Non-oxidative conversion of methane to olefins,aromatics and hydrogen(MTOAH) has been reported recently over metal single sites such as iron and platinum.The reaction was proposed to involve catalytic activation of me...Non-oxidative conversion of methane to olefins,aromatics and hydrogen(MTOAH) has been reported recently over metal single sites such as iron and platinum.The reaction was proposed to involve catalytic activation of methane followed by gas phase C-C coupling of methyl radicals.This study using H atom Rydberg Tagging time-of-flight technique provides direct experimental evidence for the formation of hydrogen radicals during MTOAH reaction over a catalytic quartz wall reactor containing embedded iron species(denoted as Fe-reactor).Fe-reactor gives 7.3% methane conversion at 1273 K with 41.2% selectivity toward C2(ethane,ethylene and acetylene) and 31.8% toward BTX(benzene,toluene and xylene),respectively.The enhancing effects of hydrogen radicals on overall MTOAH performance are validated by cofeeding hydrogen donor benzene,which provides an additional route of methane activation apart from catalytic activation.展开更多
In this work,several experiments were conducted at isobaric and isothermal condition in a CSTR reactor to study the kinetics of methane hydrate formation and dissociation.Experiments were performed at five temperature...In this work,several experiments were conducted at isobaric and isothermal condition in a CSTR reactor to study the kinetics of methane hydrate formation and dissociation.Experiments were performed at five temperatures and three pressure levels(corresponding to equilibrium pressure).Methane hydrate formation and dissociation rates were modeled using mass transfer limited kinetic models and mass transfer coefficients for both formation and dissociation were calculated.Comparison of results,shows that mass transfer coefficients for methane hydrate dissociation are one order greater than formation conditions.Mass transfer coefficients were correlated by polynomials as relations of pressure and temperature.The results and the method can be applied for prediction of methane production from naturally occurring methane hydrate deposits.展开更多
A co-reaction of methane with methanol over zeolite catalysts has emerged as a new approach to the long-standing challenge of methane transformation.However,the effect of catalyst acid properties on the co-reaction ha...A co-reaction of methane with methanol over zeolite catalysts has emerged as a new approach to the long-standing challenge of methane transformation.However,the effect of catalyst acid properties on the co-reaction has been rarely studied.In this study,a series of HZSM-5 zeolites with comparable diffusion abilities and various acidities were synthesized directly through steaming with 100%water vapor at 693 K.The co-reaction of methane and methanol was subsequently evaluated.Br?nsted acidity at 0.262 mmol/g was detected to reach the maximum methane conversion of 5.42%at 673 K,which was also the odd point in the relationship between acid concentration and C4 hydrogen transfer index.Moreover,the influence of methanol feed was investigated over parent and steamed ZSM-5 catalyst,with results showing that excessive acid sites or methanol molecules reduce methane conversion.It is proposed that acid sites adsorbed with methanol molecules construct the methane activation sites.Hence,a proper design of zeolite acidity should be achieved to obtain higher methane conversion in the co-reaction process.展开更多
基于清单方法对中国的甲烷(CH_(4))及氧化亚氮(N_(2)O)等农业源非二氧化碳(CO_(2))温室气体(GHG)排放情况进行核算研究,通过引入Tapio弹性脱钩理论和对数平均迪氏指数(LMDI)方法研究了中国农业源CH4和N_(2)O排放的影响因素.结果表明:①1...基于清单方法对中国的甲烷(CH_(4))及氧化亚氮(N_(2)O)等农业源非二氧化碳(CO_(2))温室气体(GHG)排放情况进行核算研究,通过引入Tapio弹性脱钩理论和对数平均迪氏指数(LMDI)方法研究了中国农业源CH4和N_(2)O排放的影响因素.结果表明:①1980—2018年中国农业源CH4和N2O排放量由0.56×10^(9) t CO_(2⁃eq)上升至0.73×10^(9) t CO_(2⁃eq);②1980—2018年中国农业源CH4和N2O排放随着农业总产值增长而缓慢增加,整体呈弱脱钩状态,但其脱钩状态稳定性较差;③从LMDI因素分解角度看,经济因素和人口规模因素对中国农业源CH_(4)和N_(2)O排放呈正效应,经济因素影响最大;效率因素和结构因素均对中国农业源CH4和N2O排放有减缓作用,其中,效率因素为主要抑制因素;④结构因素、效率因素和人口规模因素对脱钩努力的影响程度为效率因素>结构因素>人口规模因素.展开更多
We report a microporous aluminum-based metal-organic framework(MOF),BUT-22 for high methane(CH_(4)),hydrogen(H_(2)),and carbon dioxide(CO2)storage.At 296 K and 80 bar,BUT-22 exhibits a high gravimetric CH4 storage cap...We report a microporous aluminum-based metal-organic framework(MOF),BUT-22 for high methane(CH_(4)),hydrogen(H_(2)),and carbon dioxide(CO2)storage.At 296 K and 80 bar,BUT-22 exhibits a high gravimetric CH4 storage capacity of 530 cm^(3)(STP)/g(0.379 g/g).BUT-22 also has a high gravimetric H_(2)storage capacity of 12 wt.%at 100 bar and 77 K.In addition,the CO_(2)adsorption studies revealed that BUT-22 exhibits a high absolute gravimetric CO2 uptake of 1.7 g/g at 296 K and 40 bar.展开更多
基金supported by the Chinese Academy of Sciences (XDB10020202)the National Natural Science Foundation of China (Grant Nos. 21621063, 21425312, 21761132035)the National Key R&D Program of China (2017YFA0403402)。
文摘Non-oxidative conversion of methane to olefins,aromatics and hydrogen(MTOAH) has been reported recently over metal single sites such as iron and platinum.The reaction was proposed to involve catalytic activation of methane followed by gas phase C-C coupling of methyl radicals.This study using H atom Rydberg Tagging time-of-flight technique provides direct experimental evidence for the formation of hydrogen radicals during MTOAH reaction over a catalytic quartz wall reactor containing embedded iron species(denoted as Fe-reactor).Fe-reactor gives 7.3% methane conversion at 1273 K with 41.2% selectivity toward C2(ethane,ethylene and acetylene) and 31.8% toward BTX(benzene,toluene and xylene),respectively.The enhancing effects of hydrogen radicals on overall MTOAH performance are validated by cofeeding hydrogen donor benzene,which provides an additional route of methane activation apart from catalytic activation.
文摘In this work,several experiments were conducted at isobaric and isothermal condition in a CSTR reactor to study the kinetics of methane hydrate formation and dissociation.Experiments were performed at five temperatures and three pressure levels(corresponding to equilibrium pressure).Methane hydrate formation and dissociation rates were modeled using mass transfer limited kinetic models and mass transfer coefficients for both formation and dissociation were calculated.Comparison of results,shows that mass transfer coefficients for methane hydrate dissociation are one order greater than formation conditions.Mass transfer coefficients were correlated by polynomials as relations of pressure and temperature.The results and the method can be applied for prediction of methane production from naturally occurring methane hydrate deposits.
基金Project supported by the National Natural Science Foundation of China(No.U1663222)。
文摘A co-reaction of methane with methanol over zeolite catalysts has emerged as a new approach to the long-standing challenge of methane transformation.However,the effect of catalyst acid properties on the co-reaction has been rarely studied.In this study,a series of HZSM-5 zeolites with comparable diffusion abilities and various acidities were synthesized directly through steaming with 100%water vapor at 693 K.The co-reaction of methane and methanol was subsequently evaluated.Br?nsted acidity at 0.262 mmol/g was detected to reach the maximum methane conversion of 5.42%at 673 K,which was also the odd point in the relationship between acid concentration and C4 hydrogen transfer index.Moreover,the influence of methanol feed was investigated over parent and steamed ZSM-5 catalyst,with results showing that excessive acid sites or methanol molecules reduce methane conversion.It is proposed that acid sites adsorbed with methanol molecules construct the methane activation sites.Hence,a proper design of zeolite acidity should be achieved to obtain higher methane conversion in the co-reaction process.
文摘基于清单方法对中国的甲烷(CH_(4))及氧化亚氮(N_(2)O)等农业源非二氧化碳(CO_(2))温室气体(GHG)排放情况进行核算研究,通过引入Tapio弹性脱钩理论和对数平均迪氏指数(LMDI)方法研究了中国农业源CH4和N_(2)O排放的影响因素.结果表明:①1980—2018年中国农业源CH4和N2O排放量由0.56×10^(9) t CO_(2⁃eq)上升至0.73×10^(9) t CO_(2⁃eq);②1980—2018年中国农业源CH4和N2O排放随着农业总产值增长而缓慢增加,整体呈弱脱钩状态,但其脱钩状态稳定性较差;③从LMDI因素分解角度看,经济因素和人口规模因素对中国农业源CH_(4)和N_(2)O排放呈正效应,经济因素影响最大;效率因素和结构因素均对中国农业源CH4和N2O排放有减缓作用,其中,效率因素为主要抑制因素;④结构因素、效率因素和人口规模因素对脱钩努力的影响程度为效率因素>结构因素>人口规模因素.
基金the National Natural Science Foundation of China(Nos.21971038,21975044,21805039,21673039,573042)the Fujian Science and Technology Department(Nos.2019H6012,2018J07001)+1 种基金the China Postdoctoral Science Foundation(No.2018M642556)the Welch Foundation(No.AX-1730).
文摘We report a microporous aluminum-based metal-organic framework(MOF),BUT-22 for high methane(CH_(4)),hydrogen(H_(2)),and carbon dioxide(CO2)storage.At 296 K and 80 bar,BUT-22 exhibits a high gravimetric CH4 storage capacity of 530 cm^(3)(STP)/g(0.379 g/g).BUT-22 also has a high gravimetric H_(2)storage capacity of 12 wt.%at 100 bar and 77 K.In addition,the CO_(2)adsorption studies revealed that BUT-22 exhibits a high absolute gravimetric CO2 uptake of 1.7 g/g at 296 K and 40 bar.