Energy-saving Performance of Membrane Separation and Hybrid Membrane Separation/Distillation for Propylene/Propane Binary Systems

The energy-saving performances of membrane separation and hybrid membrane separation/distillation processes for a propylene/propane binary system were investigated using a process simulator, and the effect of stage-cut was assessed on product composition and propylene recovery ratio for one-stage and two-stage membrane separation processes as well as hybrid processes comprising a membrane separation unit and a distillation column. The propylene contents in the feed were 30, 60, 90, and 98 mol%. The optimum separation process based on the propylene content in the feed was based on the simulation results. A hybrid process was suitable for 30 mol% propylene, with the permeate and retentate streams fed into a distillation column after membrane separation of the mixture. High energy-saving performances were achieved for both the hybrid process and the membrane separation process for propylene contents of 60, 90, and 98 mol%.