A process and an apparatus are disclosed for separation of a hydrocarbon gas stream containing methane and heavier hydrocarbons and significant quantities of nitrogen and carbon dioxide. The gas stream is cooled and expanded, then fractionated in a first distillation column into a first overhead vapor and a hydrocarbon liquid stream containing the majority of the carbon dioxide. The hydrocarbon liquid stream is fractionated into a hydrocarbon vapor stream and a less volatile fraction comprised of heavier hydrocarbons.

The first overhead vapor is cooled, expanded, and separated into vapor and liquid streams. Both streams are cooled and expanded before feeding a second distillation column that produces a second overhead vapor that is predominantly nitrogen and a bottom liquid that is predominantly methane. The bottom liquid is vaporized and combined with the hydrocarbon vapor stream to form a volatile residue gas fraction containing the majority of the methane.

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.

The present invention relates to the extraction of gasoline from a gas G, with (a) a step of extracting gasoline from the gas to be treated comprising methanol GM obtained from step (d), (b) a step of separating said fluid GL1 partially condensed in step (a), producing a first aqueous liquid phase Al , a first liquid phase H1 of hydrocarbon(s) a gaseous phase G1 obtained from the gas G; (c) a step of contacting a portion of the gas G to be treated with said first aqueous liquid phase A1, producing a second aqueous liquid phase A2, a gaseous phase of gas to be treated comprising methanol GM; (d) a step of mixing said gaseous phase of gas to be treated comprising methanol GM with the remainder of the gas G to be treated, producing a gas to be treated comprising methanol GM, (e) a step of stabilizing said first liquid phase H1 of hydrocarbon(s).

In a process for separating a mixture containing carbon monoxide, hydrogen and carbon dioxide, the mixture cooled in a heat exchanger is contacted by a stream of liquid methanol at a temperature below 40 C. to produce carbon dioxide enriched methanol and a carbon dioxide depleted gas relative to the cooled mixture, the carbon dioxide depleted gas is cooled in the heat exchanger and is sent to a separation unit to produce a carbon monoxide enriched stream and a hydrogen enriched stream and the streams enriched in carbon monoxide and hydrogen are heated in the heat exchanger by exchanging heat with the mixture.

A process for removing a foulant from a gas stream. The gas stream is cooled in a series of heat exchangers, causing a portion of the foulant to desublimate and become entrained in a cryogenic liquid. This foulant slurry stream is pressurized, cooled, and separated into a pressurized foulant solid stream and the cryogenic liquid stream. The pressurized foulant solid stream is melted to produce a liquid foulant stream. Heat exchange processes, both internal and external, are provided that close the heat balance of the process. In this manner, the foulant is removed from the gas stream.

Implementations described and claimed herein provide systems and methods for processing liquefied natural gas (LNG). In one implementation, a feed gas is received and partially condensed into a two-phase stream by expanding the feed gas. A liquid containing fouling components is removed from the two-phase stream. A vapor generated from the two-phase stream is compressed into a compressed feed gas. The compressed feed gas is directed into a feed chiller heat exchanger. The compressed feed gas is free of the fouling components.

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.

A method for removing heavy hydrocarbons from a feed gas by: feeding, into an absorber, a top reflux stream and a second reflux stream below the top reflux stream, wherein the absorber produces an absorber bottom product stream and an absorber overhead product stream; depressurizing and feeding the absorber bottom product stream to a stripper to produce a stripper bottom product stream and a stripper overhead product stream; cooling and feeding a portion of the absorber overhead product stream back to the absorber as the top reflux stream; and pressurizing and feeding the stripper overhead product stream back to the absorber as the second reflux stream. Systems for carrying out the method are also provided.

Implementations described and claimed herein provide systems and methods for processing liquefied natural gas (LNG). In one implementation, a solvent is injected into a feed of natural gas at a solvent injection point. A mixed feed is produced from a dispersal of the solvent into the feed of natural gas. The mixed feed contains heavy components. A chilled feed is produced by chilling the mixed feed. The chilled feed includes a vapor and a condensed liquid. The condensed liquid contains a fouling portion of the heavy components condensed by the solvent during chilling. The liquid containing the fouling portion of the heavy components is separated from the vapor. The vapor is directed into a feed chiller heat exchanger following separation of the liquid containing the fouling portion of the heavy components from the vapor, such that the vapor being directed into feed chiller heat exchanger is free of freezing components.

Embodiments provide a method for preventing shutdowns in LNG facilities by removing heavy hydrocarbons from the inlet gas supply. According to an embodiment, there is provided an LNG facility treating pipeline quality natural gas that is contaminated with lubrication oil and low concentrations of heavy hydrocarbons. Due to contamination, the behavior of the pipeline quality natural gas is not properly predicted by thermodynamic modeling. In an embodiment, heavy hydrocarbons are removed by a drain system in a heat exchanger. In an embodiment, heavy hydrocarbons are removed by a treatment bed.