An apparatus for the distillation of air by cryogenic distillation is provided. The apparatus can include an enclosure; a first distillation column configured to operate at a first pressure; a second distillation column configured to operate at a second pressure that is lower than the first pressure, the second distillation column being placed above the first distillation column and forming therewith a double column; a subcooling heat exchanger configured to cool at least one liquid from the first distillation column upstream of the second distillation column and configured to warm a gaseous nitrogen stream from the second distillation column; and an argon column configured to separate an argon enriched stream from the second distillation column and configured to produce an argon rich stream. In certain embodiments, the first distillation column, the second distillation column, the argon column and the subcooling heat exchanger are disposed within the enclosure, and/or the subcooling heat exchanger is disposed directly underneath the first distillation column or the argon column.

A moderate pressure air separation unit and air separation cycle is disclosed that provides for up to about 96% recovery of argon and an overall nitrogen recovery of 98% or greater. The air separation is configured to produce a high purity oxygen enriched stream which is used as the refrigerant to condense the argon in the argon condenser, with the resulting vaporized oxygen stream used to regenerate the temperature swing adsorption prepurifier unit. Argon recovery is facilitated with the use of an argon superstaged column.

A system and a method for processing air prior to separating components of the air are disclosed. The system comprises an air cooler, one or more compression stages operated in series, and one or more intercoolers installed between two adjacent compression stages. A blowdown storage tank is configured to collect water blowdown from one or more intercoolers and provide cooling medium to the air cooler. Atmospheric air is first sprayed by the water blowdown in the air cooler to form a cooled air stream. The cooled air stream is subsequently compressed in the one or more compression stages and cooled by the intercoolers between two adjacent compression stages. The water blowdown from one or more of the intercoolers is collected and recycled as the cooling medium to cool the atmospheric air before it enters the first compression stage.

An apparatus for the distillation of air by cryogenic distillation is provided. The apparatus can include an enclosure; a first distillation column configured to operate at a first pressure; a second distillation column configured to operate at a second pressure that is lower than the first pressure, the second distillation column being placed above the first distillation column and forming therewith a double column; a subcooling heat exchanger configured to cool at least one liquid from the first distillation column upstream of the second distillation column and configured to warm a gaseous nitrogen stream from the second distillation column; and an argon column configured to separate an argon enriched stream from the second distillation column and configured to produce an argon rich stream. In certain embodiments, the first distillation column, the second distillation column, the argon column and the subcooling heat exchanger are disposed within the enclosure, and/or the subcooling heat exchanger is disposed directly underneath the first distillation column or the argon column.

An air separation unit and associated method for separating air by cryogenic distillation using a distillation column system including a higher pressure column, a lower pressure column, an intermediate pressure kettle column, and an argon column arrangement is provided. The disclosed air separation unit and method is particularly suited for production of an argon product as well as several nitrogen products wherein a portion of the nitrogen overhead intermediate pressure kettle column is taken as an intermediate or elevated pressure nitrogen product. The present air separation unit and associated method employs a once-through kettle column reboiler, a once-through kettle column condenser while the argon condenser condenses an argon-rich vapor stream against a pumped oxygen stream from the bottom of the lower pressure column.

A process for recovering at least one fluid (e.g. argon gas and/or nitrogen gas, etc.) from a feed gas (e.g. air) can provide an improved recovery of argon and/or nitrogen as well as an improvement in operational efficiency. Some embodiments can be adapted so that at least a portion of a mixed nitrogen-oxygen fluid is at least partially vaporized and fed to a low pressure column.

A system and method for producing two or more nitrogen product streams and a crude argon stream from a nitrogen and argon producing air separation unit is provided. The disclosed embodiments of the cryogenic-based nitrogen and argon producing air separation units and associated air separation cycles include the means for directing a first portion of a boil-off stream from an argon condenser of the air separation unit to a waste expansion refrigeration circuit and concurrently recycling a second portion of the boil-off stream from the argon condenser to the main air compression system of the air separation unit to be mixed or blended with the incoming feed air. Optionally, a third portion of the boil-off stream from the argon condenser may be further compressed in a cold compressor and returned to the lower pressure column.

A method for separating air by cryogenic distillation is provided, in which, at least one portion of the first oxygen-enriched liquid is sent from a first column to a first vaporizer-condenser where it is partially vaporized in the form of a film at a pressure higher than the second pressure forming a second oxygen-enriched liquid constituting at least 30% of the oxygen-enriched liquid sent to the first vaporizer-condenser and a third oxygen-enriched gas, an argon-enriched fluid is sent from a second column to a third column and the fluid is separated in the column forming an argon-rich flow at the top of the column and an oxygen-rich flow at the bottom of the column and the third oxygen-enriched gas is expanded in a turbine with production of work.

A moderate pressure air separation unit and air separation cycle is disclosed that provides for up to about 96% recovery of argon and an overall nitrogen recovery of 98% or greater. The air separation is configured to produce a high purity oxygen enriched stream which is used as the refrigerant to condense the argon in the argon condenser, with the resulting vaporized oxygen stream used to regenerate the temperature swing adsorption prepurifier unit. Argon recovery is facilitated with the use of an argon superstaged column.

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.