US Patent 7879919 Production of hydrocarbons from natural gas

A process for producing hydrocarbons from natural gas includes, in a cryogenic separation stage, cryogenically separating the natural gas to produce at least a methane stream and natural gas liquids, in a reforming stage, reforming the methane stream to produce a synthesis gas which includes at least CO and H2, and in a Fischer-Tropsch hydrocarbon synthesis stage, converting at least some of the CO and H2 into a Fischer-Tropsch product which includes hydrocarbons. A Fischer-Tropsch tail gas which includes at least CO and H2, methane and heavier than methane hydrocarbons, is separated from the Fischer-Tropsch product in a Fischer-Tropsch product separation stage. At least a portion of the Fischer-Tropsch tail gas is recycled to the cryogenic separation stage, where the Fischer-Tropsch tail gas is cryogenically separated into two or more streams.