US Patent 10139157 NGL recovery from natural gas using a mixed refrigerant

An NGL recovery facility for separating ethane and heavier (C2+) components from a hydrocarbon-containing feed gas stream that utilizes a single, closed-loop mixed refrigerant cycle. The vapor and liquid portions of the feed gas stream are isenthalpically flashed and the resulting expanded streams are introduced into the NGL recovery column. Optionally, a second vapor stream can be flashed and then introduced into the recovery column at the same or lower separation stage than the flashed liquid stream. As a result, the NGL recovery facility can optimize C2+ recovery with compression costs.