In a device for separating methane from a gas mixture containing methane, carbon dioxide and hydrogen sulfide, comprising a gas compressor, two or three membrane separation stages downstream of the compressor and a hydrogen sulfide adsorber, comprising a bed of activated carbon having catalytic activity for oxidizing hydrogen sulfide with oxygen, arranged upstream of the membrane separation stages, oxygen content and relative humidity can be adjusted for optimum adsorption capacity of the hydrogen sulfide adsorber by recycling permeate from the second membrane separation stage, which receives the retentate of the first membrane separation stage, to a point upstream of the hydrogen sulfide adsorber.

A device for separating a gas, such as air, into components, includes a plurality of modules, each module having one or more polymeric membranes capable of gas separation. A set of valves, pipes, and manifolds together arrange the modules in one of two possible configurations. In a first configuration, the modules are arranged in parallel. In a second configuration, the modules are divided into two groups which are arranged in series. The device can be switched from parallel to series, or from series to parallel, simply by changing the positions of a small number of valves, typically three valves. The device can therefore produce gas either of higher purity, or moderate purity, depending on the settings of the valves. The device also includes improved structures for connecting the modules to inlet and outlet manifolds, and also includes devices for temporarily isolating one or more modules from the system.

The CO.sub.2 separation system performs, when the internal combustion engine is operating and the vehicle is travelling, a first mode wherein exhaust gas generated by the internal combustion engine is introduced to a CO.sub.2 supply side of a first CO.sub.2 separation device via a first CO.sub.2 supply side introduction flow path, and air from outside the vehicle is introduced to a CO.sub.2 permeation side of the first CO.sub.2 separation device via a first CO.sub.2 permeation side introduction flow path using travelling wind, whereby CO.sub.2 in the exhaust gas selectively permeates from the CO.sub.2 supply side to the CO.sub.2 permeation side of the first CO.sub.2 separation device through a CO.sub.2 permeable membrane of the first CO.sub.2 separation device using a difference in CO.sub.2 partial pressure between the CO.sub.2 supply side and the CO.sub.2 permeation side of the first CO.sub.2 separation device as a driving force.

A method for capturing carbon dioxide from a carbon dioxide feed stream in which the carbon dioxide feed stream is dehydrated, cooled, and partially condensed. The partially condensed carbon dioxide stream is separated to form the carbon dioxide product stream. The carbon dioxide feed stream is produced by combusting a fuel stream with an oxygen-enriched gas stream with less than 92% purity.

A stream of raw biogas is feed to an upstream-most compression stage of a multi-stage compression unit to produce a feed gas for separation by a gas separation membrane-based purification unit into a methane-enriched product gas stream, one or more recycle gas streams, and one or more waste gas streams. The methane-enriched product gas stream is compressed by a downstream or downstream-most compression stage of the multi-stage compression unit to produce a stream of product compressed natural gas.

Facility for the treatment of a feed gas stream comprising at least methane and carbon dioxide, said facility comprising: an oil-lubricated or water-lubricated vane-type compressor making it possible to compress the feed gas stream, and a membrane separation unit capable of receiving the compressed gas stream and of separating the methane from the carbon dioxide.

Natural gas may be purified by removing C.sub.3+ hydrocarbons and CO.sub.2 in respective one or more separation units to yield conditioned gas lower in C.sub.3+ hydrocarbons and CO.sub.2 in comparison to the un-conditioned natural gas. Notably, the feed gas need not be subjected to joule-thomson expansion and molecular sieve dehydration performed by conventional processes. Rather, any water-rich reject stream from the separation unit(s) is dried downstream with a smaller compressor and smaller molecular sieve or gas separation membrane dehydration unit before it may be re-injected deep underground or deep under the sea bed.

At least some VOCs are removed from a feed gas in an adsorption unit comprising at least three adsorbers following a pressure cycle with a phase shift, wherein the feed gas comprises at least methane, carbon dioxide and volatile organic compounds (VOCs). The VOC depleted gas is fed to at least one membrane separation to produce a carbon dioxide-enriched permeate and a methane-enriched retentate. The flow of the feed gas stream is adjusted based upon one or both of a pressure or methane concentration of the gas stream entering the membrane separation unit and/or a pressure in the adsorption unit.

A gas separation apparatus includes a separation membrane module including at least one gas separation membrane element in a housing, a casing for blocking external air, and a heat source unit for adjusting a temperature of a heat medium with which the casing is filled. The casing holds greater than or equal to two separation membrane modules.

A device for separating a gas, such as air, into components, includes a plurality of modules, each module having one or more polymeric membranes capable of gas separation. A set of valves, pipes, and manifolds together arrange the modules in one of two possible configurations. In a first configuration, the modules are arranged in parallel. In a second configuration, the modules are divided into two groups which are arranged in series. The device can be switched from parallel to series, or from series to parallel, simply by changing the positions of a small number of valves, typically three valves. The device can therefore produce gas either of higher purity, or moderate purity, depending on the settings of the valves.