Method for the cryogenic production of air products, and air separation system
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- LINDE AG
- Filing Date
- 2024-07-02
- Publication Date
- 2026-05-13
Smart Images
Figure EP2024025195_09012025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Process for the cryogenic production of air products and air separation system
[0003] The present invention relates to a process for the cryogenic production of air products and an air separation system.
[0004] background
[0005] The production of air products in liquid or gaseous form by cryogenic separation of air in air separation plants is known and described, for example, in H.-W. Häring (ed.), Industrial Gases Processing, Wiley-VCH, 2006, particularly Section 2.2.5, "Cryogenic Rectification." For the technical background of the present invention, reference is made to the relevant literature.
[0006] US Pat. No. 5,582,034 A discloses a process for producing nitrogen by cryogenic air separation, using a single rectification column. Liquids with varying nitrogen and oxygen contents are withdrawn from the lower section of the rectification column. The liquids are used in a condenser-evaporator to condense nitrogen-rich overhead gas from the rectification column, thus providing a reflux for the rectification column. After evaporation of the nitrogen-rich and oxygen-poor liquid, the resulting gas, or a portion thereof, is recompressed, cooled, and fed back into the rectification column. This gas is also referred to as the "residual gas recycle stream."The lower-nitrogen and higher-oxygen liquid, also after appropriate evaporation, can be expanded in an expansion turbine, which drives a booster to recompress the residual gas cycle stream. Additional overhead gas from the rectification column is discharged from the air separation plant as a nitrogen product.
[0007] WO 2021 / 180362 A1 also describes various processes of this type, which the applicant also refers to as the SPECTRA process. The explanations on page 2 of this document and the description of Figure 1 therein are expressly incorporated herein by reference. WO 2020 / 083528 A1 describes a variety of configurations in which, for example, pure oxygen columns and / or argon columns are used in addition to the originally single rectification column for nitrogen recovery. Double-column processes for the simultaneous recovery of pressurized nitrogen and argon are also known, for example from WO 2023 / 030679 A1.
[0008] The demand for air products by consumers such as chip manufacturers can fluctuate, both in terms of quantity and type. For example, argon may only be needed at certain times, or the amount of pure nitrogen required may fluctuate. The required product ratio of, for example, argon and / or oxygen to nitrogen may, under certain circumstances, make it advantageous to construct different plant types of the type described above in terms of construction costs. For such purposes, air separation systems with multiple rectification arrangements can also be used. These operate together only at certain times and individually at other times, delivering the corresponding air products.
[0009] However, there is still a need for improved processes and air separation systems of this type.
[0010] Disclosure of the invention
[0011] Against this background, a process for the cryogenic production of air products and an air separation system with the features of the respective independent patent claims are proposed. Further embodiments are the subject of the dependent patent claims and the following description.
[0012] The devices used in an air separation plant are described in the cited specialist literature, for example in Häring in Section 2.2.5.6, "Apparatus". Therefore, unless the following definitions deviate from this, explicit reference is made to the cited specialist literature for the terminology used in the present application. A process for the cryogenic production of air products is proposed, in which an air separation system is used with a first rectification arrangement having a double column unit (111), a second rectification arrangement having a nitrogen column (121), and a compressor arrangement, wherein the first rectification arrangement and the second rectification arrangement each have a rectification column 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 transferred from the first to the second rectification arrangement and vice versa, or this occurs at most 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.
[0013] The two "rectification arrangements" represent separate trains, meaning they can essentially be operated independently of each other in the cold section and, in particular, each have their own cold box or set of cold boxes, separate from the other rectification arrangement. The air inlets into the cold box(es) of the two rectification arrangements are, in particular, separate. A nitrogen column, as used in the second rectification arrangement, is formed by a single column with a top condenser. The second rectification arrangement may, but need not, have one or more additional columns, such as a pure oxygen column. A double-column unit consists of a high-pressure column, a low-pressure column, and a condenser-evaporator (main condenser), via which the two columns are in heat exchange relationship.The first rectification arrangement may, but need not, comprise one or more further columns, in particular for the recovery of one or more noble gases, for example argon.
[0014] It is provided that the method comprises a combined operating mode, wherein in the combined operating mode, feed air is subjected to feed air compression using the compressor arrangement and is then fed in portions to the first rectification arrangement and the second rectification arrangement. The first rectification arrangement can be assigned, in particular, a first main heat exchanger, and the second rectification arrangement can be assigned, in particular, a second main heat exchanger, wherein the portion of the air used to feed the first rectification arrangement is passed through the first main heat exchanger and the portion of the air used to feed the second rectification arrangement is passed separately through the second main heat exchanger, ieThe portion of the air used to feed the first rectification system is not passed through the second main heat exchanger, and the portion of the air used to feed the second rectification system is not passed through the first main heat exchanger. Here, too, small amounts of, for example, less than 10% of the feed air can be treated differently.
[0015] It is further provided that in the combined operating mode, high-purity nitrogen is provided using the first rectification arrangement and the second rectification arrangement, and in the combined operating mode, the first high-purity nitrogen product provided using the first rectification arrangement is subjected to high-purity nitrogen compression using the compressor arrangement. The second high-purity nitrogen product from the second rectification arrangement is not introduced into the compressor arrangement.
[0016] Of course, in addition to the first high-purity nitrogen product, a further high-purity nitrogen stream can be obtained from the first rectification arrangement, which, for example, is withdrawn together with the first high-pressure nitrogen product from the double column, but is not fed to the compressor arrangement.
[0017] Furthermore, in the invention, at least a portion of the high-purity nitrogen compressed in the second compressor stages of the first compressor units is returned to the first rectification arrangement as a recycle nitrogen stream. The remainder is typically recovered as the final product.
[0018] In the present case, “high-purity nitrogen” is understood to mean in particular gaseous nitrogen with a very low oxygen content, which can in particular be in the single-, double- or triple-digit ppb range (parts per billion, billionths of a part), i.e. in particular less than 100, 50, 10.5, 1, 0.5 or 0.1 ppb. An argon content can typically be higher, for example in the single-, double- or triple-digit ppm range (parts per million, millionths of a part) or less, i.e. in particular less than 100, 50, 10.5, 1, 0.5 or 0.1 ppb. The high-purity nitrogen compression takes place in particular from a pressure in a pressure range of 2 to 5 bar to a pressure in a pressure range of 8 to 15 bar. The air compression takes place in particular from atmospheric pressure to a pressure in a pressure range of 8 to 15 bar.The high-purity nitrogen from the second rectification arrangement can in particular be provided uncompressed as a high-purity nitrogen product.
[0019] It is provided that the compressor arrangement has a plurality of first compressor units and a second compressor unit, wherein each of the first compressor units has a first compressor stage and a second compressor stage, in each of the first compressor units the first compressor stage and the second compressor stage are mechanically coupled to one another, and in the combination operating mode the first compressor stages of the first compressor units and the second compressor unit are used for the feed air compression and the second compressor stages of the first compressor units are used for the high-purity nitrogen compression.
[0020] A "compressor" or "compressor unit," as used here, is a device designed to compress at least one gaseous stream from at least one inlet pressure, at which it is fed to the compressor, to at least one final pressure, at which it is removed from the compressor. A compressor generally forms a structural unit, which may, however, have multiple "compression stages" in the form of piston, screw, and / or impeller or turbine arrangements (i.e., axial or radial compressor stages). This also applies in particular to the "main (air) compressor" of an air separation plant, which is characterized by the fact that it compresses all or the majority of the air volume fed into the air separation plant, i.e., the entire feed air stream.In particular, corresponding compressor stages are driven by a common drive, for example, via a common shaft. The term "compressor units" is used below, whereby specific compressor units may have compressor stages used for different compression purposes, and these compressor stages are mechanically coupled to one another, for example, via a common shaft. The present invention, in its various embodiments, relates in particular to a cost-effective option for providing feed air for different rectification arrangements and simultaneously compressing a high-purity nitrogen product.The following explanations are based on systems with two rectification arrangements, one of which is designed with a double column and has an argon recovery system, and the other is designed as a SPECTRA unit and does not have an argon recovery system. The process proposed here, or a corresponding system, is expandable, in particular with an additional SPECTRA unit for nitrogen recovery.
[0021] A SPECTRA unit with argon recovery is typically equipped (to reduce construction costs) with a four-stage main air compressor and a two-stage nitrogen compressor in a combination machine. A SPECTRA unit without argon recovery is typically equipped with a three- or four-stage main air compressor.
[0022] The present invention was developed specifically for a requirement profile with an N+2 air compressor arrangement. This should enable a 50% reduction in the total gas supply, resulting in 50% of the machines being in operation for each plant. It should also be possible to operate each of the units in the event of maintenance / downtime of the other unit. A conventional solution would therefore result in the use of N+2 machines, i.e. 2+2 for the SPECTRA unit with argon recovery and 2+2 for the SPECTRA unit without argon recovery, and thus eight machines in total. Embodiments of the present invention offer a solution to reduce the number of installed machines to a minimum while still ensuring efficient and flexible operation overall.
[0023] Air separation plants with so-called crude and pure argon columns can be used to produce argon. An example is illustrated by Häring (see above) in Figure 2.3A and described starting on page 26 in the section "Rectification in the Low-pressure, Crude and Pure Argon Column" and starting on page 29 in the section "Cryogenic Production of Pure Argon." Crude argon is extracted in a conventional crude argon column and then processed into pure argon in a downstream pure argon column. In principle, a pure argon column can be dispensed with for argon production if the relevant rectification columns are adapted accordingly. Pure argon can, for example, be withdrawn from the crude argon column or a comparable rectification column further downstream than the fluid conventionally transferred to the pure argon column, with a section located above the extraction point serving to separate nitrogen.The terms “argon recovery column” and “argon recovery system” are also used above and below.
[0024] The invention enables a reduction in construction and operating costs by maintaining flexibility and product requirements through a clever interconnection of air and high-purity nitrogen compression and an intelligent definition of compression requirements. At least one of the compressors, i.e., the second compressor unit, is not a combination compressor and is therefore designed solely for air compression.
[0025] In particular, one, several, or all of the first compressor units can have two to four of the first compressor stages and / or two to four of the second compressor stages. In one, several, or all of the first compressor units, one, several, or all of the first compressor stages can be mechanically coupled to one, several, or all of the second compressor stages. A pairwise coupling of a first and a second compressor stage can also be provided. The above explanations regarding "the" first compressor stage and "the" second compressor stage therefore also apply to such configurations.
[0026] Likewise, in embodiments of the invention, the compressor arrangement may comprise two or more second compressor units, of which one, several or all may then be operated as previously explained.
[0027] The first compressor stages of different first compressor units can be decoupled from one another and the second compressor stages of different first compressor units can also be decoupled from one another.
[0028] In particular, the first rectification arrangement comprises a double column unit with a pressure column and a low-pressure column, as well as an argon recovery column. The high-purity nitrogen provided using the first rectification arrangement is withdrawn from the double column unit, in particular at the top of a pressure column and / or low-pressure column, and an argon product is withdrawn from the argon recovery column. The pressure and low-pressure columns can be installed in a common shell, but can also be provided separately from one another. The low-pressure column can be constructed in one or two parts. The operating pressure of the pressure column can be, in particular, between 9 and 14.5 bar.
[0029] The argon column can also be a one-piece or two-piece design. The first rectification arrangement can comprise one or more rectification columns for producing ultra-high-purity oxygen and / or for producing a crude krypton / xenon mixture and / or for producing a crude helium / neon mixture.
[0030] The second rectification arrangement comprises, in particular, a nitrogen column from which the high-purity nitrogen provided using the second rectification arrangement is withdrawn, and no argon recovery column. It may, in particular, be a rectification column as is known for a SPECTRA system. In particular, the second rectification arrangement may contain exactly one nitrogen column, specifically as the only column, or one or more nitrogen columns may be present together with one or more further columns, in particular for the production of ultra-high-purity oxygen, as explained above.
[0031] The first rectification arrangement or its double-column unit is operated in particular as known per se for corresponding arrangements. In particular, liquid is withdrawn from the nitrogen column of the second rectification arrangement, expanded, vaporized against condensing overhead gas from the second nitrogen column, and at least partially subjected to recompression and fed back into the nitrogen column. The second nitrogen column is in particular of the type of rectification columns described above with reference to publications such as US Pat. No. 5,582,034 A, WO 2021 / 180362 A1, and WO 2020 / 083528 A1, or the SPECTRA process. The aforementioned recompression can be carried out in particular using a booster of a turbine booster coupled to an expansion turbine.
[0032] An "expansion turbine" or "expansion machine," which may be coupled via a common shaft to other expansion turbines or energy converters such as oil brakes, generators, or compressors, is designed to expand a gaseous or at least partially liquid stream. In particular, expansion turbines for use in the present invention can be configured as turboexpanders. If a compressor is driven by one or more expansion turbines, but without externally supplied energy, for example, by means of an electric motor, the term "turbine-driven compressor" or alternatively "turbine booster" is used.
[0033] From the nitrogen column (in the second rectification arrangement), liquids with different nitrogen and oxygen contents can be withdrawn from a lower region, of which the liquid with the higher nitrogen content can in particular be the liquid already mentioned. The liquids can be used in a condenser-evaporator to condense the nitrogen-rich overhead gas from the rectification column, thus providing a reflux for the nitrogen column. After evaporation of the nitrogen-rich and oxygen-poor liquid, the resulting gas, or a portion thereof, can be recompressed, cooled, and fed back into the nitrogen column.
[0034] This gas is also referred to as the "residual gas cycle stream." The liquid, which is lower in nitrogen and richer in oxygen, can be expanded in an expansion turbine, also after appropriate evaporation, which drives a booster to recompress the residual gas cycle stream. Additional overhead gas from the nitrogen column can be discharged from the air separation plant as the nitrogen product.
[0035] In one embodiment of the invention, each of the first compressor units can, as mentioned, have up to four first compressor stages and up to two second compressor stages. A corresponding distribution of compressor stages or the use for the respective purposes can be achieved, in particular, by adapting them to the quantitative ratios of nitrogen and other air components in atmospheric air. In embodiments, the method comprises, in particular, a first individual operating mode in which the feed air is subjected to compression and fed only to the first rectification arrangement, and in which at least some of the first compressor units are operated and the second compressor unit is not operated. In corresponding embodiments, the SPECTRA unit, in particular, can be shut down without argon recovery, for example in order to be able to service it or to reduce the total amount of nitrogen provided.
[0036] In particular, some embodiments also provide a second single operating mode in which the feed air is subjected to compression and fed only to the second rectification arrangement, and in which the second compressor unit is operated and the first compressor units are not operated. In this way, it is possible, in particular, to switch from a combined production of nitrogen and argon to pure nitrogen production with a reduction in the amount of nitrogen.
[0037] The combined operating mode and / or the first individual operating mode can, in particular, comprise a design operating mode in which all first compressor units are operated, and one or more special operating modes in which at least one of the first compressor units is not operated. Corresponding configurations enable adaptation to different product and operational requirements.
[0038] The special operating mode or at least one of the several special operating modes can, in particular, be a maintenance operating mode in which the amount of feed air subjected to compression is the same as in the design operating mode. In such an embodiment, the throughput of the compressor units that continue to be actively operated can be increased.
[0039] The special operating mode or at least one of the several special operating modes can, in particular, also be a load reduction operating mode, in which the amount of feed air subjected to compression is lower than in the design operating mode. In such embodiments, the overall throughput is reduced. The special operating mode or one of the special operating modes can also be a circulation reduction mode.
[0040] - in the design operating mode, a first amount of nitrogen as
[0041] Recycle nitrogen stream is fed back into the first rectification arrangement (110) and
[0042] - in the recycle reduction mode, a second amount of nitrogen, which is smaller than the first amount of nitrogen, is passed back into the first rectification arrangement (110) as a recycle nitrogen stream.
[0043] Within the scope of the invention, various special operating modes can be combined.
[0044] Further operating modes can be provided, for example a maintenance mode in which the first and second rectification arrangements are in operation and two or three of the first or second compressor stages are in operation. In this case, the second compressor stages can be operated in the internal circuit. Furthermore, there is the possibility that only the second rectification order is in operation and only one combination compressor with first and second compressor stages is in operation, with the second compressor stage being operated in the internal circuit (i.e. in “idle” mode). The same applies accordingly for a plurality of first and second compressor stages, if provided in a first compressor arrangement in one embodiment.
[0045] In the method according to the invention, it may be advantageous that a first prepurification unit and a first main heat exchanger unit are assigned to the first rectification arrangement, and that a second prepurification unit and a second main heat exchanger unit are assigned to the second rectification arrangement.
[0046] Two prepurification units and two main heat exchanger units of a known type can be used. One of the two prepurification units and one of the two main heat exchanger units can be assigned to the first rectification arrangement, and the other of the two prepurification units and the two main heat exchanger units can be assigned to the second rectification arrangement. A "rectification arrangement" is therefore understood here as the corresponding combinations of apparatus. The proposed air separation system for the cryogenic production of air products comprises a first rectification arrangement, a second rectification arrangement, and a compressor arrangement, wherein the first rectification arrangement and the second rectification arrangement each have a rectification column configured for operation at more than 2 bar, and the air separation system is configured toto carry out a combination operating mode and, in this mode, to subject feed air to feed air compression using the compressor arrangement and then to supply it in portions to the first rectification arrangement and the second rectification arrangement, to provide high-purity nitrogen using the first rectification arrangement and the second rectification arrangement, and to subject the high-purity nitrogen provided using the first rectification arrangement or a portion thereof to high-purity nitrogen compression using the compressor arrangement.
[0047] The proposed compressor arrangement comprises a plurality of first compressor units and a second compressor unit, wherein each of the first compressor units has a first compressor stage and a second compressor stage, and in each of the first compressor units, the first compressor stage and the second compressor stage are mechanically coupled to one another. The air separation system is configured to use the first compressor stages of the first compressor units and the second compressor unit for feed air compression and the second compressor stages of the first compressor units for high-purity nitrogen compression in the combined operating mode.
[0048] For further features and advantages of a corresponding air separation system and embodiments thereof, reference is expressly made to the above explanations concerning the process proposed according to the invention and its embodiments, since these apply equally to this.
[0049] The same applies to an air separation system which, according to one embodiment of the invention, is configured to carry out a process according to any embodiment of the present invention. Brief description of the drawing
[0050] Embodiments of the invention are described below purely by way of example with reference to the accompanying drawings and explanation of the technical background.
[0051] Figure 1 illustrates an air separation system according to an embodiment of the present invention in a simplified schematic representation.
[0052] Figure 2 illustrates operating modes of an air separation system according to an embodiment of the present invention.
[0053] Embodiments of the invention
[0054] The embodiments described below are described solely for the purpose of assisting the reader in understanding the claimed and previously discussed features. They are merely representative examples and are not intended to be exhaustive and / or limiting with regard to the features of the invention. It is to be understood that the advantages, embodiments, examples, functions, features, structures, and / or other aspects described above and below are not to be considered as limitations on the scope of the invention as defined in the claims or as limitations on equivalents to the claims, and that other embodiments may be utilized and changes may be made without departing from the scope of the claimed invention.
[0055] Different embodiments of the invention may include, have, consist of, or consist essentially of other useful combinations of the described elements, components, features, parts, steps, means, etc., even if such combinations are not specifically described herein.
[0056] Furthermore, the disclosure may encompass other inventions that are not currently claimed but may be claimed in the future, particularly if they are encompassed by the scope of the independent claims. Explanations relating to devices, apparatuses, arrangements, systems, etc. according to embodiments of the present invention may also apply to methods, processes, methods, etc. according to the embodiments of the present invention, and vice versa. Identical, functionally equivalent, structurally identical, or comparably constructed elements, method steps, etc. may be identified by identical reference numerals.
[0057] Figure 1 illustrates an air separation system according to an embodiment of the present invention in a first representation.
[0058] The air separation system is designated overall by 100. It comprises a first rectification arrangement 110, a second rectification arrangement 120, and a compressor arrangement 130. The first rectification arrangement 110 and the second rectification arrangement 120 are each illustrated in the form of cold boxes, with a double column system 111 and an argon column 112 being indicated in the first rectification arrangement 110, and a nitrogen column 121 being indicated in the second rectification arrangement 120. Furthermore, a main heat exchanger 116 and 126 for cooling feed air is illustrated in each case. For specific configurations of the aforementioned column (systems), express reference is made to the prior art mentioned above.Using the first rectification arrangement 110 and the second rectification arrangement 120, when in operation, high-purity nitrogen is generated, which is withdrawn in particular at the top of a (not separately designated) low-pressure column of the double column system 111 or the nitrogen column 121. Corresponding pure nitrogen streams are designated 1 and 2, respectively. Argon, which is also provided in the first rectification arrangement 110, as well as any other air products such as high-purity oxygen, are not shown separately.
[0059] The compressor arrangement 130 here has three identically designated first compressor units 131, each illustrated in the form of two compressor symbols, and a second compressor unit 132, which is also illustrated with a compressor symbol. Each of the first compressor units 131 has a plurality of first compressor stages 131a and a plurality of second compressor stages 131b. Specific details regarding the compressor stages can be found above. In each of the first compressor units 131, the first compressor stages 131a are mechanically coupled to the second compressor stages 131b, for example, via a common axis, as illustrated in each case by a vertical line, or via a gear.
[0060] When in operation, the first compressor stages 131a each draw in feed air in the form of feed air streams 3 via a filter unit 133, as does the second compressor unit 132 or its compressor stages 132a. An aftercooler can be connected downstream of the compressor stages 131a or 132a, respectively. Depending on the operating mode, the correspondingly compressed feed air can be collected in a collecting line 4 via downstream valves (not separately designated) and, via further valves (not separately designated), divided between a first prepurification unit 115 or a second prepurification unit 125, or fed to only one of these, and then likewise divided between the first rectification arrangement 110 and the second rectification arrangement 120, or fed to only one of these. The feed air is freed from water and carbon dioxide in the prepurification units 115 and 125 and cooled in the main heat exchangers 116 and 126, respectively.Residual gas 5 from the rectification arrangements 110 and 120 can be used for regeneration in the prepurification units 115 and 125, respectively.
[0061] The high-purity nitrogen stream 1 from the first rectification arrangement 110 is fed to a distribution line 6 and from there, via valves (not specifically designated), to a suction side of the second compressor stages 131b of the first compressor units 131, as well as to each of the two compressor units 131. A portion can be discharged from the air separation system 100 as product stream 7. After compression in the second compressor stages 131b, the high-purity nitrogen can be fed to a collecting line 8 and from there, returned to the first rectification arrangement 110 as a recycle nitrogen stream or discharged from the air separation system 100 as product stream 9.
[0062] As already mentioned, in a combined operating mode, the first compressor stages 131a of at least one of the first compressor units 131 and the second compressor units 132 can be used for feed air compression, and the second compressor stages 131b of the at least one first compressor unit 131 can be used for high-purity nitrogen compression. In a first individual operating mode, the feed air is subjected to compression and fed only to the first rectification arrangement 110, and in this first individual operating mode, at least a portion of the first compressor units 131 is operated and the second compressor unit 132 is not operated. In a second individual operating mode, the feed air is subjected to compression and fed only to the second rectification arrangement 120, and in this second individual operating mode, the second compressor unit 132 is operated and the first compressor units 131 are not operated.The combination operating mode and / or the first individual operating mode may comprise a design operating mode in which all first compressor units are operated and one or more special operating modes in which at least one of the first compressor units is not operated.
[0063] Corresponding operating modes are explained below with reference to Figure 2, which illustrates eleven views A to L of the first compressor units 131 with the first and second compressor stages 131a, 131b, and the second compressor units 132 with the compressor stages 132a. The compressor units 131 and 132 with the compressor stages 131a, 131b, and 132a are only shown in view A. Compressor units not in operation are shown crossed out. Numbers within the symbols illustrating the compressor stages 131a, 131b, and 132a indicate the respective throughput, for example, in thousands of standard cubic meters per hour. These are merely illustrative examples that do not limit the subject matter of the invention.
[0064] View A represents a combined and design operating mode in which all of the first compressor units 131 and the second compressor unit 132 are in operation. Theoretically, 240,000 standard cubic meters per hour of feed air and 150,000 standard cubic meters per hour of high-purity nitrogen can be compressed.
[0065] View B shows a first individual operating mode in the design operating mode, in which the second compressor unit 132 is not in operation. A total feed air volume of 120 standard cubic meters per hour of feed air is compressed equally by the three first compressor units 131 or their first compressor stages 131a. The same applies to the total of 99,000 (or 100,000) standard cubic meters per hour of high-purity nitrogen, which are compressed using the second compressor stages 131b. View C also shows a first individual operating mode, in which the second compressor unit 132 is not in operation. However, here too, one of the first compressor units 131 is not in operation, so that a special operating mode exists. The total feed air quantity of 120,000 standard cubic meters per hour of feed air is compressed in equal parts by means of the two first compressor units 131 or their first compressor stages 131a.The same applies to the total of 100,000 standard cubic metres per hour of high-purity nitrogen, which are compressed using the second compressor stages 131 b.
[0066] Views B and C correspond in particular to an operating case in which a maximum amount of liquid is to be provided.
[0067] The operating modes illustrated in views D and E are essentially the same as the operating modes illustrated in views B and C, but are set, for example, to cover a maximum liquid oxygen content.
[0068] The operating modes illustrated in views D and E are also essentially the same as those illustrated in views B and C, except that the flow rate is reduced. This first single-mode and special operating mode can be used, for example, to cover a maximum gas flow rate.
[0069] If there is only a significantly reduced demand for corresponding air products at certain times, the first single-operation and special operation mode can be set as shown in view H. In this mode, only one of the first compressor units 131 is in operation and delivers correspondingly small quantities.
[0070] Views I and K show second operating modes in which only the second compressor unit 132 is operating, and here, additionally, with different flow rates. View L, in turn, shows a combined operating mode.
Claims
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) is used, 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 combined 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 (131a) and a second compressor stage (131b), - 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) comprise two to four of the first compressor stages (131a) and / or two to four of the second compressor stages (131b).
3. The method according to claim 1 or 2, wherein the compressor arrangement (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 withdrawn from the argon recovery column (112), and in which - the second rectification arrangement (120) does not have an argon recovery column.
6. A process according to claim 5, wherein 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 operated.
8. The method of claim 7, comprising a second single operating mode in which the feed air is subjected to compression and is 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 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 into 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. An air separation system (100) for the cryogenic production of air products, comprising 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 configured for operation at more than 2 bar, and the air separation system (100) is configured to carry out a combined operating mode and, in this mode, to subject feed air to feed air compression using the compressor arrangement (130) 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 subject the high-purity nitrogen provided using the first rectification arrangement (110) or a portion thereof to 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) has a first compressor stage (131a) and a second compressor stage (131b), and in the first compressor units (131), the first compressor stage (131a) and the second compressor stage (131b) are mechanically coupled to one another, and wherein the air separation system (100) is configured 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. An air separation system (100) according to claim 14, which is arranged to carry out a process according to any one of claims 1 to 13.