A natural gas fueling system supplies methane gas to an engine and includes a filter assembly. The filter assembly includes a gas inlet configured to receive inlet gas and a methane permeable filter configured to separate methane gas and first contaminant gases from the inlet gas. The natural gas fueling system also includes a reformer apparatus configured to convert the first contaminant gases into a reformed gas stream including methane gas. The reformed gas is supplied to the gas inlet and is recirculated through the filter assembly to extract the methane gas from the reformed gas stream.

The present invention provides a method for separating high purity methane gas from biogas, which comprises the steps of: compressing and cooling biogas (step 1); and separating carbon dioxide by introducing the biogas compressed and cooled in step 1 into a four-stage polymer separation membrane system in which the residue stream of the first polymer separation membrane is connected to the second polymer separation membrane, the residue stream of the second polymer separation membrane is connected to the third polymer separation membrane, and the permeate stream of the second polymer separation membrane is connected to the fourth polymer separation membrane (step 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 gas analyser, 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 pressure of the feed gas flow is adjusted according to a CH.sub.4 concentration of the second retentate.

Separation of a gas mixture comprising first and second gases may be improved using three stages of gas separation membrane modules that includes the additional techniques of cooling the feed gas stream that is fed to the feed stage and using a portion of the permeate stage retentate as a sweep gas on the permeate stage.

Separation of a gas mixture comprising first and second gases may be improved using four stages of gas separation membrane modules that includes the additional techniques of cooling the feed gas stream that is fed to the first (feed) stage and using a portion of the fourth (second permeate) stage retentate as a sweep gas on the permeate stage.

Systems and methods for retrieving equipment from a wellbore of a subterranean well include an overshot housing having a central axis. The overshot housing is a tubular shaped member with a housing bore. An internal sleeve is located within the overshot housing. The internal sleeve is a tubular shaped member with a sleeve bore. The internal sleeve is axially moveable within the overshot housing. A catching net is located radially outward of the internal sleeve, within the overshot housing. The catching net moveable between a contracted position and an extended position. The catching net has a shorter axial length and a wider radial width in the contracted position than in the extended position. An anchoring assembly is located at a downhole end of the catching net. The anchoring assembly is actuable to releasably secure the downhole end of the catching net to the equipment.

A process for recovering a noncondensable gas from a gaseous mixture, the method comprising the steps of: supplying a gaseous mixture comprising a noncondensable component; supplying a sweep gas comprising a condensable component; introducing the gaseous mixture and the sweep gas to a swept membrane stage to obtain a retentate stream and a mixed permeate stream, the mixed permeate stream comprising at least a portion of the condensable component and at least a portion of the noncondensable component; introducing the mixed permeate stream to a vapor-liquid separator and subjecting the mixed permeate stream to thermodynamic conditions sufficient to condense most of the condensable component into a liquid, and obtain a raw noncondensable component stream, wherein the raw noncondensable component stream is enriched in the noncondensable component; and introducing the raw noncondensable component to a concentration unit to obtain a noncondensable component product stream enriched in the noncondensable component.

A method of transporting hydrogen and natural gas by means of a natural gas conduit system is proposed, especially by means of an existing natural gas conduit system. According to the invention, the hydrogen is recovered only downstream of one or preferably multiple natural gas consumers. This resulted in a stepwise increase in the hydrogen content in the natural gas-hydrogen mixture transported, and the subsequent recovery of the pure hydrogen can be affected more easily and efficiently.

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 process for converting post-explosion gases of an inhabitable level, low-oxygen ambient environment to a breathable mixture for human consumption comprises receiving a flow of post-explosion gas with oxygen, carbon dioxide, carbon monoxide, nitrogen, and methane. The oxygen, carbon monoxide, and carbon dioxide are removed from the from the flow of post-explosion gas to create both a mixture including oxygen, carbon monoxide, and carbon dioxide; and a residual stream including nitrogen and methane. The oxygen is removed from the mixture of oxygen, carbon monoxide, and carbon dioxide, and concentrated in a primary oxygen storage canister. The nitrogen is removed from the residual stream and stored in a nitrogen storage canister separate from the oxygen storage canister. The methane is vented back to the inhabitable level, low-oxygen ambient environment. The stored oxygen and nitrogen are metered through a breathing mask at a habitable level of 19-21% oxygen to a user.