Preparation Of PPESK/PEI Hollow Fiber Composite Membrane For Propylene And Propane Separation

Nowadays,more and more attentions have been paid on separation process of olefins and paraffins by using gas separation membranes technique.Using Poly(phthalazinone ether sulfone ketone)(PPESK) and polyetherimide(PEI) as membrane material,DMAc as solvent,γ-butyrolactone as nonsolvent,the asymmetric hollow fiber base membranes were formed through dry/wet spinning in this paper.NaX zeolite filled PDMS composite membranes and Co²⁺ facilitated transport composite membranes were prepared successfully,the propylene/propane separation performance of composite membranes was studied.The structure research and character analysis Were made with SEM,gas permeability and separation coefficient.The structure and performance of the PPESK/PEI hollow fiber base membranes prepared based on the phase separation behavior had been researched.The effect of polymer concentrations,nonsolvent types and contents,air gap length,casting solution temperature, coagulant media temperature on the structure and performance of the PPESK/PEI hollow fiber base membranes had been systemically researched.The results of experiment showed, increase in polymer concentrations can raise membrane permeation rate,membrane formed with GBL as nonsolvent had compact cortex and increase in GBL contents can raise permeation rate and decrease separation coefficient.The increase in air gap length in certain extent can improve membrane separation performance,the high casting solution temperature and low coagulant media temperature can improve the membrane separation performance and decrease membrane permeation rate.Summary from research,the preparation technology of membranes for propylene/propane separation was got.The PPESK/PEI hollow fiber composite membranes were prepared by vacuum coating NaX zeolite-filled PDMS solution,that the NaX zeolite is the selective adsored to propylene over propane.The effect of curing temperature,curing time,coating time,NaX zeolite loadings,second-coating,operational pressure and temperature on the separation performance of composite membranes were systemically studied.The results of experiment showed,the composite membranes after second-coating got the best separation performance when curing temperature was 80℃,curing time was 80 min,coating time was 6 min,NaX zeolite loadings was 30%,operational pressure was 100 KPa and operational temperature was 60℃,and separation coefficient reached 3.84,propylene permeation rate was 435 GPU.The facilitated transport composite membrane was successfully prepared by inner-coating coating PVA and complexing cobalt ion.The effect of PVA content,Co²⁺ carder content, curing temperature and anion types on the separation performance of composite membranes were systemically studied.The results of experiment showed,the composite membranes got the best separation performance by using Co(CH₃COO)₂ when PVA content was 6%,[Co²⁺]: [-OH]was 3:4 and curing temperature was 60℃,and separation coefficient reached 2.05, propylene permeation rate was 156.8 GPU.