A system and method for improving the performance of an oxygen, nitrogen, and argon producing air separation unit configured to produce a gaseous nitrogen product stream is provided. By recycling the argon condenser boil-off vapor stream to the main air compression train, the argon recovery and oxygen recovery while maintaining the production level of a medium or high pressure gaseous nitrogen product stream. In addition, some operational cost savings in terms of lower power costs can also be realized compared to some prior art oxygen, nitrogen, and argon producing air separation units.

An apparatus for producing product nitrogen gas and product argon, comprising: a first rectification column into which raw air is introduced; a second rectification column from which product nitrogen gas is drawn; a third rectification column from which product argon gas is drawn; and a first condenser configured to perform heat exchange between a gas accumulated in a column top portion of the first rectification column, and a liquid accumulated in a column bottom portion of the second rectification column, wherein an intermediate portion gas containing nitrogen is drawn from an intermediate portion of the second rectification column and merged with a condenser gas drawn from the first condenser. The merged gases are expanded and cooled by means of an expansion turbine whereby the cold thereof is utilized.

A system and method for argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as a low-pressure tail gas of an ammonia production plant is provided. The disclosed system and method provides for a rectification system wherein an argon depleted gaseous stream and a methane rich liquid stream are produced and subsequently combined in whole or in part prior to vaporization. Nitrogen and argon containing streams may also be produced from the rectification system. An argon stripping column arrangement is also disclosed where residual argon is removed from the methane-rich fuel gas and recycled back to the feed stream.

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.

In a process for supplying oxygen and/or nitrogen and also argon to a geographic zone, the geographic zone comprising n units for air separation by cryogenic distillation, of which a first unit and n-1 second units produce oxygen and/or nitrogen but do not produce argon, the oxygen and/or nitrogen for at least certain clients come from at least one of the n-1 second, non-argon-producing units, and argon for these clients comes from the first unit, where the first unit operates by means of a column system comprising a double column composed of a higher pressure column operating at a first pressure and a lower pressure column, whose bottom is connected thermally to the top of the higher pressure column, operating at a second pressure, which is lower than the first pressure, and of an argon-producing column and a mixing column, wherein the mixing column is fed at the bottom with an auxiliary gas consisting of gaseous nitrogen from the first or the lower pressure column, and at the top with a liquid which is richer in oxygen than the auxiliary gas and is taken from the lower part of the low-pressure column, and impure oxygen constituting a production gas is withdrawn at the top of the mixing column, the argon-producing column is fed with an argon-enriched gas flow from the lower pressure column, and an argon-rich product is withdrawn from the argon-producing column.

In a process for the separation of a flow containing at least 97% mol of carbon monoxide containing at least one lighter compound and at least one heavier compound, the flow is separated in a column and a column, one of the columns being a denitrogenation column and the other a column for purification in argon, in order to form a flow very rich in carbon monoxide.

A process comprising: subjecting a process gas containing NOx to a stage for absorption of NOx in a suitable absorption means, obtaining nitric acid and a tail gas containing nitrogen, argon and residual NOx; subjecting said tail gas to a treatment which comprises at least one NOx removal stage, obtaining a conditioned tail gas; subjecting at least a portion of said conditioned tail gas to a separation treatment, obtaining a product stream containing argon and a product stream containing nitrogen.

A method for producing power and argon is provided by providing a residual gas stream, purifying the residual gas stream in a front-end purification unit to remove carbon dioxide, thereby forming a purified residual gas stream, and introducing the purified residual gas stream to a cold box, wherein the purified residual gas stream is cooled and expanded within the cold box to produce power and then fed to a distillation column system for separation therein, thereby forming an argon-enriched stream and optionally a nitrogen-enriched stream and/or an oxygen-enriched stream, wherein the residual gas stream is sourced from a retentate stream of a cold membrane having oxygen, nitrogen, carbon dioxide, and argon.

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 process comprising: subjecting a process gas containing NOx to a stage for absorption of NOx in a suitable absorption means, obtaining nitric acid and a tail gas containing nitrogen, argon and residual NOx; subjecting said tail gas to a treatment which comprises at least one NOx removal stage, obtaining a conditioned tail gas; subjecting at least a portion of said conditioned tail gas to a separation treatment, obtaining a product stream containing argon and a product stream containing nitrogen.