Method and installation for low temperature separation of air

Abstract

The invention relates to a method for low temperature separation of air using an air separating installation having a distillation column system (100) which has a first, a second, a third and a fourthseparating unit (110-140). Compressed and cooled air is fed into the first separating unit (110), the first separating unit (110) is operated at a first pressure level of 4 to 9 bar of absolute pressure and the second, the third and the fourth separating units (120-140) are operated at a second pressure level of 1 to 3 bar of absolute pressure. An oxygen-enriched, nitrogen-depleted, argon-containing first sump liquid and a nitrogen-enriched, oxygen-depleted first head gas are formed by means of the first separating unit (110). The first sump liquid is at least partially transferred into the fourth separating unit (130). The first head gas is at least partially liquefied and returned to the first separating unit (110). An oxygen-rich second sump liquid and an argon-enriched second head gasare formed by means of the second separating unit (120). The second head gas is introduced in a first fraction into the third separating unit (130) and in a second fraction into the fourth separatingunit (140). At least the predominant part of the argon, which is contained in the quantity of air supplied overall to the distillation column system (100), is separated by means of the third separating unit (130). A liquid return to the second separating unit (120) is provided by means of the third separating unit (130). A fourth sump liquid and a fourth head gas are formed by means of the fourthseparating unit (140), and the fourth sump liquid is at least partially returned to the second separating unit (120). The second separating unit (120) has 10 to 50 theoretical plates, the third separating unit (130) has 10 to 60 theoretical plates, the third separating unit (130) is arranged above the second separating unit (120) and the fourth separating unit (140) is arranged adjacent to the first separating unit (110). The third separating unit (130) opens in a lower region with respect to an upper region of the second separating unit (120), or the third separating unit (130) is connectedto the second separating unit (120) via pipelines which run between an upper region of the second separating unit (120) and a lower region of the third separating unit (130). The present invention also relates to a corresponding installation (200).

Description

[0001] The invention relates to a method for the cryogenic separation of air and a corresponding apparatus according to the preambles of the independent claims. Background technique [0002] The production of liquid or gaseous air products by cryogenic separation of air in an air separation plant is known and for example in Wiley-VCH Publishing Company 2006 by H.-W. Edited and published in the book "Industrial Gases Processing", especially described in chapter 2.2.5 "Cryogenic Rectification". [0003] The air separation plant has a distillation column system which can be designed, for example, as a two-column system, in particular the typical Linde two-column system, but also as a three-column or multi-column system. In addition to the distillation column for the extraction of liquid and / or gaseous nitrogen and / or oxygen, i.e. for the separation of nitrogen and oxygen, it can also be provided for the extraction of other air components, in particular krypton, xenon and / or argo...

AI Technical Summary

Problems solved by technology

In principle, the separation of oxygen and argon in a low-pressure column is inherently cumbersome and requires a corresponding "heating" power in the main condenser

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