In this work,the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by Inverse Gas Chromatography...In this work,the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by Inverse Gas Chromatography(IGC)in the infinite dilution region.The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption(TPD)technique.The interactions between the water and the virgin and modified silica gels were discussed.Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties.The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters.The larger the adsorption parameters and the desorption activation energy were,the interactions between water and virgin and modified silica gels were.展开更多
Gas hydrate is a new technology for energy gas（methane/hydrogen）storage due to its large capacity of gas storage and safe.But industrial application of hydrate storage process was hindered by someproblems.For methan...Gas hydrate is a new technology for energy gas（methane/hydrogen）storage due to its large capacity of gas storage and safe.But industrial application of hydrate storage process was hindered by someproblems.For methane,the main problems are low formation rateand storage capacity,which can be solved by strengthening mass andheat transfer,such as adding additives,stirring,bubbling,etc.Onekind of additives can change the equilibrium curve to reduce the formation pressure of methane hydrate,and the other kind of additivesis surfactant,which can form micelle with water and increase the interface of water-gas.Dry water has the similar effects on the methanehydrate as surfactant.Additionally,stirring,bubbling,and sprayingcan increase formation rate and storage capacity due to mass transferstrengthened.Inserting internal or external heat exchange also canimprove formation rate because of good heat transfer.For hydrogen,the main difficulties are very high pressure for hydrate formed.Tetrahydrofuran（THF）,tetrabutylammonium bromide（TBAB） andtetrabutylammonium fluoride（TBAF） have been proved to be able todecrease the hydrogen hydrate formation pressure significantly.展开更多
Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ （BCNd5） was prepared by pressing followed by sintering. X-ray diffraction （XRD） was used to characterize the phase structure of both ...Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ （BCNd5） was prepared by pressing followed by sintering. X-ray diffraction （XRD） was used to characterize the phase structure of both the powder and the sintered membranes. The microstructure of the sintered membranes was studied by scanning electron microscopy （SEM）. Hydrogen permeation through the BCNd5 membrane was studied using a high temperature permeator. The hydrogen permeation fluxes under wet conditions are higher than those under dry conditions, which is due to H^＋ hopping via surface OH groups. At 925℃, a hydrogen permeation flux of 0.02 mL/min cm^2 was obtained under wet condition, which recommends BCNd5 as a potential material for hydrogen-selective membranes.展开更多
Gas hydrate （or Hydrate）, is also known as cage-shaped inclusion （Clathrate）. It is ice-like, non-chemical cage-shaped crystal compound, composed of the gas and small water molecules on certain conditions （approp...Gas hydrate （or Hydrate）, is also known as cage-shaped inclusion （Clathrate）. It is ice-like, non-chemical cage-shaped crystal compound, composed of the gas and small water molecules on certain conditions （appropriate temperature, pressure, gas saturation, water salinity, pH, etc.）. It can be represented with M-r^H20, in which M stands for gas molecules of hydrate, and n is the number of water molecules. Small-molecule gases CH4, C2H6, C3H8, C4Hlo equivalent homologue, as well as CO2, N2, H2S, etc., can form a single hydrate or multi-component of gas hydrate. Perhaps the most important gas hydrate is natural gas hydrate, which contains more than 99% methane molecules. So the natural gas hydrate is usually called methane hydrate.展开更多
A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ （BSFZ） were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray di...A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ （BSFZ） were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction （HTXRD）. The thermal expansion coefficient of BSFZ is 10.5×10^-6 K^-1, which is lower than that of cobalt-based perovskite materials. The BSFZ membrane was also used to construct reactors for the partial oxidation of methane （POM） to syngas. Results show that the BSFZ membrane can be operated for the POM reaction for more than 100 h without any fractures. The CO selectivity of 97% is obtained. The steady oxygen permeation flux reaches around 2.5 mL/min cm^2 during POM reaction.展开更多
文摘In this work,the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by Inverse Gas Chromatography(IGC)in the infinite dilution region.The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption(TPD)technique.The interactions between the water and the virgin and modified silica gels were discussed.Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties.The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters.The larger the adsorption parameters and the desorption activation energy were,the interactions between water and virgin and modified silica gels were.
基金supported by the National 863 Program (2007AA03Z229)the Fundamental Research Funds for the Central Universities (2009ZM0185)
文摘Gas hydrate is a new technology for energy gas（methane/hydrogen）storage due to its large capacity of gas storage and safe.But industrial application of hydrate storage process was hindered by someproblems.For methane,the main problems are low formation rateand storage capacity,which can be solved by strengthening mass andheat transfer,such as adding additives,stirring,bubbling,etc.Onekind of additives can change the equilibrium curve to reduce the formation pressure of methane hydrate,and the other kind of additivesis surfactant,which can form micelle with water and increase the interface of water-gas.Dry water has the similar effects on the methanehydrate as surfactant.Additionally,stirring,bubbling,and sprayingcan increase formation rate and storage capacity due to mass transferstrengthened.Inserting internal or external heat exchange also canimprove formation rate because of good heat transfer.For hydrogen,the main difficulties are very high pressure for hydrate formed.Tetrahydrofuran（THF）,tetrabutylammonium bromide（TBAB） andtetrabutylammonium fluoride（TBAF） have been proved to be able todecrease the hydrogen hydrate formation pressure significantly.
基金Supported by the National Natural Science Foundation of China （No.20576045）, the Opening Foundation of Zhejiang Provincial Top Key Discipline, and the Program for New Century Excellent Talents in University （No.NCET-06-740）.
基金Natural Science Foundation of Guangdong Province(No.7300769)Program for New Century Excellent Talents in University(No.NECT-07-0307)Fok Ying Tung Education Foundation(No.114019).
文摘Dense mixed proton and electron conducting membrane made of BaCe0.95Nd0.05O3-δ （BCNd5） was prepared by pressing followed by sintering. X-ray diffraction （XRD） was used to characterize the phase structure of both the powder and the sintered membranes. The microstructure of the sintered membranes was studied by scanning electron microscopy （SEM）. Hydrogen permeation through the BCNd5 membrane was studied using a high temperature permeator. The hydrogen permeation fluxes under wet conditions are higher than those under dry conditions, which is due to H^＋ hopping via surface OH groups. At 925℃, a hydrogen permeation flux of 0.02 mL/min cm^2 was obtained under wet condition, which recommends BCNd5 as a potential material for hydrogen-selective membranes.
文摘Gas hydrate （or Hydrate）, is also known as cage-shaped inclusion （Clathrate）. It is ice-like, non-chemical cage-shaped crystal compound, composed of the gas and small water molecules on certain conditions （appropriate temperature, pressure, gas saturation, water salinity, pH, etc.）. It can be represented with M-r^H20, in which M stands for gas molecules of hydrate, and n is the number of water molecules. Small-molecule gases CH4, C2H6, C3H8, C4Hlo equivalent homologue, as well as CO2, N2, H2S, etc., can form a single hydrate or multi-component of gas hydrate. Perhaps the most important gas hydrate is natural gas hydrate, which contains more than 99% methane molecules. So the natural gas hydrate is usually called methane hydrate.
基金supported by Program for New Century Excellent Talents in Chinese Ministry of Education(No.NECT-07-0307)Natural Science Foundation of Guangdong province(No.7300769)+1 种基金Fok Ying Tung Education Foundation(No.114019)New Teacher Fund of Ministry of Education of China(No.20070561032).
文摘A novel cobalt-free perovskite based on Ba0.5Sr0.5Fe0.8Zn0.2O3-δ （BSFZ） were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction （HTXRD）. The thermal expansion coefficient of BSFZ is 10.5×10^-6 K^-1, which is lower than that of cobalt-based perovskite materials. The BSFZ membrane was also used to construct reactors for the partial oxidation of methane （POM） to syngas. Results show that the BSFZ membrane can be operated for the POM reaction for more than 100 h without any fractures. The CO selectivity of 97% is obtained. The steady oxygen permeation flux reaches around 2.5 mL/min cm^2 during POM reaction.
