Preparation Of Tubular Composite Carbon Membrane For Gas Separation

The carbon membranes have attracted much attention recently,which showed great potential in the area of gas separation for their super microporous distinguishing size of gas molecules, good thermal and chemical resistance. However, they are still commercially unavailable because of these problems, i.e. poor mechanism,high-cost, and low gas permeance Therefore, it is urgent to improve the composite between surpport and precursor,optimize preparation technology and improve gas permeation.The composite carbon membranes were prepared by coating the PAA and PPESK solution on the coal-based supports.Effects of different pore size of supports and preparation conditions on the gas separation performance of composite carbon membranes were investigated. The optimum conditions of coating technology to prepare PI and ppesk based carbon membranes was determined and was that the concentration of the coating solution are 16wt%, 15wt% and coating times are three,two,respectively..In ordered to improve the composite between surpport and precursor, we chose one nonionic surfactant as a modifier Effects of different molecular weight and amount of additive on the gas separation performance of composite carbon membranes were investigated. The modifier showed the function of improving the composite between support and precursor and increased the permeation rates at the same time. The ideal separation factor of O₂/N₂ for the PI and PPESK based composite carbon membranes reached 9.34 and 7.69, respectively.Aiming at improving the permeation rates of composite carbon membranes, interlayer with ordered structure had been prepared on the surface of supports by using ordered mesoporous material as precursors. Effects of kinds and amount of template,kinds of catalyst,reaction temperatures and kinds of precursors materials on the structure of the fabrication material, XRD,TEM,FTIR and TG were used to characterize the material.The optimum process was determined and was that mol(F127):mol(R/F)=0.0081. The results indicated that the largest pore size of the surface of the bituminous coal support and mixed coal support decreased from 0.38,0.53μm to 0.299,0.28μm by preparing of the interlayer. The N₂ permeation rate of modified mixed coal supports reached 10^-8m³Â·m^-2·s^-1·Pa^-1which was four times as great as the N₂ permeation rate of bituminous coal supports.