A tubular commercial mesoporous support was used to prepare a Pt impregnated membrane using the reservoir method and tested for moderate temperature (300°C) gas transport of hydrogen (H2), helium (He) and nitroge...A tubular commercial mesoporous support was used to prepare a Pt impregnated membrane using the reservoir method and tested for moderate temperature (300°C) gas transport of hydrogen (H2), helium (He) and nitrogen (N2) gas molecules. H2 and N2 gas permeation of 6.1 and 4.5 l/min at 1.0 barg feed pressure and 25°C respectively was obtained from the support. On the other hand, H2 and N2 gas permeation of 4.6 and 1.7 l/min at 1.0 barg feed pressure and 25°C respectively was also obtained from the Pt membrane. Selectivity of H2 over He of 1.96 at 300°C and 1.6 barg for the Pt membrane was obtained and found to be higher than that of the theoretical Knudsen selectivity. Also, a selectivity of H2 over N2 of 2.72 at 25°C and 1.0 barg was obtained and found to be close to that of the theoretical Knudsen selectivity. The gas permeation and the selectivity performance of the membrane were evaluated.展开更多
In this work, membrane evaluation, gas permeation properties and characterisation have been presented. A silica composite membrane was prepared, characterized and used for the permeation tests with four carrier gases ...In this work, membrane evaluation, gas permeation properties and characterisation have been presented. A silica composite membrane was prepared, characterized and used for the permeation tests with four carrier gases to determine the most suitable carrier gas for enhancing the analysis of esterification product with gas chromatograph. The carrier gases used for the permeation tests were carbon dioxide (CO2), argon (Ar), helium (He) and nitrogen (N2). The permeation analysis was carried out between the gauge pressure range of 0.10 - 1.00 bar and temperature of 60℃. The gas flow rate was found to increase with respect to gauge pressure. The order of the gas flow rate with respect to the gauge pressure was Ar > CO2 > He > N2. The surface morphology and elemental composition of the membrane were analysed using scanning electron microscopy coupled with energy dispersive analysis of x-ray (the Zeiss EVO LS10). The SEM results exhibited a defect-free surface while the EDAX results identified different elements on the spectra including titanium (Ti), silicon (Si) and oxygen (O). Liquid nitrogen adsorption method (Quantachrome 2013 model) was used for the surface area and pore size distribution analysis. The Brunauer-Emmette-Teller (BET) surface area results of the 5th and 6th dip-coated membranes were 1.497 and 0.253 m2/g respectively, while the Barrette-Joyner-Halender (BJH) curves gave a pore size of 4.184 and 4.180 nm respectively for the 5th and 6th dip-coated membranes indicating a mesoporous structure. The BET curve exhibited a type IV isotherm. The BJH curve of the 6th dip-coated membrane showed a significant reduction in flow rate after the modification process. The membrane recorded a permeance in the range of to . The permeance relationship with the inverse square root of the gas molecular weight showed a linear proportionality with the flow of carrier gases confirming Knudsen flow mechanism of gas transport.展开更多
The dip-coating method has been used to prepare silica membrane. The gas flow rate relationship with the gauge pressure showed a Knudsen type of mechanism of gas transport. The flux was found to decrease with respect ...The dip-coating method has been used to prepare silica membrane. The gas flow rate relationship with the gauge pressure showed a Knudsen type of mechanism of gas transport. The flux was found to decrease with respect to temperature indicating non-activation mechanism of transport through the membrane. The order of the gas kinetic diameter with respect to the gas flow rate was He > Ar > CO2 > N2 confirming a molecular sieving mechanism of gas transport. The characterisation of the resin catalysts was carried out using scanning electron microscopy (SEM). The SEM morphology of the Amberlyst 16 resin catalysts showed a defect-free surface before esterification process. Amberlyst 15 catalyst exhibited some defect on the surface indicating a lower resistance to lactic acid and decomposition at higher temperature after the esterification process at 60°C. The order of the gas viscosity with respect to the gas flux was N2 > Ar > CO2 > He.展开更多
文摘A tubular commercial mesoporous support was used to prepare a Pt impregnated membrane using the reservoir method and tested for moderate temperature (300°C) gas transport of hydrogen (H2), helium (He) and nitrogen (N2) gas molecules. H2 and N2 gas permeation of 6.1 and 4.5 l/min at 1.0 barg feed pressure and 25°C respectively was obtained from the support. On the other hand, H2 and N2 gas permeation of 4.6 and 1.7 l/min at 1.0 barg feed pressure and 25°C respectively was also obtained from the Pt membrane. Selectivity of H2 over He of 1.96 at 300°C and 1.6 barg for the Pt membrane was obtained and found to be higher than that of the theoretical Knudsen selectivity. Also, a selectivity of H2 over N2 of 2.72 at 25°C and 1.0 barg was obtained and found to be close to that of the theoretical Knudsen selectivity. The gas permeation and the selectivity performance of the membrane were evaluated.
文摘In this work, membrane evaluation, gas permeation properties and characterisation have been presented. A silica composite membrane was prepared, characterized and used for the permeation tests with four carrier gases to determine the most suitable carrier gas for enhancing the analysis of esterification product with gas chromatograph. The carrier gases used for the permeation tests were carbon dioxide (CO2), argon (Ar), helium (He) and nitrogen (N2). The permeation analysis was carried out between the gauge pressure range of 0.10 - 1.00 bar and temperature of 60℃. The gas flow rate was found to increase with respect to gauge pressure. The order of the gas flow rate with respect to the gauge pressure was Ar > CO2 > He > N2. The surface morphology and elemental composition of the membrane were analysed using scanning electron microscopy coupled with energy dispersive analysis of x-ray (the Zeiss EVO LS10). The SEM results exhibited a defect-free surface while the EDAX results identified different elements on the spectra including titanium (Ti), silicon (Si) and oxygen (O). Liquid nitrogen adsorption method (Quantachrome 2013 model) was used for the surface area and pore size distribution analysis. The Brunauer-Emmette-Teller (BET) surface area results of the 5th and 6th dip-coated membranes were 1.497 and 0.253 m2/g respectively, while the Barrette-Joyner-Halender (BJH) curves gave a pore size of 4.184 and 4.180 nm respectively for the 5th and 6th dip-coated membranes indicating a mesoporous structure. The BET curve exhibited a type IV isotherm. The BJH curve of the 6th dip-coated membrane showed a significant reduction in flow rate after the modification process. The membrane recorded a permeance in the range of to . The permeance relationship with the inverse square root of the gas molecular weight showed a linear proportionality with the flow of carrier gases confirming Knudsen flow mechanism of gas transport.
文摘The dip-coating method has been used to prepare silica membrane. The gas flow rate relationship with the gauge pressure showed a Knudsen type of mechanism of gas transport. The flux was found to decrease with respect to temperature indicating non-activation mechanism of transport through the membrane. The order of the gas kinetic diameter with respect to the gas flow rate was He > Ar > CO2 > N2 confirming a molecular sieving mechanism of gas transport. The characterisation of the resin catalysts was carried out using scanning electron microscopy (SEM). The SEM morphology of the Amberlyst 16 resin catalysts showed a defect-free surface before esterification process. Amberlyst 15 catalyst exhibited some defect on the surface indicating a lower resistance to lactic acid and decomposition at higher temperature after the esterification process at 60°C. The order of the gas viscosity with respect to the gas flux was N2 > Ar > CO2 > He.
