EP-4739964-A1 - METHOD FOR THE CRYOGENIC PRODUCTION OF AIR PRODUCTS, AND AIR SEPARATION SYSTEM

Abstract

The invention relates to method for the cryogenic production of air products, in which method an air separation system (100) having a first rectification arrangement (110), a second rectification arrangement (120), and a compressor arrangement (130) is used, the first rectification arrangement (110) and the second rectification arrangement (120) each having a rectification column operated at a pressure level of more than 2 bar, and the method comprising a combined operational mode in which: intake air is subjected to an intake air compression operation using the compressor arrangement (130), and is subsequently supplied in portions to the first rectification arrangement (110) and the second rectification arrangement (120); high-purity nitrogen is provided using the first rectification arrangement (110) and the second rectification arrangement (120); and high-purity nitrogen provided using the first rectification arrangement (110) or a portion of said high-purity nitrogen is subjected to a high-purity nitrogen compression operation by means of the compressor arrangement (130). According to the invention: the compressor arrangement (130) has a plurality of first compressor units (131) and a second compressor unit (132), each of the first compressor units (131) having a first compressor stage (131a) and a second compressor stage (131b); the first compressor stage (131a) and the second compressor stage (131b) are mechanically coupled to one another in the first compressor units (131); and, in the combined operational mode, the first compressor stages (131a) of the first compressor units (131) and the second compressor units (132) are used for the intake air compression operation, and the second compressor stages (131b) of the first compressor units (131) are used for the high-purity nitrogen compression operation. The invention also relates to a corresponding air separation system (100).

Inventors

• OTTE, Daniel

Assignees

• Linde GmbH

Dates

Publication Date

20260513

Application Date

20240702

Claims (1)

1. patent claims 1 . A process for the cryogenic production of air products, in which an air separation system (100) with - a first rectification arrangement (110) comprising a double column unit (1 1 1 ), - a second rectification arrangement (120) comprising a nitrogen column (121), and - a compressor arrangement (130), wherein - the first rectification arrangement (1 10) and the second rectification arrangement (120) each have a rectification column operated at a pressure level of more than 2 bar and - the method comprises a combination operating mode in which - using the compressor arrangement (130) feed air of a Feed air compression and then fed in portions to the first rectification arrangement (110) and the second rectification arrangement (120), in which - using the first rectification arrangement (110) a first High purity nitrogen product (1 DESCRIPTION) is provided by removing it from the double column unit (111 ), and using the second rectification arrangement (120) a second high purity nitrogen product (2 DESCRIPTION ) is provided by removing it from the nitrogen column (121 ), and wherein - the first high purity nitrogen product (1 ) using the compressor arrangement (130) is subjected to high-purity nitrogen compression, and - and the second high-purity nitrogen product (2) is not fed into the compressor arrangement (130) is initiated, - the compressor arrangement (130) comprises a plurality of first compressor units (131) and a second compressor unit (132), wherein - each of the first compressor units (131) has a first compressor stage (131 a) and a second compressor stage (131 b), - in the first compressor units (131 ), the first compressor stage (131 a) and the second compressor stage (131 b) are mechanically coupled to one another, and - in the combination operating mode - the first compressor stages (131 a) of the first compressor units (131 ) and the second compressor unit (132) for the feed air compression and - the second compressor stages (131 b) of the first compressor units (131) are used for high-purity nitrogen compression - at least a portion of the high-purity nitrogen compressed in the second compressor stages (131b) of the first compressor units (131) is fed back into the first rectification arrangement (110) as a recycle nitrogen stream. 2. The method according to claim 1, wherein one, several or all of the first compressor units (131) have two to four of the first compressor stages (131a) and/or two to four of the second compressor stages (131b). 3. The method of claim 1 or 2, wherein the compressor assembly (130) comprises two or more of the second compressor units (132). 4. Method according to one of the preceding claims, in which the first compressor stages (131 a) of different first compressor units (131 ) are decoupled from one another and the second compressor stages (131 b) of different first compressor units (131 ) are decoupled from one another. 5. Method according to one of the preceding claims, in which - the first rectification arrangement (110) comprises an argon recovery column (112) in addition to the double column unit (111), wherein - an argon product is removed from the argon recovery column (112), and - the second rectification arrangement (120) does not have an argon recovery column. 6. Process according to claim 5, in which liquid is withdrawn from the nitrogen column (121), expanded, evaporated against condensing top gas of the second nitrogen column (121), and at least partially subjected to recompression and fed back into the second nitrogen column (121). 7. A method according to any one of the preceding claims, comprising a first single operating mode in which the feed air is subjected to compression and is supplied only to the first rectification arrangement (110), and in which - at least a part of the first compressor units (131) is operated and - the second compressor unit (132) is not operating. 8. The method of claim 7, comprising a second single mode of operation in which the feed air is subjected to compression and supplied only to the second rectification arrangement (120), and in which the second compressor unit (132) is operated and the first compressor units (131) are not operated. 9. The method according to claim 7 or claim 8, wherein the combination operating mode and/or the first individual operating mode comprises a design operating mode in which all of the first compressor units (131) are operated and one or more special operating modes in which at least one of the first compressor units (131) is not operated. 10. The method of claim 9, wherein the special operating mode or at least one of the plurality of special operating modes is a maintenance operating mode in which an amount of the feed air subjected to compression is the same as in the design operating mode. 11. The method of claim 9 or claim 10, wherein the special operating mode or at least one of the plurality of special operating modes is a load reduction operating mode in which an amount of the feed air subjected to compression is less than in the design operating mode. 12. Method according to one of claims 9 to 11, wherein the special operating mode or at least one of the several special operating modes is a circulation reduction mode, - in the design operating mode, a first amount of nitrogen as Recycle nitrogen stream is fed back into the first rectification arrangement (110) and - in the recycle reduction mode, a second amount of nitrogen, which is smaller than the first amount of nitrogen, is passed back to the first rectification arrangement (110) as a recycle nitrogen stream. 13. Method according to one of the preceding claims, which - two or more first rectification arrangements (110) comprising a double column unit (111), and/or - two or more second rectification arrangements (120) comprising a nitrogen column (121), wherein - first high-purity nitrogen products (1 ) from all second rectification arrangements are subjected to high-purity nitrogen compression using the compressor arrangement (130) and - no second high-purity nitrogen product (2) from one of the first rectification arrangements is introduced into the compressor arrangement (130). 14. Air separation system (100) for the cryogenic production of air products with a first rectification arrangement (110), a second rectification arrangement (120) and a compressor arrangement (130), wherein the first rectification arrangement (110) and the second rectification arrangement (120) each have a rectification column designed for operation at more than 2 bar and the air separation system (100) is designed to carry out a combination operating mode and in this, using the compressor arrangement (130), to subject feed air to feed air compression and then to supply it in portions to the first rectification arrangement (110) and the second rectification arrangement (110), to provide high-purity nitrogen using the first rectification arrangement (110) and the second rectification arrangement (110), and to use the high-purity nitrogen provided using the first rectification arrangement (110) or a portion of the high-purity nitrogen provided using the first rectification arrangement (110) to subject the compressed air to a high-purity nitrogen compression using the compressor arrangement (130), characterized in that the compressor arrangement (130) comprises a plurality of first compressor units (131) and a second compressor unit (132), wherein each of the first compressor units (131) comprises a first compressor stage (131 a) and a second compressor stage (131 b), and in the first compressor units (131) the first compressor stage (131 a) and the second compressor stage (131 b) are mechanically coupled to one another and wherein the air separation system (100) is adapted to use, in the combination operating mode, the first compressor stages (131 a) of the first compressor units (131 ) and the second compressor unit (132) for the feed air compression and the second compressor stages (131 b) of the first compressor units (131 ) for the high-purity nitrogen compression. 15. Air separation system (100) according to claim 14, which is set up to carry out a method according to one of claims 1 to 13.

Description

Description Process for the cryogenic production of air products and air separation system The present invention relates to a process for the cryogenic production of air products and an air separation system. background The production of air products in liquid or gaseous state by low-temperature separation of air in air separation plants is known and is described, for example, in H.-W. Häring (ed.), Industrial Gases Processing, Wiley-VCH, 2006, in particular section 2.2.5, "Cryogenic Rectification". With regard to the technical background of the present invention, reference is made to the relevant literature. US 5,582,034 A discloses a process for producing nitrogen by low-temperature separation of air, in which a single rectification column is used. Liquids with different nitrogen and oxygen contents are taken from a lower area of the rectification column. The liquids are used in a condenser evaporator to condense nitrogen-rich top gas from the rectification column in order to provide a return for the rectification column. After evaporation of the liquid, which is richer in nitrogen and less oxygen, the gas formed, or a portion thereof, is recompressed, cooled and fed back into the rectification column. This gas is also referred to as the "residual gas cycle stream". The liquid, which is poorer in nitrogen and more oxygen-rich, can also be expanded in an expansion turbine after appropriate evaporation, which drives a booster to recompress the residual gas cycle stream. Additional top gas from the rectification column is discharged from the air separation plant as nitrogen product. WO 2021/180362 A1 also describes different methods of this type, which the applicant also refers to as SPECTRA methods. The explanations on page 2 of this publication and the description of Figure 1 therein are expressly referred to here. WO 2020/083528 A1 describes a A large number of configurations are described in which, for example, pure oxygen columns and/or argon columns are used in addition to the original single rectification column for nitrogen recovery. In addition, double column processes for the simultaneous recovery of compressed nitrogen and argon are known, for example from WO 2023/030679 A1. The demand for air products from consumers such as chip manufacturers can fluctuate, both in terms of the amount and type of air products. For example, argon may only be required at certain times, or the amount of pure nitrogen required may fluctuate. The product ratio required in each case, for example argon and/or oxygen to nitrogen, can under certain circumstances mean that the construction of different types of systems of the type described above is advantageous in terms of construction costs. For corresponding purposes, air separation systems with several rectification arrangements can also be used, which only operate together at certain times and individually at other times and deliver corresponding air products. However, there is still a need for improved processes and air separation systems of this type. disclosure of the invention Against this background, a method for the cryogenic production of air products and an air separation system with the features of the respective independent patent claims are proposed. Embodiments are the subject of the dependent patent claims and the following description. The devices used in an air separation plant are described in the cited technical literature, for example in Häring in Section 2.2.5.6, "Apparatus". Unless the following definitions deviate from this, explicit reference is made to the cited technical literature for the language used in the present application. A method for the cryogenic production of air products is proposed, in which an air separation system with a first rectification arrangement which has a double column unit (111), a second rectification arrangement which has a nitrogen column (121), and a compressor arrangement is used, wherein the first rectification arrangement and the second rectification arrangement each have a rectification column which is operated at a pressure level of more than 2 bar, in particular more than 3 bar, 4 bar or 5 bar, and in particular up to 10 bar, 12 bar or 15 bar. The first and second rectification arrangements are decoupled in particular to the extent that no fluids are exchanged between them, ie are transferred from the first to the second rectification arrangement and vice versa, or this only happens to a very small extent, e.g. to less than 10% of a total amount of the fluids treated in the first and second rectification arrangements. The two "rectification arrangements" represent separate trains, i.e. they can basically be operated independently of one another in the cold part and in particular each have their own cold box or their own set of cold boxes, which is separate from the other rectification arrangement. The air inlets into the cold box(es) of the two rectification arrangements are in particular separate. A nitrog