Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

This method comprises passing a residual stream into a flash drum to form a gaseous overhead flow and liquid bottom flow, and feeding the bottom flow into a distillation column,

It comprises cooling the overhead flow in a heat exchanger to form a cooled overhead flow.

It comprises the extraction of a gaseous overhead stream at the head of the distillation column, and the formation of at least one effluent stream from the overhead stream and/or from the top stream.

The separation of the cooled overhead flow flow comprises passing the cooled overhead flow into an absorber, and injecting a methane-rich stream into the absorber to place the cooled overhead flow in contact with the methane-rich stream.

Gas processing plants and methods are contemplated in CO.sub.2 is effectively removed to very low levels from a feed gas to an NRU unit by adding a physical solvent unit that uses waste nitrogen produced by the NRU as stripping gas to produce an ultra-lean solvent, which is then used to treat the feed gas to the NRU unit. Most preferably, the physical solvent unit includes a flash unit and stripper column to produce the ultra-lean solvent.

A cryogenic air separation unit that provides flexibility in the production of liquid products is disclosed. The present cryogenic air separation unit and associated operating methods involves the use of a dual nozzle arrangement for the main heat exchanger that allows a turbine air stream draw from the main heat exchanger at different temperatures to provide refrigeration to the cryogenic air separation unit which, in turn, enables different production modes for the various liquid products.

In a process of the separation of a mixture of carbon monoxide, hydrogen and methane, the mixture is sent to a scrubbing column, a bottom liquid withdrawn at the bottom of the scrubbing column is depleted in hydrogen with respect to the mixture and is sent to a stripping column, a bottom liquid from the stripping column is sent to a separation column and a liquid enriched in methane withdrawn from the bottom of the separation column is vaporized in order to form a final product.

A method to recover and process hydrocarbons from a gas flare system to produce natural gas liquids (NGL), cold compressed natural gas (CCNG), compressed natural gas (CNG) and liquid natural gas (LNG). The method process provides the energy required to recover and process the hydrocarbon gas stream through compression and expansion of the various streams.

Methods and systems for processing natural gas to meet gas pipeline specifications and/or recovering natural gas liquids (NGL). The natural gas is cooled and distilled such that propane and heavier components are produced as a bottoms NGL product, and inerts, methane, ethane, and other lighter portions are produced as a fuel gas grade/quality residue gas product stream. The gas can optionally be treated to remove hydrogen-sulfide and/or carbon dioxide. The NGL product can be split into a marketable propane and butane liquefied petroleum gas (LPG) liquid product and a natural gas condensate product.

A system for conditioning a sour gas feed stream for a cryogenic distillation tower. A dehydration unit separates the sour gas feed stream into a first stream including water and a feed stream. A sequential cooling assembly is coupled to both the dehydration unit and the cryogenic distillation tower. The sequential cooling assembly includes: a first stage that separates the feed stream into a partially cooled feed stream and a second stream including acid gas; a second stage that cools the partially cooled feed stream into a cooled feed stream and a third stream including acid gas; and a cooled feed stream header coupled to a cryogenic distillation tower feed inlet. The first stage, the second stage, or both send at least one of the second and third streams to a bottom section of the cryogenic distillation tower.

An acid gas purification system is described herein that includes a primary membrane system with a CO.sub.2- and H.sub.2S-enriched permeate stream effluent and a hydrocarbon stream effluent; a first compression stage arranged to receive the CO.sub.2- and H.sub.2S-enriched permeate stream and produce a compressed stream; and a cryogenic separation system to receive the compressed stream, the cryogenic separation system including a cooler followed by a fractionator, wherein the fractionator produces a CO.sub.2- and H.sub.2S liquid stream and a hydrocarbon gas stream.

This disclosure relates to a means of separating a gaseous mixture into both a purified stream and reject stream that can each be used for individual purposes. The disclosure will generally be connected to a gas supply such as a wellhead or gas pipe or other source where the gas makes contact with a membrane filter. The gaseous mixture should either have sufficient intrinsic pressure to be optimally filtered by the membrane filter or have the pressure boosted. Means of increasing the pressure includes ejectors, vacuum pumps and where the gas composition allows compressors. The retentave may be discharged into a pipeline, road or rail carriage or be liquefied. The permeate may be combusted through a combustion device to generate electricity and heat. Alternatively, the permeate may be discharged into a pipeline, road or rail carriage or stored for further use. The advantages of this disclosure include reduced capital and operational cost and a reduction in unnecessary environmental emissions.