Process and device for producing nitrogen-purified liquid methane from a feed gas stream containing at least 98 mol % of methane and between 0.1 and 2 mol % of nitrogen, in which the feed gas stream is cooled to a temperature of between 110 K and 200 K in a first heat exchanger in countercurrent with a stream of nitrogen vapour to produce a cooled stream, a bath of liquid nitrogen is in heat exchange with the cooled stream via a second heat exchanger through which the cooled stream passes, the liquid nitrogen bath producing nitrogen vapour supplied to the first heat exchanger to produce the cooled stream, the cooled stream leaving the second heat exchanger is introduced into a distillation column with a view to its distillation, and a liquid containing at least 99.5 mol % of methane is withdrawn from the bottom of the distillation column as the final product.

Example gas recovery systems include a source gas conditioning assembly configured to condition and compress the inlet source gas to provide a conditioned source gas, a first membrane assembly configured to separate the conditioned source gas into a hydrocarbon enriched stream and a recovery stream, a second membrane assembly fluidly coupled to the hydrocarbon enriched stream, and configured to separate the hydrocarbon enriched stream into a hydrocarbon product stream and a recycle stream, a carbon dioxide (CO.sub.2) plant assembly fluidly coupled to the recovery stream configured to provide a carbon dioxide product stream and an enriched recycle stream, a standalone membrane assembly configured to separate the enriched recycle stream into a hydrocarbon enriched recycle stream and an effluent stream, and wherein the source gas conditioning assembly is fluidly coupled to the recycle stream and the hydrocarbon enriched recycle stream.

Example gas recovery systems include a source gas conditioning assembly configured to condition and compress the inlet source gas to provide a conditioned source gas, a first membrane assembly configured to separate the conditioned source gas into a hydrocarbon enriched stream and a recovery stream, a second membrane assembly fluidly coupled to the hydrocarbon enriched stream, and configured to separate the hydrocarbon enriched stream into a hydrocarbon product stream and a recycle stream, a carbon dioxide (CO.sub.2) plant assembly fluidly coupled to the recovery stream configured to provide a carbon dioxide product stream and an enriched recycle stream, a standalone membrane assembly configured to separate the enriched recycle stream into a hydrocarbon enriched recycle stream and an effluent stream, and wherein the source gas conditioning assembly is fluidly coupled to the recycle stream and the hydrocarbon enriched recycle stream.

Disclosed is a device for refrigerating or liquefying a fluid such as natural gas or hydrogen, comprising a fluid circuit that is to be cooled and has an upstream end for connection to a source of gaseous fluid as well as a downstream end for connection to a member for collecting the cooled or liquefied fluid, the device comprising a heat exchanger assembly in heat exchange with the fluid circuit to be cooled, the device comprising a refrigerator in heat exchange with at least a portion of the exchanger assembly, the refrigerator being of the type that has a cycle for refrigerating a cycle gas containing at least one of: helium, hydrogen, nitrogen or neon; said refrigerator comprising in series in a cycle circuit: a mechanism for compressing the cycle gas, at least one member for cooling the cycle gas, a mechanism for expanding the cycle gas, and at least one member for reheating the expanded cycle gas, wherein the compression mechanism comprises a plurality of compression stages in series composed of a centrifugal compressor assembly, the compression stages being mounted on a set of shafts that are rotationally driven by a motor assembly, the at least one member for cooling the cycle gas comprising at least one heat exchanger at the outlet of at least one compression stage in heat exchange with the cycle circuit, said heat exchanger being cooled by a heat transfer fluid, characterized in that the compression mechanism comprises at least two compression stages that are arranged successively in series and do not include any member for cooling the cycle gas such as a heat exchanger therebetween.

The present disclosure relates to a carbon dioxide capture apparatus and process combined with biogas upgrading, and there is provided the carbon dioxide capture apparatus combined with biogas upgrading for simultaneously obtaining high purity methane and carbon dioxide, and improving separation efficiency without an additional process by making use of gas streams after a liquefaction process, and recovering cold heat in the process.

Example gas recovery systems include a source gas conditioning assembly configured to condition and compress the inlet source gas to provide a conditioned source gas, a first membrane assembly configured to separate the conditioned source gas into a hydrocarbon enriched stream and a recovery stream, a second membrane assembly fluidly coupled to the hydrocarbon enriched stream, and configured to separate the hydrocarbon enriched stream into a hydrocarbon product stream and a recycle stream, a carbon dioxide (CO.sub.2) plant assembly fluidly coupled to the recovery stream configured to provide a carbon dioxide product stream and an enriched recycle stream, a standalone membrane assembly configured to separate the enriched recycle stream into a hydrocarbon enriched recycle stream and an effluent stream, and wherein the source gas conditioning assembly is fluidly coupled to the recycle stream and the hydrocarbon enriched recycle stream.

Example gas recovery systems include a source gas conditioning assembly configured to condition and compress the inlet source gas to provide a conditioned source gas, a first membrane assembly configured to separate the conditioned source gas into a hydrocarbon enriched stream and a recovery stream, a second membrane assembly fluidly coupled to the hydrocarbon enriched stream, and configured to separate the hydrocarbon enriched stream into a hydrocarbon product stream and a recycle stream, a carbon dioxide (CO.sub.2) plant assembly fluidly coupled to the recovery stream configured to provide a carbon dioxide product stream and an enriched recycle stream, a standalone membrane assembly configured to separate the enriched recycle stream into a hydrocarbon enriched recycle stream and an effluent stream, and wherein the source gas conditioning assembly is fluidly coupled to the recycle stream and the hydrocarbon enriched recycle stream.