Abstract: The invention relates to a process for producing methanol and to a plant for producing methanol. A first fresh gas suitable for production of methanol is precompressed by a first compressor stage to obtain a second fresh gas. The second fresh gas is merged with a recycle gas stream and further compressed to synthesis pressure in a second compressor stage. Catalytic conversion of the thus obtained synthesis gas stream in a plurality of serially arranged reactor stages with intermediate condensation and separation of the crude methanol reduces the recycle gas amount in the synthesis circuit to such an extent that recycle gas may be directly recycled to the second fresh gas stream, thus ensuring that no recycle gas compressor stage is required and that the total compressor power may be reduced.

Abstract: A system and a process for recovering high concentrations of methane from crude natural gas and solid waste landfill exhaust gas uses a sequential combination of a pressure swing adsorber unit operation to remove volatile organic compounds from the crude feed gas mixture followed by a membrane separation unit operation. The membrane separation uses a membrane which is selectively gas permeable to reject transmission of methane and thus to produce a permeate depleted in methane relative to the feed mixture. The permeate is also free of volatile organic compounds and is recycled to the pressure swing adsorber unit operation to regenerate saturated adsorbers.