the future.

Recent trends of the emission characteristics from the road construction industry.

Science.gov (United States)

Chauhan, Sippy K; Sharma, Sangita; Shukla, Anuradha; Gangopadhyay, S

2010-11-01

Bitumen is a black, thermoplastic, hydrocarbon material derived from the processing of crude oil. At ambient temperature, bitumen is solid and does not present any health/environmental risks. This is one of the main reasons that bitumen is widely used for road construction all over the world. But during manufacturing/modification according to its application, storage, transportation, and use of bitumen is heated giving off various hydrocarbons emissions. In recent years, there has been increasing interest in investigating the potential of bitumen emissions to cause health effects. This is mainly because of the reason that bitumen has small amount of poly-aromatic hydrocarbons, along with some other volatiles like benzene, toluene, etc., which are known to be carcinogenic in nature. Thus, assessment of the emission characteristics and health hazards of bitumen fumes may have far reaching industrial economic and public health implications. In this review, we will discuss about the emission characteristics from bitumen, asphalts, or road construction, which is mainly contributed by bitumen fumes. Sampling strategies and analytical methods employed are also described briefly.

Does evaporation paradox exist in China?

Directory of Open Access Journals (Sweden)

Z. T. Cong

2009-03-01

Full Text Available One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called "evaporation paradox". Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The conclusions include: (1 From 1956 to 2005, pan evaporation paradox existed in China as a whole while pan evaporation kept decreasing and air temperature became warmer and warmer, but it does not apply to Northeast and Southeast China; (2 From 1956 to 1985, pan evaporation paradox existed narrowly as a whole with unobvious climate warming trend, but it does not apply to Northeast China; (3 From 1986 to 2005, in the past 20 years, pan evaporation paradox did not exist for the whole period while pan evaporation kept increasing, although it existed in South China. Furthermore, the trend of other weather factors including sunshine duration, windspeed, humidity and vapor pressure deficit, and their relations with pan evaporation are discussed. As a result, it can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the decreasing in vapor pressure deficit due to strong warming after 1986. With the Budyko curve, it can be concluded that the actual evaporation decreased in the former 30 years and increased in the latter 20 year for the whole China.

Spin distribution of evaporation residues formed in complete and incomplete fusion in 16O+154Sm system

Science.gov (United States)

Singh, D.; Linda, Sneha B.; Giri, Pankaj K.; Mahato, Amritraj; Tripathi, R.; Kumar, Harish; Afzal Ansari, M.; Sathik, N. P. M.; Ali, Rahbar; Kumar, Rakesh; Muralithar, S.; Singh, R. P.

2017-11-01

Spin distributions for several evaporation residues populated in the 16O+154Sm system have been measured at projectile energy ≈ 6.2 MeV/A by using the charged particle-γ-coincidence technique. The measured spin distributions of the evaporation residues populated through incomplete fusion associated with 'fast' α and 2α-emission channels are found to be entirely different from fusion-evaporation channels. It is observed that the mean input angular momentum for the evaporation residues formed in incomplete fusion channel is relatively higher than that observed for evaporation residues in complete fusion channels. The feeding intensity profile of evaporation residues populated through complete fusion and incomplete fusion have also been studied. The incomplete fusion channels are found to have narrow range feeding only for high spin states, while complete fusion channels are strongly fed over a broad spin range and widely populated. Comparison of present results with earlier data suggests that the mean input angular momentum values are relatively smaller for spherical target than that of deformed target using the same projectile and incident energy highlighting the role of target deformation in incomplete fusion dynamics.

Spin distribution of evaporation residues formed in complete and incomplete fusion in 16O+154Sm system

Directory of Open Access Journals (Sweden)

D. Singh

2017-11-01

Full Text Available Spin distributions for several evaporation residues populated in the 16O+154Sm system have been measured at projectile energy ≈ 6.2 MeV/A by using the charged particle–γ-coincidence technique. The measured spin distributions of the evaporation residues populated through incomplete fusion associated with ‘fast’ α and 2α-emission channels are found to be entirely different from fusion–evaporation channels. It is observed that the mean input angular momentum for the evaporation residues formed in incomplete fusion channel is relatively higher than that observed for evaporation residues in complete fusion channels. The feeding intensity profile of evaporation residues populated through complete fusion and incomplete fusion have also been studied. The incomplete fusion channels are found to have narrow range feeding only for high spin states, while complete fusion channels are strongly fed over a broad spin range and widely populated. Comparison of present results with earlier data suggests that the mean input angular momentum values are relatively smaller for spherical target than that of deformed target using the same projectile and incident energy highlighting the role of target deformation in incomplete fusion dynamics.

Evaporation studies of liquid oxide fuel at very high temperatures using laser beam heating

International Nuclear Information System (INIS)

Bober, M.; Breitung, W.; Karow, H.U.; Schretzmann, K.

1976-11-01

Evaporation experiments with oxide fuel are carried out based laser beam heating of the fuel specimen surface. The measuring quantities are the recoil momentum of the target, the evaporation area, the evaporation time and the mass and momentum of the supersonic vapor jet expanding into vacuum, and the thermal radiation density of the evaporating surface. From the mechanical measuring quantities we derive the vapor pressure of the target material and, in a first approach, also the evaporation temperature by applying a gas dynamic evaluation model. In a second approach, after having measured the spectral emissivity of liquid UO 2 at 633 nm, we determine the evaporation temperature at the liquid surface also from its thermal radiation. For the determination of the vapor pressure from the measured quantities a gas dynamic evaluation model has been developed. An application limit of the measuring technique is given by onset of plasma interaction of the vapor plume with the incident laser beam at temperatures above 4500 K. Experimental values for the saturated vapor pressure of UO 2 are presented, determined from three series of laser evaporation measurements obtained at temperatures around 3500 K, 3950 K, and 4200 K. The average vapor pressures found are 0.6 bar, 3 bar, and 7 bar, respectively. Laser vapor pressure measurements performed by other authors and theoretical extrapolations of the UO 2 vapor pressure curve known from literature show fairly good agreement within their confidence interval with the vapor pressure measurements reported here. (orig./HR) [de

PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

International Nuclear Information System (INIS)

Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J.

2011-01-01

We reconsider the contribution that singly protonated polycyclic aromatic hydrocarbons (PAHs; HPAH + s) might make to the Class A component of the 6.2 μm interstellar emission feature in light of the recent experimental measurements of protonated naphthalene and coronene. Our calculations on the small HPAH + s have a band near 6.2 μm, as found in experiment. While the larger HPAH + s still have emission near 6.2 μm, the much larger intensity of the band near 6.3 μm overwhelms the weaker band at 6.2 μm, so that the 6.2 μm band is barely visible. Since the large PAHs are more representative of those in the interstellar medium, our work suggests that large HPAH + s cannot be major contributors to the observed emission at 6.2 μm (i.e., Class A species). Saturating large PAH cations with hydrogen atoms retains the 6.2 μm Class A band position, but the rest of the spectrum is inconsistent with observed spectra.

Microwave heating type evaporator

International Nuclear Information System (INIS)

Taura, Masazumi; Nishi, Akio; Morimoto, Takashi; Izumi, Jun; Tamura, Kazuo; Morooka, Akihiko.

1987-01-01

Purpose: To prevent evaporization stills against corrosion due to radioactive liquid wastes. Constitution: Microwaves are supplied from a microwave generator by way of a wave guide tube and through a microwave permeation window to the inside of an evaporatization still. A matching device is attached to the wave guide tube for transmitting the microwaves in order to match the impedance. When the microwaves are supplied to the inside of the evaporization still, radioactive liquid wastes supplied from a liquid feed port by way of a spray tower to the inside of the evaporization still is heated and evaporated by the induction heating of the microwaves. (Seki, T.)

Multi-year (2004–2008 record of nonmethane hydrocarbons and halocarbons in New England: seasonal variations and regional sources

Directory of Open Access Journals (Sweden)

R. S. Russo

2010-05-01

Full Text Available Multi-year time series records of C₂-C₆ alkanes, C₂-C₄ alkenes, ethyne, isoprene, C₆-C₈ aromatics, trichloroethene (C₂HCl₃, and tetrachloroethene (C₂Cl₄ from canister samples collected during January 2004–February 2008 at the University of New Hampshire (UNH AIRMAP Observatory at Thompson Farm (TF in Durham, NH are presented. The objectives of this work are to identify the sources of nonmethane hydrocarbons (NMHCs and halocarbons observed at TF, characterize the seasonal and interannual variability in ambient mixing ratios and sources, and estimate regional emission rates of NMHCs. Analysis of correlations and comparisons with emission ratios indicated that a ubiquitous and persistent mix of emissions from several anthropogenic sources is observed throughout the entire year. The highest C₂-C₈ anthropogenic NMHC mixing ratios were observed in mid to late winter. Following the springtime minimums, the C₃-C₆ alkanes, C₇-C₈ aromatics, and C₂HCl₃ increased in early to mid summer, presumably reflecting enhanced evaporative emissions. Mixing ratios of C₂Cl₄ and C₂HCl₃ decreased by 0.7±0.2 and 0.3±0.05 pptv/year, respectively, which is indicative of reduced usage and emissions of these halogenated solvents. Emission rates of C₃-C₈ NMHCs were estimated to be 10⁹ to 10¹⁰ molecules cm⁻² s⁻¹ in winter 2006. The emission rates extrapolated to the state of New Hampshire and New England were ~2–60 Mg/day and ~12–430 Mg/day, respectively. Emission rates of benzene, toluene, ethylbenzene, xylenes, and ethyne in the 2002 and 2005 EPA National Emissions Inventories were within ±50% of the TF emission rates.

PROBING THE IONIZATION STATES OF POLYCYCLIC AROMATIC HYDROCARBONS VIA THE 15–20 μm EMISSION BANDS

Energy Technology Data Exchange (ETDEWEB)

Shannon, M. J.; Stock, D. J.; Peeters, E., E-mail: mshann3@uwo.ca [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada)

2015-10-01

We report new correlations between ratios of band intensities of the 15–20 μm emission bands of polycyclic aromatic hydrocarbons (PAHs) in a sample of 57 sources observed with the Spitzer/Infrared Spectrograph. This sample includes Large Magellanic Cloud point sources from the SAGE-Spec survey, nearby galaxies from the Spitzer Infrared Nearby Galaxies Survey survey, two Galactic interstellar medium cirrus sources, and the spectral maps of the Galactic reflection nebulae NGC 2023 and NGC 7023. We find that the 16.4, 17.4, and 17.8 μm band intensities are inter-correlated in all environments. In NGC 2023 and NGC 7023 these bands also correlate with the 11.0 and 12.7 μm band intensities. The 15.8 μm band correlates only with the 15–18 μm plateau and the 11.2 μm emission. We examine the spatial morphology of these bands and introduce radial cuts. We find that these bands can be spatially organized into three sets: the 12.7, 16.4, and 17.8 μm bands; the 11.2, 15.8 μm bands and the 15–18 μm plateau; and the 11.0 and 17.4 μm bands. We also find that the spatial distribution of the 12.7, 16.4, and 17.8 μm bands can be reconstructed by averaging the spatial distributions of the cationic 11.0 μm and neutral 11.2 μm bands. We conclude that the 17.4 μm band is dominated by cations, the 15.8 μm band by neutral species, and the 12.7, 16.4, and 17.8 μm bands by a combination of the two. These results highlight the importance of PAH ionization for spatially differentiating sub-populations by their 15–20 μm emission variability.

Net Ecosystem Fluxes of Hydrocarbons from a Ponderosa Pine Forest in Colorado

Science.gov (United States)

Rhew, R. C.; Turnipseed, A. A.; Ortega, J. V.; Smith, J. N.; Guenther, A. B.; Shen, S.; Martinez, L.; Koss, A.; Warneke, C.; De Gouw, J. A.; Deventer, M. J.

2015-12-01

Light (C2-C4) alkenes, light alkanes and isoprene (C5H8) are non-methane hydrocarbons that play important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. Natural terrestrial fluxes of the light hydrocarbons are poorly characterized, with global emission estimates based on limited field measurements. In 2014, net fluxes of these compounds were measured at the Manitou Experimental Forest Observatory, a semi-arid ponderosa pine forest in the Colorado Rocky Mountains and site of the prior BEACHON campaigns. Three field intensives were conducted between June 17 and August 10, 2014. Net ecosystem flux measurements utilized a relaxed eddy accumulation system coupled to an automated gas chromatograph. Summertime average emissions of ethene and propene were up to 90% larger than those observed from a temperate deciduous forest. Ethene and propene fluxes were also correlated to each other, similar to the deciduous forest study. Emissions of isoprene were small, as expected for a coniferous forest, and these fluxes were not correlated with either ethene or propene. Unexpected emissions of light alkanes were also observed, and these showed a distinct diurnal cycle. Understory flux measurements allowed for the partitioning of fluxes between the surface and the canopy. Full results from the three field intensives will be compared with environmental variables in order to parameterize the fluxes for use in modeling emissions.

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.

Vapor-based interferometric measurement of local evaporation rate and interfacial temperature of evaporating droplets.

Science.gov (United States)

Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

2014-03-04

The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory.

Estimating the Biogenic Non-Methane Hydrocarbon Emissions over Greece

Directory of Open Access Journals (Sweden)

Ermioni Dimitropoulou

2018-01-01

Full Text Available Biogenic emissions affect the urban air quality as they are ozone and secondary organic aerosol (SOA precursors and should be taken into account when applying photochemical pollution models. The present study presents an estimation of the magnitude of non-methane volatile organic compounds (BNMVOCs emitted by vegetation over Greece. The methodology is based on computation developed with the aid of a Geographic Information System (GIS and theoretical equations in order to produce an emission inventory on a 6 × 6 km2 spatial resolution, in a temporal resolution of 1 h covering one year (2016. For this purpose, a variety of input data was used: updated satellite land-use data, land-use specific emission potentials, foliar biomass densities, temperature, and solar radiation data. Hourly, daily, and annual isoprene, monoterpenes, and other volatile organic compounds (OVOCs were estimated. In the area under study, the annual biogenic emissions were estimated up to 472 kt, consisting of 46.6% isoprene, 28% monoterpenes, and 25.4% OVOCs. Results delineate an annual cycle with increasing values from March to April, while maximum emissions were observed from May to September, followed by a decrease from October to January.

Hydrocarbon characterization experiments in fully turbulent fires : results and data analysis.

Energy Technology Data Exchange (ETDEWEB)

Suo-Anttila, Jill Marie; Blanchat, Thomas K.

2011-03-01

As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. The model for the fuel evaporation rate in a liquid fuel pool fire is significant because in well-ventilated fires the evaporation rate largely controls the total heat release rate from the fire. This report describes a set of fuel regression rates experiments to provide data for the development and validation of models. The experiments were performed with fires in the fully turbulent scale range (> 1 m diameter) and with a number of hydrocarbon fuels ranging from lightly sooting to heavily sooting. The importance of spectral absorption in the liquid fuels and the vapor dome above the pool was investigated and the total heat flux to the pool surface was measured. The importance of convection within the liquid fuel was assessed by restricting large scale liquid motion in some tests. These data sets provide a sound, experimentally proven basis for assessing how much of the liquid fuel needs to be modeled to enable a predictive simulation of a fuel fire given the couplings between evaporation of fuel from the pool and the heat release from the fire which drives the evaporation.

Thermogravimetric analysis of fuel film evaporation

Institute of Scientific and Technical Information of China (English)

HU Zongjie; LI Liguang; YU Shui

2006-01-01

Thermogravimetric analysis (TGA) was compared with the petrochemical distillation measurement method to better understand the characteristics of fuel film evaporation at different wall tem- peratures. The film evaporation characteristics of 90# gasoline, 93# gasoline and 0# diesel with different initial thicknesses were investigated at different environmental fluxes and heating rates. The influences of heating rate, film thickness and environmental flux on fuel film evaporation for these fuels were found. The results showed that the environmental conditions in TGA were similar to those for fuel films in the internal combustion engines, so data from TGA were suitable for the analysis of fuel film evaporation. TGA could simulate the key influencing factors for fuel film evaporation and could investigate the basic quantificational effect of heating rate and film thickness. To get a rapid and sufficient fuel film evaporation, sufficiently high wall temperature is necessary. Evaporation time decreases at a high heating rate and thin film thickness, and intense gas flow is important to promoting fuel film evaporation. Data from TGA at a heating rate of 100℃/min are fit to analyze the diesel film evaporation during cold-start and warming-up. Due to the tense molecular interactions, the evaporation sequence could not be strictly divided according to the boiling points of each component for multicomponent dissolved mixture during the quick evaporation process, and the heavier components could vaporize before reaching their boiling points. The 0# diesel film would fully evaporate when the wall temperature is beyond 250℃.

Phases of information release during black hole evaporation

International Nuclear Information System (INIS)

Brustein, Ram; Medved, A.J.M.

2014-01-01

In a recent article, we have shown how quantum fluctuations of the background geometry modify Hawking’s density matrix for black hole (BH) radiation. Hawking’s diagonal matrix picks up small off-diagonal elements whose influence becomes larger with the number of emitted particles. We have calculated the “time-of-first-bit', when the first bit of information comes out of the BH, and the “transparency time', when the rate of information release becomes order unity. We have found that the transparency time is equal to the “Page time”, when the BH has lost half of its initial entropy to the radiation, in agreement with Page’s results. Here, we improve our previous calculation by keeping track of the time of emission of the Hawking particles and their back-reaction on the BH. Our analysis reveals a new time scale, the radiation “coherence time”, which is equal to the geometric mean of the evaporation time and the light crossing time. We find, as for our previous treatment, that the time-of-first-bit is equal to the coherence time, which is much shorter than the Page time. But the transparency time is now much later than the Page time, just one coherence time before the end of evaporation. Close to the end, when the BH is parametrically of Planckian dimensions but still large, the coherence time becomes parametrically equal to the evaporation time, thus allowing the radiation to purify. We also determine the time dependence of the entanglement entropy of the early and late-emitted radiation. This entropy is small during most of the lifetime of the BH, but our qualitative analysis suggests that it becomes parametrically maximal near the end of evaporation

Properties, performance and emissions of biofuels in blends with gasoline

Science.gov (United States)

Eslami, Farshad

The emission performance of fuels and their blends in modern combustion systems have been studied with the purpose of reducing regulated and unregulated emissions, understanding of exhaust products of fuels such as gasoline, ethanol and 2,5-dimethylfuran and comparison of results. A quantitative analysis of individual hydrocarbon species from exhaust emissions of these three fuels were carried out with direct injects spark ignition (DISI) single cylinder engine. The analysis of hydrocarbon species were obtained using gas chromatography-mass spectrometry (GCMS) connected on-line to SI engine. During this project, novel works have been done including the set up of on-line exhaust emission measurement device for detection and quantification of individual volatile hydrocarbons. Setting of a reliable gas chromatography mass spectrometry measurement system required definition and development of a precise method. Lubricity characteristics of biofuels and gasoline were investigated using High Frequency Reciprocating Rig (HFRR). Results showed great enhancing lubricity characteristics of biofuels when added to conventional gasoline. 2,5-dimenthylfuran was found to be the best among the fuels used, addition of this fuel to gasoline also showed better result compared with ethanol addition.

Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D.; Hoffman, T. [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1995-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)

Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D; Hoffman, T [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1996-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)

Water addition, evaporation and water holding capacity of poultry litter.

Science.gov (United States)

Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

2015-12-15

Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25°C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

The Hawking evaporation process of rapidly-rotating black holes: an almost continuous cascade of gravitons

International Nuclear Information System (INIS)

Hod, Shahar

2015-01-01

It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ gap /τ emission = O(1), where τ gap is the average time gap between the emissions of successive Hawking quanta and τ emission is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)

The Hawking evaporation process of rapidly-rotating black holes: an almost continuous cascade of gravitons

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emek Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)

2015-07-15

It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ{sub gap}/τ{sub emission} = O(1), where τ{sub gap} is the average time gap between the emissions of successive Hawking quanta and τ{sub emission} is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)

The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (H(sub n)-PAHs) and their Relation to the 3.4 and 6.9 Micrometer PAH Emission Features

Science.gov (United States)

Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

2013-01-01

A population of polycyclic aromatic hydrocarbons (PAHs) and related materials are thought to be responsible for the family of infrared emission features that are seen towards a wide variety of astrophysical environments. A potentially important subclass of these materials are polycyclic aromatic hydrocarbons whose edges contain excess H atoms (H(sub n)-PAHs). While it has been suggested that this type of compound may be present in the interstellar population, it has been difficult to properly assess this possibility because of a lack of suitable infrared laboratory spectra to assist with analysis of the astronomical data. We present the 4000-500 cm(exp -1) (2.5-20 micrometers) infrared spectra of 23 H(sub n)-PAHs and related molecules isolated in argon matrices, under conditions suitable for use in the interpretation of astronomical data. The spectra of molecules with mixed aromatic and aliphatic domains show unique characteristics that distinguish them from their fully aromatic PAH equivalents. We discuss the changes to the spectra of these types of molecules as they transition from fully aromatic to fully aliphatic forms. The implications for the interpretation of astronomical spectra are discussed with specific emphasis on the 3.4 and 6.9 micrometer features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, in addition to IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 micrometer features. We show that 'normal' PAH emission objects contain relatively few H(sub n)-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

Advanced evaporation/concentration treatment technology for radioactive liquid waste

International Nuclear Information System (INIS)

Zhang Zhijian; Lu Zhiming; Yu Ruixia

1997-01-01

A new and effective two stage moisture separator which removes remaining water droplet and free ion in secondary steam can be added between the evaporator and the condenser of existing liquid waste treatment system. Its addition increases decontamination factor to more than ten times. Ion content in condensed water is decreased considerably. Condensed water meets emission standard without passing through ion exchanger. Detail fundamentals are analysed and results are given: (1) system diagram, (2) structure sketch of the two stage moisture separator, (3) laboratory test results

WTP Pilot-Scale Evaporation Tests

International Nuclear Information System (INIS)

QURESHI, ZAFAR

2004-01-01

This report documents the design, assembly, and operation of a Pilot-Scale Evaporator built and operated by SRTC in support of Waste Treatment Plant (WTP) Project at the DOE's Hanford Site. The WTP employs three identical evaporators, two for the Waste Feed and one for the Treated LAW. The Pilot-Scale Evaporator was designed to test simulants for both of these waste streams. The Pilot-Scale Evaporator is 1/76th scale in terms of evaporation rates. The basic configuration of forced circulation vacuum evaporator was employed. A detailed scaling analysis was performed to preserve key operating parameters such as basic loop configuration, system vacuum, boiling temperature, recirculation rates, vertical distances between important hardware pieces, reboiler heat transfer characteristics, vapor flux, configuration of demisters and water spray rings. Three evaporation test campaigns were completed. The first evaporation run used water in order to shake down the system. The water runs were important in identifying a design flaw that inhibited mixing in the evaporator vessel, thus resulting in unstable boiling operation. As a result the loop configuration was modified and the remaining runs were completed successfully. Two simulant runs followed the water runs. Test 1: Simulated Ultrafiltration Recycles with HLW SBS, and Test 2: Treated AN102 with Envelop C LAW. Several liquid and offgas samples were drawn from the evaporator facility for regulatory and non-regulatory analyses. During Test 2, the feed and the concentrate were spiked with organics to determine organic partitioning. The decontamination factor (DF) for Test 1 was measured to be 110,000 (more than the expected value of 100,000). Dow Corning Q2-3183A antifoam agent was tested during both Tests 1 and 2. It was determined that 500 ppm of this antifoam agent was sufficient to control the foaminess to less than 5 per cent of the liquid height. The long-term testing (around 100 hours of operation) did not show any

Variation of ambient non-methane hydrocarbons in Beijing city in summer 2008

Directory of Open Access Journals (Sweden)

B. Wang

2010-07-01

Full Text Available In conjunction with hosting the 2008 Beijing Olympics, the municipal government implemented a series of stringent air quality control measures. To assess the impacts on variation of ambient non-methane hydrocarbons (NMHCs, the whole air was sampled by canisters at one urban site and two suburban sites in Beijing, and 55 NMHC species were quantified by gas chromatography equipped with a quadrupole mass spectrometer and a flame ionization detector (GC/MSD/FID as parts of the field Campaign for the Beijing Olympic Games Air Quality program (CareBeijing. According to the control measures, the data were presented according to four periods: 18–30 June, 8–19 July, 15–24 August (during the Olympic Games, and 6–15 September (during the Paralympic Games. Compared with the levels in June, the mixing ratios of NMHCs obtained in the Olympic and Paralympic Games periods were reduced by 35% and 25%, respectively. Source contributions were calculated using a chemical mass balance model (CMB 8.2. After implementing the control measures, emissions from target sources were obviously reduced, and reductions in vehicle exhaust could explain 48–82% of the reductions of ambient NMHCs. Reductions in emissions from gasoline evaporation, paint and solvent use, and the chemical industry contributed 9–40%, 3–24%, and 1–5%, respectively, to reductions of ambient NMHCs. Sources of liquefied petroleum gas (LPG and biogenic emissions were not controlled, and contributions from these sources from July to September were stable or even higher than in June. Ozone formation potentials (OFPs were calculated for the measured NMHCs. The total OFPs during the Olympic and Paralympic Games were reduced by 48% and 32%, respectively, compared with values in June. Reductions in the OFPs of alkenes and aromatics explained 77–92% of total OFP reductions. The alkenes and aromatics were mainly from vehicle exhausts, and reductions of vehicle exhaust gases explained 67–87% of

Variation of ambient non-methane hydrocarbons in Beijing city in summer 2008

Science.gov (United States)

Wang, B.; Shao, M.; Lu, S. H.; Yuan, B.; Zhao, Y.; Wang, M.; Zhang, S. Q.; Wu, D.

2010-07-01

In conjunction with hosting the 2008 Beijing Olympics, the municipal government implemented a series of stringent air quality control measures. To assess the impacts on variation of ambient non-methane hydrocarbons (NMHCs), the whole air was sampled by canisters at one urban site and two suburban sites in Beijing, and 55 NMHC species were quantified by gas chromatography equipped with a quadrupole mass spectrometer and a flame ionization detector (GC/MSD/FID) as parts of the field Campaign for the Beijing Olympic Games Air Quality program (CareBeijing). According to the control measures, the data were presented according to four periods: 18-30 June, 8-19 July, 15-24 August (during the Olympic Games), and 6-15 September (during the Paralympic Games). Compared with the levels in June, the mixing ratios of NMHCs obtained in the Olympic and Paralympic Games periods were reduced by 35% and 25%, respectively. Source contributions were calculated using a chemical mass balance model (CMB 8.2). After implementing the control measures, emissions from target sources were obviously reduced, and reductions in vehicle exhaust could explain 48-82% of the reductions of ambient NMHCs. Reductions in emissions from gasoline evaporation, paint and solvent use, and the chemical industry contributed 9-40%, 3-24%, and 1-5%, respectively, to reductions of ambient NMHCs. Sources of liquefied petroleum gas (LPG) and biogenic emissions were not controlled, and contributions from these sources from July to September were stable or even higher than in June. Ozone formation potentials (OFPs) were calculated for the measured NMHCs. The total OFPs during the Olympic and Paralympic Games were reduced by 48% and 32%, respectively, compared with values in June. Reductions in the OFPs of alkenes and aromatics explained 77-92% of total OFP reductions. The alkenes and aromatics were mainly from vehicle exhausts, and reductions of vehicle exhaust gases explained 67-87% of reductions in alkenes and 38

Evaporation of Lennard-Jones clusters

International Nuclear Information System (INIS)

Roman, C.E.; Garzon, I.L.

1991-01-01

Extensive molecular dynamics simulations have been done to study the evaporation of a 13-atom Lennard-Jones cluster. The survival probability and the evaporative lifetime are calculated as a function of the cluster total energy from a classical trajectory analysis. The results are interpreted in terms of the RRK theory of unimolecular dissociation. The calculation of the binding energy of the evaporated species from the evaporation rate and the average kinetic energy release is discussed. (orig.)

Control of harmful hydrocarbon species in the exhaust of modern advanced GDI engines

Science.gov (United States)

Hasan, A. O.; Abu-jrai, A.; Turner, D.; Tsolakis, A.; Xu, H. M.; Golunski, S. E.; Herreros, J. M.

2016-03-01

A qualitative and quantitative analysis of toxic but currently non-regulated hydrocarbon compounds ranging from C5-C11, before and after a zoned three-way catalytic converter (TWC) in a modern gasoline direct injection (GDI) engine has been studied using gas chromatography-mass spectrometry (GC-MS). The GDI engine has been operated under conventional and advanced combustion modes, which result in better fuel economy and reduced levels of NOx with respect to standard SI operation. However, these fuel-efficient conditions are more challenging for the operation of a conventional TWC, and could lead to higher level of emissions released to the environment. Lean combustion leads to the reduction in pumping losses, fuel consumption and in-cylinder emission formation rates. However, lean HCCI will lead to high levels of unburnt HCs while the presence of oxygen will lower the TWC efficiency for NOx control. The effect on the catalytic conversion of the hydrocarbon species of the addition of hydrogen upstream the catalyst has been also investigated. The highest hydrocarbon engine-out emissions were produced for HCCI engine operation at low engine load operation. The catalyst was able to remove most of the hydrocarbon species to low levels (below the permissible exposure limits) for standard and most of the advanced combustion modes, except for naphthalene (classified as possibly carcinogenic to humans by the International Agency for Research on Cancer) and methyl-naphthalene (which has the potential to cause lung damage). However, when hydrogen was added upstream of the catalyst, the catalyst conversion efficiency in reducing methyl-naphthalene and naphthalene was increased by approximately 21%. This results in simultaneous fuel economy and environmental benefits from the effective combination of advanced combustion and novel aftertreatment systems.

Evaporation of inclined water droplets

Science.gov (United States)

Kim, Jin Young; Hwang, In Gyu; Weon, Byung Mook

2017-01-01

When a drop is placed on a flat substrate tilted at an inclined angle, it can be deformed by gravity and its initial contact angle divides into front and rear contact angles by inclination. Here we study on evaporation dynamics of a pure water droplet on a flat solid substrate by controlling substrate inclination and measuring mass and volume changes of an evaporating droplet with time. We find that complete evaporation time of an inclined droplet becomes longer as gravitational influence by inclination becomes stronger. The gravity itself does not change the evaporation dynamics directly, whereas the gravity-induced droplet deformation increases the difference between front and rear angles, which quickens the onset of depinning and consequently reduces the contact radius. This result makes the evaporation rate of an inclined droplet to be slow. This finding would be important to improve understanding on evaporation dynamics of inclined droplets. PMID:28205642

Diesel emission control: Catalytic filters for particulate removal

Directory of Open Access Journals (Sweden)

Debora Fino

2007-01-01

Full Text Available The European diesel engine industry represents a vital sector across the Continent, with more than 2 million direct work positions and a turnover of over 400 billion Euro. Diesel engines provide large paybacks to society since they are extensively used to transport goods, services and people. In recent years increasing attention has been paid to the emissions from diesel engines which, like gasoline engine emissions, include carbon monoxide (CO, hydrocarbons (HC and oxides of nitrogen (NOx. Diesel engines also produce significant levels of particulate matter (PM, which consists mostly of carbonaceous soot and a soluble organic fraction (SOF of hydrocarbons that have condensed on the soot.

Cooking with Fire: The Mutagenicity- and PAH-Emission ...

Science.gov (United States)

Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. We evaluated two categories of solid-fuel cookstoves for 8 pollutant- and 4 mutagenicity-emission factors, correlated the mutagenicity-emission factors, and compared them to those of other combustion emissions. We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS); we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Other than NOx the emission factors per MJd correlated highly among each other (r2 ≥ 0.92); NOx correlated 0.58-0.76 with the other emission factors. Excluding NOx, the NDS and FDS reduced the emission factors on average 68 and 92%, respectively, relative to the TSF. Nonetheless, the mutagenicity-emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was intermediate to that of a large diesel bus engine and a small diesel generator. Both mutagenicity- and pollutant-emission factors may be informative for characterizing cookstove

The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database : The Computed Spectra

NARCIS (Netherlands)

Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; de Armas, F. Sanchez; Saborido, G. Puerta; Hudgins, D. M.; Allamandola, L. J.

The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant

Emissions of polyciclic aromatic hydrocarbons and polyciclic carbonyl biphenils from electric arc furnaces

Directory of Open Access Journals (Sweden)

P. Gomes, J. F.

2008-06-01

Full Text Available This paper describes work done in order to determine the emissions of highly toxic organic micropollutants from electric arc furnaces used in the production of carbon steel from scrap. The study will be allowing to derive relationships between the levels of airborne micropollutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropollutants such as polyciclic aromatic hydrocarbons (PAHs and polycyclic carbonyl biphenils (PCBs emitted by this particular stationary source.

Este artículo contiene resultados del trabajo ejecutado para estudiar la determinación de las emisiones de los micropolutantes orgánicos muy tóxicos que se emiten por los hornos eléctricos de arco utilizados en la producción de acero. Este estudio inicial va a permitir relacionar las concentraciones de polutantes emitidos a la atmósfera con las condiciones de operación del horno eléctrico de arco. Utilizando el método normalizado CEN 1948 para captación y análisis de muestras de compuestos análogos a las dioxinas ha sido posible determinar el perfil característico de los micropolutantes tales como PAHs y PCBs emitidos por esta fuente.

Artificial neural network modeling of jatropha oil fueled diesel engine for emission predictions

Directory of Open Access Journals (Sweden)

Ganapathy Thirunavukkarasu

2009-01-01

Full Text Available This paper deals with artificial neural network modeling of diesel engine fueled with jatropha oil to predict the unburned hydrocarbons, smoke, and NOx emissions. The experimental data from the literature have been used as the data base for the proposed neural network model development. For training the networks, the injection timing, injector opening pressure, plunger diameter, and engine load are used as the input layer. The outputs are hydrocarbons, smoke, and NOx emissions. The feed forward back propagation learning algorithms with two hidden layers are used in the networks. For each output a different network is developed with required topology. The artificial neural network models for hydrocarbons, smoke, and NOx emissions gave R2 values of 0.9976, 0.9976, and 0.9984 and mean percent errors of smaller than 2.7603, 4.9524, and 3.1136, respectively, for training data sets, while the R2 values of 0.9904, 0.9904, and 0.9942, and mean percent errors of smaller than 6.5557, 6.1072, and 4.4682, respectively, for testing data sets. The best linear fit of regression to the artificial neural network models of hydrocarbons, smoke, and NOx emissions gave the correlation coefficient values of 0.98, 0.995, and 0.997, respectively.

Review of Heterogeneous Catalysts for Catalytically Upgrading Vegetable Oils into Hydrocarbon Biofuels

Directory of Open Access Journals (Sweden)

Xianhui Zhao

2017-03-01

Full Text Available To address the issues of greenhouse gas emissions associated with fossil fuels, vegetable oilseeds, especially non-food oilseeds, are used as an alternative fuel resource. Vegetable oil derived from these oilseeds can be upgraded into hydrocarbon biofuel. Catalytic cracking and hydroprocessing are two of the most promising pathways for converting vegetable oil to hydrocarbon biofuel. Heterogeneous catalysts play a critical role in those processes. The present review summarizes current progresses and remaining challenges of vegetable oil upgrading to biofuel. The catalyst properties, applications, deactivation, and regeneration are reviewed. A comparison of catalysts used in vegetable oil and bio-oil upgrading is also carried out. Some suggestions for heterogeneous catalysts applied in vegetable oil upgrading to improve the yield and quality of hydrocarbon biofuel are provided for further research in the future.

POLYCYCLIC AROMATIC HYDROCARBON AND EMISSION LINE RATIOS IN ACTIVE GALACTIC NUCLEI AND STARBURST GALAXIES

International Nuclear Information System (INIS)

Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.

2010-01-01

We study the polycyclic aromatic hydrocarbon (PAH) bands, ionic emission lines, and mid-infrared continuum properties in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. We normalize the spectra at λ = 23 μm and grouped them according to the type of nuclear activity. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T ∼ 150-300 K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7 μm) and the forbidden emission lines of [Si II] 34.8 μm, [Ar II] 6.9 μm, [S III] 18.7 and 33.4 μm were detected in all the starbursts and in ∼80% of the Seyfert 2. Taking under consideration only the PAH bands at 7.7 μm, 11.3 μm, and 12.7 μm, we find that they are present in ∼80% of the Seyfert 1, while only half of this type of activity show the 6.2 μm and 8.6 μm PAH bands. The observed intensity ratios for neutral and ionized PAHs (6.2 μm/7.7 μm x 11.3 μm/7.7 μm) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules (≥180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7 μm) and the neutral PAH bands (8.6 μm and 11.3 μm) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 μm and 11.3 μm bands is nearly constant with the increase of [Ne III]15.5 μm/[Ne II] 12.8 μm, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7 μm) or neutral (11.3 μm) bands, may be destroyed with the increase of the hardness of the radiation field.

40 CFR 1051.103 - What are the exhaust emission standards for snowmobiles?

Science.gov (United States)

2010-07-01

... designed to operate. You must meet the numerical emission standards for hydrocarbons in this section based... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES...

Evaporative and Convective Instabilities for the Evaporation of a Binary Mixture in a Bilayer System

Science.gov (United States)

Guo, Weidong; Narayanan, Ranga

2006-11-01

Evaporative convection in binary mixtures arises in a variety of industrial processes, such as drying of paint and coating technology. There have been theories devoted to this problem either by assuming a passive vapor layer or by isolating the vapor fluid dynamics. Previous work on evaporative and convective instabilities in a single component bilayer system suggests that active vapor layers play a major role in determining the instability of the interface. We have investigated the evaporation convection in binary mixtures taking into account the fluid dynamics of both phases. The liquid mixture and its vapor are assumed to be confined between two horizontal plates with a base state of zero evaporation but with linear vertical temperature profile. When the vertical temperature gradient reaches a critical value, the evaporative instability, Rayleigh and Marangoni convection set in. The effects of vapor and liquid depth, various wave numbers and initial composition of the mixture on the evaporative and convective instability are determined. The physics of the instability are explained and detailed comparison is made between the Rayleigh, Marangoni and evaporative convection in pure component and those in binary mixtures.

Predicting the emissive power of hydrocarbon pool fires

International Nuclear Information System (INIS)

Munoz, Miguel; Planas, Eulalia; Ferrero, Fabio; Casal, Joaquim

2007-01-01

The emissive power (E) of a flame depends on the size of the fire and the type of fuel. In fact, it changes significantly over the flame surface: the zones of luminous flame have high emittance, while those covered by smoke have low E values. The emissive power of each zone (that is, the luminous or clear flame and the non-luminous or smoky flame) and the portion of total flame area they occupy must be assessed when a two-zone model is used. In this study, data obtained from an experimental set-up were used to estimate the emissive power of fires and its behaviour as a function of pool size. The experiments were performed using gasoline and diesel oil as fuel. Five concentric circular pools (1.5, 3, 4, 5 and 6 m in diameter) were used. Appropriate instruments were employed to determine the main features of the fires. By superimposing IR and VHS images it was possible to accurately identify the luminous and non-luminous zones of the fire. Mathematical expressions were obtained that give a more accurate prediction of E lum , E soot and the average emissive power of a fire as a function of its luminous and smoky zones. These expressions can be used in a two-zone model to obtain a better prediction of the thermal radiation. The value of the radiative fraction was determined from the thermal flux measured with radiometers. An expression is also proposed for estimating the radiative fraction

Selective extraction of hydrocarbons, phosphonates and phosphonic acids from soils by successive supercritical fluid and pressurized liquid extractions.

Science.gov (United States)

Chaudot, X; Tambuté, A; Caude, M

2000-01-14

Hydrocarbons, dialkyl alkylphosphonates and alkyl alkylphosphonic acids are selectively extracted from spiked soils by successive implementation of supercritical carbon dioxide, supercritical methanol-modified carbon dioxide and pressurized water. More than 95% of hydrocarbons are extracted during the first step (pure supercritical carbon dioxide extraction) whereas no organophosphorus compound is evidenced in this first extract. A quantitative extraction of phosphonates is achieved during the second step (methanol-modified supercritical carbon dioxide extraction). Polar phosphonic acids are extracted during a third step (pressurized water extraction) and analyzed by gas chromatography under methylated derivatives (diazomethane derivatization). Global recoveries for these compounds are close to 80%, a loss of about 20% occurring during the derivatization process (co-evaporation with solvent). The developed selective extraction method was successfully applied to a soil sample during an international collaborative exercise.

Estimation of evaporative losses during storage of crude oil and petroleum products

Directory of Open Access Journals (Sweden)

Mihajlović Marina A.

2013-01-01

Full Text Available Storage of crude oil and petroleum products inevitably leads to evaporative losses. Those losses are important for the industrial plants mass balances, as well as for the environmental protection. In this paper, estimation of evaporative losses was performed using software program TANKS 409d which was developed by the Agency for Environmental Protection of the United States - US EPA. Emissions were estimated for the following types of storage tanks: fixed conical roof tank, fixed dome roof tank, external floating roof tank, internal floating roof tank and domed external floating roof tank. Obtained results show quantities of evaporated losses per tone of stored liquid. Crude oil fixed roof storage tank losses are cca 0.5 kg per tone of crude oil. For floating roof, crude oil losses are 0.001 kg/t. Fuel oil (diesel fuel and heating oil have the smallest evaporation losses, which are in order of magnitude 10-3 kg/tone. Liquids with higher Reid Vapour Pressure have very high evaporative losses for tanks with fixed roof, up to 2.07 kg/tone. In case of external floating roof tank, losses are 0.32 kg/tone. The smallest losses are for internal floating roof tank and domed external floating roof tank: 0.072 and 0.044, respectively. Finally, it can be concluded that the liquid with low volatility of low BTEX amount can be stored in tanks with fixed roof. In this case, the prevailing economic aspect, because the total amount of evaporative loss does not significantly affect the environment. On the other hand, storage of volatile derivatives with high levels of BTEX is not justified from the economic point of view or from the standpoint of the environment protection.

Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter ...

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% and 30% moisture content on a wet basis) in a forced-draft fan stove, and (iv) wood in a natural-draft rocket cookstove. LPG combustion had the highest thermal efficiency (~57%) and the lowest PAH emissions per unit fuel energy, resulting in the lowest PAH emissions per useful energy delivered (MJd). The average benzo[a]pyrene (B[a]P) emission factor for LPG was 0.842 µg/MJd; the emission rate was 0.043 µg/min. The highest PAH emissions were from wood burning in the natural-draft stove (209-700 µg B[a]P/MJd). PAH emissions from kerosene were significantly lower than those from the wood burning in the natural-draft cookstove, but higher than those from LPG. It is expected that in rural regions where LPG and kerosene are unavailable or unaffordable, the forced-draft fan stove may be an alternative because its emission factor (5.17-8.07 µg B[a]P/MJd) and emission rate (0.52-0.57 µg/min) are similar to kerosene (5.36 µg B[a]P/MJd and 0.45 µg/min). Compared with wood combustion emissions, LPG stoves emit less total PAH emissions and less fractions of high molecular weight PAHs. Relatively large variations in PAH emissions from LPG call for additional future tests to identify the major

Liquid evaporation process and evaporator

International Nuclear Information System (INIS)

Bergey, Claude; Ravenel, Jacques.

1975-01-01

The process described enables a liquid to be evaporated rapidly without any projection. A jet of hot gas is applied to the liquid, the power and angle of the jet being chosen so as to spin the liquid. It is particularly used in the case of radioactive products [fr

A quantum cascade laser infrared spectrometer for CO2 stable isotope analysis: Field implementation at a hydrocarbon contaminated site under bio-remediation.

Science.gov (United States)

Guimbaud, Christophe; Noel, Cécile; Chartier, Michel; Catoire, Valéry; Blessing, Michaela; Gourry, Jean Christophe; Robert, Claude

2016-02-01

Real-time methods to monitor stable isotope ratios of CO2 are needed to identify biogeochemical origins of CO2 emissions from the soil-air interface. An isotope ratio infra-red spectrometer (IRIS) has been developed to measure CO2 mixing ratio with δ(13)C isotopic signature, in addition to mixing ratios of other greenhouse gases (CH4, N2O). The original aspects of the instrument as well as its precision and accuracy for the determination of the isotopic signature δ(13)C of CO2 are discussed. A first application to biodegradation of hydrocarbons is presented, tested on a hydrocarbon contaminated site under aerobic bio-treatment. CO2 flux measurements using closed chamber method is combined with the determination of the isotopic signature δ(13)C of the CO2 emission to propose a non-intrusive method to monitor in situ biodegradation of hydrocarbons. In the contaminated area, high CO2 emissions have been measured with an isotopic signature δ(13)C suggesting that CO2 comes from petroleum hydrocarbon biodegradation. This first field implementation shows that rapid and accurate measurement of isotopic signature of CO2 emissions is particularly useful in assessing the contribution of contaminant degradation to the measured CO2 efflux and is promising as a monitoring tool for aerobic bio-treatment. Copyright © 2016. Published by Elsevier B.V.

An evaporation-based model of thermal neutron induced ternary fission of plutonium

International Nuclear Information System (INIS)

Lestone, J.P.

2008-01-01

Ternary fission probabilities for thermal neutron induced fission of plutonium are analyzed within the framework of an evaporation-based model where the complexity of time-varying potentials, associated with the neck collapse, are included in a simplistic fashion. If the nuclear temperature at scission and the fission-neck-collapse time are assumed to be ~ 1.2 MeV and ~ 10 -22 s, respectively, then calculated relative probabilities of ternary-fission light-charged-particle emission follow the trends seen in the experimental data. The ability of this model to reproduce ternary fission probabilities spanning seven orders of magnitude for a wide range of light-particle charges and masses implies that ternary fission is caused by the coupling of an evaporation-like process with the rapid re-arrangement of the nuclear fluid following scission. (author)

Putting evaporators to work: wiped film evaporator for high level wastes

International Nuclear Information System (INIS)

Dierks, R.D.; Bonner, W.F.

1976-01-01

At Battelle, Pacific Northwest Laboratories, a pilot scale, wiped film evaporator was tested for concentrating high level liquid wastes from Purex-type nuclear fuel recovery processes. The concentrates produced up to 60 wt-percent total solids; and the simplicity of operation and design of the evaporator gave promise for low maintenance and high reliability

Emissions of volatile hydrocarbons (VOC) during drying of sawdust; Utslaepp av laettflyktiga kolvaeten vid torkning av biobraenslen

Energy Technology Data Exchange (ETDEWEB)

Granstroem, Karin

2001-08-01

In the project 'Emissions of volatile hydrocarbons (VOC) during drying of sawdust' the identity, amount and composition of monoterpenes found in the drying medium of a fluidized bed drier drying sawdust from Norwegian spruce and Scotch pine has been determined. The energy efficiency of the drier has also been measured. The aim of this project was to reduce both emissions and energy required for drying, to minimize environmental and health hazards, and make drying more competitive. This would help our primary target group - small scale saw mills - to make use of the sawdust produced as a by- product by making pellets and briquettes. If the VOC remains in the sawdust its energy content will improve and therefore also its value as a fuel. The sawdust was dried to different moisture levels in a spouted bed drier at atmospheric pressure, using either recirculating or not recirculating drying medium with temperatures 140, 170 or 200 deg C. The emissions of VOC were measured using a flame ionization detector (FID) and the nature of the emissions analyzed with a gas chromatograph with mass spectrometric detector (GC-MS). The GC-MS data is reported as emitted substance per oven dry weight (odw). Experiments show that terpenes do not leave the sawdust in great amounts until it is dried to a moisture content (water/total weight) below 10%. When sawdust is dried to a predetermined moisture level, the terpene emissions increase when warmer incoming drying medium is used. The monoterpenes found in greatest amount are a-pinene, b-pinene, 3-carene, limonene and myrcene. y-terpinene was detected in emissions from pine but not from spruce. The relative amounts of different monoterpenes did not vary significantly with post-drying moisture content, but drying medium of higher temperature caused an increase in the relative amount of less volatile monoterpenes. The FID data is reported as concentration of VOC in the drying medium, and as weight VOC per odw. The concentration

Emission reductions through precombustion chamber design in a natural gas, lean burn engine

International Nuclear Information System (INIS)

Crane, M.E.; King, S.R.

1992-01-01

A study was conducted to evaluate the effects of various precombustion chamber design, operating and control parameters on the exhaust emissions of a natural gas engine. Analysis of the results showed that engine-out total hydrocarbons and oxides of nitrogen (NO x ) can be reduced, relative to conventional methods, through prechamber design. More specifically, a novel staged prechamber yielded significant reductions in NO x and total hydrocarbon emissions by promoting stable prechamber and main chamber ignition under fuel-lean conditions. Precise fuel control was also critical when balancing low emissions and engine efficiency (i.e., fuel economy). The purpose of this paper is to identify and explain positive and deleterious effects of natural gas prechamber design on exhaust emissions

Vehicle fleet emissions of black carbon, polycyclic aromatic hydrocarbons, and other pollutants measured by a mobile laboratory in Mexico City

Directory of Open Access Journals (Sweden)

M. Jiang

2005-01-01

Full Text Available Black carbon (BC and polycyclic aromatic hydrocarbons (PAHs are of concern due to their effects on climate and health. The main goal of this research is to provide the first estimate of emissions of BC and particle-phase PAHs (PPAHs from motor vehicles in Mexico City. The emissions of other pollutants including carbon monoxide (CO, oxides of nitrogen (NOx, volatile organic compounds (VOCs, and particulate matter of diameter 2.5 μm and less (PM2.5 are also estimated. As a part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003, a mobile laboratory was driven throughout the city. The laboratory was equipped with a comprehensive suite of gas and particle analyzers, including an aethalometer that measured BC and a photoionization aerosol sensor that measured PPAHs. While driving through traffic, the mobile lab continuously sampled exhaust plumes from the vehicles around it. We have developed a method of automatically identifying exhaust plumes, which are then used as the basis for calculation of fleet-average emissions. In the approximately 75 h of on-road sampling during the field campaign, we have identified ~30 000 exhaust measurement points that represent a variety of vehicle types and driving conditions. The large sample provides a basis for estimating fleet-average emission factors and thus the emission inventory. Motor vehicles in the Mexico City area are estimated to emit 1700±200 metric tons BC, 57±6 tons PPAHs, 1 190 000±40 000 tons CO, 120 000±3000 tons NOx, 240 000±50 000 tons VOCs, and 4400±400 tons PM2.5 per year, not including cold start emissions. The estimates for CO, NOx, and PPAHs may be low by up to 10% due to the slower response time of analyzers used to measure these species. Compared to the government's official motor vehicle emission inventory for the year 2002, the estimates for CO, NOx, VOCs, and PM2.5 are 38% lower, 23% lower, 27% higher, and 25% higher, respectively. The

Trace emissions from gaseous combustion

Energy Technology Data Exchange (ETDEWEB)

Seebold, J.G. [Chevron Research and Technology Co., Richmond, CA (United States)

2000-07-01

The U.S. Clean Air Act (CAA) was amended in 1990 to include the development of maximum achievable control technology (MACT) emission standards for hazardous air pollutants (HAPs) for certain stationary sources by November 2000. MACT emissions standards would affect process heaters and industrial boilers since combustion processes are a potential source for many air toxins. The author noted that one of the problems with MACT is the lack of a clear solid scientific footing which is needed to develop environmentally responsible regulations. In order to amend some of these deficiencies, a 4-year, $7 million research project on the origin and fate of trace emissions in the external combustion of gaseous hydrocarbons was undertaken in a collaborative effort between government, universities and industry. This collaborative project entitled the Petroleum Environmental Research Forum (PERF) Project 92-19 produced basic information and phenomenological understanding in two important areas, one basic and one applied. The specific objectives of the project were to measure emissions while operating different full-scale burners under various operating conditions and then to analyze the emission data to identify which operating conditions lead to low air toxic emissions. Another objective was to develop new chemical kinetic mechanisms and predictive models for the formation of air toxic species which would explain the origin and fate of these species in process heaters and industrial boilers. It was determined that a flame is a very effective reactor and that trace emissions from a typical gas-fired industry burner are very small. An unexpected finding was that trace emissions are not affected by hydrocarbon gaseous fuel composition, nor by the use of ultra low nitrous oxide burners. 2 refs., 8 figs.

Evaporating firewalls

Science.gov (United States)

Van Raamsdonk, Mark

2014-11-01

In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.

Photoluminescence of electron beam evaporated CaS:Bi thin films

CERN Document Server

Smet, P F; Poelman, D R; Meirhaeghe, R L V

2003-01-01

For the first time, the photoluminescence (PL) of electron beam evaporated CaS:Bi thin films is reported. Luminescent CaS:Bi powder prepared out of aqueous solutions was used as source material. The influence of substrate temperature on the PL and the morphology of thin films is discussed, and an optimum is determined. Substrate temperatures between 200 deg. C and 300 deg. C lead to good quality thin films with sufficient PL intensity. As-deposited thin films show two emission bands, peaking at 450 and 530 nm. Upon annealing the emission intensity increases, and annealing at 800 deg. C is sufficient to obtain a homogeneously blue emitting thin film (CIE colour coordinates (0.17; 0.12)), thanks to a single remaining emission band at 450 nm. The influence of ambient temperature on the PL of CaS:Bi powder and thin films was also investigated and it was found that CaS:Bi thin films show a favourable thermal quenching behaviour near room temperature.

Fuel retention in impurity seeded discharges in JET after Be evaporation

International Nuclear Information System (INIS)

Brezinsek, S.; Esser, H.G.; Huber, A.; Kruezi, U.; Philipps, V.; Sergienko, G.; Loarer, T.; Krieger, K.; Eich, T.; McCormick, K.; Jachmich, S.; Tsalas, M.; Coffey, I.; Fundamenski, W.; Giroud, C.; Gruenhagen, S.; Knipe, S.; Maddison, G.P.; Meigs, A.G.; Morgan, Ph.

2011-01-01

Preparatory experiments for the ITER-Like Wall in JET were carried out to simulate the massive Be first wall by a thin Be layer, induced by evaporation of about 2.0 g Be, and to study its impact on fuel retention and divertor radiation with reduced C content and N seeding. Residual gas analysis reveals a reduction of hydrocarbons by one order of magnitude and of O by a factor of 5 in the partial pressure owing to the evaporation. The evolution of wall conditions, impurity fluxes and divertor radiation have been studied in ELMy H-mode plasmas (B t = 2.7 T, I p = 2.5 MA, P aux = 16 MW) whereas a non-seeded reference discharge was executed prior to the evaporation. The in situ measured Be flux at the midplane increased by about a factor of 40 whereas the C flux decreased by ∼50% in the limiter phase of the first discharge with respect to the reference, but erosion of the Be layer and partial coverage with C takes place quickly. To make best use of the protective Be layer, only the first four discharges were employed for a gas balance analysis providing a D retention rate of 1.94 x 10 21 D s -1 which is comparable to rates with C walls. But the Be evaporation provides a non-saturated surface with respect to D and short term retention is not negligible in the balance; the measured retention is overestimated with respect to steady-state conditions like that of the ILW. Moreover, C was only moderately reduced and co-deposition of fuel with eroded Be and C occurs. The lower C content leads to a minor reduction in divertor radiation as the reference phase prior to seeding indicates. N adds to the radiation of D and the remaining C, and the N content rises due to the legacy effect which has been quantified by gas balance to be 30% of the injected N. C radiation increases with exposure time, and both contributors cause an increase in the radiated fraction in the divertor from 50% to 70%. The radiation pattern suggests that N dominates the increase in the first discharges

Analysis of aliphatic and aromatic hydrocarbons in particulate matter in Madrid urban area

International Nuclear Information System (INIS)

Perez, M.; Mendez, J.; Bomboi, M.T.

1988-01-01

Levels of n-alkanes and polycyclic aromatic hydrocarbons have been measured in the air particulate matter during six months, from January to June of 1987, in an urban area of Madrid. The hydrocarbons were collected on glass fiber filters by high volumen sampling. The extraction was carried out by Sohxlet and ultrasonic techniques. The extracts were clean-up on silicagel fractionation and the chromatographic analysis was performed by capillary column gas chromatographic. Final results are discussed as well as the immission values related to the possible emission sources. (Author)

Hydrocarbon-degrading sulfate-reducing bacteria in marine hydrocarbon seep sediments

OpenAIRE

Kleindienst, Sara

2012-01-01

Microorganisms are key players in our biosphere because of their ability to degrade various organic compounds including a wide range of hydrocarbons. At marine hydrocarbon seeps, more than 90% of sulfate reduction (SR) is potentially coupled to non-methane hydrocarbon oxidation. Several hydrocarbon-degrading sulfate-reducing bacteria (SRB) were enriched or isolated from marine sediments. However, in situ active SRB remained largely unknown. In the present thesis, the global distribution and a...

Emissions model of waste treatment operations at the Idaho Chemical Processing Plant

International Nuclear Information System (INIS)

Schindler, R.E.

1995-03-01

An integrated model of the waste treatment systems at the Idaho Chemical Processing Plant (ICPP) was developed using a commercially-available process simulation software (ASPEN Plus) to calculate atmospheric emissions of hazardous chemicals for use in an application for an environmental permit to operate (PTO). The processes covered by the model are the Process Equipment Waste evaporator, High Level Liquid Waste evaporator, New Waste Calcining Facility and Liquid Effluent Treatment and Disposal facility. The processes are described along with the model and its assumptions. The model calculates emissions of NO x , CO, volatile acids, hazardous metals, and organic chemicals. Some calculated relative emissions are summarized and insights on building simulations are discussed

Natural Attenuation of Hydrocarbon and Trichloroethylene Vapors in the Subsurface Environment at Plattsburgh Air Force Base

National Research Council Canada - National Science Library

Ostendorf, David

1997-01-01

.... UMASS tested the hypothesis that natural attenuation processes, stimulated by injected air, reduce emissions of hydrocarbons and trichloroethylene vapors to acceptable air quality standards at the site. Drs...

Evaporation under vacuum condition

International Nuclear Information System (INIS)

Mizuta, Satoshi; Shibata, Yuki; Yuki, Kazuhisa; Hashizume, Hidetoshi; Toda, Saburo; Takase, Kazuyuki; Akimoto, Hajime

2000-01-01

In nuclear fusion reactor design, an event of water coolant ingress into its vacuum vessel is now being considered as one of the most probable accidents. In this report, the evaporation under vacuum condition is evaluated by using the evaporation model we have developed. The results show that shock-wave by the evaporation occurs whose behavior strongly depends on the initial conditions of vacuum. And in the case of lower initial pressure and temperature, the surface temp finally becomes higher than other conditions. (author)

Regulatory off-gas analysis from the evaporation of Hanford simulated waste spiked with organic compounds.

Science.gov (United States)

Saito, Hiroshi H; Calloway, T Bond; Ferrara, Daro M; Choi, Alexander S; White, Thomas L; Gibson, Luther V; Burdette, Mark A

2004-10-01

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, the remaining low-activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation before being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile, and pesticide compounds and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River National Laboratory. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using U.S. Environmental Protection Agency (EPA) SW-846 Methods. Volatile and light semi-volatile organic compounds (1 mm Hg vapor pressure) in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program (licensed by OLI Systems, Inc.) evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate, and off-gas streams, with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI Environmental Simulation Program model is constrained by available literature data.

The bulk isotopic composition of hydrocarbons in subaerial volcanic-hydrothermal emissions from different tectonic settings

Science.gov (United States)

Fiebig, J.; Tassi, F.; Vaselli, O.; Viveiros, M. F.; Silva, C.; Lopez, T. M.; D'Alessandro, W.; Stefansson, A.

2015-12-01

Assuming that methane and its higher chain homologues derive from a common source, carbon isotope patterns have been applied as a criterion to identify occurrences of abiogenic hydrocarbons. Based on these, it has been postulated that abiogenic hydrocarbon production occurs within several (ultra)mafic environments. More evolved volcanic-hydrothermal systems may also provide all the prerequisites necessary for abiogenic hydrocarbon production, such as availability of inorganic CO2, hydrogen and heat. We have investigated the chemical and isotopic composition of n-alkanes contained within subaerial hydrothermal discharges emitted from a range of hot spot, subduction and rift-related volcanoes to determine the origin of hydrocarbons in these systems. Amongst these are Nisyros (Greece), Vesuvio, Campi Flegrei, Ischia, Pantelleria and Vulcano (all Italy), Mt. Mageik and Trident (USA), Copahue (Argentina), Teide (Spain), Furnas and Fogo (Portugal). The carbon isotopic composition of methane emitted from these sites varies from -65 to -8‰ , whereas δ13C of ethane and propane exhibit a much narrower variation from -17‰ to -31‰. Methane that occurs most enriched in 13C is also characterized by relatively positive δD values ranging up to -80‰. Carbon isotope reversals between methane and ethane are only observed for locations exhibiting δ13C-CH4 values > -20‰, such as Teide, Pantelleria, Trident and Furnas. At Furnas, δ13C-CH4 varies by 50‰ within a relatively short distance of <50m between two vents, whereas δ13C-C2H6 varies by less than 2‰ only. For some of the investigated locations apparent carbon isotopic temperatures between methane and CO2 are in agreement with those derived from gas concentration geothermometers. At these locations methane, however seems to be in disequilibrium with ethane and propane. These findings imply that methane on the one hand and the C2+ hydrocarbons on the other hand often might derive from distinct sources.

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan

Directory of Open Access Journals (Sweden)

J. Felden

2013-05-01

Full Text Available The Amon mud volcano (MV, located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

Analysis of a resistance-energy balance method for estimating daily evaporation from wheat plots using one-time-of-day infrared temperature observations

Science.gov (United States)

Choudhury, B. J.; Idso, S. B.; Reginato, R. J.

1986-01-01

Accurate estimates of evaporation over field-scale or larger areas are needed in hydrologic studies, irrigation scheduling, and meteorology. Remotely sensed surface temperature might be used in a model to calculate evaporation. A resistance-energy balance model, which combines an energy balance equation, the Penman-Monteith (1981) evaporation equation, and van den Honert's (1948) equation for water extraction by plant roots, is analyzed for estimating daily evaporation from wheat using postnoon canopy temperature measurements. Additional data requirements are half-hourly averages of solar radiation, air and dew point temperatures, and wind speed, along with reasonable estimates of canopy emissivity, albedo, height, and leaf area index. Evaporation fluxes were measured in the field by precision weighing lysimeters for well-watered and water-stressed wheat. Errors in computed daily evaporation were generally less than 10 percent, while errors in cumulative evaporation for 10 clear sky days were less than 5 percent for both well-watered and water-stressed wheat. Some results from sensitivity analysis of the model are also given.

Evaporation of Lennard-Jones fluids.

Science.gov (United States)

Cheng, Shengfeng; Lechman, Jeremy B; Plimpton, Steven J; Grest, Gary S

2011-06-14

Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature T/T(c), where T(c) is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase.

NOx reduction and NO2 emission characteristics in rich-lean combustion of hydrogen

OpenAIRE

Shudo, Toshio; Omori, Kento; Hiyama, Osamu

2008-01-01

Hydrogen is a clean alternative to conventional hydrocarbon fuels, but it is very important to reduce the nitrogen oxides (NOx) emissions generated by hydrogen combustion. The rich-lean combustion or staged combustion is known to reduce NOx emissions from continuous combustion burners such as gas turbines and boilers, and NOx reduction effects have been demonstrated for hydrocarbon fuels. The authors applied rich-lean combustion to a hydrogen gas turbine and showed its NOx reduction effect in...

Coherence energies in pre-equilibrium emission

International Nuclear Information System (INIS)

De Rosa, A.; Inglima, C.; Perillo, E.; Rosato, E.; Sandoli, M.; Spadaccini, G.

1979-01-01

A method, based on the spectral density analysis, has been developped in order to evaluate coherence of statistical fluctuations. It is specially suitable for reactions showing the contemporary presence of different emission mechanism (e.g. preequilibrium and evaporation - like mechanism)

Simultaneous NOx and hydrocarbon emissions control for lean-burn engines using low-temperature solid oxide fuel cell at open circuit.

Science.gov (United States)

Huang, Ta-Jen; Hsu, Sheng-Hsiang; Wu, Chung-Ying

2012-02-21

The high fuel efficiency of lean-burn engines is associated with high temperature and excess oxygen during combustion and thus is associated with high-concentration NO(x) emission. This work reveals that very high concentration of NO(x) in the exhaust can be reduced and hydrocarbons (HCs) can be simultaneously oxidized using a low-temperature solid oxide fuel cell (SOFC). An SOFC unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3) (LSC)-Ce(0.9)Gd(0.1)O(1.95) as the cathode, with or without adding vanadium to LSC. SOFC operation at 450 °C and open circuit can effectively treat NO(x) over the cathode at a very high concentration in the simulated exhaust. Higher NO(x) concentration up to 5000 ppm can result in a larger NO(x) to N(2) rate. Moreover, a higher oxygen concentration promotes NO conversion. Complete oxidation of HCs can be achieved by adding silver to the LSC current collecting layer. The SOFC-based emissions control system can treat NO(x) and HCs simultaneously, and can be operated without consuming the anode fuel (a reductant) at near the engine exhaust temperature to eliminate the need for reductant refilling and extra heating.

40 CFR 1060.102 - What permeation emission control requirements apply for fuel lines?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What permeation emission control... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY EQUIPMENT Emission Standards and Related Requirements § 1060.102 What permeation...

40 CFR 1060.103 - What permeation emission control requirements apply for fuel tanks?

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What permeation emission control... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY EQUIPMENT Emission Standards and Related Requirements § 1060.103 What permeation...

Film flow analysis for a vertical evaporating tube with inner evaporation and outer condensation

International Nuclear Information System (INIS)

Park, Il Seouk

2008-01-01

A numerical study for the flow, heat and mass transfer characteristics of the evaporating tube with the films flowing down on both the inside and outside tube walls has been carried out. The condensation occurs along the outside wall while the evaporation occurs at the free surface of the inside film. The transport equations for momentum and energy are parabolized by the boundary-layer approximation and solved by using the marching technique. The calculation domain of 2 film flow regions (evaporating and condensation films at the inside and outside tube wall respectively) and tube wall is solved simultaneously. The coupling technique for the problem with the 3 different regions and the 2 interfaces of them has been developed to calculated the temperature field. The velocity and temperature fields and the amount of the condensed and evaporated mass as well as the position where the evaporating film is completely dried out are successfully predicted for various inside pressures and inside film inlet flow rates

THE USE OF POROUS CERAMICS FOR EVAPORATIVE AND EVAPORATIVE – VAPOR –COMPRESSION SYSTEMS

Directory of Open Access Journals (Sweden)

Cheban D.N.

2013-04-01

Full Text Available The use of natural evaporative cooling is one of technical solutions of problem of energy efficiency in air conditioning systems. The use of evaporative cooling in the first combined cooling stage allows reducing the load on the condenser of the cooling machine due to reducing of the condensing temperature. This combination allows the use of this type of system in any climatic conditions, including regions with small water resources. Multi-porous ceramic structure is used in evaporative air coolers and water coolers in this case. The objective of this paper is to show advantages of the using of porous ceramic as a working attachment, and to show advantages of the proposed scheme of compression-evaporation systems in comparison with standard vapor compression systems. Experimental research proved the fact, that in the film mode cooling efficiency of air flow is between EA=0,6÷0,7 and is slightly dependent of water flow. For countries with hot and dry climate where reserves of water are limited, it is recommended to use cyclical regime with EA≈0,65 value, or to use channel regime with a value of EA≈0,55. This leads to considerable energy savings. It has been determined, that combined air conditioning system is completely closed on the consumption of water at the parameters of the outside air equal to tA =32ºC and XA>13g/kg (in system with direct evaporative cooling machine, and tA=32ºC and XA>12g/kg (in system with indirect evaporative cooling machine. With these parameters, the cost of water in evaporative cooling stage can be fully compensated by condensate from the evaporator chiller.

CHROMOSPHERIC EVAPORATION IN AN X1.0 FLARE ON 2014 MARCH 29 OBSERVED WITH IRIS AND EIS

Energy Technology Data Exchange (ETDEWEB)

Li, Y.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Qiu, J. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Cheng, J. X., E-mail: yingli@nju.edu.cn [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)

2015-09-20

Chromospheric evaporation refers to dynamic mass motions in flare loops as a result of rapid energy deposition in the chromosphere. These motions have been observed as blueshifts in X-ray and extreme-ultraviolet (EUV) spectral lines corresponding to upward motions at a few tens to a few hundreds of km s{sup −1}. Past spectroscopic observations have also revealed a dominant stationary component, in addition to the blueshifted component, in emission lines formed at high temperatures (∼10 MK). This is contradictory to evaporation models predicting predominant blueshifts in hot lines. The recently launched Interface Region Imaging Spectrograph (IRIS) provides high-resolution imaging and spectroscopic observations that focus on the chromosphere and transition region in the UV passband. Using the new IRIS observations, combined with coordinated observations from the EUV Imaging Spectrometer, we study the chromospheric evaporation process from the upper chromosphere to the corona during an X1.0 flare on 2014 March 29. We find evident evaporation signatures, characterized by Doppler shifts and line broadening, at two flare ribbons that are separating from each other, suggesting that chromospheric evaporation takes place in successively formed flaring loops throughout the flare. More importantly, we detect dominant blueshifts in the high-temperature Fe xxi line (∼10 MK), in agreement with theoretical predictions. We also find that, in this flare, gentle evaporation occurs at some locations in the rise phase of the flare, while explosive evaporation is detected at some other locations near the peak of the flare. There is a conversion from gentle to explosive evaporation as the flare evolves.

DWPF Recycle Evaporator Simulant Tests

International Nuclear Information System (INIS)

Stone, M

2005-01-01

Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming, scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to

Towards efficient next generation light sources: combined solution processed and evaporated layers for OLEDs

Science.gov (United States)

Hartmann, D.; Sarfert, W.; Meier, S.; Bolink, H.; García Santamaría, S.; Wecker, J.

2010-05-01

Typically high efficient OLED device structures are based on a multitude of stacked thin organic layers prepared by thermal evaporation. For lighting applications these efficient device stacks have to be up-scaled to large areas which is clearly challenging in terms of high through-put processing at low-cost. One promising approach to meet cost-efficiency, high through-put and high light output is the combination of solution and evaporation processing. Moreover, the objective is to substitute as many thermally evaporated layers as possible by solution processing without sacrificing the device performance. Hence, starting from the anode side, evaporated layers of an efficient white light emitting OLED stack are stepwise replaced by solution processable polymer and small molecule layers. In doing so different solutionprocessable hole injection layers (= polymer HILs) are integrated into small molecule devices and evaluated with regard to their electro-optical performance as well as to their planarizing properties, meaning the ability to cover ITO spikes, defects and dust particles. Thereby two approaches are followed whereas in case of the "single HIL" approach only one polymer HIL is coated and in case of the "combined HIL" concept the coated polymer HIL is combined with a thin evaporated HIL. These HIL architectures are studied in unipolar as well as bipolar devices. As a result the combined HIL approach facilitates a better control over the hole current, an improved device stability as well as an improved current and power efficiency compared to a single HIL as well as pure small molecule based OLED stacks. Furthermore, emitting layers based on guest/host small molecules are fabricated from solution and integrated into a white hybrid stack (WHS). Up to three evaporated layers were successfully replaced by solution-processing showing comparable white light emission spectra like an evaporated small molecule reference stack and lifetime values of several 100 h.

40 CFR 1048.105 - What evaporative emission standards and requirements apply?

Science.gov (United States)

2010-07-01

... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD SPARK-IGNITION... specified in § 1048.501. Diurnal emission controls must continue to function during engine operation. (d... 62 kPa (9 psi) begins to boil at about 53 °C at atmospheric pressure, and at about 60 °C for fuel...

Evaporation from a temperate closed-basin lake and its impact on present, past, and future water level

Science.gov (United States)

Xiao, K.; Griffis, T. J.; Baker, J. M.; Bolstad, P. V.; Erickson, M. D.; Lee, X.; Wood, J. D.; Hu, C.

2017-12-01

Lakes provide enormous economic, recreational, and aesthetic benefits to citizens. These ecosystem services may be adversely impacted by climate change. In the Twin Cities Metropolitan Area of Minnesota, USA, many lakes have been at historic low levels and water augmentation strategies have been proposed to alleviate the problem. For example, the water level of White Bear Lake (WBL) declined 1.5 m during 2003-2013 for reasons that are not fully understood. This study examined current, past, and future lake evaporation to better understand how climate will impact the water balance of lakes within this region. Evaporation from WBL was measured from July 2014 to February 2017 using two eddy covariance (EC) systems to provide better constraints on the water budget and to investigate the impact of evaporation on lake level. The annual evaporation for years 2014 through 2016 were 559±22 mm, 779±81 mm, and 766±11 mm, respectively. The larger evaporation in 2015 and 2016 was caused by the combined effects of larger average daily evaporation and a longer ice-free season. The EC measurements were used to tune the Community Land Model 4 - Lake, Ice, Snow and Sediment Simulator (CLM4-LISSS) to estimate lake evaporation over the period 1979-2016. Retrospective analyses indicated that WBL evaporation increased by about 3.8 mm yr-1. Mass balance analysis implied that the lake level declines at WBL during 1986-1990 and 2003-2012 were mainly caused by the coupled low precipitation and high evaporation. Using a business-as-usual greenhouse gas emission scenario (RCP8.5), lake evaporation was modeled forward in time from 2017 to 2100. Annual evaporation is expected to increase by 1.4 mm yr-1 over this century, which is largely driven by lengthening ice-free periods. These changes in ice phenology and evaporation will have important implications for the regional water balance, and water management and water augmentation strategies that are being proposed for these Metropolitan

Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop

Science.gov (United States)

Tan, Huanshu; Diddens, Christian; Lv, Pengyu; Kuerten, J. G. M.; Zhang, Xuehua; Lohse, Detlef

2016-01-01

Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even liquid mixtures has intensively been studied over the past two decades, the evaporation of ternary mixtures of liquids with different volatilities and mutual solubilities has not yet been explored. Here we show that the evaporation of such ternary mixtures can trigger a phase transition and the nucleation of microdroplets of one of the components of the mixture. As a model system, we pick a sessile Ouzo droplet (as known from daily life—a transparent mixture of water, ethanol, and anise oil) and reveal and theoretically explain its four life phases: In phase I, the spherical cap-shaped droplet remains transparent while the more volatile ethanol is evaporating, preferentially at the rim of the drop because of the singularity there. This leads to a local ethanol concentration reduction and correspondingly to oil droplet nucleation there. This is the beginning of phase II, in which oil microdroplets quickly nucleate in the whole drop, leading to its milky color that typifies the so-called “Ouzo effect.” Once all ethanol has evaporated, the drop, which now has a characteristic nonspherical cap shape, has become clear again, with a water drop sitting on an oil ring (phase III), finalizing the phase inversion. Finally, in phase IV, all water has evaporated, leaving behind a tiny spherical cap-shaped oil drop. PMID:27418601

Field electron emission spectrometer combined with field ion/electron microscope as a field emission laboratory

International Nuclear Information System (INIS)

Shkuratov, S.I.; Ivanov, S.N.; Shilimanov, S.N.

1996-01-01

The facility, combining the field ion microscope, field electron emission microscope and field electron emission spectrometer, is described. Combination of three methodologies makes it possible to carry out the complete cycle of emission studies. Atom-plane and clean surface of the studied samples is prepared by means of field evaporation of the material atom layers without any thermal and radiation impact. This enables the study of atom and electron structure of clean surface of the wide range materials, the study whereof through the field emission methods was previously rather difficult. The temperature of the samples under study changes from 75 up to 2500 K. The energy resolution of the electron analyzer equals 30 MeV. 19 refs., 10 figs

Observation and Modeling of Chromospheric Evaporation in a Coronal Loop Related to Active Region Transient Brightening

Science.gov (United States)

Gupta, G. R.; Sarkar, Aveek; Tripathi, Durgesh

2018-04-01

Using the observations recorded by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory and the Interface Region Imaging Spectrograph (IRIS) and the Extreme-ultraviolet Imaging Spectrometer and X-Ray Telescope both on board Hinode, we present evidence of chromospheric evaporation in a coronal loop after the occurrence of two active region transient brightenings (ARTBs) at the two footpoints. The chromospheric evaporation started nearly simultaneously in all of the three hot channels of AIA 131, 94, and 335 Å and was observed to be temperature dependent, being fastest in the highest temperature channel. The whole loop became fully brightened following the ARTBs after ≈25 s in 131 Å, ≈40 s in 94 Å, and ≈6.5 minutes in 335 Å. The differential emission measurements at the two footpoints (i.e., of two ARTBs) and at the loop top suggest that the plasma attained a maximum temperature of ∼10 MK at all these locations. The spectroscopic observations from IRIS revealed the presence of redshifted emission of ∼20 km s‑1 in cooler lines like C II and Si IV during the ARTBs that was cotemporal with the evaporation flow at the footpoint of the loop. During the ARTBs, the line width of C II and Si IV increased nearly by a factor of two during the peak emission. Moreover, enhancement in the line width preceded that in the Doppler shift, which again preceded enhancement in the intensity. The observed results were qualitatively reproduced by 1D hydrodynamic simulations, where energy was deposited at both of the footpoints of a monolithic coronal loop that mimicked the ARTBs identified in the observations.

Impact of using fishing boat fuel with high poly aromatic content on the emission of polycyclic aromatic hydrocarbons from the diesel engine

Science.gov (United States)

Lin, Yuan-Chung; Lee, Wen-Jhy; Li, Hsing-Wang; Chen, Chung-Ban; Fang, Guor-Cheng; Tsai, Perng-Jy

Because of the fishery subsidy policy, the fishing boat fuel oil (FBFO) exemption from commodity taxes, business taxes and air pollution control fees, resulted in the price of FBFO was ˜50% lower than premium diesel fuel (PDF) in Taiwan. It is estimated that ˜650,000 kL FBFO was illegally used by traveling diesel-vehicles (TDVs) with a heavy-duty diesel engine (HDDE), which accounted for ˜16.3% of the total diesel fuel consumed by TDVs. In this study, sulfur, poly aromatic and total-aromatic contents in both FBFO and PDF were measured and compared. Exhaust emissions of polycyclic aromatic hydrocarbons (PAHs) and their carcinogenic potencies (BaP eq) from a HDDE under transient cycle testing for both FBFO and PDF were compared and discussed. Finally, the impact caused by the illegal use of FBFO on the air quality was examined. Results show that the mean sulfur-, poly aromatic and aromatic-contents in FBFO were 43.0, 3.89 and 1.04 times higher than that of PDF, respectively. Emission factors of total-PAHs and total-BaP eq obtained by utilizing FBFO were 51.5 and 0.235 mg L -1-Fuel, which were 3.41 and 5.82 times in magnitude higher than obtained by PDF, respectively. The estimated annual emissions of total-PAHs and total-BaP eq to the ambient environment due to the illegally used FBFO were 23.6 and 0.126 metric tons, respectively, which resulted in a 17.9% and a 25.0% increment of annual emissions from all mobile sources, respectively. These results indicated that the FBFO used illegally by TDVs had a significant impact on PAH emissions to the ambient environment.

Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

Energy Technology Data Exchange (ETDEWEB)

Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

2016-04-01

Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

The identification and characterization of osmotolerant yeast isolates from chemical wastewater evaporation ponds.

Science.gov (United States)

Lahav, R; Fareleira, P; Nejidat, A; Abeliovich, A

2002-04-01

Ramat Hovav is a major chemical industrial park manufacturing pharmaceuticals, pesticides, and various aliphatic and aromatic halogens. All wastewater streams are collected in large evaporation ponds. Salinity in the evaporation ponds fluctuates between 3% (w/v) and saturation and pH values range between 2.0 and 10.0. We looked for microorganisms surviving in these extreme environmental conditions and found that 2 yeast strains dominate this biotope. 18S rDNA sequence analysis identified the isolates as Pichia guilliermondii and Rhodotorula mucilaginosa. Both isolates grew in NaCl concentrations ranging up to 3.5 M and 2.5 M, respectively, and at a pH range of 2-10. There was a distinct difference between the Rhodotorula and Pichia strains and S. cerevisiae RS16 that served as a control strain with respect to accumulation of osmoregulators and internal ion concentrations when exposed to osmotic stress. The Pichia and Rhodotorula strains maintained high glycerol concentration also in media low in NaCl. Utilization of various carbon sources was examined. Using a tetrazolium-based assay we show that the Rhodotorula and Pichia strains are capable of utilizing a wide range of different carbon sources including anthracene, phenanthrene, and other cyclic aromatic hydrocarbons.

Regulated and unregulated emissions from modern 2010 emissions-compliant heavy-duty on-highway diesel engines.

Science.gov (United States)

Khalek, Imad A; Blanks, Matthew G; Merritt, Patrick M; Zielinska, Barbara

2015-08-01

The U.S. Environmental Protection Agency (EPA) established strict regulations for highway diesel engine exhaust emissions of particulate matter (PM) and nitrogen oxides (NOx) to aid in meeting the National Ambient Air Quality Standards. The emission standards were phased in with stringent standards for 2007 model year (MY) heavy-duty engines (HDEs), and even more stringent NOX standards for 2010 and later model years. The Health Effects Institute, in cooperation with the Coordinating Research Council, funded by government and the private sector, designed and conducted a research program, the Advanced Collaborative Emission Study (ACES), with multiple objectives, including detailed characterization of the emissions from both 2007- and 2010-compliant engines. The results from emission testing of 2007-compliant engines have already been reported in a previous publication. This paper reports the emissions testing results for three heavy-duty 2010-compliant engines intended for on-highway use. These engines were equipped with an exhaust diesel oxidation catalyst (DOC), high-efficiency catalyzed diesel particle filter (DPF), urea-based selective catalytic reduction catalyst (SCR), and ammonia slip catalyst (AMOX), and were fueled with ultra-low-sulfur diesel fuel (~6.5 ppm sulfur). Average regulated and unregulated emissions of more than 780 chemical species were characterized in engine exhaust under transient engine operation using the Federal Test Procedure cycle and a 16-hr duty cycle representing a wide dynamic range of real-world engine operation. The 2010 engines' regulated emissions of PM, NOX, nonmethane hydrocarbons, and carbon monoxide were all well below the EPA 2010 emission standards. Moreover, the unregulated emissions of polycyclic aromatic hydrocarbons (PAHs), nitroPAHs, hopanes and steranes, alcohols and organic acids, alkanes, carbonyls, dioxins and furans, inorganic ions, metals and elements, elemental carbon, and particle number were substantially (90

242-A evaporator safety analysis report

International Nuclear Information System (INIS)

CAMPBELL, T.A.

1999-01-01

This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR

242-A evaporator safety analysis report

Energy Technology Data Exchange (ETDEWEB)

CAMPBELL, T.A.

1999-05-17

This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR.

Emissions deterioration for three alternative fuel vehicle types: Natural gas, ethanol, and methanol vehicles

International Nuclear Information System (INIS)

Winebrake, J.J.; Deaton, M.L.

1997-01-01

Although there have been several studies examining emissions from in-use alternative fuel vehicles (AFVs), little is known about the deterioration of these emissions over vehicle lifetimes and how this deterioration compares with deterioration from conventional vehicles (CVs). This paper analyzes emissions data from 70 AFVs and 70 CVs operating in the federal government fleet to determine whether AFV emissions deterioration differs significantly from CV emissions deterioration. The authors conduct the analysis on three alternative fuel types (natural gas, methanol, and ethanol) and on five pollutants (carbon monoxide, carbon dioxide, total hydrocarbons, non-methane hydrocarbons, and nitrogen oxides). They find that for most cases they studied, deterioration differences are not statistically significant; however, several exceptions suggest that air quality planners and regulators must further analyze AFV emissions deterioration in order to properly include these technologies into broader air quality management schemes

Chemical storage of renewable electricity in hydrocarbon fuels via H{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Eilers, H.; Iglesias Gonzalez, M.; Schaub, G. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Engler-Bunte-Institute I

2012-07-01

The increased generation of renewable electricity leads to an increasing demand for storage due to its fluctuating production. Electrical energy can be stored as chemical energy carriers e.g. in form of H{sub 2} that can be further processed to hydrocarbons. Storage in form of hydrocarbons is advantageous compared to H{sub 2} storage since (i) a higher volumetric energy density in the product can be achieved and (ii) the infrastructure for hydrocarbon distribution, storage and utilization already exists. The present contribution introduces the potential of H{sub 2} integration in upgrading/production processes to hydrocarbon fuels, based on stoichiometry and kind of carbon feedstock. Processes include petroleum refining, vegetable oil hydrogenation, production of synfuel from lignocellulosic biomass and substitute natural gas from H{sub 2}/CO{sub 2}. In the case of fossil raw materials, yields per feedstock can be increased and fossil CO{sub 2} emissions decreased since fossil resources for H{sub 2} production can be avoided. In the case of biomass conversion to synfuels, product yields per biomass/hectare can be increased. If CO{sub 2} is hydrogenated to fuels, no gasification step is needed, however lower hydrocarbon product yields per H{sub 2} are achieved since CO{sub 2} has the highest oxygen content. (orig.)

In-line high-rate evaporation of aluminum for the metallization of silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Mader, Christoph Paul

2012-07-11

This work focuses on the in-line high-rate evaporation of aluminum for contacting rear sides of silicon solar cells. The substrate temperature during the deposition process, the wafer bow after deposition, and the electrical properties of evaporated contacts are investigated. Furthermore, this work demonstrates for the first time the formation of aluminum-doped silicon regions by the in-line high-rate evaporation of aluminum without any further temperature treatment. The temperature of silicon wafers during in-line high-rate evaporation of aluminum is investigated in this work. The temperatures are found to depend on the wafer thickness W, the aluminum layer thickness d, and on the wafer emissivity {epsilon}. Two-dimensional finite-element simulations reproduce the measured peak temperatures with an accuracy of 97%. This work also investigates the wafer bow after in-line high-rate evaporation and shows that the elastic theory overestimates the wafer bow of planar Si wafers. The lower bow is explained with plastic deformation in the Al layer. Due to the plastic deformation only the first 79 K in temperature decrease result in a bow formation. Furthermore the electrical properties of evaporated point contacts are examined in this work. Parameterizations for the measured saturation currents of contacted p-type Si wafers and of contacted boron-diffused p{sup +}-type layers are presented. The contact resistivity of the deposited Al layers to silicon for various deposition processes and silicon surface concentrations are presented and the activation energy of the contact formation is determined. The measured saturation current densities and contact resistivities of the evaporated contacts are used in one-dimensional numerical Simulations and the impact on energy conversion efficiency of replacing a screen-printed rear side by an evaporated rear side is presented. For the first time the formation of aluminum-doped p{sup +}-type (Al-p{sup +}) silicon regions by the in

Assessing Energy Efficiency of Compression Heat Pumps in Drying Processes when Zeotropic Hydrocarbon Mixtures are Used as Working Agents

Directory of Open Access Journals (Sweden)

Shurayts Alexander

2016-01-01

Full Text Available Presents the results of studies of innovative materials in the field of renewable energy.The paper proposes a design and a formula for assessing energy efficiency of the heat pump air dryer, which uses zeotropic hydrocarbon mixtures of saturated hydrocarbons as a working agent and applies the principle of a counter-current heat exchanger with a variable temperature of both the working and the drying agents. Energy efficiency of the heat pump is achieved by means of obtaining a greater part of heat from renewable energy sources, in this case by cooling the air and condensing the water vapors in the heat pump. A conducted analysis identified correlations in establishing the marginal real coefficient of performance of the compression heat pump dryer running on zeotropic hydrocarbon mixtures and operating a cycle with variable temperatures of both the working and the drying agent in the evaporator and the condenser of the heat pump. According to the established correlations, the marginal real coefficient of performance of the compression heat pump dryers running on zeotropic hydrocarbon mixtures of 40 mol% of R600a and 60 mol% of R601 is 1.92 times higher than that of the same dryers running on only R600 (n-butane.

Biodegradation studies of oil sludge containing high hydrocarbons concentration

International Nuclear Information System (INIS)

Olguin-Lora, P.; Munoz-Colunga, A.; Castorena-Cortes, G.; Roldan-Carrillo, T.; Quej Ake, L.; Reyes-Avila, J.; Zapata-Penasco, I.; Marin-Cruz, J.

2009-01-01

Oil industry has a significant impact on environment due to the emission of, dust, gases, waste water and solids generated during oil production all the way to basic petrochemical product manufacturing stages. the aim of this work was to evaluate the biodegradation of sludge containing high hydrocarbon concentration originated by a petroleum facility. A sludge sampling was done at the oil residuals pool (ORP) on a gas processing center. (Author)

Technical and environmental analysis of biofuel dryers; Teknisk och miljoemaessig analys av biobraensletorkar

Energy Technology Data Exchange (ETDEWEB)

Muenter, M; Hagman, U; Harnevie, H; Johansen, H; Kristensson, I; Westermark, M; Viberg, T [Vattenfall Energimarknad, Stockholm (Sweden)

1999-03-01

A study regarding technology and environmental impact of the drying process of biofuels has been conducted. In the study two different types of dryers are analyzed. The result from the study shows that emissions of primarily hydrocarbons is high from the direct technic. The emission can be decreased considerably by improving the burner of the dryer. For the indirect technic the evaporated water give rise to problems in the sewage treatment plant. Studies show that biological treatment will result in an acceptable condensate.

Chemistry of Volatile Organic Compounds in the Los Angeles basin: Nighttime Removal of Alkenes and Determination of Emission Ratios

Science.gov (United States)

de Gouw, J. A.; Gilman, J. B.; Kim, S.-W.; Lerner, B. M.; Isaacman-VanWertz, G.; McDonald, B. C.; Warneke, C.; Kuster, W. C.; Lefer, B. L.; Griffith, S. M.; Dusanter, S.; Stevens, P. S.; Stutz, J.

2017-11-01

We reanalyze a data set of hydrocarbons in ambient air obtained by gas chromatography-mass spectrometry at a surface site in Pasadena in the Los Angeles basin during the NOAA California Nexus study in 2010. The number of hydrocarbon compounds quantified from the chromatograms is expanded through the use of new peak-fitting data analysis software. We also reexamine hydrocarbon removal processes. For alkanes, small alkenes, and aromatics, the removal is determined by the reaction with hydroxyl (OH) radicals. For several highly reactive alkenes, the nighttime removal by ozone and nitrate (NO3) radicals is also significant. We discuss how this nighttime removal affects the determination of emission ratios versus carbon monoxide (CO) and show that previous estimates based on nighttime correlations with CO were too low. We analyze model output from the Weather Research and Forecasting-Chemistry model for hydrocarbons and radicals at the Pasadena location to evaluate our methods for determining emission ratios from the measurements. We find that our methods agree with the modeled emission ratios for the domain centered on Pasadena and that the modeled emission ratios vary by 23% across the wider South Coast basin. We compare the alkene emission ratios with published results from ambient measurements and from tunnel and dynamometer studies of motor vehicle emissions. We find that with few exceptions the composition of alkene emissions determined from the measurements in Pasadena closely resembles that of motor vehicle emissions.

Studies of 4He emission in both fusion-like and inelastic reactions of 340-MeV 40Ar + 238U

International Nuclear Information System (INIS)

Kildir, M.; Logan, D.; Kaplan, M.; Zisman, M.S.; Guerreau, D.; Alexander, J.M.; Vaz, L.C.

1982-01-01

The fission-fragment angular correlation technique has been used in conjunction with a position-sensitive avalanche detector to identify the fusion-like and inelastic collisions of 340-MeV 40 Ar + 238 U. For each of these two reaction types, we have characterized the correlated 4 He emission by measuring three-fold coincidences between two fission fragments and the light charged particle. We find an abundance of both evaporation-like and direct 4 He emission, each of which is associated with both fusion-fission and sequential-fission processes. Several comparison tests of both the coincidence and singles data strongly indicate that very little 4 He emission is due to evaporation from accelerated fission fragments in this system. The evaporative 4 He emission appears instead to have a strong contribution originating from the composite system prior to fission. The forward angle 4 He emissions, characterized by prominent forward-peaking and relatively high energies, suggest an origin associated with the very early stages of the collision

Study of electron-beam-evaporated MgO films using electron diffraction, optical absorption and cathodoluminescence

Energy Technology Data Exchange (ETDEWEB)

Aboelfotoh, M.O.; Ramsey, J.N.

1982-05-21

Reflection high energy electron diffraction, optical absorption and cathodoluminescence were used to study MgO films deposited onto fused silica, single-crystal silicon and LiF substrates at various temperatures. Results showed that some of the same optical absorption and emission bands observed in X- or UV-irradiated, additively colored or mechanically deformed MgO crystals were observed in evaporated MgO films. The peak positions and the relative peak intensities of the optical absorption and emission bands depended on the substrate temperature during film deposition as well as on the structure of the film. The effect of heating the films in air and vacuum on the optical absorption and emission bands is also discussed.

Evaporation from a temperate closed-basin lake and its impact on present, past, and future water level

Science.gov (United States)

Xiao, Ke; Griffis, Timothy J.; Baker, John M.; Bolstad, Paul V.; Erickson, Matt D.; Lee, Xuhui; Wood, Jeffrey D.; Hu, Cheng; Nieber, John L.

2018-06-01

Lakes provide enormous economic, recreational, and aesthetic benefits to citizens. These ecosystem services may be adversely impacted by climate change. In the Twin Cities Metropolitan Area of Minnesota, USA, many lakes have been at historic low levels and water augmentation strategies have been proposed to alleviate the problem. White Bear Lake (WBL) is a notable example. Its water level declined 1.5 m during 2003-2013 for reasons that are not fully understood. This study examined current, past, and future lake evaporation to better understand how climate will impact the water balance of lakes within this region. Evaporation from WBL was measured from July 2014 to February 2017 using two eddy covariance (EC) systems to provide better constraints on the water budget and to investigate the impact of evaporation on lake level. The estimated annual evaporation losses for years 2014 through 2016 were 559 ± 22 mm, 779 ± 81 mm, and 766 ± 11 mm, respectively. The higher evaporation in 2015 and 2016 was caused by the combined effects of larger average daily evaporation and a longer ice-free season. The EC measurements were used to tune the Community Land Model 4 - Lake, Ice, Snow and Sediment Simulator (CLM4-LISSS) to estimate lake evaporation over the period 1979-2016. Retrospective analyses indicate that WBL evaporation increased during this time by about 3.8 mm year-1, which was driven by increased wind speed and lake-surface vapor pressure gradient. Using a business-as-usual greenhouse gas emission scenario (RCP8.5), lake evaporation was modeled forward in time from 2017 to 2100. Annual evaporation is expected to increase by 1.4 mm year-1 over this century, largely driven by lengthening ice-free periods. These changes in ice phenology and evaporation will have important implications for the regional water balance, and water management and water augmentation strategies that are being proposed for these Metropolitan lakes.

Evaporation Kinetics of Polyol Droplets: Determination of Evaporation Coefficients and Diffusion Constants

Science.gov (United States)

Su, Yong-Yang; Marsh, Aleksandra; Haddrell, Allen E.; Li, Zhi-Ming; Reid, Jonathan P.

2017-11-01

In order to quantify the kinetics of mass transfer between the gas and condensed phases in aerosol, physicochemical properties of the gas and condensed phases and kinetic parameters (mass/thermal accommodation coefficients) are crucial for estimating mass fluxes over a wide size range from the free molecule to continuum regimes. In this study, we report measurements of the evaporation kinetics of droplets of 1-butanol, ethylene glycol (EG), diethylene glycol (DEG), and glycerol under well-controlled conditions (gas flow rates and temperature) using the previously developed cylindrical electrode electrodynamic balance technique. Measurements are compared with a model that captures the heat and mass transfer occurring at the evaporating droplet surface. The aim of these measurements is to clarify the discrepancy in the reported values of mass accommodation coefficient (αM, equals to evaporation coefficient based on microscopic reversibility) for 1-butanol, EG, and DEG and improve the accuracy of the value of the diffusion coefficient for glycerol in gaseous nitrogen. The uncertainties in the thermophysical and experimental parameters are carefully assessed, the literature values of the vapor pressures of these components are evaluated, and the plausible ranges of the evaporation coefficients for 1-butanol, EG, and DEG as well as uncertainty in diffusion coefficient for glycerol are reported. Results show that αM should be greater than 0.4, 0.2, and 0.4 for EG, DEG, and 1-butanol, respectively. The refined values are helpful for accurate prediction of the evaporation/condensation rates.

Lake Nasser evaporation reduction study

Directory of Open Access Journals (Sweden)

Hala M.I. Ebaid

2010-10-01

Full Text Available This study aims to evaluate the reduction of evaporation of Lake Nasser’s water caused by disconnecting (fully or partially some of its secondary channels (khors. This evaluation integrates remote sensing, Geographic Information System (GIS techniques, aerodynamic principles, and Landsat7 ETM+ images. Three main procedures were carried out in this study; the first derived the surface temperature from Landsat thermal band; the second derived evaporation depth and approximate evaporation volume for the entire lake, and quantified evaporation loss to the secondary channels’ level over one month (March by applied aerodynamic principles on surface temperature of the raster data; the third procedure applied GIS suitability analysis to determine which of these secondary channels (khors should be disconnected. The results showed evaporation depth ranging from 2.73 mm/day at the middle of the lake to 9.58 mm/day at the edge. The evaporated water-loss value throughout the entire lake was about 0.86 billion m3/month (March. The analysis suggests that it is possible to save an approximate total evaporation volume loss of 19.7 million m3/month (March, and thus 2.4 billion m3/year, by disconnecting two khors with approximate construction heights of 8 m and 15 m. In conclusion, remote sensing and GIS are useful for applications in remote locations where field-based information is not readily available and thus recommended for decision makers remotely planning in water conservation and management.

Concept for lowest emissions of a hydrogen internal combustion engine; Niedrigstemissionskonzept fuer einen wasserstoffbetriebenen Verbrennungsmotor

Energy Technology Data Exchange (ETDEWEB)

Fouquet, Marcel Christian Thomas

2012-03-15

This paper describes a concept with lowest emissions for a hydrogen internal combustion engine for passenger cars. With optimisation of the combustion concept the level of nitrogen oxide is below 90%, hydrocarbon and carbon monoxide below 99% of the SULEV target (CARB). This concept enables a potential in power density that is comparable to current supercharged combustion engines at lowest emission level without catalytic aftertreatment. Additionally with a catalytic aftertreatment system, the emission level of a current hydrogen combustion engine (mono-fuel) is lowered to a level, that this car can be labeled as air cleaning vehicle for hydrocarbons and carbon monoxide.

Behavior of sulfur mustard in sand, concrete, and asphalt matrices: Evaporation, degradation, and decontamination.

Science.gov (United States)

Jung, Hyunsook; Choi, Seungki

2017-10-15

The evaporation, degradation, and decontamination of sulfur mustard on environmental matrices including sand, concrete, and asphalt are described. A specially designed wind tunnel and thermal desorber in combination with gas chromatograph (GC) produced profiles of vapor concentration obtained from samples of the chemical agent deposited as a drop on the surfaces of the matrices. The matrices were exposed to the chemical agent at room temperature, and the degradation reactions were monitored and characterized. A vapor emission test was also performed after a decontamination process. The results showed that on sand, the drop of agent spread laterally while evaporating. On concrete, the drop of the agent was absorbed immediately into the matrix while spreading and evaporating. However, the asphalt surface conserved the agent and slowly released parts of the agent over an extended period of time. The degradation reactions of the agent followed pseudo first order behavior on the matrices. Trace amounts of the residual agent present at the surface were also released as vapor after decontamination, posing a threat to the exposed individual and environment.

77 FR 16547 - Radionuclide National Emission Standards for Hazardous Air Pollutants; Notice of Construction...

Science.gov (United States)

2012-03-21

... Construction Approval to Energy Fuels for Tailings Cell A and the Phase I Evaporation Ponds at the proposed Pi[ntilde]on Ridge Uranium Mill. Tailings Cell A and the Phase I Evaporation Ponds are regulated under 40... ENVIRONMENTAL PROTECTION AGENCY [FRL-9649-9] Radionuclide National Emission Standards for...

The evaporative vector: Homogeneous systems

International Nuclear Information System (INIS)

Klots, C.E.

1987-05-01

Molecular beams of van der Waals molecules are the subject of much current research. Among the methods used to form these beams, three-sputtering, laser ablation, and the sonic nozzle expansion of neat gases - yield what are now recognized to be ''warm clusters.'' They contain enough internal energy to undergo a number of first-order processes, in particular that of evaporation. Because of this evaporation and its attendant cooling, the properties of such clusters are time-dependent. The states of matter which can be arrived at via an evaporative vector on a typical laboratory time-scale are discussed. Topics include the (1) temperatures, (2) metastability, (3) phase transitions, (4) kinetic energies of fragmentation, and (5) the expression of magical properties, all for evaporating homogeneous clusters

Do the VOCs that evaporate from a heavily polluted river threaten the health of riparian residents?

International Nuclear Information System (INIS)

Juang, Der-Fong; Lee, Chao-Hsien; Chen, Wei-Chin; Yuan, Chung-Shin

2010-01-01

To understand the potential threat of volatile organic compounds (VOCs) to the health of residents living close to a heavily polluted river, this study investigated the species and the concentration of VOCs evaporating from a river and surveyed the health condition of the nearby residents. Air samples were taken seasonally at the upstream, midstream, and downstream water surfaces of the river, and at different locations at certain distances from the river. These samples were analyzed qualitatively and quantitatively through gas chromatography and electron capture detector (GC/ECD) for chlorinated organic compounds, and through gas chromatography and flame ionization detector (GC/FID) for ordinary hydrocarbons. The health data obtained from valid health questionnaires of 908 residents were analyzed through Statistical Package for Social Science (SPSS) software. Twenty-six species of VOCs were identified in the environment adjacent the river, many of which are carcinogenic or believed to be carcinogenic to humans. However, results of this study shows that the VOCs evaporating from the polluted river have not been definitively identified as a major factor of cancer in the residents. However, the risk of suffering from certain chronic diseases may increase in residents living less than 225 m away from the river due to the high levels of evaporated VOCs. Residents living less than 225 m away from the river and with nearby specific industries are 3.130 times more at risk of suffering from chronic diseases than those with no nearby specific industries.

Measurements of the evaporation rate upon evaporation of thin layer at different heating modes

OpenAIRE

Gatapova E.Ya.; Korbanova E.G.

2017-01-01

Technique for measurements of the evaporation rate of a heated liquid layer is presented. The local minimum is observed which is associated with the point of equilibrium of the liquid–gas interface. It is shown when no heat is applied to the heating element temperature in gas phase is larger than in liquid, and evaporation occurs with the rate of 0.014–0.018 μl/s. Then evaporation rate is decreasing with increasing the heater temperature until the equilibrium point is reached at the liquid–ga...

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

Energy Technology Data Exchange (ETDEWEB)

Sujit Banerjee

2005-10-31

Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 µm are principally responsible. Georgia-Pacific is considering green

Topical application of polycyclic hydrocarbons to differentiated respiratory epithelium in long-term organ cultures

International Nuclear Information System (INIS)

Mossman, B.T.; Craighead, J.E.

1974-01-01

We undertook studies to assess the carcinogenic properties of selected hydrocarbons using the differentiated respiratory mucosa of the hamster trachea maintained in organ culture. Borosilicate glass fibers (diameter 3 x 10 -2 mm) were flushed with solutions of radio-labeled hydrocarbons in acetone and applied (after evaporation of the acetone) to the epithelial surface of the organ culture. This permitted us to vary the concentration of the carcinogen and allowed a systematic evaluation of epithelial changes at a defined site over a range of time periods. Presumably, the connective tissue elements subjacent to the mucosa were not exposed to the carcinogen. Cultures are maintained in a viable, differentiated state for two or more months as confirmed by histologic study and radioautography. Epithelial cells exhibit cytologic alterations and changes in 3 H-thymidine uptake at sites of fiber application after brief periods of exposure. Proliferation of the affected mucosa and loss of orientation of epithelial cells is noted. Possible neoplastic transformation of affected cells is currently being tested by implantation of cultures subcutaneously into syngeneic animals

Distribution of hydrocarbon-utilizing microorganisms and hydrocarbon biodegradation potentials in Alaskan continental shelf areas

International Nuclear Information System (INIS)

Roubal, G.; Atlas, R.M.

1978-01-01

Hydrocarbon-utilizing microogranisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of 14 C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using 14 C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene >> pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population

Polycyclic Aromatic Hydrocarbons

Science.gov (United States)

Salama, Farid

2010-01-01

Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

Occurrence and sources of aliphatic hydrocarbons in surface soils from Riyadh city, Saudi Arabia

Directory of Open Access Journals (Sweden)

Ahmed I. Rushdi

2013-01-01

Full Text Available Soil particles contain a variety of anthropogenic and natural organic components derived from many sources such as industrial and traffic fossil fuel emissions and terrestrial biota. The organic contents of soil and sand from the Arabian region have not fully characterized. Thus, samples of fine soil particles (sieved to <125 μM were collected from the Riyadh area in November 2006 (late summer and February 2007 (late winter. The samples were extracted with a mixture of dichloromethane/hexane and analyzed by gas chromatography–mass spectroscopy (GCMS in order to characterize the chemical composition and sources of aliphatic hydrocarbons. The results showed that both anthropogenic and natural biogenic inputs were the major sources of the aliphatic hydrocarbons in these extracts. Vehicular emission products and discarded plastics were the major anthropogenic sources in the fine particles of the soils and ranged from 64% to 96% in November 2006 and from 70% to 92% in February 2007. Their tracers were n-alkanes, hopanes, sterane, plasticizers and UCM. Vegetation was also a major natural source of hydrocarbon compounds in samples ranging from ∼0% to18% in November 2006 and from 1% to 13% in February 2007 and included n-alkanes and triterpenoids.

Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo droplet

NARCIS (Netherlands)

Tan, H.; Diddens, C.; Lv, P.; Kuerten, J.G.M.; Zhang, X.; Lohse, D.

2016-01-01

Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even

Evaporation-triggered microdroplet nucleation and the four life phases of an evaporating Ouzo drop

NARCIS (Netherlands)

Tan, Huanshu; Diddens, Christian; Lv, Pengyu; Kuerten, J.G.M.; Zhang, Xuehua; Lohse, Detlef

2016-01-01

Evaporating liquid droplets are omnipresent in nature and technology, such as in inkjet printing, coating, deposition of materials, medical diagnostics, agriculture, the food industry, cosmetics, or spills of liquids. Whereas the evaporation of pure liquids, liquids with dispersed particles, or even

Performance optimization of solar driven small-cooled absorption–diffusion chiller working with light hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Sayadi, Zouhour [U.R. Thermique et Thermodynamique des Procédés Industriels, Ecole Nationale d’Ingénieurs de Monastir (ENIM), Av. Ibn Jazzar, 5060 Monastir (Tunisia); Ben Thameur, Nizar, E-mail: nizarbenthameur@yahoo.fr [U.R. Thermique et Thermodynamique des Procédés Industriels, Ecole Nationale d’Ingénieurs de Monastir (ENIM), Av. Ibn Jazzar, 5060 Monastir (Tunisia); Bourouis, Mahmoud [Mechanical Engineering Department, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Bellagi, Ahmed [U.R. Thermique et Thermodynamique des Procédés Industriels, Ecole Nationale d’Ingénieurs de Monastir (ENIM), Av. Ibn Jazzar, 5060 Monastir (Tunisia)

2013-10-15

Highlights: • 1 kW{sub cooling} diffusion/absorption machine with light hydrocarbons as working fluids. • Hysys optimization to choose the optimal mixture for a better machine performance. • Cooling loads for a small bed-room (16 m{sup 2}) have been estimated into TRNSYS. • Economic assessment to choose the best combination of solar equipments. • Energy savings, CO{sub 2} avoided and equivalent gasoil and Diesel saved energy. - Abstract: We present in this paper a HYSYS (Aspen One) model and simulation results for 1 kW capacity water-cooled absorption/diffusion machine using different binary mixtures of light hydrocarbons as working fluids (C{sub 3}/n-C{sub 6}, C{sub 3}/c-C{sub 6}, C{sub 3}/c-C{sub 5}, propylene/c-C{sub 5}, propylene/i-C{sub 4}, propylene/i-C{sub 5}) in combination with helium as inert gas. The driving heat is supposed to be provided by an evacuated solar collector field. TRNSYS is used to address the solar aspects of the simulations. For the optimal chiller the driving heat temperature was found to be 121 °C for an evaporator exit temperature of 0 °C. The cooling water flow rate circulating between chiller and cooling tower is 140 l/h. Bubble pump and generator are heated by pressurized water from an insulated tank (70 l/m{sup 2}) maintained at a maximum temperature of 126 °C – with make-up heat when needed – and storing solar heat at an estimated 4.2 kW power. The solar energy cover only 40% for the energy supplied to drive the chiller. It’s found that the necessary collector surface area is about 6 m{sup 2} with annually total costs of 1.60 €/kW h with 20 years lifetime period for the installation. The avoided CO{sub 2} emissions are estimated at 1396 kg. The equivalent saved energy is 521 l of diesel or 604 l of gasoline.

Performance optimization of solar driven small-cooled absorption–diffusion chiller working with light hydrocarbons

International Nuclear Information System (INIS)

Sayadi, Zouhour; Ben Thameur, Nizar; Bourouis, Mahmoud; Bellagi, Ahmed

2013-01-01

Highlights: • 1 kW cooling diffusion/absorption machine with light hydrocarbons as working fluids. • Hysys optimization to choose the optimal mixture for a better machine performance. • Cooling loads for a small bed-room (16 m 2 ) have been estimated into TRNSYS. • Economic assessment to choose the best combination of solar equipments. • Energy savings, CO 2 avoided and equivalent gasoil and Diesel saved energy. - Abstract: We present in this paper a HYSYS (Aspen One) model and simulation results for 1 kW capacity water-cooled absorption/diffusion machine using different binary mixtures of light hydrocarbons as working fluids (C 3 /n-C 6 , C 3 /c-C 6 , C 3 /c-C 5 , propylene/c-C 5 , propylene/i-C 4 , propylene/i-C 5 ) in combination with helium as inert gas. The driving heat is supposed to be provided by an evacuated solar collector field. TRNSYS is used to address the solar aspects of the simulations. For the optimal chiller the driving heat temperature was found to be 121 °C for an evaporator exit temperature of 0 °C. The cooling water flow rate circulating between chiller and cooling tower is 140 l/h. Bubble pump and generator are heated by pressurized water from an insulated tank (70 l/m 2 ) maintained at a maximum temperature of 126 °C – with make-up heat when needed – and storing solar heat at an estimated 4.2 kW power. The solar energy cover only 40% for the energy supplied to drive the chiller. It’s found that the necessary collector surface area is about 6 m 2 with annually total costs of 1.60 €/kW h with 20 years lifetime period for the installation. The avoided CO 2 emissions are estimated at 1396 kg. The equivalent saved energy is 521 l of diesel or 604 l of gasoline

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.

Field emission from a new type of electron source

International Nuclear Information System (INIS)

Mousa, M.S.

1987-01-01

A new type of field emission electron source has been developed. In this paper, the construction, characteristics and behaviour of tungsten micropoint emitters coated with a sub-micron layer of hydrocarbon using a TEM with poor ( ∼ 1 0 -3 torr) vacuum conditions are described. The hydrocarbon coating has been verified using the X-Ray energy dispersive analysis technique of a SEM. The technical capabilities and potential of the new type of electron source are compared with those of other comparable composite micropoint field emitters and other types of electron sources currently in use. The emission properties presented here include I-V characteristics, emission images and electron energy spectra of this type of composite micropoint emitters. The effect on the behaviour and characteristics of baking the coated emitters at temperatures ranging between 140 0 C and 350 0 C is also studied. The behaviour of the emitter has been interpreted in terms of a field-induced hot-electron emission mechanism associated with metal-insulator-vacuum (M-I-V) regime

Spatio-temporal trends in monthly pan evaporation in Aguascalientes, Mexico

Science.gov (United States)

Ruiz-Alvarez, Osias; Singh, Vijay P.; Medina, Juan Enciso; Munster, Clyde; Kaiser, Ronald; Ontiveros-Capurata, Ronald Ernesto; Diaz-Garcia, Luis Antonio; dos Santos, Carlos Antonio Costa

2018-05-01

Emission of greenhouse gases is being alleged to be causing climate change in different regions of the world. The objective of this study was to analyze the spatio-temporal trends of monthly evaporation at 52 weather stations in the state of Aguascalientes (Mexico) which have hydrometeorological records of long periods. The autocorrelation was eliminated with an auto-regressive model, and the trend was determined using the Spearman (S) and Kendall (K) tests. The statistical significance of the trend was determined with the Spearman correlation coefficient (r s) and the Z statistic (the test statistic of the normal distribution) both indicated that that there were statistically significant trends in 107 time series, of these 88 series had negative trends and 19 series had positive trends. Negative trends were present in all months of the year, while positive trends occurred from February to May and from October to December only. The reduction of evaporation from - 4.10 to - 20.50 mm/month/year from June to September showed a hopeful future scenario for rainfed agriculture. Irrigated agriculture during dry months could have a reduction of irrigation requirements as a consequence of the reduction in reference and crop evapotranspiration. The evaporation increase during dry months could increase irrigation requirements and pumping, mainly in March, April, and November when there are trends with increases of about 26.90, 24.60, and 23.90 mm/month/year, respectively. The spatial variability of evaporation trend means that other effects of climate change could vary in different parts of the state. Results of this study will be useful for farmers and institutions in charge of the administration of water resources for developing adaptation and mitigation strategies to climate change.

242-A evaporator hazards assessment

International Nuclear Information System (INIS)

Johnson, T.L.

1998-01-01

This document establishes the technical basis in support of Emergency Planning activities for the 242-A Evaporator, on the Hanford Site. Through this document the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated. The evaporator sues a conventional, forced-circulation, vacuum evaporation system to concentrate radioactive waste solutions. This concentration results in the reduction in waste volume and reduces the number of double-shelled tanks required to store the waste

Drop evaporation and triple line dynamics

Science.gov (United States)

Sobac, Benjamin; Brutin, David; Gavillet, Jerome; Université de Provence Team; Cea Liten Team

2011-03-01

Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop deposited on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (PTFE, SiOx, SiOc and CF), the influence of the dynamic of the triple line on the evaporation process. The experiment consists in analyzing simultaneously the motion of the triple line, the kinetics of evaporation, the internal thermal motion and the heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamics of the evaporative heat flux appears clearly different depending of the motion of the triple line

Microbial communities involved in methane production from hydrocarbons in oil sands tailings.

Science.gov (United States)

Siddique, Tariq; Penner, Tara; Klassen, Jonathan; Nesbø, Camilla; Foght, Julia M

2012-09-04

Microbial metabolism of residual hydrocarbons, primarily short-chain n-alkanes and certain monoaromatic hydrocarbons, in oil sands tailings ponds produces large volumes of CH(4) in situ. We characterized the microbial communities involved in methanogenic biodegradation of whole naphtha (a bitumen extraction solvent) and its short-chain n-alkane (C(6)-C(10)) and BTEX (benzene, toluene, ethylbenzene, and xylenes) components using primary enrichment cultures derived from oil sands tailings. Clone libraries of bacterial 16S rRNA genes amplified from these enrichments showed increased proportions of two orders of Bacteria: Clostridiales and Syntrophobacterales, with Desulfotomaculum and Syntrophus/Smithella as the closest named relatives, respectively. In parallel archaeal clone libraries, sequences affiliated with cultivated acetoclastic methanogens (Methanosaetaceae) were enriched in cultures amended with n-alkanes, whereas hydrogenotrophic methanogens (Methanomicrobiales) were enriched with BTEX. Naphtha-amended cultures harbored a blend of these two archaeal communities. The results imply syntrophic oxidation of hydrocarbons in oil sands tailings, with the activities of different carbon flow pathways to CH(4) being influenced by the primary hydrocarbon substrate. These results have implications for predicting greenhouse gas emissions from oil sands tailings repositories.

Trends in evaporation of a large subtropical lake

Science.gov (United States)

Hu, Cheng; Wang, Yongwei; Wang, Wei; Liu, Shoudong; Piao, Meihua; Xiao, Wei; Lee, Xuhui

2017-07-01

How rising temperature and changing solar radiation affect evaporation of natural water bodies remains poor understood. In this study, evaporation from Lake Taihu, a large (area 2400 km2) freshwater lake in the Yangtze River Delta, China, was simulated by the CLM4-LISSS offline lake model and estimated with pan evaporation data. Both methods were calibrated against lake evaporation measured directly with eddy covariance in 2012. Results show a significant increasing trend of annual lake evaporation from 1979 to 2013, at a rate of 29.6 mm decade-1 according to the lake model and 25.4 mm decade-1 according to the pan method. The mean annual evaporation during this period shows good agreement between these two methods (977 mm according to the model and 1007 mm according to the pan method). A stepwise linear regression reveals that downward shortwave radiation was the most significant contributor to the modeled evaporation trend, while air temperature was the most significant contributor to the pan evaporation trend. Wind speed had little impact on the modeled lake evaporation but had a negative contribution to the pan evaporation trend offsetting some of the temperature effect. Reference evaporation was not a good proxy for the lake evaporation because it was on average 20.6 % too high and its increasing trend was too large (56.5 mm decade-1).

New models for droplet heating and evaporation

KAUST Repository

Sazhin, Sergei S.

2013-02-01

A brief summary of new models for droplet heating and evaporation, developed mainly at the Sir Harry Ricardo Laboratory of the University of Brighton during 2011-2012, is presented. These are hydrodynamic models for mono-component droplet heating and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono-component droplet heating and evaporation, and a model for mono-component droplet evaporation, based on molecular dynamics simulation. The results, predicted by the new models are compared with experimental data and the prehctions of the previously developed models where possible. © 2013 Asian Network for Scientific Information.

Evaporation, Boiling and Bubbles

Science.gov (United States)

Goodwin, Alan

2012-01-01

Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

Factors affecting hydrocarbon removal by air stripping

International Nuclear Information System (INIS)

McFarland, W.E.

1992-01-01

This paper includes an overview of the theory of air stripping design considerations and the factors affecting stripper performance. Effects of temperature, contaminant characteristics, stripping tower geometry and air/water ratios on removal performance are discussed. The discussion includes treatment of groundwater contaminated with petroleum hydrocarbons and chlorinated solvents such as TCE and PCE. Control of VOC emissions from air strippers has become a major concern in recent years, due to more stringent restrictions on air quality in many areas. This paper includes an overview of available technology to control air emissions (including activated carbon adsorption, catalytic oxidation and steam stripping) and the effects of air emission control on overall efficiency of the treatment process. The paper includes an overview of the relative performance of various packing materials for air strippers and explains the relative advantages and disadvantages of comparative packing materials. Field conditions affecting selection of packing materials are also discussed. Practical guidelines for the design of air stripping systems are presented, as well as actual case studies of full-scale air stripping projects

Treatment of liquid radioactive waste: Evaporation

International Nuclear Information System (INIS)

Pfeiffer, R.

1982-01-01

About 10.000 m 3 of low active liquid waste (LLW) arise in the Nuclear Research Center Karlsruhe. Chemical contents of this liquid waste are generally not declared. Resulting from experiments carried out in the Center during the early sixties, the evaporator facility was built in 1968 for decontamination of LLW. The evaporators use vapor compression and concentrate recirculation in the evaporator sump by pumps. Since 1971 the medium active liquid waste (MLW) from the Karlsruhe Reprocessing Plant (WAK) was decontaminated in this evaporator facility, too. By this time the amount of low liquid waste (LLW) had been decontaminated without mentionable interruptions. Afterwards a lot of interruptions of operations occurred, mainly due to leakages of pumps, valves and pipes. There was also a very high radiation level for the operating personnel. As a consequence of this experience a new evaporator facility for decontamination of medium active liquid waste was built in 1974. This facility started operation in 1976. The evaporator has natural circulation and is heated by steam through a heat exchanger. (orig./RW)

Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

International Nuclear Information System (INIS)

Westbrook, C.K.

2000-01-01

Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another

The evaporation of crude oil and petroleum products

International Nuclear Information System (INIS)

Fingas, M. F.

1996-01-01

The physics of oil and petroleum evaporation was studied by means of an experimental apparatus. The evaporation was determined by weight loss and recorded on a computer. Examination of the data showed that most oil and petroleum products (those with seven to ten components) evaporate at a logarithmic rate with respect to time, while other petroleum products (those with fewer chemical components) evaporate at a rate which is square root with respect to time. Evaporation of oil and petroleum was not strictly boundary-layer regulated because the typical oil evaporation rate rates do not exceed that of molecular diffusion and thus turbulent diffusion does not increase the evaporation rates. Overall, boundary layer regulation can be ignored in the prediction of oil and petroleum evaporation. The simple equation relating only the logarithm of time (or the square root of time in the case of narrow-cut products) and temperature are sufficient to accurately describe oil evaporation. refs., figs

Water evaporation: a transition path sampling study.

Science.gov (United States)

Varilly, Patrick; Chandler, David

2013-02-07

We use transition path sampling to study evaporation in the SPC/E model of liquid water. On the basis of thousands of evaporation trajectories, we characterize the members of the transition state ensemble (TSE), which exhibit a liquid-vapor interface with predominantly negative mean curvature at the site of evaporation. We also find that after evaporation is complete, the distributions of translational and angular momenta of the evaporated water are Maxwellian with a temperature equal to that of the liquid. To characterize the evaporation trajectories in their entirety, we find that it suffices to project them onto just two coordinates: the distance of the evaporating molecule to the instantaneous liquid-vapor interface and the velocity of the water along the average interface normal. In this projected space, we find that the TSE is well-captured by a simple model of ballistic escape from a deep potential well, with no additional barrier to evaporation beyond the cohesive strength of the liquid. Equivalently, they are consistent with a near-unity probability for a water molecule impinging upon a liquid droplet to condense. These results agree with previous simulations and with some, but not all, recent experiments.

Petroleum hydrocarbons

International Nuclear Information System (INIS)

Farrington, J.W.; Teal, J.M.; Parker, P.L.

1976-01-01

Methods for analysis of petroleum hydrocarbons in marine samples are presented. Types of hydrocarbons present and their origins are discussed. Principles and methods of analysis are outlined. Infrared spectrometry, uv spectrometry, gas chromatography, mass spectroscopy, and carbon 14 measurements are described

Modeling Evaporation and Particle Assembly in Colloidal Droplets.

Science.gov (United States)

Zhao, Mingfei; Yong, Xin

2017-06-13

Evaporation-induced assembly of nanoparticles in a drying droplet is of great importance in many engineering applications, including printing, coating, and thin film processing. The investigation of particle dynamics in evaporating droplets can provide fundamental hydrodynamic insight for revealing the processing-structure relationship in the particle self-organization induced by solvent evaporation. We develop a free-energy-based multiphase lattice Boltzmann method coupled with Brownian dynamics to simulate evaporating colloidal droplets on solid substrates with specified wetting properties. The influence of interface-bound nanoparticles on the surface tension and evaporation of a flat liquid-vapor interface is first quantified. The results indicate that the particles at the interface reduce surface tension and enhance evaporation flux. For evaporating particle-covered droplets on substrates with different wetting properties, we characterize the increase of evaporate rate via measuring droplet volume. We find that droplet evaporation is determined by the number density and circumferential distribution of interfacial particles. We further correlate particle dynamics and assembly to the evaporation-induced convection in the bulk and on the surface of droplet. Finally, we observe distinct final deposits from evaporating colloidal droplets with bulk-dispersed and interface-bound particles. In addition, the deposit pattern is also influenced by the equilibrium contact angle of droplet.

Residue pattern of polycyclic aromatic hydrocarbons during green tea manufacturing and their transfer rates during tea brewing.

Science.gov (United States)

Gao, Guanwei; Chen, Hongping; Liu, Pingxiang; Hao, Zhenxia; Ma, Guicen; Chai, Yunfeng; Wang, Chen; Lu, Chengyin

2017-06-01

Residues of polycyclic aromatic hydrocarbons (PAHs) in green tea and tea infusion were determined using gas chromatography-tandem mass spectrometry to study their dissipation pattern during green tea processing and infusion. Concentration and evaporation of PAHs during tea processing were the key factors affecting PAH residue content in product intermediates and in green tea. PAH residues in tea leaves increased by 2.4-3.1 times during the manufacture of green tea using the electric heating model. After correction to dry weight, PAH residue concentrations decreased by 33.5-48.4% during green tea processing because of PAH evaporation. Moreover, spreading and drying reduced PAH concentrations. The transfer rates of PAH residues from green tea to infusion varied from 4.6% to 7.2%, and PAH leaching was higher in the first infusion than in the second infusion. These results are useful for assessing exposure to PAHs from green tea and in formulating controls for the maximum residue level of PAHs in green tea.

Evaporation From Soil Containers With Irregular Shapes

Science.gov (United States)

Assouline, Shmuel; Narkis, Kfir

2017-11-01

Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

Evaporative lithographic patterning of binary colloidal films.

Science.gov (United States)

Harris, Daniel J; Conrad, Jacinta C; Lewis, Jennifer A

2009-12-28

Evaporative lithography offers a promising new route for patterning a broad array of soft materials. In this approach, a mask is placed above a drying film to create regions of free and hindered evaporation, which drive fluid convection and entrained particles to regions of highest evaporative flux. We show that binary colloidal films exhibit remarkable pattern formation when subjected to a periodic evaporative landscape during drying.

Evaporative cooling in polymer electrolyte fuel cell

Energy Technology Data Exchange (ETDEWEB)

Shimotori, S; Sonai, A [Toshiba Corp. Tokyo (Japan)

1996-06-05

The concept of the evaporative cooling for the internally humidified PEFC was confirmed by the experiment. The evaporative cooling rates at the anode and the cathode were mastered under the various temperatures and air utilizations. At a high temperature the proportion of the evaporative cooling rate to the heat generation rate got higher, the possibility of the evaporative cooling was demonstrated. 2 refs., 7 figs., 1 tab.

Intrinsic Evaporative Cooling by Hygroscopic Earth Materials

Directory of Open Access Journals (Sweden)

Alexandra R. Rempel

2016-08-01

Full Text Available The phase change of water from liquid to vapor is one of the most energy-intensive physical processes in nature, giving it immense potential for cooling. Diverse evaporative cooling strategies have resulted worldwide, including roof ponds and sprinklers, courtyard fountains, wind catchers with qanats, irrigated green roofs, and fan-assisted evaporative coolers. These methods all require water in bulk liquid form. The evaporation of moisture that has been sorbed from the atmosphere by hygroscopic materials is equally energy-intensive, however, yet has not been examined for its cooling potential. In arid and semi-arid climates, hygroscopic earth buildings occur widely and are known to maintain comfortable indoor temperatures, but evaporation of moisture from their walls and roofs has been regarded as unimportant since water scarcity limits irrigation and rainfall; instead, their cool interiors are attributed to well-established mass effects in delaying the transmission of sensible gains. Here, we investigate the cooling accomplished by daily cycles of moisture sorption and evaporation which, requiring only ambient humidity, we designate as “intrinsic” evaporative cooling. Connecting recent soil science to heat and moisture transport studies in building materials, we use soils, adobe, cob, unfired earth bricks, rammed earth, and limestone to reveal the effects of numerous parameters (temperature and relative humidity, material orientation, thickness, moisture retention properties, vapor diffusion resistance, and liquid transport properties on the magnitude of intrinsic evaporative cooling and the stabilization of indoor relative humidity. We further synthesize these effects into concrete design guidance. Together, these results show that earth buildings in diverse climates have significant potential to cool themselves evaporatively through sorption of moisture from humid night air and evaporation during the following day’s heat. This finding

Pollutant emissions of commercial and industrial wood furnaces; determination of emissions and emission reducing techniques

International Nuclear Information System (INIS)

Baumbach, G.; Angerer, M.

1993-01-01

Approximately 382.000 t of wood waste from production processes are fired in Baden-Wuerttemberg per year in 4345 furnaces with capacities of less than 1 MW (field of application of the ''1 BImSchV''). This corresponds to an energy consumption of 5600 TJ. The firings with a totally installed capacity of 594 MW are operated mainly by joiners, carpenters, in sawmills and furniture factories. Certainly there are typical differences between the diverse branches concerning the characteristics of the firings such as capacity, kind of firing, of fuel supply and heat generation. Because of lacking established emission factors, at present time the emissions of these furnaces cannot be calculated. Therefore field measurements are carried out at a representative selection of the registered installations. The emissions are measured in consideration of the usual ways of operation and the commonly used fuels. Supplementarily the compound of the emitted hydrocarbons and their dependence on completeness of the combustion as well as the compound and the grain size distribution of the particle emissions are investigated. (orig.) [de

Towards a rational definition of potential evaporation

Directory of Open Access Journals (Sweden)

J.-P. Lhommel

1997-01-01

Full Text Available The concept of potential evaporation is defined on the basis of the following criteria: (i it must establish an upper limit to the evaporation process in a given environment (the term 'environment' including meteorological and surface conditions, and (ii this upper limit must be readily calculated from measured input data. It is shown that this upper limit is perfectly defined and is given by the Penman equation, applied with the corresponding meteorological data (incoming radiation and air characteristics measured at a reference height and the appropriate surface characteristics (albedo, roughness length, soil heat flux. Since each surface has its own potential evaporation, a function of its own surface characteristics, it is useful to define a reference potential evaporation as a short green grass completely shading the ground. Although the potential evaporation from a given surface is readily calculated from the Penman equation, its physical significance or interpretation is not so straightforward, because it represents only an idealized situation, not a real one. Potential evaporation is the evaporation from this surface, when saturated and extensive enough to obviate any effect of local advection, under the same meteorological conditions. Due to the feedback effects of evaporation on air characteristics, it does not represent the 'real' evaporation (i.e. the evaporation which could be physically observed in the real world from such an extensive saturated surface in these given meteorological conditions (if this saturated surface were substituted for an unsaturated one previously existing. From a rigorous standpoint, this calculated potential evaporation is not physically observable. Nevertheless, an approximate representation can be given by the evaporation from a limited saturated area, the dimension of which depends on the height of measurement of the air characteristics used as input in the Penman equation. If they are taken at a height

UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers

Science.gov (United States)

Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.; Gillette, J. S.; Clemett, S. J.; Zare, R. N.

1999-01-01

Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.

Evaporation of decamethylcyclopentasiloxane (D5) from selected cosmetic products: Implications for consumer exposure modeling.

Science.gov (United States)

Dudzina, Tatsiana; Garcia Hidalgo, Elena; von Goetz, Natalie; Bogdal, Christian; Hungerbuehler, Konrad

2015-11-01

Consumer exposure to leave-on cosmetics and personal care products (C&PCPs) ingredients of low or moderate volatility is often assumed to occur primarily via dermal absorption. In reality they may volatilize from skin and represent a significant source for inhalation exposure. Often, evaporation rates of pure substances from inert surfaces are used as a surrogate for evaporation from more complex product matrices. Also the influence of partitioning to skin is neglected and the resulting inaccuracies are not known. In this paper we describe a novel approach for measuring chemical evaporation rates from C&PCPs under realistic consumer exposure conditions. Series of experiments were carried out in a custom-made ventilated chamber fitted with a vapor trap to study the disposition of a volatile cosmetic ingredient, decamethylcyclopentasiloxane (D5), after its topical application on either aluminum foil or porcine skin in vitro. Single doses were applied neat and in commercial deodorant and face cream formulations at normal room (23°C) and skin temperature (32°C). The condition-specific evaporation rates were determined as the chemical mass loss per unit surface area at different time intervals over 1-1.25h post-dose. Product weight loss was monitored gravimetrically and the residual D5 concentrations were analyzed with GC/FID. The release of D5 from exposed surfaces of aluminum occurred very fast with mean rates of 0.029 mg cm(-2)min(-1) and 0.060 mg cm(-2)min(-1) at 23°C and 32°C, respectively. Statistical analysis of experimental data confirmed a significant effect of cosmetic formulations on the evaporation of D5 with the largest effect (2-fold decrease of the evaporation rate) observed for the neat face cream pair at 32°C. The developed approach explicitly considers the initial penetration and evaporation of a substance from the Stratum Corneum and has the potential for application in dermal exposure modeling, product emission tests and the formulation of C

Modelling refrigerant distribution in microchannel evaporators

DEFF Research Database (Denmark)

Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

2009-01-01

of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...... out of the evaporator is kept constant. It is shown that the cooling capacity of the evaporator is reduced significantly, both in the case of unevenly distributed inlet quality and for the case of non-uniform airflow on the outside of the channels.......The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...

Is evaporative colling important for shallow clouds?

Science.gov (United States)

Gentine, P.; Park, S. B.; Davini, P.; D'Andrea, F.

2017-12-01

We here investigate and test using large-eddy simulations the hypothesis that evaporative cooling might not be crucial for shallow clouds. Results from various Shallow convection and stratocumulus LES experiments show that the influence of evaporative cooling is secondary compared to turbulent mixing, which dominates the buoyancy reversal. In shallow cumulus subising shells are not due to evaporative cooling but rather reflect a vortical structure, with a postive buoyancy anomaly in the core due to condensation. Disabling evaporative cooling has negligible impact on this vortical structure and on buoyancy reversal. Similarly in non-precipitating stratocumuli evaporative cooling is negeligible copmared to other factors, especially turbulent mixing and pressure effects. These results emphasize that it may not be critical to icnlude evaporative cooling in parameterizations of shallow clouds and that it does not alter entrainment.

Integration of direct carbon and hydrogen fuel cells for highly efficient power generation from hydrocarbon fuels

Energy Technology Data Exchange (ETDEWEB)

Muradov, Nazim; Choi, Pyoungho; Smith, Franklyn; Bokerman, Gary [Florida Solar Energy Center, University of Central Florida, 1679 Clearlake Road, Cocoa, FL 32922-5703 (United States)

2010-02-15

In view of impending depletion of hydrocarbon fuel resources and their negative environmental impact, it is imperative to significantly increase the energy conversion efficiency of hydrocarbon-based power generation systems. The combination of a hydrocarbon decomposition reactor with a direct carbon and hydrogen fuel cells (FC) as a means for a significant increase in chemical-to-electrical energy conversion efficiency is discussed in this paper. The data on development and operation of a thermocatalytic hydrocarbon decomposition reactor and its coupling with a proton exchange membrane FC are presented. The analysis of the integrated power generating system including a hydrocarbon decomposition reactor, direct carbon and hydrogen FC using natural gas and propane as fuels is conducted. It was estimated that overall chemical-to-electrical energy conversion efficiency of the integrated system varied in the range of 49.4-82.5%, depending on the type of fuel and FC used, and CO{sub 2} emission per kW{sub el}h produced is less than half of that from conventional power generation sources. (author)

Crystallization of urea from an evaporative aqueous solution sessile droplet at sub-boiling temperatures and surfaces with different wettability

NARCIS (Netherlands)

Schmid, J.; Zarikos, I.; Terzis, A.; Roth, N.; Weigand, B.

The injection of urea-water-solution sprays in the exhaust pipe of modern diesel engines eliminates NOx emissions in a very great extent. However, as water evaporates from the solution, urea is crystallized and causes walldeposit formations hindering the performance of selective-catalytic-reaction.

Dual manifold heat pipe evaporator

Science.gov (United States)

Adkins, D.R.; Rawlinson, K.S.

1994-01-04

An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

Assessing the impacts of ethanol and isobutanol on gaseous and particulate emissions from flexible fuel vehicles.

Science.gov (United States)

Karavalakis, Georgios; Short, Daniel; Russell, Robert L; Jung, Heejung; Johnson, Kent C; Asa-Awuku, Akua; Durbin, Thomas D

2014-12-02

This study investigated the effects of higher ethanol blends and an isobutanol blend on the criteria emissions, fuel economy, gaseous toxic pollutants, and particulate emissions from two flexible-fuel vehicles equipped with spark ignition engines, with one wall-guided direct injection and one port fuel injection configuration. Both vehicles were tested over triplicate Federal Test Procedure (FTP) and Unified Cycles (UC) using a chassis dynamometer. Emissions of nonmethane hydrocarbons (NMHC) and carbon monoxide (CO) showed some statistically significant reductions with higher alcohol fuels, while total hydrocarbons (THC) and nitrogen oxides (NOx) did not show strong fuel effects. Acetaldehyde emissions exhibited sharp increases with higher ethanol blends for both vehicles, whereas butyraldehyde emissions showed higher emissions for the butanol blend relative to the ethanol blends at a statistically significant level. Particulate matter (PM) mass, number, and soot mass emissions showed strong reductions with increasing alcohol content in gasoline. Particulate emissions were found to be clearly influenced by certain fuel parameters including oxygen content, hydrogen content, and aromatics content.

Evaporation from a sphagnum moss surface

Science.gov (United States)

D.S. Nichols; J.M. Brown

1980-01-01

Peat cores, 45 cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss surface was greater than that from a free-water surface. Evaporation from the moss increased...

Evaluation of the performance and response of the bacharach TLV sniffer and H-Nu photoionization gas analyzer to common hydrocarbon solvents.

Science.gov (United States)

Chelton, C F; Zakraysek, N; Lautner, G M; Confer, R G

1983-10-01

Two direct reading instruments, the H-Nu PI 101 photoionization analyzer and the J.W. Bacharach TLV Sniffer, were evaluated under laboratory conditions to determine their performance characteristics when challenged by vapors of common hydrocarbon solvent mixtures. Each instrument was evaluated against the manufacturer's recommended test solvent for rise time, fall time, noise, span drift, zero drift, position sensitivity, battery life, and recharge time. The precision, accuracy, and operating linear range were also determined for the test solvents and some petroleum solvent mixtures which are common refinery products. For these latter mixtures, correction factors are presented which allow for an improved estimate of ambient concentrations when monitoring with each of these instruments. All tests except operating humidity range were performed by challenging each instrument with a known concentration of hydrocarbon generated by evaporating calculated liquid volumes into a static chamber. Humidity tests were performed using a dynamic dilution apparatus generating a fixed concentration of hydrocarbon while relative humidity was varied. Concentrations in both systems were verified by gas injection into gas chromatograph. Each instrument performed well when challenged by manufacturers' recommended test solvents. Humidity was shown to influence each instrument's readings. Also, the instruments were shown to have application as monitors of airborne concentrations of common hydrocarbon solvent mixtures.

Converting high boiling hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Terrisse, H; DuFour, L

1929-02-12

A process is given for converting high boiling hydrocarbons into low boiling hydrocarbons, characterized in that the high boiling hydrocarbons are heated to 200 to 500/sup 0/C in the presence of ferrous chloride and of such gases as hydrogen, water gas, and the like gases under a pressure of from 5 to 40 kilograms per square centimeter. The desulfurization of the hydrocarbons occurs simultaneously.

Etherify field butanes

International Nuclear Information System (INIS)

Sarathy, P.R.; Suffridge, G.S.

1993-01-01

This paper reports on capital and operating cost considerations which can be reviewed, with technology alternatives and preferences, to develop investment analyses for large MTBE projects consisting of butane isomerization, isobutane dehydrogenation and isobutylene etherification. fuel oxygenates improve hydrocarbon burning efficiency of gasolines and reduce carbon monoxide emissions. They also help reduce atmospheric ozone resulting from gasoline evaporative emissions due to their lower volatility and atmospheric reactivity characteristics in comparison with hydrocarbon constituents of the refinery gasoline they replace. These polluted areas are also the country's population centers. Because of oxygenates' clean-burning properties, they are expected to play a significant role in U. S. gasoline blends. A significant role is also projected for the rest of the world, where clean burning high octane fuels will be needed

Estimation and characterization of polycyclic aromatic hydrocarbons from magnesium metallurgy facilities in China.

Science.gov (United States)

Nie, Zhiqiang; Yang, Yufei; Tang, Zhenwu; Liu, Feng; Wang, Qi; Huang, Qifei

2014-11-01

Field monitoring was conducted to develop a polycyclic aromatic hydrocarbon (PAH) emission inventory for the magnesium (Mg) metallurgy industry in China. PAH emissions in stack gas and fly/bottom ash samples from different smelting units of a typical Mg smelter were measured and compared. Large variations of concentrations, congener patterns, and emission factors of PAHs during the oxidation and reduction stages in the Mg smelter were observed. The measured average emission factor (166,487 μg/t Mg) was significantly higher than those of other industrial sources. Annual emission from Mg metallurgy in 2012 in China was estimated at 116 kg (514 g BaPeq) for PAHs. The results of this study suggest that PAH emission from Mg industries should be considered by local government agencies. These data may be helpful for understanding PAH levels produced by the Mg industry and in developing a PAH inventory.

THE GEOLOGICAL CONDITIONING OF HYDROCARBON EMISSIONS RESULTING FROM SOIL CONTAMINATION

Directory of Open Access Journals (Sweden)

Ewa J. Lipińska

2014-12-01

Full Text Available Synchronization economy of oil mining and mineral waters is associated with planning the functions of spa treatment. Environmental protection of the spa areas also applies to preserve their technical and cultural heritage. This article attempts to determine the places of natural and anthropogenic hydrocarbon pollution substances. Their presence in the soil affects the quality of the environment. As a result, maps are produced showing directions of research: (1 the natural background of biodiversity, and (2 potential anthropogenic pollution. They are assessed in the context of the health and human life, protection of the environment and the possibility of damage to the environment. Research is conducted in communes of the status of the spa – for special protection.

New models for droplet heating and evaporation

KAUST Repository

Sazhin, Sergei S.; Elwardani, Ahmed Elsaid; Gusev, Ivan G.; Xie, Jianfei; Shishkova, Irina N.; Cao, Bingyang; Snegirev, Alexander Yu.; Heikal, Morgan Raymond

2013-01-01

and evaporation, taking into account the effects of the moving boundary due to evaporation, hydrodynamic models of multi-component droplet heating and evaporation, taking and not taking into account the effects of the moving boundary, new kinetic models of mono

KEPLER PLANETS: A TALE OF EVAPORATION

International Nuclear Information System (INIS)

Owen, James E.; Wu, Yanqin

2013-01-01

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ⊕ . Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ⊕ and