Method for operating an air separation plant, having a distillation column system, a heat exchanger and an adsorber, and air separation plant

A method for operating an air separation plant which comprises:

• a distillation column system;
• a heat exchanger;
• and an adsorber, in which
• in a first time period, a first operating mode is carried out and, in a second time period following the first time period, a second operating mode is carried out, the first and second time periods being carried out multiple times alternately,
• in the first operating mode, compressed air is at least partially freed of water and carbon dioxide in the adsorber and at least part of said compressed air is cooled in the heat exchanger,
• in the first operating mode, an air product is removed from the distillation column system and at least part of said air product is heated in the heat exchanger,
• in the first operating mode, a first end of the heat exchanger is brought to a first temperature level and a second end of the heat exchanger is brought to a second temperature level below the first temperature level,
• in the second operating mode, the cooling of the compressed air and the heating of the air product in the heat exchanger are partially or completely suspended, and
• in the second operating mode, heating of the second end of the heat exchanger to a third temperature level above the second temperature level is allowed,
• wherein
• in a third time period between the second time period and the first time period, a third operating mode is carried out,
• in the third operating mode, compressed air is at least partially freed of water and carbon dioxide in the adsorber and at least part of said compressed air is cooled in the heat exchanger,
• in the third operating mode, the air product is removed from the distillation column system and at least part of said air product is heated in the heat exchanger, and
• in the third operating mode, an adjustable portion of the compressed air cooled in the heat exchanger or an adjustable amount of additional compressed air, which is at least partially freed of water and carbon dioxide in the adsorber but is not cooled in the heat exchanger, is fed to the air product before the air product is heated in the heat exchanger.

An air separation plant which comprises:

• a distillation column system;
• a heat exchanger;
• and an adsorber, the air separation plant being designed
• to carry out a first operating mode in a first time period and a second operating mode in a second time period which is after the first time period,
• in the first operating mode, to free compressed air at least partially of water and carbon dioxide in the adsorber and to cool at least part of said compressed air in the heat exchanger,
• in the first operating mode, to remove an air product from the distillation column system and to heat at least part of said air product in the heat exchanger,
• in the first operating mode, to bring a first end of the heat exchanger to a first temperature level and a second end of the heat exchanger to a second temperature level below the first temperature level,
• in the second operating mode, to partially or completely suspend the cooling of the compressed air and the heating of the air product in the heat exchanger, and
• in the second operating mode, to allow heating of the second end of the heat exchanger to a third temperature level above the second temperature level,
• wherein the plant is designed
• in a third time period between the second time period and the first time period, to carry out a third operating mode,
• in the third operating mode, to free compressed air at least partially of water and carbon dioxide in the adsorber and to cool at least part of said compressed air in the heat exchanger,
• in the third operating mode, to remove the air product from the distillation column system, and to heat at least part of said air product in the heat exchanger, and
• in the third operating mode, to feed an adjustable portion of the compressed air cooled in the heat exchanger or an adjustable amount of additional compressed air which is at least partially freed of water and carbon dioxide in the adsorber, but is not cooled in the heat exchanger, to the air product before the air product is heated in the heat exchanger.