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.

The invention relates to a process for purifying synthesis gas, comprising at least one stage for separating the crude synthesis gas to be treated into at least two effluents, namely a first part and a complementary part, in which the said first part is subjected to a carbon monoxide conversion stage with steam and the said complementary part is subjected to a COS and HCN catalytic hydrolysis stage, the two gas flows, namely the first part and complementary part, are then each treated separately in two stages intended to remove acid gases such as CO.sub.2 and H.sub.2S, by washing with aqueous solutions of specific amines, before a recombination stage of the two treated effluents.

A gas stream comprising LPG and naphtha hydrocarbons is absorbed with a sponge absorbent to recover LPG and naphtha hydrocarbons. The gas stream may comprise stripper off gas and/or PSA tail gas. An absorbent stream may be a stripped stream. The stripper off gas stream and the stripped stream may be obtained from a stripper that is downstream of a hydroprocessing unit.

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 process for producing syngas that uses the syngas product from an oxygen-fired reformer to provide all necessary heating duties, which eliminates the need for a fired heater. Without the flue gas stream leaving a fired heater, all of the carbon dioxide produced by the reforming process is concentrated in the high-pressure syngas stream, allowing essentially complete carbon dioxide capture.

A process for producing syngas that uses the syngas product from a partial oxidation reactor to provide all necessary heating duties, which eliminates the need for a fired heater. Soot is removed from the syngas using a dry filter to avoid a wet scrubber quenching the syngas stream and wasting the high-quality heat. Without the flue gas stream leaving a fired heater, all of the carbon dioxide produced by the reforming process is concentrated in the high-pressure syngas stream, allowing essentially complete carbon dioxide capture.

A three-product PSA system which produces three product streams from a feed gas mixture comprising a light key component, at least one heavy key component, and at least one intermediate key component is described. The three-product PSA system produces a high pressure product stream enriched in the light key component, a low pressure tail gas stream enriched in the at least one heavy key component, and an intermediate pressure vent gas stream enriched in the at least one intermediate key component.

The present invention relates to a process for producing hydrogen and for separating carbon dioxide from synthesis gas using a physical absorption medium. The process comprises the steps where the synthesis gas and the absorption medium are cooled; carbon dioxide is removed from the cooled synthesis gas via the cooled absorption medium in a physical absorption step at elevated pressure; laden absorption medium is treated in a plurality of flash stages, wherein co-absorbed carbon monoxide, hydrogen and carbon dioxide are separately removed from the laden absorption medium; hydrogen is separated from synthesis gas freed of carbon dioxide in a physical separation step, wherein hydrogen as product gas and an offgas comprising hydrogen, carbon monoxide and carbon dioxide are obtained; product gas hydrogen and carbon dioxide are discharged from the process. The invention further relates to a plant for performing the process.

Hydrogen generation assemblies and methods of generating hydrogen are disclosed. In some embodiments, the method may include receiving a feed stream in a fuel processing assembly of the hydrogen generation assembly; and generating a product hydrogen stream in the fuel processing assembly from the received feed stream. Generating a product hydrogen stream may, in some embodiments, include generating an output stream in a hydrogen generating region from the received feed stream, and generating the product hydrogen stream in a purification region from the output stream. The method may additionally include receiving the generated product hydrogen stream in a buffer tank of the hydrogen generation assembly; and detecting pressure in the buffer tank via a tank sensor assembly. The method may further include stopping generation of the product hydrogen stream in the fuel processing assembly when the detected pressure in the buffer tank is above a predetermined maximum pressure.

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.