Preparation And Light Hydrocarbons Permeance Of Zsm-5and P25Hybrid Carbon Membranes

Carbon membrane is prepared by carbonization of polymer membrane in vacuum or inert atmosphere. There are ultramicropores and supermicropores in the carbon membrane, so it can separate gases by the molecular sieve mechanism, which means gases can be separated by their different size. Carbon membrane has the advantages of high gas permeability, high gas selectivity and excellent thermal resistance. However, the gas performance of carbon membrane still has great distance with industrialization, and another drawback of carbon membrane is the great gas permeability loss when stored in air with humidity.We try to overcome this disadvantage by heat treatment. Carbon membrane has usually been researched by the separation of small molecular size gases, and some large gases like light hydrocarbons involved ethene, ethane, propene, propane are rarely related to. Carbon membrane has similar pore size with light hydrocarbons, so it can be a potential application field for carbon membrane.In this paper, the hybrid carbon membranes were prepared by adding ZSM-5zeolite particles and P25nanoparticles into the precursor. The particles can form accumulation pores of themselves and interphacial gaps in carbon matrix, which increase the pore volume of carbon membrane, and diminish the gas diffusion resistance, thereby the gas permeability increase to a large distant. We use TG, SEM and XRD to investigate the thermal stability, hybrid status,and microstructure of carbon membrane. We discussed the effects of particle loading, carbonization temperature and particle size to the gas separation performance of hybrid carbon membranes. This paper also discussed the gas permeability change of carbon membrane stored under RH=40%condition, and the permeance recovery by heat treatment. We investigate the separation performance of light hydrocarbons by zeolite and P25hybrid carbon membranes.The results show that the hybrid particles are well dispersed in carbon membrane. Gas separation test indicate that the adding of particles can increase gas permeability effectively in the range of10-20wt.%.The gas permeability increases by the increase of zeolite loading.Gas permeability decreases and gas selectivities increases under the higher carbonization temperature. With zeolite loading of10wt.%, final carbonization temperature kept700℃, the permeabilities of H2, CO2, O2, N2, CH4, C2H4, C2H6, C3H6, C3H8are1022.8,736.5,180,26.2,16.2,85.3,14.6,28.6,0.21Barrer and the selectivity of O2/N2are6.9. When the carbon membrane was stored by RH=40%, the gas permeability decreased by nearly90%, and120℃heat treatment can recover the permeability to nearly70%. The incorporation of P25particles also can effectively improve the gas performance. Under the prepared condition of20wt.%P25loading, final carbonization temperature kept700℃, the permeabilities of H2, CO2, O2, N2, CH4, C2H4, C2H6, C3H6, C3H8are1769.2,1558.6,410.2,55.5,26.8,92.5,13.1,22.8,0.75Barrer, with O2/N2selectivity of7.4.