Processes for natural gas production are described. The processes involve combining a membrane separation system and a thermal oxidizing system. The high and low hydrocarbon permeate streams from the membrane separation system are introduced into the thermal oxidizing system separately. The high hydrocarbon permeate stream provides fuel for the thermal oxidizing system, allowing a reduction in external fuel usage. The reduction in total fuel required yields increased gas production for the total plant. A solvent based acid gas removal system can optionally be included.

The present invention relates to a process for oxidative coupling of methane (OCM), comprising the steps of: (a) contacting, in a reactor, oxygen and methane with an OCM catalyst, resulting in a reactor effluent comprising ethylene, ethane, methane, carbon dioxide and water; (b) cooling the reactor effluent to obtain a liquid stream comprising water and a gas stream comprising ethylene, ethane, methane and carbon dioxide; (c) removing carbon dioxide from at least a part of the gas stream comprising ethylene, ethane, methane and carbon dioxide resulting in a gas stream comprising ethylene, ethane and methane; (d) passing at least a part of the gas stream comprising ethylene, ethane and methane as obtained in step (c) through a membrane, preferably a membrane comprising metal cations, more preferably a membrane comprising silver (I) ions (Ag.sup.+ ions) or copper (I) ions (Cu.sup.+ ions), to obtain a stream comprising ethane and a stream comprising ethylene.

A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a pressure measurement device, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO.sub.2 from CH.sub.4 to permeates enriched in CO.sub.2 and retentates enriched in CH.sub.4, respectively. A temperature of the first retentate is adjusted at an inlet of the second membrane separation unit with at least one heat exchanger as a function of the measured CH.sub.4 concentration in such a way so as to reduce the determined difference.

A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a pressure measurement device, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO.sub.2 from CH.sub.4 to permeates enriched in CO.sub.2 and retentates enriched in CH.sub.4, respectively. The at least one valve adjusts the number of membranes combined and connected to the flow of gas entering into at least one of the membrane separation units as a function of the pressure recorded by the pressure measurement device.

Installation for membrane permeation treatment of feed gas containing methane and carbon dioxide that includes first, second, and third membrane separation units. The permeate from the first membrane separation unit is fed to the third membrane separation unit and the retentate from the first membrane separation unit is fed to the second membrane separation unit. The aspiration pressure of the second permeate is adjusted with a compressor according to the aspiration pressure of the second permeate before recycling thereof to the feed gas flow fed to the first membrane separation unit.

A reactor for converting hydrogen sulfide into hydrogen gas and sulfur.

A method for separating a raw feed gas stream using a plurality of membrane separation stages includes separating a pressurized feed gas stream into a first nonpermeate stream and a first permeate stream, compressing the first permeate stream to form a compressed first permeate stream, separating the compressed first permeate stream into a second nonpermeate stream and a second permeate stream, separating the second permeate stream into a third nonpermeate stream and a third permeate stream, combining the third nonpermeate stream with a raw feed gas stream to form a combined feed stream, compressing the combined feed stream to form a compressed combined feed stream, and combining the second nonpermeate stream with the compressed combined feed stream to form the pressurized feed gas stream.

A process for producing biomethane by scrubbing a biogas feed stream including introducing a feed gas stream into a pretreatment unit wherein the gas stream is partially separated from a CO.sub.2 stream and an oxygen stream, thereby producing a CO.sub.2-depleted gas stream, which is compressed, thereby producing a pressurized CO.sub.2-depleted gas stream; separating the pressurized CO.sub.2-depleted gas stream by cryogenic separation by introducing the pressurized CO.sub.2-depleted gas stream into a distillation column thereby producing a nitrogen stream and a CH.sub.4-enriched stream, recovering a pressurized CH.sub.4-enriched stream by pumping the CH.sub.4-enriched stream; wherein the separation of the CO.sub.2 stream and the oxygen stream from the feed gas stream is performed by a unit comprising at least two separating membrane stages in order that the CO.sub.2-depleted gas stream comprises between 0.3 mol % and 2 mol % of CO.sub.2.

A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a pressure measurement device, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO.sub.2 from CH.sub.4 to permeates enriched in CO.sub.2 and retentates enriched in CH.sub.4, respectively. A temperature of the first retentate is adjusted at an inlet of the second membrane separation unit with at least one heat exchanger as a function of the measured CH.sub.4 concentration in such a way so as to reduce the determined difference.

A multistage membrane system and a process for treating a gas stream is provided in which the multistage membrane system comprises at least two membrane units wherein a first stage membrane unit comprises a polymeric membrane and a second membrane unit comprises a microporous zeolitic inorganic membrane or a combination of a microporous zeolitic inorganic membrane and a polymeric membrane.