Enhancements to a dual column, nitrogen producing cryogenic air separation unit are provided. Such enhancements include an improved air separation cycle that uses three condenser-reboilers and recycles a portion of the vapor from one or more of the condenser-reboilers to the incoming feed stream and or the compressed purified air streams to yield improvements in the performance of such dual column, nitrogen producing cryogenic air separation units in terms of overall nitrogen recovery as well as power consumption.

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.

Enhancements to a dual column, nitrogen producing cryogenic air separation unit are provided. Such enhancements include an improved air separation cycle that uses multiple condenser-reboilers and recycles a portion of the vapor from one or more of the condenser-reboilers to the incoming feed stream and or the compressed purified air streams to yield improvements in such dual column, nitrogen producing cryogenic air separation units. The multiple condenser-reboilers preferably include an integrated condenser-reboiler arrangement comprising a heat exchanger having a set of nitrogen condensing passages, a first set and second set of boiling passages, and a phase separator.

A method for obtaining one or more air products, wherein an air separation system having a rectification column system is used, in which pressurized air is processed in an adjustable total air volume, wherein the total air volume is set to a first value during a first operating period and set to a second value that is different from the first value during a second operating period, and wherein the setting of the total air volume is changed from the first value to the second value in a third operating period from a first time to a second time. The second operating period is after the first operating period, the third operating period is between the first operating period and the second operating period. In the third operating period, a setting of a volume of a fluid, is changed from a third time up to a fourth time.

In a method for separating air by cryogenic distillation using a column system consisting of a higher pressure column operating at a first pressure and a lower pressure column operating at a second pressure, a first air flow constituting between 75% and 98% of the air sent to the column system compressed to a third pressure above the first pressure, is sent to the higher pressure column, a second air flow constituting between 5% and 25% of the air sent to the column system is compressed to a fourth pressure above the second pressure but lower than the third pressure, is sent to the lower pressure column, a third column separates an argon-enriched flow and the air sent to the lower pressure column constitutes between 10% and 25% of the total air sent to the column system.

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.

Enhancements to the distillation column system and cycles for an argon and nitrogen producing cryogenic air separation unit are provided. The enhancements include systems and methods for: (i) recovery of xenon and krypton; (ii) production of oxygen product substantially free of hydrocarbons; and (iii) improvement in the design and performance of the super-stage argon column. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

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 include utilization of a compression system, primary heat exchanger unit, plant processing units to separate and recover at least one desired fluid (e.g. nitrogen gas, argon gas, etc.). In some embodiments, the process can be configured so that fluid flows output from a low pressure column and/or high pressure column of the plant can provide a condensation duty or refrigeration duty that is utilized to process certain fluid flows for recovery of argon and/or nitrogen gases. Some embodiments can be configured to provide an improved recovery of argon and/or nitrogen as well as an improvement in operational efficiency by reducing an amount of power (e.g. electrical power) needed to recover the nitrogen and/or argon.

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.