Pressure swing adsorption(PSA)is a mature technology,which has been widely used in separation of CH4/N2 mixture gas.Existing researches mostly focus on the separation and purification of mixture gas with low(10%～50%)CH4 content(volume fraction,the same below).Therefore,it is necessary to develop a PSA technology with the carbon molecular sieve as the main adsorbent for CH4/N2 mixture gas with high CH4 content(≥70%).Carbon molecular sieves with high separation coefficient and high adsorption capacity were screened by PSA static experiment and single-tower simulation experiment,and the multiple-towers simulation experiment was used to establish the best process conditions.The best process conditions were obtained by changing parameters such as adsorption times,adsorption pressure and process steps.The results show that,the best multiple-towers simulation process conditions are process steps of 5-1-2/V,adsorption pressure of 0.5 MPa with 70 s,two stages of equalizing pressure,the first equalization pressure pressurization time of 60 s,the second equalization pressure pressurization time of 10 s,inverse releasing to normal pressure with 20 s and vacuum to-0.092 MPa with 70 s.Under the optimal conditions,the CH4 concentration of product gas can be increased to the natural gas pipeline transmission requirements(CH4 content≥95%and N2 content≤5%),and the yield of CH4 is 68%.
国家科技期刊平台
NSTL
万方数据
