Process and system for recovering natural gas liquids (NGL) from flare gas using joule-thomson (J-T) cooling and membrane separation

摘要

A process and system for recovering natural gas liquids (NGL) using a combination of J-T cooling and membrane separation. The process involves compressing, separating, and cooling a flare gas stream comprising at least methane and C₃₊ hydrocarbons prior to being introduced to a J-T valve. The cooled stream exiting the J-T valve is further separated, producing a NGL product stream and an uncondensed gas stream. The uncondensed gas stream is directed to a membrane separation step, which results in a C₃₊ hydrocarbon enriched stream and a C₃₊ hydrocarbon depleted stream. The C₃₊ hydrocarbon enriched stream may be recycled back to the process to recover more NGL.