|
In natural gas extraction and transportation process , often mixed with carbon dioxide gas , and if you can not carbon dioxide removal , will affect the quality of the natural gas , and often cause pipeline corrosion , and will reduce the heat of combustion of natural gas . Membrane carbon dioxide removal is a new separation method , compared with the traditional method , which has a simple and efficient process , energy conservation , separation is good , etc. . In this paper, the PDMS / PEI composite membrane separation CO2/CH4 mixed gas to study the impact of different process conditions on the effects of membrane separation . The diffusion coefficient of carbon dioxide , methane, nitrogen was measured using the transient method , the solubility coefficient and the permeability coefficient , and studied the diffusion coefficient of the gas of the three pure components , the solubility coefficient and permeability coefficient of variation of the temperature and pressure . The results show that , in the gas permeation through the process of separation composite membrane , the permeability coefficients of carbon dioxide is greater than the permeability coefficient of the methane and nitrogen ; coefficient of solubility of carbon dioxide is also greater than the solubility coefficient of the methane and nitrogen , but the diffusion coefficient of carbon dioxide is less than methane and nitrogen diffusion coefficient . This shows that the gas dissolved in the process of the film , through the separation of the composite membrane permeation process and subject to its control . Further, increasing the feed -side pressure or lowering the temperature of the raw material gas , is conducive to the carbon dioxide gas separation composite membranes . PDMS / PEI Flat composite membrane for separating CO2/CH4 mixed gas were measured under different process conditions the carbon dioxide permeation rate and separation factor and found that: the content of the carbon dioxide in the raw material gas , increasing the temperature of the raw material gas or to reduce its pressure are conducive to an increase in the carbon dioxide permeation rate ; raw material gas flow rate is relatively small impact on the carbon dioxide permeation rate ; reduce the pressure of the raw material gas , its flow rate is increased or raise its temperature can improve carbon dioxide separation factor . According to the known solution - diffusion model , comparative mapping , simulation and experimental values ??of CO2/CH4 mixed gas system simulation under different conditions , and be drawn to this model can be approximated with the experimental phenomenon . And another new mixed gas system C3H8/CH4 are simulated, using the mathematical model to forecast the trend of the propane in this system , the permeation rate and the separation factor .
|