CN118532889A - Cryogenic air separation plant and method for cryogenically separating air - Google Patents
Cryogenic air separation plant and method for cryogenically separating air Download PDFInfo
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- CN118532889A CN118532889A CN202410718297.9A CN202410718297A CN118532889A CN 118532889 A CN118532889 A CN 118532889A CN 202410718297 A CN202410718297 A CN 202410718297A CN 118532889 A CN118532889 A CN 118532889A
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- 238000000926 separation method Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 239000000047 product Substances 0.000 claims description 63
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 41
- 229910052757 nitrogen Inorganic materials 0.000 claims description 21
- 239000007789 gas Substances 0.000 claims description 20
- 239000012263 liquid product Substances 0.000 claims description 18
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 16
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 14
- 238000001704 evaporation Methods 0.000 claims description 12
- 229910052786 argon Inorganic materials 0.000 claims description 7
- 230000008020 evaporation Effects 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 5
- 230000003028 elevating effect Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 abstract description 8
- 230000006835 compression Effects 0.000 abstract description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 11
- 239000001301 oxygen Substances 0.000 description 11
- 229910052760 oxygen Inorganic materials 0.000 description 11
- 238000005265 energy consumption Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 1
- 238000004887 air purification Methods 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention provides a cryogenic air separation plant and a method of cryogenically separating air having a main air compressor, a single expansion turbine, and a turbocharger, main heat exchanger and rectifying column system driven thereby. The method for separating air at low temperature is suitable for the situation that the pressure of the first product after internal compression is not higher than 6bara, and the range of the liquid production ratio is 20% -30%. The feed air is compressed in a main air compressor to a first pressure air stream at least 6bara above the operating pressure of the higher pressure column, a first portion of the first pressure air stream is compressed in a turbocharger to form a second pressure air stream, the second pressure air stream is partially cooled in the main heat exchanger and then directed to an expansion turbine, and after expansion depressurization, is directed to a rectification column system; the second part of the first pressure air stream is fed into the rectification column system after being completely cooled in the main heat exchanger and throttled and depressurized. The air separation plant of the invention does not comprise an air booster driven by externally supplied energy.
Description
Technical Field
The invention belongs to the field of air separation, relates to a method for separating air at low temperature and a low-temperature air separation device, and particularly relates to a method and equipment for obtaining low-temperature separated air of a pressurized gas product by adopting an internal compression process.
Background
The production of air products such as oxygen, nitrogen, argon, etc. by cryogenic rectification of air is a known technique. Cryogenic rectification plants typically include a main air compressor, an air pre-cooling and purification system, a main heat exchanger and a rectification column system and utilize externally introduced cryogenic liquid (e.g., liquid nitrogen) or expansion of air to produce the cold required for cryogenic separation. The rectification column system may comprise a single column, or double and triple columns coupled by heat exchange, etc. By way of example, a rectification column system in the form of a double column is composed of a lower pressure column and a higher pressure column, respectively, operating at relatively low and high pressures, and is capable of producing products such as nitrogen and oxygen in both gaseous and liquid states.
When customers require gas products at a pressure higher than the operating pressure of the higher or lower pressure columns, the prior art uses either an external or internal compression scheme. The external compression process refers to a process of vaporizing (aiming at the liquid product) and reheating the liquid or gaseous product taken out from the rectifying tower in a main heat exchanger without changing the pressure of the liquid or gaseous product, and compressing the corresponding reheated gaseous product to a gas product with a gas compressor at a pressure required by a customer.
The internal compression process is a process of raising the pressure of a liquid product taken out from a rectifying tower to a pressure required by a customer by a liquid pump, and then evaporating, pseudo-evaporating and reheating in a main heat exchanger to obtain a gas product with proper pressure.
When the gas product required by the customer is a pressurized oxygen product, for safety and oxygen utilization, an internal compression process is preferred in which the liquid oxygen stream is pumped to the pressure required by the customer and vaporized and reheated in the main heat exchanger using the high pressure air of the forward flow. In the prior art, an air booster is often used after a main air compressor to obtain positive-flow high-pressure air, for example, US5,515,687 and CN108253732a, all disclose a method for compressing at least a part of air compressed and pre-cooled by the main air compressor, and compressing the air to the positive-flow high-pressure air with a pressure higher than the pressure of liquid oxygen to be vaporized in an externally-supplied recompressor (i.e., air booster) at normal temperature.
In view of the considerable investment and energy consumption of cryogenic air separation processes, those skilled in the art are working to optimize the process flow for a particular product type in order to increase production efficiency, reduce energy consumption, and save investment and operating costs.
Disclosure of Invention
The present invention is intended to provide a method of cryogenic separation of air and cryogenic air separation plant whereby liquid and gaseous products of a certain pressure and composition are produced more efficiently and cost effectively.
To achieve the above objects, in one aspect, the present invention discloses a method of cryogenically separating air using an air separation plant having a main air compressor, an air pre-cooling and purification system, a single expansion turbine, a single turbocharger, a main heat exchanger, and a rectifying column system having a higher pressure column and a lower pressure column. The turbocharger is driven by an expansion turbine. First compressing all feed air in a main air compressor to a first air pressure, forming a first pressure air stream, the first air pressure being at least 6bara higher than the operating pressure of the higher pressure column; then compressing a first portion of the first pressure air stream in the turbocharger to a second air pressure to form a second pressure air stream, the second pressure air stream being partially cooled in the main heat exchanger and directed to the expansion turbine for expansion depressurization and then to the rectifying column system; simultaneously, completely cooling a second part of the first pressure air flow in the main heat exchanger, and inputting the second part into the rectifying tower system after throttling and depressurization; . Obtaining a liquid product in the air separation equipment, wherein the liquid production ratio of the air separation equipment is in the range of 20% -30%. A liquid first product stream is obtained in the rectifying column system, which is raised to a higher first product pressure in a liquid state, is heat exchanged with a second part of the first pressure air stream in the main heat exchanger, is removed as a first pressure gas product from the air separation plant after evaporation or pseudo-evaporation and re-heating, wherein the air separation plant does not comprise an air booster driven by externally supplied energy.
In the above method, the first air pressure ranges from 12bara to 17bara, and the second air pressure ranges from 17bara to 25bara.
Further, the first product stream comprises liquid oxygen, the first product pressure is no greater than 6bara, and the first pressure gas product is oxygen; preferably, the first product pressure is not higher than 4.5bara.
The liquid product produced by the above process comprises one or more of liquid oxygen, liquid nitrogen or liquid argon.
In another aspect, the present invention discloses a cryogenic air separation plant comprising: a main heat exchanger; a rectifying column system having a higher pressure column and a lower pressure column; a main air compressor characterized by compressing all feed air to a first air pressure and forming a first pressure air stream, said first air pressure being at least 6bara higher than the operating pressure of said higher pressure column; a single turbocharger driven by said expansion turbine for compressing a first portion of said first pressure air stream to a second air pressure and forming a second pressure air stream; a single expansion turbine for receiving the second pressure air stream after partial cooling in the main heat exchanger; means for introducing a second portion of the first pressure air stream into the main heat exchanger, after complete cooling, throttling and depressurizing the second portion to the rectification column system; means for introducing the expanded depressurized second pressure air stream into the rectification column system. Means for elevating the liquid first product stream obtained in the rectification column system to a higher first product pressure; means for exchanging heat in said main heat exchanger with a second portion of the first pressure air stream, a liquid first product stream at a first product pressure, and removing from said air separation plant a first pressure gas product formed after evaporation or pseudo-evaporation and heating; means for removing liquid product obtained in the rectifying column system from the air separation plant, the liquid production ratio of the air separation plant ranging from 20% to 30%; in particular, the air separation plant does not comprise an air booster driven by externally supplied energy.
The invention designs a simple and efficient air separation process, and gas and liquid products are obtained through low-temperature air separation, wherein the pressure of the gas products (especially oxygen) is not higher than 6bara, and the liquid-to-liquid ratio of the liquid products is in the range of 20% -30%. Compared with the traditional air separation process, the invention does not adopt an air booster except the main air compressor, and only adopts a turbocharger driven by an expansion turbine, thereby saving investment and energy consumption.
Drawings
The advantages and spirit of the present invention may be further understood by reference to the following detailed description of the invention and the accompanying drawings.
Fig. 1 is a schematic flow chart of embodiment 1 provided by the present invention.
In the figure: 20-a main air compressor; 21-an air pre-cooling purification system; 22-a turbocharger; 23-an expansion turbine; 24-aftercooler; 25-main heat exchanger; 26-a throttle valve; 27-a liquid pump; 28-condensing evaporator; 29-higher pressure column; 30-a low pressure column; a 50-rectifying column system; 1-feeding air; 2-a first pressure air stream; 3-a first portion of the first pressure air stream; 4-a second pressure air stream; 5-a second portion of the first pressure air stream; 6-a first product stream; 7-nitrogen; 8-dirty nitrogen; 9-liquid oxygen; 10-liquid nitrogen; 11-a first pressure gas product; 100-air separation plant.
Detailed Description
Specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention should be understood not to be limited to such an embodiment described below, and the technical idea of the present invention may be implemented in combination with other known technologies or other technologies having the same functions as those of the known technologies.
The terms "first" and "second" are used for descriptive purposes only and are not intended to be limiting with respect to time sequence, number, or importance, and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of features indicated, but merely to distinguish one feature from another feature in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly specified otherwise. Likewise, the appearances of the phrase "a" or "an" in this document are not meant to be limiting, but rather describing features that have not been apparent from the foregoing. Likewise, unless a particular quantity of a noun is to be construed as encompassing both the singular and the plural, both the singular and the plural may be included in this disclosure. Words of "only" and "only, only" and the like are to be understood as meaning a particular quantity of words, including just one of the words defined thereby.
Modifiers that appear herein before a word similar to "about", "approximately" generally include the present number, and their specific meaning should be understood in conjunction with the context. When a number appears as an end of a range of values, the range of values includes the values of both ends; similarly, where a numerical value is used as an end of an open-ended range, such as in connection with "at least", "up to", "no more than", "no less than", the open-ended range also includes the numerical values of the end points.
It should be understood that in the present invention, "at least one (secondary)" means one (secondary) or a plurality of (secondary). "and/or" is used to describe association relationships of associated objects, meaning that there may be three relationships, e.g., "a and/or B" may mean: only a, only B and both a and B are present, wherein a, B may be singular or plural.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
Here, no natural pressure loss is generally contained in the pressure data. The pressures are herein rated "equal" if the pressure difference between the respective locations is not greater than the natural line loss caused by the pressure loss in the piping, heat exchanger, cooler, adsorber, normal regulator valve (non-throttle valve), etc. The "pressure", "pressure range" in the present invention can accommodate a certain error in absolute pressure. For a specific set of cryogenic air separation plants or cryogenic air separation process, the pressure ranges do not coincide.
The air separation plant 100 of the present invention refers to a combination of devices that receive a feed of feed air and are capable of producing gaseous products and liquid products. Wherein the feed air is air which is not purified at normal temperature and normal pressure, the gas product is generally a gaseous product which is reheated to normal temperature by a heat exchanger and has the pressure and purity meeting the requirements, and the liquid product is generally a liquid product which is not reheated and has the pressure and purity meeting the requirements. The liquid product is often fed directly to a pipe network or storage vessel. The higher the yield of liquid product that is directly withdrawn as product from the air separation plant, the more refrigeration is required by the air separation plant. In practice the molar ratio of all liquid products to oxygen products in the air separation plant is characterized by the liquid-to-liquid ratio, which may comprise Liquid Oxygen (LOX), liquid nitrogen (LIN) or, in the case of argon products, liquid Argon (LAR), and oxygen products comprising Liquid Oxygen (LOX) and Gaseous Oxygen (GOX) calculated as follows:
The rectifying tower system in the invention is a device which receives the feed of low-temperature feed air and separates the air into components such as gaseous or liquid oxygen, nitrogen and the like in a gas-liquid mass transfer mode. The rectification column system 50 is shown in highly simplified form and comprises a column body mounted in a cold box and various equipment mounted inside the column, such as trays, packing, condensing evaporators, etc.; and a pipeline, a valve, etc. for connecting the towers and outputting the rectification product. Rectifying column system 50 includes at least one low pressure column 30 operating at a pressure level of 1.0 to 3.0bara and a high pressure column 29 operating at a pressure level of 4.0 to 7.0bara, wherein the low pressure column and the high pressure column are thermally coupled via a main condensing evaporator 28.
"Compressor" in the present invention refers to a device used to compress at least one gas stream from a starting pressure when it enters the compressor to a final pressure when it is withdrawn from the compressor. A compressor mounted in a housing may contain a single or multiple compression stages. The main air compressor compresses all or a major portion of the air volume fed to the air separation plant, i.e., the entire feed air stream. Compressors in which part or all of the feed air compressed in the main air compressor is compressed to a higher pressure are referred to as recompressors or air superchargers. In the present invention, an air supercharger refers in particular to a compressor driven entirely by externally supplied energy, i.e. a supercharger that is not driven by expansion of a previously compressed fluid in an air separation plant. The air separation plant of the present invention does not comprise an air booster as defined above.
The air pre-cooling system is arranged at the downstream of the main air compressor, cools the feed air to the range of 10-25 ℃ by adopting an air cooling tower, a water cooling tower, a refrigerator or a combination mode, and sends the feed air into the air purifying system. The purpose of the air purification system is to remove substances in the feed air that may freeze in a cryogenic state, such as water, carbon dioxide, hydrocarbons, etc., typically using parallel arranged adsorbers packed with adsorbents such as molecular sieves and alumina.
The "main heat exchanger" is used to cool feed air in indirect heat exchange with a return stream from the rectification column system, such as with dirty nitrogen or cryogenic air separation products. The main heat exchanger may be formed by a single heat exchange section or a plurality of heat exchange sections connected in parallel and/or in series, with "channels" designed as fluid channels separated from each other and having heat exchange surfaces. Complete cooling means that the cooled stream enters the main heat exchanger at the warm end and exits the main heat exchanger from the cold end, i.e. the passage through which the stream flows runs through the entire main heat exchanger; whereas partial cooling means that the cooled stream exits the main heat exchanger from a location intermediate the hot and cold ends, i.e. the passage through which the stream flows does not extend through the entire main heat exchanger.
An "expansion turbine" or "expander" is used to expand a gaseous or at least partially liquid stream under pressure and to perform work in the process. In the present invention, the expansion turbine 23 is coupled with the turbocharger 22 via a common shaft, thereby driving the turbocharger 22. In the ideal case, the work produced by the expansion turbine is transmitted entirely to the corresponding turbocharger which is mechanically connected, without using energy supplied externally, for example by means of an electric motor. A mechanical connection is understood in the present context to mean a fixed or mechanically adjustable rotational speed relationship between the rotating components by means of mechanical components, such as gears, belts, transmissions and the like. In the present invention, only one expansion turbine and one turbocharger driven entirely by it are used.
In the embodiment 1 represented in fig. 1, the feed air 1 is first compressed to a first air pressure in a main air compressor 20 and a first pressure air stream 2 is generated. The first air pressure is at least 6bara higher than the operating pressure of the higher pressure column, i.e. the first air pressure ranges from 12bara to 17bara. After removal of impurities in the air pre-cooling and purification system 21, the first pressure air stream 2 is split into two parts, the first part 3 is further compressed by the turbocharger 22 to a second air pressure and forms a second pressure air stream 4. An after-cooler 24 cooled with cooling water may be provided after the turbocharger 22 to remove the heat of compression from the air separation plant 100. The second pressure air stream 4 is partially cooled in the main heat exchanger 25, enters the expansion turbine 23, is expanded and depressurized to the pressure of the higher pressure column 29, and is fed to the higher pressure column. After complete cooling in the main heat exchanger 25, the second portion 5 of the first pressure air stream 2 is fed to the corresponding higher pressure column and/or lower pressure column after pressure relief to the operating pressure of the rectification column system 50 via a throttle 26.
The rectifying column of example 1 produces a liquid product comprising liquid oxygen 9 and liquid nitrogen 10, which are not taken as reflux to the heat exchange in the main heat exchanger 25 after being led out of the rectifying column system 50. And generating polluted nitrogen 8 and pure nitrogen 7, and taking out the polluted nitrogen and the pure nitrogen as products or realizing the functions of precooling and regenerating a purifier after the polluted nitrogen and the pure nitrogen are reheated in a main heat exchanger in a gaseous form. Stream 6 is a liquid first product stream, in this example liquid oxygen, but also liquid nitrogen or liquid argon, etc., as desired. The liquid pump 27 is arranged to raise the pressure of the first product stream to a higher pressure and the pressurized stream 6 is removed from the air separation plant as the first pressure gas product 11 after evaporation or pseudo-evaporation and reheat in the main heat exchanger 25.
In order to vaporize the pressurized first product stream in the main heat exchanger, a stream of ambient temperature air having a matched pressure and flow rate is provided to the main heat exchanger. In the present invention, this stream is the second portion 5 of the first pressurized air stream 2. When the first product stream is liquid nitrogen or liquid argon, the first air pressure is approximately equal to the pressure of the boosted first product stream, i.e., the first product pressure; when the first product stream is liquid oxygen, the first air pressure is a multiple, e.g., 2 times, of the pressure of the first product obtained after the pressure boost. The present invention is particularly suitable for a first product pressure of not more than 6bara, preferably not more than 4.5bara, where the first air pressure is in the range 12bara to 17bara.
In example 1, taking the first pressure gas product as oxygen as an example, the liquid products are liquid oxygen stream 9 and liquid nitrogen stream 10, the oxygen products are liquid oxygen stream 9 and first pressure gas product 11, and the liquid-to-gas ratio is calculated by adopting the mole number of each stream:
The method and apparatus of the present invention are particularly advantageous when the liquid production ratio of the air separation apparatus is in the range of 20% to 30%, particularly between 20% and 25%. By selecting the appropriate first air pressure and second air pressure such that the turbocharger is fully driven by the work done by the expansion turbine, the energy consumption and the investment in purchasing additional air turbochargers is reduced.
The preferred embodiments of the present invention have been described in the specification, and the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the present invention. All technical solutions that can be obtained by logic analysis, reasoning or limited experiments according to the inventive concept by those skilled in the art shall be within the scope of the present invention.
Claims (6)
1. A method for cryogenic separation of air employing an air separation plant having a main air compressor, an air pre-cooling and purification system, a single expansion turbine, a single turbocharger, a main heat exchanger, and a rectifying column system having a higher pressure column and a lower pressure column, said turbocharger being driven by said expansion turbine,
All feed air is compressed in a main air compressor to a first air pressure, forming a first pressure air stream, said first air pressure being at least 6bara higher than the operating pressure of said higher pressure column,
A first part of the first pressure air stream is recompressed in the turbocharger to a second air pressure, forming a second pressure air stream, which is partly cooled in the main heat exchanger and is led to an expansion turbine, after expansion depressurization, to the rectification column system,
Said second portion of the first pressure air stream is fed to said rectification column system after having been fully cooled in the main heat exchanger and further depressurized,
Obtaining a liquid product in the air separation plant, the liquid production ratio of the air separation plant ranging from 20% to 30%,
Obtaining a liquid first product stream in the rectifying column system, which first product stream is raised in liquid state to a higher first product pressure, is heat exchanged with a second part of the first pressure air stream in the main heat exchanger, is removed as a first pressure gas product from the air separation plant after evaporation or pseudo-evaporation and recuperation,
Wherein,
The air separation plant does not comprise an air booster driven by externally supplied energy.
2. A method of cryogenically separating air according to claim 1 wherein the first air pressure ranges from 12bara to 17bara and the second air pressure ranges from 17bara to 25bara.
3. The method of cryogenically separating air according to claim 2 wherein the first product stream comprises liquid oxygen and the first product pressure is no greater than 6bara.
4. A method of cryogenically separating air as claimed in claim 3 wherein the first product pressure is not greater than 4.5bara.
5. The method of cryogenic air separation of claim 1, wherein the liquid product comprises one or more of liquid oxygen, liquid nitrogen, or liquid argon.
6. A cryogenic air separation plant comprising:
the primary heat exchanger is a heat exchanger,
A rectification column system having a higher pressure column and a lower pressure column,
A main air compressor for compressing all feed air to a first air pressure and forming a first pressure air stream, said first air pressure being at least 6bara higher than the operating pressure of said higher pressure column,
A single turbocharger driven by the expansion turbine for compressing a first portion of said first pressure air stream to a second air pressure and forming a second pressure air stream,
A single expansion turbine for receiving the second pressure air stream after partial cooling in the main heat exchanger,
Means for introducing a second portion of the first pressure air stream into the main heat exchanger, after complete cooling, throttling depressurization into the rectification column system,
Means for introducing the expanded depressurized second pressure air stream into the rectification column system,
Means for elevating the liquid first product stream obtained in the rectification column system to a higher first product pressure,
Means for exchanging heat in said main heat exchanger with a second portion of the first pressure air stream, a liquid first product stream at a first product pressure, and removing from said air separation plant a first pressure gas product formed after evaporation or pseudo-evaporation and recuperation,
Means for removing liquid product obtained in the rectification column system from the air separation plant, the value of the liquid production ratio of the air separation plant being in the interval 20% -30%,
Wherein,
The air separation plant does not comprise an externally supplied energy driven air supercharger.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410718297.9A CN118532889A (en) | 2024-06-04 | 2024-06-04 | Cryogenic air separation plant and method for cryogenically separating air |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410718297.9A CN118532889A (en) | 2024-06-04 | 2024-06-04 | Cryogenic air separation plant and method for cryogenically separating air |
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