The invention relates to a process for cryogenic fractionation of air using an air fractionation plant comprising a rectification column system comprising a high-pressure column operated at a pressure level of 9 to 14.5 bar, a low-pressure column operated at a pressure level of 2 to 5 bar, and an argon column. It is envisaged that a recirculating stream is formed using the second tops gas or a portion thereof, which is heated, compressed, cooled again, and after partial or complete liquefaction or in the unliquefied state is introduced partially or completely, or in fractions, into the first rectification column and/or into the second rectification column. The present invention also relates to a corresponding system.

A system and method for flexible production of argon from a cryogenic air separation unit is provided. The cryogenic air separation unit is capable of operating in a ‘no-argon’ or ‘low-argon’ mode when argon demand is low or non-existent and then switching to operating in a ‘high-argon’ mode when argon is needed. The recovery of the argon products from the air separation unit is adjusted by varying the percentages of dirty shelf nitrogen and clean shelf nitrogen in the reflux stream directed to the lower pressure column. The cryogenic air separation unit and associated method also provides an efficient argon production/rejection process that minimizes the power consumption when the cryogenic air separation unit is operating in a ‘no-argon’ or ‘low-argon’ mode yet maintains the capability to produce higher volumes of argon products at full design capacity to meet argon product demands.

A system and method for flexible production of argon from a cryogenic air separation unit is provided. The cryogenic air separation unit is capable of operating in a ‘no-argon’ or ‘low-argon’ mode when argon demand is low or non-existent and then switching to operating in a ‘high-argon’ mode when argon is needed. The recovery of the argon products from the air separation unit is adjusted by varying the percentages of dirty shelf nitrogen and clean shelf nitrogen in the reflux stream directed to the lower pressure column. The cryogenic air separation unit and associated method also provides an efficient argon production/rejection process that minimizes the power consumption when the cryogenic air separation unit is operating in a ‘no-argon’ or ‘low-argon’ mode yet maintains the capability to produce higher volumes of argon products at full design capacity to meet argon product demands.

A heat exchanger assembly and a method for assembling the heat exchanger assembly is provided. The heat exchanger assembly comprises a first heat exchanger and a second heat exchanger, and a subcooler; a first heat exchanger cold box, for accommodating the first heat exchanger and heat exchange fluid pipelines, with a first opening being disposed in a side of the first heat exchanger cold box, and a first group of pipelines extending through the first opening; a second heat exchanger cold box, for accommodating the second heat exchanger and heat exchange fluid pipelines, with a second opening being disposed in a side of the second heat exchanger cold box, and a second group of pipelines extending through the second opening; a subcooler cold box, for accommodating the subcooler and heat exchange fluid pipelines, with a third opening and a fourth opening being disposed in a side of the subcooler cold box, and a third group of pipelines and a fourth group of pipelines extending through the third opening and the fourth opening respectively, wherein the first group of pipelines and the third group of pipelines are connected and encapsulated in a first thermally isolating casing, and the second group of pipelines and the fourth group of pipelines are connected and encapsulated in a second thermally isolating casing.

A method for flexible production of argon from a cryogenic air separation unit is provided. The disclosed cryogenic air separation unit is capable of operating in a ‘no-argon’ or ‘low-argon’ mode when argon demand is low or non-existent and then switching to operating in a ‘high-argon’ mode when argon is needed. The recovery of the argon products from the air separation unit is adjusted by varying the percentages of dirty shelf nitrogen and clean shelf nitrogen in the reflux stream directed to the lower pressure column. The cryogenic air separation unit and associated method also provides an efficient argon production/rejection process that minimizes the power consumption when the cryogenic air separation unit is operating in a ‘no-argon’ or ‘low-argon’ mode yet maintains the capability to produce higher volumes of argon products at full design capacity to meet argon product demands.

A process for producing liquid oxygen, including an offshore platform the system including cooling a high-pressure nitrogen gas stream in a main heat exchanger, thereby producing a cooled high-pressure nitrogen gas stream, expanding the cooled high-pressure nitrogen gas stream in a turbo-expander, thereby producing a cold low-pressure nitrogen gas stream, warming the cold low-pressure nitrogen gas stream by indirect heat exchange with a high-pressure gaseous oxygen stream, thereby producing a liquefied oxygen stream and a warm low-pressure nitrogen gas stream, wherein, at least a portion of the warm low-pressure nitrogen gas stream is vented to the atmosphere.

A system and method for argon production in an air separation plant facility or enclave having multiple cryogenic air separation units is provided. The present system and method include a centralized argon refining system disposed within one of the cryogenic air separation units and which is configured to include an argon superstaged or ultra-superstaged column arrangement having one or more argon columns and an argon condenser. Crude argon streams from one or more of the other cryogenic air separation units are directed to the argon superstaged or ultra-superstaged column arrangement of the centralized argon refining process.

A distillation column system and a plant are for production of oxygen by cryogenic fractionation of air. The distillation column system has a high-pressure column and a low-pressure column, a main condenser, and an argon column with an argon column top condenser. The low-pressure column comprises an upper mass transfer region, a lower mass transfer region and a middle mass transfer region. The argon column top condenser is arranged within the low-pressure column between the upper and middle mass transfer regions and is configured as a forced-flow evaporator.

Disclosed in the present invention are a heat exchanger assembly and a method for assembling the heat exchanger assembly. The heat exchanger assembly comprises a first heat exchanger and a second heat exchanger, and a subcooler; a first heat exchanger cold box, for accommodating the first heat exchanger and heat exchange fluid pipelines, with a first opening being disposed in a side of the first heat exchanger cold box, and a first group of pipelines extending through the first opening; a second heat exchanger cold box, for accommodating the second heat exchanger and heat exchange fluid pipelines, with a second opening being disposed in a side of the second heat exchanger cold box, and a second group of pipelines extending through the second opening; a subcooler cold box, for accommodating the subcooler and heat exchange fluid pipelines, with a third opening and a fourth opening being disposed in a side of the subcooler cold box, and a third group of pipelines and a fourth group of pipelines extending through the third opening and the fourth opening respectively, wherein the first group of pipelines and the third group of pipelines are connected and encapsulated in a first thermally isolating casing, and the second group of pipelines and the fourth group of pipelines are connected and encapsulated in a second thermally isolating casing.

A process comprises a first set of distillation columns and a second set of distillation columns, a low-pressure column of the first set being connected to a column operating at higher pressure of the second set by means of a gas arriving from the top of the column operating at a higher pressure and/or by means of a fluid arriving from the low-pressure column.