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methane conversion in the presence of oxygen under low-temperature radio frequency plasma

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Journal of Natural Gas Chemistry 2010年第6期19卷 605-610页

作者： Jinhai Yuan Xuejun Zhong Shiyu Tan College of Chemistry and Chemical Engineering Chongqing University of Science ＆ Technology Chongqing 401331 China Chongqing Chemical Engineering Design and Research Institute Chongqing 400039 China College of Chemistry and Chemical Engineering Chongqing University Chongqing 40004 China

methane conversion in the presence of oxygen under low-temperature radio frequency （RF） plasma was investigated.The experiment results indicated that the following four factors,i.e.,discharge voltage,discharge area,O2/CH4 molar ratio and total gas flowrate,affected remarkably the reaction performance.The optimum reaction conditions of methane conversion in the presence of O2 under RF plasma are as follows：discharge voltage 1050 V,discharge area 989.1mm 2,O2/CH4 molar ratio 1/10 and total gas flowrate 200 ml/min.A methane conversion of 91% could be reached under the optimum conditions.Oxygen is good for the breaking of C-H bonds and also acts as a sort of thinner.According to the low-temperature plasma characteristics,the macroscopic kinetics model of methane conversion in the presence of O2 under radio frequency plasma was studied.

关键词： methane oxygen radio frequency plasma C2 hydrocarbons kinetics

Construction of high-pressure adsorption isotherm:A tool for predicting coalbed methane recovery from Jharia coalfield,India

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International Journal of Mining Science and Technology 2019年第5期29卷 765-769页

作者： Mohammad Asif D.C.Panigrahi Paul Naveen Keka Ojha Department of Mining Engineering Indian Institute of Technology(ISM)Dhanbad 826004India Department of Petroleum Engineering Indian Institute of Technology(ISM)Dhanbad 826004India

Adsorption isotherm relates the gas storage capacity as a function of pressure at constant temperature.In this paper,adsorption isotherm of two dry borehole samples was constructed in the laboratory using the manometric method.Isotherm was measured for two gases,i.e.,CH4 and CO2 to pressure up to 8.4 MPa.Before the construction of sorption isotherm,coal was characterized by proximate,ultimate and petrographic analysis.Coalbed gas content of these two samples was found 2.29 m3/t and 2.75 m3/t.SEM images were obtained for the pore size distribution of coal using pore image analysis.Prediction of coalbed methane recovery from CH4 adsorption isotherm showed that these coalbeds are under saturated.CO2 isotherm was constructed to estimate enhanced coalbed methane(ECBM)recovery.Volume wise CO2/CH4 sorption ratio was found 2.09 times to 2.75 times respectively.This paper presents the interpretation of isotherm data to find the recovery factor of methane production from Jharia coalfield.

关键词： Coalbed methane Adsorption isotherm Pore image analysis Gas content Jharia coalfield

The Nord Stream pipeline gas leaks released approximately 220,000 tonnes of methane into the atmosphere

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Environmental Science and Ecotechnology 2022年第4期12卷 3-7页

作者： Mengwei Jia Fei Li Yuzhong Zhang Mousong Wu Yingsong Li Shuzhuang Feng Hengmao Wang Huilin Chen Weimin Ju Jun Lin Jianwei Cai Yongguang Zhang Fei Jiang Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology International Institute for Earth System ScienceNanjing UniversityNanjingJiangsu Province210023China Key Laboratory of Coastal Environment and Resources of Zhejiang Province School of EngineeringWestlake UniversityHangzhouZhejiang Province310030China Joint International Research Laboratory of Atmospheric and Earth System Sciences School of Atmospheric SciencesNanjing UniversityNanjingJiangsu Province210023China China Centre for Resources Satellite Data and Application Beijing100094China International Joint Carbon Neutrality Laboratory NanjingJiangsu Province210023China Nantong Academy of Intelligent Sensing NantongJiangsu Province226000China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application NanjingJiangsu Province210023China Frontiers Science Center for Critical Earth Material Cycling Nanjing UniversityNanjingJiangsu Province210023China

Sudden mega natural gas leaks of two Nord Stream pipelines in the Baltic Sea(Denmark)occurred from late September to early October 2022,releasing large amounts of methane into the atmosphere.We inferred the methane emissions of this event based on surface in situ observations using two inversion methods and two meteorological reanalysis datasets,supplemented with satellite-based observations.We conclude that approximately 220±30 Gg of methane was released from September 26 to October 1,2022.

关键词： methane approximate conclude

Variation characteristics of atmospheric methane and carbon dioxide in summertime at a coastal site in the South China Sea

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Frontiers of Environmental Science & Engineering 2022年第11期16卷 165-175页

作者： Yangyan Cheng Ye Shan Yuhuan Xue Yujiao Zhu Xinfeng Wang Likun Xue Yanguang Liu Fangli Qiao Min Zhang Key Laboratory of Marine Sciences and Numerical Modeling First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Environment Research Institute Shandong UniversityQingdao 266237China Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Shandong Key Laboratory of Marine Sciences and Numerical Modeling Qingdao 266061China

methane(CH_(4))and carbon dioxide(CO_(2))are the two most important greenhouse gases(GHGs).To examine the variation characteristics of CH_(4)and CO_(2)in the coastal South China Sea,atmospheric CH_(4)and CO_(2)measurements were performed in Bohe(BH),Guangdong,China,in summer 2021.By using an adaptive data analysis method,the diurnal patterns of CH_(4)and CO_(2)were clearly extracted and analysed in relation to the sea breeze(SB)and land breeze(LB),respectively.The average concentrations of CH_(4)and CO_(2)were 1876.91±31.13 ppb and 407.99±4.24 ppm during SB,and 1988.12±109.92 ppb and 421.54±14.89 ppm during LB,respectively.The values of CH_(4)and CO_(2)during SB basically coincided with the values and trends of marine background sites,showing that the BH station could serve as an ideal site for background GHG monitoring and dynamic analysis.The extracted diurnal variations in CH_(4)and CO_(2)showed sunrise high and sunset low patterns(with peaks at 5:00–7:00)during LB but mid-morning high and evening low patterns(with peaks at 9:00)during SB.The diurnal amplitude changes in both CH_(4)and CO_(2)during LB were almost two to three times those during SB.Wind direction significantly modulated the diurnal variations in CH_(4)and CO_(2).The results in this study provide a new way to examine the variations in GHGs on different timescales and can also help us gain a better understanding of GHG sources and distributions in the South China Sea.

关键词： methane Carbon dioxide Diurnal pattern Ensemble empirical mode decomposition South China Sea Sea breeze

Comparative methane estimation from cattle based on total CO_2 production using different techniques

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Animal Nutrition 2017年第2期3卷 175-179页

作者： Md N.Haque Hanne H.Hansen Ida M.L.D.Storm Jφrgen Madsen Department of Large Animal Sciences Faculty of Health and Medical SciencesUniversity of Copenhagen

The objective of this study was to compare the precision of CH4 estimates using calculated CO_2(HP) by the CO_2 method(CO_2 T) and measured CO_2 in the respiration chamber(CO_2 R). The CO_2 R and CO_2 T study was conducted as a 3 × 3 Latin square design where 3 Dexter heifers were allocated to metabolic cages for 3 periods. Each period consisted of 2 weeks of adaptation followed by 1 week of measurement with the CO_2 R and CO_2 T. The average body weight of the heifer was 226 ± 11 kg(means±SD). They were fed a total mixed ration, twice daily, with 1 of 3 supplements: wheat(W), molasses(M), or molasses mixed with sodium bicarbonate(Mbic). The dry mater intake(DMI: kg/day) was significantly greater(P < 0.001)in the metabolic cage compared with that in the respiration chamber. The daily CH4(L/day) emission was strongly correlated(r=0.78) between CO_2 T and CO_2 R. The daily CH4(L/kg DMI) emission by the CO_2 T was in the same magnitude as by the CO_2 R. The measured CO_2(L/day) production in the respiration chamber was not different(P = 0.39) from the calculated CO_2 production using the CO_2 T. This result concludes a reasonable accuracy and precision of CH4 estimation by the CO_2 T compared with the CO_2 R.

关键词： Carbon dioxide Precision methane Measurement Respiration chamber

A simple method for solving unidirectional methane gas flow in coal seam based on similarity solution

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International Journal of Mining Science and Technology 2018年第2期28卷 331-334页

作者： Zhou Yan Meng Qian Lin Baiquan Qin Jilong Zhou Guiping Key Laboratory of Gas and Fire Control for Coal Mines (China University of Mining & Technology) Ministry of Education School of Computer Science and Technology Jiangsu Normal University

The equation used to model the unidirectional flow of methane gas in coal seams is usually formulated as a nonlinear partial differential equation, which needs to be solved numerically with a computer program.Nevertheless, for people without access to the computer program, the conventional numerical method may be inconvenient. Thus, the objective here is to seek some method simpler than the conventional one for solving the flow problem. A commonly used model of the unidirectional methane gas flow is considered, where the methane adsorption is described by the Langmuir isotherm and the free gas is treated as real gas. By introducing the similarity solution, a simple method for solving the flow model is proposed, which can be done on a hand calculator. It is shown by two examples that the gas pressure profile obtained by the proposed method agrees well with the direct numerical solution of the flow model.

关键词： Coalbed methane Migration Unidirectional flow Similarity solution Simplified solving Numerical method

methane adsorption behavior on coal having different pore structures

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International Journal of Mining Science and Technology 2012年第6期22卷 756-760页

作者： Zhao Yi Jiang Chengfa Chu Wei Department of Chemical Engineering Sichuan University

The adsorption of methane onto five dry coal samples was measured at 298 K over the pressure range from 0 to 3.5 MPa using a volumetric method.The isotherm data were fitted to the Langmuir and the Freundlich equations.The kinetic data were fitted to a pseudo second order equation,the linear driving force equation(LDF),and an intra-particle diffusion model.These results showed that higher methane adsorption is correlated with larger micro-pore volumes and specific surface areas.The adsorption was related to the narrow micro-pore size distribution when the previous two parameters are large.The kinetics study showed that the kinetics of methane adsorption onto these five dry coal samples followed a pseudo second order model very well.methane adsorption rates are controlled by intra-particle diffusion.The faster the intra-particle diffusion,the faster the methane adsorption rate will be.

关键词： Pore structure methane adsorption Adsorption kinetics Model fitting

methane sensor based on palladium/MWNT nanocomposites

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Chinese Chemical Letters 2009年第5期20卷 608-610页

作者： Zhong Ping Li Yong Guo Suo Zhu Wu Shao Min Shuang Chuan Dong Research Center of Environmental Science and Engineering School of Chemistry and Chemical Engineering Shanxi University Taiyuan 030006 PR China School of Chemistry Shanxi Datong University Datong 037009 PR China

methane gas sensor was fabricated based on electrocatalytic properties of the Pd/MWNT nanocomposites on indium tin oxide （ITO） glass substrates. A linear response for methane was obtained in the range of 0-16% （v/v） with a detection limit of 0.167% （v/ v） and R.S.D. of 4.1%. After 100 times sensing or stable stored more than 12 months in atmosphere, unconspicuous measurable decrease was observed. The response time was less than 60 s at room temperature and ambient pressure. Some common potential interferents in samples such as N2, CO, CO2, ethane, propane, pentane, methanol, ethanol, H2 and NH3 were investigated and all the effects were less than 5% on the response for 3.0% （v/v） methane. The sensor was applied to methane determinations in man-made gas samples, the results are satisfied.

关键词： methane Gas sensor PaUadium/MWNTs Electrocatalysis

Low temperature laser absorption spectra of methane in the near-infrared at 1.65 μm for lower state energy determination

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Chinese Physics B 2012年第1期21卷 260-267页

作者：高伟陈卫东张为俊袁怿谦高晓明 Key Laboratory of Atmospheric Composition and Optical Radiation Chinese Academy of SciencesHefei 230031China Anhui Institute of Optics and Fine Mechanics Chinese Academy of SciencesHefei 230031China Laboratoire de Physicochimie de l'Atmosphère Universitédu Littoral Côte d'Opale189AAv.Maurice Schumann59140 DunkerqueFrance

Direct absorption spectra of the 2v3 band of methane （CH4） from 6038 to 6050 cm 1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback （DFB） diode laser. The cryogenic cell can operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than =t=1 K within 1 hour. In the present work, the CH4 spectra in the range of 6038-6050 cm-1 were recorded at 296, 266, 248, 223, 198, and 176 K. The lower state energy Ett and the rotational assignment of the angular momentum J were determined by a ＂2-low-temperature spectra method＂ using the spectra recorded at 198 and 176 K. The results were compared with the data from the GOSAT and the recently reported results from Campargue and co-workers using two spectra measured at room temperature and 81 K. We demonstrated that the use of a 2-low-temperature spectra method permits one to complete the Ett and J values missed in the previous studies.

关键词： methane laser absorption spectroscopy cryogenic cell low temperature absorption spec-trum