Methane monitoring from space

Science.gov (United States)

Stephan, C.; Alpers, M.; Millet, B.; Ehret, G.; Flamant, P.

2017-11-01

Methane is one of the strongest anthropogenic greenhouse gases. It contributes by its radiative forcing significantly to the global warming. For a better understanding of climate changes, it is necessary to apply precise space-based measurement techniques in order to obtain a global view on the complex processes that control the methane concentration in the atmosphere. The MERLIN mission is a joint French-German cooperation, on a micro satellite mission for space-based measurement of spatial and temporal gradients of atmospheric methane columns on a global scale. MERLIN will be the first Integrated Path Differential Absorption LIDAR for greenhouse gas monitoring from space. In contrast to passive methane missions, the LIDAR instrument allows measurements at alllatitudes, all-seasons and during night.

Working group report: methane emissions from biomass burning

International Nuclear Information System (INIS)

Delmas, R.A.; Ahuja, D.

1993-01-01

Biomass burning is a significant source of atmospheric methane. Like most other sources of methane, it has both natural and anthropogenic causes, although anthropogenic causes now predominate. Most of the estimates of methane emissions from biomass burning in the past have relied on a uniform emission factor for all types of burning. This results in the share of trace gas emissions for different types of burning being the same as the amounts of biomass burned in those types. The Working Group endorsed the extension of an approach followed for Africa by Delmas et al. (1991) to use different emission factors for different types of biomass burning to estimate national emissions of methane. This is really critical as emission factors present important variations. While the focus of discussions of the Working Group was on methane emissions from biomass burning, the Group endorsed the IPCC-OECD methodology of estimating all greenhouse related trace gases from biomass burning. Neither the IPCC-OECD nor the methodology suggested here applies to estimation of trace gas emissions from the processing of biomass to upgraded fuels. They must be estimated separately. The Group also discussed technical options for controlling methane emissions from biomass. 12 refs

Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions

DEFF Research Database (Denmark)

Scheutz, Charlotte; Kjeldsen, Peter; Bogner, J.E.

2009-01-01

Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials...... to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed....

The indirect global warming potential and global temperature change potential due to methane oxidation

International Nuclear Information System (INIS)

Boucher, Olivier; Collins, Bill; Friedlingstein, Pierre; Shine, Keith P

2009-01-01

Methane is the second most important anthropogenic greenhouse gas in the atmosphere next to carbon dioxide. Its global warming potential (GWP) for a time horizon of 100 years is 25, which makes it an attractive target for climate mitigation policies. Although the methane GWP traditionally includes the methane indirect effects on the concentrations of ozone and stratospheric water vapour, it does not take into account the production of carbon dioxide from methane oxidation. We argue here that this CO 2 -induced effect should be included for fossil sources of methane, which results in slightly larger GWP values for all time horizons. If the global temperature change potential is used as an alternative climate metric, then the impact of the CO 2 -induced effect is proportionally much larger. We also discuss what the correction term should be for methane from anthropogenic biogenic sources.

Attributing Methane and Carbon Dioxide Emissions from Anthropogenic and Natural Sources Using AVIRIS-NG

Science.gov (United States)

Thorpe, A. K.; Frankenberg, C.; Thompson, D. R.; Duren, R. M.; Aubrey, A. D.; Bue, B. D.; Green, R. O.; Gerilowski, K.; Krings, T.; Borchardt, J.; Kort, E. A.; Sweeney, C.; Conley, S. A.; Roberts, D. A.; Dennison, P. E.; Ayasse, A.

2016-12-01

Imaging spectrometers like the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) can map large regions with the high spatial resolution necessary to resolve methane (CH4) and carbon dioxide (CO2) emissions. This capability is aided by real time detection and geolocation of gas plumes, permitting unambiguous identification of individual emission source locations and communication to ground teams for rapid follow up. We present results from AVIRIS-NG flight campaigns in the Four Corners region (Colorado and New Mexico) and the San Joaquin Valley (California). Over three hundred plumes were observed, reflecting emissions from anthropogenic and natural sources. Examples of plumes will be shown for a number of sources, including CH4 from well completions, gas processing plants, tanks, pipeline leaks, natural seeps, and CO2 from power plants. Despite these promising results, an imaging spectrometer built exclusively for quantitative mapping of gas plumes would have improved sensitivity compared to AVIRIS-NG. For example, an instrument providing a 1 nm spectral sampling (2,000-2,400 micron) would permit mapping CH4, CO2, H2O, CO, and N2O from more diffuse sources using both airborne and orbital platforms. The ability to identify emission sources offers the potential to constrain regional greenhouse gas budgets and improve partitioning between anthropogenic and natural emission sources. Because the CH4 lifetime is only about 9 years and CH4 has a Global Warming Potential 86 times that of CO2 for a 20 year time interval, mitigating these emissions is a particularly cost-effective approach to reduce overall atmospheric radiative forcing. Fig. 1. True color image subset with superimposed gas plumes showing concentrations in ppmm. Left: AVIRIS-NG observed CH4 plumes from natural gas processing plant extending over 500 m downwind of multiple emissions sources. Right: Multiple CO2 plumes observed from coal-fired power plant.

Methane emissions and climate compatibility of fossil fuels

International Nuclear Information System (INIS)

Meier, B.

1992-01-01

Methane contributes directly and indirectly to the additional greenhouse effect caused by human activities. The vast majority of the anthropogenic methane release occurs worldwide in non-fossil sources such as rice cultivation, livestock operations, sanitary landfills and combustion of bio-mass. Methane emissions also occur during production, distribution and utilisation of fossil fuels. Also when considering the methane release and CO 2 -emissions of processes upstream of combustion, the ranking of environmental compatibility of natural gas, fuel oil and cool remains unchanged. Of all fossil fuels, natural gas contributes the least to the greenhouse effect. (orig.) [de

Environmental impacts on the diversity of methane-cycling microbes and their resultant function

OpenAIRE

Emma eAronson; Emma eAronson; Steven eAllison; Steven eAllison; Brent R Helliker

2013-01-01

Methane is an important anthropogenic greenhouse gas that is produced and consumed in soils by microorganisms responding to micro-environmental conditions. Current estimates show that soil consumption accounts for 5-15% of methane removed from the atmosphere on an annual basis. Recent variability in atmospheric methane concentrations has called into question the reliability of estimates of methane consumption and call for novel approaches in order to predict future atmospheric methane trends....

Environmental impacts on the diversity of methane-cycling microbes and their resultant function

OpenAIRE

Aronson, Emma L; Allison, Steven D; Helliker, Brent R

2013-01-01

Methane is an important anthropogenic greenhouse gas that is produced and consumed in soils by microorganisms responding to micro-environmental conditions. Current estimates show that soil consumption accounts for 5?15% of methane removed from the atmosphere on an annual basis. Recent variability in atmospheric methane concentrations has called into question the reliability of estimates of methane consumption and calls for novel approaches in order to predict future atmospheric methane trends...

Upward revision of global fossil fuel methane emissions based on isotope database.

Science.gov (United States)

Schwietzke, Stefan; Sherwood, Owen A; Bruhwiler, Lori M P; Miller, John B; Etiope, Giuseppe; Dlugokencky, Edward J; Michel, Sylvia Englund; Arling, Victoria A; Vaughn, Bruce H; White, James W C; Tans, Pieter P

2016-10-06

Methane has the second-largest global radiative forcing impact of anthropogenic greenhouse gases after carbon dioxide, but our understanding of the global atmospheric methane budget is incomplete. The global fossil fuel industry (production and usage of natural gas, oil and coal) is thought to contribute 15 to 22 per cent of methane emissions to the total atmospheric methane budget. However, questions remain regarding methane emission trends as a result of fossil fuel industrial activity and the contribution to total methane emissions of sources from the fossil fuel industry and from natural geological seepage, which are often co-located. Here we re-evaluate the global methane budget and the contribution of the fossil fuel industry to methane emissions based on long-term global methane and methane carbon isotope records. We compile the largest isotopic methane source signature database so far, including fossil fuel, microbial and biomass-burning methane emission sources. We find that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are not increasing over time, but are 60 to 110 per cent greater than current estimates owing to large revisions in isotope source signatures. We show that this is consistent with the observed global latitudinal methane gradient. After accounting for natural geological methane seepage, we find that methane emissions from natural gas, oil and coal production and their usage are 20 to 60 per cent greater than inventories. Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 per cent to approximately 2 per cent over the past three decades.

Nonequilibrium clumped isotope signals in microbial methane

Science.gov (United States)

Wang, David T.; Gruen, Danielle S.; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C.; Holden, James F.; Hristov, Alexander N.; Pohlman, John W.; Morrill, Penny L.; Könneke, Martin; Delwiche, Kyle B.; Reeves, Eoghan P.; Sutcliffe, Chelsea N.; Ritter, Daniel J.; Seewald, Jeffrey S.; McIntosh, Jennifer C.; Hemond, Harold F.; Kubo, Michael D.; Cardace, Dawn; Hoehler, Tori M.; Ono, Shuhei

2015-01-01

Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

Chlorine isotope evidence for the anthropogenic origin of tris-(4-chlorophenyl)methane

International Nuclear Information System (INIS)

Holmstrand, Henry; Zencak, Zdenek; Mandalakis, Manolis; Andersson, Per; Gustafsson, Orjan

2010-01-01

Research highlights: → TCPMe is a bioaccumulating organochlorine found at significant levels in organisms at high trophic levels, e.g. birds and mammals. → Previous investigations have suggested TCPMe being co-released as a trace byproduct in pesticides such as DDT. → The results from compound-specific chlorine isotope analysis of TCPMe supports the hypothesis that the source of TCPMe is indeed the extensive historical use of DDT. - Abstract: Compound-specific Cl-isotope analysis was performed on the persistent and bioaccumulating compound tris-(4-chlorophenyl)methane (4,4',4''-TCPMe, referred to as TCPMe in this study) to elucidate whether its main source is natural or anthropogenic. Blubber from the Baltic grey seal (Halichoerus grypus) was extracted by continuous acetonitrile partitioning, and the TCPMe was isolated from the extract by preparative-capillary gas chromatography. Chlorine isotope analysis was subsequently performed by sealed-tube combustion in conjunction with thermal-ionization mass spectrometry (TIMS). The δ 37 Cl of TCPMe was -3.5 ± 0.5 per mille, similar to the previously reported δ 37 Cl of technical grade p,p'-DDT (referred to as DDT in this study). The data is not consistent with a putative marine natural source of TCPMe, as enzymatic (biotic) production is reported to give values of δ 37 Cl 37 Cl-TCPMe data thus supports the hypothesis that TCPMe is produced as a byproduct during DDT synthesis and is released to the environment through the same pathways as DDT. It is also consistent with tris-(4-chlorophenyl)methanol as the primary biotransformation product of TCPMe.

Methane fluxes from tropical coastal lagoons surrounded by mangroves, Yucatán, Mexico

Science.gov (United States)

Chuang, P.-C.; Young, M. B.; Dale, A. W.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

2017-05-01

Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m-2 d-1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event.

Science.gov (United States)

Petrenko, Vasilii V; Smith, Andrew M; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F; Severinghaus, Jeffrey P

2017-08-23

Methane (CH 4 ) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane ( 14 CH 4 ) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today's natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

Minimal geological methane emissions during the Younger Dryas-Preboreal abrupt warming event

Science.gov (United States)

Petrenko, Vasilii V.; Smith, Andrew M.; Schaefer, Hinrich; Riedel, Katja; Brook, Edward; Baggenstos, Daniel; Harth, Christina; Hua, Quan; Buizert, Christo; Schilt, Adrian; Fain, Xavier; Mitchell, Logan; Bauska, Thomas; Orsi, Anais; Weiss, Ray F.; Severinghaus, Jeffrey P.

2017-08-01

Methane (CH4) is a powerful greenhouse gas and plays a key part in global atmospheric chemistry. Natural geological emissions (fossil methane vented naturally from marine and terrestrial seeps and mud volcanoes) are thought to contribute around 52 teragrams of methane per year to the global methane source, about 10 per cent of the total, but both bottom-up methods (measuring emissions) and top-down approaches (measuring atmospheric mole fractions and isotopes) for constraining these geological emissions have been associated with large uncertainties. Here we use ice core measurements to quantify the absolute amount of radiocarbon-containing methane (14CH4) in the past atmosphere and show that geological methane emissions were no higher than 15.4 teragrams per year (95 per cent confidence), averaged over the abrupt warming event that occurred between the Younger Dryas and Preboreal intervals, approximately 11,600 years ago. Assuming that past geological methane emissions were no lower than today, our results indicate that current estimates of today’s natural geological methane emissions (about 52 teragrams per year) are too high and, by extension, that current estimates of anthropogenic fossil methane emissions are too low. Our results also improve on and confirm earlier findings that the rapid increase of about 50 per cent in mole fraction of atmospheric methane at the Younger Dryas-Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates, permafrost and methane trapped under ice) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas-Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.

Reducing methane emissions from ruminant animals

Energy Technology Data Exchange (ETDEWEB)

Mathison, G.W.; Okine, E.K.; McAllister, T.A.; Dong, Y.; Galbraith, J.; Dmytruk, O.I.N. [University of Alberta, Edmonton, AB (Canada). Dept. of Agriculture, Food and Nutrition Science

1998-09-01

In 1992 it was estimated that 30 x 10{sup 12}g more methane was emitted into the atmosphere than was removed, with animals being considered the largest single anthropogenic source. Ruminants produce 97% of the methane generated in enteric fermentation by animals. Estimates for methane emissions from animal wastes vary between 6 and 31% of that produced directly by the animal, with the most likely value being between 5 and 10% globally. Methane inhibitors can reduce methane emissions to zero in the short term but due to microbial adaptation the effects of these compounds are quickly neutralized and feed intake is often depressed. Methane emissions per unit of feed consumed from sheep and cattle fed hay diets appear to be quite similar but differences between other ruminants have been measured. The most practical way of influencing methane emissions per unit product is to increase productivity level since the proportion of feed energy required to just maintain the animal will be reduced, methane production falls with increased intake level, and the animal may go to market sooner. The most promising avenues for future research for reducing methanogenesis are the development of new products for reducing protozoal numbers in the rumen and the use of bacterocins or other compounds which specifically target methanogenic bacteria.

Intercalibration of selected anthropogenic radionuclides for the GEOTRACES Program

DEFF Research Database (Denmark)

Kenna, Timothy C.; Masqué, Pere; Mas, Jose Luis

2012-01-01

As part of the GEOTRACES Program, six laboratories participated in an intercalibration exercise on several anthropogenic radionuclides of interest. The effort was successful for 239,240Pu activity, 240Pu/239Pu isotope ratio, and 137Cs activity measured in filtered seawater samples from the Bermuda...... Atlantic Time Series station (BATS) and a site on the continental slope of the Northeastern U.S. A limited number of analyses were reported for 237Np, 241Am, 90Sr, and 238Pu in filtered seawater. Intercalibration of any of the isotopes of interest in filtered particulate matter was unsuccessful due...... to insufficient size of the samples distributed. Methods used were based on traditional radio-counting techniques and inductively coupled plasma mass spectrometry (ICP-MS). Although the majority of analyses were performed on samples ≥ 60 L, one lab demonstrated the ability to analyze several of the anthropogenic...

The Global Methane Budget 2000-2012

Science.gov (United States)

Saunois, Marielle; Bousquet, Philippe; Poulter, Benjamin; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander;

Anthropogenic Climate Change in Undergraduate Marine and Environmental Science Programs in the United States

Science.gov (United States)

Vlietstra, Lucy S.; Mrakovcich, Karina L.; Futch, Victoria C.; Stutzman, Brooke S.

2016-01-01

To develop a context for program-level design decisions pertaining to anthropogenic climate change, the authors studied the prevalence of courses focused on human-induced climate change in undergraduate marine science and environmental science degree programs in the United States. Of the 86 institutions and 125 programs the authors examined, 37%…

Methane Hydrate Field Program: Development of a Scientific Plan for a Methane Hydrate-Focused Marine Drilling, Logging and Coring Program

Energy Technology Data Exchange (ETDEWEB)

Myers, Greg [Consortium for Ocean Leadership, Washington, DC (United States)

2014-02-01

This final report document summarizes the activities undertaken and the output from three primary deliverables generated during this project. This fifteen month effort comprised numerous key steps including the creation of an international methane hydrate science team, determining and reporting the current state of marine methane hydrate research, convening an international workshop to collect the ideas needed to write a comprehensive Marine Methane Hydrate Field Research Plan and the development and publication of that plan. The following documents represent the primary deliverables of this project and are discussed in summary level detail in this final report: Historical Methane Hydrate Project Review Report; Methane Hydrate Workshop Report; Topical Report: Marine Methane Hydrate Field Research Plan; and Final Scientific/Technical Report.

Contribution of Anthropogenic and Natural Emissions to Global CH4 Balances by Utilizing δ13C-CH4 Observations in CarbonTracker Data Assimilation System (CTDAS)

Science.gov (United States)

Kangasaho, V. E.; Tsuruta, A.; Aalto, T.; Backman, L. B.; Houweling, S.; Krol, M. C.; Peters, W.; van der Laan-Luijkx, I. T.; Lienert, S.; Joos, F.; Dlugokencky, E. J.; Michael, S.; White, J. W. C.

2017-12-01

The atmospheric burden of CH4 has more than doubled since preindustrial time. Evaluating the contribution from anthropogenic and natural emissions to the global methane budget is of great importance to better understand the significance of different sources at the global scale, and their contribution to changes in growth rate of atmospheric CH4 before and after 2006. In addition, observations of δ13C-CH4 suggest an increase in natural sources after 2006, which matches the observed increase and variation of CH4 abudance. Methane emission sources can be identified using δ13C-CH4, because different sources produce methane with process-specific isotopic signatures. This study focuses on inversion model based estimates of global anthropogenic and natural methane emission rates to evaluate the existing methane emission estimates with a new δ13C-CH4 inversion system. In situ measurements of atmospheric methane and δ13C-CH4 isotopic signature, provided by the NOAA Global Monitoring Division and the Institute of Arctic and Alpine Research, will be assimilated into the CTDAS-13C-CH4. The system uses the TM5 atmospheric transport model as an observation operator, constrained by ECMWF ERA Interim meteorological fields, and off-line TM5 chemistry fields to account for the atmospheric methane sink. LPX-Bern DYPTOP ecosystem model is used for prior natural methane emissions from wetlands, peatlands and mineral soils, GFED v4 for prior fire emissions and EDGAR v4.2 FT2010 inventory for prior anthropogenic emissions. The EDGAR antropogenic emissions are re-divided into enteric fermentation and manure management, landfills and waste water, rice, coal, oil and gas, and residential emissions, and the trend of total emissions is scaled to match optimized anthropogenic emissions from CTE-CH4. In addition to these categories, emissions from termites and oceans are included. Process specific δ13C-CH4 isotopic signatures are assigned to each emission source to estimate 13CH4 fraction

Methane as a climate gas

Energy Technology Data Exchange (ETDEWEB)

Karlsdottir, S.

1996-03-01

This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Methane is a key component in the atmosphere where its concentration has increased rapidly since pre-industrial time. About 2/3 of it is caused by human activities. Changes in methane will affect the concentrations of other gases, and a model is a very important tool to study sensitivity due to changes in concentration of gases. The author used a three-dimensional global chemistry transport model to study the effect of changes in methane concentration on other trace gases. The model includes natural and anthropogenic emissions of NOx, CO, CH{sub 4} and non-methane hydrocarbons. Wet and dry deposition are also included. The chemical scheme in the model includes 49 compounds, 101 reactions, and 16 photolytic reactions. The trace gas concentrations are calculated every 30 min, using a quasi steady state approximation. Model calculations of three cases are reported and compared. Enhanced methane concentration will have strongest effect in remote regions. In polluted areas local chemistry will have remarked effect. The feedback was always positive. Average atmospheric lifetime calculated in the model was 7.6 years, which agrees with recent estimates based on observations. 8 refs.

Comparison of Landfill Methane Oxidation Measured Using Stable Isotope Analysis and CO2/CH4 Fluxes Measured by the Eddy Covariance Method

Science.gov (United States)

Xu, L.; Chanton, J.; McDermitt, D. K.; Li, J.; Green, R. B.

2015-12-01

Methane plays a critical role in the radiation balance and chemistry of the atmosphere. Globally, landfill methane emission contributes about 10-19% of the anthropogenic methane burden into the atmosphere. In the United States, 18% of annual anthropogenic methane emissions come from landfills, which represent the third largest source of anthropogenic methane emissions, behind enteric fermentation and natural gas and oil production. One uncertainty in estimating landfill methane emissions is the fraction of methane oxidized when methane produced under anaerobic conditions passes through the cover soil. We developed a simple stoichiometric model to estimate methane oxidation fraction when the anaerobic CO2 / CH4 production ratio is known, or can be estimated. The model predicts a linear relationship between CO2 emission rates and CH4 emission rates, where the slope depends on anaerobic CO2 / CH4 production ratio and the fraction of methane oxidized, and the intercept depends on non-methane-dependent oxidation processes. The model was tested using carbon dioxide emission rates (fluxes) and methane emission rates (fluxes) measured using the eddy covariance method over a one year period at the Turkey Run landfill in Georgia, USA. The CO2 / CH4 production ratio was estimated by measuring CO2 and CH4 concentrations in air sampled under anaerobic conditions deep inside the landfill. We also used a mass balance approach to independently estimate fractional oxidation based on stable isotope measurements (δ13C of methane) of gas samples taken from deep inside the landfill and just above the landfill surface. Results from the two independent methods agree well. The model will be described and methane oxidation will be discussed in relation to wind direction, location at the landfill, and age of the deposited refuse.

Methane reduction by plant pigments and antioxidants in rumen fluid involves modifications, e.g. hydrogenatioor degradation of the active compoundsn,

NARCIS (Netherlands)

Becker, P.M.; Wikselaar, van P.G.; Ilgenfritz, J.; Beekwilder, M.J.; Vos, de R.C.H.; Franz, C.H.; Zitterl-Eglseer, K.

2013-01-01

Methane is a major greenhouse gas, and ruminants cause about a quarter of all anthropogenic methane emissions. The objective of this study was to testplant secondary products in terms of their effects on methane production, and to follow active compounds analytically during incubation. In a simplifi

Formation of methane and nitrous oxide in plants

Science.gov (United States)

Keppler, Frank; Lenhart, Katharina

2017-04-01

Methane, the second important anthropogenic greenhouse gas after carbon dioxide, is the most abundant reduced organic compound in the atmosphere and plays a central role in atmospheric chemistry. The global atmospheric methane budget is determined by many natural and anthropogenic terrestrial and aquatic surface sources, balanced primarily by one major sink (hydroxyl radicals) in the atmosphere. Natural sources of atmospheric methane in the biosphere have until recently been attributed to originate solely from strictly anaerobic microbial processes in wetland soils and rice paddies, the intestines of termites and ruminants, human and agricultural waste, and from biomass burning, fossil fuel mining and geological sources including mud volcanoes and seeps. However, recent studies suggested that terrestrial vegetation, fungi and mammals may also produce methane without the help of methanogens and under aerobic conditions (e.g. Keppler et al. 2009, Wang et al. 2013). These novel sources have been termed "aerobic methane production" to distinguish them from the well-known anaerobic methane production pathway. Nitrous oxide is another important greenhouse gas and major source of ozone-depleting nitric oxide. About two thirds of nitrous oxide emissions are considered to originate from anthropogenic and natural terrestrial sources, and are almost exclusively related to microbial processes in soils and sediments. However, the global nitrous oxide budget still has major uncertainties since it is unclear if all major sources have been identified but also the emission estimates of the know sources and stratospheric sink are afflicted with high uncertainties. Plants contribute, although not yet quantified, to nitrous oxide emissions either indirectly as conduits of soil derived nitrous oxide (Pihlatie et al. 2005), or directly via generation of nitrous oxide in leaves (Dean & Harper 1986) or on the leaf surface induced by UV irradiation (Bruhn et al. 2014). Moreover, lichens

Methane Fluxes in West Siberia: 3-D Regional Model Simulation

International Nuclear Information System (INIS)

Jagovkina, S. V.; Karol, I. L.; Zubov, V. A.; Lagun, V. E.; Reshetnikov, A. I.; Rozanov, E. V.

2001-01-01

The West Siberian region is one of the main contributors of the atmospheric greenhouse gas methane due to the large areas of wetlands, rivers, lakes and numerous gas deposits situated there.But there are no reliable estimations of integral methane flux from this area into the atmosphere. For assessment of methane fluxes in West Siberia the specially constructed 3-D regional chemical transport model was applied. The 3-D distribution of methane is calculated on the basis of the current meteorological data fields(wind, temperature, geopotential) updated 4 times a day. The methane concentrations measured near the main gas fields of West Siberia in the summer season of 1999, were used for correction of methane flux intensity estimates obtained previously by comparison of measurements carried out in summer 1993 and 1996 with modelled methane mixing ratio distribution. This set of field and model experiments confirmed the preliminary conclusion about low leakage intensity: anthropogenic methane flux does not exceed 5-15% of total summer methane flux, estimated as 11-12 Mt CH 4 in summer from this region, in spite of the large areas of gas deposits located there

Identification, Attribution, and Quantification of Highly Heterogeneous Methane Sources Using a Mobile Stable Isotope Analyzer

Science.gov (United States)

Crosson, E.; Rella, C.; Cunningham, K.

2012-04-01

Despite methane's importance as a potent greenhouse gas second only to carbon dioxide in the magnitude of its contribution to global warming, natural contributions to the overall methane budget are only poorly understood. A big contributor to this gap in knowledge is the highly spatially and temporally heterogeneous nature of most natural (and for that matter anthropogenic) methane sources. This high degree of heterogeneity, where the methane emission rates can vary over many orders of magnitude on a spatial scale of meters or even centimeters, and over a temporal scale of minutes or even seconds, means that traditional methods of emissions flux estimation, such as flux chambers or eddy-covariance, are difficult or impossible to apply. In this paper we present new measurement methods that are capable of detecting, attributing, and quantifying emissions from highly heterogeneous sources. These methods take full advantage of the new class of methane concentration and stable isotope analyzers that are capable of laboratory-quality analysis from a mobile field platform in real time. In this paper we present field measurements demonstrating the real-time detection of methane 'hot spots,' attribution of the methane to a source process via real-time stable isotope analysis, and quantification of the emissions flux using mobile concentration measurements of the horizontal and vertical atmospheric dispersion, combined with atmospheric transport calculations. Although these techniques are applicable to both anthropogenic and natural methane sources, in this initial work we focus primarily on landfills and fugitive emissions from natural gas distribution, as these sources are better characterized, and because they provide a more reliable and stable source of methane for quantifying the measurement uncertainty inherent in the different methods. Implications of these new technologies and techniques are explored for the quantification of natural methane sources in a variety of

Methane oxidation coupled to oxygenic photosynthesis in anoxic waters

Science.gov (United States)

Milucka, Jana; Kirf, Mathias; Lu, Lu; Krupke, Andreas; Lam, Phyllis; Littmann, Sten; Kuypers, Marcel MM; Schubert, Carsten J

2015-01-01

Freshwater lakes represent large methane sources that, in contrast to the Ocean, significantly contribute to non-anthropogenic methane emissions to the atmosphere. Particularly mixed lakes are major methane emitters, while permanently and seasonally stratified lakes with anoxic bottom waters are often characterized by strongly reduced methane emissions. The causes for this reduced methane flux from anoxic lake waters are not fully understood. Here we identified the microorganisms and processes responsible for the near complete consumption of methane in the anoxic waters of a permanently stratified lake, Lago di Cadagno. Interestingly, known anaerobic methanotrophs could not be detected in these waters. Instead, we found abundant gamma-proteobacterial aerobic methane-oxidizing bacteria active in the anoxic waters. In vitro incubations revealed that, among all the tested potential electron acceptors, only the addition of oxygen enhanced the rates of methane oxidation. An equally pronounced stimulation was also observed when the anoxic water samples were incubated in the light. Our combined results from molecular, biogeochemical and single-cell analyses indicate that methane removal at the anoxic chemocline of Lago di Cadagno is due to true aerobic oxidation of methane fuelled by in situ oxygen production by photosynthetic algae. A similar mechanism could be active in seasonally stratified lakes and marine basins such as the Black Sea, where light penetrates to the anoxic chemocline. Given the widespread occurrence of seasonally stratified anoxic lakes, aerobic methane oxidation coupled to oxygenic photosynthesis might have an important but so far neglected role in methane emissions from lakes. PMID:25679533

Preliminary Evaluation of Method to Monitor Landfills Resilience against Methane Emission

Science.gov (United States)

Chusna, Noor Amalia; Maryono, Maryono

2018-02-01

Methane emission from landfill sites contribute to global warming and un-proper methane treatment can pose an explosion hazard. Stakeholder and government in the cities in Indonesia been found significant difficulties to monitor the resilience of landfill from methane emission. Moreover, the management of methane gas has always been a challenging issue for long waste management service and operations. Landfills are a significant contributor to anthropogenic methane emissions. This study conducted preliminary evaluation of method to manage methane gas emission by assessing LandGem and IPCC method. From the preliminary evaluation, this study found that the IPCC method is based on the availability of current and historical country specific data regarding the waste disposed of in landfills while from the LandGEM method is an automated tool for estimating emission rates for total landfill gas this method account total gas of methane, carbon dioxide and other. The method can be used either with specific data to estimate emissions in the site or default parameters if no site-specific data are available. Both of method could be utilize to monitor the methane emission from landfill site in cities of Central Java.

Iron-mediated anaerobic oxidation of methane in brackish coastal sediments.

Science.gov (United States)

Egger, Matthias; Rasigraf, Olivia; Sapart, Célia J; Jilbert, Tom; Jetten, Mike S M; Röckmann, Thomas; van der Veen, Carina; Bândă, Narcisa; Kartal, Boran; Ettwig, Katharina F; Slomp, Caroline P

2015-01-06

Methane is a powerful greenhouse gas and its biological conversion in marine sediments, largely controlled by anaerobic oxidation of methane (AOM), is a crucial part of the global carbon cycle. However, little is known about the role of iron oxides as an oxidant for AOM. Here we provide the first field evidence for iron-dependent AOM in brackish coastal surface sediments and show that methane produced in Bothnian Sea sediments is oxidized in distinct zones of iron- and sulfate-dependent AOM. At our study site, anthropogenic eutrophication over recent decades has led to an upward migration of the sulfate/methane transition zone in the sediment. Abundant iron oxides and high dissolved ferrous iron indicate iron reduction in the methanogenic sediments below the newly established sulfate/methane transition. Laboratory incubation studies of these sediments strongly suggest that the in situ microbial community is capable of linking methane oxidation to iron oxide reduction. Eutrophication of coastal environments may therefore create geochemical conditions favorable for iron-mediated AOM and thus increase the relevance of iron-dependent methane oxidation in the future. Besides its role in mitigating methane emissions, iron-dependent AOM strongly impacts sedimentary iron cycling and related biogeochemical processes through the reduction of large quantities of iron oxides.

Historical methane hydrate project review

Science.gov (United States)

Collett, Timothy; Bahk, Jang-Jun; Frye, Matt; Goldberg, Dave; Husebo, Jarle; Koh, Carolyn; Malone, Mitch; Shipp, Craig; Torres, Marta

2013-01-01

In 1995, U.S. Geological Survey made the first systematic assessment of the volume of natural gas stored in the hydrate accumulations of the United States. That study, along with numerous other studies, has shown that the amount of gas stored as methane hydrates in the world greatly exceeds the volume of known conventional gas resources. However, gas hydrates represent both a scientific and technical challenge and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of gas hydrates in nature, (2) assessing the volume of natural gas stored within various gas hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural gas hydrates, and (5) analyzing the effects of methane hydrate on drilling safety.Methane hydrates are naturally occurring crystalline substances composed of water and gas, in which a solid water-­‐lattice holds gas molecules in a cage-­‐like structure. The gas and water becomes a solid under specific temperature and pressure conditions within the Earth, called the hydrate stability zone. Other factors that control the presence of methane hydrate in nature include the source of the gas included within the hydrates, the physical and chemical controls on the migration of gas with a sedimentary basin containing methane hydrates, the availability of the water also included in the hydrate structure, and the presence of a suitable host sediment or “reservoir”. The geologic controls on the occurrence of gas hydrates have become collectively known as the “methane hydrate petroleum system”, which has become the focus of numerous hydrate research programs.Recognizing the importance of methane hydrate research and the need for a coordinated

Warming Increases the Proportion of Primary Production Emitted as Methane from Freshwater Mesocosms

OpenAIRE

2010-01-01

Abstract Methane and carbon dioxide are the dominant gaseous end products of the remineralisation of organic carbon and also the two largest contributors to the anthropogenic greenhouse effect. We investigated whether warming altered the balance of methane efflux relative to primary production and ecosystem respiration in a freshwater mesocosm experiment. Whole ecosystem CH4 efflux was strongly related to temperature with an apparent activation energy of 0.85eV. Furthermore, CH4 ef...

Atmospheric Radiation Measurement Program facilities newsletter, July 2001.; TOPICAL

International Nuclear Information System (INIS)

Holdridge, D. J.

2001-01-01

Global Warming and Methane-Global warming, an increase in Earth's near-surface temperature, is believed to result from the buildup of what scientists refer to as ''greenhouse gases.'' These gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, perfluorocarbons, hydrofluoro-carbons, and sulfur hexafluoride. Greenhouse gases can absorb outgoing infrared (heat) radiation and re-emit it back to Earth, warming the surface. Thus, these gases act like the glass of a greenhouse enclosure, trapping infrared radiation inside and warming the space. One of the more important greenhouse gases is the naturally occurring hydrocarbon methane. Methane, a primary component of natural gas, is the second most important contributor to the greenhouse effect (after carbon dioxide). Natural sources of methane include wetlands, fossil sources, termites, oceans, fresh-waters, and non-wetland soils. Methane is also produced by human-related (or anthropogenic) activities such as fossil fuel production, coal mining, rice cultivation, biomass burning, water treatment facilities, waste management operations and landfills, and domesticated livestock operations (Figure 1). These anthropogenic activities account for approximately 70% of the methane emissions to the atmosphere. Methane is removed naturally from the atmosphere in three ways. These methods, commonly referred to as sinks, are oxidation by chemical reaction with tropospheric hydroxyl ion, oxidation within the stratosphere, and microbial uptake by soils. In spite of their important role in removing excess methane from the atmosphere, the sinks cannot keep up with global methane production. Methane concentrations in the atmosphere have increased by 145% since 1800. Increases in atmospheric methane roughly parallel world population growth, pointing to anthropogenic sources as the cause (Figure 2). Increases in the methane concentration reduce Earth's natural cooling efficiency by trapping more of the outgoing

Shallow Gas Migration along Hydrocarbon Wells-An Unconsidered, Anthropogenic Source of Biogenic Methane in the North Sea.

Science.gov (United States)

Vielstädte, Lisa; Haeckel, Matthias; Karstens, Jens; Linke, Peter; Schmidt, Mark; Steinle, Lea; Wallmann, Klaus

2017-09-05

Shallow gas migration along hydrocarbon wells constitutes a potential methane emission pathway that currently is not recognized in any regulatory framework or greenhouse gas inventory. Recently, the first methane emission measurements at three abandoned offshore wells in the Central North Sea (CNS) were conducted showing that considerable amounts of biogenic methane originating from shallow gas accumulations in the overburden of deep reservoirs were released by the boreholes. Here, we identify numerous wells poking through shallow gas pockets in 3-D seismic data of the CNS indicating that about one-third of the wells may leak, potentially releasing a total of 3-17 kt of methane per year into the North Sea. This poses a significant contribution to the North Sea methane budget. A large fraction of this gas (∼42%) may reach the atmosphere via direct bubble transport (0-2 kt yr -1 ) and via diffusive exchange of methane dissolving in the surface mixed layer (1-5 kt yr -1 ), as indicated by numerical modeling. In the North Sea and in other hydrocarbon-prolific provinces of the world shallow gas pockets are frequently observed in the sedimentary overburden and aggregate leakages along the numerous wells drilled in those areas may be significant.

MERLIN: a Franco-German LIDAR space mission for atmospheric methane

Science.gov (United States)

Bousquet, P.; Ehret, G.; Pierangelo, C.; Marshall, J.; Bacour, C.; Chevallier, F.; Gibert, F.; Armante, R.; Crevoisier, C. D.; Edouart, D.; Esteve, F.; Julien, E.; Kiemle, C.; Alpers, M.; Millet, B.

2017-12-01

The Methane Remote Sensing Lidar Mission (MERLIN), currently in phase C, is a joint cooperation between France and Germany on the development, launch and operation of a space LIDAR dedicated to the retrieval of total weighted methane (CH4) atmospheric columns. Atmospheric methane is the second most potent anthropogenic greenhouse gas, contributing 20% to climate radiative forcing but also plying an important role in atmospheric chemistry as a precursor of tropospheric ozone and low-stratosphere water vapour. Its short lifetime ( 9 years) and the nature and variety of its anthropogenic sources also offer interesting mitigation options in regards to the 2° objective of the Paris agreement. For the first time, measurements of atmospheric composition will be performed from space thanks to an IPDA (Integrated Path Differential Absorption) LIDAR (Light Detecting And Ranging), with a precision (target ±27 ppb for a 50km aggregation along the trace) and accuracy (target recall the MERLIN objectives and mission characteristics. We also propose an end-to-end error analysis, from the causes of random and systematic errors of the instrument, of the platform and of the data treatment, to the error on methane emissions. To do so, we propose an OSSE analysis (observing system simulation experiment) to estimate the uncertainty reduction on methane emissions brought by MERLIN XCH4. The originality of our inversion system is to transfer both random and systematic errors from the observation space to the flux space, thus providing more realistic error reductions than usually provided in OSSE only using the random part of errors. Uncertainty reductions are presented using two different atmospheric transport models, TM3 and LMDZ, and compared with error reduction achieved with the GOSAT passive mission.

The MIS 11 – MIS 1 analogy, southern European vegetation, atmospheric methane and the

Directory of Open Access Journals (Sweden)

P. C. Tzedakis

2010-03-01

Full Text Available Marine Isotope Stage (MIS 11 has been considered a potential analogue for the Holocene and its future evolution. However, a dichotomy has emerged over the precise chronological alignment of the two intervals, with one solution favouring a synchronization of the precession signal and another of the obliquity signal. The two schemes lead to different implications over the natural length of the current interglacial and the underlying causes of the evolution of greenhouse gas concentrations. Here, the close coupling observed between changes in southern European tree populations and atmospheric methane concentrations in previous interglacials is used to evaluate the natural vs. anthropogenic contribution to Holocene methane emissions and assess the two alignment schemes. Comparison of the vegetation trends in MIS 1 and MIS 11 favours a precessional alignment, which would suggest that the Holocene is nearing the end of its natural course. This, combined with the divergence between methane concentrations and temperate tree populations after 5 kyr BP, provides some support for the notion that the Holocene methane trend may be anomalous compared to previous interglacials. In contrast, comparison of MIS 1 with MIS 19, which may represent a closer astronomical analogue than MIS 11, leads to substantially different conclusions on the projected natural duration of the current interglacial and the extent of the anthropogenic contribution to the Holocene methane budget. As answers vary with the choice of analogue, resolution of these issues using past interglacials remains elusive.

The isotopic composition of methane in polar ice cores

Science.gov (United States)

Craig, H.; Chou, C. C.; Welhan, J. A.; Stevens, C. M.; Engelkemeir, A.

1988-01-01

Air bubbles in polar ice cores indicate that about 300 years ago the atmospheric mixing ratio of methane began to increase rapidly. Today the mixing ratio is about 1.7 parts per million by volume, and, having doubled once in the past several hundred years, it will double again in the next 60 years if current rates continue. Carbon isotope ratios in methane up to 350 years in age have been measured with as little as 25 kilograms of polar ice recovered in 4-meter-long ice-core segments. The data show that: (1) in situ microbiology or chemistry has not altered the ice-core methane concentrations, and (2) that the carbon-13 to carbon-12 ratio of atmospheric CH4 in ice from 100 years and 300 years ago was about 2 per mil lower than at present. Atmospheric methane has a rich spectrum of isotopic sources: the ice-core data indicate that anthropogenic burning of the earth's biomass is the principal cause of the recent C-13H4 enrichment, although other factors may also contribute.

Mobile mapping of methane emissions and isoscapes

Science.gov (United States)

Takriti, Mounir; Ward, Sue; Wynn, Peter; Elias, Dafydd; McNamara, Niall

2017-04-01

Methane (CH4) is a potent greenhouse gas emitted from a variety of natural and anthropogenic sources. It is crucial to accurately and efficiently detect CH4 emissions and identify their sources to improve our understanding of changing emission patterns as well as to identify ways to curtail their release into the atmosphere. However, using established methods this can be challenging as well as time and resource intensive due to the temporal and spatial heterogeneity of many sources. To address this problem, we have developed a vehicle mounted mobile system that combines high precision CH4 measurements with isotopic mapping and dual isotope source characterisation. We here present details of the development and testing of a unique system for the detection and isotopic analysis of CH4 plumes built around a Picarro isotopic (13C/12C) gas analyser and a high precision Los Gatos greenhouse gas analyser. Combined with micrometeorological measurements and a mechanism for collecting discrete samples for high precision dual isotope (13C/12C, 2H/1H) analysis the system enables mapping of concentrations as well as directional and isotope based source verification. We then present findings from our mobile methane surveys around the North West of England. This area includes a variety of natural and anthropogenic methane sources within a relatively small geographical area, including livestock farming, urban and industrial gas infrastructure, landfills and waste water treatment facilities, and wetlands. We show that the system was successfully able to locate leaks from natural gas infrastructure and emissions from agricultural activities and to distinguish isotope signatures from these sources.

Gridded National Inventory of U.S. Methane Emissions

Science.gov (United States)

Maasakkers, Joannes D.; Jacob, Daniel J.; Sulprizio, Melissa P.; Turner, Alexander J.; Weitz, Melissa; Wirth, Tom; Hight, Cate; DeFigueiredo, Mark; Desai, Mausami; Schmeltz, Rachel;

Evaluating Bay Area Methane Emission Inventory

Energy Technology Data Exchange (ETDEWEB)

Fischer, Marc [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jeong, Seongeun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-03-01

As a regulatory agency, evaluating and improving estimates of methane (CH4) emissions from the San Francisco Bay Area is an area of interest to the Bay Area Air Quality Management District (BAAQMD). Currently, regional, state, and federal agencies generally estimate methane emissions using bottom-up inventory methods that rely on a combination of activity data, emission factors, biogeochemical models and other information. Recent atmospheric top-down measurement estimates of methane emissions for the US as a whole (e.g., Miller et al., 2013) and in California (e.g., Jeong et al., 2013; Peischl et al., 2013) have shown inventories underestimate total methane emissions by ~ 50% in many areas of California, including the SF Bay Area (Fairley and Fischer, 2015). The goal of this research is to provide information to help improve methane emission estimates for the San Francisco Bay Area. The research effort builds upon our previous work that produced methane emission maps for each of the major source sectors as part of the California Greenhouse Gas Emissions Measurement (CALGEM) project (http://calgem.lbl.gov/prior_emission.html; Jeong et al., 2012; Jeong et al., 2013; Jeong et al., 2014). Working with BAAQMD, we evaluate the existing inventory in light of recently published literature and revise the CALGEM CH4 emission maps to provide better specificity for BAAQMD. We also suggest further research that will improve emission estimates. To accomplish the goals, we reviewed the current BAAQMD inventory, and compared its method with those from the state inventory from the California Air Resources Board (CARB), the CALGEM inventory, and recent published literature. We also updated activity data (e.g., livestock statistics) to reflect recent changes and to better represent spatial information. Then, we produced spatially explicit CH4 emission estimates on the 1-km modeling grid used by BAAQMD. We present the detailed activity data, methods and derived emission maps by sector

Estimates and Predictions of Methane Emissions from Wastewater in China from 2000 to 2020

Science.gov (United States)

Du, Mingxi; Zhu, Qiuan; Wang, Xiaoge; Li, Peng; Yang, Bin; Chen, Huai; Wang, Meng; Zhou, Xiaolu; Peng, Changhui

2018-02-01

Methane accounts for 20% of the global warming caused by greenhouse gases, and wastewater is a major anthropogenic source of methane. Based on the Intergovernmental Panel on Climate Change greenhouse gas inventory guidelines and current research findings, we calculated the amount of methane emissions from 2000 to 2014 that originated from wastewater from different provinces in China. Methane emissions from wastewater increased from 1349.01 to 3430.03 Gg from 2000 to 2014, and the mean annual increase was 167.69 Gg. The methane emissions from industrial wastewater treated by wastewater treatment plants (EIt) accounted for the highest proportion of emissions. We also estimated the future trend of industrial wastewater methane emissions using the artificial neural network model. A comparison of the emissions for the years 2020, 2010, and 2000 showed an increasing trend in methane emissions in China and a spatial transition of industrial wastewater emissions from eastern and southern regions to central and southwestern regions and from coastal regions to inland regions. These changes were caused by changes in economics, demographics, and relevant policies.

CYANOBACTERIA FOR MITIGATING METHANE EMISSION FROM SUBMERGED PADDY FIELDS

Energy Technology Data Exchange (ETDEWEB)

Upasana Mishra; Shalini Anand [Department of Environmental Studies, Inderprastha Engineering College, Sahibabad, Ghaziabad (India)

2008-09-30

Atmospheric methane, a potent greenhouse gas with high absorption potential for infrared radiation, is responsible for one forth of the total anticipated warming. It is forming a major part of green house gases, next after carbon dioxide. Its concentration has been increasing alarmingly on an average at the rate of one percent per year. Atmospheric methane, originating mainly from biogenic sources such as paddy fields, natural wetlands and landfills, accounts for 15-20% of the world's total anthropogenic methane emission. With intensification of rice cultivation in coming future, methane emissions from paddy fields are anticipated to increase. India's share in world's rice production is next after to China and likewise total methane emission from paddy fields also. Methane oxidation through planktophytes, particularly microalgae which are autotrophic and abundant in rice rhizospheres, hold promise in controlling methane emission from submerged paddy fields. The present study is focused on the role of nitrogen fixing, heterocystous cyanobacteria and Azolla (a water fern harboring a cyanobacterium Anabaena azollae) as biological sink for headspace concentration of methane in flooded soils. In this laboratory study, soil samples containing five potent nitrogen fixer cyanobacterial strains from paddy fields, were examined for their methane reducing potential. Soil sample without cyanobacterial strain was tested and taken as control. Anabaena sp. was found most effective in inhibiting methane concentration by 5-6 folds over the control. Moist soil cores treated with chemical nitrogen, urea, in combination with cyanobacteria mixture, Azolla microphylla or cyanobacteria mixture plus Azolla microphylla exhibited significance reduction in the headspace concentration of methane than the soil cores treated with urea alone. Contrary to other reports, this study also demonstrates that methane oxidation in soil core samples from paddy fields was stimulated by

Infrared radiation models for atmospheric methane

Science.gov (United States)

Cess, R. D.; Kratz, D. P.; Caldwell, J.; Kim, S. J.

1986-01-01

Mutually consistent line-by-line, narrow-band and broad-band infrared radiation models are presented for methane, a potentially important anthropogenic trace gas within the atmosphere. Comparisons of the modeled band absorptances with existing laboratory data produce the best agreement when, within the band models, spurious band intensities are used which are consistent with the respective laboratory data sets, but which are not consistent with current knowledge concerning the intensity of the infrared fundamental band of methane. This emphasizes the need for improved laboratory band absorptance measurements. Since, when applied to atmospheric radiation calculations, the line-by-line model does not require the use of scaling approximations, the mutual consistency of the band models provides a means of appraising the accuracy of scaling procedures. It is shown that Curtis-Godson narrow-band and Chan-Tien broad-band scaling provide accurate means of accounting for atmospheric temperature and pressure variations.

Constructing a Spatially Resolved Methane Emission Inventory of Natural Gas Production and Distribution over Contiguous United States

Science.gov (United States)

Li, X.; Omara, M.; Adams, P. J.; Presto, A. A.

2017-12-01

Methane is the second most powerful greenhouse gas after Carbon Dioxide. The natural gas production and distribution accounts for 23% of the total anthropogenic methane emissions in the United States. The boost of natural gas production in U.S. in recent years poses a potential concern of increased methane emissions from natural gas production and distribution. The Emission Database for Global Atmospheric Research (Edgar) v4.2 and the EPA Greenhouse Gas Inventory (GHGI) are currently the most commonly used methane emission inventories. However, recent studies suggested that both Edgar v4.2 and the EPA GHGI largely underestimated the methane emission from natural gas production and distribution in U.S. constrained by both ground and satellite measurements. In this work, we built a gridded (0.1° Latitude ×0.1° Longitude) methane emission inventory of natural gas production and distribution over the contiguous U.S. using emission factors measured by our mobile lab in the Marcellus Shale, the Denver-Julesburg Basin, and the Uintah Basin, and emission factors reported from other recent field studies for other natural gas production regions. The activity data (well location and count) are mostly obtained from the Drillinginfo, the EPA Greenhouse Gas Reporting Program (GHGRP) and the U.S. Energy Information Administration (EIA). Results show that the methane emission from natural gas production and distribution estimated by our inventory is about 20% higher than the EPA GHGI, and in some major natural gas production regions, methane emissions estimated by the EPA GHGI are significantly lower than our inventory. For example, in the Marcellus Shale, our estimated annual methane emission in 2015 is 600 Gg higher than the EPA GHGI. We also ran the GEOS-Chem methane simulation to estimate the methane concentration in the atmosphere with our built inventory, the EPA GHGI and the Edgar v4.2 over the nested North American Domain. These simulation results showed differences in

High Time Resolution Measurements of Methane Fluxes From Enteric Fermentation in Cattle Rumen

Science.gov (United States)

Floerchinger, C. R.; Herndon, S.; Fortner, E.; Roscioli, J. R.; Kolb, C. E.; Knighton, W. B.; Molina, L. T.; Zavala, M.; Castelán, O.; Ku Vera, J.; Castillo, E.

2013-12-01

Methane accounts for roughly 20% of the global radiative climate forcing in the last two and a half centuries. Methane emissions arise from a number of anthropogenic and biogenic sources. In some areas enteric fermentation in livestock produces over 90% of agricultural methane. In the spring of 2013, as a part of the Short Lived Climate Forcer-Mexico field campaign, the Aerodyne Mobile Laboratory in partnership with the Molina Center for the Environment studied methane production associated with enteric fermentation in the rumen of cattle. A variety of different breeds and stocks being raised in two agricultural and veterinary research facilities located in different areas of Mexico were examined. Methane fluxes were quantified using two methods: 1) an atmospherically stable gaseous tracer release was collocated with small herds in a pasture, allowing tracer ratio flux measurements; 2) respiratory CO2 was measured in tandem with methane in the breath of individual animals allowing methane production to be related to metabolism. The use of an extensive suite of very high time response instruments allows for differentiation of individual methane producing rumination events and respiratory CO2 from possible background interferences. The results of these studies will be presented and compared to data from traditional chamber experiments.

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D

1983-01-01

Most atmospheric methane originates by bacterial processes in anaerobic environments within the soil, which become more productive with increases in ambient temperature. A warming of the climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is likely to increase methane concentrations within the atmosphere, possibly leading to further heating, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. Investigators explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although they found this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity that should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/.

The Early Anthropogenic Hypothesis: Top-Down and Bottom-up Evidence

Science.gov (United States)

Ruddiman, W. F.

2014-12-01

Two complementary lines of evidence support the early anthropogenic hypothesis. Top-down evidence comes from comparing Holocene greenhouse-gas trends with those during equivalent intervals of previous interglaciations. The increases in CO2 and CH4 during the late Holocene are anomalous compared to the decreasing trends in a stacked average of previous interglaciations, thereby supporting an anthropogenic origin. During interglacial stage 19, the closest Holocene insolation analog, CO2 fell to 245 ppm by the time equivalent to the present, in contrast to the observed pre-industrial rise to 280-285 ppm. The 245-ppm level measured in stage 19 falls at the top of the natural range predicted by the original anthropogenic hypothesis of Ruddiman (2003). Bottom-up evidence comes from a growing list of archeological and other compilations showing major early anthropogenic transformations of Earth's surface. Key examples include: efforts by Dorian Fuller and colleagues mapping the spread of irrigated rice agriculture across southern Asia and its effects on CH4 emissions prior to the industrial era; an additional effort by Fuller showing the spread of methane-emitting domesticated livestock across Asia and Africa (coincident with the spread of fertile crescent livestock across Europe); historical compilations by Jed Kaplan and colleagues documenting very high early per-capita forest clearance in Europe, thus underpinning simulations of extensive pre-industrial clearance and large CO2 emissions; and wide-ranging studies by Erle Ellis and colleagues of early anthropogenic land transformations in China and elsewhere.

Direct measurements show decreasing methane emissions from natural gas local distribution systems in the United States.

Science.gov (United States)

Lamb, Brian K; Edburg, Steven L; Ferrara, Thomas W; Howard, Touché; Harrison, Matthew R; Kolb, Charles E; Townsend-Small, Amy; Dyck, Wesley; Possolo, Antonio; Whetstone, James R

2015-04-21

Fugitive losses from natural gas distribution systems are a significant source of anthropogenic methane. Here, we report on a national sampling program to measure methane emissions from 13 urban distribution systems across the U.S. Emission factors were derived from direct measurements at 230 underground pipeline leaks and 229 metering and regulating facilities using stratified random sampling. When these new emission factors are combined with estimates for customer meters, maintenance, and upsets, and current pipeline miles and numbers of facilities, the total estimate is 393 Gg/yr with a 95% upper confidence limit of 854 Gg/yr (0.10% to 0.22% of the methane delivered nationwide). This fraction includes emissions from city gates to the customer meter, but does not include other urban sources or those downstream of customer meters. The upper confidence limit accounts for the skewed distribution of measurements, where a few large emitters accounted for most of the emissions. This emission estimate is 36% to 70% less than the 2011 EPA inventory, (based largely on 1990s emission data), and reflects significant upgrades at metering and regulating stations, improvements in leak detection and maintenance activities, as well as potential effects from differences in methodologies between the two studies.

A Compact, Low Resource Instrument to Measure Atmospheric Methane and Carbon Dioxide From Orbit

Science.gov (United States)

Rafkin, Scot; Davis, Michael; Varner, Ruth; Basu, Sourish; Bruhwiler, Lori; Luspay-Kuti, Adrienn; Mandt, Kathy; Roming, Pete; Soto, Alejandro; Tapley, Mark

2017-04-01

Methane is the second most important radiatively active trace gas forcing anthropogenic climate change. Methane has ˜28 times more warming potential than carbon dioxide on a 100-year time horizon, and the background atmospheric concentration of methane has increased by more than 150% compared to pre-industrial levels. The increase in methane abundance is driven by a combination of direct human activity, such as fossil fuel extraction and agriculture, and natural feedback processes that respond to human-induced climate change, such as increased wetland production. Accurate accounting of the exchange between the atmosphere and the natural and anthropogenic methane reservoirs is necessary to predict how methane concentration will increase going forward, how that increase will modulate the natural methane cycle, and how effective policy decisions might be at mitigating methane-induced climate change. Monitoring and quantifying methane source intensity and spatial-temporal variability has proven challenging; there are unresolved and scientifically significant discrepancies between flux estimates based on limited surface measurements (the so-called "bottom-up" method) and the values derived from limited, remotely-sensed estimates from orbit and modeling (the so-called "top-down" method). A major source of the discrepancy between bottom-up and top-down estimates is likely a result of insufficient accuracy and resolution of space-based instrumentation. Methane releases, especially anthropogenic sources, are often at kilometer-scale (or less), whereas past remote sensing instruments have at least an order of magnitude greater footprint areas. Natural sources may be larger in areal extent, but the enhancement over background levels can be just a few percent, which demands high spectral resolution and signal-to-noise ratios from monitoring instrumentation. In response to the need for higher performance space-based methane monitoring, we have developed a novel, compact, low

Global health benefits of mitigating ozone pollution with methane emission controls.

Science.gov (United States)

West, J Jason; Fiore, Arlene M; Horowitz, Larry W; Mauzerall, Denise L

2006-03-14

Methane (CH(4)) contributes to the growing global background concentration of tropospheric ozone (O(3)), an air pollutant associated with premature mortality. Methane and ozone are also important greenhouse gases. Reducing methane emissions therefore decreases surface ozone everywhere while slowing climate warming, but although methane mitigation has been considered to address climate change, it has not for air quality. Here we show that global decreases in surface ozone concentrations, due to methane mitigation, result in substantial and widespread decreases in premature human mortality. Reducing global anthropogenic methane emissions by 20% beginning in 2010 would decrease the average daily maximum 8-h surface ozone by approximately 1 part per billion by volume globally. By using epidemiologic ozone-mortality relationships, this ozone reduction is estimated to prevent approximately 30,000 premature all-cause mortalities globally in 2030, and approximately 370,000 between 2010 and 2030. If only cardiovascular and respiratory mortalities are considered, approximately 17,000 global mortalities can be avoided in 2030. The marginal cost-effectiveness of this 20% methane reduction is estimated to be approximately 420,000 US dollars per avoided mortality. If avoided mortalities are valued at 1 US dollars million each, the benefit is approximately 240 US dollars per tone of CH(4) ( approximately 12 US dollars per tone of CO(2) equivalent), which exceeds the marginal cost of the methane reduction. These estimated air pollution ancillary benefits of climate-motivated methane emission reductions are comparable with those estimated previously for CO(2). Methane mitigation offers a unique opportunity to improve air quality globally and can be a cost-effective component of international ozone management, bringing multiple benefits for air quality, public health, agriculture, climate, and energy.

Source partitioning of methane emissions and its seasonality in the U.S. Midwest

Science.gov (United States)

Zichong Chen; Timothy J. Griffis; John M. Baker; Dylan B. Millet; Jeffrey D. Wood; Edward J. Dlugokencky; Arlyn E. Andrews; Colm Sweeney; Cheng Hu; Randall K. Kolka

2018-01-01

The methane (CH4) budget and its source partitioning are poorly constrained in the Midwestern United States. We used tall tower (185 m) aerodynamic flux measurements and atmospheric scale factor Bayesian inversions to constrain the monthly budget and to partition the total budget into natural (e.g., wetlands) and anthropogenic (e.g., livestock,...

Vista-LA: Mapping methane-emitting infrastructure in the Los Angeles megacity

Science.gov (United States)

Carranza, Valerie; Rafiq, Talha; Frausto-Vicencio, Isis; Hopkins, Francesca M.; Verhulst, Kristal R.; Rao, Preeti; Duren, Riley M.; Miller, Charles E.

2018-03-01

Methane (CH4) is a potent greenhouse gas (GHG) and a critical target of climate mitigation efforts. However, actionable emission reduction efforts are complicated by large uncertainties in the methane budget on relevant scales. Here, we present Vista, a Geographic Information System (GIS)-based approach to map potential methane emissions sources in the South Coast Air Basin (SoCAB) that encompasses Los Angeles, an area with a dense, complex mixture of methane sources. The goal of this work is to provide a database that, together with atmospheric observations, improves methane emissions estimates in urban areas with complex infrastructure. We aggregated methane source location information into three sectors (energy, agriculture, and waste) following the frameworks used by the State of California GHG Inventory and the Intergovernmental Panel on Climate Change (IPCC) Guidelines for GHG Reporting. Geospatial modeling was applied to publicly available datasets to precisely geolocate facilities and infrastructure comprising major anthropogenic methane source sectors. The final database, Vista-Los Angeles (Vista-LA), is presented as maps of infrastructure known or expected to emit CH4. Vista-LA contains over 33 000 features concentrated on Vista-LA is used as a planning and analysis tool for atmospheric measurement surveys of methane sources, particularly for airborne remote sensing, and methane hotspot detection using regional observations. This study represents a first step towards developing an accurate, spatially resolved methane flux estimate for point sources in SoCAB, with the potential to address discrepancies between bottom-up and top-down methane emissions accounting in this region. The Vista-LA datasets and associated metadata are available from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC; https://doi.org/10.3334/ORNLDAAC/1525).

Direct measurements of methane emissions from abandoned oil and gas wells in Pennsylvania.

Science.gov (United States)

Kang, Mary; Kanno, Cynthia M; Reid, Matthew C; Zhang, Xin; Mauzerall, Denise L; Celia, Michael A; Chen, Yuheng; Onstott, Tullis C

2014-12-23

Abandoned oil and gas wells provide a potential pathway for subsurface migration and emissions of methane and other fluids to the atmosphere. Little is known about methane fluxes from the millions of abandoned wells that exist in the United States. Here, we report direct measurements of methane fluxes from abandoned oil and gas wells in Pennsylvania, using static flux chambers. A total of 42 and 52 direct measurements were made at wells and at locations near the wells ("controls") in forested, wetland, grassland, and river areas in July, August, October 2013 and January 2014, respectively. The mean methane flow rates at these well locations were 0.27 kg/d/well, and the mean methane flow rate at the control locations was 4.5 × 10(-6) kg/d/location. Three out of the 19 measured wells were high emitters that had methane flow rates that were three orders of magnitude larger than the median flow rate of 1.3 × 10(-3) kg/d/well. Assuming the mean flow rate found here is representative of all abandoned wells in Pennsylvania, we scaled the methane emissions to be 4-7% of estimated total anthropogenic methane emissions in Pennsylvania. The presence of ethane, propane, and n-butane, along with the methane isotopic composition, indicate that the emitted methane is predominantly of thermogenic origin. These measurements show that methane emissions from abandoned oil and gas wells can be significant. The research required to quantify these emissions nationally should be undertaken so they can be accurately described and included in greenhouse gas emissions inventories.

The Effects of Surface Properties and Albedo on Methane Retrievals with the Airborne Visible/Infrared Imaging Spectrometer Next Generation (AVIRIS-NG)

Science.gov (United States)

Ayasse, A.; Thorpe, A. K.; Roberts, D. A.

2017-12-01

Atmospheric methane has increased by a factor of 2.5 since the beginning of the industrial era in response to anthropogenic emissions (Ciais et al., 2013). Although it is less abundant than carbon dioxide it is 86 time more potent on a 20 year time scale (Myhre et al., 2013) and is therefore responsible for about 20% of the total global warming induced by anthropogenic greenhouse gasses (Kirschke et al., 2013). Given the importance of methane to global climate change, monitoring and measuring methane emissions using techniques such as remote sensing is of increasing interest. Recently the Airborne Visible-Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG) has proven to be a valuable instrument for quantitative mapping of methane plumes (Frankenberg et al., 2016; Thorpe et al., 2016; Thompson et al., 2015). In this study, we applied the Iterative Maximum a Posterior Differential Optical Spectroscopy (IMAP-DOAS) methane retrieval algorithm to a synthetic image with variable methane concentrations, albedo, and land cover. This allowed for characterizing retrieval performance, including potential sensitivity to variable land cover, low albedo surfaces, and surfaces known to cause spurious signals. We conclude that albedo had little influence on the IMAP-DOAS results except at very low radiance levels. Water (without sun glint) was found to be the most challenging surface for methane retrievals while hydrocarbons and some green vegetation also caused error. Understanding the effect of surface properties on methane retrievals is important given the increased use of AVIRIS-NG to map gas plumes over diverse locations and methane sources. This analysis could be expanded to include additional gas species like carbon dioxide and to further investigate gas sensitivity of proposed instruments for dedicated gas mapping from airborne and spaceborne platforms.

Technologies for the bioconversion of methane into more valuable products.

Science.gov (United States)

Cantera, Sara; Muñoz, Raúl; Lebrero, Raquel; López, Juan Carlos; Rodríguez, Yadira; García-Encina, Pedro Antonio

2018-04-01

Methane, with a global warming potential twenty five times higher than that of CO 2 is the second most important greenhouse gas emitted nowadays. Its bioconversion into microbial molecules with a high retail value in the industry offers a potential cost-efficient and environmentally friendly solution for mitigating anthropogenic diluted CH 4 -laden streams. Methane bio-refinery for the production of different compounds such as ectoine, feed proteins, biofuels, bioplastics and polysaccharides, apart from new bioproducts characteristic of methanotrophic bacteria, has been recently tested in discontinuous and continuous bioreactors with promising results. This review constitutes a critical discussion about the state-of-the-art of the potential and research niches of biotechnologies applied in a CH 4 biorefinery approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

EPA's landfill methane outreach program: demonstration of the new E-PLUS economic evaluation model: future trends and activities

International Nuclear Information System (INIS)

Kerr, T.; Paleyanda, P.; Forbes, C.D.

1997-01-01

Landfills contain most of the municipal solid waste (MSW) generated in the United States. As this landfilled MSW decomposes, it produces landfill gas (LFG), containing approximately 50% methane, 43-47% carbon dioxide, and 3-7% non-methane organic compounds (NMOCs). Federal regulations require affected landfills to collect and combust their LFG emissions in order to destroy NMOCs, as they are important precursors to local smog. Since 1994, the U.S. Environmental Protection Agency's Landfill Methane Outreach Program (LMOP) has been working to promote LFG-to-energy as a cost-effective way to reduce emissions of methane - a potent greenhouse gas. The LMOP's latest tool is ''E-PLUS'', Windows-compatible software that can be used to screen potential LFG-to-energy projects. E-PLUS, the Energy Project Landfill Gas Utilization Software, is capable of evaluating the economic feasibility of two energy recovery technologies based on potential LFG emissions estimates. This paper provides an overview of E-PLUS and describes its features and functions in detail. (author)

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D [State Univ. of New York at Stony Brook, Stony Brook, NY (USA). Lab. for Planetary Atmospheres Research

1983-01-01

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. We have explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although we find this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity which should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/ itself. It would thus seem useful to carefully monitor future atmospheric CH/sub 4/ concentrations.

Impact of a global warming on biospheric sources of methane and its climatic consequences

Energy Technology Data Exchange (ETDEWEB)

Hameed, S; Cess, R D

1983-02-01

Most of atmospheric methane originates by bacterial processes in anaerobic environments within the soil which are found to become more productive with increases in ambient temperature. A warming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to further heating of the atmosphere, since both methane and ozone (which is generated in the troposphere from reactions of methane) have greenhouse effects. We have explored this feedback mechanism using a coupled climate-chemical model of the troposphere, by calculating the impact of the predicted global warming due to increased emissions of carbon dioxide and other industrial gases on the biospheric sources of methane. Although we find this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH/sub 4/ concentration, a quantity which should additionally increase as a consequence of increasing anthropogenic emissions of CO and CH/sub 4/ itself. It would thus seem useful to carefully monitor future atmospheric CH/sub 4/ concentrations.

Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

Science.gov (United States)

Thorpe, Andrew K.; Frankenberg, Christian; Thompson, David R.; Duren, Riley M.; Aubrey, Andrew D.; Bue, Brian D.; Green, Robert O.; Gerilowski, Konstantin; Krings, Thomas; Borchardt, Jakob; Kort, Eric A.; Sweeney, Colm; Conley, Stephen; Roberts, Dar A.; Dennison, Philip E.

2017-10-01

At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS) method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

Directory of Open Access Journals (Sweden)

A. K. Thorpe

2017-10-01

Full Text Available At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

Assessing methane emission from dairy cows : modeling and experimental approaches on rumen microbial metabolism

NARCIS (Netherlands)

Lingen, Henk J.

2017-01-01

Methane (CH4) is a greenhouse gas (GHG) with a global warming potential of 28 CO2 equivalents. The livestock sector was estimated to emit 7.1 gigatonnes of CO2 equivalents, which is approximately 14.5% of total global anthropogenic GHG emissions. Enteric CH4 production is the main source of GHG

Trends and inter-annual variability of methane emissions derived from 1979-1993 global CTM simulations

Directory of Open Access Journals (Sweden)

F. Dentener

2003-01-01

Full Text Available The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistry-transport model. Our semi-inverse analysis uses the fifteen years (1979--1993 re-analysis of ECMWF meteorological data and annually varying emissions including photo-chemistry, in conjunction with observed CH4 concentration distributions and trends derived from the NOAA-CMDL surface stations. Dividing the world in four zonal regions (45--90 N, 0--45 N, 0--45 S, 45--90 S we find good agreement in each region between (top-down calculated emission trends from model simulations and (bottom-up estimated anthropogenic emission trends based on the EDGAR global anthropogenic emission database, which amounts for the period 1979--1993 2.7 Tg CH4 yr-1. Also the top-down determined total global methane emission compares well with the total of the bottom-up estimates. We use the difference between the bottom-up and top-down determined emission trends to calculate residual emissions. These residual emissions represent the inter-annual variability of the methane emissions. Simulations have been performed in which the year-to-year meteorology, the emissions of ozone precursor gases, and the stratospheric ozone column distribution are either varied, or kept constant. In studies of methane trends it is most important to include the trends and variability of the oxidant fields. The analyses reveals that the variability of the emissions is of the order of 8Tg CH4 yr-1, and likely related to wetland emissions and/or biomass burning.

Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions.

Science.gov (United States)

Miller, Benjamin L; Arntzen, Evan V; Goldman, Amy E; Richmond, Marshall C

2017-10-01

The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions

Science.gov (United States)

Miller, Benjamin L.; Arntzen, Evan V.; Goldman, Amy E.; Richmond, Marshall C.

2017-10-01

The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts Based on Metagenomic Gene Abundance.

Directory of Open Access Journals (Sweden)

Rainer Roehe

2016-02-01

Full Text Available Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e

Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues

Science.gov (United States)

Douglas, P. M. J.; Stolper, D. A.; Smith, D. A.; Walter Anthony, K. M.; Paull, C. K.; Dallimore, S.; Wik, M.; Crill, P. M.; Winterdahl, M.; Eiler, J. M.; Sessions, A. L.

2016-09-01

Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Δ18 values spanning a range of more than 5‰.

Sustainable application of reciprocating gas engines operating on coal mine methane

Energy Technology Data Exchange (ETDEWEB)

Lee, J.; Teo, T. [Caterpillar China Investment Co., Beijing (China); Tnay, C.H. [Westrac Inc., Beijing (China)

2008-07-01

According to the World Coal Institute, coal provides 25 per cent of worldwide primary energy needs and generates 40 per cent of the world's electricity. China produces the largest amount of hard coal. The anthropogenic release of methane (CH{sub 4}) into the environment is a byproduct of the coal mining process. The global warming potential of this methane continues to draw attention around the world. In particular, China's government has recognized the need for environmental responsibility in the pursuit of greater power production. The Kyoto Protocol requires developed countries to reduce their greenhouse gas emissions and targets must be met within a five-year time frame between 2008 and 2012. Sequestering coal mine methane (CMM) as an alternative fuel for reciprocating gas engine generator sets is a mature and proven technology for greenhouse gas mitigation. Prior to commissioning CMM-fueled power systems, the methane gas composition must be evaluated. An integrated systems approach can then be used to develop a CMM-fueled power project. This paper discussed the sustainable application of reciprocating gas engines operating on coal mine methane. It discussed the Kyoto Protocol, clean development mechanism, and CMM as compared to other fuel sources. It was concluded that there is considerable opportunity for growth in the Asia-Pacific region for electric power applications using CMM. 4 refs., 12 figs.

Methane hydrates in nature - Current knowledge and challenges

Science.gov (United States)

Collett, Timothy S.

2014-01-01

Recognizing the importance of methane hydrate research and the need for a coordinated effort, the United States Congress enacted the Methane Hydrate Research and Development Act of 2000. At the same time, the Ministry of International Trade and Industry in Japan launched a research program to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. India, China, the Republic of Korea, and other nations also have established large methane hydrate research and development programs. Government-funded scientific research drilling expeditions and production test studies have provided a wealth of information on the occurrence of methane hydrates in nature. Numerous studies have shown that the amount of gas stored as methane hydrates in the world may exceed the volume of known organic carbon sources. However, methane hydrates represent both a scientific and technical challenge, and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of methane hydrates in nature, (2) assessing the volume of natural gas stored within various methane hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural methane hydrates, (5) analyzing the methane hydrate role as a geohazard, (6) establishing the means to detect and characterize methane hydrate accumulations using geologic and geophysical data, and (7) establishing the thermodynamic phase equilibrium properties of methane hydrates as a function of temperature, pressure, and gas composition. The U.S. Department of Energy (DOE) and the Consortium for Ocean Leadership (COL) combined their efforts in 2012 to assess the contributions that scientific drilling has made and could continue to make to advance

Mapping urban pipeline leaks: Methane leaks across Boston

International Nuclear Information System (INIS)

Phillips, Nathan G.; Ackley, Robert; Crosson, Eric R.; Down, Adrian; Hutyra, Lucy R.; Brondfield, Max; Karr, Jonathan D.; Zhao Kaiguang; Jackson, Robert B.

2013-01-01

Natural gas is the largest source of anthropogenic emissions of methane (CH 4 ) in the United States. To assess pipeline emissions across a major city, we mapped CH 4 leaks across all 785 road miles in the city of Boston using a cavity-ring-down mobile CH 4 analyzer. We identified 3356 CH 4 leaks with concentrations exceeding up to 15 times the global background level. Separately, we measured δ 13 CH 4 isotopic signatures from a subset of these leaks. The δ 13 CH 4 signatures (mean = −42.8‰ ± 1.3‰ s.e.; n = 32) strongly indicate a fossil fuel source rather than a biogenic source for most of the leaks; natural gas sampled across the city had average δ 13 CH 4 values of −36.8‰ (±0.7‰ s.e., n = 10), whereas CH 4 collected from landfill sites, wetlands, and sewer systems had δ 13 CH 4 signatures ∼20‰ lighter (μ = −57.8‰, ±1.6‰ s.e., n = 8). Repairing leaky natural gas distribution systems will reduce greenhouse gas emissions, increase consumer health and safety, and save money. Highlights: ► We mapped 3356 methane leaks in Boston. ► Methane leaks in Boston carry an isotopic signature of pipeline natural gas. ► Replacing failing gas pipelines will provide safety, environmental, and economic benefits. - We identified 3356 methane leaks in Boston, with isotopic characteristics consistent with pipeline natural gas.

Performance Simulations for a Spaceborne Methane Lidar Mission

Science.gov (United States)

Kiemle, C.; Kawa, Stephan Randolph; Quatrevalet, Mathieu; Browell, Edward V.

2014-01-01

Future spaceborne lidar measurements of key anthropogenic greenhouse gases are expected to close current observational gaps particularly over remote, polar, and aerosol-contaminated regions, where actual in situ and passive remote sensing observation techniques have difficulties. For methane, a "Methane Remote Lidar Mission" was proposed by Deutsches Zentrum fuer Luft- und Raumfahrt and Centre National d'Etudes Spatiales in the frame of a German-French climate monitoring initiative. Simulations assess the performance of this mission with the help of Moderate Resolution Imaging Spectroradiometer and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations of the earth's surface albedo and atmospheric optical depth. These are key environmental parameters for integrated path differential absorption lidar which uses the surface backscatter to measure the total atmospheric methane column. Results showthat a lidar with an average optical power of 0.45W at 1.6 µm wavelength and a telescope diameter of 0.55 m, installed on a low Earth orbit platform(506 km), will measure methane columns at precisions of 1.2%, 1.7%, and 2.1% over land, water, and snow or ice surfaces, respectively, for monthly aggregated measurement samples within areas of 50 × 50 km2. Globally, the mean precision for the simulated year 2007 is 1.6%, with a standard deviation of 0.7%. At high latitudes, a lower reflectance due to snow and ice is compensated by denser measurements, owing to the orbital pattern. Over key methane source regions such as densely populated areas, boreal and tropical wetlands, or permafrost, our simulations show that the measurement precision will be between 1 and 2%.

Airborne Measurements of Atmospheric Methane Using Pulsed Laser Transmitters

Science.gov (United States)

Numata, Kenji; Riris, Haris; Wu, Stewart; Gonzalez, Brayler; Rodriguez, Michael; Hasselbrack, William; Fahey, Molly; Yu, Anthony; Stephen, Mark; Mao, Jianping;

Speciation of anthropogenic emissions of non-methane volatile organic compounds: a global gridded data set for 1970–2012

Directory of Open Access Journals (Sweden)

G. Huang

2017-06-01

Full Text Available Non-methane volatile organic compounds (NMVOCs include a large number of chemical species which differ significantly in their chemical characteristics and thus in their impacts on ozone and secondary organic aerosol formation. It is important that chemical transport models (CTMs simulate the chemical transformation of the different NMVOC species in the troposphere consistently. In most emission inventories, however, only total NMVOC emissions are reported, which need to be decomposed into classes to fit the requirements of CTMs. For instance, the Emissions Database for Global Atmospheric Research (EDGAR provides spatially resolved global anthropogenic emissions of total NMVOCs. In this study the EDGAR NMVOC inventory was revised and extended in time and in sectors. Moreover the new version of NMVOC emission data in the EDGAR database were disaggregated on a detailed sector resolution to individual species or species groups, thus enhancing the usability of the NMVOC emission data by the modelling community. Region- and source-specific speciation profiles of NMVOC species or species groups are compiled and mapped to EDGAR processes (detailed resolution of sectors, with corresponding quality codes specifying the quality of the mapping. Individual NMVOC species in different profiles are aggregated to 25 species groups, in line with the common classification of the Global Emissions Initiative (GEIA. Global annual grid maps with a resolution of 0.1°  ×  0.1° for the period 1970–2012 are produced by sector and species. Furthermore, trends in NMVOC composition are analysed, taking road transport and residential sources in Germany and the United Kingdom (UK as examples.

Methane emissions from oceans, coasts, and freshwater habitats: New perspectives and feedbacks on climate

Science.gov (United States)

Hamdan, Leila J.; Wickland, Kimberly P.

2016-01-01

Methane is a powerful greenhouse gas, and atmospheric concentrations have risen 2.5 times since the beginning of the Industrial age. While much of this increase is attributed to anthropogenic sources, natural sources, which contribute between 35% and 50% of global methane emissions, are thought to have a role in the atmospheric methane increase, in part due to human influences. Methane emissions from many natural sources are sensitive to climate, and positive feedbacks from climate change and cultural eutrophication may promote increased emissions to the atmosphere. These natural sources include aquatic environments such as wetlands, freshwater lakes, streams and rivers, and estuarine, coastal, and marine systems. Furthermore, there are significant marine sediment stores of methane in the form of clathrates that are vulnerable to mobilization and release to the atmosphere from climate feedbacks, and subsurface thermogenic gas which in exceptional cases may be released following accidents and disasters (North Sea blowout and Deepwater Horizon Spill respectively). Understanding of natural sources, key processes, and controls on emission is continually evolving as new measurement and modeling capabilities develop, and different sources and processes are revealed. This special issue of Limnology and Oceanography gathers together diverse studies on methane production, consumption, and emissions from freshwater, estuarine, and marine systems, and provides a broad view of the current science on methane dynamics of aquatic ecosystems. Here, we provide a general overview of aquatic methane sources, their contribution to the global methane budget, and key uncertainties. We then briefly summarize the contributions to and highlights of this special issue.

Robust IR Remote Sensing Technique of the Total Column of Trace Gases Including Carbon Dioxide and Methane

Science.gov (United States)

Georgieva, E. M.; Heaps, W. S.

2011-01-01

Progress on the development of a differential radiometer based upon the Fabry-Perot interferometer (FPI) for methane (CH4) and carbon dioxide (C02) detection in the atmosphere is presented. Methane measurements are becoming increasingly important as a component of NASA's programs to understand the global carbon cycle and quantifY the threat of global warming. Methane is the third most important greenhouse gas in the Earth's radiation budget (after water vapor and carbon dioxide) and the second most important anthropogenic contributor to global warming. The importance of global warming and air quality to society caused the National Research Council to recommend that NASA develop the following missions [1]: ASCENDS (Active Sensing of C02 Emissions over Nights, Days, and Seasons), GEOCAPE (Geostationary Coastal and Air Pollution Events), and GACM (Global Atmosphere Composition Mission). Though methane measurements are not specifically called out in these missions, ongoing environmental changes have raised the importance of understanding the methane budget. In the decadal survey is stated that "to close the carbon budget, we would also address methane, but the required technology is not obvious at this time. If appropriate and cost-effective methane technology becomes available, we strongly recommend adding a methane capability". In its 2007 report the International Panel on Climate Change identified methane as a key uncertainty in our understanding saying that the causes of recent changes in the growth rate of atmospheric CH4 are not well understood. What we do know is that methane arises from a number of natural sources including wet lands and the oceans plus man made sources from agriculture, as well as coal and petroleum production and distribution. It has recently been pointed out that large amount of methane are frozen in the permafrost of Canada and Siberia. There is a fear that melting of this permafrost driven by global warming may release large amounts of

Indian oil company joins efforts to reduce methane emissions

Science.gov (United States)

Kumar, Mohi

The Oil and Natural Gas Corp, Ltd. (ONGC), headquartered in Dehradun, India, has joined seven U.S. and Canadian oil and natural gas companies as a partner in a U.S. Environmental Protection Agency program to reduce greenhouse gas emissions. EPA's Natural Gas STAR International Program aims to reduce methane emissions from the oil and natural gas sector while delivering more gas to markets around the world. With this partnership, ONGC agrees to implement emissions reduction practices and to submit annual reports on progress achieved; EPA agrees to assist ONGC with training technicians in new cost-effective technologies that will help achieve target emissions. The Natural Gas STAR International Program is administered under the Methane to Markets Partnership, a group of 20 countries and 600 companies across the globe that since 2004 has volunteered to cut methane emissions. More information on EPA's agreement with ONGC can be found at http://www.epa.gov/gasstar/index.htm; information about the Methane to Markets Partnership can be found at http://www.methanetomarkets.org.

Shallow Aquifer Methane Gas Source Assessment

Science.gov (United States)

Coffin, R. B.; Murgulet, D.; Rose, P. S.; Hay, R.

2014-12-01

Shale gas can contribute significantly to the world's energy demand. Hydraulic fracturing (fracking) on horizontal drill lines developed over the last 15 years makes formerly inaccessible hydrocarbons economically available. From 2000 to 2035 shale gas is predicted to rise from 1% to 46% of the total natural gas for the US. A vast energy resource is available in the United States. While there is a strong financial advantage to the application of fracking there is emerging concern about environmental impacts to groundwater and air quality from improper shale fracking operations. Elevated methane (CH4) concentrations have been observed in drinking water throughout the United States where there is active horizontal drilling. Horizontal drilling and hydraulic-fracturing can increase CH4 transport to aquifers, soil and the vadose zone. Seepage can also result from casing failure in older wells. However, there is strong evidence that elevated CH4 concentrations can be associated with topographic and hydrogeologic features, rather than shale-gas extraction processes. Carbon isotope geochemistry can be applied to study CH4source(s) in shallow vadose zone and groundwater systems. A preliminary TAMU-CC isotope data set from samples taken at different locations in southern Texas shows a wide range of CH4 signatures suggesting multiple sources of methane and carbon dioxide. These data are interpreted to distinguish regions with methane contributions from deep-sourced horizontal drilling versus shallow system microbial production. Development of a thorough environmental assessment using light isotope analysis can provide understanding of shallow anthropogenic versus natural CH4sources and assist in identifying regions that require remedial actions.

Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region.

Science.gov (United States)

Frankenberg, C.

2016-12-01

Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit ˜ 2 kg/h to 5 kg/h through ˜ 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, natural seeps and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. We will summarize the campaign results and provide an overview of how airborne remote sensing can be used to detect and infer methane fluxes over widespread geographic areas and how new instrumentation could be used to perform similar observations from space.

Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover

NARCIS (Netherlands)

Kim, G.W.; Ho, A.; Kim, P.J.; Kim, Sang Yun

2016-01-01

The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to

Sources of atmospheric methane from coastal marine wetlands

International Nuclear Information System (INIS)

Harriss, R.C.; Sebacher, D.I.; Bartlett, K.B.; Bartlett, D.S.

1982-01-01

Biological methanogenesis in wetlands is believed to be one of the major sources of global tropospheric methane. The present paper reports measurements of methane distribution in the soils, sediments, water and vegetation of coastal marine wetlands. Measurements, carried out in the salt marshes Bay Tree Creek in Virginia and Panacea in northwest Florida, reveal methane concentrations in soils and sediments to vary with depth below the surface and with soil temperature. The fluxes of methane from marsh soils to the atmosphere at the soil-air interface are estimated to range from -0.00067 g CH 4 /sq m per day (methane sink) to 0.024 g CH 4 /sq m per day, with an average value of 0.0066 g CH 4 /sq m per day. Data also demonstrate the important role of tidal waters percolating through marsh soils in removing methane from the soils and releasing it to the atmosphere. The information obtained, together with previous studies, provides a framework for the design of a program based on in situ and remote sensing measurements to study the global methane cycle

Designing and implementing science-based methane policies

Science.gov (United States)

George, F.

2017-12-01

The phenomenal growth in shale gas production across the U.S. has significantly improved the energy security and economic prospects of the country. Natural gas is a "versatile" fuel that has application in every major end-use sector of the economy, both as a fuel and a feedstock. Natural gas has also played a significant role in reducing CO2 emissions from the power sector by displacing more carbon intensive fossil fuels. However, emissions of natural gas (predominantly methane) from the wellhead to the burner tip can erode this environmental benefit. Preserving the many benefits of America's natural gas resources requires smart, science-based policies to optimize the energy delivery efficiency of the natural gas supply chain and ensure that natural gas remains a key pillar in our transition to a low-carbon economy. Southwestern Energy (SWN) is the third largest natural gas producer in the United States. Over the last several years, SWN has participated in a number of scientific studies with regulatory agencies, academia and non-governmental entities that have led to over a dozen peer-reviewed papers on methane emissions from oil and gas operations. This presentation will review how our participation in these studies has informed our internal policies and procedures, as well as our external programs, including the ONE Future coalition (ONE Future). In particular, the presentation will highlight the impact of such studies on our Leak Detection and Repair (LDAR) program, designing new methane research and on the ONE Future initiatives - all with the focus of improving the delivery efficiency of oil and gas operations. Our experience supports continued research in the detection and mitigation of methane emissions, with emphasis on longer duration characterization of methane emissions from oil and gas facilities and further development of cost-effective methane detection and mitigation techniques. We conclude from our scientific and operational experiences that a

Urban sources and emissions of nitrous oxide and methane in southern California, USA

Science.gov (United States)

Townsend-Small, A.; Pataki, D.; Tyler, S. C.; Czimczik, C. I.; Xu, X.; Christensen, L. E.

2012-12-01

Anthropogenic activities have resulted in increasing levels of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. While global and regional emissions sources of carbon dioxide are relatively well understood, methane and nitrous oxide are less constrained, particularly at regional scales. Here we present the results of an investigation of sources and emissions of methane and nitrous oxide in Los Angeles, California, USA, one of Earth's largest urban areas. The original goal of the project was to determine whether isotopes are useful tracers of agricultural versus urban nitrous oxide and methane sources. For methane, we found that stable isotopes (carbon-13 and deuterium) and radiocarbon are good tracers of biogenic versus fossil fuel sources. High altitude observations of methane concentration, measured continuously using tunable laser spectroscopy, and isotope ratios, measured on discrete flask samples using mass spectrometry, indicate that the predominant methane source in Los Angeles is from fossil fuels, likely from "fugitive" emissions from geologic formations, natural gas pipelines, oil refining, or power plants. We also measured nitrous oxide emissions and isotope ratios from urban (landscaping and wastewater treatment) and agricultural sources (corn and vegetable fields). There was no difference in nitrous oxide isotope ratios between the different types of sources, although stable isotopes did differ between nitrous oxide produced in oxic and anoxic wastewater treatment tanks. Our nitrous oxide flux data indicate that landscaped turfgrass emits nitrous oxide at rates equivalent to agricultural systems, indicating that ornamental soils should not be disregarded in regional nitrous oxide budgets. However, we also showed that wastewater treatment is a much greater source of nitrous oxide than soils regionally. This work shows that global nitrous oxide and methane budgets are not easily downscaled to regional, urban settings, which has

Methane emissions form terrestrial plants

Energy Technology Data Exchange (ETDEWEB)

Bergamaschi, P.; Dentener, F.; Grassi, G.; Leip, A.; Somogyi, Z.; Federici, S.; Seufert, G.; Raes, F. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

2006-07-01

In a recent issue of Nature Keppler et al. (2006) report the discovery that terrestrial plants emit CH4 under aerobic conditions. Until now it was thought that bacterial decomposition of plant material under anaerobic conditions, such as in wetlands and water flooded rice paddies, is the main process leading to emissions from terrestrial ecosystems. In a first attempt to upscale these measurements, the authors estimate that global total emissions may be 149 Tg CH4/yr (62-236 Tg CH4/yr), with the main contribution estimated from tropical forests and grasslands (107 Tg CH4/yr with a range of 46-169 Tg CH4/yr). If confirmed, this new source of emission would constitute a significant fraction of the total global methane sources (estimated 500-600 Tg CH4/yr for present day total natural and anthropogenic sources) and have important implications for the global CH4 budget. To accommodate it within the present budget some sources would need to be re-assessed downwards and/or some sinks re-assessed upwards. Furthermore, also considering that methane is a {approx}23 times more powerful greenhouse gas than CO2, the possible feedbacks of these hitherto unknown CH4 emissions on global warming and their impacts on greenhouse gases (GHG) mitigation strategies need to be carefully evaluated. The merit of the paper is without doubt related to the remarkable discovery of a new process of methane emissions active under aerobic conditions. However, we think that the applied approach of scaling up emissions from the leaf level to global totals by using only few measured data (mainly from herbaceous species) and the Net Primary Productivity of the main biomes is scientifically questionable and tends to overestimate considerably the global estimates, especially for forest biomes. Furthermore, some significant constraints on the upper limit of the global natural CH4 emissions arise from the pre-industrial CH4 budget. Pre-industrial atmospheric CH4 mixing ratios have been measured

Global distribution of methane emissions, emission trends, and OH trends inferred from an inversion of GOSAT data for 2010-2015

Science.gov (United States)

Maasakkers, J. D.; Jacob, D.; Payer Sulprizio, M.; Hersher, M.; Scarpelli, T.; Turner, A. J.; Sheng, J.; Bloom, A. A.; Bowman, K. W.; Parker, R.

2017-12-01

We present a global inversion of methane sources and sinks using GOSAT satellite data from 2010 up to 2015. The inversion optimizes emissions and their trends at 4° × 5° resolution as well as the interannual variability of global OH concentrations. It uses an analytical approach that quantifies the information content from the GOSAT observations and provides full error characterization. We show how the analytical approach can be applied in log-space, ensuring the positivity of the posterior. The inversion starts from state-of-science a priori emission inventories including the Gridded EPA inventory for US anthropogenic emissions, detailed oil and gas emissions for Canada and Mexico, EDGAR v4.3.2 for anthropogenic emissions in other countries, the WetCHARTs product for wetlands, and our own estimates for geological seeps. Inversion results show lower emissions over Western Europe and China than predicted by EDGAR v4.3.2 but higher emissions over Japan. In contrast to previous inversions that used incorrect patterns in a priori emissions, we find that the EPA inventory does not underestimate US anthropogenic emissions. Results for trends show increasing emissions in the tropics combined with decreasing emissions in Europe, and a decline in OH concentrations contributing to the global methane trend.

How to reduce risk of climate change: Domestic hot water production methanization and programmed timing of heaters

International Nuclear Information System (INIS)

Silvestrini, G.

1992-01-01

This paper first identifies a significant and deleterious trend, in terms of poor energy efficiency and high carbon dioxide emissions, towards the increased use of electric water heaters for sanitary hot water production in single family units. It then points out how the use of wall mounted methane fired boilers can result in overall energy savings (overall electric power consumption for domestic hot water production is estimated to represent one- quarter of Italy's total domestic power demand), as well as air pollution abatement. The feasibility of other methods of energy conservation and pollution abatement in domestic water heating are also examined. These include the use of solar hot water heaters, computerized timers which allow users to program the operation of their heating plants, and the adoption by residential communities of methane fuelled district heating plants

Use of the HadGEM2 climate-chemistry model to investigate interannual variability in methane sources

Science.gov (United States)

Hayman, Garry; O'Connor, Fiona; Clark, Douglas; Huntingford, Chris; Gedney, Nicola

2013-04-01

The global mean atmospheric concentration of methane (CH4) has more than doubled during the industrial era [1] and now constitutes ? 20% of the anthropogenic climate forcing by greenhouse gases [2]. The globally-averaged CH4 growth rate, derived from surface measurements, has fallen significantly from a high of 16 ppb yr-1 in the late 1970s/early 1980s and was close to zero between 1999 and 2006 [1]. This overall period of declining or low growth was however interspersed with years of positive growth-rate anomalies (e.g., in 1991-1992, 1998-1999 and 2002-2003). Since 2007, renewed growth has been evident [1, 3], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics in 2008. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [1, 4]. In this paper, we report results from runs of the HadGEM2 climate-chemistry model [5] using year- and month-specific emission datasets. The HadGEM2 model includes the comprehensive atmospheric chemistry and aerosol package, the UK Chemistry Aerosol community model (UKCA, http://www.ukca.ac.uk/wiki/index.php). The Standard Tropospheric Chemistry scheme was selected for this work. This chemistry scheme simulates the Ox, HOx and NOx chemical cycles and the oxidation of CO, methane, ethane and propane. Year- and month-specific emission datasets were generated for the period from 1997 to 2009 for the emitted species in the chemistry scheme (CH4, CO, NOx, HCHO, C2H6, C3H8, CH3CHO, CH3CHOCH3). The approach adopted varied depending on the source sector: Anthropogenic: The emissions from anthropogenic sources were based on decadal-averaged emission inventories compiled by [6] for the Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP). These were then used to derive year-specific emission datasets by scaling the

Impact of Methane Leak Detection and Repair Programs: Determining Pre- and Post-Survey Emissions Profiles

Science.gov (United States)

Roda-Stuart, D. J.; Ravikumar, A. P.; Brandt, A. R.

2017-12-01

Upstream production sites contribute 66 percent of methane emissions from natural gas systems [1]. Being a major greenhouse gas, many states and national governments are developing policies to reduce methane emissions. Recent policies to address this issue have focused on periodic leak detection and repair (LDAR) surveys at oil and gas facilities [2]. Development of effective LDAR surveys is complicated by two things. First, available empirical data makes it difficult to say anything definitive about which facilities or equipment are most prone to leakage. Second, there has been little research done on post-LDAR emissions profiles and the time evolution of leaks, two measures that would influence survey effectiveness and cost. In this work, we present data from LDAR operations conducted at upstream facilities of a Canadian natural gas producer. Surveys were done by an outside contractor using a FLIR optical gas imaging camera. Twenty-two well pads, five processing plants, and three compressor stations were surveyed, of which four, two, and one, respectively, were revisited. We examine the persistence of leaks over time periods ranging from 6 months to 15 months following the initial LDAR survey. Developing pre- and post-survey emission factors and distributions can help inform survey schedules and help update and monitor mitigation targets. Furthermore, we analyze the effect of weather conditions, survey frequency, and operational characteristics of equipment on the effectiveness of the LDAR program. For instance, we find that a survey done at the commissioning of a gas processing plant yields both safety and emissions reduction benefits. Using leak frequency distributions, we identify components and equipment that require more frequent and targeted surveying. Insights from this study can assist businesses and policy makers develop methane mitigation policies aimed at maximizing the marginal benefits of LDAR programs. [1] Inventory of U.S. Greenhouse Gas Emissions

The distribution of methane in groundwater in Alberta (Canada) and associated aqueous geochemistry conditions

Science.gov (United States)

Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Millot, Romain; Kloppmann, Wolfram

2016-04-01

Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish: (a) natural in-situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. We have conducted a NSERC-ANR co-funded baseline study investigating the occurrence of methane in shallow groundwater of Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. Our objective was to assess the occurrence and sources of methane in shallow groundwaters and to also characterize the hydrochemical environment in which the methane was formed or transformed through redox processes. Ultimately our aim was to determine whether methane was formed in-situ or whether it migrated from deeper formations into shallow aquifers. Combining hydrochemical and dissolved and free geochemical gas data from 372 groundwater samples obtained from 186 monitoring wells of the provincial groundwater observation well network (GOWN) in Alberta, it was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of dissolved biogenic methane (> 0.01 mM or > 0.2 mg/L), characterized by δ13CCH4 values deep thermogenic gas that had migrated in significant amounts into shallow aquifers either naturally or via anthropogenically induced pathways. This study shows that the combined interpretation of aqueous geochemistry data in concert with the chemical and isotopic composition of dissolved and

A comparison of PCA and PMF models for source identification of fugitive methane emissions

Science.gov (United States)

Assan, Sabina; Baudic, Alexia; Bsaibes, Sandy; Gros, Valerie; Ciais, Philippe; Staufer, Johannes; Robinson, Rod; Vogel, Felix

2017-04-01

Methane (CH_4) is a greenhouse gas with a global warming potential 28-32 times that of carbon dioxide (CO_2) on a 100 year period, and even greater on shorter timescales [Etminan, et al., 2016, Allen, 2014]. Thus, despite its relatively short life time and smaller emission quantities compared to CO_2, CH4 emissions contribute to approximately 20{%} of today's anthropogenic greenhouse gas warming [Kirschke et al., 2013]. Major anthropogenic sources include livestock (enteric fermentation), oil and gas production and distribution, landfills, and wastewater emissions [EPA, 2011]. Especially in densely populated areas multiple CH4 sources can be found in close vicinity. Thus, when measuring CH4 emissions at local scales it is necessary to distinguish between different CH4 source categories to effectively quantify the contribution of each sector and aid the implementation of greenhouse gas reduction strategies. To this end, source apportionment models can be used to aid the interpretation of spatial and temporal patterns in order to identify and characterise emission sources. The focus of this study is to evaluate two common linear receptor models, namely Principle Component Analysis (PCA) and Positive Matrix Factorisation (PMF) for CH4 source apportionment. The statistical models I will present combine continuous in-situ CH4 , C_2H_6, δ^1^3CH4 measured using a Cavity Ring Down Spectroscopy (CRDS) instrument [Assan et al. 2016] with volatile organic compound (VOC) observations performed using Gas Chromatography (GC) in order to explain the underlying variance of the data. The strengths and weaknesses of both models are identified for data collected in multi-source environments in the vicinity of four different types of sites; an agricultural farm with cattle, a natural gas compressor station, a wastewater treatment plant, and a pari-urban location in the Ile de France region impacted by various sources. To conclude, receptor model results to separate statistically the

Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

Science.gov (United States)

Rivard, Christine; Bordeleau, Geneviève; Lavoie, Denis; Lefebvre, René; Malet, Xavier

2018-03-01

Dissolved methane concentrations in shallow groundwater are known to vary both spatially and temporally. The extent of these variations is poorly documented although this knowledge is critical for distinguishing natural fluctuations from anthropogenic impacts stemming from oil and gas activities. This issue was addressed as part of a groundwater research project aiming to assess the risk of shale gas development for groundwater quality over a 500-km2 area in the St. Lawrence Lowlands (Quebec, Canada). A specific study was carried out to define the natural variability of methane concentrations and carbon and hydrogen isotope ratios in groundwater, as dissolved methane is naturally ubiquitous in aquifers of this area. Monitoring was carried out over a period of up to 2.5 years in seven monitoring wells. Results showed that for a given well, using the same sampling depth and technique, methane concentrations can vary over time from 2.5 to 6 times relative to the lowest recorded value. Methane isotopic composition, which is a useful tool to distinguish gas origin, was found to be stable for most wells, but varied significantly over time in the two wells where methane concentrations are the lowest. The use of concentration ratios, as well as isotopic composition of methane and dissolved inorganic carbon (DIC), helped unravel the processes responsible for these variations. This study indicates that both methane concentrations and isotopic composition, as well as DIC isotopes, should be regularly monitored over at least 1 year to establish their potential natural variations prior to hydrocarbon development.

The impact of a 50% reduction of solid waste disposal in Canada on methane emissions from landfills in 2000

International Nuclear Information System (INIS)

Patenaude, L.M.F.; Owen, G.T.; Barclay, J.A.

1993-01-01

Canada's Green Plan established a goal of 50% reduction in municipal solid waste (MSW) disposal between 1988 and the year 2000. Canada has also committed to stabilizing greenhouse gas emissions at 1990 levels by 2000. MSW landfills are targeted since they account for a significant portion of anthropogenic methane emissions. Current composition and quantities of MSW were estimated. Using five scenarios for achieving a 50% reduction of waste disposed, the quantities and composition of waste managed were estimated through to the year 2000. A first-order decay model was used to estimate methane emissions from landfills of each scenario by varying the methane generation potential (L o ) based on the amount of biodegradable carbon in the MSW stream. Despite the overall reduction in waste, methane emissions are still projected on increase between 1990 and 2000 for scenarios with 25 to 45% of waste going to landfill in 2000. The estimated increases in methane emissions range from 2% for the high composting scenario to 16% for the high landfill scenario. In general, emissions peak during the 1990's and are decreasing by 2000. The projected increase in emissions is due to the 65--75% contribution of MSW landfilled before 1990. In conclusion, a significant reduction in methane emissions from landfills by 2000 will require methane recovery systems in addition to MSW reduction initiatives

MethaneSat: Detecting Methane Emissions in the Barnett Shale Region

Science.gov (United States)

Propp, A. M.; Benmergui, J. S.; Turner, A. J.; Wofsy, S. C.

2017-12-01

In this study, we investigate the new information that will be provided by MethaneSat, a proposed satellite that will measure the total column dry-air mole fraction of methane at 1x1 km or 2x2 km spatial resolution with 0.1-0.2% random error. We run an atmospheric model to simulate MethaneSat's ability to characterize methane emissions from the Barnett Shale, a natural gas province in Texas. For comparison, we perform observation system simulation experiments (OSSEs) for MethaneSat, the National Oceanic and Atmospheric administration (NOAA) surface and aircraft network, and Greenhouse Gases Observing Satellite (GOSAT). The results demonstrate the added benefit that MethaneSat would provide in our efforts to monitor and report methane emissions. We find that MethaneSat successfully quantifies total methane emissions in the region, as well as their spatial distribution and steep gradients. Under the same test conditions, both the NOAA network and GOSAT fail to capture this information. Furthermore, we find that the results for MethaneSat depend far less on the prior emission estimate than do those for the other observing systems, demonstrating the benefit of high sampling density. The results suggest that MethaneSat would be an incredibly useful tool for obtaining detailed methane emission information from oil and gas provinces around the world.

Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

Energy Technology Data Exchange (ETDEWEB)

Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

2012-03-29

The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

Estimation of Methane Emissions in the Los Angeles Basin using CLARS-FTS Observations

Science.gov (United States)

Sander, S.; Zeng, Z. C.; Pongetti, T.; Duren, R. M.; Shia, R. L.; Yung, Y. L.; He, L.; Gurney, K. R.

2017-12-01

The Los Angeles Basin (LA Basin), covering almost 10,743 square miles, is home to over 16.8 million people - about half the population of the state of California. It is also the second most populated urban area in the United States and one of the major source of anthropogenic greenhouse gases. Using FTIR observations from the California Laboratory for Atmospheric Remote Sensing (CLARS) located on Mount Wilson at an altitude of 1673m, we measure the reflected near infrared sunlight from 33 surface targets in the Los Angeles megacity including the direct solar beam which gives the free tropospheric background. We then retrieve the excess slant column abundances of important trace gases such as carbon dioxide (CO2) and methane (CH4) in the LA basin. Using atmospheric tracer - tracer correlations for CH4 and CO2 to eliminate the effect of aerosol scattering in the retrieval, we infer methane emissions based on the ratio of XCH4 excess to XCO2 excess. Significant variability is observed in the spatial distributions of excess CH4. Methane emissions in the LA basin show consistent peaks in late summer and winter during the period from Sep 2011 to the present. The strong correlation between natural gas usage data and derived CLARS methane emissions (r2 = 0.5) implies that natural gas leakage during transmission and/or consumption accounts for a significant fraction of the inferred seasonal variability of methane emissions in the LA basin. We will report updated annual trends in CH4 emissions from 2011 to the present. Copyright 2017. All rights reserved.

Methane Recycling During Burial of Methane Hydrate-Bearing Sediments

Science.gov (United States)

You, K.; Flemings, P. B.

2017-12-01

We quantitatively investigate the integral processes of methane hydrate formation from local microbial methane generation, burial of methane hydrate with sedimentation, and methane recycling at the base of the hydrate stability zone (BHSZ) with a multiphase multicomponent numerical model. Methane recycling happens in cycles, and there is not a steady state. Each cycle starts with free gas accumulation from hydrate dissociation below the BHSZ. This free gas flows upward under buoyancy, elevates the hydrate saturation and capillary entry pressure at the BHSZ, and this prevents more free gas flowing in. Later as this layer with elevated hydrate saturation is buried and dissociated, the large amount of free gas newly released and accumulated below rapidly intrudes into the hydrate stability zone, drives rapid hydrate formation and creates three-phase (gas, liquid and hydrate) equilibrium above the BHSZ. The gas front retreats to below the BHSZ until all the free gas is depleted. The shallowest depth that the free gas reaches in one cycle moves toward seafloor as more and more methane is accumulated to the BHSZ with time. More methane is stored above the BHSZ in the form of concentrated hydrate in sediments with relatively uniform pore throat, and/or with greater compressibility. It is more difficult to initiate methane recycling in passive continental margins where the sedimentation rate is low, and in sediments with low organic matter content and/or methanogenesis reaction rate. The presence of a permeable layer can store methane for significant periods of time without recycling. In a 2D system where the seafloor dips rapidly, the updip gas flow along the BHSZ transports more methane toward topographic highs where methane gas and elevated hydrate saturation intrude deeper into the hydrate stability zone within one cycle. This could lead to intermittent gas venting at seafloor at the topographic highs. This study provides insights on many phenomenon associated with

The Global Search for Abiogenic GHGs, via Methane Isotopes and Ethane

Science.gov (United States)

Malina, Edward; Muller, Jan-Peter; Walton, David; Potts, Dale

2015-04-01

The importance of Methane as an anthropogenic Green House Gas (GHG) is well recognized in the scientific community, and is second only to Carbon Dioxide in terms of influence on the Earth's radiation budget (Parker, et al, 2011) suggesting that the ability to apportion the source of the methane (whether it is biogenic, abiogenic or thermogenic) has never been more important. It has been proposed (Etiope, 2009) that it may be possible to distinguish between a biogenic methane source (e.g. bacteria fermentation) and an abiogenic source (e.g. gas seepage or fugitive emissions) via the retrieval of the abundances of methane isotopes (12CH4 and 13CH4) and through the ratio of ethane (C2H6) to methane (CH4) concentrations. Using ultra fine spectroscopy (simulations, we show that it is possible to distinguish between methane isotopes using the FTS based instruments on ACE and GOSAT, and retrieve the abundances in the Short Wave Infra-red (SWIR) at 1.65μm, 2.3μm, 3.3μm and Thermal IR, 7.8μm wavebands for methane, and the 3.3μm and 7μm wavebands for ethane. Initially we use the spectral line database HITRAN to determine the most appropriate spectral waveband to retrieve methane isotopes (and ethane) with minimal water vapour, CO2 and NO2 impact. Following this, we have evaluated the detectability of these trace gases using the more sophisticated Radiative Transfer Models (RTMs) SCIATRAN, the Oxford RFM and MODTRAN 5 in the SWIR, in order to determine the barriers to retrieving methane isotopes in both ACE (limb profile) and GOSAT (nadir measurements) instruments, including a preliminary investigation into the effects of clouds, aerosols, surface reflectance on the retrieval of methane isotopes. The aim of these RTM simulations is to further narrow down the spectral regions (originally identified in the HITRAN assessment) where methane isotopes can/may be retrieved from orbit. The key outputs from the RTM study are absorption and radiance data, which allow us to

Baseline Geochemistry of Natural Occurring Methane and Saline Groundwater in an Area of Unconventional Shale Gas Development Through Time

Science.gov (United States)

Harkness, J.; Darrah, T.; Warner, N. R.; Whyte, C. J.; Moore, M. T.; Millot, R.; Kloppmann, W.; Jackson, R. B.; Vengosh, A.

2017-12-01

Naturally occurring methane is nearly ubiquitous in most sedimentary basins and delineating the effects of anthropogenic contamination sources from geogenic sources is a major challenge for evaluating the impact of unconventional shale gas development on water quality. This study employs a broadly integrated study of various geochemical techniques to investigate the geochemical variations of groundwater and surface water before, during, and after hydraulic fracturing.This approache combines inorganic geochemistry (major cations and anions), stable isotopes of select inorganic constituents including strontium (87Sr/86Sr), boron (δ11B), lithium (δ7Li), and carbon (δ13C-DIC), select hydrocarbon molecular (methane, ethane, propane, butane, and pentane) and isotopic tracers (δ13C-CH4, δ13C-C2H6), tritium (3H), and noble gas elemental and isotopic composition (He, Ne, Ar) to apportion natural and anthropogenic sources of natural gas and salt contaminants both before and after drilling. Methane above 1 ccSTP/L in groundwater samples awas strongly associated with elevated salinity (chloride >50 mg/L).The geochemical and isotopic analysis indicate saline groundwater originated via naturally occurring processes, presumably from the migration of deeper methane-rich brines that have interacted extensively with coal lithologies. The chemistry and gas compostion of both saline and fresh groundwater wells did not change following the installation of nearby shale-gas wells.The results of this study emphasize the value of baseline characterization of water quality in areas of fossil fuel exploration. Overall this study presents a comprehensive geochemical framework that can be used as a template for assessing the sources of elevated hydrocarbons and salts to water resources in areas potentially impacted by oil and gas development.

Measuring Methane from Cars, Ships, Airplanes, Helicopters and Drones Using High-Speed Open-Path Technology

Science.gov (United States)

Burba, George; Anderson, Tyler; Biraud, Sebastien; Caulton, Dana; von Fischer, Joe; Gioli, Beniamino; Hanson, Chad; Ham, Jay; Kohnert, Katrin; Larmanou, Eric; Levy, Peter; Polidori, Andrea; Pikelnaya, Olga; Sachs, Torsten; Serafimovich, Andrei; Zaldei, Alessandro; Zondlo, Mark; Zulueta, Rommel

2017-04-01

Methane plays a critical role in the radiation balance, chemistry of the atmosphere, and air quality. The major anthropogenic sources of methane include oil and gas development sites, natural gas distribution networks, landfill emissions, and agricultural production. The majority of oil and gas and urban methane emission occurs via variable-rate point sources or diffused spots in topographically challenging terrains (e.g., street tunnels, elevated locations at water treatment plants, vents, etc.). Locating and measuring such methane emissions is challenging when using traditional micrometeorological techniques, and requires development of novel approaches. Landfill methane emissions traditionally assessed at monthly or longer time intervals are subject to large uncertainties because of the snapshot nature of the measurements and the barometric pumping phenomenon. The majority of agricultural and natural methane production occurs in areas with little infrastructure or easily available grid power (e.g., rice fields, arctic and boreal wetlands, tropical mangroves, etc.). A lightweight, high-speed, high-resolution, open-path technology was recently developed for eddy covariance measurements of methane flux, with power consumption 30-150 times below other available technologies. It was designed to run on solar panels or a small generator and be placed in the middle of the methane-producing ecosystem without a need for grid power. Lately, this instrumentation has been utilized increasingly more frequently outside of the traditional use on stationary flux towers. These novel approaches include measurements from various moving platforms, such as cars, aircraft, and ships. Projects included mapping of concentrations and vertical profiles, leak detection and quantification, mobile emission detection from natural gas-powered cars, soil methane flux surveys, etc. This presentation will describe the latest state of the key projects utilizing the novel lightweight low-power high

High-Resolution Mapping of Anthropogenic Heat in China from 1992 to 2010

Directory of Open Access Journals (Sweden)

Wangming Yang

2014-04-01

Full Text Available Anthropogenic heat generated by human activity contributes to urban and regional climate warming. Due to the resolution and accuracy of existing anthropogenic heat data, it is difficult to analyze and simulate the corresponding effects. This study exploited a new method to estimate high spatial and temporal resolutions of anthropogenic heat based on long-term data of energy consumption and the US Air Force Defense Meteorological Satellite Program-Operational Linescan System (DMSP-OLS data from 1992 to 2010 across China. Our results showed that, throughout the entire study period, there are apparent increasing trends in anthropogenic heat in three major metropoli, i.e., the Beijing-Tianjin region, the Yangzi River delta and the Pearl River delta. The annual mean anthropogenic heat fluxes for Beijing, Shanghai and Guangzhou in 2010 were 17 Wm−2, 19 and 7.8 Wm−2, respectively. Comparisons with previous studies indicate that DMSP-OLS data could provide a better spatial proxy for estimating anthropogenic heat than population density and our analysis shows better performance at large scales for estimation of anthropogenic heat.

Climate Change Policy and the Adoption of Methane Digesters on Livestock Operations

OpenAIRE

Key, Nigel D.; Sneeringer, Stacy E.

2011-01-01

Methane digesters—biogas recovery systems that use methane from manure to generate electricity—have not been widely adopted in the United States because costs have exceeded benefits to operators. Burning methane in a digester reduces greenhouse gas emissions from manure management. A policy or program that pays producers for these emission reductions—through a carbon offset market or directly with payments—could increase the number of livestock producers who would profit from adopting a metha...

Methane emissions from the natural gas industry

International Nuclear Information System (INIS)

Harrison, M.R.; Cowgill, R.M.; Campbell, L.M.; Lott, R.A.

1993-01-01

The U.S. EPA and the United Nation's Intergovernmental Panel on Climate Change (IPCC) have suggested that global warming could be reduced if more energy was generated using natural gas rather than fuels such as coal. An increased use of natural gas instead of coal would decrease global warming since methane emits less carbon dioxide (CO 2 ) than any fossil fuel. However, methane is a more potent as a greenhouse gas than CO 2 , and leakage from the gas system could reduce or eliminate the inherent advantage of natural gas. For this reason, methane emissions must be quantified before a national policy on preferred fuels is developed. Therefore, GRI and EPA have developed this confunded program to quantify methane emissions from the U.S. gas industry. This paper presents, for general industry review, the approach and methodology that the project is using to determine the emissions. The study will measure or calculate all gas industry methane emissions - from production at the wellhead, through the system, to the customer's meter. When these data are combined with data from other studies, a definitive comparison of the relative environmental impact of using methane versus other fuels will be possible. The study will also provide data that can be used by the industry to identify cost-effective mitigation techniques to reduce losses. The methane emissions project is being conducted in three phases: the first two phases have identified and ranked all known potential methane-emitting sources and established methods for measuring, calculating, and extrapolating emissions from those sources. The third phase, which is currently in progress, will gather sufficient data to achieve the accuracy goal. This paper briefly summarizes the methodology being used for the completion of the third phase

Anthropogenic radionuclides in the environment

Energy Technology Data Exchange (ETDEWEB)

Hu, Q; Weng, J; Wang, J

2007-11-15

Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

Potential Cost-Effective Opportunities for Methane Emission Abatement

Energy Technology Data Exchange (ETDEWEB)

Warner, Ethan [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Steinberg, Daniel [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Hodson, Elke [U.S. Department of Energy, Washington, DC (United States); Heath, Garvin [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States)

2015-08-01

The energy sector was responsible for approximately 84% of carbon dioxide equivalent (CO₂e) greenhouse gas (GHG) emissions in the U.S. in 2012 (EPA 2014a). Methane is the second most important GHG, contributing 9% of total U.S. CO₂e emissions. A large portion of those methane emissions result from energy production and use; the natural gas, coal, and oil industries produce approximately 39% of anthropogenic methane emissions in the U.S. As a result, fossil-fuel systems have been consistently identified as high priority sectors to contribute to U.S. GHG reduction goals (White House 2015). Only two studies have recently attempted to quantify the abatement potential and cost associated with the breadth of opportunities to reduce GHG emissions within natural gas, oil, and coal supply chains in the United States, namely the U.S. Environmental Protection Agency (EPA) (2013a) and ICF (2014). EPA, in its 2013 analysis, estimated the marginal cost of abatement for non-CO₂ GHG emissions from the natural gas, oil, and coal supply chains for multiple regions globally, including the United States. Building on this work, ICF International (ICF) (2014) provided an update and re-analysis of the potential opportunities in U.S. natural gas and oil systems. In this report we synthesize these previously published estimates as well as incorporate additional data provided by ICF to provide a comprehensive national analysis of methane abatement opportunities and their associated costs across the natural gas, oil, and coal supply chains. Results are presented as a suite of marginal abatement cost curves (MACCs), which depict the total potential and cost of reducing emissions through different abatement measures. We report results by sector (natural gas, oil, and coal) and by supply chain segment - production, gathering and boosting, processing, transmission and storage, or distribution - to facilitate identification of which sectors and supply chain

Light-Dependent Aerobic Methane Oxidation Reduces Methane Emissions from Seasonally Stratified Lakes

Science.gov (United States)

Oswald, Kirsten; Milucka, Jana; Brand, Andreas; Littmann, Sten; Wehrli, Bernhard; Kuypers, Marcel M. M.; Schubert, Carsten J.

2015-01-01

Lakes are a natural source of methane to the atmosphere and contribute significantly to total emissions compared to the oceans. Controls on methane emissions from lake surfaces, particularly biotic processes within anoxic hypolimnia, are only partially understood. Here we investigated biological methane oxidation in the water column of the seasonally stratified Lake Rotsee. A zone of methane oxidation extending from the oxic/anoxic interface into anoxic waters was identified by chemical profiling of oxygen, methane and δ13C of methane. Incubation experiments with 13C-methane yielded highest oxidation rates within the oxycline, and comparable rates were measured in anoxic waters. Despite predominantly anoxic conditions within the zone of methane oxidation, known groups of anaerobic methanotrophic archaea were conspicuously absent. Instead, aerobic gammaproteobacterial methanotrophs were identified as the active methane oxidizers. In addition, continuous oxidation and maximum rates always occurred under light conditions. These findings, along with the detection of chlorophyll a, suggest that aerobic methane oxidation is tightly coupled to light-dependent photosynthetic oxygen production both at the oxycline and in the anoxic bottom layer. It is likely that this interaction between oxygenic phototrophs and aerobic methanotrophs represents a widespread mechanism by which methane is oxidized in lake water, thus diminishing its release into the atmosphere. PMID:26193458

Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

Science.gov (United States)

Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

2013-04-01

Urban activities generate solid and liquid waste, and the handling and aftercare of the waste results in the emission of various compounds into the surrounding environment. Some of these compounds are emitted as gasses into the atmosphere, including methane and nitrous oxide. Methane and nitrous oxide are strong greenhouse gases and are considered to have 25 and 298 times the greenhouse gas potential of carbon dioxide on a hundred years term (Solomon et al. 2007). Global observations of both gasses have shown increasing concentrations that significantly contribute to the greenhouse gas effect. Methane and nitrous oxide are emitted from both natural and anthropogenic sources and inventories of source specific fugitive emissions from the anthropogenic sources of methane and nitrous oxide of are often estimated on the basis of modeling and mass balance. Though these methods are well-developed, actual measurements for quantification of the emissions is a very useful tool for verifying the modeling and mass balance as well as for validation initiatives done for lowering the emissions of methane and nitrous oxide. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001, Scheutz et al. 2011), where the exact location of the source is located and a tracer gas is released at this source location at a known flow. The ratio of downwind concentrations of the tracer gas and the methane and nitrous oxide gives the emissions rates of the greenhouse gases. This tracer dilution method can be performed using both stationary and mobile measurements and in both cases, real-time measurements of both tracer and quantified gas are required, placing high demands on the analytical detection method. To perform the methane and nitrous oxide measurements, two robust instruments capable of real-time measurements were used, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. One instrument measured the methane and

Management practices and controls on methane emissions from sub-tropical wetlands

Science.gov (United States)

DeLucia, Nicholas; Casa-Nova Gomez, Nuri; Bernacchi, Carl

2015-04-01

It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on any combination of climate conditions, natural and anthropogenic disturbances, or ecosystem perturbations. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are the main source for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. CH4 is one of the most damaging green house gases with current emission estimates ranging from 55 to 231 Tg CH4 yr-1. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04"N, 81o21'8.56"W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified

Methanation. Utilization of CO{sub 2} instead of final storage; Methanisierung. CO{sub 2} nutzen statt endlagern

Energy Technology Data Exchange (ETDEWEB)

Schmid, Juergen [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany); Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveraenderungen (WBGU), Potsdam (Germany); Guenther, Matthias [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)

2013-03-15

The capture and permanent storage of carbon dioxide (CCS) is a possibility to limit the anthropogenic climate change. However, the financial and technical challenges for CCS on a large scale are significant. In addition to CCS, also other possibilities have to be considered in order to limit the content of carbon dioxide in the atmosphere. The methanation of carbon dioxide is at least an interesting possibility in order to feed the greenhouse gas to an additional cycle of usage.

Methane production and methane consumption: a review of processes underlying wetland methane fluxes.

NARCIS (Netherlands)

Segers, R.

1998-01-01

Potential rates of both methane production and methane consumption vary over three orders of magnitude and their distribution is skew. These rates are weakly correlated with ecosystem type, incubation temperature, in situ aeration, latitude, depth and distance to oxic/anoxic interface. Anaerobic

Environmental impact of coal mine methane emissions and responding strategies in China

Energy Technology Data Exchange (ETDEWEB)

Cheng, Y.P.; Wang, L.; Zhang, X.L. [China University of Mining & Technology, Xuzhou (China)

2011-01-15

The impact on global climate change from coal mine methane emissions in China has been drawing attention as coal production has powered its economic development. Data on coal mine methane emissions from the State Administration of Coal Mine Safety of China has been analyzed. It is estimated that the methane emission from coal mining in China reached 20 billions of cubic meters in 2008, most of which comes from state-owned coal mines with high-gas content. China releases six times as much of methane from coal mines as compared to the United States. However, Chinese methane emission from coal production accounts for only a very small proportion on the environmental impact when compared to emissions of carbon dioxide from fossil fuel consumption. The Chinese government has shown environmental awareness and resolution on the mitigation and utilization of coal mine methane emissions. Measures have been taken to implement the programs of mitigation and utilization of coal mine methane, and at the same time, to ensure mining safety. Nearly 7.2 billions of cubic meters of methane were drained from the coal mines, and 32% of it was utilized in 2008. The slow advancement of technologies for the drainage and utilization of low-concentration methane from ventilation air hinders the progress of mitigation of atmospheric methane and the utilization of coal mine methane emissions.

Methane Emissions from Landfill: Isotopic Evidence for Low Percentage of Oxidation from Gas Wells, Active and Closed Cells

Science.gov (United States)

Lowry, David; Fisher, Rebecca; Zazzeri, Giulia; al-Shalaan, Aalia; France, James; Lanoisellé, Mathias; Nisbet, Euan

2017-04-01

Large landfill sites remain a significant source of methane emissions in developed and developing countries, with a global estimated flux of 29 Tg / yr in the EDGAR 2008 database. This is significantly lower than 20 years ago due to the introduction of gas extraction systems, but active cells still emit significant amounts of methane before the gas is ready for extraction. Historically the methane was either passively oxidized through topsoil layers or flared. Oxidation is still the primary method of methane removal in many countries, and covered, remediated cells across the world continue to emit small quantities of methane. The isotopic signatures of methane from landfill gas wells, and that emitted from active and closed cells have been characterized for more than 20 UK landfills since 2011, with more recent work in Kuwait and Hong Kong. Since 2013 the emission plumes have been identified by a mobile measurement system (Zazzeri et al., 2015). Emissions in all 3 countries have a characteristic δ13C signature of -58 ± 3 ‰ dominated by emissions from the active cells, despite the hot, dry conditions of Kuwait and the hot, humid conditions of Hong Kong. Gas well samples define a similar range. Surface emissions from closed cells and closed landfills are mostly in the range -56 to -52 ‰Ṫhese are much more depleted values than those observed in the 1990s (up to -35 ) when soil oxidation was the dominant mechanism of methane removal. Calculations using isotopic signatures of the amount of methane oxidised in these closed areas before emission to atmosphere range from 5 to 15%, but average less than 10%, and are too small to calculate from the high-emitting active cells. Compared to other major methane sources, landfills have the most consistent isotopic signature globally, and are distinct from the more 13C-enriched natural gas, combustion and biomass burning sources. Zazzeri, G. et al. (2015) Plume mapping and isotopic characterization of anthropogenic methane

Implications of overestimated anthropogenic CO2 emissions on East Asian and global land CO2 flux inversion

Science.gov (United States)

Saeki, Tazu; Patra, Prabir K.

2017-12-01

Measurement and modelling of regional or country-level carbon dioxide (CO2) fluxes are becoming critical for verification of the greenhouse gases emission control. One of the commonly adopted approaches is inverse modelling, where CO2 fluxes (emission: positive flux, sink: negative flux) from the terrestrial ecosystems are estimated by combining atmospheric CO2 measurements with atmospheric transport models. The inverse models assume anthropogenic emissions are known, and thus the uncertainties in the emissions introduce systematic bias in estimation of the terrestrial (residual) fluxes by inverse modelling. Here we show that the CO2 sink increase, estimated by the inverse model, over East Asia (China, Japan, Korea and Mongolia), by about 0.26 PgC year-1 (1 Pg = 1012 g) during 2001-2010, is likely to be an artifact of the anthropogenic CO2 emissions increasing too quickly in China by 1.41 PgC year-1. Independent results from methane (CH4) inversion suggested about 41% lower rate of East Asian CH4 emission increase during 2002-2012. We apply a scaling factor of 0.59, based on CH4 inversion, to the rate of anthropogenic CO2 emission increase since the anthropogenic emissions of both CO2 and CH4 increase linearly in the emission inventory. We find no systematic increase in land CO2 uptake over East Asia during 1993-2010 or 2000-2009 when scaled anthropogenic CO2 emissions are used, and that there is a need of higher emission increase rate for 2010-2012 compared to those calculated by the inventory methods. High bias in anthropogenic CO2 emissions leads to stronger land sinks in global land-ocean flux partitioning in our inverse model. The corrected anthropogenic CO2 emissions also produce measurable reductions in the rate of global land CO2 sink increase post-2002, leading to a better agreement with the terrestrial biospheric model simulations that include CO2-fertilization and climate effects.

Methane emissions from a high arctic valley: findings and challenges

DEFF Research Database (Denmark)

Mastepanov, Mikhail; Sigsgaard, Charlotte; Ström, Lena

2008-01-01

Wet tundra ecosystems are well-known to be a significant source of atmospheric methane. With the predicted stronger effect of global climate change on arctic terrestrial ecosystems compared to lower-latitudes, there is a special obligation to study the natural diversity and the range of possible...... feedback effects on global climate that could arise from Arctic tundra ecosystems. One of the prime candidates for such a feedback mechanism is a potential change in the emissions of methane. Long-term datasets on methane emissions from high arctic sites are almost non-existing but badly needed...... for analyses of controls on interannual and seasonal variations in emissions. To help fill this gap we initiated a measurement program in a productive high arctic fen in the Zackenberg valley, NE Greenland. Methane flux measurements have been carried out at the same location since 1997. Compared...

Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials.

Science.gov (United States)

Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Hoefman, Sven; De Vos, Paul; Boeckx, Pascal; Boon, Nico

2014-04-01

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (~20 % (v/v)) and low (~100 ppmv) methane mixing ratios. Methylocystis parvus in autoclaved aerated concrete (AAC) exhibited the highest methane removal rate at high (28.5 ± 3.8 μg CH₄ g⁻¹ building material h⁻¹) and low (1.7 ± 0.4 μg CH₄ g⁻¹ building material h⁻¹) methane mixing ratio. Due to the higher volume of pores with diameter >5 μm compared to other materials tested, AAC was able to adsorb more bacteria which might explain for the higher methane removal observed. The total methane and carbon dioxide-carbon in the headspace was decreased for 65.2 ± 10.9 % when M. parvus in Ytong was incubated for 100 h. This study showed that immobilized MOB on building materials could be used to remove methane from the air and also act as carbon sink.

Rain increases methane production and methane oxidation in a boreal thermokarst bog

Science.gov (United States)

Neumann, R. B.; Moorberg, C.; Turner, J.; Wong, A.; Waldrop, M. P.; Euskirchen, E. S.; Edgar, C.; Turetsky, M. R.

2017-12-01

Bottom-up biogeochemical models of wetland methane emissions simulate the response of methane production, oxidation and transport to wetland conditions and environmental forcings. One reason for mismatches between bottom-up and top-down estimates of emissions is incomplete knowledge of factors and processes that control microbial rates and methane transport. To advance mechanistic understanding of wetland methane emissions, we conducted a multi-year field investigation and plant manipulation experiment in a thermokarst bog located near Fairbanks, Alaska. The edge of the bog is experiencing active permafrost thaw, while the center of the bog thawed 50 to 100 years ago. Our study, which captured both an average year and two of the wettest years on record, revealed how rain interacts with vascular vegetation and recently thawed permafrost to affect methane emissions. In the floating bog, rain water warmed and oxygenated the subsurface, but did not alter soil saturation. The warmer peat temperatures increased both microbial methane production and plant productivity at the edge of the bog near the actively thawing margin, but minimally altered microbial and plant activity in the center of the bog. These responses indicate processes at the edge of the bog were temperature limited while those in the center were not. The compounding effect of increased microbial activity and plant productivity at the edge of the bog doubled methane emissions from treatments with vascular vegetation during rainy years. In contrast, methane emissions from vegetated treatments in the center of the bog did not change with rain. The oxygenating influence of rain facilitated greater methane oxidation in treatments without vascular vegetation, which offset warming-induced increases in methane production at the edge of the bog and decreased methane emissions in the center of the bog. These results elucidate the complex and spatially variable response of methane production and oxidation in

Methodology for methane emission inventory from Snam transmission system

International Nuclear Information System (INIS)

Premoli, M.; Riva, A.

1997-01-01

Methane, the main component of natural gas, is recognised as one of the most important contributors of the greenhouse effect, responsible for about 22% of the total. Several industries of natural gas, among which Snam, have undertaken intensive programs focused on the quantification of the total amounts of methane emitted in their operating activities. Snam elaborated a scientifically reliable methodology, for evaluating the annual methane emissions from its transmission system, based on a statistic approach using specific 'activity factors', that are the emitting equipment population and the frequency of emitting events, and emission factors. Part of the latter are based on GRI-EPA emission factors calculated for natural gas systems in the U.S. and adjusted to Snam system, and the other were measured during a field campaign on a random sample of previously identified large emission sources in Snam compressor and metering and regulating stations. The study showed that the methane release to the air from Snam natural gas transmission system was only the 0.1% of the total amount of methane in the natural gas imported and produced in Italy in 1993. (au)

Rising methane emissions from northern wetlands associated with sea ice decline

Science.gov (United States)

Parmentier, Frans-Jan W.; Zhang, Wenxin; Zhu, Xudong; van Huissteden, Jacobus; Hayes, Daniel J.; Zhuang, Qianlai; Christensen, Torben R.; McGuire, A. David

2015-01-01

The Arctic is rapidly transitioning toward a seasonal sea ice-free state, perhaps one of the most apparent examples of climate change in the world. This dramatic change has numerous consequences, including a large increase in air temperatures, which in turn may affect terrestrial methane emissions. Nonetheless, terrestrial and marine environments are seldom jointly analyzed. By comparing satellite observations of Arctic sea ice concentrations to methane emissions simulated by three process-based biogeochemical models, this study shows that rising wetland methane emissions are associated with sea ice retreat. Our analyses indicate that simulated high-latitude emissions for 2005–2010 were, on average, 1.7 Tg CH4 yr−1 higher compared to 1981–1990 due to a sea ice-induced, autumn-focused, warming. Since these results suggest a continued rise in methane emissions with future sea ice decline, observation programs need to include measurements during the autumn to further investigate the impact of this spatial connection on terrestrial methane emissions.

Quantifying Anthropogenic Dust Emissions

Science.gov (United States)

Webb, Nicholas P.; Pierre, Caroline

2018-02-01

Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

Utilization of coalbed methane

Energy Technology Data Exchange (ETDEWEB)

Gustavson, J.B. [Gustavson Associates Inc., Boulder, CO (United States)

1996-02-01

Substantial progress has been made in capturing coalbed methane (CBM gas), which constitutes a valuable source of clean burning energy. It is of importance to study the various potential uses of coalbed methane and to understand the various technologies required, as well as their economics and any institutional constraints. In industrialised countries, the uses of coalbed methane are almost solely dependent on microeconomics; coalbed methane must compete for a market against natural gas and other energy sources - and frequently, coalbed methane is not competitive against other energy sources. In developing countries, on the other hand, particularly where other sources of energy are in short supply, coalbed methane economics yield positive results. Here, constraints to development of CBM utilization are mainly lack of technology and investment capital. Sociological aspects such as attitude and cultural habits, may also have a strong negative influence. This paper outlines the economics of coalbed methane utilization, particularly its competition with natural gas, and touches upon the many different uses to which coalbed methane may be applied. 24 refs., 4 figs.

Doses from radioactive methane

International Nuclear Information System (INIS)

Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

1990-01-01

A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

HIGHTEX: a computer program for the steady-state simulation of steam-methane reformers used in a nuclear process heat plant

International Nuclear Information System (INIS)

Tadokoro, Yoshihiro; Seya, Toko

1977-08-01

This report describes a computational model and the input procedure of HIGHTEX, a computer program for steady-state simulation of the steam-methane reformers used in a nuclear process heat plant. The HIGHTEX program simulates rapidly a single reformer tube, and treats the reactant single-phase in the two-dimensional catalyst bed. Output of the computer program is radial distributions of temperature and reaction products in the catalyst-packed bed, pressure loss of the packed bed, stress in the reformer tube, hydrogen permeation rate through the reformer tube, heat rate of reaction, and heat-transfer rate between helium and process gas. The running time (cpu) for a 9m-long bayonet type reformer tube is 12 min with FACOM-230/75. (auth.)

Martian methane plume models for defining Mars rover methane source search strategies

Science.gov (United States)

Nicol, Christopher; Ellery, Alex; Lynch, Brian; Cloutis, Ed

2018-07-01

The detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.

The importance of addressing methane emissions as part of a comprehensive greenhouse gas management strategy

Energy Technology Data Exchange (ETDEWEB)

Bylin, Carey [U.S. Environmental Protection Agency (EPA), Washington, DC (United States); Robinson, Donald; Cacho, Mariella; Russo, Ignacio; Stricklin, Eric [ICF International, Fairfax, VA (United States); Rortveit, Geir Johan [Statoil, Stavanger (Norway); Chakraborty, A.B. [Oil and Natural Gas Corporation Ltda. (ONGC), Dehradun (India); Pontiff, Mike [Newfield, The Woodlands, TX, (United States); Smith, Reid [British Petroleum (BP), London (United Kingdom)

2012-07-01

Given the climate forcing properties of greenhouse gases (GHGs) and the current state of the global economy, it is imperative to mitigate emissions of GHGs cost-effectively. Typically, CO{sub 2} is the main focus of most companies' and governments' GHG emissions reductions strategies. However, when considering near-term goals, it becomes clear that emissions reductions of other GHGs must be pursued. One such GHG is methane, the primary component of natural gas. Reducing GHG emissions and generating profits are not necessarily a mutually exclusive endeavor as illustrated by the United States Environmental Protection Agency's (EPA) Natural Gas STAR Program. The Program is a worldwide voluntary, flexible partnership of oil and gas companies which promotes cost-effective technologies and practices to reduce methane emissions from oil and natural gas operations. In an effort to meet environmental goals without sacrificing profitability, Natural Gas STAR partner companies have identified over 60 cost-effective best practices to reduce their methane emissions, which they report to the EPA. This paper discusses: 1) the importance of reducing methane emissions and its economic impact, 2) a comparison of methane emission reduction projects relative to other greenhouse gas reduction projects in the oil and gas industry, 3) the value of source-specific methane emissions inventories, and 4) methane emission reduction opportunities from hydraulically fractured gas well completions and centrifugal compressor wet seals. From the analyses and examples in this paper, it can be concluded that methane emission reduction projects can be readily identified, profitable, and effective in mitigating global climate change. (author)

Can EC and UK national methane emission inventories be verified using high precision stable isotope data?

International Nuclear Information System (INIS)

Lowry, D.; Holmes, C.W.; Nisbet, E.G.; Rata, N.D.

2002-01-01

The main anthropogenic sources of methane in industrialised countries (landfill/waste treatment, gas storage and distribution, coal) are far easier to reduce than CO 2 sources and the implementation of reduction strategies is potentially profitable. Statistical databases of methane emissions need independent external verification and carbon isotope data provide one way of estimating the expected source mix for each country if the main source types have been characterised isotopically. Using this method each country participating in the CORINAIR 94 database has been assigned an expected isotopic value for its emissions. The averaged δ 13 C of methane emitted from the CORINAIR region of Europe, based on total emissions of each country is -55.4 per mille for 1994. This European source mix can be verified using trajectory analysis for air samples collected at background stations. Methane emissions from the UK, and particularly the London region, have undergone more detailed analysis using data collected at the Royal Holloway site on the western fringe of London. If the latest emissions inventory figures are correct then the modelled isotopic change in the UK source mix is from -48.4 per mille in 1990 to -50.7 per mille in 1997. This represents a reduction in emissions of 25% over a 7-year period, important in meeting proposed UK greenhouse gas reduction targets. These changes can be tested by the isotopic analysis of air samples at carefully selected coastal background and interior sites. Regular sampling and isotopic analysis coupled with back trajectory analysis from a range of sites could provide an important tool for monitoring and verification of EC and UK methane emissions in the run-up to 2010. (author)

Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials

NARCIS (Netherlands)

Ganendra, G; De Muynck, W; Ho, A.; Hoefman, S.; De Vos, P.; Boeckx, P.; Boon, N.

2014-01-01

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (similar to 20 % (v/v)) and low (similar to 100 ppmv) methane

Response of the Black Sea methane budget to massive short-term submarine inputs of methane

DEFF Research Database (Denmark)

Schmale, O.; Haeckel, M.; McGinnis, D. F.

2011-01-01

A steady state box model was developed to estimate the methane input into the Black Sea water column at various water depths. Our model results reveal a total input of methane of 4.7 Tg yr(-1). The model predicts that the input of methane is largest at water depths between 600 and 700 m (7......% of the total input), suggesting that the dissociation of methane gas hydrates at water depths equivalent to their upper stability limit may represent an important source of methane into the water column. In addition we discuss the effects of massive short-term methane inputs (e. g. through eruptions of deep......-water mud volcanoes or submarine landslides at intermediate water depths) on the water column methane distribution and the resulting methane emission to the atmosphere. Our non-steady state simulations predict that these inputs will be effectively buffered by intense microbial methane consumption...

Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters

Science.gov (United States)

Ward, B. B.; Kilpatrick, K. A.; Novelli, P. C.; Scranton, M. I.

1987-01-01

Measured biological oxidation rates of methane in near-surface waters of the Cariaco Basin are compared with the diffusional fluxes computed from concentration gradients of methane in the surface layer. Methane fluxes and oxidation rates were investigated in surface waters, at the oxic/anoxic interface, and in deep anoxic waters. It is shown that the surface-waters oxidation of methane is a mechanism which modulates the flux of methane from marine waters to the atmosphere.

Improved methane removal in exhaust gas from biogas upgrading process using immobilized methane-oxidizing bacteria.

Science.gov (United States)

Sun, Meng-Ting; Yang, Zhi-Man; Fu, Shan-Fei; Fan, Xiao-Lei; Guo, Rong-Bo

2018-05-01

Methane in exhaust gas from biogas upgrading process, which is a greenhouse gas, could cause global warming. The biofilter with immobilized methane-oxidizing bacteria (MOB) is a promising approach for methane removal, and the selections of inoculated MOB culture and support material are vital for the biofilter. In this work, five MOB consortia were enriched at different methane concentrations. The MOB-20 consortium enriched at the methane concentration of 20.0% (v/v) was then immobilized on sponge and two particle sizes of volcanic rock in biofilters to remove methane in exhaust gas from biogas upgrading process. Results showed that the immobilized MOB performed more admirable methane removal capacity than suspended cells. The immobilized MOB on sponge reached the highest methane removal efficiency (RE) of 35%. The rough surface, preferable hydroscopicity, appropriate pore size and particle size of support material might favor the MOB immobilization and accordingly methane removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

Project identification for methane reduction options

Energy Technology Data Exchange (ETDEWEB)

Kerr, T.

1996-12-31

This paper discusses efforts directed at reduction in emission of methane to the atmosphere. Methane is a potent greenhouse gas, which on a 20 year timeframe may present a similar problem to carbon dioxide. In addition, methane causes additional problems in the form of smog and its longer atmospheric lifetime. The author discusses strategies for reducing methane emission from several major sources. This includes landfill methane recovery, coalbed methane recovery, livestock methane reduction - in the form of ruminant methane reduction and manure methane recovery. The author presents examples of projects which have implemented these ideas, the economics of the projects, and additional gains which come from the projects.

LOW-POWER SOLUTION FOR EDDY COVARIANCE MEASUREMENTS OF METHANE FLUX

Science.gov (United States)

Anderson, T.; Burba, G. G.; Komissarov, A.; McDermitt, D. K.; Xu, L.; Zona, D.; Oechel, W. C.; Schedlbauer, J. L.; Oberbauer, S. F.; Riensche, B.; Allyn, D.

2009-12-01

night to about 4 mg m-2 h-1 in midday in arctic tundra. Observed fluxes were within the ranges reported in the literature for a number of wetlands in North America, including the Everglades wetlands. Diurnal patterns were similar to those measured by closed-path sensors. The LI-7700 open-path analyzer is a valuable tool for measuring long-term eddy fluxes of methane due to the good frequency response and undisturbed in-situ sampling. It enables long-term deployment of permanent, portable or mobile CH4 flux stations at remote locations with high CH4 production, because it can be powered by a solar panels or a small generator. Authors appreciate help and support provided by the LI-COR Engineering Team, Barrow Arctic Science Consortium (BASC), and numerous colleagues involved in measurements, logistics, and maintenance of the experimental field sites. This project was supported by the Small Business Innovation Research (SBIR) and Small Business Technology Transfer Program (STTR) program of the Department of Energy (DOE), Grant Number DE-FG02-05ER84283.

Global Methane Initiative

Science.gov (United States)

The Global Methane Initiative promotes cost-effective, near-term methane recovery through partnerships between developed and developing countries, with participation from the private sector, development banks, and nongovernmental organizations.

Evaluation of anthropogenic urban soils. Final report; Bewertung anthropogener Stadtboeden. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Blume, H.P.; Schleuss, U. [eds.

1997-12-31

The research project `Evaluation of Anthropogenic Urban Soils` was subsidized by the German Federal Ministry of Education, Science, Research and Technology and adviced by the working group `Stadtboeden` of the German Society of Soil Science. It was realized as a cooperation between the universities of Berlin (TU), Halle-Wittenberg, Hohenheim, Kiel and Rostock and had three objectives: - to characterize soils developed from anthropogenic substratums (`urban soils`), - to figure out distribution patterns of such soils and - to verify whether urban soils could be evaluated according to their filtering and habitat function in the same way as soils developed from natural parent material. Evaluation methods based on easily obtainable field data had to be adapted to `urban soils` respectively developed anew. For that reason some typical soils of anthropogenic lithogenesis had to be examined between 1993 and 1996 both on their importance as habitats for plants and soil organisms and on their filtering, buffering and transforming capacities for organic and inorganic pollutants. Accordingly representative `urban soils` were gathered in the towns of Berlin, Eckernfoerde, Essen, Halle, Kiel, Rostock and Stuttgart; these soils had developed from technogenic substratums (brick and mortar debris, municipal waste, ashes, slag, sludge) and redeposited alkaline resp. acidic natural substratums (mud, coal mine and coking plant deposits). Some of the soils were influenced by ground water, and all soils developed from the same kind of parent material belonged to different stages of development. (orig./SR) [Deutsch] Ziele des vom BMBF gefoerderten und vom Arbeitskreis Stadtboeden der Deutschen Bodenkundlichen Gesellschaft beratenen Verbundprojektes `Bewertung anthropogener Stadtboeden` waren die Charakterisierung von Boeden anthropogener Substrate, die exemplarische Ermittlung des Verteilungsmusters derartiger Boeden und die Pruefung, inwieweit sie sich aehnlich den Boeden natuerlicher

Methane Hydrates: Chapter 8

Science.gov (United States)

Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

2008-01-01

Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

Determining the flux of methane into Hudson Canyon at the edge of methane clathrate hydrate stability

Science.gov (United States)

Weinsten, A.; Navarrete, L; Ruppel, Carolyn D.; Weber, T.C.; Leonte, M.; Kellermann, M.; Arrington, E.; Valentine, D.L.; Scranton, M.L; Kessler, John D.

2016-01-01

Methane seeps were investigated in Hudson Canyon, the largest shelf-break canyon on the northern US Atlantic Margin. The seeps investigated are located at or updip of the nominal limit of methane clathrate hydrate stability. The acoustic identification of bubble streams was used to guide water column sampling in a 32 km2 region within the canyon's thalweg. By incorporating measurements of dissolved methane concentration with methane oxidation rates and current velocity into a steady-state box model, the total emission of methane to the water column in this region was estimated to be 12 kmol methane per day (range: 6 – 24 kmol methane per day). These analyses suggest this methane is largely retained inside the canyon walls below 300 m water depth, and that it is aerobically oxidized to near completion within the larger extent of Hudson Canyon. Based on estimated methane emissions and measured oxidation rates, the oxidation of this methane to dissolved CO2 is expected to have minimal influences on seawater pH. This article is protected by copyright. All rights reserved.

Role of meteorology in simulating methane seasonal cycle and growth rate

Science.gov (United States)

Ghosh, A.; Patra, P. K.; Ishijima, K.; Morimoto, S.; Aoki, S.; Nakazawa, T.

2012-12-01

Methane (CH4) is the second most important anthropogenically produced greenhouse gas whose radiative effect is comparable to that of carbon dioxide since the preindustrial time. Methane also contributes to formation of tropospheric ozone and water vapor in the stratosphere, further increasing its importance to the Earth's radiative balance. In the present study, model simulation of CH4 for three different emission scenarios has been conducted using the CCSR/NIES/FRCGC Atmospheric General Circulation Model (AGCM) based Chemistry Transport Model (ACTM) with and without nudging of meteorological parameters for the period of 1981-2011. The model simulations are compared with measurements at monthly timescale at surface monitoring stations. We show the overall trends in CH4 growth rate and seasonal cycle at most measurement sites can be fairly successfully modeled by using existing knowledge of CH4 flux trends and seasonality. Detailed analysis reveals the model simulation without nudging has greater seasonal cycle amplitude compared to observation as well as the model simulation with nudging. The growth rate is slightly overestimated for the model simulation without nudging. For better representation of regional/global flux distribution pattern and strength in the future, we are exploring various dynamical and chemical aspects in the forward model with and without nudging.

Methane emissions from U.S. natural gas operations

International Nuclear Information System (INIS)

Lott, R.A.

1992-01-01

The Gas Research Institute and the U.S. Environmental Protection Agency are cofunding and comanaging a program to evaluate methane emissions from U.S. natural gas operations. The purpose of the program is to provide an emissions inventory accurate enough for global climate modeling and for addressing the policy question of ''whether encouraging the increased use of natural gas is a viable strategy for reducing the U.S. contribution to global warming''. The program is comprised of three phases: Scoping, Methods Development, and Implementation. The purpose of Phase I was to define the problem. Phase II of the program concentrated on developing techniques for measuring steady state or fugitive emissions and for calculating the highly variable unsteady emissions from the variety of sources that comprise the gas industry. Because of the large number of sources within each source type, techniques were also developed for extrapolating emissions data to similar sources within the industry. Phase III of the program was started in early 1992 and should be completed in early 1994. The purpose of the current phase of the program is to collect sufficient data to achieve the accuracy goal of determining emissions to within ± 0.5 percent of production. Based on the limited amount of data collected to date, methane emissions from the U.S. gas industry appear to be in the range of 1 percent of production. (au) (19 refs.)

Uncertainty assessment of the breath methane concentration method to determine methane production of dairy cows

NARCIS (Netherlands)

Wu, Liansun; Groot Koerkamp, Peter W.G.; Ogink, Nico

2018-01-01

The breath methane concentration method uses the methane concentrations in the cow's breath during feed bin visits as a proxy for the methane production rate. The objective of this study was to assess the uncertainty of a breath methane concentration method in a feeder and its capability to measure

Biocatalytic conversion of methane to methanol as a key step for development of methane-based biorefineries.

Science.gov (United States)

Hwang, In Yeub; Lee, Seung Hwan; Choi, Yoo Seong; Park, Si Jae; Na, Jeong Geol; Chang, In Seop; Kim, Choongik; Kim, Hyun Cheol; Kim, Yong Hwan; Lee, Jin Won; Lee, Eun Yeol

2014-12-28

Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

Measurements of Carbon Dioxide, Methane, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

Science.gov (United States)

Yasuhara, Scott; Forgeron, Jeff; Rella, Chris; Franz, Patrick; Jacobson, Gloria; Chiao, Sen; Saad, Nabil

2013-04-01

The ability to quantify sources and sinks of carbon dioxide and methane on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to 'bottom-up' predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has proven to be effective at continental scales, becomes challenging to implement at urban scales, due to poorly understood atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, green spaces) and time (rush hours, factory shifts and shutdowns, and diurnal and seasonal variation in residential energy use). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal- resolution greenhouse gas measurements made by multiple Picarro-CRDS analyzers in Silicon Valley in California. Real-time carbon dioxide data from a 20-month period are combined with real-time carbon monoxide, methane, and acetylene to partition the observed carbon dioxide concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. Real-time wind rose data are also combined with real-time methane data to help identify the direction of local emissions of methane. High resolution WRF models are also included to better understand the dynamics of the boundary layer. The ratio between carbon dioxide and carbon monoxide is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid but frequent shifts in the balance between different carbon dioxide sources. Additional information is given by acetylene, a fossil fuel

A car-borne highly sensitive near-IR diode-laser methane detector

International Nuclear Information System (INIS)

Berezin, A G; Ershov, Oleg V; Shapovalov, Yu P

2003-01-01

A highly sensitive automated car-borne detector for measuring methane concentration in real time is designed, developed and tested under laboratory and field conditions. Measurements were made with the help of an uncooled tunable near-IR 1.65-μm laser diode. The detector consists of a multipass optical cell with a 45-m long optical path and a base length of 0.5 m. The car-borne detector is intended for monitoring the methane concentration in air from the moving car to reveal the leakage of domestic gas. The sensitivity limit (standard deviation) under field conditions is 1 ppm (20 ppb under laboratory conditions) for a measuring time of 0.4 s. The measuring technique based on the detection of a single methane line ensured a high selectivity of methane detector relative to other gases. The methane detector can be easily modified for measuring other simple-molecule gases (e.g., CO, CO 2 , HF, NO 2 , H 2 O) by replacing the diode laser and varying the parameters of the control program. (special issue devoted to the memory of academician a m prokhorov)

Mechanics of coalbed methane production

Energy Technology Data Exchange (ETDEWEB)

Creel, J C; Rollins, J B [Crawley, Gillespie and Associates, Inc. (United Kingdom)

1994-12-31

Understanding the behaviour of coalbed methane reservoirs and the mechanics of production is crucial to successful management of coalbed methane resources and projects. This paper discusses the effects of coal properties and coalbed methane reservoir characteristics on gas production rates and recoveries with a review of completion techniques for coalbed methane wells. 4 refs., 17 figs.

Natural Gas STAR Program

Science.gov (United States)

EPA’s Voluntary Methane Programs encourage oil and natural gas companies to adopt cost-effective technologies and practices that improve operational efficiency and reduce emissions of methane, a potent greenhouse gas.

Anaerobic methane oxidation rates at the sulfate-methane transition in marine sediments from Kattegat and Skagerrak (Denmark)

International Nuclear Information System (INIS)

Iversen, N.; Jorgensen, B.B.

1985-01-01

Concomitant radiotracer measurements were made of in situ rates of sulfate reduction and anaerobic methane oxidation in 2-3-m-long sediment cores. Methane accumulated to high concentrations (> 1 mM CH 4 ) only below the sulfate zone, at 1 m or deeper in the sediment. Sulfate reduction showed a broad maximum below the sediment surface and a smaller, narrow maximum at the sulfate-methane transition. Methane oxidation was low (0.002-0.1 nmol CH 4 cm -3 d -1 ) throughout the sulfate zone and showed a sharp maximum at the sulfate-methane transition, coinciding with the sulfate reduction maximum. Total anaerobic methane oxidation at two stations was 0.83 and 1.16 mmol CH 4 m -2 d -1 , of which 96% was confined to the sulfate-methane transition. All the methane that was calculated to diffuse up into the sulfate-methane transition was oxidized in this zone. The methane oxidation was equivalent to 10% of the electron donor requirement for the total measured sulfate reduction. A third station showed high sulfate concentrations at all depths sampled and the total methane oxidation was only 0.013 mmol m -2 d -1 . From direct measurements of rates, concentration gradients, and diffusion coefficients, simple calculations were made of sulfate and methane fluxes and of methane production rates

Global Assessment of Methane Gas Hydrates: Outreach for the public and policy makers

Science.gov (United States)

Beaudoin, Yannick

2010-05-01

The United Nations Environment Programme (UNEP), via its official collaborating center in Norway, GRID-Arendal, is in the process of implementing a Global Assessment of Methane Gas Hydrates. Global reservoirs of methane gas have long been the topic of scientific discussion both in the realm of environmental issues such as natural forces of climate change and as a potential energy resource for economic development. Of particular interest are the volumes of methane locked away in frozen molecules known as clathrates or hydrates. Our rapidly evolving scientific knowledge and technological development related to methane hydrates makes these formations increasingly prospective to economic development. In addition, global demand for energy continues, and will continue to outpace supply for the foreseeable future, resulting in pressure to expand development activities, with associated concerns about environmental and social impacts. Understanding the intricate links between methane hydrates and 1) natural and anthropogenic contributions to climate change, 2) their role in the carbon cycle (e.g. ocean chemistry) and 3) the environmental and socio-economic impacts of extraction, are key factors in making good decisions that promote sustainable development. As policy makers, environmental organizations and private sector interests seek to forward their respective agendas which tend to be weighted towards applied research, there is a clear and imminent need for a an authoritative source of accessible information on various topics related to methane gas hydrates. The 2008 United Nations Environment Programme Annual Report highlighted methane from the Arctic as an emerging challenge with respect to climate change and other environmental issues. Building upon this foundation, UNEP/GRID-Arendal, in conjunction with experts from national hydrates research groups from Canada, the US, Japan, Germany, Norway, India and Korea, aims to provide a multi-thematic overview of the key

Methane-fueled vehicles: A promising market for coalbed methane

International Nuclear Information System (INIS)

Deul, M.

1993-01-01

The most acceptable alternative fuel for motor vehicles is compressed natural gas (CNG). An important potential source of such gas is coalbed methane, much of which is now being wasted. Although there are no technological impediments to the use of CNG it has not been adequately promoted for a variety of reasons: structural, institutional and for coalbed gas, legal. The benefits of using CNG fuel are manifold: clean burning, low cost, abundant, and usable in any internal combustion engine. Even though more than 30,000 CNG vehicles are now in use in the U.S.A., they are not readily available, fueling stations are not easily accessible, and there is general apathy on the part of the public because of negligence by such agencies as the Department of Energy, the Department of Transportation and the Environmental Protection Agency. The economic benefits of using methane are significant: 100,000 cubic feet of methane is equivalent to 800 gallons of gasoline. Considering the many millions of cubic feet methane wasted from coal mines conservation and use of this resource is a worthy national goal

Why nuclear energy is essential to reduce anthropogenic greenhouse gas emission rates

International Nuclear Information System (INIS)

Alonso, A.; Brook, B.W.; Meneley, D.A.; Misak, J.; Blees, T.; Van Erp, J.B.

2015-01-01

Reduction of anthropogenic greenhouse gas emissions is advocated by the Intergovernmental Panel on Climate Change. To achieve this target, countries have opted for renewable energy sources, primarily wind and solar. These renewables will be unable to supply the needed large quantities of energy to run industrial societies sustainably, economically and reliably because they are inherently intermittent, depending on flexible backup power or on energy storage for delivery of base-load quantities of electrical energy. The backup power is derived in most cases from combustion of natural gas. Intermittent energy sources, if used in this way, do not meet the requirements of sustainability, nor are they economically viable because they require redundant, under- utilized investment in capacity both for generation and for transmission. Because methane is a potent greenhouse gas, the equivalent carbon dioxide value of methane may cause gas-fired stations to emit more greenhouse gas than coal-fired plants of the same power for currently reported leakage rates of the natural gas. Likewise, intermittent wind/solar photovoltaic systems backed up by gas-fu:ed power plants also release substantial amounts of carbon-dioxide- equivalent greenhouse gas to make such a combination environmentally unacceptable. In the long term, nuclear fission technology is the only known energy source that is capable of delivering the needed large quantities of energy safely, economically, reliably and in a sustainable way, both environmentally and as regards the available resource-base. (author)

Why nuclear energy is essential to reduce anthropogenic greenhouse gas emission rates

Energy Technology Data Exchange (ETDEWEB)

Alonso, A. [Univ. Politecnica de Madrid, Madrid (Spain); Brook, B.W. [Univ. of Tasmania, Hobart TAS (Australia); Meneley, D.A. [Candu Energy Inc., Mississauga, Ontario (Canada); Misak, J. [UJV-Rez, Prague (Czech Republic); Blees, T. [Science Council for Global Initiatives, Chicago, Illinois (United States); Van Erp, J.B. [Illinois Commission on Atomic Energy, Chicago, Illinois (United States)

2015-12-15

Reduction of anthropogenic greenhouse gas emissions is advocated by the Intergovernmental Panel on Climate Change. To achieve this target, countries have opted for renewable energy sources, primarily wind and solar. These renewables will be unable to supply the needed large quantities of energy to run industrial societies sustainably, economically and reliably because they are inherently intermittent, depending on flexible backup power or on energy storage for delivery of base-load quantities of electrical energy. The backup power is derived in most cases from combustion of natural gas. Intermittent energy sources, if used in this way, do not meet the requirements of sustainability, nor are they economically viable because they require redundant, under- utilized investment in capacity both for generation and for transmission. Because methane is a potent greenhouse gas, the equivalent carbon dioxide value of methane may cause gas-fired stations to emit more greenhouse gas than coal-fired plants of the same power for currently reported leakage rates of the natural gas. Likewise, intermittent wind/solar photovoltaic systems backed up by gas-fu:ed power plants also release substantial amounts of carbon-dioxide- equivalent greenhouse gas to make such a combination environmentally unacceptable. In the long term, nuclear fission technology is the only known energy source that is capable of delivering the needed large quantities of energy safely, economically, reliably and in a sustainable way, both environmentally and as regards the available resource-base. (author)

Is methane a new therapeutic gas?

Directory of Open Access Journals (Sweden)

Liu Wenwu

2012-09-01

Full Text Available Abstract Background Methane is an attractive fuel. Biologically, methanogens in the colon can use carbon dioxide and hydrogen to produce methane as a by-product. It was previously considered that methane is not utilized by humans. However, in a recent study, results demonstrated that methane could exert anti-inflammatory effects in a dog small intestinal ischemia-reperfusion model. Point of view Actually, the bioactivity of methane has been investigated in gastrointestinal diseases, but the exact mechanism underlying the anti-inflammatory effects is required to be further elucidated. Methane can cross the membrane and is easy to collect due to its abundance in natural gas. Although methane is flammable, saline rich in methane can be prepared for clinical use. These seem to be good news in application of methane as a therapeutic gas. Conclusion Several problems should be resolved before its wide application in clinical practice.

Operating a locomotive on liquid methane fuel

International Nuclear Information System (INIS)

Stolz, J.L.

1992-01-01

This paper reports that several years ago, Burlington Northern Railroad looked into the feasibility of operating a diesel railroad locomotive to also run on compressed natural gas in a dual-fuel mode. Recognizing the large volume of on-board storage required and other limitations of CNG in the application, a program was begun to fuel a locomotive with liquefied natural gas. Because natural gas composition can vary with source and processing, it was considered desirable to use essentially pure liquid methane as the engine fuel. Initial testing results show the locomotive system achieved full diesel-rated power when operating on liquid methane and with equivalent fuel efficiency. Extended testing, including an American Association of Railroad 500-hour durability test, was undertaken to obtain information on engine life, wear rate and lubrication oil life

Determination of soil-entrapped methane

Energy Technology Data Exchange (ETDEWEB)

Alberto, M.C.R.; Neue, H.U.; Lantin, R.S.; Aduna, J.B. [Soil and Water Sciences Division, Manila (Philippines)

1996-12-31

A sampling method was developed and modified to sample soil from paddy fields for entrapped methane determination. A 25-cm long plexiglass tube (4.4-cm i.d.) fitted with gas bag was used to sample soil and entrapped gases to a depth of 15-cm. The sampling tube was shaken vigorously to release entrapped gases. Headspace gas in sampling tube and gas bag was analyzed for methane. The procedure was verified by doing field sampling weekly at an irrigated ricefield in the IRRI Research Farm on a Maahas clay soil. The modified sampling method gave higher methane concentration because it eliminated gas losses during sampling. The method gave 98% {+-} 5 recovery of soil-entrapped methane. Results of field sampling showed that the early growth stage of the rice plant, entrapped methane increased irrespective of treatment. This suggests that entrapped methane increased irrespective of treatment. This suggests that entrapped methane was primarily derived from fermentation of soil organic matter at the early growth stage. At the latter stage, the rice plant seems to be the major carbon source for methane production. 7 refs., 4 figs., 4 tabs.

Oxidative coupling of methane using inorganic membrane reactor

Energy Technology Data Exchange (ETDEWEB)

Ma, Y.H.; Moser, W.R.; Dixon, A.G. [Worcester Polytechnic Institute, MA (United States)] [and others

1995-12-31

The goal of this research is to improve the oxidative coupling of methane in a catalytic inorganic membrane reactor. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and relatively higher yields than in fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gas phase reactions, which are believed to be a main route for formation of CO{sub x} products. Such gas phase reactions are a cause for decreased selectivity in oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Modeling work which aimed at predicting the observed experimental trends in porous membrane reactors was also undertaken in this research program.

Possible influence of anthropogenic aerosols on cirrus clouds and anthropogenic forcing

Directory of Open Access Journals (Sweden)

J. E. Penner

2009-02-01

Full Text Available Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We use a version of the aerosol model that predicts sulfate number and mass concentrations in 3-modes and includes the formation of sulfate aerosol through homogeneous binary nucleation as well as a version that only predicts sulfate mass. The 3-mode version best represents the Aitken aerosol nuclei number concentrations in the upper troposphere which dominated ice crystal residues in the upper troposphere. Fossil fuel and biomass burning soot aerosols with this version exert a radiative forcing of −0.3 to −0.4 Wm⁻² while anthropogenic sulfate aerosols and aircraft aerosols exert a forcing of −0.01 to 0.04 Wm⁻² and −0.16 to −0.12 Wm⁻², respectively, where the range represents the forcing from two parameterizations for ice nucleation. The sign of the forcing in the mass-only version of the model depends on which ice nucleation parameterization is used and can be either positive or negative. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

Investigation of the Methane Hydrate Formation by Cavitation Jet

Science.gov (United States)

Morita, H.; Nagao, J.

2015-12-01

Methane hydrate (hereafter called "MH") is crystalline solid compound consisting of hydrogen-bonded water molecules forming cages and methane gas molecules enclosed in the cage. When using MH as an energy resource, MH is dissociated to methane gas and water and collect only the methane gas. The optimum MH production method was the "depressurization method". Here, the production of MH means dissociating MH in the geologic layers and collecting the resultant methane gas by production systems. In the production of MH by depressurization method, MH regeneration was consider to important problem for the flow assurance of MH production system. Therefore, it is necessary to clarify the effect of flow phenomena in the pipeline on hydrate regeneration. Cavitation is one of the flow phenomena which was considered a cause of MH regeneration. Large quantity of microbubbles are produced by cavitation in a moment, therefore, it is considered to promote MH formation. In order to verify the possible of MH regeneration by cavitation, it is necessary to detailed understanding the condition of MH formation by cavitation. As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on MH formation using by cavitation. The primary objective of this study is to demonstrate the formation MH by using cavitation in the various temperature and pressure condition, and to clarify the condition of MH formation by using observation results.

Detection of Abiotic Methane in Terrestrial Continental Hydrothermal Systems: Implications for Methane on Mars

Science.gov (United States)

Socki, Richard A.; Niles, Paul B.; Gibson, Everett K., Jr.; Romanek, Christopher S.; Zhang, Chuanlun L.; Bissada, Kadry K.

2008-01-01

The recent detection of methane in the Martian atmosphere and the possibility that its origin could be attributed to biological activity, have highlighted the importance of understanding the mechanisms of methane formation and its usefulness as a biomarker. Much debate has centered on the source of the methane in hydrothermal fluids, whether it is formed biologically by microorganisms, diagenetically through the decomposition of sedimentary organic matter, or inorganically via reduction of CO2 at high temperatures. Ongoing research has now shown that much of the methane present in sea-floor hydrothermal systems is probably formed through inorganic CO2 reduction processes at very high temperatures (greater than 400 C). Experimental results have indicated that methane might form inorganically at temperatures lower still, however these results remain controversial. Currently, methane in continental hydrothermal systems is thought to be formed mainly through the breakdown of sedimentary organic matter and carbon isotope equilibrium between CO2 and CH4 is thought to be rarely present if at all. Based on isotopic measurements of CO2 and CH4 in two continental hydrothermal systems, we suggest that carbon isotope equilibration exists at temperatures as low as 155 C. This would indicate that methane is forming through abiotic CO2 reduction at lower temperatures than previously thought and could bolster arguments for an abiotic origin of the methane detected in the martian atmosphere.

Quantification of strong emissions of methane in the Arctic using spectral measurements from TANSO-FTS and IASI

Science.gov (United States)

Bourakkadi, Zakia; Payan, Sébastien; Bureau, Jérôme

2015-04-01

Methane is the second most important greenhouse gas after the carbon dioxide but it is 25 times more effective in contributing to the radiative forcing than the carbon dioxide(1). Since the pre-industrial times global methane concentration have more than doubled in the atmosphere. This increase is generally caused by anthropogenic activities like the massif use and extraction of fossil fuel, rice paddy agriculture, emissions from landfills... In recent years, several studies show that climate warming and thawing of permafrost act on the mobilization of old stored carbon in Arctic causing a sustained release of methane to the atmosphere(2),(3),(4). The methane emissions from thawing permafrost and methane hydrates in the northern circumpolar region will become potentially important in the end of the 21st centry because they could increase dramatically due to the rapid climate warming of the Artic and the large carbon pools stored there. The objective of this study is to evaluate and quantify methane strong emissions in this region of the globe using spectral measurements from the Thermal And Near Infrared Sensor for carbon Observations-Fourier Transform Spectrometer (TANSO-FTS) and the Infrared Atmospheric Sounding Interferometer (IASI). We use also the LMDZ-PYVAR model to simulate methane fluxes and to estimate how they could be observed by Infrared Sounders from space. To select spectra with high values of methane we developed a statistical approach based on the singular value decomposition. Using this approach we can identify spectra over the important emission sources of methane and we can by this way reduce the number of spectra to retrieve by an line-by-line radiative transfer model in order to focus on those which contain high amount of methane. In order to estimate the capacity of TANSO-FTS and IASI to detect peaks of methane emission with short duration at quasi-real time, we used data from MACC (Monitoring Atmospheric Composition and Climate) simulations

Low methane flux from a constructed boreal wetland

Science.gov (United States)

Clark, M. G.; Humphreys, E.; Carey, S. K.

2016-12-01

The Sandhill Fen Watershed project in northern Alberta, Canada, is a pilot study in reconstructing a mixed upland and lowland boreal plain ecosystem. The physical construction of the 50 ha area was completed in 2012 and revegetation programs, through planting and seeding, began that same year and continued into 2013. Since then, the vegetation has developed a substantial cover over the reclaimed soil and peat substrates used to cap the engineered topography constructed from mine tailings. To monitor the dynamics of carbon cycling processes in this novel ecosystem, near weekly gas chamber measurements of methane fluxes were carried out over 3 growing seasons. Soil moisture, temperature and ion flux measurements, using Plant Root Simulator probes, were also collected alongside the gas flux plots. In the 3rd season, a transect was established in the lowlands along a moisture gradient to collect continuous reduction-oxidation potential measurements along with these other variables. Overall, methane effluxes remained low relative to what is expected for rewetted organic substrates. However, there is a trend over time towards increasing methane gas emissions that coincides with increasing fluxes of reduced metal ions and decreasing fluxes of sulphate in the fully saturated substrates. The suppressed levels of methane fluxes are possibly due to naturally occurring high levels of sulphate in the donor materials used to cap the ecosystem construction.

In search of thermogenic methane in groundwater in the Netherlands, with emphasis on the location of a historic gas well blowout

Science.gov (United States)

Schout, G.; Griffioen, J.; Hassanizadeh, S. M.; Hartog, N.

2017-12-01

Similar to the US, the Netherlands has a long history of oil & gas production, with around 2500 onshore hydrocarbon wells drilled since the late 1930s. While conventional reserves are diminishing, a governmental moratorium was put in place on shale gas exploration and production until 2023, in part due to concerns about its effects on groundwater quality. To investigate the industry's historic and potential future impact on groundwater quality in the country, a study was carried out to assess i) baseline methane concentrations and origin ii) the natural connectivity of deeper gas-bearing layers with the shallower groundwater systems. Through datamining, a dataset consisting of 12,200 groundwater analyses with methane concentrations was assembled. Furthermore, 25 additional samples were collected at targeted locations and analysed for dissolved gas molecular and isotopic composition. Methane concentrations are positively skewed with median, mean and maximum concentrations of 0.28, 2.17 and 120 mg/L, respectively. No correlation between methane concentrations and distance to hydrocarbon wells or faults is observed. In general, concentrations cannot be readily explained by factors such as the depth, geographic location, host formation and depositional environment. Thermogenic methane was first encountered at several hundred meters depth, below thick successions of marine Paleogene and Neogene clays that are present throughout the country and impede vertical flow. All methane encountered above these formations was found to be biogenic in origin, with one notable exception - a sample taken at the site of a catastrophic gas well blowout that occurred in 1965 near the village of Sleen. Combined, these findings suggest that thermogenic methane does not naturally occur in Dutch shallow groundwater and its presence can be used as an indicator of anthropogenic gas leakage. The unique Sleen blowout site was selected for a detailed investigation of the long-term effects of

Reduction of ruminant methane emissions - a win-win-win opportunity for business, development, and the environment

Energy Technology Data Exchange (ETDEWEB)

Livingston, R. [Appropriate Technology International, Washington, DC (United States)

1997-12-31

This paper describes research efforts of The Global Livestock Producers Program (GLPP) in establishing self-sustaining enterprises for cost-effective technologies (i.e., animal nutrition and genetic improvement) and global methane emissions reductions in developing world nations. The US Environmental Protection Agency has funded several studies to examine the possibilities of reducing ruminant methane emissions in India, Tanzania, Bangladesh, and Brazil. The results of the studies showed that: (1) many developing countries` production systems are inefficient, and (2) great potential exists for decreasing global methane emissions through increasing animal productivity. From this effort, the GLPP established livestock development projects in India, Zimbabwe, and Tanzania, and is developing projects for Bangladesh, Nepal, and Brazil. The GLPP has developed a proven methodology for assessing ruminant methane and incorporating methane emissions monitoring into viable projects.

Reaction of methane with coal

Energy Technology Data Exchange (ETDEWEB)

Yang, K.; Batts, B.D.; Wilson, M.A.; Gorbaty, M.L.; Maa, P.S.; Long, M.A.; He, S.J.X.; Attala, M.I. [Macquarie University, Macquarie, NSW (Australia). School of Chemistry

1997-10-01

A study of the reactivities of Australian coals and one American coal with methane or methane-hydrogen mixtures, in the range 350-400{degree}C and a range of pressures (6.0-8.3 MPa, cold) is reported. The effects of aluminophosphates (AIPO) or zeolite catalysts, with and without exchanged metals, on reactivity have also been examined. Yields of dichloromethane extractable material are increased by using a methane rather than a nitrogen atmosphere and different catalysts assist dissolution to various extends. It appears that surface exchanged catalysts are effective, but incorporating metals during AIPO lattice formation is detrimental. Aluminium phosphate catalysts are unstable to water produced during coal conversion, but are still able to increase extraction yields. For the American coal, under methane-hydrogen and a copper exchanged zeolite, 51.5% conversion was obtained, with a product selectivity close to that obtained under hydrogen alone, and with only 2% hydrogen consumption. The conversion under methane-hydrogen was also to that obtained under hydrogen alone, while a linear dependence of conversion on proportion of methane would predict a 43% conversion under methane-hydrogen. This illustrates a synergistic effect of the methane-hydrogen atmosphere for coal liquefaction using this catalyst systems. 31 refs., 5 figs., 7 tabs.

The implementation of artificial neural networks to model methane oxidation in landfill soil covers[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

Energy Technology Data Exchange (ETDEWEB)

Szeto, A.; Albanna, M.; Warith, M. [Ottawa Univ., ON (Canada). Faculty of Civil and Environmental Engineering

2009-07-01

The disposal of solid waste significantly contributes to the total anthropogenic emissions of methane (CH{sub 4}), a greenhouse gas that negatively affects climate change. The oxidation of methane in landfill bio-covers takes place through the use of methanotrophic bacteria which provides a sink for methane. The rate at which methane is biologically oxidized depends on several parameters. This study provided a better understanding of the oxidation of methane in landfill soil covers through modeling methane oxidation with artificial neural networks (ANNs). An ANN was trained and tested to model methane oxidation in various batch scale systems for 3 types of soils. Input data consisted of temperature, moisture content, soil composition and the nutrient content added to the system. Model results were in good agreement with experimental results reported by other researchers. It was concluded that the use of ANNs to model methane oxidation in batch scale bio-covers can address the large number of complicated physical and biochemical processes that occur within the landfill bio-cover. 10 refs., 7 tabs., 5 figs.

Photocatalytic conversion of methane to methanol

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

1995-12-31

A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

Emission of Methane and Heavier Alkanes From the La Brea Tar Pits Seepage Area, Los Angeles

Science.gov (United States)

Etiope, G.; Doezema, L. A.; Pacheco, C.

2017-11-01

Natural hydrocarbon (oil and gas) seeps are widespread in Los Angeles, California, due to gas migration, along faults, from numerous subsurface petroleum fields. These seeps may represent important natural contributors of methane (CH4) and heavier alkanes (C2-C4) to the atmosphere, in addition to anthropogenic fossil fuel and biogenic sources. We measured the CH4 flux by closed-chamber method from the La Brea Tar Pits park (0.1 km2), one of the largest seepage sites in Los Angeles. The gas seepage occurs throughout the park, not only from visible oil-asphalt seeps but also diffusely from the soil, affecting grass physiology. About 500 kg CH4 d-1 is emitted from the park, especially along a belt of enhanced degassing that corresponds to the 6th Street Fault. Additional emissions are from bubble plumes in the lake within the park (order of 102-103 kg d-1) and at the intersection of Wilshire Boulevard and Curson Avenue (>130 kg d-1), along the same fault. The investigated area has the highest natural gas flux measured thus far for any onshore seepage zone in the USA. Gas migration, oil biodegradation, and secondary methanogenesis altered the molecular composition of the original gas accumulated in the Salt Lake Oil Field (>300 m deep), leading to high C1/C2+ and i-butane/n-butane ratios. These molecular alterations can be important tracers of natural seepage and should be considered in the atmospheric modeling of the relative contribution of fossil fuel (anthropogenic fugitive emission and natural geologic sources) versus biogenic sources of methane, on local and global scales.

A laboratory study of anaerobic oxidation of methane in the presence of methane hydrate

Science.gov (United States)

Solem, R.; Bartlett, D.; Kastner, M.; Valentine, D.

2003-12-01

In order to mimic and study the process of anaerobic methane oxidation in methane hydrate regions we developed four high-pressure anaerobic bioreactors, designed to incubate environmental sediment samples, and enrich for populations of microbes associated with anaerobic methane oxidation (AMO). We obtained sediment inocula from a bacterial mat at the southern Hydrate Ridge, Cascadia, having cell counts approaching 1010 cells/cc. Ultimately, our goal is to produce an enriched culture of these microbes for characterization of the biochemical processes and chemical fluxes involved, as well as the unique adaptations required for, AMO. Molecular phylogenetic information along with results from fluorescent in situ hybridization indicate that consortia of Archaea and Bacteria are present which are related to those previously described for marine sediment AMO environments. Using a medium of enriched seawater and sediment in a 3:1 ratio, the system was incubated at 4° C under 43 atm of methane pressure; the temperature and pressure were kept constant. We have followed the reactions for seven months, particularly the vigorous consumption rates of dissolved sulfate and alkalinity production, as well as increases in HS-, and decreases in Ca concentrations. We also monitored the dissolved inorganic C (DIC) δ 13C values. The data were reproduced, and indicated that the process is extremely sensitive to changes in methane pressure. The rates of decrease in sulfate and increase in alkalinity concentrations were complimentary and showed considerable linearity with time. When the pressure in the reactor was decreased below the methane hydrate stability field, following the methane hydrate dissociation, sulfate reduction abruptly decreased. When the pressure was restored all the reactions returned to their previous rates. Much of the methane oxidation activity in the reactor is believed to occur in association with the methane hydrate. Upon the completion of one of the experiments

Methane clathrates in the solar system.

Science.gov (United States)

Mousis, Olivier; Chassefière, Eric; Holm, Nils G; Bouquet, Alexis; Waite, Jack Hunter; Geppert, Wolf Dietrich; Picaud, Sylvain; Aikawa, Yuri; Ali-Dib, Mohamad; Charlou, Jean-Luc; Rousselot, Philippe

2015-04-01

We review the reservoirs of methane clathrates that may exist in the different bodies of the Solar System. Methane was formed in the interstellar medium prior to having been embedded in the protosolar nebula gas phase. This molecule was subsequently trapped in clathrates that formed from crystalline water ice during the cooling of the disk and incorporated in this form into the building blocks of comets, icy bodies, and giant planets. Methane clathrates may play an important role in the evolution of planetary atmospheres. On Earth, the production of methane in clathrates is essentially biological, and these compounds are mostly found in permafrost regions or in the sediments of continental shelves. On Mars, methane would more likely derive from hydrothermal reactions with olivine-rich material. If they do exist, martian methane clathrates would be stable only at depth in the cryosphere and sporadically release some methane into the atmosphere via mechanisms that remain to be determined. In the case of Titan, most of its methane probably originates from the protosolar nebula, where it would have been trapped in the clathrates agglomerated by the satellite's building blocks. Methane clathrates are still believed to play an important role in the present state of Titan. Their presence is invoked in the satellite's subsurface as a means of replenishing its atmosphere with methane via outgassing episodes. The internal oceans of Enceladus and Europa also provide appropriate thermodynamic conditions that allow formation of methane clathrates. In turn, these clathrates might influence the composition of these liquid reservoirs. Finally, comets and Kuiper Belt Objects might have formed from the agglomeration of clathrates and pure ices in the nebula. The methane observed in comets would then result from the destabilization of clathrate layers in the nuclei concurrent with their approach to perihelion. Thermodynamic equilibrium calculations show that methane-rich clathrate

Genomic selection for methane emission

DEFF Research Database (Denmark)

de Haas, Yvette; Pryce, Jennie E; Wall, Eileen

2016-01-01

Climate change is a growing area of international concern, and it is well established that the release of greenhouse gases (GHG) is a contributing factor. Of the various GHG produced by ruminants, enteric methane (CH4 ) is the most important contributor. One mitigation strategy is to reduce methane...... emission through genetic selection. Our first attempt used beef cattle and a GWAS to identify genes associated with several CH4 traits in Angus beef cattle. The Angus population consisted of 1020 animals with phenotypes on methane production (MeP), dry matter intake (DMI), and weight (WT). Additionally......, two new methane traits: residual genetic methane (RGM) and residual phenotypic methane (RPM) were calculated by adjusting CH4 for DMI and WT. Animals were genotyped using the 800k Illumina Bovine HD Array. Estimated heritabilities were 0.30, 0.19 and 0.15 for MeP, RGM and RPM respectively...

Situation of methanization installations in Haute-Normandie. Phase 2: Assessment of the regional sector. Phase 3: Development perspectives for the methanization sector in Haute-Normandie. To understand methanization. Haute-Normandie Commission of expertise on methanization

International Nuclear Information System (INIS)

Convert, Mathilde

2012-10-01

A first report proposes an analysis of the situation of methanization installations in the Haute-Normandie region while recalling the national context. It briefly reports an analysis and assessment of waste flows, processed effluents, by-products and biomass displaying an energetic potential. It describes methanization installations by addressing the different steps of the methanization process, by presenting the different digestion indicators, by briefly evoking the issue of the return-to-soil of digestates, and by presenting various operational data. Financial aspects are then addressed (investments and subsidies, financial balance of farm-based and collective installations), and an overview of methanization projects in the region and development perspectives is proposed. The second report more precisely analyses development perspectives for the methanization sector in the region through a brief assessment of the methanizable organic substrate resource, a discussion of different associated challenges (energy, agronomic, environmental and societal), a discussion of development levers and brakes, and an analysis of competitions (related to the use of industrial by-products, between processing installations, and related to agricultural soils). Another document proposes an overview of various aspects of methanization: a tool for territorial development, regulatory framework, evolution of installations in the region, assets of methanization, and role of the regional commission of expertise on methanization

Methanization in Burgundy-Franche-Comte - Figures and benchmarks. Agricultural methanization in Franche-Comte - Reflection guide for projects. Methanization development in Burgundy - Assessment 2014. Biogas sector in Burgundy. Methanization development in Burgundy - How to develop a project in Burgundy

International Nuclear Information System (INIS)

Aucordonnier, Bertrand; SIBUE, Lionel; Granger, Sylvie; Pervenchon, Frank; Forgue, Isabelle; Lirzin, Frank; Aucordonnier, Bertand; Abrahamse, Philippe; Dondaine, Regis; Rousseau, Christophe; Fevre, Jean-Michel; Carbonnier, Arnaud; Gontier, Thomas; Lemaire, Sylvie; Gallois, Vincent; Lachaize, M.

2015-03-01

A first document proposes graphs, figures and maps which illustrate various aspects of the situation and development of methanization in France and in the Burgundy-Franche-Comte region (number and location of installations, production evolution, biomass origins, biogas valorisation). A second document presents methanization (basic principles, process types, valorisation), describes agricultural methanization (substrate origin, use of final energy, use of digestates) and proposes elements of thought for methanization development regarding waste origin, project definition, various concerns (energy, environment, agriculture), digestate use and quantities, methane use, and installation sizing. A publication then proposes a synthetic overview of methanization development in Burgundy: number of supported projects, installations (evolution of their number, used materials, production), and support activities. The next publication proposes an assessment and an overview of the biogas sector in Burgundy: presentation and recommendations, assessment in terms of jobs, activities and expertise, professional education and training. The last document recalls some elements related to the methanization technique, outlines some important issues (materials, valorisation type for biogas and for digestate) to be addressed for an agricultural methanization project, and evokes benefits of methanization and some economic aspects. It also briefly describes how to start a project in the region

Modeling of methane bubbles released from large sea-floor area: Condition required for methane emission to the atmosphere

OpenAIRE

Yamamoto, A.; Yamanaka, Y.; Tajika, E.

2009-01-01

Massive methane release from sea-floor sediments due to decomposition of methane hydrate, and thermal decomposition of organic matter by volcanic outgassing, is a potential contributor to global warming. However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from the sea-floor to reach the atmosphere. Massive methane release from a large sea-floor area would result in methane-saturated seawater, thus some methane would reach the atm...

Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

Science.gov (United States)

Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

2015-12-01

Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

Methane emissions from natural wetlands

Energy Technology Data Exchange (ETDEWEB)

Meyer, J.L. [Georgia Univ., Athens, GA (United States); Burke, R.A. Jr. [Environmental Protection Agency, Athens, GA (United States). Environmental Research Lab.

1993-09-01

Analyses of air trapped in polar ice cores in conjunction with recent atmospheric measurements, indicate that the atmospheric methane concentration increased by about 250% during the past two or three hundred years (Rasmussen and Khalil, 1984). Because methane is a potent ``greenhouse`` gas, the increasing concentrations are expected to contribute to global warning (Dickinson and Cicerone, 1986). The timing of the methane increase suggests that it is related to the rapid growth of the human population and associated industrialization and agricultural development. The specific causes of the atmospheric methane concentration increase are not well known, but may relate to either increases in methane sources, decreases in the strengths of the sinks, or both.

Cryptic Methane Emissions from Upland Forest Ecosystems

Energy Technology Data Exchange (ETDEWEB)

Megonigal, Patrick [Smithsonian Institution, Washington, DC (United States); Pitz, Scott [Johns Hopkins Univ., Baltimore, MD (United States); Smithsonian Institution, Washington, DC (United States)

2016-04-19

This exploratory research on Cryptic Methane Emissions from Upland Forest Ecosystems was motivated by evidence that upland ecosystems emit 36% as much methane to the atmosphere as global wetlands, yet we knew almost nothing about this source. The long-term objective was to refine Earth system models by quantifying methane emissions from upland forests, and elucidate the biogeochemical processes that govern upland methane emissions. The immediate objectives of the grant were to: (i) test the emerging paradigm that upland trees unexpectedly transpire methane, (ii) test the basic biogeochemical assumptions of an existing global model of upland methane emissions, and (iii) develop the suite of biogeochemical approaches that will be needed to advance research on upland methane emissions. We instrumented a temperate forest system in order to explore the processes that govern upland methane emissions. We demonstrated that methane is emitted from the stems of dominant tree species in temperate upland forests. Tree emissions occurred throughout the growing season, while soils adjacent to the trees consumed methane simultaneously, challenging the concept that forests are uniform sinks of methane. High frequency measurements revealed diurnal cycling in the rate of methane emissions, pointing to soils as the methane source and transpiration as the most likely pathway for methane transport. We propose the forests are smaller methane sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements. The methods we used can be effectively implemented in order to determine if the phenomenon is widespread.

Hydrogenation of carbon to methane in reduced sponge iron, chromium, and ferrochromium

Energy Technology Data Exchange (ETDEWEB)

Qayyum, M A; Reeve, D A

1976-01-01

Hydrogenation of excess carbon to methane in reduced sponge iron, chromium and ferrochromium under isothermal and temperature-programmed conditions indicates that it is possible to control the residual carbon content of the metallized products which may be an advantage if further processing of the products is contemplated. Hydrogenation starts above 800/sup 0/C and a shrinking-core kinetic model fits the experimental data. The mean apparent activation energy for the hydrogenation of residual carbon to methane in sponge iron, chromium and ferrochromium is 21 kcal/mole.

Challenges related to methanization - Bibliographical synthesis by France Nature Environnement. Opinion of FNE on methanization: Which challenges and which desirable development? Methascope: assessment support tool for a methanization project

International Nuclear Information System (INIS)

Desaunay, Thomas; Mathien, Adeline; Dorioz, Camille; Saint-Aubin, Thibaud; Banaszuk, Agnes; Badereau, Benedicte de; Capiez, Nathalie; Zoffoli, Maxime

2014-12-01

A first document proposes a bibliographical synthesis on the various challenges related to methanization. It addresses the following issues: biogas and public policies, methanization as a natural process of transformation of organic matter, different installations for different territories, matters which can be used in methanization, biogas as a renewable and local energy which can be transformed according to needs, properties and uses of digestate, choice between composting and methanization, energetic crops, methanization and nitrates, regulation, potential risks and pollutions, economic profitability of projects. The second document states the FNE's opinion on methanization, its challenges and the associated desirable development. The third document is a guide which aims at providing knowledge on methanization, at easing dialogue between actors of a territory, and at elaborating a position and an opinion with respect to a specific methanization project on a territory

Coalbed methane: new frontier

Energy Technology Data Exchange (ETDEWEB)

Eaton, S.

2003-02-01

There are large numbers of stacked coal seams permeated with methane or natural gas in the Western Canadian Sedimentary Basin, and approximately 20 coalbed methane pilot projects are operating in the area, and brief descriptions of some of them were provided. Coalbed methane reserves have a long life cycle. A definition of coalbed methane can be a permeability challenged reservoir. It is not uncommon for coalbed methane wells to flow water for periods varying from 2 to 6 months after completion before the production of natural gas. A made-in-Canada technological solution is being developed by CDX Canada Inc., along with its American parent company. The techniques used by CDX are a marriage between coal mining techniques and oil and gas techniques. A brief description of coalification was provided. Nexen is participating in the production of gas from an Upper Mannville coal at 1 000-metres depth in a nine-well pilot project. The Alberta Foothills are considered prime exploration area since older coal is carried close to the surface by thrusting. CDX Canada uses cavitation completion in vertical wells. Cavitation consists in setting the casing above the coal seam and drilling ahead under balanced. The design of wells for coalbed methane gas is based on rock and fluid mechanics. Hydraulic fracturing completions is also used, as are tiltmeters. An enhanced coalbed methane recovery pilot project is being conducted by the Alberta Research Council at Fenn-Big Valley, located in central Alberta. It injects carbon dioxide, which shows great potential for the reduction of greenhouse gas emissions. 1 figs.

Nitrogen-fixing methane-utilizing bacteria

NARCIS (Netherlands)

Bont, de J.A.M.

1976-01-01

Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

Global diffusive fluxes of methane in marine sediments

Science.gov (United States)

Egger, Matthias; Riedinger, Natascha; Mogollón, José M.; Jørgensen, Bo Barker

2018-06-01

Anaerobic oxidation of methane provides a globally important, yet poorly constrained barrier for the vast amounts of methane produced in the subseafloor. Here we provide a global map and budget of the methane flux and degradation in diffusion-controlled marine sediments in relation to the depth of the methane oxidation barrier. Our new budget suggests that 45-61 Tg of methane are oxidized with sulfate annually, with approximately 80% of this oxidation occurring in continental shelf sediments (methane in steady-state diffusive sediments, we calculate that 3-4% of the global organic carbon flux to the seafloor is converted to methane. We further report a global imbalance of diffusive methane and sulfate fluxes into the sulfate-methane transition with no clear trend with respect to the corresponding depth of the methane oxidation barrier. The observed global mean net flux ratio between sulfate and methane of 1.4:1 indicates that, on average, the methane flux to the sulfate-methane transition accounts for only 70% of the sulfate consumption in the sulfate-methane transition zone of marine sediments.

A biomimetic methane-oxidising catalyst

Energy Technology Data Exchange (ETDEWEB)

Dalton, H [Warwick Univ., Coventry (United Kingdom). Dept. of Biological Sciences

1997-12-31

The diminishing resources of petroleum oil has meant that there has been considerable efforts in recent years to find a suitable substitute for gasoline as a transportation fuel. Methanol has been identified as a suitable substitute since it is a readily combustible fuel which can be manufactured from a number of different sources. Methane is commonly used as a starting material for the production of synthesis gas (CO + H{sub 2}) and hence methanol. It is well known that the cleavage of the C-H bond of methane is extremely difficult (bond energy is around 104 kcal/mol) and that fairly drastic conditions are required to convert methane into methanol. Temperatures around 1200 deg C and pressures of up to 100 atmospheres over metal catalysts in a series of reactions are required to effect this process. Efforts have been made to reduce the temperature and the number of steps by using lanthanide ruthenium oxide catalyst but such reactions are still thermodynamically endothermic. An energetically more efficient reaction would be the direct conversion of methane to methanol using oxygen as the oxidant: CH{sub 4} + 1/2O{sub 2} -> CH{sub 3}OH {Delta}H deg = - 30.7 kcal/mol. Such a direct oxidation route is manifest in the bacterially-mediated oxidation of methane by methanotrophic bacteria. These organisms effect the direct oxidation of methane to methanol by the enzyme methane monooxygenase (MMO) as part of the reaction sequences to oxidize methane to carbon dioxide. (14 refs.)

A biomimetic methane-oxidising catalyst

Energy Technology Data Exchange (ETDEWEB)

Dalton, H. [Warwick Univ., Coventry (United Kingdom). Dept. of Biological Sciences

1996-12-31

The diminishing resources of petroleum oil has meant that there has been considerable efforts in recent years to find a suitable substitute for gasoline as a transportation fuel. Methanol has been identified as a suitable substitute since it is a readily combustible fuel which can be manufactured from a number of different sources. Methane is commonly used as a starting material for the production of synthesis gas (CO + H{sub 2}) and hence methanol. It is well known that the cleavage of the C-H bond of methane is extremely difficult (bond energy is around 104 kcal/mol) and that fairly drastic conditions are required to convert methane into methanol. Temperatures around 1200 deg C and pressures of up to 100 atmospheres over metal catalysts in a series of reactions are required to effect this process. Efforts have been made to reduce the temperature and the number of steps by using lanthanide ruthenium oxide catalyst but such reactions are still thermodynamically endothermic. An energetically more efficient reaction would be the direct conversion of methane to methanol using oxygen as the oxidant: CH{sub 4} + 1/2O{sub 2} -> CH{sub 3}OH {Delta}H deg = - 30.7 kcal/mol. Such a direct oxidation route is manifest in the bacterially-mediated oxidation of methane by methanotrophic bacteria. These organisms effect the direct oxidation of methane to methanol by the enzyme methane monooxygenase (MMO) as part of the reaction sequences to oxidize methane to carbon dioxide. (14 refs.)

Methane in German hard coal mining

International Nuclear Information System (INIS)

Martens, P.N.; Den Drijver, J.

1995-01-01

Worldwide, hard coal mining is being carried out at ever increasing depth, and has, therefore, to cope with correspondingly increasing methane emissions are caused by coal mining. Beside carbon dioxide, chloro-fluoro-carbons (CFCs) and nitrogen oxides, methane is one of the most significant 'greenhouse' gases. It is mainly through the release of such trace gases that the greenhouse effect is brought about. Reducing methane emissions is therefore an important problem to be solved by the coal mining industry. This paper begins by highlighting some of the fundamental principles of methane in hard coal mining. The methane problem in German hard coal mining and the industry's efforts to reduce methane emissions are presented. The future development in German hard coal mining is illustrated by an example which shows how large methane volumes can be managed, while still maintaining high outputs at increasing depth. (author). 7 tabs., 10 figs., 20 refs

Quantification of methane emissions from danish landfills

DEFF Research Database (Denmark)

Scheutz, Charlotte; Mønster, Jacob; Kjeldsen, Peter

2013-01-01

Whole-landfill methane emission was quantified using a tracer technique that combines controlled tracer gas release from the landfill with time-resolved concentration measurements downwind of the landfill using a mobile high-resolution analytical instrument. Methane emissions from 13 Danish...... landfills varied between 2.6 and 60.8 kg CH4 h–1. The highest methane emission was measured at the largest (in terms of disposed waste amounts) of the 13 landfills, whereas the lowest methane emissions (2.6-6.1 kgCH4 h–1) were measured at the older and smaller landfills. At two of the sites, which had gas...... collection, emission measurements showed that the gas collection systems only collected between 30-50% of the methane produced (assuming that the produced methane equalled the sum of the emitted methane and the collected methane). Significant methane emissions were observed from disposed shredder waste...

Temporal and spatial patterns of anthropogenic disturbance at McMurdo Station, Antarctica

International Nuclear Information System (INIS)

Kennicutt, Mahlon C II; Klein, Andrew; Montagna, Paul; Palmer, Terence; Sweet, Stephen; Wade, Terry; Sericano, Jose; Denoux, Guy

2010-01-01

Human visitations to Antarctica have increased in recent decades, raising concerns about preserving the continent's environmental quality. To understand the spatial and temporal patterns of anthropogenic disturbances at the largest scientific station in Antarctica, McMurdo Station, a long-term monitoring program has been implemented. Results from the first nine years (1999-2007) of monitoring are reported. Most physical disturbance of land surfaces occurred prior to 1970 during initial establishment of the station. Hydrocarbons from fuel and anthropogenic metals occur in patches of tens to hundreds of square meters in areas of fuel usage and storage. Most soil contaminant concentrations are not expected to elicit biological responses. Past disposal practices have contaminated marine sediments with polychlorinated biphenyls (PCBs), petroleum hydrocarbons, and metals in close proximity to the station that often exceed concentrations expected to elicit biological responses. Chemical contamination and organic enrichment reduced marine benthic ecological integrity within a few hundred meters offshore of the station. Contaminants were detected in marine benthic organisms confirming bioavailability and uptake. PCBs in sediments are similar to suspected source materials, indicating minimal microbial degradation decades after release. Anthropogenic disturbance of the marine environment is likely to persist for decades. A number of monitoring design elements, indicators and methodologies used in temperate climates were effective and provide guidance for monitoring programs elsewhere in Antarctica.

Quantification of the methane concentration using anaerobic oxidation of methane coupled to extracellular electron transfer

Science.gov (United States)

A biofilm anode acclimated with acetate, acetate+methane, and methane growth media for over three years produced a steady current density of 1.6-2.3 mA/m^2 in a microbial electrochemical cell (MxC) fed with methane as the sole electron donor. Geobacter was the dominant genus for...

Identification of urban gas leaks and evaluation of methane emission inventories using mobile measurements

Science.gov (United States)

Zazzeri, Giulia; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Butler, Dominique; Lanoisellé, Mathias; Nisbet, Euan G.

2017-04-01

: Atmospheres, v. 106, p. 7427-7448 Phillips, N. G., Ackley, R., Crosson, E. R., Down, A., Hutyra, L. R., Brondfield, M., Karr, J. D., Zhao, K., and Jackson, R. B., 2013, Mapping urban pipeline leaks: Methane leaks across Boston: Environmental Pollution, v. 173, p. 1-4 Townsend-Small, A., Tyler, S. C., Pataki, D. E., Xu, X., and Christensen, L. E., 2012, Isotopic measurements of atmospheric methane in Los Angeles, California, USA: Influence of "fugitive" fossil fuel emissions: Journal of Geophysical Research: Atmospheres, v. 117, no. D7 Zazzeri, G., Lowry, D., Fisher, R., France, J., Lanoisellé, M., and Nisbet, E., 2015, Plume mapping and isotopic characterisation of anthropogenic methane sources: Atmospheric Environment, v. 110, p. 151-162

Methane-bomb natural gas

International Nuclear Information System (INIS)

Anon.

1993-01-01

About 50% of the so-called 'greenhouse-effect' is not caused by CO 2 , but by more dangerous gases, among them is methane. Natural gas consists to about 98% of methane. In Austria result about 15% of the methane emissions from offtake, storage, transport (pipelines) and distribution from natural gas. A research study of the Research Centre Seibersdorf points out that between 2.5% and 3.6% of the employed natural gas in Austria emits. The impact of this emitted methane is about 29 times worse than the impact of CO 2 (caused for examples by petroleum burning). Nevertheless the Austrian CO 2 -commission states that an increasing use of natural gas would decrease the CO 2 -emissions - but this statement is suspected to be based on wrong assumptions. (blahsl)

Methane hydrates in quaternary climate change

International Nuclear Information System (INIS)

Kennett, J. P.; Hill, T. M.; Behl, R. J.

2005-01-01

The hydrate reservoir in marine sediments is known to contain a large volume of exchangeable carbon stored as solid methane hydrate and associated free gas. This reservoir has been shown to be potentially unstable in response to changing intermediate water temperature and sea level (pressure). Evidence continues to grow for past episodes of major methane release at times of climatic warming. Yet few studies of late Quaternary climate change include methane hydrates as an integral part of the global climate system, in spite of the largest known oscillations at this time in sea level and upper ocean temperature changes for the Cenozoic or earlier, conditions that favor instability of the methane hydrate reservoir. Abrupt increases in atmospheric methane recorded in polar ice cores are widely believed to have resulted, not from ocean-floor methane degassing, but instead from continental wetland activation, a hypothesis thus far unsupported by geological data. Furthermore, as part of this Wetland Methane Hypothesis, the abrupt methane increases have been seen as a response to climatic warming rather than contributing significantly to the change. An alternative view (formulated as the Clathrate Gun Hypothesis) is that the speed, magnitude and timing of abrupt climate change in the recent geologic past are consistent with the process of major degassing of methane hydrates. We summarize aspects of this hypothesis here and needs to test this hypothesis. (Author)

Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain southeastern Australian methane emissions

Directory of Open Access Journals (Sweden)

Z. M. Loh

2015-01-01

Full Text Available This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E. The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS and the CSIRO Conformal-Cubic Atmospheric Model (CCAM. Radon is also simulated and used to reduce the impact of transport differences between the models and observations. Comparisons are made for air samples that have traversed the Australian continent. All six emission scenarios give modelled concentrations that are broadly consistent with those observed. There are three notable mismatches, however. Firstly, scenarios that incorporate interannually varying biomass burning emissions produce anomalously high methane concentrations at Cape Grim at times of large fire events in southeastern Australia, most likely due to the fire methane emissions being unrealistically input into the lowest model level. Secondly, scenarios with wetland methane emissions in the austral winter overestimate methane concentrations at Cape Grim during wintertime while scenarios without winter wetland emissions perform better. Finally, all scenarios fail to represent a~methane source in austral spring implied by the observations. It is possible that the timing of wetland emissions in the scenarios is incorrect with recent satellite measurements suggesting an austral spring (September–October–November, rather than winter, maximum for wetland emissions.

Anaerobic Oxidization of Methane in a Minerotrophic Peatland: Enrichment of Nitrite-Dependent Methane-Oxidizing Bacteria

Science.gov (United States)

Zhu, Baoli; van Dijk, Gijs; Fritz, Christian; Smolders, Alfons J. P.; Pol, Arjan; Jetten, Mike S. M.

2012-01-01

The importance of anaerobic oxidation of methane (AOM) as a methane sink in freshwater systems is largely unexplored, particularly in peat ecosystems. Nitrite-dependent anaerobic methane oxidation (n-damo) was recently discovered and reported to be catalyzed by the bacterium “Candidatus Methylomirabilis oxyfera,” which is affiliated with the NC10 phylum. So far, several “Ca. Methylomirabilis oxyfera” enrichment cultures have been obtained using a limited number of freshwater sediments or wastewater treatment sludge as the inoculum. In this study, using stable isotope measurements and porewater profiles, we investigated the potential of n-damo in a minerotrophic peatland in the south of the Netherlands that is infiltrated by nitrate-rich ground water. Methane and nitrate profiles suggested that all methane produced was oxidized before reaching the oxic layer, and NC10 bacteria could be active in the transition zone where countergradients of methane and nitrate occur. Quantitative PCR showed high NC10 bacterial cell numbers at this methane-nitrate transition zone. This soil section was used to enrich the prevalent NC10 bacteria in a continuous culture supplied with methane and nitrite at an in situ pH of 6.2. An enrichment of nitrite-reducing methanotrophic NC10 bacteria was successfully obtained. Phylogenetic analysis of retrieved 16S rRNA and pmoA genes showed that the enriched bacteria were very similar to the ones found in situ and constituted a new branch of NC10 bacteria with an identity of less than 96 and 90% to the 16S rRNA and pmoA genes of “Ca. Methylomirabilis oxyfera,” respectively. The results of this study expand our knowledge of the diversity and distribution of NC10 bacteria in the environment and highlight their potential contribution to nitrogen and methane cycles. PMID:23042166

Methanization of industrial liquid effluents

International Nuclear Information System (INIS)

Frederic, S.; Lugardon, A.

2007-01-01

In a first part, this work deals with the theoretical aspects of the methanization of the industrial effluents; the associated reactional processes are detailed. The second part presents the technological criteria for choosing the methanization process in terms of the characteristics of the effluent to be treated. Some of the methanization processes are presented with their respective advantages and disadvantages. At last, is described the implementation of an industrial methanization unit. The size and the main choices are detailed: the anaerobic reactor, the control, the valorization aspects of the biogas produced. Some examples of industrial developments illustrate the different used options. (O.M.)

Elimination of methane in exhaust gas from biogas upgrading process by immobilized methane-oxidizing bacteria.

Science.gov (United States)

Wu, Ya-Min; Yang, Jing; Fan, Xiao-Lei; Fu, Shan-Fei; Sun, Meng-Ting; Guo, Rong-Bo

2017-05-01

Biogas upgrading is essential for the comprehensive utilization of biogas as substitute of natural gas. However, the methane in the biogas can be fully recovered during the upgrading process of biogas, and the exhaust gas produced during biogas upgrading may contain a very low concentration of methane. If the exhaust gas with low concentration methane releases to atmosphere, it will be harmful to environment. In addition, the utilization of large amounts of digestate produced from biogas plant is another important issue for the development of biogas industry. In this study, solid digestate was used to produce active carbon, which was subsequently used as immobilized material for methane-oxidizing bacteria (MOB) in biofilter. Biofilter with MOB immobilized on active carbon was used to eliminate the methane in exhaust gas from biogas upgrading process. Results showed porous active carbon was successfully made from solid digestate. The final methane elimination capacity of immobilized MOB reached about 13molh -1 m -3 , which was more 4 times higher than that of MOB without immobilization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics and mechanism of methane oxidation in supercritical water

International Nuclear Information System (INIS)

Rofer, C.K.; Streit, G.E.

1988-10-01

This project, is a Hazardous Waste Remedial Actions Program (HAZWRAP) Research and Development task being carried out by the Los Alamos National Laboratory. Its objective is to achieve an understanding of the technology for use in scaling up and applying oxidation in supercritical water as a viable process for treating a variety of Department of Energy Defense Programs (DOE-DP) waste streams. This report presents experimental results for the kinetics of the oxidation of methane and methanol in supercritical water and computer modeling results for the oxidation of carbonmonoxide and methane in supercritical water. The experimental and modeling results obtained to date on these one-carbon model compounds indicate that the mechanism of oxidation in supercritical water can be represented by free-radical reactions with appropriate modifications for high pressure and the high water concentration. If these current trends are sustained, a large body of existing literature data on the kinetics of elementary reactions can be utilized to predict the behavior of other compounds and their mixtures. 7 refs., 4 figs., 3 tabs

Changes in methane oxidation activity and methanotrophic community composition in saline alkaline soils.

Science.gov (United States)

Serrano-Silva, Nancy; Valenzuela-Encinas, César; Marsch, Rodolfo; Dendooven, Luc; Alcántara-Hernández, Rocio J

2014-05-01

The soil of the former Lake Texcoco is a saline alkaline environment where anthropogenic drainage in some areas has reduced salt content and pH. Potential methane (CH4) consumption rates were measured in three soils of the former Lake Texcoco with different electrolytic conductivity (EC) and pH, i.e. Tex-S1 a >18 years drained soil (EC 0.7 dS m(-1), pH 8.5), Tex-S2 drained for ~10 years (EC 9.0 dS m(-1), pH 10.3) and the undrained Tex-S3 (EC 84.8 dS m(-1), pH 10.3). An arable soil from Alcholoya (EC 0.7 dS m(-1), pH 6.7), located nearby Lake Texcoco was used as control. Methane oxidation in the soil Tex-S1 (lowest EC and pH) was similar to that in the arable soil from Alcholoya (32.5 and 34.7 mg CH4 kg(-1) dry soil day(-1), respectively). Meanwhile, in soils Tex-S2 and Tex-S3, the potential CH4 oxidation rates were only 15.0 and 12.8 mg CH4 kg(-1) dry soil day(-1), respectively. Differences in CH4 oxidation were also related to changes in the methane-oxidizing communities in these soils. Sequence analysis of pmoA gene showed that soils differed in the identity and number of methanotrophic phylotypes. The Alcholoya soil and Tex-S1 contained phylotypes grouped within the upland soil cluster gamma and the Jasper Ridge, California JR-2 clade. In soil Tex-S3, a phylotype related to Methylomicrobium alcaliphilum was detected.

Anthropogenic CO2 in the ocean

Directory of Open Access Journals (Sweden)

Tsung-Hung Peng

2005-06-01

Full Text Available The focus of this review article is on the anthropogenic CO2 taken up by the ocean. There are several methods of identifying the anthropogenic CO2 signal and quantifying its inventory in the ocean. The ?C* method is most frequently used to estimate the global distribution of anthropogenic CO2 in the ocean. Results based on analysis of the dataset obtained from the comprehensive surveys of inorganic carbon distribution in the world oceans in the 1990s are given. These surveys were jointly conducted during the World Ocean Circulation Experiment (WOCE and the Joint Global Ocean Flux Study (JGOFS. This data set consists of 9618 hydrographic stations from a total of 95 cruises, which represents the most accurate and comprehensive view of the distribution of inorganic carbon in the global ocean available today. The increase of anthropogenic CO2 in the ocean during the past few decades is also evaluated using direct comparison of results from repeat surveys and using statistical method of Multi-parameter Linear Regression (MLR. The impact of increasing oceanic anthropogenic CO2 on the calcium carbonate system in the ocean is reviewed briefly as well. Extensive studies of CaCO3 dissolution as a result of increasing anthropogenic CO2 in the ocean have revealed several distinct oceanic regions where the CaCO3 undersaturation zone has expanded.

Evaluation of methane emissions from Taiwanese paddies

International Nuclear Information System (INIS)

Liu, C.-W.; Wu, C.-Y.

2004-01-01

The main greenhouse gases are carbon dioxide, methane and nitrous oxide. Methane is the most important because the warming effect of methane is 21 times greater than that of carbon dioxide. Methane emitted from rice paddy fields is a major source of atmospheric methane. In this work, a methane emission model (MEM), which integrates climate change, plant growth and degradation of soil organic matter, was applied to estimate the emission of methane from rice paddy fields in Taiwan. The estimated results indicate that much methane is emitted during the effective tillering and booting stages in the first crop season and during the transplanting stage in the second crop season in a year. Sensitivity analysis reveals that the temperature is the most important parameter that governs the methane emission rate. The order of the strengths of the effects of the other parameters is soil pH, soil water depth (SWD) and soil organic matter content. The masses of methane emitted from rice paddy fields of Taiwan in the first and second crop seasons are 28,507 and 350,231 tons, respectively. The amount of methane emitted during the second crop season is 12.5 times higher than that emitted in the first crop season. With a 12% reduction in planted area during the second crop season, methane emission could be reduced by 21%. In addition, removal of rice straw left from the first crop season and increasing the depth of flooding to 25 cm are also strategies that could help reduce annual emission by up to 18%

Planning and Execution of a Marine Methane Hydrate Pressure Coring Program for the Walker Ridge and Green Canyon Areas of the Gulf of Mexico

Energy Technology Data Exchange (ETDEWEB)

Humphrey, Gary [Fugro Geoconsulting Inc., Houston, TX (United States)

2015-09-14

The objective of this project (and report) is to produce a guide to developing scientific, operational, and logistical plans for a future methane hydrate-focused offshore pressure coring program. This report focuses primarily on a potential coring program in the Walker Ridge 313 and Green Canyon 955 blocks where previous investigations were undertaken as part of the 2009 Department of Energy JIP Leg II expedition, however, the approach to designing a pressure coring program that was utilized for this project may also serve as a useful model for planning pressure coring programs for hydrates in other areas. The initial portion of the report provides a brief overview of prior investigations related to gas hydrates in general and at the Walker Ridge 313 and Green Canyon 955 blocks in particular. The main content of the report provides guidance for various criteria that will come into play when designing a pressure coring program.

Wave-induced release of methane : littoral zones as a source of methane in lakes

OpenAIRE

Hofmann, Hilmar; Federwisch, Luisa; Peeters, Frank

2010-01-01

This study investigates the role of surface waves and the associated disturbance of littoral sediments for the release and later distribution of dissolved methane in lakes. Surface wave field, wave-induced currents, acoustic backscatter strength, and the concentration and distribution of dissolved methane were measured simultaneously in Lake Constance, Germany. The data indicate that surface waves enhance the release of dissolved methane in the shallow littoral zone via burst-like releases of...

Direct Activation Of Methane

KAUST Repository

Basset, Jean-Marie; Sun, Miao; Caps, Valerie; Pelletier, Jeremie; Abou-Hamad, Edy

2013-01-01

Heteropolyacids (HPAs) can activate methane at ambient temperature (e.g., 20.degree. C.) and atmospheric pressure, and transform methane to acetic acid, in the absence of any noble metal such as Pd). The HPAs can be, for example, those with Keggin

Methane emissions from coal mining

International Nuclear Information System (INIS)

Boyer, C.M.; Kelafant, J.R.; Kuuskraa, V.A.; Manger, K.C.; Kruger, D.

1990-09-01

The report estimates global methane emissions from coal mining on a country specific basis, evaluates the technologies available to degasify coal seams and assesses the economics of recovering methane liberated during mining. 33 to 64 million tonnes were liberated in 1987 from coal mining, 75 per cent of which came from China, the USSR, Poland and the USA. Methane emissions from coal mining are likely to increase. Emission levels vary between surface and underground mines. The methane currently removed from underground mines for safety reasons could be used in a number of ways, which may be economically attractive. 55 refs., 19 figs., 24 tabs

Airborne Quantification of Methane Emissions in the San Francisco Bay Area of California

Science.gov (United States)

Guha, A.; Newman, S.; Martien, P. T.; Young, A.; Hilken, H.; Faloona, I. C.; Conley, S.

2017-12-01

The Bay Area Air Quality Management District, the San Francisco Bay Area's air quality regulatory agency, has set a goal to reduce the region's greenhouse gas (GHG) emissions 80% below 1990 levels by 2050, consistent with the State of California's climate protection goal. The Air District maintains a regional GHG emissions inventory that includes emissions estimates and projections which influence the agency's programs and regulatory activities. The Air District is currently working to better characterize methane emissions in the GHG inventory through source-specific measurements, to resolve differences between top-down regional estimates (Fairley and Fischer, 2015; Jeong et al., 2016) and the bottom-up inventory. The Air District funded and participated in a study in Fall 2016 to quantify methane emissions from a variety of sources from an instrumented Mooney aircraft. This study included 40 hours of cylindrical vertical profile flights that combined methane and wind measurements to derive mass emission rates. Simultaneous measurements of ethane provided source-apportionment between fossil-based and biological methane sources. The facilities sampled included all five refineries in the region, five landfills, two dairy farms and three wastewater treatment plants. The calculated mass emission rates were compared to bottom-up rates generated by the Air District and to those from facility reports to the US EPA as part of the mandatory GHG reporting program. Carbon dioxide emission rates from refineries are found to be similar to bottom-up estimates for all sources, supporting the efficacy of the airborne measurement methodology. However, methane emission estimates from the airborne method showed significant differences for some source categories. For example, methane emission estimates based on airborne measurements were up to an order of magnitude higher for refineries, and up to five times higher for landfills compared to bottom-up methods, suggesting significant

Gas-liquid equilibrium in mixtures of methane + m-xylene, and methane + m-cresol

Energy Technology Data Exchange (ETDEWEB)

Simnick, J J; Sebastian, H M; Lin, H M; Chao, K C

1979-01-01

Compositions of saturated equilibrium liquid and vapor phases as determined in a flow apparatus for methane + m-xylene mixtures at 370/sup 0/, 450/sup 0/, 520/sup 0/, and 600/sup 0/F (190/sup 0/, 230/sup 0/, 270/sup 0/, and 310/sup 0/C) and up to 200 atm, and for methane + m-cresol at 370/sup 0/, 520/sup 0/, 660/sup 0/, and 730/sup 0/F (190/sup 0/, 270/sup 0/, 350/sup 0/, and 390/sup 0/C) and up to 250 atm. Compared with published data on its solubility in benzene, methane appears to be more soluble in m-xylene at similar conditions but substantially less soluble in m-cresol. This difference indicates that the functional groups CH/sub 3/ and OH play different roles in determining the solubility of methane.

Electrocatalytic oxidation of methane: investigations of new catalysts to be used in a solid polymer electrolyte methane fuel-cell; Oxydation electrocatalytique du methane: recherche de catalyseurs en vue d'une application a une pile au methane a electrolyte polymere solide

Energy Technology Data Exchange (ETDEWEB)

Berthelot, S

1998-07-01

This thesis evaluated the performances of many catalysts facing the methane oxidation which is a critical step in methane fuel cells development. In a first part the study of the methane electro-oxidation has been realized by classical electrochemical technics on many electrodes to determine the most active ones. In a second part the in situ reflection infra-red spectroscopy allowed to identify, during the methane oxidation, the adsorbed species on the electrode and the reaction products. These results also help the understanding of the part of the concerned materials mechanisms in the methane oxidation and then to optimize them for a whole oxidation of the methane in carbon dioxide. The final objective is the use of the methane in a PEMFC fuel cell type. A comparison with the methanol and C2 hydrocarbons behaviour, such as the ethane the ethylene and the acetylene, has been done to evaluate the performances. (A.L.B.)

Ebullitive methane emissions from oxygenated wetland streams

Science.gov (United States)

Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

2014-01-01

Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

Methane generated from graphite--tritium interaction

International Nuclear Information System (INIS)

Coffin, D.O.; Walthers, C.R.

1979-01-01

When hydrogen isotopes are separated by cryogenic distillation, as little as 1 ppM of methane will eventually plug the still as frost accumulates on the column packings. Elemental carbon exposed to tritium generates methane spontaneously, and yet some dry transfer pumps, otherwise compatible with tritium, convey the gas with graphite rotors. This study was to determine the methane production rate for graphite in tritium. A pump manufacturer supplied graphite samples that we exposed to tritium gas at 0.8 atm. After 137 days we measured a methane synthesis rate of 6 ng/h per cm 2 of graphite exposed. At this rate methane might grow to a concentration of 0.01 ppM when pure tritium is transferred once through a typical graphite--rotor transfer pump. Such a low methane level will not cause column blockage, even if the cryogenic still is operated continuously for many years

Adsorption and methanation of carbon dioxide on a nickel/silica catalyst

Energy Technology Data Exchange (ETDEWEB)

Falconer, J.L.; Zagli, A.E.

1980-04-01

Temperature-programed desorption and reaction studies showed that increasing amounts of CO/sub 2/ adsorbed on silica-supported 6.9% nickel with increasing temperature to a maximum adsorption at approx. 443/sup 0/K, i.e., that the adsorption was activated; that CO/sub 2/ desorbed partly as CO/sub 2/ with the peak at 543/sup 0/K, and partly as CO with several peaks; that in the presence of hydrogen, nearly all adsorbed CO/sub 2/ desorbed as methane, and a small amount as CO; and that the methane desorption peaks from adsorbed CO and CO/sub 2/ both occurred at 473/sup 0/K. These results suggested that carbon dioxide adsorbed dissociatively as a carbon monoxide and an oxygen species. An observed absence of higher hydrocarbons in the methanation products of carbon dioxide was attributed to a high hydrogen/carbon monoxide surface ratio caused by the activated carbon dioxide adsorption.

Methane emissions from MBT landfills

Energy Technology Data Exchange (ETDEWEB)

Heyer, K.-U., E-mail: heyer@ifas-hamburg.de; Hupe, K.; Stegmann, R.

2013-09-15

Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m{sup 3} CH{sub 4}/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH{sub 4}/(m{sup 2} h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD

Methane Flux and Authigenic Carbonate in Shallow Sediments Overlying Methane Hydrate Bearing Strata in Alaminos Canyon, Gulf of Mexico

Directory of Open Access Journals (Sweden)

Joseph P. Smith

2014-09-01

Full Text Available In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and dissolved inorganic carbon (DIC concentrations in porewaters, headspace methane, and solid phase carbonate concentrations were measured at each core location to investigate the cycling of methane-derived carbon in shallow sediments overlying the hydrate bearing strata. When integrated with stable carbon isotope ratios of DIC, geochemical results suggest a significant fraction of the methane flux at this site is cycled into the inorganic carbon pool. The incorporation of methane-derived carbon into dissolved and solid inorganic carbon phases represents a significant sink in local carbon cycling and plays a role in regulating the flux of methane to the overlying water column at Alaminos Canyon. Targeted, high-resolution geochemical characterization of the biogeochemical cycling of methane-derived carbon in shallow sediments overlying hydrate bearing strata like those in Alaminos Canyon is critical to quantifying methane flux and estimating methane hydrate distributions in gas hydrate bearing marine sediments.

Estimating animal mortality from anthropogenic hazards

Science.gov (United States)

Carcass searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. Para...

How Much Can Non-industry Standard Measurement Methodologies Benefit Methane Reduction Programs?

Science.gov (United States)

Risk, D. A.; O'Connell, L.; Atherton, E.

2017-12-01

In recent years, energy sector methane emissions have been recorded in large part by applying modern non-industry-standard techniques. Industry may lack the regulatory flexibility to use such techniques, or in some cases may not understand the possible associated economic advantage. As progressive jurisdictions move from estimation and towards routine measurement, the research community should provide guidance to help regulators and companies measure more effectively, and economically if possible. In this study, we outline a modelling experiment in which we explore the integration of non-industry-standard measurement techniques as part of a generalized compliance measurement program. The study was not intended to be exhaustive, or to recommend particular combinations, but instead to explore the inter-relationships between methodologies, development type, compliance practice. We first defined the role, applicable scale, detection limits, working distances, and approximate deployment cost of several measurement methodologies. We then considered a variety of development types differing mainly in footprint, density, and emissions "profile". Using a Monte Carlo approach, we evaluated the effect of these various factors on the cost and confidence of the compliance measurement program. We found that when added individually, some of the research techniques were indeed able to deliver an improvement in cost and/or confidence when used alongside industry-standard Optical Gas Imaging. When applied in combination, the ideal fraction of each measurement technique depended on development type, emission profile, and whether confidence or cost was more important. Results suggest that measurement cost and confidence could be improved if energy companies exploited a wider range of measurement techniques, and in a manner tailored to each development. In the short-term, combining clear scientific guidance with economic information could benefit immediate mitigation efforts over

Evidence for methane in Martian meteorites.

Science.gov (United States)

Blamey, Nigel J F; Parnell, John; McMahon, Sean; Mark, Darren F; Tomkinson, Tim; Lee, Martin; Shivak, Jared; Izawa, Matthew R M; Banerjee, Neil R; Flemming, Roberta L

2015-06-16

The putative occurrence of methane in the Martian atmosphere has had a major influence on the exploration of Mars, especially by the implication of active biology. The occurrence has not been borne out by measurements of atmosphere by the MSL rover Curiosity but, as on Earth, methane on Mars is most likely in the subsurface of the crust. Serpentinization of olivine-bearing rocks, to yield hydrogen that may further react with carbon-bearing species, has been widely invoked as a source of methane on Mars, but this possibility has not hitherto been tested. Here we show that some Martian meteorites, representing basic igneous rocks, liberate a methane-rich volatile component on crushing. The occurrence of methane in Martian rock samples adds strong weight to models whereby any life on Mars is/was likely to be resident in a subsurface habitat, where methane could be a source of energy and carbon for microbial activity.

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

Science.gov (United States)

Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin; Schink, Bernhard

2014-01-01

Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were very abundant at deep-water sites (profundal sediment). In profundal sediment, the vertical distribution of M. oxyfera-like bacteria showed a distinct peak in anoxic layers that coincided with the zone of methane oxidation and nitrate consumption, a strong indication for n-damo carried out by M. oxyfera-like bacteria. Both potential n-damo rates calculated from cell densities (660–4,890 µmol CH4⋅m−2⋅d−1) and actual rates calculated from microsensor profiles (31–437 µmol CH4⋅m−2⋅d−1) were sufficiently high to prevent methane release from profundal sediment solely by this process. Additionally, when nitrate was added to sediment cores exposed to anoxic conditions, the n-damo zone reestablished well below the sediment surface, completely preventing methane release from the sediment. We conclude that the previously overlooked n-damo process can be the major methane sink in stable freshwater environments if nitrate is available in anoxic zones. PMID:25472842

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake.

Science.gov (United States)

Deutzmann, Joerg S; Stief, Peter; Brandes, Josephin; Schink, Bernhard

2014-12-23

Anaerobic methane oxidation coupled to denitrification, also known as "nitrate/nitrite-dependent anaerobic methane oxidation" (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were very abundant at deep-water sites (profundal sediment). In profundal sediment, the vertical distribution of M. oxyfera-like bacteria showed a distinct peak in anoxic layers that coincided with the zone of methane oxidation and nitrate consumption, a strong indication for n-damo carried out by M. oxyfera-like bacteria. Both potential n-damo rates calculated from cell densities (660-4,890 µmol CH4⋅m(-2)⋅d(-1)) and actual rates calculated from microsensor profiles (31-437 µmol CH4⋅m(-2)⋅d(-1)) were sufficiently high to prevent methane release from profundal sediment solely by this process. Additionally, when nitrate was added to sediment cores exposed to anoxic conditions, the n-damo zone reestablished well below the sediment surface, completely preventing methane release from the sediment. We conclude that the previously overlooked n-damo process can be the major methane sink in stable freshwater environments if nitrate is available in anoxic zones.

46 CFR 154.703 - Methane (LNG).

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Methane (LNG). 154.703 Section 154.703 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... and Temperature Control § 154.703 Methane (LNG). Unless a cargo tank carrying methane (LNG) can...

Climate forcing by anthropogenic aerosols

Energy Technology Data Exchange (ETDEWEB)

Charlson, R J; Schwartz, S E; Hales, J M; Cess, R D; Coakley, Jr, J A; Hansen, J E; Hofmann, D J [University of Washington, Seattle, WA (USA). Inst. for Environmental Studies, Dept. of Atmospheric Sciences

1992-01-24

Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of short wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square metre, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes. 73 refs., 4 figs., 2 tabs.

Climate forcing by anthropogenic aerosols.

Science.gov (United States)

Charlson, R J; Schwartz, S E; Hales, J M; Cess, R D; Coakley, J A; Hansen, J E; Hofmann, D J

1992-01-24

Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of shortwavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

Fugitive Methane Emission Identification and Source Attribution: Ethane-to-Methane Analysis Using a Portable Cavity Ring-Down Spectroscopy Analyzer

Science.gov (United States)

Kim-Hak, D.; Fleck, D.

2017-12-01

Natural gas analysis and methane specifically have become increasingly important by virtue of methane's 28-36x greenhouse warming potential compared to CO2 and accounting for 10% of total greenhouse gas emissions in the US alone. Additionally, large uncontrolled leaks, such as the recent one from Aliso Canyon in Southern California, originating from uncapped wells, storage facilities and coal mines have increased the total global contribution of methane missions even further. Determining the specific fingerprint of methane sources by quantifying the ethane to methane (C2:C1) ratios provides us with means to understand processes yielding methane and allows for sources of methane to be mapped and classified through these processes; i.e. biogenic or thermogenic, oil vs. gas vs. coal gas-related. Here we present data obtained using a portable cavity ring-down spectrometry analyzer weighing less than 25 lbs and consuming less than 35W that simultaneously measures methane and ethane in real-time with a raw 1-σ precision of plane gas propagation.

Mechanistic insights into heterogeneous methane activation

International Nuclear Information System (INIS)

Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin; Yoo, Jong Suk; Kulkarni, Ambarish

2017-01-01

While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model to aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.

Supported Catalysts for CO2 Methanation: A Review

Directory of Open Access Journals (Sweden)

Patrizia Frontera

2017-02-01

Full Text Available CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

Methane flux from boreal peatlands

International Nuclear Information System (INIS)

Crill, P.; Bartlett, K.; Roulet, N.

1992-01-01

The peatlands in the boreal zone (roughly 45 deg - 60 degN) store a significant reservoir of carbon, much of which is potentially available for exchange with the atmosphere. The anaerobic conditions that cause these soils to accumulate carbon also makes wet, boreal peatlands significant sources of methane to the global troposphere. It is estimated that boreal wetlands contribute approximately 19.5 Tg methane per year. The data available on the magnitude of boreal methane emissions have rapidly accumulated in the past twenty years. This paper offers a short review of the flux measured (with range roughly 1 - 2000 mg methane/m2d), considers environmental controls of the flux and briefly discusses how climate change might affect future fluxes

Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

Energy Technology Data Exchange (ETDEWEB)

Akamatsu, Fumikazu, E-mail: f-akamt55@pwri.go.jp [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Toda, Hideshige [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

2011-05-15

Stable nitrogen isotopic composition ({delta}{sup 15}N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in {delta}{sup 15}N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider {delta}{sup 15}N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: > {delta}{sup 15}N of aquatic insects increases downstream with anthropogenic nitrogen inputs. > {delta}{sup 15}N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. > The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

International Nuclear Information System (INIS)

Akamatsu, Fumikazu; Toda, Hideshige

2011-01-01

Stable nitrogen isotopic composition (δ 15 N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ 15 N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ 15 N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ 15 N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ 15 N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 1: EXECUTIVE SUMMARY

Science.gov (United States)

The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

Biochemically enhanced methane production from coal

Science.gov (United States)

Opara, Aleksandra

For many years, biogas was connected mostly with the organic matter decomposition in shallow sediments (e.g., wetlands, landfill gas, etc.). Recently, it has been realized that biogenic methane production is ongoing in many hydrocarbon reservoirs. This research examined microbial methane and carbon dioxide generation from coal. As original contributions methane production from various coal materials was examined in classical and electro-biochemical bench-scale reactors using unique, developed facultative microbial consortia that generate methane under anaerobic conditions. Facultative methanogenic populations are important as all known methanogens are strict anaerobes and their application outside laboratory would be problematic. Additional testing examined the influence of environmental conditions, such as pH, salinity, and nutrient amendments on methane and carbon dioxide generation. In 44-day ex-situ bench-scale batch bioreactor tests, up to 300,000 and 250,000 ppm methane was generated from bituminous coal and bituminous coal waste respectively, a significant improvement over 20-40 ppm methane generated from control samples. Chemical degradation of complex hydrocarbons using environmentally benign reagents, prior to microbial biodegradation and methanogenesis, resulted in dissolution of up to 5% bituminous coal and bituminous coal waste and up to 25% lignite in samples tested. Research results confirm that coal waste may be a significant underutilized resource that could be converted to useful fuel. Rapid acidification of lignite samples resulted in low pH (below 4.0), regardless of chemical pretreatment applied, and did not generate significant methane amounts. These results confirmed the importance of monitoring and adjusting in situ and ex situ environmental conditions during methane production. A patented Electro-Biochemical Reactor technology was used to supply electrons and electron acceptor environments, but appeared to influence methane generation in a

Methane and Climate Change

NARCIS (Netherlands)

Reay, D.; Smith, P.; Amstel, van A.R.

2010-01-01

Methane is a powerful greenhouse gas and is estimated to be responsible for approximately one-fifth of man-made global warming. Per kilogram, it is 25 times more powerful than carbon dioxide over a 100-year time horizon -- and global warming is likely to enhance methane release from a number of

Small Molecule Catalysts for Harvesting Methane Gas

Energy Technology Data Exchange (ETDEWEB)

Baker, S. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ceron-Hernandez, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oakdale, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lau, E. Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-12-06

As the average temperature of the earth increases the impact of these changes are becoming apparent. One of the most dramatic changes to the environment is the melting of arctic permafrost. The disappearance of the permafrost has resulted in release of streams of methane that was trapped in remote areas as gas hydrates in ice. Additionally, the use of fracking has also increased emission of methane. Currently, the methane is either lost to the atmosphere or flared. If these streams of methane could be brought to market, this would be an abundant source of revenue. A cheap conversion of gaseous methane to a more convenient form for transport would be necessary to economical. Conversion of methane is a difficult reaction since the C-H bond is very stable (104 kcal/mole). At the industrial scale, the Fischer-Tropsch reaction can be used to convert gaseous methane to liquid methanol but is this method is impractical for these streams that have low pressures and are located in remote areas. Additionally, the Fischer-Tropsch reaction results in over oxidation of the methane leading to many products that would need to be separated.

Methane-induced Activation Mechanism of Fused Ferric Oxide-Alumina Catalysts during Methane Decomposition

KAUST Repository

Reddy Enakonda, Linga; Zhou, Lu; Saih, Youssef; Ould-Chikh, Samy; Lopatin, Sergei; Gary, Daniel; Del-Gallo, Pascal; Basset, Jean-Marie

2016-01-01

Activation of Fe2O3-Al2O3 with CH4 (instead of H2) is a meaningful method to achieve catalytic methane decomposition (CMD). This reaction of CMD is more economic and simple against commercial methane steam reforming (MSR) as it produces COx-free H2

Constraining the relationships between anaerobic oxidation of methane and sulfate reduction under in situ methane concentrations

Science.gov (United States)

Zhuang, G.; Wegener, G.; Joye, S. B.

2017-12-01

The anaerobic oxidation of methane (AOM) is an important microbial metabolism in the global carbon cycle. In marine methane seeps sediment, this process is mediated by syntrophic consortium that includes anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Stoichiometrically in AOM methane oxidation should be coupled to sulfate reduction (SR) in a 1:1 ratio. However, weak coupling of AOM and SR in seep sediments was frequently observed from the ex situ rate measurements, and the metabolic dynamics of AOM and SR under in situ conditions remain poorly understood. Here we investigated the metabolic activity of AOM and SR with radiotracers by restoring in situ methane concentrations under pressure to constrain the in situ relationships between AOM and SR in the cold seep sediments of Gulf of Mexico as well as the sediment-free AOM enrichments cultivated from cold seep of Italian Island Elba or hydrothermal vent of Guaymas Basin5. Surprisingly, we found that AOM rates strongly exceeded those of SR when high pressures and methane concentrations were applied at seep sites of GC600 and GC767 in Gulf of Mexico. With the addition of molybdate, SR was inhibited but AOM was not affected, suggesting the potential coupling of AOM with other terminal processes. Amendments of nitrate, iron, manganese and AQDS to the SR-inhibited slurries did not stimulate or inhibit the AOM activity, indicating either those electron acceptors were not limiting for AOM in the sediments or AOM was coupled to other process (e.g., organic matter). In the ANME enrichments, higher AOM rates were also observed with the addition of high concentrations of methane (10mM and 50 mM). The tracer transfer of CO2 to methane, i.e., the back reaction of AOM, increased with increasing methane concentrations and accounted for 1%-5% of the AOM rates. AOM rates at 10 mM and 50 mM methane concentration were much higher than the SR rates, suggesting those two processes were not tightly coupled

Methane and nitrous oxide: Methods in national emissions inventories and options for control

Energy Technology Data Exchange (ETDEWEB)

Van Amstel, A.R. (ed.)

1993-07-01

The UN Framework Convention on Climate Change signed in Rio de Janeiro, Brazil, calls for the return of anthropogenic emissions of greenhouse gases to their 1990 levels by the year 2000 in industrialized countries. It also calls for a monitoring of the emissions of greenhouse gases. It is important that reliable and scientifically credible national inventories are available for the international negotiations. Therefore a consistent methodology and a transparent reporting format is needed. The title workshop had two main objectives: (1) to support the development a methodology and format for national emissions inventories of greenhouse gases by mid 1993, as coordinated by the Science Working Group of the IPCC and the OECD; and (2) the development of technical options for reduction of greenhouse gases and the assessment of the socio-economic feasibility of these options. The workshop consisted of key note overview presentations, and two rounds of working group sessions, each covering five parallel sessions on selected sources. In the first round of each working group session the literature, existing methods for methane and nitrous oxide inventories, and the OECD/IPCC guidelines have been addressed. Then, in the second round, options for emission reductions have been discussed, as well as their socio-economic implications. The methane sources discussed concern oil and gas, coal mining, ruminants, animal waste, landfills and sewage treatment, combustion and industry, rice production and wetlands, biomass burning. The nitrous oxide sources discussed are agricultural soils and combustion and industry. The proceedings on methane comprise 16 introductory papers and 7 papers on the results of the working groups, while in part two four introductory papers and two papers on the results of working groups on nitrous oxide are presented. In part three future emission reduction policy options are discussed. Finally, 16 poster contributions are included

Wood to Bio-Methane demonstration project in the Netherlands

Energy Technology Data Exchange (ETDEWEB)

Van der Meijden, C.M.; Van der Drift, A.; Rietveld, G. [ECN Biomass and Energy Efficiency, Petten (Netherlands); Koenemann, J.W. [Dahlman Renewable Technology, P.O. Box 438, 3140 AK Maassluis (Netherlands); Sierhuis, W. [HVCgroup, P.O. Box 9199, 1800 GD, Alkmaar (Netherlands)

2013-06-15

The Energy research Centre of the Netherlands (ECN) has developed a biomass gasification technology, called the MILENA technology. The Milena gasification technology has a high cold gas efficiency and high methane yield, making it very suitable for gas engine and turbine applications as well as upgrading of the gas into Bio-Methane. An overall efficiency from biomass to power of over 30% is possible, whereas 70% efficiency is achievable from biomass to gas grid quality methane. HVC Group (situated in Alkmaar, North Holland) is a modern public service waste company. HVC converts waste streams which cannot be recycled into usable forms of energy. HVC has a 75 MWth waste wood boiler in operation which produces heat and electricity, and an anaerobic digester which converts domestic fruit, vegetable and garden waste into Bio-Methane. HVC expects an important role for Bio-Methane in the future and HVC has decided to join ECN with the development, demonstration and implementation of the MILENA Bio-Methane technology. Linked to the Bio-Methane demonstration project is the Netherlands Expertise Centre for Biomass Gasification. The MILENA demonstration project and the Gasification Expert Centre are supported by the following companies and organizations: HVC, TAQA, Gasunie, Dahlman, province of North Holland, the Alkmaar municipality and ECN. In 2010 and 2012 extensive lab-scale and pilot scale tests have been executed by ECN and HVC to proof that the gasification and gas cleaning technology is ready for commercial application. The final step in this test program was a duration test in the 800 kWth MILENA pilot plant coupled to the OLGA tar removal unit. The goal was to show high availability. The result of the test was an availability of the gasifier of 96% and an overall availability (including gas cooling and gas cleaning) of 85%. The results of the duration tests convinced HVC and the other partners that the technology is ready for scale-up. The results produced in the

Two-Dimensional Layered Double Hydroxides for Reactions of Methanation and Methane Reforming in C1 Chemistry.

Science.gov (United States)

Li, Panpan; Yu, Feng; Altaf, Naveed; Zhu, Mingyuan; Li, Jiangbing; Dai, Bin; Wang, Qiang

2018-01-31

CH₄ as the paramount ingredient of natural gas plays an eminent role in C1 chemistry. CH₄ catalytically converted to syngas is a significant route to transmute methane into high value-added chemicals. Moreover, the CO/CO₂ methanation reaction is one of the potent technologies for CO₂ valorization and the coal-derived natural gas production process. Due to the high thermal stability and high extent of dispersion of metallic particles, two-dimensional mixed metal oxides through calcined layered double hydroxides (LDHs) precursors are considered as the suitable supports or catalysts for both the reaction of methanation and methane reforming. The LDHs displayed compositional flexibility, small crystal sizes, high surface area and excellent basic properties. In this paper, we review previous works of LDHs applied in the reaction of both methanation and methane reforming, focus on the LDH-derived catalysts, which exhibit better catalytic performance and thermal stability than conventional catalysts prepared by impregnation method and also discuss the anti-coke ability and anti-sintering ability of LDH-derived catalysts. We believe that LDH-derived catalysts are promising materials in the heterogeneous catalytic field and provide new insight for the design of advance LDH-derived catalysts worthy of future research.

Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

DEFF Research Database (Denmark)

Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin

2014-01-01

Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments......, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques...... in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were...

Geologic Emissions of Methane and C2 - C5 Alkanes at the La Brea Tar Pits, Los Angeles, CA

Science.gov (United States)

Doezema, L. A.; Etiope, G.; Pacheco, C.

2017-12-01

Natural hydrocarbon (oil and gas) seeps are widespread in Los Angeles due to gas migration, along faults, from numerous subsurface petroleum fields. These seeps may represent important natural contributors of methane (CH4) and heavier alkanes (C2-C4) for the atmosphere. Methane flux measurements were made from various locations at the La Brea Tar Pits in Los Angeles, CA. Measurements were made using a closed-chamber method and spectroscopic sensors for CH4 and CO2, at 26 oil-asphalt seeps and 188 other sites, without gas manifestations, homogeneously distributed throughout the park. The molecular C1 - C5 composition of gas released from seeps and soil was also analyzed using either FTIR spectroscopy or gas chromatography (GC-FID). Methane emissions from seeps varied from approximately 7 to 54,000 g m-2 day-1, while emissions from soil degassing were between 0 and 9,000 g m-2 day-1. Total emissions were estimated to be in the order of 103 kg day-1 for methane, and at least 10 and 5 kg day-1 for ethane and propane, respectively. The seeping gas exhibited high C1/(C2 + C3) ratios, likely due to molecular fractionation during gas migration from a subsurface petroleum reservoir. Evidence for biodegredation in certain samples was indicated by large i-butane to n-butane ratios. These molecular alterations can be important tracers of natural seepage and should be considered in the atmospheric modelling of the relative contribution of fossil fuel (anthropogenic fugitive emission and natural geologic sources) vs biogenic sources, on local and global scales.

Variability and quasi-decadal changes in the methane budget over the period 2000-2012

Science.gov (United States)

Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon-Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean-François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans-Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; Weiss, Ray; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

2017-09-01

Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH4) budget over 2000-2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry), inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000-2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000-2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008-2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16-32] Tg CH4 yr-1 higher methane emissions over the period 2008-2012 compared to 2002-2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002-2006 and 2008-2012 differs from one atmospheric inversion study to another. However, all top-down studies

Is Optical Gas Imaging Effective for Detecting Fugitive Methane Emissions? - A Technological and Policy Perspective

Science.gov (United States)

Ravikumar, A. P.; Wang, J.; Brandt, A. R.

2016-12-01

Mitigating fugitive methane emissions from the oil and gas industry has become an important concern for both businesses and regulators. While recent studies have improved our understanding of emissions from all sectors of the natural gas supply chain, cost-effectively identifying leaks over expansive natural gas infrastructure remains a significant challenge. Recently, the Environmental Protection Agency (EPA) has recommended the use of optical gas imaging (OGI) technologies to be used in industry-wide leak detection and repair (LDAR) programs. However, there has been little to no systematic study of the effectiveness of infrared-camera-based OGI technology for leak detection applications. Here, we develop a physics-based model that simulates a passive infrared camera imaging a methane leak against varying background and ambient conditions. We verify the simulation tool through a series of large-volume controlled release field experiments wherein known quantities of methane were released and imaged from a range of distances. After simulator verification, we analyze the effects of environmental conditions like temperature, wind, and imaging background on the amount of methane detected from a statistically representative survey program. We also examine the effects of LDAR design parameters like imaging distance, leak size distribution, and gas composition. We show that imaging distance strongly affects leak detection - EPA's expectation of a 60% reduction in fugitive emissions based on a semi-annual LDAR survey will be realized only if leaks are imaged at a distance less than 10 m from the source under ideal environmental conditions. Local wind speed is also shown to be important. We show that minimum detection limits are 3 to 4 times higher for wet-gas compositions that contain a significant fraction of ethane and propane, resulting a significantly large leakage rate. We also explore the importance of `super-emitters' on the performance of an OGI-based leak

Enteric Methane Emission from Pigs

DEFF Research Database (Denmark)

Jørgensen, Henry; Theil, Peter Kappel; Knudsen, Knud Erik Bach

2011-01-01

per kg meat produced is increased (Fernández et al. 1983; Lekule et al. 1990). The present chapter will summarise our current knowledge concerning dietary and enteric fermentation that may influence the methane (CH4) emission in pigs. Enteric fermentation is the digestive process by which.......3 % of the worlds pig population. The main number of pigs is in Asia (59.6 %) where the main pig population stay in China (47.8 % of the worlds pig population). The objective of the chapter is therefore: To obtain a general overview of the pigs’ contribution to methane emission. Where is the pigs’ enteric gas...... produced and how is it measured. The variation in methane emission and factors affecting the emission. Possibility for reducing the enteric methane emission and the consequences....

Catalytic aromatization of methane.

Science.gov (United States)

Spivey, James J; Hutchings, Graham

2014-02-07

Recent developments in natural gas production technology have led to lower prices for methane and renewed interest in converting methane to higher value products. Processes such as those based on syngas from methane reforming are being investigated. Another option is methane aromatization, which produces benzene and hydrogen: 6CH4(g) → C6H6(g) + 9H2(g) ΔG°(r) = +433 kJ mol(-1) ΔH°(r) = +531 kJ mol(-1). Thermodynamic calculations for this reaction show that benzene formation is insignificant below ∼600 °C, and that the formation of solid carbon [C(s)] is thermodynamically favored at temperatures above ∼300 °C. Benzene formation is insignificant at all temperatures up to 1000 °C when C(s) is included in the calculation of equilibrium composition. Interestingly, the thermodynamic limitation on benzene formation can be minimized by the addition of alkanes/alkenes to the methane feed. By far the most widely studied catalysts for this reaction are Mo/HZSM-5 and Mo/MCM-22. Benzene selectivities are generally between 60 and 80% at methane conversions of ∼10%, corresponding to net benzene yields of less than 10%. Major byproducts include lower molecular weight hydrocarbons and higher molecular weight substituted aromatics. However, carbon formation is inevitable, but the experimental findings show this can be kinetically limited by the use of H2 or oxidants in the feed, including CO2 or steam. A number of reactor configurations involving regeneration of the carbon-containing catalyst have been developed with the goal of minimizing the cost of regeneration of the catalyst once deactivated by carbon deposition. In this tutorial review we discuss the thermodynamics of this process, the catalysts used and the potential reactor configurations that can be applied.

Direct Aromaization of Methane

Energy Technology Data Exchange (ETDEWEB)

George Marcelin

1997-01-15

The thermal decomposition of methane offers significant potential as a means of producing higher unsaturated and aromatic hydrocarbons when the extent of reaction is limited. Work in the literature previous to this project had shown that cooling the product and reacting gases as the reaction proceeds would significantly reduce or eliminate the formation of solid carbon or heavier (Clo+) materials. This project studied the effect and optimization of the quenching process as a means of increasing the amount of value added products during the pyrolysis of methane. A reactor was designed to rapidly quench the free-radical combustion reaction so as to maximize the yield of aromatics. The use of free-radical generators and catalysts were studied as a means of lowering the reaction temperature. A lower reaction temperature would have the benefits of more rapid quenching as well as a more feasible commercial process due to savings realized in energy and material of construction costs. It was the goal of the project to identify promising routes from methane to higher hydrocarbons based on the pyrolysis of methane.

Agricultural methanization

International Nuclear Information System (INIS)

2011-01-01

After having briefly outlined the interest of the development of methanization of agricultural by-products in the context of struggle against climate change, and noticed that France is only now developing this sector as some other countries already did, this publication describes the methanization process also called anaerobic digestion, which produces a digestate and biogas. Advantages for the agriculture sector are outlined, as well as drawbacks and recommendations (required specific technical abilities, an attention to the use of energetic crops, an improved economic balance which still depends on public subsidies, competition in the field of waste processing). Actions undertaken by the ADEME are briefly evoked

Low-Altitude Aerial Methane Concentration Mapping

Directory of Open Access Journals (Sweden)

Bara J. Emran

2017-08-01

Full Text Available Detection of leaks of fugitive greenhouse gases (GHGs from landfills and natural gas infrastructure is critical for not only their safe operation but also for protecting the environment. Current inspection practices involve moving a methane detector within the target area by a person or vehicle. This procedure is dangerous, time consuming, labor intensive and above all unavailable when access to the desired area is limited. Remote sensing by an unmanned aerial vehicle (UAV equipped with a methane detector is a cost-effective and fast method for methane detection and monitoring, especially for vast and remote areas. This paper describes the integration of an off-the-shelf laser-based methane detector into a multi-rotor UAV and demonstrates its efficacy in generating an aerial methane concentration map of a landfill. The UAV flies a preset flight path measuring methane concentrations in a vertical air column between the UAV and the ground surface. Measurements were taken at 10 Hz giving a typical distance between measurements of 0.2 m when flying at 2 m/s. The UAV was set to fly at 25 to 30 m above the ground. We conclude that besides its utility in landfill monitoring, the proposed method is ready for other environmental applications as well as the inspection of natural gas infrastructure that can release methane with much higher concentrations.

Anthropogenic Space Weather

Science.gov (United States)

Gombosi, T. I.; Baker, D. N.; Balogh, A.; Erickson, P. J.; Huba, J. D.; Lanzerotti, L. J.

2017-11-01

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release experiments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.

Reconstructing Methane Emission Events in the Arctic Ocean: Observations from the Past to Present

Science.gov (United States)

Panieri, G.; Mienert, J.; Fornari, D. J.; Torres, M. E.; Lepland, A.

2015-12-01

Methane hydrates are ice-like crystals that are present along continental margins, occurring in the pore space of deep sediments or as massive blocks near the seafloor. They form in high pressure and low temperature environments constrained by thermodynamic stability, and supply of methane. In the Arctic, gas hydrates are abundant, and the methane released by their destabilization can affect local to global carbon budgets and cycles, ocean acidification, and benthic community survival. With the aim to locate in space and time the periodicity of methane venting, CAGE is engaged in a vast research program in the Arctic, a component of which comprises the analyses of numerous sediment cores and correlative geophysical and geochemical data from different areas. Here we present results from combined analyses of biogenic carbonate archives along the western Svalbard Margin, which reveal past methane venting events in this region. The reconstruction of paleo-methane discharge is complicated by precipitation of secondary carbonate on foraminifera shells, driven by an increase in alkalinity during anaerobic oxidation of methane (AOM). The biogeochemical processes involved in methane cycling and processes that drive methane migration affect the depth where AOM occurs, with relevance to secondary carbonate formation. Our results show the value and complexity of separating primary vs. secondary signals in bioarchives with relevance to understanding fluid-burial history in methane seep provinces. Results from our core analyses are integrated with observations made during the CAGE15-2 cruise in May 2015, when we deployed a towed vehicle equipped with camera, multicore and water sampling capabilities. The instrument design was based on the Woods Hole Oceanographic Institution (WHOI) MISO TowCam sled equipped with a deep-sea digital camera and CTD real-time system. Sediment sampling was visually-guided using this system. In one of the pockmarks along the Vestnesa Ridge where high

Recent advances in methane activation

Energy Technology Data Exchange (ETDEWEB)

Huuska, M; Kataja, K [VTT Chemical Technology, Espoo (Finland)

1997-12-31

Considerable work has been done in the research and development of methane conversion technologies. Although some promising conversion processes have been demonstrated, further advances in engineering and also in the chemistry are needed before these technologies become commercial. High-temperature processes, e.g. the oxidative coupling of methane, studied thoroughly during the last 15 years, suffer from severe theoretical yield limits and poor economics. In the long term, the most promising approaches seem to be the organometallic and, especially, the biomimetic activation of methane. (author) (22 refs.)

Recent advances in methane activation

Energy Technology Data Exchange (ETDEWEB)

Huuska, M.; Kataja, K. [VTT Chemical Technology, Espoo (Finland)

1996-12-31

Considerable work has been done in the research and development of methane conversion technologies. Although some promising conversion processes have been demonstrated, further advances in engineering and also in the chemistry are needed before these technologies become commercial. High-temperature processes, e.g. the oxidative coupling of methane, studied thoroughly during the last 15 years, suffer from severe theoretical yield limits and poor economics. In the long term, the most promising approaches seem to be the organometallic and, especially, the biomimetic activation of methane. (author) (22 refs.)

Methane hydroxylation: a biomimetic approach

International Nuclear Information System (INIS)

Shilov, Aleksandr E; Shteinman, Al'bert A

2012-01-01

The review addresses direct methane oxidation — an important fundamental problem, which has attracted much attention of researchers in recent years. Analysis of the available results on biomimetic and bio-inspired methane oxygenation has demonstrated that assimilating of the experience of Nature on oxidation of methane and other alkanes significantly enriches the arsenal of chemistry and can radically change the character of the entire chemical production, as well as enables the solution of many material, energetic and environmental problems. The bibliography includes 310 references.

Raman studies of methane-ethane hydrate metastability.

Science.gov (United States)

Ohno, Hiroshi; Strobel, Timothy A; Dec, Steven F; Sloan, E Dendy; Koh, Carolyn A

2009-03-05

The interconversion of methane-ethane hydrate from metastable to stable structures was studied using Raman spectroscopy. sI and sII hydrates were synthesized from methane-ethane gas mixtures of 65% or 93% methane in ethane and water, both with and without the kinetic hydrate inhibitor, poly(N-vinylcaprolactam). The observed faster structural conversion rate in the higher methane concentration atmosphere can be explained in terms of the differences in driving force (difference in chemical potential of water in sI and sII hydrates) and kinetics (mass transfer of gas and water rearrangement). The kinetic hydrate inhibitor increased the conversion rate at 65% methane in ethane (sI is thermodynamically stable) but retards the rate at 93% methane in ethane (sII is thermodynamically stable), implying there is a complex interaction between the polymer, water, and hydrate guests at crystal surfaces.

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.

Anthropogenic combustion iron as a complex climate forcer.

Science.gov (United States)

Matsui, Hitoshi; Mahowald, Natalie M; Moteki, Nobuhiro; Hamilton, Douglas S; Ohata, Sho; Yoshida, Atsushi; Koike, Makoto; Scanza, Rachel A; Flanner, Mark G

2018-04-23

Atmospheric iron affects the global carbon cycle by modulating ocean biogeochemistry through the deposition of soluble iron to the ocean. Iron emitted by anthropogenic (fossil fuel) combustion is a source of soluble iron that is currently considered less important than other soluble iron sources, such as mineral dust and biomass burning. Here we show that the atmospheric burden of anthropogenic combustion iron is 8 times greater than previous estimates by incorporating recent measurements of anthropogenic magnetite into a global aerosol model. This new estimation increases the total deposition flux of soluble iron to southern oceans (30-90 °S) by 52%, with a larger contribution of anthropogenic combustion iron than dust and biomass burning sources. The direct radiative forcing of anthropogenic magnetite is estimated to be 0.021 W m -2 globally and 0.22 W m -2 over East Asia. Our results demonstrate that anthropogenic combustion iron is a larger and more complex climate forcer than previously thought, and therefore plays a key role in the Earth system.

Methane production from cheese whey

Energy Technology Data Exchange (ETDEWEB)

Yan, J Q; Liao, P H; Lo, K V

1988-01-01

Cheese whey was treated in a 17.5-litre laboratory-scale up-flow anaerobic sludge blanket reactor operated over a range of hydraulic retention times and organic loading rates. The reactor performance was determined in terms of methane production, volatile fatty acids conversion and chemical oxygen demand (COD) reduction. At a constant influent strength, the methane production rate decreased with decreasing hydraulic retention time. At constant hydraulic retention time the methane production rate increased as the influent strength was increased up to a concentration of 28.8 g COD litre/sup -1/. The methane production rate was similar for two influent concentrations studied at hydraulic retention times longer than 10 days. The effect of short hydraulic retention times on methane production rate was more pronounced for the higher influent concentration than for the lower influent concentration. The highest methane production rate of 9.57 litres CH/sub 4/ litre/sup -1/ feed day/sup -1/ was obtained at a loading rate of 5.96 g/sup -1/ COD litre/sup -1/ and an influent concentration of 28.8 g COD litre/sup -1/. A high treatment efficiency in terms of chemical oxygen demand reduction was obtained. In general, over 98% removal of chemical oxygen demand was achieved. The results indicated that anaerobic digestion of cheese whey using an upflow sludge blanket reactor could reduce pollution strength and produce energy for a cheese plant.

The California Baseline Methane Survey

Science.gov (United States)

Duren, R. M.; Thorpe, A. K.; Hopkins, F. M.; Rafiq, T.; Bue, B. D.; Prasad, K.; Mccubbin, I.; Miller, C. E.

2017-12-01

The California Baseline Methane Survey is the first systematic, statewide assessment of methane point source emissions. The objectives are to reduce uncertainty in the state's methane budget and to identify emission mitigation priorities for state and local agencies, utilities and facility owners. The project combines remote sensing of large areas with airborne imaging spectroscopy and spatially resolved bottom-up data sets to detect, quantify and attribute emissions from diverse sectors including agriculture, waste management, oil and gas production and the natural gas supply chain. Phase 1 of the project surveyed nearly 180,000 individual facilities and infrastructure components across California in 2016 - achieving completeness rates ranging from 20% to 100% per emission sector at < 5 meters spatial resolution. Additionally, intensive studies of key areas and sectors were performed to assess source persistence and variability at times scales ranging from minutes to months. Phase 2 of the project continues with additional data collection in Spring and Fall 2017. We describe the survey design and measurement, modeling and analysis methods. We present initial findings regarding the spatial, temporal and sectoral distribution of methane point source emissions in California and their estimated contribution to the state's total methane budget. We provide case-studies and lessons learned about key sectors including examples where super-emitters were identified and mitigated. We summarize challenges and recommendations for future methane research, inventories and mitigation guidance within and beyond California.

Emerging role of wetland methane emissions in driving 21st century climate change.

Science.gov (United States)

Zhang, Zhen; Zimmermann, Niklaus E; Stenke, Andrea; Li, Xin; Hodson, Elke L; Zhu, Gaofeng; Huang, Chunlin; Poulter, Benjamin

2017-09-05

Wetland methane (CH 4 ) emissions are the largest natural source in the global CH 4 budget, contributing to roughly one third of total natural and anthropogenic emissions. As the second most important anthropogenic greenhouse gas in the atmosphere after CO 2 , CH 4 is strongly associated with climate feedbacks. However, due to the paucity of data, wetland CH 4 feedbacks were not fully assessed in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The degree to which future expansion of wetlands and CH 4 emissions will evolve and consequently drive climate feedbacks is thus a question of major concern. Here we present an ensemble estimate of wetland CH 4 emissions driven by 38 general circulation models for the 21st century. We find that climate change-induced increases in boreal wetland extent and temperature-driven increases in tropical CH 4 emissions will dominate anthropogenic CH 4 emissions by 38 to 56% toward the end of the 21st century under the Representative Concentration Pathway (RCP2.6). Depending on scenarios, wetland CH 4 feedbacks translate to an increase in additional global mean radiative forcing of 0.04 W·m -2 to 0.19 W·m -2 by the end of the 21st century. Under the "worst-case" RCP8.5 scenario, with no climate mitigation, boreal CH 4 emissions are enhanced by 18.05 Tg to 41.69 Tg, due to thawing of inundated areas during the cold season (December to May) and rising temperature, while tropical CH 4 emissions accelerate with a total increment of 48.36 Tg to 87.37 Tg by 2099. Our results suggest that climate mitigation policies must consider mitigation of wetland CH 4 feedbacks to maintain average global warming below 2 °C.

Crenothrix are major methane consumers in stratified lakes.

Science.gov (United States)

Oswald, Kirsten; Graf, Jon S; Littmann, Sten; Tienken, Daniela; Brand, Andreas; Wehrli, Bernhard; Albertsen, Mads; Daims, Holger; Wagner, Michael; Kuypers, Marcel Mm; Schubert, Carsten J; Milucka, Jana

2017-09-01

Methane-oxidizing bacteria represent a major biological sink for methane and are thus Earth's natural protection against this potent greenhouse gas. Here we show that in two stratified freshwater lakes a substantial part of upward-diffusing methane was oxidized by filamentous gamma-proteobacteria related to Crenothrix polyspora. These filamentous bacteria have been known as contaminants of drinking water supplies since 1870, but their role in the environmental methane removal has remained unclear. While oxidizing methane, these organisms were assigned an 'unusual' methane monooxygenase (MMO), which was only distantly related to 'classical' MMO of gamma-proteobacterial methanotrophs. We now correct this assignment and show that Crenothrix encode a typical gamma-proteobacterial PmoA. Stable isotope labeling in combination swith single-cell imaging mass spectrometry revealed methane-dependent growth of the lacustrine Crenothrix with oxygen as well as under oxygen-deficient conditions. Crenothrix genomes encoded pathways for the respiration of oxygen as well as for the reduction of nitrate to N 2 O. The observed abundance and planktonic growth of Crenothrix suggest that these methanotrophs can act as a relevant biological sink for methane in stratified lakes and should be considered in the context of environmental removal of methane.

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog.

Science.gov (United States)

Reumer, Max; Harnisz, Monika; Lee, Hyo Jung; Reim, Andreas; Grunert, Oliver; Putkinen, Anuliina; Fritze, Hannu; Bodelier, Paul L E; Ho, Adrian

2018-02-01

Ombrotrophic peatlands are a recognized global carbon reservoir. Without restoration and peat regrowth, harvested peatlands are dramatically altered, impairing their carbon sink function, with consequences for methane turnover. Previous studies determined the impact of commercial mining on the physicochemical properties of peat and the effects on methane turnover. However, the response of the underlying microbial communities catalyzing methane production and oxidation have so far received little attention. We hypothesize that with the return of Sphagnum spp. postharvest, methane turnover potential and the corresponding microbial communities will converge in a natural and restored peatland. To address our hypothesis, we determined the potential methane production and oxidation rates in natural (as a reference), actively mined, abandoned, and restored peatlands over two consecutive years. In all sites, the methanogenic and methanotrophic population sizes were enumerated using quantitative PCR (qPCR) assays targeting the mcrA and pmoA genes, respectively. Shifts in the community composition were determined using Illumina MiSeq sequencing of the mcrA gene and a pmoA -based terminal restriction fragment length polymorphism (t-RFLP) analysis, complemented by cloning and sequence analysis of the mmoX gene. Peat mining adversely affected methane turnover potential, but the rates recovered in the restored site. The recovery in potential activity was reflected in the methanogenic and methanotrophic abundances. However, the microbial community composition was altered, being more pronounced for the methanotrophs. Overall, we observed a lag between the recovery of the methanogenic/methanotrophic activity and the return of the corresponding microbial communities, suggesting that a longer duration (>15 years) is needed to reverse mining-induced effects on the methane-cycling microbial communities. IMPORTANCE Ombrotrophic peatlands are a crucial carbon sink, but this environment

Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers

International Nuclear Information System (INIS)

Albanna, Muna; Warith, Mostafa; Fernandes, Leta

2010-01-01

In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH 4 ) oxidation process were examined. The investigation was performed on compost experiments incubated with CH 4 and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH 4 oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 deg. C without any NMOCs the V max value was 35.0 μg CH 4 h -1 g wetwt -1 . This value was reduced to 19.1 μg CH 4 h -1 g wetwt -1 when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH 4 in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.

Methane emissions from a Californian landfill, determined from airborne remote sensing and in situ measurements

Science.gov (United States)

Krautwurst, Sven; Gerilowski, Konstantin; Jonsson, Haflidi H.; Thompson, David R.; Kolyer, Richard W.; Iraci, Laura T.; Thorpe, Andrew K.; Horstjann, Markus; Eastwood, Michael; Leifer, Ira; Vigil, Samuel A.; Krings, Thomas; Borchardt, Jakob; Buchwitz, Michael; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

2017-09-01

Fugitive emissions from waste disposal sites are important anthropogenic sources of the greenhouse gas methane (CH4). As a result of the growing world population and the recognition of the need to control greenhouse gas emissions, this anthropogenic source of CH4 has received much recent attention. However, the accurate assessment of the CH4 emissions from landfills by modeling and existing measurement techniques is challenging. This is because of inaccurate knowledge of the model parameters and the extent of and limited accessibility to landfill sites. This results in a large uncertainty in our knowledge of the emissions of CH4 from landfills and waste management. In this study, we present results derived from data collected during the research campaign COMEX (CO2 and MEthane eXperiment) in late summer 2014 in the Los Angeles (LA) Basin. One objective of COMEX, which comprised aircraft observations of methane by the remote sensing Methane Airborne MAPper (MAMAP) instrument and a Picarro greenhouse gas in situ analyzer, was the quantitative investigation of CH4 emissions. Enhanced CH4 concentrations or CH4 plumes were detected downwind of landfills by remote sensing aircraft surveys. Subsequent to each remote sensing survey, the detected plume was sampled within the atmospheric boundary layer by in situ measurements of atmospheric parameters such as wind information and dry gas mixing ratios of CH4 and carbon dioxide (CO2) from the same aircraft. This was undertaken to facilitate the independent estimation of the surface fluxes for the validation of the remote sensing estimates. During the COMEX campaign, four landfills in the LA Basin were surveyed. One landfill repeatedly showed a clear emission plume. This landfill, the Olinda Alpha Landfill, was investigated on 4 days during the last week of August and first days of September 2014. Emissions were estimated for all days using a mass balance approach. The derived emissions vary between 11.6 and 17.8 kt CH4 yr-1

Differentiation of pre-existing trapped methane from thermogenic methane in an igneous-intruded coal by hydrous pyrolysis

Science.gov (United States)

Dias, Robert F.; Lewan, Michael D.; Birdwell, Justin E.; Kotarba, Maciej J.

2014-01-01

So as to better understand how the gas generation potential of coal changes with increasing rank, same-seam samples of bituminous coal from the Illinois Basin that were naturally matured to varying degrees by the intrusion of an igneous dike were subjected to hydrous pyrolysis (HP) conditions of 360 °C for 72 h. The accumulated methane in the reactor headspace was analyzed for δ13C and δ2H, and mol percent composition. Maximum methane production (9.7 mg/g TOC) occurred in the most immature samples (0.5 %Ro), waning to minimal methane values at 2.44 %Ro (0.67 mg/g TOC), and rebounding to 3.6 mg/g TOC methane in the most mature sample (6.76 %Ro). Methane from coal with the highest initial thermal maturity (6.76 %Ro) shows no isotopic dependence on the reactor water and has a microbial δ13C value of −61‰. However, methane from coal of minimal initial thermal maturity (0.5 %Ro) shows hydrogen isotopic dependence on the reaction water and has a δ13C value of −37‰. The gas released from coals under hydrous pyrolysis conditions represents a quantifiable mixture of ancient (270 Ma) methane (likely microbial) that was generated in situ and trapped within the rock during the rapid heating by the dike, and modern (laboratory) thermogenic methane that was generated from the indigenous organic matter due to thermal maturation induced by hydrous pyrolysis conditions. These findings provide an analytical framework for better assessment of natural gas sources and for differentiating generated gas from pre-existing trapped gas in coals of various ranks.

Status and potential of bio-methane fuel

International Nuclear Information System (INIS)

2008-01-01

This document first indicates and describes the various bio-methane production processes which can be implemented on a short term (use of organic wastes or effluents), on a medium term (from energetic crops) and on a longer term (gasification). It discusses and assesses the potential production of bio-methane fuel from different sources and processes. It describes the steps of the production of bio-methane fuel from biogas, with notably biogas refinement to produce bio-methane through three processes (de-carbonation, desulfurization, dehydration). Cost productions are assessed. Expected technology advances are evoked. Finally, the authors outline the contribution of bio-methane in the limitation of greenhouse gas emissions in the transport sector

SAES St 909 pilot scale methane cracking tests

International Nuclear Information System (INIS)

Klein, J. E.; Sessions, H. T.

2008-01-01

Pilot scale (0.5 kg) SAES St 909 methane cracking tests were conducted for potential tritium process applications. Up to 1400 hours tests were done at 700 deg.C, 202.7 kPa (1520 torr) with a 0.03 sLPM feed of methane plus impurities, in a 20 vol% hydrogen, balance helium, stream. Carbon dioxide gettered by St 909 can be equated to an equivalent amount of methane gettered, but equating nitrogen to an equivalent amount of methane was nitrogen feed composition dependent. A decreased hydrogen feed increased methane getter rates while a 30 deg.C drop in one furnace zone increased methane emissions by over a factor of 30. The impact of gettered nitrogen can be somewhat minimized if nitrogen feed to the bed has been stopped and sufficient time given to recover the methane cracking rate. (authors)

75 FR 9886 - Methane Hydrate Advisory Committee

Science.gov (United States)

2010-03-04

... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Department of Energy, Office of Fossil Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Methane... the Committee: The purpose of the Methane Hydrate Advisory Committee is to provide advice on potential...

Bio-methane via fast pyrolysis of biomass

International Nuclear Information System (INIS)

Görling, Martin; Larsson, Mårten; Alvfors, Per

2013-01-01

Highlights: ► Pyrolysis gases can efficiently be upgraded to bio-methane. ► The integration can increase energy efficiency and provide a renewable vehicle fuel. ► The biomass to bio-methane conversion efficiency is 83% (HHV). ► The efficiency is higher compared to bio-methane produced via gasification. ► Competitive alternative to other alternatives of bio-oil upgrading. - Abstract: Bio-methane, a renewable vehicle fuel, is today produced by anaerobic digestion and a 2nd generation production route via gasification is under development. This paper proposes a poly-generation plant that produces bio-methane, bio-char and heat via fast pyrolysis of biomass. The energy and material flows for the fuel synthesis are calculated by process simulation in Aspen Plus®. The production of bio-methane and bio-char amounts to 15.5 MW and 3.7 MW, when the total inputs are 23 MW raw biomass and 1.39 MW electricity respectively (HHV basis). The results indicate an overall efficiency of 84% including high-temperature heat and the biomass to bio-methane yield amounts to 83% after allocation of the biomass input to the final products (HHV basis). The overall energy efficiency is higher for the suggested plant than for the gasification production route and is therefore a competitive route for bio-methane production

Paradox reconsidered: Methane oversaturation in well-oxygenated lake waters

DEFF Research Database (Denmark)

Tang, Kam W.; McGinnis, Daniel F.; Frindte, Katharina

2014-01-01

The widely reported paradox of methane oversaturation in oxygenated water challenges the prevailing paradigm that microbial methanogenesis only occurs under anoxic conditions. Using a combination of field sampling, incubation experiments, and modeling, we show that the recurring mid-water methane...... peak in Lake Stechlin, northeast Germany, was not dependent on methane input from the littoral zone or bottom sediment or on the presence of known micro-anoxic zones. The methane peak repeatedly overlapped with oxygen oversaturation in the seasonal thermocline. Incubation experiments and isotope...... analysis indicated active methane production, which was likely linked to photosynthesis and/or nitrogen fixation within the oxygenated water, whereas lessening of methane oxidation by light allowed accumulation of methane in the oxygen-rich upper layer. Estimated methane efflux from the surface water...

The determination of methane resources from liquidated coal mines

Science.gov (United States)

Trenczek, Stanisław

2017-11-01

The article refers to methane presented in hard coal seams, which may pose a serious risk to workers, as evidenced by examples of incidents, and may also be a high energy source. That second issue concerns the possibility of obtaining methane from liquidated coal mines. There is discussed the current methodology for determination of methane resources from hard coal deposits. Methods of assessing methane emissions from hard coal deposits are given, including the degree of rock mass fracture, which is affected and not affected by mining. Additional criteria for methane recovery from the methane deposit are discussed by one example (of many types) of methane power generation equipment in the context of the estimation of potential viable resources. Finally, the concept of “methane resource exploitation from coal mine” refers to the potential for exploitation of the resource and the acquisition of methane for business purposes.

30 CFR 75.323 - Actions for excessive methane.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Actions for excessive methane. 75.323 Section... excessive methane. (a) Location of tests. Tests for methane concentrations under this section shall be made.... (1) When 1.0 percent or more methane is present in a working place or an intake air course, including...

methanization of organic matters. Guide for project developers

International Nuclear Information System (INIS)

2015-02-01

This document aims at informing potential project developers (farmers, local communities, industrials) all along the creation of a methanization unit. It precisely indicates administrative procedures required to complete a project. It first presents some generalities about methanization (matters and their performance, methanization cycle, biogas), describes methanization processes (dry and humid), and valorisation processes (co-generation, hot water production, gas injection into the public network), presents digestate characteristics, and discusses benefits and drawbacks of methanization. The different steps of a project management are then analysed. Additional procedures are indicated, and risks and traps of methanization projects are highlighted. The document comes along with a large number of appendices which can be documents released by professional or public bodies

METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 13: CHEMICAL INJECTION PUMPS

Science.gov (United States)

The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

International Methane Partnership Fighting Climate Change

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

Due to the growth of international attention on the problem of climate change combined with the attractiveness of methane mitigation technologies, the capture and use of methane in agriculture, coal mines, landfills, and the oil and gas sector has increasingly become popular over the past few years. Highlighting this, several countries hosted the international 'Methane to Market' Partnership Conference and Exposition in October 2007 in Beijing, China.

Methane production from acid hydrolysates of Agave tequilana bagasse: evaluation of hydrolysis conditions and methane yield.

Science.gov (United States)

Arreola-Vargas, Jorge; Ojeda-Castillo, Valeria; Snell-Castro, Raúl; Corona-González, Rosa Isela; Alatriste-Mondragón, Felipe; Méndez-Acosta, Hugo O

2015-04-01

Evaluation of diluted acid hydrolysis for sugar extraction from cooked and uncooked Agave tequilana bagasse and feasibility of using the hydrolysates as substrate for methane production, with and without nutrient addition, in anaerobic sequencing batch reactors (AnSBR) were studied. Results showed that the hydrolysis over the cooked bagasse was more effective for sugar extraction at the studied conditions. Total sugars concentration in the cooked and uncooked bagasse hydrolysates were 27.9 g/L and 18.7 g/L, respectively. However, 5-hydroxymethylfurfural was detected in the cooked bagasse hydrolysate, and therefore, the uncooked bagasse hydrolysate was selected as substrate for methane production. Interestingly, results showed that the AnSBR operated without nutrient addition obtained a constant methane production (0.26 L CH4/g COD), whereas the AnSBR operated with nutrient addition presented a gradual methane suppression. Molecular analyses suggested that methane suppression in the experiment with nutrient addition was due to a negative effect over the archaeal/bacterial ratio. Copyright © 2015. Published by Elsevier Ltd.

Variability and quasi-decadal changes in the methane budget over the period 2000–2012

Directory of Open Access Journals (Sweden)

M. Saunois

2017-09-01

Full Text Available Following the recent Global Carbon Project (GCP synthesis of the decadal methane (CH4 budget over 2000–2012 (Saunois et al., 2016, we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000–2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000–2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008–2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16–32] Tg CH4 yr−1 higher methane emissions over the period 2008–2012 compared to 2002–2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002–2006 and 2008–2012 differs from one atmospheric inversion study to

Methane yield enhancement via electroporation of organic waste.

Science.gov (United States)

Safavi, Seyedeh Masoumeh; Unnthorsson, Runar

2017-08-01

An experimental study with pulsed electric field (PEF) pre-treatment was conducted to investigate its effect on methane production. PEF pre-treatment converts organic solids into soluble and colloidal forms, increasing bioavailability for anaerobic microorganisms participating in methane generation process. The substrates tested were landfill leachate and fruit/vegetable. Three treatment intensities of 15, 30, and 50kWh/m 3 were applied to investigate the influence of pre-treatment on methane production via biochemical methane potential test. Threshold treatment intensity was found to be around 30kWh/m 3 for landfill leachate beyond which the methane production enhanced linearly with increase in intensity. Methane production of the landfill leachate significantly increased up to 44% with the highest intensity. The result of pulsed electric field pre-treatment on fruit/vegetable showed that 15kWh/m 3 was the intensity by which the highest amount of methane (up to 7%) was achieved. Beyond this intensity, the methane production decreased. Chemical oxygen demand removals were increased up to 100% for landfill leachate and 17% for fruit/vegetable, compared to the untreated slurries. Results indicate that the treatment intensity has a significant effect on the methane production and biosolid removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigations of Methane Production in Hypersaline Environments

Science.gov (United States)

Bebout, Brad M.

2015-01-01

The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleo-environments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption. Methane in the atmosphere of Mars may be an indication of life but might also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. Hypersaline environments have now been reported to be extremely likely in several locations in our solar system, including: Mars, Europa, and Enceladus. Modern hypersaline microbial mat communities, (thought to be analogous to those present on the early Earth at a period of time when Mars was experiencing very similar environmental conditions), have been shown to produce methane. However, very little is known about the physical and/or biological controls imposed upon the rates at which methane, and other important trace gases, are produced and consumed in these environments. We describe here the results of our investigations of methane production in hypersaline environments, including field sites in Chile, Baja California Mexico, California, USA and the United Arab Emirates. We have measured high concentrations of methane in bubbles of gas produced both in the sediments underlying microbial mats, as well as in areas not colonized by microbial mats in the Guerrero Negro hypersaline ecosystem, Baja California Mexico, in Chile, and in salt ponds on the San Francisco Bay. The carbon isotopic (d13C) composition of the methane in the bubbles exhibited an extremely wide range of values, (ca. -75 per mille ca. -25 per mille). The hydrogen isotopic composition of the methane (d2H) ranged from -60 to -30per mille and -450 to -350per mille. These isotopic values are outside of the range of values normally considered to be biogenic, however incubations of the sediments in contact with these gas bubbles reveals that the methane is indeed being

Methanation of hydrogen and carbon dioxide

International Nuclear Information System (INIS)

Burkhardt, Marko; Busch, Günter

2013-01-01

Highlights: • The biologic methanation of exclusively gases like hydrogen and carbon dioxide is feasible. • Electrical energy can be stored in the established gas grid by conversion to methane. • The quality of produced biogas is very high (c CH4 = 98 vol%). • The conversion rate is depending on H 2 -flow rate. - Abstract: A new method for the methanation of hydrogen and carbon dioxide is presented. In a novel anaerobic trickle-bed reactor, biochemical catalyzed methanation at mesophilic temperatures and ambient pressure can be realized. The conversion of gaseous substrates by immobilized hydrogenotrophic methanogens is a unique feature of this reactor type. The already patented reactor produces biogas which has a very high quality (c CH4 = 97.9 vol%). Therefore, the storage of biogas in the existing natural gas grid is possible without extensive purification. The specific methane production was measured with P = 1.17 Nm CH4 3 /(m R 3 d). It is conceivable to realize the process at sites that generate solar or wind energy and sites subject to the conditions for hydrogen electrolysis (or other methods of hydrogen production). The combination with conventional biogas plants under hydrogen addition to methane enrichment is possible as well. The process enables the coupling of various renewable energy sources

Methane emissions from different coastal wetlands in New England, US

Science.gov (United States)

Wang, F.; Tang, J.; Kroeger, K. D.; Gonneea, M. E.

2017-12-01

According to the IPCC, methane have 25 times warming effect than CO2, and natural wetlands contribute 20-39 % to the global emission of methane. Although most of these methane was from inland wetlands, there was still large uncertain in the methane emissions in coastal wetlands. In the past three years, we have investigated methane emissions in coastal wetlands in MA, USA. Contrary to previous assumptions, we have observed relative larger methane flux in some salt marshes than freshwater wetlands. We further detect the methane source, and found that plant activities played an important role in methane flux, for example, the growth of S. aterniflora, the dominate plants in salt marsh, could enhance methane emission, while in an fresh water wetland that was dominated by cattail, plant activity oxided methane and reduced total flux. Phragmite, an invasive plant at brackish marsh, have the highest methane flux among all coastal wetland investigated. This study indicated that coastal wetland could still emit relatively high amount of methane even under high water salinity condiations, and plant activity played an important role in methane flux, and this role was highly species-specific.

Australian methane fluxes

International Nuclear Information System (INIS)

Williams, D.J.

1990-01-01

Estimates are provided for the amount of methane emitted annually into the atmosphere in Australia for a variety of sources. The sources considered are coal mining, landfill, motor vehicles, natural gas suply system, rice paddies, bushfires, termites, wetland and animals. This assessment indicates that the major sources of methane are natural or agricultural in nature and therefore offer little scope for reduction. Nevertheless the remainder are not trival and reduction of these fluxes could play a significant part in any Australian action on the greenhouse problem. 19 refs., 7 tabs., 1 fig

Abiotic production of methane in terrestrial planets.

Science.gov (United States)

Guzmán-Marmolejo, Andrés; Segura, Antígona; Escobar-Briones, Elva

2013-06-01

On Earth, methane is produced mainly by life, and it has been proposed that, under certain conditions, methane detected in an exoplanetary spectrum may be considered a biosignature. Here, we estimate how much methane may be produced in hydrothermal vent systems by serpentinization, its main geological source, using the kinetic properties of the main reactions involved in methane production by serpentinization. Hydrogen production by serpentinization was calculated as a function of the available FeO in the crust, given the current spreading rates. Carbon dioxide is the limiting reactant for methane formation because it is highly depleted in aqueous form in hydrothermal vent systems. We estimated maximum CH4 surface fluxes of 6.8×10(8) and 1.3×10(9) molecules cm(-2) s(-1) for rocky planets with 1 and 5 M⊕, respectively. Using a 1-D photochemical model, we simulated atmospheres with volume mixing ratios of 0.03 and 0.1 CO2 to calculate atmospheric methane concentrations for the maximum production of this compound by serpentinization. The resulting abundances were 2.5 and 2.1 ppmv for 1 M⊕ planets and 4.1 and 3.7 ppmv for 5 M⊕ planets. Therefore, low atmospheric concentrations of methane may be produced by serpentinization. For habitable planets around Sun-like stars with N2-CO2 atmospheres, methane concentrations larger than 10 ppmv may indicate the presence of life.

Methane of the coal

International Nuclear Information System (INIS)

Vasquez, H.

1997-01-01

In the transformation process of the vegetable material to the coal (Carbonization), the products that are generated include CH 4, CO2, N2 and H2. The methane is generated by two mechanisms: below 50 centigrade degree, as product of microbial decomposition, the methanogenic is generated; and above 50 centigrade degree, due to the effects of the buried and increase of the range of the coal, the thermogenic methane is detachment, as a result of the catagenic. The generated methane is stored in the internal surfaces of the coal, macro and micro pores and in the natural fractures. The presence of accumulations of gas of the coal has been known in the entire world by many years, but only as something undesirable for its danger in the mining exploitation of the coal

Demonstration of an ethane spectrometer for methane source identification.

Science.gov (United States)

Yacovitch, Tara I; Herndon, Scott C; Roscioli, Joseph R; Floerchinger, Cody; McGovern, Ryan M; Agnese, Michael; Pétron, Gabrielle; Kofler, Jonathan; Sweeney, Colm; Karion, Anna; Conley, Stephen A; Kort, Eric A; Nähle, Lars; Fischer, Marc; Hildebrandt, Lars; Koeth, Johannes; McManus, J Barry; Nelson, David D; Zahniser, Mark S; Kolb, Charles E

2014-07-15

Methane is an important greenhouse gas and tropospheric ozone precursor. Simultaneous observation of ethane with methane can help identify specific methane source types. Aerodyne Ethane-Mini spectrometers, employing recently available mid-infrared distributed feedback tunable diode lasers (DFB-TDL), provide 1 s ethane measurements with sub-ppb precision. In this work, an Ethane-Mini spectrometer has been integrated into two mobile sampling platforms, a ground vehicle and a small airplane, and used to measure ethane/methane enhancement ratios downwind of methane sources. Methane emissions with precisely known sources are shown to have ethane/methane enhancement ratios that differ greatly depending on the source type. Large differences between biogenic and thermogenic sources are observed. Variation within thermogenic sources are detected and tabulated. Methane emitters are classified by their expected ethane content. Categories include the following: biogenic (6%), pipeline grade natural gas (30%). Regional scale observations in the Dallas/Fort Worth area of Texas show two distinct ethane/methane enhancement ratios bridged by a transitional region. These results demonstrate the usefulness of continuous and fast ethane measurements in experimental studies of methane emissions, particularly in the oil and natural gas sector.

Methane emission by bubbling from Gatun Lake, Panama

Science.gov (United States)

Keller, Michael; Stallard, Robert F.

1994-01-01

We studied methane emission by bubbling from Gatun Lake, Panama, at water depths of less than 1 m to about 10 m. Gas bubbles were collected in floating traps deployed during 12- to 60-hour observation periods. Comparison of floating traps and floating chambers showed that about 98% of methane emission occurred by bubbling and only 2% occurred by diffusion. Average methane concentration of bubbles at our sites varied from 67% to 77%. Methane emission by bubbling occurred episodically, with greatest rates primarily between the hours of 0800 and 1400 LT. Events appear to be triggered by wind. The flux of methane associated with bubbling was strongly anticorrelated with water depth. Seasonal changes in water depth caused seasonal variation of methane emission. Bubble methane fluxes through the lake surface into the atmosphere measured during 24-hour intervals were least (10-200 mg/m2/d) at deeper sites (greater than 7 m) and greatest (300-2000 mg/m2/d) at shallow sites (less than 2 m).

Composite hydrogen-solid methane moderators

International Nuclear Information System (INIS)

Picton, D.; Bennington, S.; Ansell, S.; Fernandez-Garcia, J.; Broome, T.

2004-01-01

This paper describes the results of Monte-Carlo calculations for a coupled moderator on a low-power pulsed neutron spallation source and is part of the design study for a second target station for the ISIS spallation source. Various options were compared including hydrogen, solid methane, grooving the solid methane and compound moderators made of hydrogen in front of solid methane. To maximise the neutron current at low energies two strategies appear to emerge from the calculations. For instruments that view a large area of moderator surface a layer of hydrogen in front of a thin solid-methane moderator is optimum, giving a gain of about a factor 10 relative to the current liquid hydrogen moderator on the existing ISIS tantalum target. For instruments that only view a restricted area higher flux, corresponding to a gain of 13.5, can be achieved with the use of a single groove or re-entrant hole in the moderator. (orig.)

Coprecipitated nickel-alumina methanation catalysts

International Nuclear Information System (INIS)

Kruissink, E.C.

1981-01-01

In the last few years there has been a renewed interest in the methanation reaction CO+3H 2 =CH 4 +H 2 O. The investigations described in this thesis were performed in relation to the application of this reaction, within the framework of the so-called 'NFE' project, also called 'ADAM' and 'EVA' project. This project, which has been under investigation in West Germany for some years, aims at the investigation of the feasibility of transporting heat from a nuclear high temperature reactor by means of a chemical cycle. A promising possibility to realize such a cycle exists in applying the combination of the endothermic steam reforming of methane and the exothermic methanation reaction. This thesis describes the investigations into a certain type of methanation catalyst, viz. a coprecipitated nickel-alumina catalyst, with the aim to give more insight into the interrelationship between the preparation conditions on the one hand and catalyst properties such as activity and stability on the other hand. (Auth.)

Ductile flow of methane hydrate

Science.gov (United States)

Durham, W.B.; Stern, L.A.; Kirby, S.H.

2003-01-01

Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

Methane distribution and methane oxidation in the water column of the Elbe estuary, Germany

Czech Academy of Sciences Publication Activity Database

Matoušů, Anna; Osudar, R.; Šimek, Karel; Bussmann, I.

2017-01-01

Roč. 79, č. 3 (2017), s. 443-458 ISSN 1015-1621 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : estuary * methane * methane budget * ethane oxidation * River Elbe Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 2.821, year: 2016

Termites facilitate methane oxidation and shape the methanotrophic community

NARCIS (Netherlands)

Ho, A.; Erens, H.; Mujinya, B.B.; Boeckx, P.; Baert, G.; Schneider, B.; Frenzel, P.; Boon, N.; Van Ranst, E.

2013-01-01

Termite-derived methane contributes 3-4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of methane produced can be consumed by methanotrophs that inhabit the mound material. Yet, methanotroph

The direct aromatization of methane

Energy Technology Data Exchange (ETDEWEB)

Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

1995-12-31

The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

Bio-methane. Challenges and technical solutions

International Nuclear Information System (INIS)

Blaisonneau, Laurent; Carlu, Elieta; Feuillette, Vincent

2012-06-01

Among the new energy sectors in development, biogas has many benefits: several valorization possibilities (bio-methane, electricity and heat), continuous production, easy storage. In Europe, and particularly in France, the bio-methane market will be in the next years a driver for the improvement of the economic, environmental and social performance of the actors of the value chain of biogas. ENEA releases a report on the current state of the bio-methane market in Europe. This publication mainly describes: An outlook of the market evolution and the corresponding stakes for the actors of this sector, the technical and economic characteristics, maturity level and specificities of each biogas upgrading process, An analysis of the French regulatory framework for bio-methane injection into the grid

Exploiting coalbed methane and protecting the global environment

Energy Technology Data Exchange (ETDEWEB)

Yuheng, Gao

1996-12-31

The global climate change caused by greenhouse gases (GHGs) emission has received wide attention from all countries in the world. Global environmental protection as a common problem has confronted the human being. As a main component of coalbed methane, methane is an important factor influencing the production safety of coal mine and threatens the lives of miners. The recent research on environment science shows that methane is a very harmful GHG. Although methane gas has very little proportion in the GHGs emission and its stayed period is also very short, it has very obvious impact on the climate change. From the estimation, methane emission in the coal-mining process is only 10% of the total emission from human`s activities. As a clean energy, Methane has mature recovery technique before, during and after the process of mining. Thus, coalbed methane is the sole GHG generated in the human`s activities and being possible to be reclaimed and utilized. Compared with the global greenhouse effect of other GHGs emission abatement, coalbed methane emission abatement can be done in very low cost with many other benefits: (1) to protect global environment; (2) to improve obviously the safety of coal mine; and (3) to obtain a new kind of clean energy. Coal is the main energy in China, and coalbed contains very rich methane. According to the exploration result in recent years, about 30000{approximately}35000 billion m{sup 2} methane is contained in the coalbed below 2000 m in depth. China has formed a good development base in the field of reclamation and utilization of coalbed methane. The author hopes that wider international technical exchange and cooperation in the field will be carried out.

Terrestrial plant methane production

DEFF Research Database (Denmark)

Mikkelsen, Teis Nørgaard; Bruhn, Dan; Møller, Ian M.

We evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants. We conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH4 production, i.e. cutting injuries, increasing temperature...... the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

Methane adsorption on activated carbon

NARCIS (Netherlands)

Perl, Andras; Koopman, Folkert; Jansen, Peter; de Rooij, Marietta; van Gemert, Wim

2014-01-01

Methane storage in adsorbed form is a promising way to effectively and safely store fuel for vehicular transportation or for any other potential application. In a solid adsorbent, nanometer wide pores can trap methane by van der Waals forces as high density fluid at low pressure and room

Exhaled methane concentration profiles during exercise on an ergometer

Science.gov (United States)

Szabó, A; Ruzsanyi, V; Unterkofler, K; Mohácsi, Á; Tuboly, E; Boros, M; Szabó, G; Hinterhuber, H; Amann, A

2016-01-01

Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilationperfusion ratio and are in line with the Farhi equation. PMID:25749807

Methane: a new stake for negotiations on climate?

International Nuclear Information System (INIS)

2008-01-01

After having outlined that the issue of methane emissions could be, after the reduction of emissions from deforestation and degradation and the reduction of greenhouse gas emissions, an additional matter of discussion for the struggle against climate change, this article comments some data concerning methane emissions in six African countries. Generally, the main source of methane is agriculture (often more than 90 per cent) except in Gambia where wastes represent 77.8 per cent of methane emissions. This high level of methane emissions by agriculture could be a problem for these countries, whereas perspectives of waste valuation already exist

Atmospheric Ozone and Methane in a Changing Climate

Directory of Open Access Journals (Sweden)

Ivar S. A. Isaksen

2014-07-01

Full Text Available Ozone and methane are chemically active climate-forcing agents affected by climate–chemistry interactions in the atmosphere. Key chemical reactions and processes affecting ozone and methane are presented. It is shown that climate-chemistry interactions have a significant impact on the two compounds. Ozone, which is a secondary compound in the atmosphere, produced and broken down mainly in the troposphere and stratosphre through chemical reactions involving atomic oxygen (O, NOx compounds (NO, NO2, CO, hydrogen radicals (OH, HO2, volatile organic compounds (VOC and chlorine (Cl, ClO and bromine (Br, BrO. Ozone is broken down through changes in the atmospheric distribution of the afore mentioned compounds. Methane is a primary compound emitted from different sources (wetlands, rice production, livestock, mining, oil and gas production and landfills.Methane is broken down by the hydroxyl radical (OH. OH is significantly affected by methane emissions, defined by the feedback factor, currently estimated to be in the range 1.3 to 1.5, and increasing with increasing methane emission. Ozone and methane changes are affected by NOx emissions. While ozone in general increase with increases in NOx emission, methane is reduced, due to increases in OH. Several processes where current and future changes have implications for climate-chemistry interactions are identified. It is also shown that climatic changes through dynamic processes could have significant impact on the atmospheric chemical distribution of ozone and methane, as we can see through the impact of Quasi Biennial Oscillation (QBO. Modeling studies indicate that increases in ozone could be more pronounced toward the end of this century. Thawing permafrost could lead to important positive feedbacks in the climate system. Large amounts of organic material are stored in the upper layers of the permafrost in the yedoma deposits in Siberia, where 2 to 5% of the deposits could be organic material

Martian Methane From a Cometary Source: A Hypothesis

Science.gov (United States)

Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.;

Methane to bioproducts: the future of the bioeconomy?

Science.gov (United States)

Pieja, Allison J; Morse, Molly C; Cal, Andrew J

2017-12-01

Methanotrophs have been studied since the 1970s, but interest has increased tremendously in recent years due to their potential to transform methane into valuable bioproducts. The vast quantity of available methane and the low price of methane as natural gas have helped to spur this interest. The most well-studied, biologically-derived products from methane include methanol, polyhydroxyalkanoates, and single cell protein. However, many other high-interest chemicals such as biofuels or high-value products such as ectoine could be made industrially relevant through metabolic engineering. Although challenges must be overcome to achieve commercialization of biologically manufactured methane-to-products, taking a holistic view of the production process or radically re-imagining pathways could lead to a future bioeconomy with methane as the primary feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Aerial ``Sniffer Dog'' for Methane

Science.gov (United States)

Nathan, Brian; Schaefer, Dave; Zondlo, Mark; Khan, Amir; Lary, David

2012-10-01

The Earth's surface and its atmosphere maintain a ``Radiation Balance.'' Any factor which influences this balance is labeled as a mechanism of ``Radiative Forcing'' (RF). Greenhouse Gas (GHG) concentrations are among the most important forcing mechanisms. Methane, the second-most-abundant noncondensing greenhouse gas, is over 25 times more effective per molecule at radiating heat than the most abundant, Carbon Dioxide. Methane is also the principal component of Natural Gas, and gas leaks can cause explosions. Additionally, massive quantities of methane reside (in the form of natural gas) in underground shale basins. Recent technological advancements--specifically the combination of horizontal drilling and hydraulic fracturing--have allowed drillers access to portions of these ``plays'' which were previously unreachable, leading to an exponential growth in the shale gas industry. Presently, very little is known about the amount of methane which escapes into the global atmosphere from the extraction process. By using remote-controlled robotic helicopters equipped with specially developed trace gas laser sensors, we can get a 3-D profile of where and how methane is being released into the global atmosphere.

What drove the methane cycle in the past - evidence from carbon isotopic data of methane enclosed in polar ice cores

OpenAIRE

Möller, Lars

2013-01-01

During the last glacial cycle, greenhouse gas concentrations fluctuated on decadal and longer timescales. Concentrations of methane, as measured in polar ice cores, show a close connection with Northern Hemisphere temperature variability, but the contribution of the various methane sources and sinks to changes in concentration is still a matter of debate. This thesis assess changes in methane cycling over the past 160,000 years by measurements of the carbon isotopic composition d13C of methan...

Anthropogenic Biomes of the World, Version 2: 1700

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1700 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 1900

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1900 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 1800

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1800 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 2000

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 2000 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Methane emissions from a Californian landfill, determined from airborne remote sensing and in situ measurements

Directory of Open Access Journals (Sweden)

S. Krautwurst

2017-09-01

Full Text Available Fugitive emissions from waste disposal sites are important anthropogenic sources of the greenhouse gas methane (CH4. As a result of the growing world population and the recognition of the need to control greenhouse gas emissions, this anthropogenic source of CH4 has received much recent attention. However, the accurate assessment of the CH4 emissions from landfills by modeling and existing measurement techniques is challenging. This is because of inaccurate knowledge of the model parameters and the extent of and limited accessibility to landfill sites. This results in a large uncertainty in our knowledge of the emissions of CH4 from landfills and waste management. In this study, we present results derived from data collected during the research campaign COMEX (CO2 and MEthane eXperiment in late summer 2014 in the Los Angeles (LA Basin. One objective of COMEX, which comprised aircraft observations of methane by the remote sensing Methane Airborne MAPper (MAMAP instrument and a Picarro greenhouse gas in situ analyzer, was the quantitative investigation of CH4 emissions. Enhanced CH4 concentrations or CH4 plumes were detected downwind of landfills by remote sensing aircraft surveys. Subsequent to each remote sensing survey, the detected plume was sampled within the atmospheric boundary layer by in situ measurements of atmospheric parameters such as wind information and dry gas mixing ratios of CH4 and carbon dioxide (CO2 from the same aircraft. This was undertaken to facilitate the independent estimation of the surface fluxes for the validation of the remote sensing estimates. During the COMEX campaign, four landfills in the LA Basin were surveyed. One landfill repeatedly showed a clear emission plume. This landfill, the Olinda Alpha Landfill, was investigated on 4 days during the last week of August and first days of September 2014. Emissions were estimated for all days using a mass balance approach. The derived emissions vary between 11

METHANE INCORPORATION BY PROCARYOTIC PHOTOSYNTHETICMICROORGANISMS

Energy Technology Data Exchange (ETDEWEB)

Norton, Charles J.; Kirk, Martha; Calvin, Melvin

1970-08-01

The procaryotic photosynthetic microorganisms Anacystis nidulans, Nostoc and Rhodospirillum rubrum have cell walls and membranes that are resistant to the solution of methane in their lipid components and intracellular fluids. But Anacystis nidulans, possesses a limited bioxidant system, a portion of which may be extracellularly secreted, which rapidly oxidizes methane to carbon dioxide. Small C{sup 14} activities derived from CH{sub 4} in excess of experimental error are detected in all the major biochemical fractions of Anacystis nidulans and Nostoc. This limited capacity to metabolize methane appears to be a vestigial potentiality that originated over two billion years ago in the early evolution of photosynthetic bacteria and blue-green algae.

Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

Science.gov (United States)

Borowski, Marek; Kuczera, Zbigniew

2018-03-01

Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage) could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in the air; location

Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

Directory of Open Access Journals (Sweden)

Borowski Marek

2018-01-01

Full Text Available Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in

Abiotic Production of Methane in Terrestrial Planets

Science.gov (United States)

Guzmán-Marmolejo, Andrés; Escobar-Briones, Elva

2013-01-01

Abstract On Earth, methane is produced mainly by life, and it has been proposed that, under certain conditions, methane detected in an exoplanetary spectrum may be considered a biosignature. Here, we estimate how much methane may be produced in hydrothermal vent systems by serpentinization, its main geological source, using the kinetic properties of the main reactions involved in methane production by serpentinization. Hydrogen production by serpentinization was calculated as a function of the available FeO in the crust, given the current spreading rates. Carbon dioxide is the limiting reactant for methane formation because it is highly depleted in aqueous form in hydrothermal vent systems. We estimated maximum CH4 surface fluxes of 6.8×108 and 1.3×109 molecules cm−2 s−1 for rocky planets with 1 and 5 M⊕, respectively. Using a 1-D photochemical model, we simulated atmospheres with volume mixing ratios of 0.03 and 0.1 CO2 to calculate atmospheric methane concentrations for the maximum production of this compound by serpentinization. The resulting abundances were 2.5 and 2.1 ppmv for 1 M⊕ planets and 4.1 and 3.7 ppmv for 5 M⊕ planets. Therefore, low atmospheric concentrations of methane may be produced by serpentinization. For habitable planets around Sun-like stars with N2-CO2 atmospheres, methane concentrations larger than 10 ppmv may indicate the presence of life. Key Words: Serpentinization—Exoplanets—Biosignatures—Planetary atmospheres. Astrobiology 13, 550–559. PMID:23742231

Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases.

Science.gov (United States)

Zickfeld, Kirsten; Solomon, Susan; Gilford, Daniel M

2017-01-24

Mitigation of anthropogenic greenhouse gases with short lifetimes (order of a year to decades) can contribute to limiting warming, but less attention has been paid to their impacts on longer-term sea-level rise. We show that short-lived greenhouse gases contribute to sea-level rise through thermal expansion (TSLR) over much longer time scales than their atmospheric lifetimes. For example, at least half of the TSLR due to increases in methane is expected to remain present for more than 200 y, even if anthropogenic emissions cease altogether, despite the 10-y atmospheric lifetime of this gas. Chlorofluorocarbons and hydrochlorofluorocarbons have already been phased out under the Montreal Protocol due to concerns about ozone depletion and provide an illustration of how emission reductions avoid multiple centuries of future TSLR. We examine the "world avoided" by the Montreal Protocol by showing that if these gases had instead been eliminated in 2050, additional TSLR of up to about 14 cm would be expected in the 21st century, with continuing contributions lasting more than 500 y. Emissions of the hydrofluorocarbon substitutes in the next half-century would also contribute to centuries of future TSLR. Consideration of the time scales of reversibility of TSLR due to short-lived substances provides insights into physical processes: sea-level rise is often assumed to follow air temperature, but this assumption holds only for TSLR when temperatures are increasing. We present a more complete formulation that is accurate even when atmospheric temperatures are stable or decreasing due to reductions in short-lived gases or net radiative forcing.

Methane-oxidizing seawater microbial communities from an Arctic shelf

Science.gov (United States)

Uhlig, Christiane; Kirkpatrick, John B.; D'Hondt, Steven; Loose, Brice

2018-06-01

Marine microbial communities can consume dissolved methane before it can escape to the atmosphere and contribute to global warming. Seawater over the shallow Arctic shelf is characterized by excess methane compared to atmospheric equilibrium. This methane originates in sediment, permafrost, and hydrate. Particularly high concentrations are found beneath sea ice. We studied the structure and methane oxidation potential of the microbial communities from seawater collected close to Utqiagvik, Alaska, in April 2016. The in situ methane concentrations were 16.3 ± 7.2 nmol L-1, approximately 4.8 times oversaturated relative to atmospheric equilibrium. The group of methane-oxidizing bacteria (MOB) in the natural seawater and incubated seawater was > 97 % dominated by Methylococcales (γ-Proteobacteria). Incubations of seawater under a range of methane concentrations led to loss of diversity in the bacterial community. The abundance of MOB was low with maximal fractions of 2.5 % at 200 times elevated methane concentration, while sequence reads of non-MOB methylotrophs were 4 times more abundant than MOB in most incubations. The abundances of MOB as well as non-MOB methylotroph sequences correlated tightly with the rate constant (kox) for methane oxidation, indicating that non-MOB methylotrophs might be coupled to MOB and involved in community methane oxidation. In sea ice, where methane concentrations of 82 ± 35.8 nmol kg-1 were found, Methylobacterium (α-Proteobacteria) was the dominant MOB with a relative abundance of 80 %. Total MOB abundances were very low in sea ice, with maximal fractions found at the ice-snow interface (0.1 %), while non-MOB methylotrophs were present in abundances similar to natural seawater communities. The dissimilarities in MOB taxa, methane concentrations, and stable isotope ratios between the sea ice and water column point toward different methane dynamics in the two environments.

Turbulent burning rates of methane and methane-hydrogen mixtures

Energy Technology Data Exchange (ETDEWEB)

Fairweather, M. [School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Ormsby, M.P.; Sheppard, C.G.W. [School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Woolley, R. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

2009-04-15

Methane and methane-hydrogen (10%, 20% and 50% hydrogen by volume) mixtures have been ignited in a fan stirred bomb in turbulence and filmed using high speed cine schlieren imaging. Measurements were performed at 0.1 MPa (absolute) and 360 K. A turbulent burning velocity was determined for a range of turbulence velocities and equivalence ratios. Experimental laminar burning velocities and Markstein numbers were also derived. For all fuels the turbulent burning velocity increased with turbulence velocity. The addition of hydrogen generally resulted in increased turbulent and laminar burning velocity and decreased Markstein number. Those flames that were less sensitive to stretch (lower Markstein number) burned faster under turbulent conditions, especially as the turbulence levels were increased, compared to stretch-sensitive (high Markstein number) flames. (author)

Could Methane Oxidation in Lakes Be Enhanced by Eutrophication?

Science.gov (United States)

Van Grinsven, S.; Villanueva, L.; Harrison, J.; S Sinninghe Damsté, J.

2017-12-01

Climate change and eutrophication both affect aquatic ecosystems. Eutrophication is caused by high nutrient inputs, leading to algal blooms, oxygen depletion and disturbances of the natural balances in aquatic systems. Methane, a potent greenhouse gas produced biologically by anaerobic degradation of organic matter, is often released from the sediments of lakes and marine systems to overlying water and the atmosphere. Methane oxidation, a microbial methane consumption process, can limit methane emission from lakes and reservoirs by 50-80%. Here, we studied methane oxidation in a seasonally stratified reservoir: Lacamas Lake in Washington, USA. We found this lake has a large summer storage capacity of methane in its deep water layer, with a very active microbial community capable of oxidizing exceptionally high amounts of methane. The natural presence of terminal electron acceptors is, however, too low to support these high potential rates. Addition of eutrophication-related nutrients such as nitrate and sulfate increased the methane removal rates by 4 to 7-fold. The microbial community was studied using 16S rRNA gene amplicon sequencing and preliminary results indicate the presence of a relatively unknown facultative anaerobic methane oxidizer of the genus Methylomonas, capable of using nitrate as an electron donor. Experiments in which anoxic and oxic conditions were rapidly interchanged showed this facultative anaerobic methane oxidizer has an impressive flexibility towards large, rapid changes in environmental conditions and this feature might be key to the unexpectedly high methane removal rates in eutrophied and anoxic watersheds.

Methanization - Technical sheet

International Nuclear Information System (INIS)

Bastide, Guillaume

2015-02-01

This document explains fundamentals of methanization such as biological reactions and conditions suitable for biogas production (temperature, pH, anaerobic medium, and so on). It also proposes an overview of available techniques, of the present regulation, of environmental impacts, and of costs and profitability of methanization installations. Examples of installations are provided, as well as a set of questions and answers. Perspectives of development are finally discussed in terms of sector development potential, of regulatory evolution, of new perspectives for gas valorisation, of need of acquisition of reference data due to the relatively low number of existing installations, and of research and development

Phytoremediation of Atmospheric Methane

Science.gov (United States)

2013-04-15

REPORT Phytoremediation of Atmospheric Methane 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: We have transformed a plant, Arabidopsis thaliana, with the...298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - 31-Mar-2012 Phytoremediation of Atmospheric Methane Report Title ABSTRACT We have transformed a...DD882) Scientific Progress See attachment Technology Transfer 1    Final Report for DARPA project W911NF1010027  Phytoremediation  of Atmospheric

Anthropogenic effect on avalanche and debris flow activity

OpenAIRE

S. A. Sokratov; Yu. G. Seliverstov; A. L. Shnyparkov; K. P. Koltermann

2013-01-01

The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoida...

Template-Assisted Wet-Combustion Synthesis of Fibrous Nickel-Based Catalyst for Carbon Dioxide Methanation and Methane Steam Reforming.

Science.gov (United States)

Aghayan, M; Potemkin, D I; Rubio-Marcos, F; Uskov, S I; Snytnikov, P V; Hussainova, I

2017-12-20

Efficient capture and recycling of CO 2 enable not only prevention of global warming but also the supply of useful low-carbon fuels. The catalytic conversion of CO 2 into an organic compound is a promising recycling approach which opens new concepts and opportunities for catalytic and industrial development. Here we report about template-assisted wet-combustion synthesis of a one-dimensional nickel-based catalyst for carbon dioxide methanation and methane steam reforming. Because of a high temperature achieved in a short time during reaction and a large amount of evolved gases, the wet-combustion synthesis yields homogeneously precipitated nanoparticles of NiO with average particle size of 4 nm on alumina nanofibers covered with a NiAl 2 O 4 nanolayer. The as-synthesized core-shell structured fibers exhibit outstanding activity in steam reforming of methane and sufficient activity in carbon dioxide methanation with 100% selectivity toward methane formation. The as-synthesized catalyst shows stable operation under the reaction conditions for at least 50 h.

Sources of anthropogenic radionuclides in the environment: a review

International Nuclear Information System (INIS)

Hu Qinhong; Weng Jianqing; Wang Jinsheng

2010-01-01

Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview on sources of anthropogenic radionuclides in the environment, as well as a brief discussion of salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current developments that have lead, or could potentially contribute, to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) uranium mining and milling; (5) commercial fuel reprocessing; (6) geological repository of high-level nuclear wastes that include radionuclides might be released in the future, and (7) nuclear accidents. Then, we briefly summarize the inventory of radionuclides 99 Tc and 129 I, as well as geochemical behavior for radionuclides 99 Tc, 129 I, and 237 Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment; biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

Experimental study of methanic fermentation of straw

Energy Technology Data Exchange (ETDEWEB)

Dopter, P; Beerens, H

1952-12-03

The amount of liquid manure obtainable was a limiting factor in methanic fermentation of wheat straw. An equal volume of 0.2% aqueous solution of Na formate could be substituted for 90% of the normal requirements of liquid manure. This shortened the preliminary stages of cellulosic fermentation when no methane was produced and slightly increased the subsequent yield of methane.

METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 15: GAS-ASSISTED GLYCOL PUMPS

Science.gov (United States)

The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

Clumped isotope effects during OH and Cl oxidation of methane

DEFF Research Database (Denmark)

Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan Albrecht

2017-01-01

A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH was produ......A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH...... effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE...... reactions. In a closed system, however, this effect is overtaken by the large D/H isotope effect, which causes the residual methane to become anti-clumped relative to the initial methane. Based on these results, we demonstrate that oxidation of methane by OH, the predominant oxidant for tropospheric methane...

Validation of landfill methane measurements from an unmanned aerial system

DEFF Research Database (Denmark)

Allen, Grant; Williams, Paul; Ricketts, hugo

Landfill gas is made up of roughly equal amounts of methane and carbon dioxide. Modern UK landfills capture and use much of the methane gas as a fuel. But some methane escapes and is emitted to the atmosphere. Methane is an important greenhouse gas and controls on methane emissions are a part...... of international and national strategies to limit climate change. Better estimates of methane emissions from landfills and other similar sources would allow the UK to improve the quantification and control of greenhouse gas emissions. This project tested the accuracy of methane measurement using an unmanned aerial...

Handbook methane potential; Handbok metanpotential

Energy Technology Data Exchange (ETDEWEB)

Carlsson, My (AnoxKaldnes AB (Sweden)); Schnurer, Anna (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden))

2011-07-15

Before using a organic material for biogas production it is essential to evaluate the methane production potential. The methane potential is one important tool possible to use during planning of new plants but also when new materials are considered for already running biogas plants. The chemical composition of different organic material varies extensively and this will have an impact on both the degradability and the methane potential. Information about the methane potential of a specific material can sometimes be found in the literature or can be calculated after a chemical/ physical or biological characterization. Here, the BMP test (Biochemical Methane Potential) is a commonly used method. Today the BMP test is a commonly used method to determine the methane potential. Many national and international research groups, consultants as well as personal at biogas plants are using this method and there is a lot of data available in the literature from such tests. In addition there are several protocols giving guidelines on how to execute a BMP-test. The BMP-test is performed in many different ways, not always under optimized conditions, and there is a lack of information on how to interpret the obtained data. This report summarizes knowledge from the literature and the experience from a Swedish referee group, consisting of persons being active performers of BMP-tests. The report does not include a standardized protocol as the procedure can be performed in different ways depending on available equipment and on the type of material to be tested. Instead the report discusses different factors of great importance for a successful test giving reliable results. The report also summarizes important information concerning the interpretation and how to present results in order to allow comparison of data from different test.

Feasibility of atmospheric methane removal using methanotrophic biotrickling filters.

Science.gov (United States)

Yoon, Sukhwan; Carey, Jeffrey N; Semrau, Jeremy D

2009-07-01

Methane is a potent greenhouse gas with a global warming potential ~23 times that of carbon dioxide. Here, we describe the modeling of a biotrickling filtration system composed of methane-consuming bacteria, i.e., methanotrophs, to assess the utility of these systems in removing methane from the atmosphere. Model results indicate that assuming the global average atmospheric concentration of methane, 1.7 ppmv, methane removal is ineffective using these methanotrophic biofilters as the methane concentration is too low to enable cell survival. If the concentration is increased to 500-6,000 ppmv, however, similar to that found above landfills and in concentrated animal feeding operations (factory farms), 4.98-35.7 tons of methane can be removed per biofilter per year assuming biotrickling filters of typical size (3.66 m in diameter and 11.5 m in height). Using reported ranges of capital, operational, and maintenance costs, the cost of the equivalent ton of CO(2) removal using these systems is $90-$910 ($2,070-$20,900 per ton of methane), depending on the influent concentration of methane and if heating is required. The use of methanotrophic biofilters for controlling methane emissions is technically feasible and, provided that either the costs of biofilter construction and operation are reduced or the value of CO(2) credits is increased, can also be economically attractive.

Potential for reduction of methane emissions from dairy cows

DEFF Research Database (Denmark)

Johannes, Maike; Hellwing, Anne Louise Frydendahl; Lund, Peter

2010-01-01

Methane is a gas cows naturally produce in the rumen. However, it is also a potential greenhouse gas. Therefore, there is a certain interest from an environmental point of view to reduce methane emissions from dairy cows. Estimates from earlier studies indicate that there is a potential to reduce...... methane production by 10 to 25% by changing the feeding strategies. Several feedstuffs influence methane production, such as additional fat. The increase of the concentrate proportion can potentially decrease methane by decreasing the rumen degradability of the diet or by changing the rumen fermentation......, while fibre and sugar enhance methane emissions. Fat can be regarded as the most promising feed additive at the moment. At AU, respiration chambers have been installed to enable methane measurements from dairy cows combined with digestibility trials, and at present studies are being conducted concerning...

Methanation of Carbon Dioxide

OpenAIRE

Goodman, Daniel Jacob

2013-01-01

The emission of greenhouse gases into the atmosphere has been linked to global warming. Carbon dioxide's (CO2) one of the most abundant greenhouse gases. Natural gas, mainly methane, is the cleanest fossil fuel for electricity production helping meet the United States ever growing energy needs. The methanation of CO2 has the potential to address both of these problems if a catalyst can be developed that meets the activity, economic and environmental requirements to industrialize the process. ...

High-pressure raman study on single crystalline methane hydrate surrounded by methane in a diamond anvil cell

International Nuclear Information System (INIS)

Ohno, Y; Sasaki, S; Kume, T; Shimizu, H

2008-01-01

High-pressure Raman measurements have been performed for single crystalline methane hydrate (MH) surrounded by fluid or solid methane in a diamond anvil cell. We successfully obtained the pure O-H stretching and lattice vibration spectra in MH-sI and MH-II phases. In these Raman spectra, there is no Raman band from water or ice-VI. The observed pressure of phase transformation from MH-sI to MH-II is 0.9 GPa, which is the same result as methane hydrate surrounded by water

Enteric methane emissions from German pigs

DEFF Research Database (Denmark)

Dämmgen, Ulrich; Schulz, Joachim; Klausing, Heinrich Kleine

2012-01-01

Methane emissions from enteric fermentation of pigs are object of emission reporting. Hitherto they were treated as part of the energy balance of pigs, in accordance with IPCC guidance documents. They were calculated from the gross energy intake rate and a constant methane conversion ratio....... Meanwhile numerous experimental data on methane emissions from enteric fermentation is available in Germany and abroad; the results are compiled in this work. These results also allow for a description of transformation processes in the hind gut and a subsequent establishment of models that relate emissions...... to feed and performance data. The model by Kirchgeßner et al. (1995) is based on German experimental data and reflects typical national diet compositions. It is used to quantify typical emissions and methane conversion ratios. The results agree with other experimental findings at home and abroad...

Bioelectrochemical approach for control of methane emission from wetlands.

Science.gov (United States)

Liu, Shentan; Feng, Xiaojuan; Li, Xianning

2017-10-01

To harvest electricity and mitigate methane emissions from wetlands, a novel microbial fuel cell coupled constructed wetland (MFC-CW) was assembled with an anode placing in the rhizosphere and a cathode on the water surface. Plant-mediated methane accounted for 71-82% of the total methane fluxes. The bioanode served as an inexhaustible source of electron acceptors and resulted in reduced substantial methane emissions owing to electricigens outcompeting methanogens for carbon and electrons when substrate was deficient. However, when supplying sufficient organic carbon, both electricity and methane increased, indicating that electrogenesis and methanogenesis could co-exist in harmony. Direct methane emission (diffusion/ebullition) and plant-mediated methane emission were affected by operating conditions. Methanogenesis was significantly suppressed (∼98%) at HRT of 96h and with external resistance of 200Ω, accompanied with improved coulombic efficiency of 14.9% and current density of 187mA/m 2 . Contrarily, change of electrode polarity in the rhizosphere led to more methane efflux. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trace methane oxidation studied in several Euryarchaeota under diverse conditions

Directory of Open Access Journals (Sweden)

James J. Moran

2005-01-01

Full Text Available We used 13C-labeled methane to document the extent of trace methane oxidation by Archaeoglobus fulgidus, Archaeoglobus lithotrophicus, Archaeoglobus profundus, Methanobacterium thermoautotrophicum, Methanosarcina barkeri and Methanosarcina acetivorans. The results indicate trace methane oxidation during growth varied among different species and among methanogen cultures grown on different substrates. The extent of trace methane oxidation by Mb. thermoautotrophicum (0.05 ± 0.04%, ± 2 standard deviations of the methane produced during growth was less than that by M. barkeri (0.15 ± 0.04%, grown under similar conditions with H2 and CO2. Methanosarcina acetivorans oxidized more methane during growth on trimethylamine (0.36 ± 0.05% than during growth on methanol (0.07 ± 0.03%. This may indicate that, in M. acetivorans, either a methyltransferase related to growth on trimethylamine plays a role in methane oxidation, or that methanol is an intermediate of methane oxidation. Addition of possible electron acceptors (O2, NO3–, SO22–, SO32– or H2 to the headspace did not substantially enhance or diminish methane oxidation in M. acetivorans cultures. Separate growth experiments with FAD and NAD+ showed that inclusion of these electron carriers also did not enhance methane oxidation. Our results suggest trace methane oxidized during methanogenesis cannot be coupled to the reduction of these electron acceptors in pure cultures, and that the mechanism by which methane is oxidized in methanogens is independent of H2 concentration. In contrast to the methanogens, species of the sulfate-reducing genus Archaeoglobus did not significantly oxidize methane during growth (oxidizing 0.003 ± 0.01% of the methane provided to A. fulgidus, 0.002 ± 0.009% to A. lithotrophicus and 0.003 ± 0.02% to A. profundus. Lack of observable methane oxidation in the three Archaeoglobus species examined may indicate that methyl-coenzyme M reductase, which is not present in

Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget

Science.gov (United States)

Wahlen, Martin

1994-01-01

The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

Science.gov (United States)

Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

2015-04-01

Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

Global diffusive fluxes of methane in marine sediments

NARCIS (Netherlands)

Egger, M.; Riedinger, N.; Mogollón, J.M.; Jørgensen, B.B.

2018-01-01

Anaerobic oxidation of methane provides a globally important, yet poorly constrained barrier for the vast amounts of methane produced in the subseafloor. Here we provide a global map and budget of the methane flux and degradation in diffusion-controlled marine sediments in relation to the depth of

Estimating historical landfill quantities to predict methane emissions

NARCIS (Netherlands)

Lyons, S.; Murphy, L.; Tol, R.S.J.

2010-01-01

There are no observations for methane emissions from landfill waste in Ireland. Methane emissions are imputed from waste data. There are intermittent data on waste sent to landfill. We compare two alternative ways to impute the missing waste " data" and evaluate the impact on methane emissions. We

Anthropogenic infrastructure as a component of urbogeosystems

Directory of Open Access Journals (Sweden)

Oleksii Chuiev

2017-11-01

Full Text Available This article deals with the definition of the concept of "anthropogenic infrastructure" and attempts to find its place in the structure of urbogeosystems. The concept itself can not be called new, as many foreign authors have already used it, but the final definition never happened. The reasons why city studies are becoming more relevant in the face of ever-accelerating urbanization are briefly presented. Prerequisites for the emergence of the urban environment and approaches to its study are given. A special attention is paid to the consideration of urbosystems and their component structure. The main four components are described, which include the technosphere, biosphere, population and abiotic nature. The causes of the appearance of urban ecosystems and their specific features are analyzed. Based on the deficiencies of the "Urbosphere", "Urbosystem" and "Urboecosystem", the notion of "Urbogeosystem" is formed once again. Since architectural and construction objects are key components of such systems, their integration into anthropogenic infrastructure allows us to operate with a more general concept. Functional zones of the city, which are part of the anthropogenic infrastructure, are described. These include residential, industrial, forest and park areas. Examples of the use and functioning of each of the zones are given. An attempt has been made to estimate the boundaries of urbogeosystems. The existing approaches to the classification of anthropogenic infrastructure are analyzed. For one of them, it is advisable to allocate separately "hard" and "soft" infrastructure by the nature of the tasks of society, which they are called upon to satisfy. An alternative approach is to divide the anthropogenic infrastructure into "human" and "physical" ones. If the first satisfies the socio-cultural needs of people, the second is used for production, development, establishment of communications, transportation. It is proved why it is expedient to

First retrievals of methane isotopologues from FTIR ground-based observations

Science.gov (United States)

Bader, Whitney; Strong, Kimberly; Walker, Kaley; Buzan, Eric

2017-04-01

Atmospheric methane concentrations have reached a new high at 1845 ± 2 ppb, accounting for an increase of 256 % since pre-industrial times (WMO, 2016). In the last ten years, methane has been on the rise again at rates of ˜0.3%/year (e.g., Bader et al., 2016), after a period of stabilization of about 5 years. This recent increase is not fully understood due to remaining uncertainties in the methane budget, influenced by numerous anthropogenic and natural emission sources. In order to examine the cause(s) of this increase, we focus on the two main methane isotopologues, i.e. CH3D and 13CH4. Both CH3D and 13CH4 are emitted in the atmosphere with different ratio depending on the emission processes involved. As heavier isotopologues will react more slowly than 12CH4, each isotopologue will be depleted from the atmosphere at a specific rate depending on the removal process. Methane isotopologues are therefore good tracers of the methane budget. In this contribution, the first development and optimization of the retrieval strategy of CH3D as well as the preliminary tests for 13CH4 will be presented and discussed , using FTIR (Fourier Transform infrared) solar spectra collected at the Eureka (80.05 ˚ N, -86.42 ˚ E, 610 m a.s.l.) and Toronto (43.66˚ N, -79.4˚ E, 174 m a.s.l.) ground-based sites. Mixing ratio vertical profiles from a Whole Atmosphere Community Climate Model (WACCM v.4, Marsh et al., 2013) simulation developed by Buzan et al. (2016) are used as a priori inputs. A discussion on the type of regularization constraints used for the retrievals will be presented as well as an evaluation of available spectroscopy (primarily the different editions of the HITRAN database, see Rothman et al., 2013 and references therein). The uncertainties affecting the retrieved columns as well as information content evaluation will be discussed in order to assess the best strategy to be employed based on its altitude sensitivity range and complete error budget. Acknowledgments

Permeability of sediment cores from methane hydrate deposit in the Eastern Nankai Trough, Japan

Science.gov (United States)

Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

2013-12-01

Effective and absolute permeability are key parameters for gas production from methane-hydrate-bearing sandy sediments. Effective and/or absolute permeability have been measured using methane-hydrate-bearing sandy cores and clayey and silty cores recovered from Daini Atsumi Knoll in the Eastern Nankai Trough during the 2012 JOGMEC/JAPEX Pressure coring operation. Liquid-nitrogen-immersed cores were prepared by rapid depressurization of pressure cores recovered by a pressure coring system referred to as the Hybrid PCS. Cores were shaped cylindrically on a lathe with spraying of liquid nitrogen to prevent hydrate dissociation. Permeability was measured by a flooding test or a pressure relaxation method under near in-situ pressure and temperature conditions. Measured effective permeability of hydrate-bearing sediments is less than tens of md, which are order of magnitude less than absolute permeability. Absolute permeability of clayey cores is approximately tens of μd, which would perform a sealing function as cap rocks. Permeability reduction due to a swelling effect was observed for a silty core during flooding test of pure water mimicking hydrate-dissociation-water. Swelling effect may cause production formation damage especially at a later stage of gas production from methane hydrate deposits. This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program conducted by the Ministry of Economy, Trade and Industry (METI).

Global Methane Biogeochemistry

Science.gov (United States)

Reeburgh, W. S.

2003-12-01

Methane (CH4) has been studied as an atmospheric constituent for over 200 years. A 1776 letter from Alessandro Volta to Father Campi described the first experiments on flammable "air" released by shallow sediments in Lake Maggiore (Wolfe, 1996; King, 1992). The first quantitative measurements of CH4, both involving combustion and gravimetric determination of trapped oxidation products, were reported in French by Boussingault and Boussingault, 1864 and Gautier (1901), who reported CH4 concentrations of 10 ppmv and 0.28 ppmv (seashore) and 95 ppmv (Paris), respectively. The first modern measurements of atmospheric CH4 were the infrared absorption measurements of Migeotte (1948), who estimated an atmospheric concentration of 2.0 ppmv. Development of gas chromatography and the flame ionization detector in the 1950s led to observations of vertical CH4 distributions in the troposphere and stratosphere, and to establishment of time-series sampling programs in the late 1970s. Results from these sampling programs led to suggestions that the concentration of CH4, as that of CO2, was increasing in the atmosphere. The possible role of CH4 as a greenhouse gas stimulated further research on CH4 sources and sinks. Methane has also been of interest to microbiologists, but findings from microbiology have entered the larger context of the global CH4 budget only recently.Methane is the most abundant hydrocarbon in the atmosphere. It plays important roles in atmospheric chemistry and the radiative balance of the Earth. Stratospheric oxidation of CH4 provides a means of introducing water vapor above the tropopause. Methane reacts with atomic chlorine in the stratosphere, forming HCl, a reservoir species for chlorine. Some 90% of the CH4 entering the atmosphere is oxidized through reactions initiated by the OH radical. These reactions are discussed in more detail by Wofsy (1976) and Cicerone and Oremland (1988), and are important in controlling the oxidation state of the atmosphere

Enteric methane emissions from German dairy cows

DEFF Research Database (Denmark)

Dammgen, U; Rosemann, C; Haenel, H D

2012-01-01

Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

Greenhouse effect contributions of US landfill methane

International Nuclear Information System (INIS)

Augenstein, D.

1991-01-01

The greenhouse effect has recently been receiving a great deal of scientific and popular attention. The term refers to a cause-and-effect relationship in which ''heat blanketing'' of the earth, due to trace gas increases in the atmosphere, is expected to result in global warming. The trace gases are increasing as the result of human activities. Carbon dioxide (CO 2 ) is the trace gas contributing most importantly to the ''heat blanketing'' and currently receives the most attention. Less widely recognized has been the high importance of methane (CH 4 ). Methane's contribution to the increased heat blanketing occurring since 1980 is estimated to be over a third as much as that of carbon dioxide. Gas from landfills has in turn been recognized to be a source of methane to the atmospheric buildup. However the magnitude of the landfill methane contribution, and the overall significance of landfill methane to the greenhouse phenomenon has been uncertain and the subject of some debate. (Author)

Decarbonisation of fossil energy via methane pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Kreysa, G.; Agar, D.W.; Schultz, I. [Technische Univ. Dortmund (Germany)

2010-12-30

Despite the rising consumption of energy over the last few decades, the proven reserves of fossil fuels have steadily increased. Additionally, there are potentially tremendous reserves of methane hydrates available, which remain to be exploited. The use of fossil energy sources is thus increasingly being dictated less by supply than by the environmental concerns raised by climate change. In the context of the decarbonisation of the global energy system that this has stimulated, new means must be explored for using methane as energy source. Noncatalytic thermal pyrolysis of methane is proposed here as a promising concept for utilising methane with low to zero carbon dioxide emissions. Following cracking, only the energy content of the hydrogen is used, while the carbon can be stored safely and retrievably in disused coal mines. The thermodynamics and different process engineering concepts for the technical realisation of such a carbon moratorium technology are discussed. The possible contribution of methane pyrolysis to carbon negative geoengineering is also addressed. (orig.)

Effect of bubble size and density on methane conversion to hydrate

Energy Technology Data Exchange (ETDEWEB)

Leske, J.; Taylor, C.E.; Ladner, E.P.

2007-03-01

Research is underway at NETL to understand the physical properties of methane hydrates. One area of investigation is the storage of methane as methane hydrates. An economical and efficient means of storing methane in hydrates opens many commercial opportunities such as transport of stranded gas, off-peak storage of line gas, etc.We have observed during our investigations that the ability to convert methane to methane hydrate is enhanced by foaming of the methane–water solution using a surfactant. The density of the foam, along with the bubble size, is important in the conversion of methane to methane hydrate.

Removal of methane from compressed natural gas fueled vehicle exhaust

International Nuclear Information System (INIS)

Subramanian, S.; Kudla, R.J.; Chattha, M.S.

1992-01-01

The objective of this paper is to investigate the modes of methane (CH 4 ) removal from simulated compressed natural gas (CNG) fueled vehicle exhaust under net oxidizing, net reducing, and stoichiometric conditions. Model reaction studies were conducted. The results suggest that the oxidation of methane with oxygen contributes to the removal of methane under net oxidizing conditions. In contrast, the oxidation of methane with oxygen as well as nitric oxide contributes to its removal under net reducing conditions. The steam reforming reaction does not significantly contribute to the removal of methane. The methane conversions under net reducing conditions are higher than those observed under net oxidizing conditions. The study shows that the presence of carbon monoxide in the feed gas leads to a gradual decrease in the methane conversion with increasing redox ratio, under net oxidizing conditions. a minimum in methane conversion is observed at a redox ratio of 0. 8. The higher activity for the methane-oxygen reaction resulting from a lowering in the overall oxidation state of palladium and the contribution of the methane-nitric oxide reaction toward the removal of CH 4 appear to account for the higher CH 4 conversions observed under net reducing conditions

Application of a methane carbon isotope analyzer for the investigation of δ13C of methane emission measured by the automatic chamber method in an Arctic Tundra

Science.gov (United States)

Mastepanov, Mikhail; Christensen, Torben

2014-05-01

Methane emissions have been monitored by an automatic chamber method in Zackenberg valley, NE Greenland, since 2006 as a part of Greenland Ecosystem Monitoring (GEM) program. During most of the seasons the measurements were carried out from the time of snow melt (June-July) until freezing of the active layer (October-November). Several years of data, obtained by the same method, instrumentation and at exactly the same site, provided a unique opportunity for the analysis of interannual methane flux patterns and factors affecting their temporal variability. The start of the growing season emissions was found to be closely related to a date of snow melt at the site. Despite a large between year variability of this date (sometimes more than a month), methane emission started within a few days after, and was increasing for the next about 30 days. After this peak of emission, it slowly decreased and stayed more or less constant or slightly decreasing during the rest of the growing season (Mastepanov et al., Biogeosciences, 2013). During the soil freezing, a second peak of methane emission was found (Mastepanov et al., Nature, 2008); its amplitude varied a lot between the years, from almost undetectable to comparable with total growing season emissions. Analysis of the multiyear emission patterns (Mastepanov et al., Biogeosciences, 2013) led to hypotheses of different sources for the spring, summer and autumn methane emissions, and multiyear cycles of accumulation and release of these components to the atmosphere. For the further investigation of this it was decided to complement the monitoring system with a methane carbon isotope analyzer (Los Gatos Research, USA). The instrument was installed during 2013 field season and was successfully operating until the end of the measurement campaign (27 October). Detecting both 12C-CH4 and 13C-CH4 concentrations in real time (0.5 Hz) during automatic chamber closure (15 min), the instrument was providing data for determination of

methanization development in Ile-de-France - Ile-de-France region. Synthesis. The Regional Council strategy for methanization development

International Nuclear Information System (INIS)

2013-06-01

A first document reports the study of methanization development in the Ile-de-France region by addressing biomass produced on the region territory. It aimed at identifying and assessing the existing and potential physical resource while introducing mobilisation rates in order to define different scenarios. A situational analysis of operated and projected methanization installations has also been performed. These projects have been classified according to a typology, and analysed according to the proposed scenarios. The position of methanization with respect to other biomass valorisation sectors, as well as the impact of mobilisation with respect to a return-to-soil of organic matters have also been discussed. A second document proposes a synthetic version of this study. The third document presents the Regional Council's policy and strategy regarding methanization development: challenges and prospective scenarios, importance of a sustainable methanization at the service of territory development, regulation for a call for projects, project assessment and selection, project footprint, inputs qualities and supplies, energetic and agronomic valorisation, and grid for project analysis. An appendix contains a synthetic version of the first document

Discriminating background from anthropogenic lead by isotopic methods

International Nuclear Information System (INIS)

Nelson, B.K.; O'Brien, H.E.

1995-01-01

The goal of this pilot project was to evaluate the practicality of using natural variations in the isotopic composition of lead to test for the presence of anthropogenic lead in soil, surface water and ground water. Complex chemical reactions in the environment may cause measured lead concentrations to be ambiguous indicators of anthropogenic lead component. The lead isotope tracer technique has the potential to identify both the presence and proportion of anthropogenic lead in the environment. The tested the lead isotope technique at Eielson Air Force Base, Alaska, on sources of suspected fuel contamination. Although the results are specific to this base, the general technique of using lead isotopes to trace the movement of anthropogenic lead is applicable to other CERCLA sites. The study had four objectives: (1) characterize the natural lead isotope composition of bedrock, stream sediment and soils; (2) characterize the isotopic composition of the contaminant lead derived from fuel; (3) evaluate the sensitivity of the isotopic method to distinguishing between anthropogenic and natural lead in soil and water samples and (4) evaluate the analytical feasibility and accuracy of the method at the Isotope Geochemistry Laboratory at the University of Washington

Methane storage capacity of the early martian cryosphere

Science.gov (United States)

Lasue, Jeremie; Quesnel, Yoann; Langlais, Benoit; Chassefière, Eric

2015-11-01

Methane is a key molecule to understand the habitability of Mars due to its possible biological origin and short atmospheric lifetime. Recent methane detections on Mars present a large variability that is probably due to relatively localized sources and sink processes yet unknown. In this study, we determine how much methane could have been abiotically produced by early Mars serpentinization processes that could also explain the observed martian remanent magnetic field. Under the assumption of a cold early Mars environment, a cryosphere could trap such methane as clathrates in stable form at depth. The extent and spatial distribution of these methane reservoirs have been calculated with respect to the magnetization distribution and other factors. We calculate that the maximum storage capacity of such a clathrate cryosphere is about 2.1 × 1019-2.2 × 1020 moles of CH4, which can explain sporadic releases of methane that have been observed on the surface of the planet during the past decade (∼1.2 × 109 moles). This amount of trapped methane is sufficient for similar sized releases to have happened yearly during the history of the planet. While the stability of such reservoirs depends on many factors that are poorly constrained, it is possible that they have remained trapped at depth until the present day. Due to the possible implications of methane detection for life and its influence on the atmospheric and climate processes on the planet, confirming the sporadic release of methane on Mars and the global distribution of its sources is one of the major goals of the current and next space missions to Mars.

Reaction between infusion water and methane

Energy Technology Data Exchange (ETDEWEB)

Ettinger, I L

1977-09-01

This paper discusses the effect of infused water on the initial gas emission rate and on the pore structure of the coal. Water traps methane in micro-pores, so that lengthy periods are needed for the methane to penetrate large voids and cavities.

Formation temperatures of thermogenic and biogenic methane

Science.gov (United States)

Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, Anna M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

2014-01-01

Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

Natural and anthropogenic radionuclide activity concentrations in the New Zealand diet

International Nuclear Information System (INIS)

Pearson, Andrew J.; Gaw, Sally; Hermanspahn, Nikolaus; Glover, Chris N.

2016-01-01

To support New Zealand's food safety monitoring regime, a survey was undertaken to establish radionuclide activity concentrations across the New Zealand diet. This survey was undertaken to better understand the radioactivity content of the modern diet and also to assess the suitability of the current use of milk as a sentinel for dietary radionuclide trends. Thirteen radionuclides were analysed in 40 common food commodities, including animal products, fruits, vegetables, cereal grains and seafood. Activity was detected for 137 Caesium, 90 Strontium and 131 Iodine. No other anthropogenic radionuclides were detected. Activity concentrations of the three natural radionuclides of Uranium and the daughter radionuclide 210 Polonium were detected in the majority of food sampled, with a large variation in magnitude. The maximum activity concentrations were detected in shellfish for all these radionuclides. Based on the established activity concentrations and ranges, the New Zealand diet contains activity concentrations of anthropogenic radionuclides far below the Codex Alimentarius guideline levels. Activity concentrations obtained for milk support its continued use as a sentinel for monitoring fallout radionuclides in terrestrial agriculture. The significant levels of natural and anthropogenic radionuclide activity concentrations detected in finfish and molluscs support undertaking further research to identify a suitable sentinel for New Zealand seafood monitoring. - Highlights: • A radionuclide monitoring program was undertaken across the New Zealand food supply. • 40 food types were analysed for 13 radionuclides. • 137 Cs was present in 15% of foods (range: 0.05–0.44Bq/kg). • Anthropogenic radionuclides displayed compliance with international limits. • 210 Po, 234 U and 238 U were present in most foods with large ranges of activities.

Bacterial overgrowth and methane production in children with encopresis.

Science.gov (United States)

Leiby, Alycia; Mehta, Devendra; Gopalareddy, Vani; Jackson-Walker, Susan; Horvath, Karoly

2010-05-01

To assess the prevalence of small intestinal bacterial overgrowth (SIBO) and methane production in children with encopresis. Radiographic fecal impaction (FI) scores were assessed in children with secondary, retentive encopresis and compared with the breath test results. Breath tests with hypoosmotic lactulose solution were performed in both the study patients (n = 50) and gastrointestinal control subjects (n = 39) groups. The FI scores were significantly higher in the patients with encopresis who were methane producers (P encopresis and 9 of 39 (23%) of control subjects (P = .06). Methane was produced in 56% of the patients with encopresis versus 23.1% of the control subjects in the gastrointestinal group (P encopresis had a higher prevalence of SIBO, elevated basal methane levels, and higher methane production. Methane production was associated with more severe colonic impaction. Further study is needed to determine whether methane production is a primary or secondary factor in the pathogenesis of SIBO and encopresis.

FY1995 molecular control technology for mining of methane-gas-hydrate; 1995 nendo methane hydrate no bunshi seigyo mining

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The objectives of the investigation are as follows: 1) developing a method to control formation/dissociation of methane-gas-hydrate, 2) developing a technology to displace methane gas by CO{sub 2} in methane-gas-hydrate deposit, 3) developing a technology to produce methane gas from the deposit efficiently. The final purpose of the project is to create new mining industry that solves both the problems of energy and global environment. 1) Clustering of water molecules is found to play the key role in the methane gas hydrate formation. 2) Equilibrium properties and kinetics of gas hydrates formation and dissociation in bulk-scale gas-hydrate are clarified in the practical environmental conditions. 3) Particle size of hydrate deposit influences the formation and dissociation of bulk-scale gas-hydrate crystal. 4) Mass transfer between gas and liquid phase in turbulent bubbly flow is a function of bubble diameter. The mass transfer depends on interfacial dynamics. (NEDO)

Heterogeneous Nucleation of Methane Hydrate in a Water-Decane-Methane Emulsion

Science.gov (United States)

Shestakov, V. A.; Kosyakov, V. I.; Manakov, A. Yu.; Stoporev, A. S.; Grachev, E. V.

2018-07-01

Heterogeneous nucleation in disperse systems with metastable disperse phases plays an important role in the mechanisms of environmental and technological processes. The effect the concentration and activity of particles that initiate the formation of a new phase have on nucleation processes in such systems is considered. An approach is proposed that allows construction of a spectrum of particle activity characterizing the features of nucleation in a sample, based on the fraction of crystallized droplets depending on the level of supercooling and the use of Weibull's distribution. The proposed method is used to describe experimental data on the heterogeneous nucleation of methane hydrate in an emulsion in a water-decane-methane system.

Factors Controlling Methane in Arctic Lakes of Southwest Greenland.

Science.gov (United States)

Northington, Robert M; Saros, Jasmine E

2016-01-01

We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the northern hemisphere (125 μmol L-1). The most important factors influencing methane in Greenland lakes included ionic composition (SO4, Na, Cl) and chlorophyll a in the water column. DOC concentrations were also related to methane, but the short length of the study likely underestimated the influence and timing of DOC on methane concentrations in the region. Atmospheric methane concentrations are increasing globally, with freshwater ecosystems in northern latitudes continuing to serve as potentially large sources in the future. Much less is known about how freshwater lakes in Greenland fit in the global methane budget compared to other, more well-studied areas of the Arctic, hence our work provides essential data for a more complete view of this rapidly changing region.

Initial results of detected methane emissions from landfills in the Los Angeles Basin during the COMEX campaign by the Methane Airborne MAPper (MAMAP) instrument and a greenhouse gas in-situ analyser

Science.gov (United States)

Krautwurst, Sven; Gerilowski, Konstantin; Kolyer, Richard; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Vigil, Sam; Buchwitz, Michael; Schüttemeyer, Dirk; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

2015-04-01

Methane (CH4) is the second most important anthropogenic greenhouse gas beside carbon dioxide (CO2). Significant contributors to the global methane budget are fugitive emissions from landfills. Due to the growing world population, it is expected that the amount of waste and, therefore, waste disposal sites will increase in number and size in parts of the world, often adjacent growing megacities. Besides bottom-up modelling, a variety of ground based methods (e.g., flux chambers, trace gases, radial plume mapping, etc.) have been used to estimate (top-down) these fugitive emissions. Because landfills usually are large, sometimes with significant topographic relief, vary temporally, and leak/emit heterogeneously across their surface area, assessing total emission strength by ground-based techniques is often difficult. In this work, we show how airborne based remote sensing measurements of the column-averaged dry air mole fraction of CH4 can be utilized to estimate fugitive emissions from landfills in an urban environment by a mass balance approach. Subsequently, these emission rates are compared to airborne in-situ horizontal cross section measurements of CH4 taken within the planetary boundary layer (PBL) upwind and downwind of the landfill at different altitudes immediately after the remote sensing measurements were finished. Additional necessary parameters (e.g., wind direction, wind speed, aerosols, dew point temperature, etc.) for the data inversion are provided by a standard instrumentation suite for atmospheric measurements aboard the aircraft, and nearby ground-based weather stations. These measurements were part of the CO2 and Methane EXperiment (COMEX), which was executed during the summer 2014 in California and was co-funded by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The remote sensing measurements were taken by the Methane Airborne MAPper (MAMAP) developed and operated by the University of Bremen and

Climatic impacts of anthropogenic aerosols

Energy Technology Data Exchange (ETDEWEB)

Iversen, T. [Oslo Univ. (Norway)

1996-03-01

This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

Critical analysis in the inventories of methane in oil and gas industry; Analise critica de inventarios de metano na industria do oleo e gas

Energy Technology Data Exchange (ETDEWEB)

Schmall, Vicente; Montez, Edson [PETROBRAS, Sao Luiz, MA (Brazil). Seguranca, Meio Ambiente e Saude; Rosa, Ana Regina [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

The methane contribution arising from anthropogenic activities plays a role of great significance when elevating the concentration of gases of greenhouse effect found in the atmosphere. The methane presents a global warming potential twenty one times higher than the carbon dioxide and its atmospheric lifespan is lower than the other gases of greenhouse effect. Its control is regarded as being one of the most efficient ways to mitigate the global climate changes in the short term, which requires previous quantification of its emissions. PETROBRAS, aiming at achieving its environmental excellence, is implementing a system of management and inventory of gases emission into the atmosphere. The emissions inventory of 2003, published in its Social Sustainability Report appears as a result of this effort. This paper presents a comparison between the results generated by the PETROBRAS' Management and Inventory of Emissions System and those deriving from the application of the methodology suggested by the Intergovernmental Panel on Climate Change (IPCC). The impact of the chosen methodology, the aggregation level and the data availability of the emission sources on the results obtained are highlighted. (author)

Gridded anthropogenic emissions inventory and atmospheric transport of carbonyl sulfide in the U.S.: U.S. Anthropogenic COS Source and Transport

Energy Technology Data Exchange (ETDEWEB)

Zumkehr, Andrew [Sierra Nevada Research Institute, University of California, Merced California USA; Hilton, Timothy W. [Sierra Nevada Research Institute, University of California, Merced California USA; Whelan, Mary [Sierra Nevada Research Institute, University of California, Merced California USA; Smith, Steve [Joint Global Change Research Institute, PNNL, College Park Maryland USA; Campbell, J. Elliott [Sierra Nevada Research Institute, University of California, Merced California USA

2017-02-21

Carbonyl sulfide (COS or OCS), the most abundant sulfur containing gas in the troposphere, has recently emerged as a potentially important atmospheric tracer for the carbon cycle. Atmospheric inverse modeling studies may be able to use existing tower, airborne, and satellite observations of COS to infer information about photosynthesis. However, such analysis relies on gridded anthropogenic COS source estimates that are largely based on industry activity data from over three decades ago. Here we use updated emission factor data and industry activity data to develop a gridded inventory with a 0.1 degree resolution for the U.S. domain. The inventory includes the primary anthropogenic COS sources including direct emissions from the coal and aluminum industries as well as indirect sources from industrial carbon disulfide emissions. Compared to the previously published inventory, we found that the total anthropogenic source (direct and indirect) is 47% smaller. Using this new gridded inventory to drive the STEM/WRF atmospheric transport model, we found that the anthropogenic contribution to COS variation in the troposphere is small relative to the biosphere influence, which is encouraging of carbon cycle applications in this region. Additional anthropogenic sectors with highly uncertain emission factors require further field measurements.

Methane storage in porous activated carbons

NARCIS (Netherlands)

András Perl; prof. dr. Wim van Gemert

2014-01-01

Locally produced methane, - either as biomethane or power-to-gas product, has to be stored to provide a reliable gas source for the fluctuating demand of any local gas distribution network. Additionally, methane is a prominent transportation fuel but its suitability for vehicular application depends

Molecular dynamics study of methane hydrate formation at a water/methane interface.

Science.gov (United States)

Zhang, Junfang; Hawtin, R W; Yang, Ye; Nakagava, Edson; Rivero, M; Choi, S K; Rodger, P M

2008-08-28

We present molecular dynamics simulation results of a liquid water/methane interface, with and without an oligomer of poly(methylaminoethylmethacrylate), PMAEMA. PMAEMA is an active component of a commercial low dosage hydrate inhibitor (LDHI). Simulations were performed in the constant NPT ensemble at temperatures of 220, 235, 240, 245, and 250 K and a pressure of 300 bar. The simulations show the onset of methane hydrate growth within 30 ns for temperatures below 245 K in the methane/water systems; at 240 K there is an induction period of ca. 20 ns, but at lower temperatures growth commences immediately. The simulations were analyzed to calculate hydrate content, the propensity for hydrogen bond formation, and how these were affected by both temperature and the presence of the LDHI. As expected, both the hydrogen bond number and hydrate content decreased with increasing temperature, though little difference was observed between the lowest two temperatures considered. In the presence of PMAEMA, the temperature below which sustained hydrate growth occurred was observed to decrease. Some of the implications for the role of PMAEMA in LDHIs are discussed.

Methane storage in metal-organic frameworks.

Science.gov (United States)

He, Yabing; Zhou, Wei; Qian, Guodong; Chen, Banglin

2014-08-21

Natural gas (NG), whose main component is methane, is an attractive fuel for vehicular applications. Realization of safe, cheap and convenient means and materials for high-capacity methane storage can significantly facilitate the implementation of natural gas fuelled vehicles. The physisorption based process involving porous materials offers an efficient storage methodology and the emerging porous metal-organic frameworks have been explored as potential candidates because of their extraordinarily high porosities, tunable pore/cage sizes and easily immobilized functional sites. In this view, we provide an overview of the current status of metal-organic frameworks for methane storage.

Evidence for nitrite-dependent anaerobic methane oxidation as a previously overlooked microbial methane sink in wetlands

Science.gov (United States)

Hu, Bao-lan; Shen, Li-dong; Lian, Xu; Zhu, Qun; Liu, Shuai; Huang, Qian; He, Zhan-fei; Geng, Sha; Cheng, Dong-qing; Lou, Li-ping; Xu, Xiang-yang; Zheng, Ping; He, Yun-feng

2014-01-01

The process of nitrite-dependent anaerobic methane oxidation (n-damo) was recently discovered and shown to be mediated by “Candidatus Methylomirabilis oxyfera” (M. oxyfera). Here, evidence for n-damo in three different freshwater wetlands located in southeastern China was obtained using stable isotope measurements, quantitative PCR assays, and 16S rRNA and particulate methane monooxygenase gene clone library analyses. Stable isotope experiments confirmed the occurrence of n-damo in the examined wetlands, and the potential n-damo rates ranged from 0.31 to 5.43 nmol CO2 per gram of dry soil per day at different depths of soil cores. A combined analysis of 16S rRNA and particulate methane monooxygenase genes demonstrated that M. oxyfera-like bacteria were mainly present in the deep soil with a maximum abundance of 3.2 × 107 gene copies per gram of dry soil. It is estimated that ∼0.51 g of CH4 m−2 per year could be linked to the n-damo process in the examined wetlands based on the measured potential n-damo rates. This study presents previously unidentified confirmation that the n-damo process is a previously overlooked microbial methane sink in wetlands, and n-damo has the potential to be a globally important methane sink due to increasing nitrogen pollution. PMID:24616523

Building a better methane generation model: Validating models with methane recovery rates from 35 Canadian landfills.

Science.gov (United States)

Thompson, Shirley; Sawyer, Jennifer; Bonam, Rathan; Valdivia, J E

2009-07-01

The German EPER, TNO, Belgium, LandGEM, and Scholl Canyon models for estimating methane production were compared to methane recovery rates for 35 Canadian landfills, assuming that 20% of emissions were not recovered. Two different fractions of degradable organic carbon (DOC(f)) were applied in all models. Most models performed better when the DOC(f) was 0.5 compared to 0.77. The Belgium, Scholl Canyon, and LandGEM version 2.01 models produced the best results of the existing models with respective mean absolute errors compared to methane generation rates (recovery rates + 20%) of 91%, 71%, and 89% at 0.50 DOC(f) and 171%, 115%, and 81% at 0.77 DOC(f). The Scholl Canyon model typically overestimated methane recovery rates and the LandGEM version 2.01 model, which modifies the Scholl Canyon model by dividing waste by 10, consistently underestimated methane recovery rates; this comparison suggested that modifying the divisor for waste in the Scholl Canyon model between one and ten could improve its accuracy. At 0.50 DOC(f) and 0.77 DOC(f) the modified model had the lowest absolute mean error when divided by 1.5 yielding 63 +/- 45% and 2.3 yielding 57 +/- 47%, respectively. These modified models reduced error and variability substantially and both have a strong correlation of r = 0.92.

Direct Activation Of Methane

KAUST Repository

Basset, Jean-Marie

2013-07-15

Heteropolyacids (HPAs) can activate methane at ambient temperature (e.g., 20.degree. C.) and atmospheric pressure, and transform methane to acetic acid, in the absence of any noble metal such as Pd). The HPAs can be, for example, those with Keggin structure: H.sub.4SiW.sub.12O.sub.40, H.sub.3PW.sub.12O.sub.40, H.sub.4SiMo.sub.12O.sub.40, or H.sub.3PMo.sub.12O.sub.40, can be when supported on silica.

Working group report: methane emissions from coal mining

International Nuclear Information System (INIS)

Kruger, D.

1993-01-01

The process of coalification inherently generates methane and other byproducts. The amount of methane released during coal mining is a function of coal rank and depth, gas content, and mining methods, as well as other factors such as moisture. In most underground mines, methane is removed by drawing large quantities of air through the mine releasing the air into the atmosphere. In surface mines, exposed coal faces and surfaces, as well as areas of coal rubble created by blasting operations are believed to be the major sources of methane. A portion of the methane emitted from coal mining comes from post-mining activities such as coal processing, transportation, and utilisation. Some methane is also released from coal waste piles and abandoned mines. This paper highlights difficulties with previous methane emission studies namely: absence of data on which to base estimates; use of national data to develop global estimates; failure to include all possible emission sources; overreliance on statistical estimation methodologies. It recommends a 'tiered' approach for the estimation of emissions from underground mines, surface mines and post-mining activities. For each source, two or more approaches (or 'tiers') are presented, with the first tier requiring basic and readily available data and higher tiers requiring additional data. 29 refs., 3 tabs

On-line monitoring of methane in sewer air.

Science.gov (United States)

Liu, Yiwen; Sharma, Keshab R; Murthy, Sudhir; Johnson, Ian; Evans, Ted; Yuan, Zhiguo

2014-10-16

Methane is a highly potent greenhouse gas and contributes significantly to climate change. Recent studies have shown significant methane production in sewers. The studies conducted so far have relied on manual sampling followed by off-line laboratory-based chromatography analysis. These methods are labor-intensive when measuring methane emissions from a large number of sewers, and do not capture the dynamic variations in methane production. In this study, we investigated the suitability of infrared spectroscopy-based on-line methane sensors for measuring methane in humid and condensing sewer air. Two such sensors were comprehensively tested in the laboratory. Both sensors displayed high linearity (R(2) > 0.999), with a detection limit of 0.023% and 0.110% by volume, respectively. Both sensors were robust against ambient temperature variations in the range of 5 to 35°C. While one sensor was robust against humidity variations, the other was found to be significantly affected by humidity. However, the problem was solved by equipping the sensor with a heating unit to increase the sensor surface temperature to 35°C. Field studies at three sites confirmed the performance and accuracy of the sensors when applied to actual sewer conditions, and revealed substantial and highly dynamic methane concentrations in sewer air.

Marine methane cycle simulations for the period of early global warming

Energy Technology Data Exchange (ETDEWEB)

Elliott, S.; Maltrud, M.; Reagan, M.T.; Moridis, G.J.; Cameron-Smith, P.J.

2011-01-02

Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH{sub 4} distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

Marine methane cycle simulations for the period of early global warming

Science.gov (United States)

Elliott, Scott; Maltrud, Mathew; Reagan, Matthew; Moridis, George; Cameron-Smith, Philip

2011-03-01

Geochemical environments, fates, and effects are modeled for methane released into seawater by the decomposition of climate-sensitive clathrates. A contemporary global background cycle is first constructed, within the framework of the Parallel Ocean Program. Input from organics in the upper thermocline is related to oxygen levels, and microbial consumption is parameterized from available rate measurements. Seepage into bottom layers is then superimposed, representing typical seabed fluid flow. The resulting CH4 distribution is validated against surface saturation ratios, vertical sections, and slope plume studies. Injections of clathrate-derived methane are explored by distributing a small number of point sources around the Arctic continental shelf, where stocks are extensive and susceptible to instability during the first few decades of global warming. Isolated bottom cells are assigned dissolved gas fluxes from porous-media simulation. Given the present bulk removal pattern, methane does not penetrate far from emission sites. Accumulated effects, however, spread to the regional scale following the modeled current system. Both hypoxification and acidification are documented. Sensitivity studies illustrate a potential for material restrictions to broaden the perturbations, since methanotrophic consumers require nutrients and trace metals. When such factors are considered, methane buildup within the Arctic basin is enhanced. However, freshened polar surface waters act as a barrier to atmospheric transfer, diverting products into the deep return flow. Uncertainties in the logic and calculations are enumerated including those inherent in high-latitude clathrate abundance, buoyant effluent rise through the column, representation of the general circulation, and bacterial growth kinetics.

Technical Note: Methionine, a precursor of methane in living plants

Science.gov (United States)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2015-03-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention.

Science.gov (United States)

Kroeger, Kevin D; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

2017-09-20

Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as "Blue Carbon"), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH 4 ) and CO 2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH 4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

Restoring tides to reduce methane emissions in impounded wetlands: A new and potent Blue Carbon climate change intervention

Science.gov (United States)

Kroeger, Kevin D.; Crooks, Stephen; Moseman-Valtierra, Serena; Tang, Jianwu

2017-01-01

Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as “Blue Carbon”), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH4) and CO2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.

Global climate: Methane contribution to greenhouse effect

International Nuclear Information System (INIS)

Metalli, P.

1992-01-01

The global atmospheric concentration of methane greatly contributes to the severity of the greenhouse effect. It has been estimated that this concentration, due mainly to human activities, is growing at the rate of roughly 1.1% per year. Environmental scientists suggest that a reduction, even as small as 10%, in global methane emissions would be enough to curtail the hypothetical global warning scenarios forecasted for the up-coming century. Through the recovery of methane from municipal and farm wastes, as well as, through the control of methane leaks and dispersions in coal mining and petrochemical processes, substantial progress towards the abatement of greenhouse gas effects could be achieved without having to resort to economically detrimental limitations on the use of fossil fuels

Methane leakage in natural gas operations

International Nuclear Information System (INIS)

Jennervik, A.

1992-01-01

The world gas industry is efficient in conservation of natural gas within its systems. As the influence of methane as an infra-red absorbent gas has been more widely recognized, the considerations of methane's greenhouse effect has become vitally important to gas companies around the world. The industry is universally environmentally conscious. natural gas transmission and distribution companies want to maintain their image as suppliers of clean fuel. Further reductions in methane leakage --- particularly in older distribution systems --- can, should and will be pursued. Unfortunately, there has been little exchange of views on methane leakages between commentators on environmental matters and gas companies and organizations. There is absolutely no need for the industry to avoid the issue of greenhouse gases. Without industry involvement, the environmental debate concerning fossil fuels could lead to selective interpretation of scientific views and available evidence. Companies and authorities would be presented with confusing, contradictory evidence on which to base policy approaches and regulations

Multiparametric methane sensor for environmental monitoring

Science.gov (United States)

Borecki, M.; Duk, M.; Kociubiński, A.; Korwin-Pawlowski, M. L.

2016-12-01

Today, methane sensors find applications mostly in safety alarm installations, gas parameters detection and air pollution classification. Such sensors and sensors elements exists for industry and home use. Under development area of methane sensors application is dedicated to ground gases monitoring. Proper monitoring of soil gases requires reliable and maintenance-free semi-constant and longtime examination at relatively low cost of equipment. The sensors for soil monitoring have to work on soil probe. Therefore, sensor is exposed to environment conditions, as a wide range of temperatures and a full scale of humidity changes, as well as rain, snow and wind, that are not specified for classical methane sensors. Development of such sensor is presented in this paper. The presented sensor construction consists of five commercial non dispersive infra-red (NDIR) methane sensing units, a set of temperature and humidity sensing units, a gas chamber equipped with a micro-fan, automated gas valves and also a microcontroller that controls the measuring procedure. The electronics part of sensor was installed into customized 3D printed housing equipped with self-developed gas valves. The main development of proposed sensor is on the side of experimental evaluation of construction reliability and results of data processing included safety procedures and function for hardware error correction. Redundant methane sensor units are used providing measurement error correction as well as improved measurement accuracy. The humidity and temperature sensors are used for internal compensation of methane measurements as well as for cutting-off the sensor from the environment when the conditions exceed allowable parameters. Results obtained during environment sensing prove that the gas concentration readings are not sensitive to gas chamber vertical or horizontal position. It is important as vertical sensor installation on soil probe is simpler that horizontal one. Data acquired during six

IPNS grooved, solid methane moderator

International Nuclear Information System (INIS)

Carpenter, J.M.; Schulke, A.W.; Scott, T.L.; Wozniak, D.G.; Benson, B.E.; Leyda, B.D.

1985-01-01

There are two motives for using cold moderators in pulsed neutron sources, to provide higher fluxes of long-wavelength neutrons, and to extend the epithermal range with its short pulse structure to lower energies. For both these purposes solid methane, operated at the lowest possible temperatures, is the best material we know of. Two problems accompany the use of solid methane in high power sources, namely heat transport in view of the low thermal conductivity of solid methane, and deterioration due to radiation damage. We have designed a system suitable to operate in IPNS, subject to nuclear heating of about 25 W, which incorporates an aluminum foam matrix to conduct the heat from within the moderator. We report the results of the first few months' operation and of a few tests that we have performed

Separating natural acidity from anthropogenic acidification in the spring flood of northern Sweden

International Nuclear Information System (INIS)

Laudon, Hjalmar

2000-01-01

Spring flood is an occasion for transient hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also very susceptible to anthropogenic acidification. Belief that acid deposition is primarily responsible for pH decline during spring flood has been an important factor in the decision to spend close to one billion Swedish crowns to lime surface waters in northern Sweden during the last decade. The objective of this work is to present an operational tool, the Boreal Dilution Model (BDM), for separating and quantifying the anthropogenic and natural contributions to episodic acidification during spring flood episodes in northern Sweden. The limited data requirements of 10-15 stream water samples before and during spring flood make the BDM suitable for widespread use in environmental monitoring programs. This creates a possibility for distinguishing trends and spatial patterns in the human impact as well as natural pH decline. The results from applying the BDM, and a one point 'pBDM' version of the model, in northern Sweden demonstrate that the anthropogenic component associated with spring flood episodes is now generally limited. Instead it is the combination of natural organic acidity and dilution of the buffering capacity that is the major driving mechanism of episodic acidity during spring flood events in the region. While the anthropogenic component of episodic acidification generally contributes 0.1 to 0.3 pH units to the natural pH decline of up to 2.5 pH units, the current regional extent of areas that are severely affected by anthropogenically driven episodes is approximately 6%. Prior to the initiation of the Swedish Environmental Protection Agency's 'Episode Project' the limited spring flood data together with lack of a systematic methodology for determining liming candidates forced the liming authorities to base the remediation strategy in northern Sweden on biological indications. But, since there are more

Energy sector methane recovery and use: the importance of policy

Energy Technology Data Exchange (ETDEWEB)

Tom Kerr; Michelle Hershman

2009-08-15

To raise awareness about appropriate policy options to advance methane recovery and use in the energy sector, the IEA has conducted a series of analyses and studies over the past few years. This report continues IEA efforts by providing policy makers with examples and best practices in methane mitigation policy design and implementation. This report offers an overview of four types of methane mitigation projects that have the strongest links to the energy sector: oil and gas methane recovery and reduction of leaks and losses; coal mine methane; landfill methane; and manure methane recovery and use. It identifies successful policies that have been used to advance these important projects. This information is intended to guide policy makers as they search for low-cost, near-term solutions to climate change. 38 refs., 10 figs., 1 app.

30 CFR 75.1106-1 - Test for methane.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test for methane. 75.1106-1 Section 75.1106-1... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-1 Test for methane. Until December 31, 1970, a permissible flame safety lamp may be used to make tests for methane required by the...

The role of anthropogenic aerosol emission reduction in achieving the Paris Agreement's objective

Science.gov (United States)

Hienola, Anca; Pietikäinen, Joni-Pekka; O'Donnell, Declan; Partanen, Antti-Ilari; Korhonen, Hannele; Laaksonen, Ari

2017-04-01

The Paris agreement reached in December 2015 under the auspices of the United Nation Framework Convention on Climate Change (UNFCCC) aims at holding the global temperature increase to well below 2◦C above preindustrial levels and "to pursue efforts to limit the temperature increase to 1.5◦C above preindustrial levels". Limiting warming to any level implies that the total amount of carbon dioxide (CO2) - the dominant driver of long-term temperatures - that can ever be emitted into the atmosphere is finite. Essentially, this means that global CO2 emissions need to become net zero. CO2 is not the only pollutant causing warming, although it is the most persistent. Short-lived, non-CO2 climate forcers also must also be considered. Whereas much effort has been put into defining a threshold for temperature increase and zero net carbon emissions, surprisingly little attention has been paid to the non-CO2 climate forcers, including not just the non-CO2 greenhouse gases (methane (CH4), nitrous oxide (N2O), halocarbons etc.) but also the anthropogenic aerosols like black carbon (BC), organic carbon (OC) and sulfate. This study investigates the possibility of limiting the temperature increase to 1.5◦C by the end of the century under different future scenarios of anthropogenic aerosol emissions simulated with the very simplistic MAGICC climate carbon cycle model as well as with ECHAM6.1-HAM2.2-SALSA + UVic ESCM. The simulations include two different CO2 scenarios- RCP3PD as control and a CO2 reduction leading to 1.5◦C (which translates into reaching the net zero CO2 emissions by mid 2040s followed by negative emissions by the end of the century); each CO2 scenario includes also two aerosol pollution control cases denoted with CLE (current legislation) and MFR (maximum feasible reduction). The main result of the above scenarios is that the stronger the anthropogenic aerosol emission reduction is, the more significant the temperature increase by 2100 relative to pre

Biogenic coal-to-methane conversion efficiency decreases after repeated organic amendment

Science.gov (United States)

Davis, Katherine J.; Barnhart, Elliott P.; Fields, Matthew W.; Gerlach, Robin

2018-01-01

Addition of organic amendments to coal-containing systems can increase the rate and extent of biogenic methane production for 60–80 days before production slows or stops. Understanding the effect of repeated amendment additions on the rate and extent of enhanced coal-dependent methane production is important if biological coal-to-methane conversion is to be enhanced on a commercial scale. Microalgal biomass was added at a concentration of 0.1 g/L to microcosms with and without coal on days 0, 76, and 117. Rates of methane production were enhanced after the initial amendment but coal-containing treatments produced successively decreasing amounts of methane with each amendment. During the first amendment period, 113% of carbon added as amendment was recovered as methane, whereas in the second and third amendment periods, 39% and 32% of carbon added as amendment was recovered as methane, respectively. Additionally, algae-amended coal treatments produced ∼38% more methane than unamended coal treatments and ∼180% more methane than amended coal-free treatments after one amendment. However, a second amendment addition resulted in only an ∼25% increase in methane production for coal versus noncoal treatments and a third amendment addition resulted in similar methane production in both coal and noncoal treatments. Successive amendment additions appeared to result in a shift from coal-to-methane conversion to amendment-to-methane conversion. The reported results indicate that a better understanding is needed of the potential impacts and efficiencies of repeated stimulation for enhanced coal-to-methane conversion.

Methane fluxes and inventories in the accretionary prism of southwestern Taiwan

Science.gov (United States)

Lin, L. H.; Chen, N. C.; Yang, T. F.; Hong, W. L.; Chen, H. W.; Chen, H. C.; Hu, C. Y.; Huang, Y. C.; Lin, S.; Su, C. C.; Liao, W. Z.; Sun, C. H.; Wang, P. L.; Yang, T.; Jiang, S. Y.; Liu, C. S.; Wang, Y.; Chung, S. H.

2017-12-01

Sediments distributed across marine and terrestrial realms represent the largest methane reservoir on Earth. The degassing of methane facilitated through either geological structures or perturbation would contribute significantly to global climatic fluctuation and elemental cycling. The exact fluxes and processes governing methane production, consumption and transport in a geological system remain largely unknown in part due to the limited coverage and access of samples. In this study, more than 200 sediment cores were collected from offshore and onshore southwestern Taiwan and analyzed for their gas and aqueous geochemistry. These data combined with published data and existing parameters of subduction system were used to calculate methane fluxes across different geochemical transitions and to develop scenarios of mass balance to constrain deep microbial and thermogenic methane production rates within the Taiwanese accretionary prism. The results showed that high methane fluxes tend to be associated with structural features, suggesting a strong structural control on methane transport. A significant portion of ascending methane (>50%) was consumed by anaerobic oxidation of methane at most sites. Gas compositions and isotopes revealed a transition from the predominance of microbial methane in the passive margin to thermogenic methane at the upper slope of the active margin and onshore mud volcanoes. Methane production and consumption at shallow depths were nearly offset with a small fraction of residual methane discharged into seawater or the atmosphere. The flux imbalance arose primarily from the deep microbial and thermogenic production and could be likely accounted for by the sequestration of methane into hydrate forms, and clay absorption.

Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years

Science.gov (United States)

Wooller, Matthew J.; Pohlman, John W.; Gaglioti, Benjamin V.; Langdon, Peter; Jones, Miriam; Anthony, Katey M. Walter; Becker, Kevin W.; Hinrichs, Kai-Uwe; Elvert, Marcus

2012-01-01

Atmospheric contributions of methane from Arctic wetlands during the Holocene are dynamic and linked to climate oscillations. However, long-term records linking climate variability to methane availability in Arctic wetlands are lacking. We present a multi-proxy ~12,000 year paleoecological reconstruction of intermittent methane availability from a radiocarbon-dated sediment core (LQ-West) taken from a shallow tundra lake (Qalluuraq Lake) in Arctic Alaska. Specifically, stable carbon isotopic values of photosynthetic biomarkers and methane are utilized to estimate the proportional contribution of methane-derived carbon to lake-sediment-preserved benthic (chironomids) and pelagic (cladocerans) components over the last ~12,000 years. These results were compared to temperature, hydrologic, and habitat reconstructions from the same site using chironomid assemblage data, oxygen isotopes of chironomid head capsules, and radiocarbon ages of plant macrofossils. Cladoceran ephippia from ~4,000 cal year BP sediments have δ13C values that range from ~−39 to −31‰, suggesting peak methane carbon assimilation at that time. These low δ13C values coincide with an apparent decrease in effective moisture and development of a wetland that included Sphagnum subsecundum. Incorporation of methane-derived carbon by chironomids and cladocerans decreased from ~2,500 to 1,500 cal year BP, coinciding with a temperature decrease. Live-collected chironomids with a radiocarbon age of 1,640 cal year BP, and fossil chironomids from 1,500 cal year BP in the core illustrate that ‘old’ carbon has also contributed to the development of the aquatic ecosystem since ~1,500 cal year BP. The relatively low δ13C values of aquatic invertebrates (as low as −40.5‰) provide evidence of methane incorporation by lake invertebrates, and suggest intermittent climate-linked methane release from the lake throughout the Holocene.

Interference-free mid-IR laser absorption detection of methane

International Nuclear Information System (INIS)

Pyun, Sung Hyun; Cho, Jungwan; Davidson, David F; Hanson, Ronald K

2011-01-01

A novel, mid-IR scanned-wavelength laser absorption diagnostic was developed for time-resolved, interference-free, absorption measurement of methane concentration. A differential absorption (peak minus valley) scheme was used that takes advantage of the structural differences of the absorption spectrum of methane and other hydrocarbons. A peak and valley wavelength pair was selected to maximize the differential cross-section (σ peak minus valley ) of methane for the maximum signal-to-noise ratio, and to minimize that of the interfering absorbers. Methane cross-sections at the peak and valley wavelengths were measured over a range of temperatures, 1000 to 2000 K, and pressures 1.3 to 5.4 atm. The cross-sections of the interfering absorbers were assumed constant over the small wavelength interval between the methane peak and valley features. Using this diagnostic, methane concentration time histories during n-heptane pyrolysis were measured behind reflected shock waves in a shock tube. The differential absorption scheme efficiently rejected the absorption interference and successfully recovered the vapor-phase methane concentration. These measurements allowed the comparison with methane concentration time-history simulations derived from a current n-heptane reaction mechanism (Sirjean et al 2009 A high-temperature chemical kinetic model of n-alkane oxidation JetSurF version 1.0)

Termites facilitate methane oxidation and shape the methanotrophic community.

Science.gov (United States)

Ho, Adrian; Erens, Hans; Mujinya, Basile Bazirake; Boeckx, Pascal; Baert, Geert; Schneider, Bellinda; Frenzel, Peter; Boon, Nico; Van Ranst, Eric

2013-12-01

Termite-derived methane contributes 3 to 4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of the methane produced can be consumed by methanotrophs that inhabit the mound material, yet the methanotroph ecology in these environments is virtually unknown. The potential for methane oxidation was determined using slurry incubations under conditions with high (12%) and in situ (∼0.004%) methane concentrations through a vertical profile of a termite (Macrotermes falciger) mound and a reference soil. Interestingly, the mound material showed higher methanotrophic activity. The methanotroph community structure was determined by means of a pmoA-based diagnostic microarray. Although the methanotrophs in the mound were derived from populations in the reference soil, it appears that termite activity selected for a distinct community. Applying an indicator species analysis revealed that putative atmospheric methane oxidizers (high-indicator-value probes specific for the JR3 cluster) were indicative of the active nest area, whereas methanotrophs belonging to both type I and type II were indicative of the reference soil. We conclude that termites modify their environment, resulting in higher methane oxidation and selecting and/or enriching for a distinct methanotroph population.

Development and governance of renewable methane use in transport

Energy Technology Data Exchange (ETDEWEB)

Lampinen, Ari

2013-10-15

Renewable methane is promoted in many countries as a sustainable alternative to fossil fuels in all types of transport applications. This article examines development, governance and motives for the use of biogas, synthetic biogas, wind methane and other types of renewable methane in transport. Fossil methane fuels, such as natural gas, shale gas and synthetic natural gas, are included as a comparison. Compressed town gas played an important role in the adoption of methane for traffic use, so its history is also examined. Three waves of development in the use of traffic biogas are identified: the Second World War, the 1970s oil crises, and the present day quest for sustainability. While biogas has been used in transport since the 1930s, the other renewable methane fuels are now emerging in the commercial market with only a few years of history. The article looks at the use of renewable methane in a global perspective, although most of the examples are from Europe, as the majority of the technological and political advances have been European.

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

Energy Technology Data Exchange (ETDEWEB)

Don Augenstein

1999-01-11

''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

Potential for biohydrogen and methane production from olive pulp

DEFF Research Database (Denmark)

Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær

2005-01-01

The present study investigates the potential for thermophilic biohydrogen and methane production from olive pulp, which is the semi-solid residue coming from the two-phase processing of olives. It focussed on: a) production of methane from the raw olive pulp, b) anaerobic bio-production of hydrogen...... from the olive pulp, and c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane. Both continuous and batch experiments were performed. The hydrogen potential of the olive pulp amounted to 1.6 mmole H-2 per g TS. The methane potential of the raw olive pulp...... and hydrogen-effluent was as high as 19 mmole CH4 per g TS. This suggests that olive pulp is an ideal substrate for methane production and it shows that biohydrogen production can be very efficiently coupled with a subsequent step for methane production....

Raman and FTIR spectroscopy of methane in olivine

Science.gov (United States)

Smith, A.; Oze, C.; Rossman, G. R.; Celestian, A. J.

2017-12-01

Olivine has been proposed to be a direct source of methane (CH4) in serpentinization systems and experiments. Here, Raman and Fourier Transform Infrared (FTIR) spectroscopy were used to verify the presence and abundance of CH4 in olivine samples from nine localities, including the San Carlos olivine. Raman analyses did not identify any methane in the olivine samples. As olivine is orthorhombic, three polarized FTIR spectra were obtained for the olivine samples. No methane was detected in any of the olivine samples using FTIR. Overall, olivine investigated in this study does not appear to be a primary source of methane.

GOSAT-2014 methane spectral line list

International Nuclear Information System (INIS)

Nikitin, A.V.; Lyulin, O.M.; Mikhailenko, S.N.; Perevalov, V.I.; Filippov, N.N.; Grigoriev, I.M.; Morino, I.; Yoshida, Y.; Matsunaga, T.

2015-01-01

The updated methane spectral line list GOSAT-2014 for the 5550–6240 cm −1 region with the intensity cutoff of 5×10 –25 cm/molecule at 296 K is presented. The line list is based on the extensive measurements of the methane spectral line parameters performed at different temperatures and pressures of methane without and with buffer gases N 2 , O 2 and air. It contains the following spectral line parameters of about 12150 transitions: line position, line intensity, energy of lower state, air-induced and self-pressure-induced broadening and shift coefficients and temperature exponent of air-broadening coefficient. The accuracy of the line positions and intensities are considerably improved in comparison with the previous version GOSAT-2009. The improvement of the line list is done mainly due to the involving to the line position and intensity retrieval of six new spectra recorded with short path way (8.75 cm). The air-broadening and air-shift coefficients for the J-manifolds of the 2ν 3 (F 2 ) band are refitted using the new more precise values of the line positions and intensities. The line assignment is considerably extended. The lower state J-value was assigned to 6397 lines representing 94.4% of integrated intensity of the considering wavenumber region. The complete assignment was done for 2750 lines. - Highlights: • The upgrade of the GOSAT methane line list in the 5550–6240 cm −1 region is done. • 12,146 experimental methane line positions and intensities are retrieved. • 6376 lower energy levels for methane lines are determined

Assessing dissolved methane patterns in central New York groundwater

Directory of Open Access Journals (Sweden)

Lauren E. McPhillips

2014-07-01

New hydrological insights for this region: There was no significant difference between methane concentrations in valleys versus upslope locations, in water wells less than or greater than 1 km from a conventional gas well, and across different geohydrologic units. Methane concentrations were significantly higher in groundwater dominated by sodium chloride or sodium bicarbonate compared with groundwater dominated by calcium bicarbonate, indicating bedrock interactions and lengthy residence times as controls. A multivariate regression model of dissolved methane using only three variables (sodium, hardness, and barium explained 77% of methane variability, further emphasizing the dominance of geochemistry and hydrogeology as controls on baseline methane patterns.

Methane emission by adult ostriches (Struthio camelus).

Science.gov (United States)

Frei, Samuel; Dittmann, Marie T; Reutlinger, Christoph; Ortmann, Sylvia; Hatt, Jean-Michel; Kreuzer, Michael; Clauss, Marcus

2015-02-01

Ostriches (Struthio camelus) are herbivorous birds with a digestive physiology that shares several similarities with that of herbivorous mammals. Previous reports, however, claimed a very low methane emission from ostriches, which would be clearly different from mammals. If this could be confirmed, ostrich meat would represent a very attractive alternative to ruminant-and generally mammalian-meat by representing a particularly low-emission agricultural form of production. We individually measured, by chamber respirometry, the amount of oxygen consumed as well as carbon dioxide and methane emitted from six adult ostriches (body mass 108.3±8.3 kg) during a 24-hour period when fed a pelleted lucerne diet. While oxygen consumption was in the range of values previously reported for ostriches, supporting the validity of our experimental setup, methane production was, at 17.5±3.2 L d(-1), much higher than previously reported for this species, and was of the magnitude expected for similar-sized, nonruminant mammalian herbivores. These results suggest that methane emission is similar between ostriches and nonruminant mammalian herbivores and that the environmental burden of these animals is comparable. The findings furthermore indicate that it appears justified to use currently available scaling equations for methane production of nonruminant mammals in paleo-reconstructions of methane production of herbivorous dinosaurs. Copyright © 2014. Published by Elsevier Inc.

Mars methane rises and falls with the seasons

Science.gov (United States)

Hand, Eric

2018-01-01

On Earth, atmospheric methane is a prominent sign of life. On Mars, the story is more complicated. Trace detections of methane, alongside glimpses of larger spikes, have fueled debates about biological and nonbiological sources of the gas. Now, NASA scientists have announced a new twist in the tale: Methane regularly rises to a peak in late northern summer in a seasonal pattern. The swings are larger than can be explained by the planet's seasonal freeze-thaw cycles. The wiggles are a mystery within a larger mystery: claims of methane spikes an order of magnitude or two higher than the background. Some scientists say meteor showers could be responsible, by depositing carbonaceous material in the atmosphere that reacts to form methane. A close encounter on 24 January with debris from a comet could provide a chance to test the hypothesis.

Assessment of Methane Emissions – Impact of Using Natural Gas Engines in Unconventional Resource Development

Energy Technology Data Exchange (ETDEWEB)

Nix, Andrew [West Virginia Univ., Morgantown, WV (United States); Johnson, Derek [West Virginia Univ., Morgantown, WV (United States); Heltzel, Robert [West Virginia Univ., Morgantown, WV (United States); Oliver, Dakota [West Virginia Univ., Morgantown, WV (United States)

2018-04-08

Researchers at the Center for Alternative Fuels, Engines, and Emissions (CAFEE) completed a multi-year program under DE-FE0013689 entitled, “Assessing Fugitive Methane Emissions Impact Using Natural Gas Engines in Unconventional Resource Development.” When drilling activity was high and industry sought to lower operating costs and reduce emissions they began investing in dual fuel and dedicated natural gas engines to power unconventional well equipment. From a review of literature we determined that the prime-movers (or major fuel consumers) of unconventional well development were the service trucks (trucking), horizontal drilling rig (drilling) engines, and hydraulic stimulation pump (fracturing) engines. Based on early findings from on-road studies we assessed that conversion of prime movers to operate on natural gas could contribute to methane emissions associated with unconventional wells. As such, we collected significant in-use activity data from service trucks and in-use activity, fuel consumption, and gaseous emissions data from drilling and fracturing engines. Our findings confirmed that conversion of the prime movers to operate as dual fuel or dedicated natural gas – created an additional source of methane emissions. While some gaseous emissions were decreased from implementation of these technologies – methane and CO2 equivalent emissions tended to increase, especially for non-road engines. The increases were highest for dual fuel engines due to methane slip from the exhaust and engine crankcase. Dedicated natural gas engines tended to have lower exhaust methane emissions but higher CO2 emissions due to lower efficiency. Therefore, investing in currently available natural gas technologies for prime movers will increase the greenhouse gas footprint of the unconventional well development industry.

Significance of dissolved methane in effluents of anaerobically ...

Science.gov (United States)

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

Development of methane conversion improvement method by recycling of residual methane for steam reforming as a part of R and D of HTGR-hydrogen production system

International Nuclear Information System (INIS)

Inagaki, Yoshiyuki; Haga, Katsuhiro; Aita, Hideki; Sekita, Kenji; Hino, Ryutaro; Koiso, Hiroshi.

1998-01-01

The purpose of the present study is to improve methane conversion for an HTGR-steam reforming system by recycling of residual methane. The residual methane in a product gas after steam reforming was recycled with a gas separator of polyimide membrane. Gas separation characteristics of the separator were investigated experimentally and numerically, and an experimental study on recycling system was carried out. The results showed that the recycling system improves apparent methane conversion, ratio of methane conversion to methane supply from a cylinder, from 20 to 32% compared with those without recycling. (author)

Methane Emissions from Bangladesh: Bridging the Gap Between Ground-based and Space-borne Estimates

Science.gov (United States)

Peters, C.; Bennartz, R.; Hornberger, G. M.

2015-12-01

Gaining an understanding of methane (CH4) emission sources and atmospheric dispersion is an essential part of climate change research. Large-scale and global studies often rely on satellite observations of column CH4 mixing ratio whereas high-spatial resolution estimates rely on ground-based measurements. Extrapolation of ground-based measurements on, for example, rice paddies to broad region scales is highly uncertain because of spatio-temporal variability. We explore the use of ground-based river stage measurements and independent satellite observations of flooded area along with satellite measurements of CH4 mixing ratio to estimate the extent of methane emissions. Bangladesh, which comprises most of the Ganges Brahmaputra Meghna (GBM) delta, is a region of particular interest for studying spatio-temporal variation of methane emissions due to (1) broadscale rice cultivation and (2) seasonal flooding and atmospheric convection during the monsoon. Bangladesh and its deltaic landscape exhibit a broad range of environmental, economic, and social circumstances that are relevant to many nations in South and Southeast Asia. We explore the seasonal enhancement of CH4 in Bangladesh using passive remote sensing spectrometer CH4 products from the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) and the Atmospheric Infrared Sounder (AIRS). The seasonal variation of CH4 is compared to independent estimates of seasonal flooding from water gauge stations and space-based passive microwave water-to-land fractions from the Tropical Rainfall Measuring Mission Microwave Imager (TRMM-TMI). Annual cycles in inundation (natural and anthropogenic) and atmospheric CH4 concentrations show highly correlated seasonal signals. NOAA's HYSPLIT model is used to determine atmospheric residence time of ground CH4 fluxes. Using the satellite observations, we can narrow the large uncertainty in extrapolation of ground-based CH4 emission estimates from rice paddies

METHOD FOR PRODUCING ISOTOPIC METHANES AND PARTIALLY HALOGENATED DERIVATIVES THEROF

Science.gov (United States)

Frazer, J.W.

1959-08-18

A method is given for producing isotopic methanes and/ or partially halogenated derivatives. Lithium hydride, deuteride, or tritide is reacted with a halogenated methane or with a halogenated methane in combination with free halogen. The process is conveniently carried out by passing a halogenated methane preferably at low pressures or in an admixture with an inert gas through a fixed bed of finely divided lithium hydride heated initially to temperatures of 100 to 200 deg C depending upon the halogenated methane used.

Improved provincial emission inventory and speciation profiles of anthropogenic non-methane volatile organic compounds: a case study for Jiangsu, China

Directory of Open Access Journals (Sweden)

Y. Zhao

2017-06-01

Full Text Available Non-methane volatile organic compounds (NMVOCs are the key precursors of ozone (O3 and secondary organic aerosol (SOA formation. Accurate estimation of their emissions plays a crucial role in air quality simulation and policy making. We developed a high-resolution anthropogenic NMVOC emission inventory for Jiangsu in eastern China from 2005 to 2014, based on detailed information of individual local sources and field measurements of source profiles of the chemical industry. A total of 56 NMVOCs samples were collected in nine chemical plants and were then analyzed with a gas chromatography – mass spectrometry system (GC-MS. Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Various manufacturing technologies and raw materials led to discrepancies in source profiles between our domestic field tests and foreign results for synthetic rubber and ethylene production. The provincial NMVOC emissions were calculated to increase from 1774 Gg in 2005 to 2507 Gg in 2014, and relatively large emission densities were found in cities along the Yangtze River with developed economies and industries. The estimates were larger than those from most other available inventories, due mainly to the complete inclusion of emission sources and to the elevated activity levels from plant-by-plant investigation in this work. Industrial processes and solvent use were the largest contributing sectors, and their emissions were estimated to increase, respectively, from 461 to 958 and from 38 to 966 Gg. Alkanes, aromatics and oxygenated VOCs (OVOCs were the most important species, accounting for 25.9–29.9, 20.8–23.2 and 18.2–21.0 % to annual total emissions, respectively. Quantified with a Monte Carlo simulation, the uncertainties of annual NMVOC emissions

Improved provincial emission inventory and speciation profiles of anthropogenic non-methane volatile organic compounds: a case study for Jiangsu, China

Science.gov (United States)

Zhao, Yu; Mao, Pan; Zhou, Yaduan; Yang, Yang; Zhang, Jie; Wang, Shekou; Dong, Yanping; Xie, Fangjian; Yu, Yiyong; Li, Wenqing

2017-06-01

Non-methane volatile organic compounds (NMVOCs) are the key precursors of ozone (O3) and secondary organic aerosol (SOA) formation. Accurate estimation of their emissions plays a crucial role in air quality simulation and policy making. We developed a high-resolution anthropogenic NMVOC emission inventory for Jiangsu in eastern China from 2005 to 2014, based on detailed information of individual local sources and field measurements of source profiles of the chemical industry. A total of 56 NMVOCs samples were collected in nine chemical plants and were then analyzed with a gas chromatography - mass spectrometry system (GC-MS). Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Various manufacturing technologies and raw materials led to discrepancies in source profiles between our domestic field tests and foreign results for synthetic rubber and ethylene production. The provincial NMVOC emissions were calculated to increase from 1774 Gg in 2005 to 2507 Gg in 2014, and relatively large emission densities were found in cities along the Yangtze River with developed economies and industries. The estimates were larger than those from most other available inventories, due mainly to the complete inclusion of emission sources and to the elevated activity levels from plant-by-plant investigation in this work. Industrial processes and solvent use were the largest contributing sectors, and their emissions were estimated to increase, respectively, from 461 to 958 and from 38 to 966 Gg. Alkanes, aromatics and oxygenated VOCs (OVOCs) were the most important species, accounting for 25.9-29.9, 20.8-23.2 and 18.2-21.0 % to annual total emissions, respectively. Quantified with a Monte Carlo simulation, the uncertainties of annual NMVOC emissions vary slightly through the years

Aquatic herbivores facilitate the emission of methane from wetlands

NARCIS (Netherlands)

Dingemans, B.J.J.; Bakker, E.S.; Bodelier, P.L.E.

2011-01-01

Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on

Methane Seepage on Mars: Where to Look and Why.

Science.gov (United States)

Oehler, Dorothy Z; Etiope, Giuseppe

2017-12-01

Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available. Key

Optimal scheduling for enhanced coal bed methane production through CO2 injection

International Nuclear Information System (INIS)

Huang, Yuping; Zheng, Qipeng P.; Fan, Neng; Aminian, Kashy

2014-01-01

Highlights: • A novel deterministic optimization model for CO 2 -ECBM production scheduling. • Maximize the total profit from both sales of natural gas and CO 2 credits trading in the carbon market. • A stochastic model incorporating uncertainties and dynamics of NG price and CO 2 credit. - Abstract: Enhanced coal bed methane production with CO 2 injection (CO 2 -ECBM) is an effective technology for accessing the natural gas embedded in the traditionally unmineable coal seams. The revenue via this production process is generated not only by the sales of coal bed methane, but also by trading CO 2 credits in the carbon market. As the technology of CO 2 -ECBM becomes mature, its commercialization opportunities are also springing up. This paper proposes applicable mathematical models for CO 2 -ECBM production and compares the impacts of their production schedules on the total profit. A novel basic deterministic model for CO 2 -ECBM production including the technical and chemical details is proposed and then a multistage stochastic programming model is formulated in order to address uncertainties of natural gas price and CO 2 credit. Both models are nonlinear programming problems, which are solved by commercial nonlinear programming software BARON via GAMS. Numerical experiments show the benefits (e.g., expected profit gain) of using stochastic models versus deterministic models

Methanization, new opportunities for territories. National technical day - 13 May 2014, Paris. Collection of interventions. The Methanization Autonomy Nitrogen energy plan

International Nuclear Information System (INIS)

Bastide, Guillaume; Guilet, Marie; Banville, Sandrine; Rocher, Franck; Brosset, Denis; Chapelat, Nicolas; Le Roy, Philippe; Leboucher, Anne; Boucher, Sophie; Bolduan, Rainer; Pislor, Emilie; Desbles, Matthieu; Garoche, David; Decoopman, Bertrand; Deshayes, Odile; Mazzenga, Anthony; Quaak, Mauritz; Berthelot, Corinne

2014-05-01

This publication contains proceedings of a conference on methanization projects and techniques, notably in rural areas (there were 140 rural installations in France in 2014 and 20 centralised ones). Contributions thus give an overview of the present development of this sector, and of its perspectives over the medium to long term. A first set of contributions addressed the performance of a panel of farm-based and centralised methanization installations with technical, energy, environmental, agronomic and social assessments for 8 units (lessons learned from installation follow-up, recommendations for operation optimisation of 2 units), and a profitability study performed on 21 installations (lessons learned, profitability evolution for 2 installations). The second set of contributions addressed development perspectives of the methanization sector over the medium to long term. Contributions addressed the following issues: how to mobilise and process bio-wastes from big producers, other possible sources (energetic crops, intermediate crops for energy purposes or CIVE or crop residues), the use of digestate to reduce the use of mineral fertilizers, and emerging energetic valorisations of biogas. A last part presents the Methanization Autonomy Nitrogen Energy Plan (the EMAA plan) which aims at managing and valorising nitrogen (notably from breeding effluents), at developing a French model of agricultural methanization. The stakes of methanization for energy transition are outlined, and the operation of a methanization installation is described

Carbon-13 isotopic abundance and concentration of atmospheric methane for background air in the Southern and Northern Hemispheres from 1978 to 1989

International Nuclear Information System (INIS)

Stevens, C.M.; Sepanski; Morris, L.J.

1995-03-01

Atmospheric methane (CH 4 ) may become an increasingly important contributor to global warming in future years. Its atmospheric concentration has risen, doubling over the past several hundred years, and additional methane is thought to have a much greater effect on climate, on a per molecule basis, than additional C0 2 at present day concentrations (Shine et al. 1990). The causes of the increase of atmospheric CH 4 have been difficult to ascertain because of a lack of quantitative knowledge of the fluxes (i.e., net emissions) from the numerous anthropogenic and natural sources. The goal of CH 4 isotopic studies is to provide a constraint (and so reduce the uncertainties) in estimating the relative fluxes from the various isotopically distinct sources, whose combined fluxes must result in the measured atmospheric isotopic composition, after the fractionating effect of the atmospheric removal process is considered. In addition, knowledge of the spatial and temporal changes in the isotopic composition of atmospheric CH 4 , along with estimates of the fluxes from some of the major sources, makes it possible to calculate growth rates for sources whose temporal emissions trends would be difficult to measure directly

Methane source identification in Boston, Massachusetts using isotopic and ethane measurements

Science.gov (United States)

Down, A.; Jackson, R. B.; Plata, D.; McKain, K.; Wofsy, S. C.; Rella, C.; Crosson, E.; Phillips, N. G.

2012-12-01

Methane has substantial greenhouse warming potential and is the principle component of natural gas. Fugitive natural gas emissions could be a significant source of methane to the atmosphere. However, the cumulative magnitude of natural gas leaks is not yet well constrained. We used a combination of point source measurements and ambient monitoring to characterize the methane sources in the Boston urban area. We developed distinct fingerprints for natural gas and multiple biogenic methane sources based on hydrocarbon concentration and isotopic composition. We combine these data with periodic measurements of atmospheric methane and ethane concentration to estimate the fractional contribution of natural gas and biogenic methane sources to the cumulative urban methane flux in Boston. These results are used to inform an inverse model of urban methane concentration and emissions.

Isotopic fingerprints of anthropogenic molybdenum in lake sediments.

Science.gov (United States)

Chappaz, Anthony; Lyons, Timothy W; Gordon, Gwyneth W; Anbar, Ariel D

2012-10-16

We measured the molybdenum isotope compositions (δ(98)Mo) of well-dated sediment cores from two lakes in eastern Canada in an effort to distinguish between natural and anthropogenic contributions to these freshwater aquatic systems. Previously, Chappaz et al. (1) ascribed pronounced 20th-century Mo concentration enrichments in these lakes to anthropogenic inputs. δ(98)Mo values in the deeper sediments (reflecting predominantly natural Mo sources) differ dramatically between the two lakes: -0.32 ± 0.17‰ for oxic Lake Tantare and +0.64 ± 0.09‰ for anoxic Lake Vose. Sediment layers previously identified as enriched in anthropogenic Mo, however, reveal significant δ(98)Mo shifts of ± 0.3‰, resulting in isotopically heavier values of +0.05 ± 0.18‰ in Lake Tantare and lighter values of +0.31 ± 0.03‰ in Lake Vose. We argue that anthropogenic Mo modifies the isotopic composition of the recent sediments, and we determine δ(98)Mo(anthropogenic) values of 0.1 ± 0.1‰ (Lake Vose) and 0.2 ± 0.2‰ (Lake Tantare). These calculated inputs are consistent with the δ(98)Mo of molybdenite (MoS(2)) likely delivered to the lakes via smelting of porphyry copper deposits (Lake Vose) or through combustion of coal and oil also containing Mo (Lake Tantare). Our results confirm the utility of Mo isotopes as a promising fingerprint of human impacts and perhaps the specific sources of contamination. Importantly, the magnitudes of the anthropogenic inputs are large enough, relative to the natural Mo cycles in each lake, to have an impact on the microbiological communities.

Market research on biogas valorizations and methanization. Final report

International Nuclear Information System (INIS)

2010-09-01

This market research aims at giving an overview of the existing methanization installations and of their dynamics in France, at assessing biogas production and use, at analyzing the methanization market, and at defining development perspectives for this sector by 2020. Based on a survey of methanization installations, on interviews with many actors of this sector, and on a seminar organized on this topic, this report presents and comments market data for biogas valorization and methanization in different sectors: household, agricultural, and industrial and waste water processing plants. It comments evolution trends by 2020 for these sectors, and the role that the emerging sector of centralized methanization could have in the years to come

Effect of hemicellulolytic enzymes on mesophilic methane fermentation

Energy Technology Data Exchange (ETDEWEB)

Oi, S; Matsui, Y; Iizuka, M; Yamamoto, T

1977-01-01

Mesophilic methane fermentation was examined using soybean seed coat, a waste from soybean processing for oil manufacture, with or without treatment with hemicellulolytic enzymes of Aspergillus niger, and the following results were obtained: (1) The methane fermentation bacteria acclimated to soybean seed coat medium were shown to consume monosaccharides and evolve methane in the following decreasing order: glucose, fructose, mannose > xylose, galactose, glucosamine, galacturonic acid > arabinose. The bacteria were also shown to form methane from a gas mixture of hydrogen and carbon dioxide. (2) In fermentation of soybean seed coat treated with the fungal enzyme, about 70% of the total sugar content as consumed in four weeks, and the gas evolution was about twice that without the fungal enzyme. The gas evolved was composed of 60% methane and 36% carbon dioxide. In general, vigorous evolution of hydrogen and carbon dioxide occurred at a very early stage of fermentation, and was followed by formation of methane. The maximum gas evolution of the enzyme-treated mash took place in 6 days while that of untreated mash occurred one week later. Chemical oxygen demand of the supernatant of the former mash was decreased by fermentation to 7.0% of the initial level.

Cometary origin of atmospheric methane variations on Mars unlikely

Science.gov (United States)

Roos-Serote, M.; Atreya, S. K.; Webster, C. R.; Mahaffy, P. R.

2016-10-01

The detection of methane in the atmosphere of Mars was first reported in 2004. Since then a number of independent observations of methane have been reported, all showing temporal variability. Up until recently, the origin of methane was attributed to sources either indigenous to Mars or exogenous, where methane is a UV degradation byproduct of organics falling on to the surface. Most recently, a new hypothesis has been proposed that argues that the appearance and variation of methane are correlated with specific meteor events at Mars. Indeed, extraplanetary material can be brought to a planet when it passes through a meteoroid stream left behind by cometary bodies orbiting the Sun. This occurs repeatedly at specific times in a planet's year as streams tend to be fairly stable in space. In this paper, we revisit this latest hypothesis by carrying out a complete analysis of all available data on Mars atmospheric methane, including the very recent data not previously published, together with all published predicted meteor events for Mars. Whether we consider the collection of individual data points and predicted meteor events, whether we apply statistical analysis, or whether we consider different time spans between high methane measurements and the occurrence of meteor events, we find no compelling evidence for any correlation between atmospheric methane and predicted meteor events.

Anthropogenic effect on avalanche and debris flow activity

Directory of Open Access Journals (Sweden)

S. A. Sokratov

2013-01-01

Full Text Available The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoidable changes of the natural environment as the result of a construction and of use of the constructed infrastructure to be account for in corresponding planning of the protection measures.

Methane gas from cow dung

Energy Technology Data Exchange (ETDEWEB)

1974-01-01

The Khadi and Village Industries Commission offers a gobar gas (methane gas) production scheme. The gas plant, available in sizes of 60 to 3000 cu ft, requires only low maintenance expenditures. The cow dung, which is at present being wasted or burned as domestic fuel, can be used for manufacturing methane for fuel gas. The residue will be a good fertilizer for increasing food production. There are now about 4000 gobar gas plants in India.

Rapid Sediment Accumulation Results in High Methane Effluxes from Coastal Sediments.

Directory of Open Access Journals (Sweden)

Matthias Egger

Full Text Available Globally, the methane (CH4 efflux from the ocean to the atmosphere is small, despite high rates of CH4 production in continental shelf and slope environments. This low efflux results from the biological removal of CH4 through anaerobic oxidation with sulfate in marine sediments. In some settings, however, pore water CH4 is found throughout the sulfate-bearing zone, indicating an apparently inefficient oxidation barrier for CH4. Here we demonstrate that rapid sediment accumulation can explain this limited capacity for CH4 removal in coastal sediments. In a saline coastal reservoir (Lake Grevelingen, The Netherlands, we observed high diffusive CH4 effluxes from the sediment into the overlying water column (0.2-0.8 mol m-2 yr-1 during multiple years. Linear pore water CH4 profiles and the absence of an isotopic enrichment commonly associated with CH4 oxidation in a zone with high rates of sulfate reduction (50-170 nmol cm-3 d-1 both suggest that CH4 is bypassing the zone of sulfate reduction. We propose that the rapid sediment accumulation at this site (~ 13 cm yr-1 reduces the residence time of the CH4 oxidizing microorganisms in the sulfate/methane transition zone (< 5 years, thus making it difficult for these slow growing methanotrophic communities to build-up sufficient biomass to efficiently remove pore water CH4. In addition, our results indicate that the high input of organic matter (~ 91 mol C m-2 yr-1 allows for the co-occurrence of different dissimilatory respiration processes, such as (acetotrophic methanogenesis and sulfate reduction in the surface sediments by providing abundant substrate. We conclude that anthropogenic eutrophication and rapid sediment accumulation likely increase the release of CH4 from coastal sediments.

A Possible Sink for Methane on Mars

NARCIS (Netherlands)

Nørnberg, P.; Jensen, S. J. K.; Skibsted, J.; Jakobsen, H. J.; ten Kate, I. L.; Gunnlaugsson, H. P.; Merrison, J. P.; Finster, K.; Bak, E.; Iversen, J. J.; Kondrup, J. C.

2014-01-01

Mechanical simulated wind activation of mineral surfaces act as a trap for Methane through formation of covalent Si-C bonds stable up to temperatures above 250 C. This mechanism is proposed as a Methane sink on Mars.

Methane layering in bord and pillar workings.

CSIR Research Space (South Africa)

Creedy, DP

1997-08-01

Full Text Available This report reviews the state of knowledge on the occurrence, investigation, detection, monitoring, prevention and dispensation of methane layers in coal mines. Mining practice throughout the world in respect of methane layering is generally reliant...

14C measurements in aquifers with methane

International Nuclear Information System (INIS)

Barker, J.F.; Fritz, P.; Brown, R.M.

1978-01-01

A survey of various groundwater systems indicates that methane is a common trace constituent and occasionally a major carbon species in groundwaters. Thermocatalytic methane had delta 13 CCH 4 > -45% 0 and microbially-produced or biogenic methane had delta 13 CCH 4 0 . Groundwaters containing significant biogenic methane had abnormally heavy delta 13 C values for the inorganic carbon. Thermocatalytic methane had no apparent effect on the inorganic carbon. Because methanogenesis seriously affects the carbon isotope geochemistry of groundwaters, the correction of raw 14 C ages of affected groundwaters must consider these effects. Conceptual models are developed which adjust the 14 C activity of the groundwater for the effects of methanogenesis and for the dilution of carbon present during infiltration by simple dissolution of rock carbonate. These preliminary models are applied to groundwaters from the Alliston sand aquifer where methanogenesis has affected most samples. In this system, methanogenic bacteria using organic matter present in the aquifer matrix as substrate, have added inorganic carbon to the groundwater which has initiated further carbonate rock dissolution. These processes have diluted the inorganic carbon 14 C activity. (orig.) [de

Methane oxidation and degradation of organic compounds in landfill soil covers

DEFF Research Database (Denmark)

Scheutz, Charlotte; Kjeldsen, Peter

2002-01-01

High rates of methane oxidation and degradation of the lowed halogenated methanes (TCM and DCM) and HCFCs (HCFC-21 and HCFC-22) were found in an investigation of the oxidation of methane and halogenated organic compunds (HOCs) in landfill gas affected soil. The degradation followed zero-order kin......High rates of methane oxidation and degradation of the lowed halogenated methanes (TCM and DCM) and HCFCs (HCFC-21 and HCFC-22) were found in an investigation of the oxidation of methane and halogenated organic compunds (HOCs) in landfill gas affected soil. The degradation followed zero...

Biological conversion of coal gas to methane

Energy Technology Data Exchange (ETDEWEB)

Barik, S; Vega, J L; Clausen, E C; Gaddy, J L

1988-08-01

Biological conversion of low-Btu coal synthesis gas to higher Btu methane was demonstrated using both pure co-cultures and/or adapted-mixed anaerobic bacteria. Peptostreptococcus productus metabolized coal gas to mainly acetate and CO/sub 2/. The co-cultures containing methanogens converted these products to methane. In mixed culture studies, CH/sub 4/ and small amounts of acetate were produced. Reactor studies using stirred-tank and immobilized cell reactors exhibited excellent potential to convert CO, CO/sub 2/ and H/sub 2/ to methane at higher gas flow rates. Gas retention times ranging from 0.7 to 2 hours and high agitation were required for 90 percent CO conversion in these systems. This paper also illustrates the potential of biological methanation and demonstrates the need for good mass transfer in converting gas phase substrates. 21 refs., 1 fig., 7 tabs.

OXIDATIVE-REFORMING OF METHANE AND PARTIAL OXIDATION OF METHANE REACTIONS OVER NiO/PrO2/ZrO2 CATALYSTS: EFFECT OF NICKEL CONTENT

Directory of Open Access Journals (Sweden)

Y. J. O. Asencios

Full Text Available Abstract In this work the behavior of NiO-PrO2-ZrO2 catalysts containing various nickel loadings was evaluated in the partial oxidation of methane and oxidative-reforming reactions of methane. The catalysts were characterized by X-Ray Diffraction Analysis (in situ-XRD, Temperature Programmed Reduction (H2-TPR, Scanning Electron Microscopy (SEM/EDX and Adsorption-Desorption of nitrogen (BET area. The reactions were carried out at 750 °C and 1 atm for 5 hours. The catalysts were studied with different nickel content: 0, 5, 10 and 15% (related to total weight of catalyst, wt%. In both reactions, the catalyst containing the mixture of the three oxides (NiO/PrO2/ZrO2 with 15% nickel (15NiPrZr catalyst showed the best activity for the conversion of the reactants into Syngas and showed high selectivity for H2 and CO. The results suggest that the promoter PrO2 and the Niº centers are in a good proportion in the catalyst with 15% Ni. Our results showed that low nickel concentrations in the catalyst led to high metallic dispersion; however, very low nickel concentrations did not favor the methane transformation into Syngas. The catalyst containing only NiO/ZrO2 in the mixture was not sufficient for the catalysis. The presence of the promoter PrO2 was very important for the catalysis of the POM.