At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapor contact column (130). Absorbent containing impurity may be regenerated in a regeneration vessel 150 and returned to the column (130).

In a method for separating a synthesis gas containing carbon monoxide and hydrogen, a synthesis gas flow from a synthesis gas source is compressed in a compressor and separated into at least three gaseous products. If there is insufficient synthesis gas, at least three separation products are recycled in the compressor in order to separate said products.

In order to provide a hydrogen purification device in which a source gas is supplied, from which a purified gas flows out, that is easily manufacturable, and in which the pressure resistance of an hydrogen permeable membrane is high, the hydrogen purification device is configured to include a hydrogen permeable membrane allowing hydrogen to selectively permeate therethrough, two porous supports that sandwich and support the hydrogen permeable membrane from both surfaces thereof, and a casing having a space formed therein configured to accommodate reaction of the source gas and the hydrogen permeable membrane. The porous supports are contained inside the casing, an outermost edge of the hydrogen permeable membrane extends outward from the outer edges of the porous supports in at least one location, and a peripheral portion of the hydrogen permeable membrane in a vicinity of the outermost edge and the casing are airtightly sealed to each other.

In accordance with the present invention, disclosed herein is a method comprising the steps for separating syngas and methane from C2-C4 hydrocarbons. Also disclosed herein, are systems utilized to separate syngas and methane from C2-C4 hydrocarbons.

In accordance with the present invention, disclosed herein is a method comprising the steps for separating syngas and methane from C2-C4 hydrocarbons. Also disclosed herein, are systems utilized to separate syngas and methane from C2-C4 hydrocarbons.

A process for producing ammonia synthesis gas from a hydrocarbon-containing feedstock, with steps of primary reforming, secondary reforming with an oxidant stream, and further treatment of the synthesis gas including shift, removal of carbon dioxide and methanation, wherein the synthesis gas delivered by secondary reforming is subject to a medium-temperature shift (MTS) at a temperature between 200 and 350 C., and primary reforming is operated with a steam-to-carbon ratio lower than 2. A corresponding method for revamping an ammonia plant is disclosed, where an existing HTS reactor is modified to operate at medium temperature, or replaced with a new MTS reactor, and the steam-to-carbon ratio in the primary reformer is lowered to a value in the range 1-52, thus reducing inert steam in the flow rate trough the equipments of the front-end.

A system and method for cryogenic purification of a hydrogen, nitrogen, methane and argon containing feed stream to produce a methane free, hydrogen and nitrogen containing synthesis gas and a methane rich fuel gas, as well as to recover an argon product stream, excess hydrogen, and excess nitrogen is provided. The disclosed system and method are particularly useful as an integrated cryogenic purifier in an ammonia synthesis process in an ammonia plant. The excess nitrogen is a nitrogen stream substantially free of methane and hydrogen that can be used in other parts of the plant, recovered as a gaseous nitrogen product and/or liquefied to produce a liquid nitrogen product.

A process for separating two gaseous streams, including purifying a first gaseous stream in a first acid gas removal absorber, purifying in a first temperature swing adsorption unit, and then separating at a cryogenic temperature in a separation unit to produce a stream of fluid enriched in carbon monoxide and a stream of fluid enriched in hydrogen, sending a second gaseous stream containing at least carbon monoxide, hydrogen and at least one acid gas to a shift reaction unit, the shifted second stream is purified in a second acid gas removal absorber to remove carbon dioxide and the purified second stream is sent as a feed stream to a pressure swing adsorption unit to produce a hydrogen enriched stream, and sending at least part of the stream enriched in hydrogen from the separation unit as a feed stream to the pressure swing adsorption unit to produce the hydrogen-enriched stream.

Process for the synthesis of ammonia from a make-up gas containing hydrogen and nitrogen, said process comprising: generation of a synthesis gas (8) containing hydrogen and nitrogen in a molar ratio lower than 3, inside a front-end section (2); a first cryogenic purification, designed to remove nitrogen and raise said molar ratio; conversion of the synthesis gas into ammonia (13) inside a high-pressure synthesis loop (6), with extraction from said loop of a purge stream (14) containing hydrogen and inert gases; wherein at least a portion of said purge stream (14) undergoes a further purification in order to recover at least part of the hydrogen contained therein, obtaining at least one stream (15, 15a, 16, 18) containing recovered hydrogen which is recycled to the process.

In a method for producing a gaseous mixture of CO and H.sub.2, a first gas comprising at least 50% CO is compressed in a first compressor to form a first compressed gas cooled to a first temperature and mixes with a second gas comprising at least 50% hydrogen in order to form the gaseous mixture, at least one of the first and second gases originating from a cryogenic distillation separation unit in which a feed gas containing H.sub.2 and CO cools in a first heat exchanger and is separated in at least one distillation column and at least one part of the second gas heats in the separation unit to a third temperature lower than the first temperature and is then sent to mix with the first gas.