A system and method for argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as tail gas of an ammonia production plant is provided. The disclosed system and method provides for nitrogen-argon rectification and the methane rejection within a column system comprised of at least one distillation column. Nitrogen and argon are further separated and to produce liquid products. An argon stripping column arrangement is disclosed where residual argon is further removed from the methane-rich fuel gas and recycled back to the feed stream.

An argon reflux condensation system and method in which a plurality of once-through condensers are connected to an argon column of an air separation plant to condense argon-rich vapor streams for production of reflux to the argon column. Condensation of the argon-rich vapor streams is brought about through indirect heat exchange with crude liquid oxygen streams that partially vaporize and are introduced into a lower pressure column of the plant for further refinement. The flow rate of the crude liquid oxygen streams are sensed and controlled at locations in the air separation plant where the crude liquid oxygen is in a liquid state and in proportion to the size of the once-through heat exchangers. Prior to flowing into the once-through condensers, the partially vaporized crude oxygen stream enters a phase separator which separates the crude oxygen vapor from the crude liquid oxygen. The separated crude oxygen vapor bypasses the once-through condensers and is mixed with the vaporized oxygen stream that exits the one-through condensers. Feed stream flow rate to the argon column is controlled in response to air flow rate to the plant and product flow rate is controlled in response to the feed stream flow rate to the argon column.

An argon reflux condensation system and method in which a plurality of once-through heat exchangers are connected to an argon column of an air separation plant to condense argon-rich vapor streams for production of reflux to the argon column. Condensation of the argon-rich vapor streams is brought about through indirect heat exchange with crude liquid oxygen streams that partially vaporize and are introduced into a lower pressure column of the plant for further refinement. The flow rate of the crude liquid oxygen streams are sensed and controlled at locations in the plant where the crude liquid oxygen is in a liquid state and in proportion to the size of the once-through heat exchangers. Feed stream flow rate to the argon column is controlled in response to air flow rate to the plant and product flow rate is controlled in response to the feed stream flow rate to the argon column.

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.

An argon reflux condensation system and method in which a plurality of once-through condensers are connected to an argon column of an air separation plant to condense argon-rich vapor streams for production of reflux to the argon column. Condensation of the argon-rich vapor streams is brought about through indirect heat exchange with crude liquid oxygen streams that partially vaporize and are introduced into a lower pressure column of the plant for further refinement. The flow rate of the crude liquid oxygen streams are sensed and controlled at locations in the air separation plant where the crude liquid oxygen is in a liquid state and in proportion to the size of the once-through heat exchangers. Prior to flowing into the once-through condensers, the partially vaporized crude oxygen stream enters a phase separator which separates the crude oxygen vapor from the crude liquid oxygen. The separated crude oxygen vapor bypasses the once-through condensers and is mixed with the vaporized oxygen stream that exits the one-through condensers. Feed stream flow rate to the argon column is controlled in response to air flow rate to the plant and product flow rate is controlled in response to the feed stream flow rate to the argon column.

A system and method for argon and nitrogen extraction and liquefaction from a low-pressure tail gas of an ammonia production plant is provided. The preferred tail gas of the ammonia production plant comprises methane, nitrogen, argon, and hydrogen. The disclosed system and method provides for the methane rejection via rectification and hydrogen rejection by way of a side stripper column or phase separator. The resulting nitrogen and argon containing stream is separated and liquefied in a double column distillation system.

A system and method for argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as tail gas of an ammonia production plant is provided. The disclosed system and method provides for nitrogen-argon rectification and the methane rejection within a column system comprised of at least one distillation column. Nitrogen and argon are further separated and to produce liquid products. An argon stripping column arrangement is disclosed where residual argon is further removed from the methane-rich fuel gas and recycled back to the feed stream.

An argon reflux condensation system and method in which a plurality of once-through heat exchangers are connected to an argon column of an air separation plant to condense argon-rich vapor streams for production of reflux to the argon column. Condensation of the argon-rich vapor streams is brought about through indirect heat exchange with crude liquid oxygen streams that partially vaporize and are introduced into a lower pressure column of the plant for further refinement. The flow rate of the crude liquid oxygen streams are sensed and controlled at locations in the plant where the crude liquid oxygen is in a liquid state and in proportion to the size of the once-through heat exchangers. Feed stream flow rate to the argon column is controlled in response to air flow rate to the plant and product flow rate is controlled in response to the feed stream flow rate to the argon column.

An ammonia plant is disclosed, where ammonia purge gas (20), is sent to a cryogenic recovery unit, said recovery unit comprising means of cooling (102, 202, 302, 402, 502) and a high-pressure phase separator (103, 203, 303, 403, 503) operating at loop pressure; inside said unit the purge gas (20) is cooled to a cryogenic temperature, and a partial liquefaction of methane and argon is achieved; the high-pressure phase separator separates the cooled stream into a gaseous stream and a bottom liquid; the gaseous stream is reheated in a passage of a heat exchanger; the unit is then capable to export a gaseous stream (123, 223, 323, 423, 523) containing nitrogen and hydrogen at loop pressure, that can be reintroduced at the suction side of the circulator (4) of the loop.

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.