A method and a device used to variably obtain a compressed-gas product by means of the low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of high-pressure column nitrogen is compressed in a nitrogen compressor and in the second operating mode, a second, larger amount is compressed in the nitrogen compressor.

A cryogenic air separation method and apparatus in which first and second liquid streams are produced. The first liquid stream has a higher oxygen content than air and can consist of a higher pressure distillation column bottoms and the second liquid stream, for instance, air, has a lower oxygen content than the first liquid stream and an argon content no less than the air. The second liquid stream is subcooled through indirect heat exchange with the first liquid stream and both of such streams are introduced into the lower pressure column. The second liquid stream is introduced into the lower pressure column above that point at which the crude liquid oxygen column bottoms or any portion thereof is introduced into the lower pressure column to increase a liquid to vapor ratio below the introduction of the second liquid stream and therefore, reduce the oxygen present within the column overhead.

A method for the low-temperature separation of air using an air separation plant which comprises a rectification column arrangement (10) having a pressure column, a low-pressure column and an argon column, wherein: the low-pressure column comprises a first and a second rectification region (A, B); the argon column comprises a first and a second rectification region (C, D, D1, D2); argon-enriched fluid is removed from the low-pressure column between the first and second rectification region (A, B) thereof and is fed into the first rectification region (C) of the argon column; and argon-depleted fluid is removed from the first rectification region (C) of the argon column (13a, 13b) and is fed into the low-pressure column between the first and second rectification region (A, B) thereof.

A method for obtaining one or more air products by means of an air separation unit comprising a first booster, a second booster, a first decompression machine, and a rectification column system which has a high-pressure column operated at a first pressure level and a low-pressure column operated at a second pressure level below the first pressure level. All of the air supplied to the rectification column system is first compressed to a third pressure level, which lies at least 3 bar above the first pressure level, as a feed air quantity. A first fraction of the feed air quantity is supplied to a first booster at the third pressure level and at a temperature level of 140 to 70 C. and is compressed to a fourth pressure level using the first booster.

A method and a device used to variably obtain a compressed-gas product by means of the low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of high-pressure column nitrogen is compressed in a nitrogen compressor and in the second operating mode, a second, larger amount is compressed in the nitrogen compressor.

A method for the cryogenic separation of air, in which method an air separation plant with a rectification column arrangement is used, which plant has a pressure column, a low-pressure column, a raw argon column and pure argon column. In the method, evaporation gas from a head gas condensation device associated with the raw argon column is partially or completely fed into the low-pressure column in a first feed-in region, whereas evaporation gas from a head gas condensation device associated with the pure argon column and excess liquid from this head gas condensation device are partially or completely fed into the low-pressure column in a shared second feed-in region. In one embodiment, flash gas forming during the expansion of cooling fluid into the head gas condensation device associated with the raw argon column can be partially or completely fed into the low-pressure column in the second feed-in region.

A method and device used to variably obtain a compressed-gas product by means low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of air is compressed in the main air compressor, and in the second operating mode, a second, larger amount is compressed in the main air compressor.

An object of the present invention is to provide an argon column for an air separation unit in which the height of the distillation column is reduced without reducing distillation performance. The present invention provides an argon column for an air separation unit including an upper section and a lower section; the upper section and the lower section both have a bed having the same bed length within the same section; the upper section length is 72% or less of the total bed length; and the upper bed length is 1.25 times or more than the lower bed length.

An air fractionation plant in which a cooling water circuit having a recooling apparatus is provided for cooling compressed air, where the recooling apparatus is configured for cooling cooling water using cooling air. The recooling apparatus is configured so as to cool the cooling water, at least at a wet bulb temperature of the cooling air of more than 289 K, to a temperature which is not more than 3 K above the wet bulb temperature. A corresponding operating method and a control facility are likewise provided.

An air separation apparatus comprises: a first rectification column, a first condensing portion, a second rectification column, a third rectification column, a second condensing portion, a fourth rectification column, a third condensing portion, and a recycling pipe for recycling a gas drawn from the third condensing portion to the second rectification column. The air separation apparatus furthermore comprises: a branch pipe branching from the recycling pipe; and a control unit for controlling opening/closing of a valve so that a gas drawn from the third condensing portion is fed to the branch pipe for a predetermined period from the start of driving of the third condensing portion, and for controlling opening/closing of the valve so that the gas drawn from the third condensing portion is fed to the recycling pipe after the predetermined period has elapsed.