Air separation cold box system

Abstract

The invention relates to the technical field of air separation, in particular to a cold box system for air separation, the cold box system for air separation comprises a first oxygen tower, a second oxygen tower, a first nitrogen tower and a second nitrogen tower, in the cold box system for air separation, the first nitrogen tower and the second nitrogen tower are arranged in a spaced mode; the first oxygen tower and the second oxygen tower are arranged at an interval, and the tops of the first oxygen tower and the first nitrogen tower are indirectly spliced together. A traditional oxygen tower is replaced by the first oxygen tower and the second oxygen tower which are low in height, and a traditional nitrogen tower is replaced by the first nitrogen tower and the second nitrogen tower which are low in height, so that the problems that a traditional air separation cold box system only comprises a single nitrogen tower and a single oxygen tower, so that the heights of the nitrogen tower and the oxygen tower are high, and the cost is low are solved. And after the nitrogen tower and the oxygen tower are spliced in the vertical direction, the expected height limiting requirement of a user cannot be met.

Description

Technical Field

[0001] The present application relates to the technical field of air separation, and in particular to a cold box system for air separation. Background Art

[0002] In the process of air separation using deep freezing, the low-temperature separation system is arranged in an insulated box, generally called a cold box. It is the highest system in the entire air separation unit and is also the core iconic system of the air separation unit. Some users have strict restrictions on the height of the air separation system due to policy requirements or other special needs of the unit construction site. For example, due to the need for aircraft flight near the airport, the government has strict height restrictions on all nearby buildings. For example, in cold places near the Arctic, users consider the impact of wind load, snow load and the convenience of operation and inspection under extremely low temperatures, and hope to place the air separation cold box inside the plant. However, the excessive height of the cold box will inevitably greatly increase the cost of plant construction, and many users have an urgent need for an air separation unit to produce diversified products (such as low-purity oxygen, oxygen, crude krypton xenon, nitrogen, high-purity nitrogen and other products).

[0003] The traditional air separation cold box system only includes a single nitrogen tower and a single oxygen tower, which results in the nitrogen tower and the oxygen tower being relatively high. When the nitrogen tower and the oxygen tower are vertically spliced, they cannot meet the height limit requirements expected by users. Summary of the invention

[0004] The present application provides an air separation cold box system, which aims to solve the problem that the traditional air separation cold box system only includes a single nitrogen tower and a single oxygen tower, resulting in the nitrogen tower and the oxygen tower being relatively high in height, and when the nitrogen tower and the oxygen tower are spliced ​​in the vertical direction, they cannot meet the height limit requirements expected by the user.

[0005] In order to solve the above technical problems, the present application proposes an air separation cold box system, the air separation cold box system comprises: a first oxygen tower, a second oxygen tower, a first nitrogen tower, and a second nitrogen tower; The first nitrogen tower and the second nitrogen tower are spaced apart, the first oxygen tower and the second oxygen tower are spaced apart, the first oxygen tower is connected to the second oxygen tower, the first nitrogen tower is connected to the second nitrogen tower, and the first oxygen tower is indirectly spliced ​​together with the top of the first nitrogen tower.

[0006] Furthermore, the air separation cold box system also includes a condenser, and the condenser is spliced ​​on the top of the second nitrogen tower.

[0007] Furthermore, the air separation cold box system also includes a condenser evaporator, and the condenser evaporator is spliced ​​between the first nitrogen tower and the first oxygen tower.

[0008] Furthermore, the air separation cold box system also includes a krypton-xenon tower and an evaporator, and the krypton-xenon tower is spliced ​​with the evaporator.

[0009] Furthermore, the top of the first nitrogen tower is connected to the bottom of the second nitrogen tower.

[0010] Furthermore, the air separation cold box system also includes a first heat exchanger, and the first heat exchanger is connected to the condenser evaporator, the second oxygen tower, the first nitrogen tower and the condenser.

[0011] Furthermore, the top of the first oxygen tower is connected to the bottom of the second oxygen tower.

[0012] Furthermore, the bottom of the first oxygen tower is connected to the top of the krypton-xenon tower.

[0013] Furthermore, the air separation cold box system also includes a second heat exchanger, and the second heat exchanger is connected to the condenser, the second nitrogen tower and the second oxygen tower.

[0014] Furthermore, the air separation cold box system also includes a liquid oxygen pump, and the liquid oxygen pump is connected to the first oxygen tower, the second oxygen tower and the condenser.

[0015] The beneficial effects of the present application are as follows: in the cold box system for air separation provided in the present application, the first nitrogen tower and the second nitrogen tower are arranged at intervals, the first oxygen tower and the second oxygen tower are arranged at intervals, the first oxygen tower is connected to the second oxygen tower, the first nitrogen tower is connected to the second nitrogen tower, and the top of the first oxygen tower and the first nitrogen tower are indirectly spliced ​​together. By setting the first oxygen tower and the second oxygen tower instead of the traditional single oxygen tower, and by setting the first nitrogen tower and the second nitrogen tower instead of the traditional single nitrogen tower, the heights of the first oxygen tower, the second oxygen tower, the first nitrogen tower, and the second nitrogen tower can be effectively shortened, so that the first oxygen tower and the first nitrogen tower can meet the height limit requirements of the user after being spliced ​​together. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them: Figure 1 is a schematic diagram of an air separation cold box system according to an embodiment of the present invention; Figure 2It is a process flow chart of an air separation cold box system according to an embodiment of the present invention.

[0017] Explanation of reference numerals: 1. first low-purity oxygen product; 2. second oxygen product; 3. first nitrogen product; 4. second high-purity nitrogen product; 5. liquid oxygen product; 6. first high-purity liquid nitrogen product; 7. crude krypton-xenon liquid product; 10. first oxygen tower; 20. second oxygen tower; 30. first nitrogen tower; 40. second nitrogen tower; 50. condenser; 60. condenser-evaporator; 70. krypton-xenon tower; 80. evaporator; 90. first heat exchanger; 91. second heat exchanger; 92. liquid oxygen pump; 100. first raw air; 110. second raw air; 201. first nitrogen; 202. second nitrogen; 203. third nitrogen; 211. first First liquid nitrogen; 212, second liquid nitrogen; 220, oxygen-rich liquid; 301, first high-purity nitrogen; 302, second high-purity nitrogen; 311, first high-purity liquid nitrogen; 312, second high-purity liquid nitrogen; 320, third liquid nitrogen; 401, first low-purity oxygen; 402, second low-purity oxygen; 411, first liquid oxygen; 412, second liquid oxygen; 500, low-purity liquid oxygen; 501, first part of low-purity liquid oxygen; 503, second part of low-purity liquid oxygen; 511, first waste gas; 512, second waste gas; 513, combined waste gas; 600, krypton-xenon liquid; 610, oxygen product; 3000, high-purity nitrogen system; 6000, crude krypton-xenon system. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "a", "an", "above", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of features, integers, steps, operations, elements, modules, modules and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, modules, modules, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein includes all or any module and all combinations of one or more associated listed items.

[0020] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0021] like Figure 1 As shown, the present application provides an air separation cold box system, which includes a first oxygen tower 10, a second oxygen tower 20, a first nitrogen tower 30, and a second nitrogen tower 40. The first nitrogen tower 30 and the second nitrogen tower 40 are arranged at intervals, the first oxygen tower 10 and the second oxygen tower 20 are arranged at intervals, the first oxygen tower 10 is connected to the second oxygen tower 20, the first nitrogen tower 30 is connected to the second nitrogen tower 40, and the tops of the first oxygen tower 10 and the first nitrogen tower 30 are indirectly spliced ​​together.

[0022] In a specific embodiment, the first oxygen tower 10 and the second oxygen tower 20 are the main equipment for separating oxygen in the air, and they can gradually purify and separate the oxygen in the air through a specific process. The first nitrogen tower 30 and the second nitrogen tower 40 are mainly used to separate nitrogen in the air. Since the first oxygen tower 10 is connected to the second oxygen tower 20, and the first nitrogen tower 30 is connected to the second nitrogen tower 40, the material can flow between the first oxygen tower 10 and the second oxygen tower 20, and between the first nitrogen tower 30 and the second nitrogen tower 40 to achieve further separation and purification of the product. The first oxygen tower 10 is indirectly spliced ​​with the first nitrogen tower 30 in the vertical direction, so that the first oxygen tower 10 and the first nitrogen tower 30 can quickly exchange materials and improve the separation efficiency.

[0023] In summary, by providing the first oxygen tower 10 and the second oxygen tower 20 instead of the traditional single oxygen tower, and by providing the first nitrogen tower 30 and the second nitrogen tower 40 instead of the traditional single nitrogen tower, the heights of the first oxygen tower 10, the second oxygen tower 20, the first nitrogen tower 30, and the second nitrogen tower 40 can be effectively shortened, so that the height limit requirement of the user can be met after the first oxygen tower 10 and the first nitrogen tower 30 are spliced ​​together.

[0024] like Figure 1 As shown, the cold box system for air separation further includes a condenser 50 , which is spliced ​​to the top of the second nitrogen tower 40 .

[0025] In a specific embodiment, the condenser 50 is a device that plays a cooling role. In the cold box system of air separation, the condenser 50 is spliced ​​to the top of the second nitrogen tower 40, and the nitrogen separated in the second nitrogen tower 40 can be cooled to make it liquid nitrogen. In addition, the condenser 50 is spliced ​​to the top of the second nitrogen tower 40 so that the nitrogen can directly enter the condenser 50 for cooling after coming out of the second nitrogen tower 40, thereby reducing the flow resistance of the gas in the pipeline and improving the cooling efficiency.

[0026] like Figure 1 As shown, the cold box system for air separation further includes a condenser evaporator 60 , which is spliced ​​between the first nitrogen tower 30 and the first oxygen tower 10 .

[0027] In a specific embodiment, the condenser evaporator 60 is a device that can perform both condensation and evaporation. In the cold box system of air separation, the condenser evaporator 60 is spliced ​​between the first nitrogen tower 30 and the first oxygen tower 10, and heat exchange and material transfer between the first nitrogen tower 30 and the first oxygen tower 10 can be achieved. Specifically, one end of the condenser evaporator 60 is spliced ​​with the bottom of the first oxygen tower 10, and the other end of the condenser evaporator 60 is spliced ​​with the top of the first nitrogen tower 30, so that the first oxygen tower 10, the condenser evaporator 60, and the first nitrogen tower 30 are spliced ​​into a whole in sequence in the vertical direction.

[0028] like Figure 1 As shown, the top of the first nitrogen tower 30 is connected to the bottom of the second nitrogen tower 40.

[0029] In a specific embodiment, by connecting the top of the first nitrogen tower 30 with the bottom of the second nitrogen tower 40, the nitrogen generated at the top of the first nitrogen tower 30 can smoothly enter the bottom of the second nitrogen tower 40 for further purification and separation.

[0030] like Figure 1 As shown, the cold box system for air separation further includes a first heat exchanger 90 , which is connected to the condenser evaporator 60 , the second oxygen tower 20 , the first nitrogen tower 30 and the condenser 50 .

[0031] In a specific embodiment, the air separation process consumes a large amount of energy to cool and liquefy the air. The first heat exchanger 90 can recover cold and heat, improve energy utilization efficiency, and reduce energy consumption of the system. Specifically, the first heat exchanger 90 is connected to the condenser 50, the top of the second oxygen tower 20, the middle of the second oxygen tower 20, the bottom of the first nitrogen tower 30 and the condenser 50.

[0032] like Figure 1 As shown, the top of the first oxygen tower 10 is connected to the bottom of the second oxygen tower 20.

[0033] In a specific embodiment, by connecting the top of the first oxygen tower 10 with the bottom of the second oxygen tower 20, the oxygen generated at the top of the first oxygen tower 10 can smoothly enter the bottom of the second oxygen tower 20 for further purification and separation.

[0034] like Figure 1 As shown, the cold box system for air separation further includes a krypton-xenon tower 70 , which is spliced ​​with an evaporator 80 , and the first oxygen tower 10 is connected to the krypton-xenon tower 70 .

[0035] In a specific embodiment, the krypton-xenon tower 70 is spliced ​​with the top of the evaporator 80, and the top of the krypton-xenon tower 70 is connected to the bottom of the first oxygen tower 10, so that the liquid oxygen in the first oxygen tower 10 can quickly enter the krypton-xenon tower 70 for further purification and separation, and the liquid obtained at the bottom of the krypton-xenon tower 70 can efficiently enter the evaporator 80 for the next step of processing.

[0036] like Figure 1 As shown, the cold box system for air separation further includes a second heat exchanger 91 , which is connected to the condenser 50 , the second nitrogen tower 40 and the second oxygen tower 20 .

[0037] In a specific embodiment, the second heat exchanger 91 has the same function as the first heat exchanger 90. The second heat exchanger 91 is connected to the condenser 50, the second nitrogen tower 40 and the second oxygen tower 20, so as to realize heat exchange between these devices and improve the energy efficiency of the system. Specifically, the second heat exchanger 91 is connected to the condenser 50, the bottom of the second nitrogen tower 40 and the top of the second oxygen tower 20.

[0038] like Figure 2 As shown, the air separation cold box system also includes a liquid oxygen pump 92, which is connected to the first oxygen tower 10, the second oxygen tower 20 and the condenser 50.

[0039] In a specific embodiment, the liquid oxygen pump 92 is used to pressurize the liquid oxygen. Specifically, the liquid oxygen pump 92 is connected to the top of the first oxygen tower 10, the bottom of the second oxygen tower 20 and the condenser 50, so that the liquid oxygen at the bottom of the second oxygen tower 20 can enter the top of the first oxygen tower 10 and the condenser 50 respectively after being pressurized by the liquid oxygen pump 92.

[0040] like Figure 2 As shown, the products of the air separation cold box system are as follows: The first low-purity oxygen product 1 (oxygen purity ≤ 96%) is sent out after being combined from two sources: (1) From the top of the first oxygen tower 10; (2) From the top of condenser 50 (when high-purity nitrogen system 3000 is put into operation); The second oxygen product 2 (oxygen purity ≥ 99.6%) is sent out after being combined from two sources: (1) From the top of the condenser evaporator 60; (2) From the top of the krypton-xenon tower 70 (when the crude krypton-xenon system 6000 is put into operation); The first nitrogen product 3 (nitrogen purity ≥ 99%): from the top of the first nitrogen tower 30; The second high-purity nitrogen product 4 (nitrogen purity ≥ 99.999%): from the top of the second nitrogen tower 40; Liquid oxygen product 5 (oxygen purity ≥ 99.7%) is sent out after being combined from two sources: (1) From the bottom of the first oxygen tower 10 (when the crude krypton xenon system 6000 is in operation); or from the bottom of the condenser evaporator 60 (when the crude krypton xenon system 6000 is out of operation); (2) From the bottom of the condenser 50 (when the high-purity nitrogen system 3000 is put into operation and the crude krypton-xenon system 6000 is shut down); The first high-purity liquid nitrogen product 6 (nitrogen purity ≥ 99.999%): comes from the condenser evaporator 60 and is supercooled by the second heat exchanger 91; Crude krypton-xenon liquid product 7 (2000-10000 ppm KrXe): from the bottom of evaporator 80.

[0041] like Figure 2 As shown, in a specific embodiment, based on the specific structure of the cold box system for air separation, the production process of the product is as follows: The raw materials include first raw air 100 and second raw air 110 that meet the process requirements. A portion of the first raw air 100 is introduced into the bottom of the first nitrogen tower 30, and another portion is introduced into the evaporator 80 as a heat source. After the first raw air 100 in the evaporator 80 is liquefied, it enters the middle of the second oxygen tower 20. The second raw air 110 is directly introduced into the middle of the second oxygen tower 20.

[0042] After processing, the nitrogen obtained at the top of the first nitrogen tower 30 is divided into the first nitrogen 201, the second nitrogen 202 and the third nitrogen 203. The first nitrogen 201 enters the condenser evaporator 60, and the liquid nitrogen obtained after condensation is divided into the first liquid nitrogen 211 and the second liquid nitrogen 212. The first liquid nitrogen 211 refluxes into the top of the first nitrogen tower 30 and enters the circulation operation. The second liquid nitrogen 212 enters the first heat exchanger 90 for supercooling and then enters the top of the second oxygen tower 20. The second nitrogen 202 is discharged from the first nitrogen tower 30 as a product, and the third nitrogen 203 enters the bottom of the second nitrogen tower 40.

[0043] After processing, the high-purity nitrogen obtained at the top of the second nitrogen tower 40 is divided into a first high-purity nitrogen 301 and a second high-purity nitrogen 302. The second high-purity nitrogen 302 is discharged from the second nitrogen tower 40 as a product. The first high-purity nitrogen 301 enters the condenser 50. The high-purity liquid nitrogen obtained after condensation is divided into a first high-purity liquid nitrogen 311 and a second high-purity liquid nitrogen 312. The first high-purity liquid nitrogen 311 refluxes to the top of the second nitrogen tower 40 and enters a circulation operation. The second high-purity liquid nitrogen 312 enters the second heat exchanger 91 and is discharged as a product after being supercooled.

[0044] After the third nitrogen 203 enters the bottom of the second nitrogen tower 40 and is processed, the third liquid nitrogen 320 is obtained at the bottom of the second nitrogen tower 40 . The third liquid nitrogen 320 enters the second heat exchanger 91 for supercooling and then enters the top of the second oxygen tower 20 .

[0045] After the first raw air 100 is passed into the bottom of the first nitrogen tower 30 and processed, oxygen-rich liquid 220 is obtained at the bottom of the first nitrogen tower 30 . The oxygen-rich liquid 220 enters the first heat exchanger 90 for supercooling and then passes into the middle of the second oxygen tower 20 .

[0046] After processing in the second oxygen tower 20, the exhaust gas obtained at the top of the second oxygen tower 20 is divided into a first exhaust gas 511 and a second exhaust gas 512. The first exhaust gas 511 enters the first heat exchanger 90 to be reheated to a certain temperature and then recovers the cold energy. The second exhaust gas 512 enters the second heat exchanger 91 to be reheated to a certain temperature and then recovers the cold energy. The first exhaust gas 511 and the second exhaust gas 512 after recovering the cold energy are merged to form a merged exhaust gas 513 and then discharged.

[0047] After processing, the second oxygen tower 20 will also obtain low-purity liquid oxygen 500 at the bottom of the second oxygen tower 20. The low-purity liquid oxygen 500 is passed into the liquid oxygen pump 92 for pressurization, and then the first part of the low-purity liquid oxygen 501 is passed into the top of the first oxygen tower 10, and the second part of the low-purity liquid oxygen 503 is passed into the condenser 50 as a cold source.

[0048] After processing in the first oxygen tower 10, the low-purity oxygen obtained at the top of the first oxygen tower 10 is divided into first low-purity oxygen 401 and second low-purity oxygen 402. The first low-purity oxygen 401 is introduced into the bottom of the second oxygen tower 20, and the second low-purity oxygen 402 is discharged from the first oxygen tower 10 as a product.

[0049] After the first oxygen tower 10 is processed, the liquid oxygen obtained at the bottom of the first oxygen tower 10 is respectively the first liquid oxygen 411 and the second liquid oxygen 412. The first liquid oxygen 411 is discharged from the first oxygen tower 10 as a product, and the second liquid oxygen 412 enters the top of the krypton-xenon tower 70.

[0050] After processing in the krypton-xenon tower 70, an oxygen product 610 is obtained at the top of the krypton-xenon tower 70, and a third liquid oxygen is obtained at the bottom of the krypton-xenon tower 70. The third liquid oxygen is passed into the evaporator 80. After processing in the evaporator 80, a crude krypton-xenon liquid 600 is extracted at the bottom of the evaporator 80 as a product output.

[0051] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An air separation cold box system, characterized in that: include: A first oxygen tower, a second oxygen tower, a first nitrogen tower, and a second nitrogen tower; The first nitrogen tower and the second nitrogen tower are spaced apart, the first oxygen tower and the second oxygen tower are spaced apart, the first oxygen tower is connected to the second oxygen tower, the first nitrogen tower is connected to the second nitrogen tower, and the first oxygen tower is indirectly spliced ​​together with the top of the first nitrogen tower.

2. The air separation cold box system according to claim 1, characterized in that: The air separation cold box system further comprises a condenser, and the condenser is spliced ​​on the top of the second nitrogen tower.

3. The air separation cold box system according to claim 2, characterized in that: The air separation cold box system also includes a condenser evaporator, which is spliced ​​between the first nitrogen tower and the first oxygen tower.

4. The air separation cold box system according to claim 1, characterized in that: The air separation cold box system also includes a krypton-xenon tower and an evaporator, and the krypton-xenon tower is spliced ​​with the evaporator.

5. The air separation cold box system according to claim 1, characterized in that: The top of the first nitrogen tower is connected to the bottom of the second nitrogen tower.

6. The air separation cold box system according to claim 3, characterized in that: The air separation cold box system also includes a first heat exchanger, which is connected to the condenser evaporator, the second oxygen tower, the first nitrogen tower and the condenser.

7. The air separation cold box system according to claim 1, characterized in that: The top of the first oxygen tower is communicated with the bottom of the second oxygen tower.

8. The air separation cold box system according to claim 4, characterized in that: The bottom of the first oxygen tower is connected to the top of the krypton-xenon tower.

9. The air separation cold box system according to claim 2, characterized in that: The air separation cold box system also includes a second heat exchanger, which is connected to the condenser, the second nitrogen tower and the second oxygen tower.

10. The air separation cold box system according to claim 2, characterized in that: The air separation cold box system also includes a liquid oxygen pump, which is connected to the first oxygen tower, the second oxygen tower and the condenser.

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