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.

Plant for the production of argon by cryogenic distillation, comprising an argon separation column, means for sending a gas containing argon and oxygen to the argon separation column, means for extracting a fluid enriched in argon at the top of the argon separation column, means for extracting a liquid enriched in oxygen at the bottom of the argon separation column and at least two storage tanks, positioned one above the other, each storage tank being connected to two different intermediate levels of the argon separation column by two pipes, the two storage tanks being contiguous.

Plant for the production of argon by cryogenic distillation, comprising an argon separation column, means for sending a gas containing argon and oxygen to the argon separation column, means for extracting a fluid enriched in argon at the top of the argon separation column, means for extracting a liquid enriched in oxygen at the bottom of the argon separation column and at least two storage tanks, positioned one above the other, each storage tank being connected to two different intermediate levels of the argon separation column by two pipes, the two storage tanks being contiguous.

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.

A nitrogen generating method for producing product nitrogen using a nitrogen generating device comprising a main heat exchanger for cooling feed air, a nitrogen rectification column into which the feed air cooled in the main heat exchanger is introduced, and a nitrogen condenser which condenses a vapour stream fed from the nitrogen rectification column and circulates the same to the nitrogen rectification column, the method including a control step for discharging liquid nitrogen condensed by the nitrogen condenser and stored in a liquid nitrogen buffer, which is provided in an upper gas phase portion of the nitrogen rectification column or separately from the nitrogen rectification column, to a rectification portion of the nitrogen rectification column in response to an increase in an amount of product nitrogen or an increase in a flow rate of the feed air.

The invention relates to a cryogenic distillation apparatus for a gas mixture, including a purification apparatus for purifying a gas mixture in a system with a plurality of adsorbant bottles, a column system, a capacity, means for feeding a cryogenic liquid to the capacity, means for feeding a vaporized liquid from the capacity to a column of the system, a vaporizer in the capacity for vaporizing the contained liquid; means for feeding a calorigenic gas to the vaporizer, and means for drawing a liquid from the capacity.