Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at consta...Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at constant temperature but different equilibrium pressure conditions. Based on these experimental results, the temporal evolution of component fractionation in the field was investigated. The results show that the CO2 concentration in the adsorbed phase is always greater than that in the original gas mixture during the desorption process, while CH4 shows the opposite characteristics. This has confirmed that CO2 , with a greater adsorption ability has a predominant position in the competition with CH4 under different pressures. Where gas drainage is employed, the ratio of CO2 to CH4 varies with time and space in floor roadways used for gas drainage, and in the ventilation air in Nos.1 and 2 coal seams, which is consistent with laboratory results.展开更多
Different gas adsorption isotherm experiments were carried out on the coal samples from Jincheng district, including N2, CH4, CO2, as well as the binary-component gas of CH4-N2 and CH4-CO2 of three different concentra...Different gas adsorption isotherm experiments were carried out on the coal samples from Jincheng district, including N2, CH4, CO2, as well as the binary-component gas of CH4-N2 and CH4-CO2 of three different concentrations. In the binary-component gas adsorption isotherm experiments, the gas component with higher adsorption ability is adsorbed firstly. Thus the result in its relative concentration in the free phase shows a trend of decrease first and then increase, whereas the relative concentration of the gas component with lower adsorption ability shows a trend of increase first and then decrease. In the adsorption phrase, the relative concentration of the gas component with higher adsorption ability increases gradually, and the relative concentration of the gas component with lower adsorption ability decreases gradually. In the adsorption competition of the binary-component gas, the adsorption rate of the gas component with higher adsorption ability shows a trend of rapidity at first then slowness, but the adsorption rate of the gas component with lower adsorption ability shows a trend of slowness at first then rapidity. The component fractionation effect in the binary-component gas adsorption isotherm experiments is caused by the difference of the adsorption ability of coal of different gas components.展开更多
The determination of isotherm and prediction of retention values are the basis of the optimization of separation conditions of preparative chromatography.In this paper,the isotherms of ginsenoside Rg1 and Re from Pana...The determination of isotherm and prediction of retention values are the basis of the optimization of separation conditions of preparative chromatography.In this paper,the isotherms of ginsenoside Rg1 and Re from Panax ginseng were studied.Ginsenoside Rg1 and Re were prepared by chromatography column from Panax ginseng raw material,and the isotherms of ginsenoside Rg1 and Re were determined by frontal analysis(FA) on spherical C18 solid phase.The adsorption parameters G and b were set based on the competitive Langmuir model.In the mean time,the retention time of ginsenoside Re was obtained with the results of nonlinear chromatography theory.The calculated retention time were compared with that of experimental results with average relative error 3.68%.Additionally,some problems related to fitting based on the competitive Langmuir model were found and discussed.展开更多
基金financially supported by the Natural Science Foundation for the Youth of China (No. 41202118)the Fundamental Research Funds for the Central Universities (No.2012QNB03)
文摘Adsorption-desorption experiments on CO2-CH4 gas mixtures with varying compositions have been conducted to study the fractionation characteristics of CO2-CH4 on Haishiwan coal samples. These were carried out at constant temperature but different equilibrium pressure conditions. Based on these experimental results, the temporal evolution of component fractionation in the field was investigated. The results show that the CO2 concentration in the adsorbed phase is always greater than that in the original gas mixture during the desorption process, while CH4 shows the opposite characteristics. This has confirmed that CO2 , with a greater adsorption ability has a predominant position in the competition with CH4 under different pressures. Where gas drainage is employed, the ratio of CO2 to CH4 varies with time and space in floor roadways used for gas drainage, and in the ventilation air in Nos.1 and 2 coal seams, which is consistent with laboratory results.
文摘Different gas adsorption isotherm experiments were carried out on the coal samples from Jincheng district, including N2, CH4, CO2, as well as the binary-component gas of CH4-N2 and CH4-CO2 of three different concentrations. In the binary-component gas adsorption isotherm experiments, the gas component with higher adsorption ability is adsorbed firstly. Thus the result in its relative concentration in the free phase shows a trend of decrease first and then increase, whereas the relative concentration of the gas component with lower adsorption ability shows a trend of increase first and then decrease. In the adsorption phrase, the relative concentration of the gas component with higher adsorption ability increases gradually, and the relative concentration of the gas component with lower adsorption ability decreases gradually. In the adsorption competition of the binary-component gas, the adsorption rate of the gas component with higher adsorption ability shows a trend of rapidity at first then slowness, but the adsorption rate of the gas component with lower adsorption ability shows a trend of slowness at first then rapidity. The component fractionation effect in the binary-component gas adsorption isotherm experiments is caused by the difference of the adsorption ability of coal of different gas components.
基金国家重大科研仪器研制项目(No.51427804)国家重点研发计划项目(No.2016YFC0801402+3 种基金No.2016YFC0801404)supported by the National Major Scientific Instruments Development Project(51427804)the State Key Project of Research and Development Plan(2016YFC08014022016YFC0801404)
文摘The determination of isotherm and prediction of retention values are the basis of the optimization of separation conditions of preparative chromatography.In this paper,the isotherms of ginsenoside Rg1 and Re from Panax ginseng were studied.Ginsenoside Rg1 and Re were prepared by chromatography column from Panax ginseng raw material,and the isotherms of ginsenoside Rg1 and Re were determined by frontal analysis(FA) on spherical C18 solid phase.The adsorption parameters G and b were set based on the competitive Langmuir model.In the mean time,the retention time of ginsenoside Re was obtained with the results of nonlinear chromatography theory.The calculated retention time were compared with that of experimental results with average relative error 3.68%.Additionally,some problems related to fitting based on the competitive Langmuir model were found and discussed.
