MEMBRANE PROCESS FOR OLEFIN SEPARATION

A process is provided to separate a hydrocarbon stream comprising a mixture of light olefins and light paraffins, the process comprising sending the hydrocarbon stream through a pretreatment unit to remove impurities selected from the group consisting of sulfur compounds, arsine, phosphine, methyl acetylene, propadiene, and acetylene to produce a treated hydrocarbon stream; vaporizing the treated hydrocarbon stream to produce a gaseous treated hydrocarbon stream; adding liquid or vapor water to the gaseous treated hydrocarbon stream; then contacting the gaseous treated hydrocarbon stream to a membrane in a membrane system comprising one or more membrane units to produce a permeate stream comprising about 96 to 99.9 wt % light olefins and a retentate stream comprising light paraffins.