Patent ID: 8475567

Claim:
A process comprising separating propane and propylene in a distillation column and at least one separation unit constituted by several membrane modules operating in series, said separation unit or units being placed either upstream, or downstream, or upstream and downstream of the distillation column, said membrane module or modules comprises polymer membranes having a propylene permeability greater than 0.1 barrer and propylene/propane selectivity greater than 5, said membrane module or modules operating under the following pervaporation conditions provided at the inlet to each membrane module: feedstock pressure comprised between 20 and 47 bar and feedstock temperature between 20° C. and 92° C., said separation unit or units operating with a difference in pressure such that a permeate is at a minimum pressure of 10 bar and wherein the permeate is reinjected either upstream, or downstream, or upstream and downstream of the distillation column in vapour phase.