Backup nitrogen system and air separation unit sealing gas system

Abstract

The utility model discloses a backup nitrogen system and an air separation unit sealing gas system, and relates to the technical field of air separation, the backup nitrogen system comprises a liquid nitrogen storage tank, a gasifier, a buffer tank, an instrument gas main pipeline, a heating gas main pipeline, a first pipeline bridging assembly and a second pipeline bridging assembly; the gasifier is communicated with the liquid nitrogen storage tank; the buffer tank is communicated with the gasifier; the buffer tank is communicated with an instrument gas main pipeline; the first pipeline bridging assembly comprises a first pipeline bridging pipe and a first pipeline bridging valve, and the first pipeline bridging pipe is communicated with an instrument gas main pipeline and a heating gas main pipeline; the second pipeline crossover assembly comprises a second pipeline crossover pipe and a second pipeline crossover valve, one end of the second pipeline crossover pipe is communicated with the heating gas main pipeline, and the other end of the second pipeline crossover pipe is communicated with a liquid oxygen pump sealing gas pipeline and an expansion machine sealing gas pipeline; according to the technical scheme provided by the utility model, stable sealing gas can be provided for the air separation device.

Description

Technical Field

[0001] The utility model relates to the technical field of air separation, in particular to a backup nitrogen system and a sealing gas system for an air separation device. Background Art

[0002] The air separation unit is a set of industrial equipment used to separate the various gas components in the air and produce oxygen, nitrogen, argon and other gases of the air components. In the air separation unit, the sealing gas is very important. In the relevant technology, the sealing gas of the air separation unit is provided by a molecular sieve through a pipeline. However, during the startup process of the air separation unit, the sealing gas provided by the molecular sieve will have insufficient pressure, which may cause problems such as poor sealing and leakage of cryogenic liquid. Utility Model Content

[0003] The main purpose of the utility model is to provide a backup nitrogen system and an air separation device sealing gas system, aiming at providing stable sealing gas for a liquid oxygen pump and an expander of the air separation device.

[0004] To achieve the above purpose, the backup nitrogen system proposed by the utility model includes:

[0005] Liquid nitrogen storage tanks;

[0006] A vaporizer, wherein an input end of the vaporizer is connected to an output end of the liquid nitrogen storage tank through a pipeline;

[0007] A buffer tank, wherein an input end of the buffer tank is connected to an output end of the gasifier through a pipeline;

[0008] An instrument gas main pipeline, the instrument gas main pipeline is used to communicate with the instrument gas outlet of the molecular sieve of the air separation device, and the output end of the buffer tank is connected to the instrument gas main pipeline;

[0009] A heating gas main pipeline, the heating gas main pipeline is used to communicate with the heating gas outlet of the molecular sieve of the air separation device;

[0010] a first pipeline jumper assembly, the first pipeline jumper assembly comprising a first pipeline jumper tube and a first pipeline jumper valve, the first pipeline jumper tube is used to connect the instrument gas main pipeline and the heating gas main pipeline, and the first pipeline jumper valve is arranged on the first pipeline jumper tube; and

[0011] A second pipeline jumper assembly, the second pipeline jumper assembly includes a second pipeline jumper tube and a second pipeline jumper valve, the second pipeline jumper valve is arranged on the second pipeline jumper tube, one end of the second pipeline jumper tube is connected to the heating gas main pipeline, and the other end of the second pipeline jumper tube is used to connect the liquid oxygen pump sealing gas pipeline and the expander sealing gas pipeline of the air separation unit.

[0012] In one embodiment, the backup nitrogen system further comprises a bypass manual valve, and the bypass manual valve is arranged at one end of the heating gas main pipeline close to the molecular sieve of the air separation unit.

[0013] In one embodiment, the backup nitrogen system further includes a booster valve, and the booster valve is disposed at the output end of the liquid nitrogen storage tank.

[0014] In one embodiment, the backup nitrogen system further comprises a first safety valve, which is arranged on a pipeline between the liquid nitrogen storage tank and the vaporizer; and / or

[0015] The backup nitrogen system further includes a first discharge valve, which is arranged on a pipeline between the liquid nitrogen storage tank and the vaporizer.

[0016] In one embodiment, the backup nitrogen system further comprises a heater, an input end of the heater is connected to an output end of the gasifier via a pipeline, and an output end of the heater is connected to an input end of the buffer tank via a pipeline.

[0017] In one embodiment, the backup nitrogen system further comprises a second safety valve, which is disposed on a pipeline between the heater and the buffer tank; and / or

[0018] The backup nitrogen system further includes a second discharge valve, which is disposed on a pipeline between the heater and the buffer tank.

[0019] In one embodiment, the backup nitrogen system further includes a self-operated pressure reducing valve, and the self-operated pressure reducing valve is disposed at the input end of the buffer tank.

[0020] In one embodiment, the vaporizer is an air bath vaporizer.

[0021] In one embodiment, the backup nitrogen system further includes a remote pressure gauge, and the remote pressure gauge is arranged on the instrument gas main pipeline.

[0022] The utility model also provides a sealing gas system for an air separation device, wherein the sealing gas system for the air separation device comprises the backup nitrogen system as described above.

[0023] In the technical solution of the utility model, the liquid nitrogen in the liquid nitrogen storage tank is converted into nitrogen after passing through the vaporizer, and is buffered in the buffer tank to provide stable nitrogen to the instrument gas main pipeline. During the startup of the air separation unit, by opening the first pipeline jumper valve and the second pipeline jumper valve, the nitrogen discharged from the buffer tank can flow from the instrument gas main pipeline to the heating gas main pipeline, and then flow to the liquid oxygen pump sealing gas pipeline and the expander sealing gas pipeline, thereby providing stable sealing gas for the liquid oxygen pump and the expander of the air separation unit, ensuring the normal operation of the expander and good sealing of the liquid oxygen pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of an embodiment of a backup nitrogen system provided by the utility model;

[0026] Figure 2 This is the connection diagram of the instrument gas main pipeline;

[0027] Figure 3 This is a connection diagram for the heating gas main pipeline.

[0028] Description of Figure Numbers:

[0029] 100. Backup nitrogen system; 1. Liquid nitrogen storage tank; 2. Vaporizer; 3. Buffer tank; 4. Instrument gas main pipeline; 5. Heating gas main pipeline; 6. First pipeline jumper valve; 7. Second pipeline jumper valve; 8. Bypass hand valve; 9. Pressurization; 10. First safety valve; 11. First discharge valve; 12. Heater; 13. Second safety valve; 14. Second discharge valve; 15. Self-operated pressure reducing valve; 16. Remote pressure gauge; 17. Expander reflux valve instrument gas pipeline; 18. Expander instrument gas pipeline; 19. Liquid oxygen pump cold box instrument gas pipeline; 20. Cold box instrument gas pipeline; 21. Purification and regeneration system instrument gas pipeline; 22. Precooling system instrument gas pipeline; 23. Purification system instrument gas pipeline; 24. Compressor instrument gas pipeline; 25. Turbine auxiliary instrument gas pipeline; 26. Bypass filter instrument gas pipeline; 27. Liquid nitrogen tank area instrument gas pipeline; 28. Liquid oxygen pipe area instrument gas pipeline; 29. ​​Liquid argon tank area instrument gas pipeline; 30. Analysis room chromatograph gas pipeline; 31. Circulating oxygen pump A heating gas pipeline; 32 Circulating oxygen pump B heating gas pipeline; 33. Cryogenic expander heating gas pipeline; 34. Cryogenic expander heating gas pipeline; 35. Argon system heating gas pipeline; 36. Liquid argon tank area heating gas pipeline; 37. Liquid nitrogen tank area heating gas pipeline; 38. Liquid oxygen tank area heating gas pipeline; 39. Molecular sieve.

[0030] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0034] The utility model provides a backup nitrogen system 100 .

[0035] See also Figures 1 to 3In one embodiment of the utility model, the backup nitrogen system 100 includes a liquid nitrogen storage tank 1, a vaporizer 2, a buffer tank 3, an instrument gas main pipeline 4, a heating gas main pipeline 5, a first pipeline jumper assembly and a second pipeline jumper assembly; the input end of the vaporizer 2 is connected to the output end of the liquid nitrogen storage tank 1 through a pipeline; the input end of the buffer tank 3 is connected to the output end of the vaporizer 2 through a pipeline; the instrument gas main pipeline 4 is used to communicate with the instrument gas outlet of the molecular sieve 39 of the air separation unit, and the output end of the buffer tank 3 is connected to the instrument gas main pipeline 4; the heating gas main pipeline 5 is used to communicate with the molecular sieve 39 of the air separation unit. The heated gas outlet of the sub-sieve 39 is connected; the first pipeline jumper assembly includes a first pipeline jumper tube and a first pipeline jumper valve 6, the first pipeline jumper tube is used to connect the instrument gas main pipeline 4 and the heated gas main pipeline 5, and the first pipeline jumper valve 6 is arranged on the first pipeline jumper tube; the second pipeline jumper assembly includes a second pipeline jumper tube and a second pipeline jumper valve 7, the second pipeline jumper valve 7 is arranged on the second pipeline jumper tube, one end of the second pipeline jumper tube is connected to the heated gas main pipeline 5, and the other end of the second pipeline jumper tube is used to connect the liquid oxygen pump sealing gas pipeline and the expander sealing gas pipeline of the air separation unit.

[0036] Among them, see Figure 2 The instrument gas main pipeline 4 is connected with the pipelines of various equipments of the air separation unit, including the expander reflux valve instrument gas pipeline 17, the expander instrument gas pipeline 18, the liquid oxygen pump cold box instrument gas pipeline 19, the cold box instrument gas pipeline 20, the purification and regeneration system instrument gas pipeline 21, the precooling system instrument gas pipeline 22, the purification system instrument gas pipeline 23, the compressor instrument gas pipeline 24, the turbine auxiliary instrument gas pipeline 25, the bypass filter instrument gas pipeline 26, the liquid nitrogen tank area instrument gas pipeline 27, the liquid oxygen pipe area instrument gas pipeline 28, the liquid argon tank area instrument gas pipeline 29, the analysis room chromatograph gas pipeline 30, etc.

[0037] See also Figure 3 The heating gas main pipeline 5 is connected with the pipelines of various equipment in the air separation unit, including the heating gas pipeline of circulating oxygen pump A, the heating gas pipeline of circulating oxygen pump B, the heating gas pipeline of cryogenic expander 3334, the heating gas pipeline of cryogenic expander 3334, the heating gas pipeline of argon system 35, the heating gas pipeline of liquid argon tank area 36, ​​the heating gas pipeline of liquid nitrogen tank area 37, the heating gas pipeline of liquid oxygen tank area 38, etc.

[0038] In the technical solution of the utility model, the liquid nitrogen in the liquid nitrogen storage tank 1 is converted into nitrogen after passing through the vaporizer 2, and is buffered by the buffer tank 3 to provide stable nitrogen to the instrument gas main pipeline 4. During the startup of the air separation device, by opening the first pipeline jumper valve 6 and the second pipeline jumper valve 7, the nitrogen discharged from the buffer tank 3 can flow from the instrument gas main pipeline 4 to the heating gas main pipeline 5, and then flow to the liquid oxygen pump sealing gas pipeline and the expander sealing gas pipeline, thereby providing stable sealing gas for the liquid oxygen pump and the expander of the air separation device, ensuring the normal operation of the expander and good sealing of the liquid oxygen pump. In addition, when necessary, instrument gas and heating gas can also be provided to various equipment of the air separation device through the instrument gas main pipeline 4 and the heating gas main pipeline 5.

[0039] It is understandable that some air compressors and boosters are integrated structures. In this case, the booster will rotate with the air compressor. During the rotation, the heated gas provided by the molecular sieve 39 will maintain the positive pressure at the booster inlet. However, when the air separation unit is started, the heated gas pressure provided by the molecular sieve 39 will fluctuate. Taking this into account, in one embodiment of the present utility model, please refer to Figure 1 The backup nitrogen system 100 also includes a bypass hand valve 8, which is arranged at one end of the heating gas main pipeline 5 close to the molecular sieve 39 of the air separation unit. When the air separation unit is started, the first pipeline jumper valve 6 and the bypass hand valve 8 can be opened. At this time, the backup nitrogen system 100 replenishes air to the booster inlet to avoid the booster vacuum accident, and also to avoid excessive fluctuations in the air flow passing through the molecular sieve 39, resulting in the molecular sieve 39 carrying water accident.

[0040] Further, in an embodiment of the present utility model, please refer to Figure 1 The backup nitrogen system 100 further includes a booster valve 9, which is disposed at the output end of the liquid nitrogen storage tank 1. After the liquid nitrogen flows out, it is pressurized by the booster valve 9 and then enters the vaporizer 2 to become nitrogen, so as to ensure the pressure of the liquid nitrogen entering the vaporizer 2. The pipeline between the liquid nitrogen storage tank 1 and the vaporizer 2 is provided with a tank outlet valve for controlling the circulation of the liquid nitrogen.

[0041] Furthermore, in an embodiment of the present invention, please refer to Figure 1 The backup nitrogen system 100 further includes a first safety valve 10, which is disposed on the pipeline between the liquid nitrogen storage tank 1 and the vaporizer 2; the backup nitrogen system 100 further includes a first discharge valve 11, which is disposed on the pipeline between the liquid nitrogen storage tank 1 and the vaporizer 2. The first safety valve 10 and the first discharge valve 11 can protect the pipeline, thereby improving the safety of the backup nitrogen system 100 during use.

[0042] In order to meet the use requirements, in one embodiment of the present utility model, please refer to Figure 1The backup nitrogen system 100 also includes a heater 12. The input end of the heater 12 is connected to the output end of the vaporizer 2 through a pipeline. The output end of the heater 12 is connected to the input end of the buffer tank 3 through a pipeline. The nitrogen discharged from the vaporizer 2 is heated by the heater 12 to prevent the nitrogen temperature flowing into the instrument gas main pipeline 4 from being too low and unable to be used normally.

[0043] Further, in an embodiment of the present utility model, please refer to Figure 1 The backup nitrogen system 100 further includes a second safety valve 13, which is disposed on the pipeline between the heater 12 and the buffer tank 3; the backup nitrogen system 100 further includes a second discharge valve 14, which is disposed on the pipeline between the heater 12 and the buffer tank 3. The second safety valve 13 and the second discharge valve 14 can protect the pipeline, thereby improving the safety of the backup nitrogen system 100 during use.

[0044] Specifically, in one embodiment of the present invention, please refer to Figure 1 The backup nitrogen system 100 also includes a self-operated pressure reducing valve 15, which is arranged at the input end of the buffer tank 3. Increasing the self-operated pressure reducing valve 15 can adjust the outlet pressure of the buffer tank 3 to make it slightly lower than the pressure of the instrument gas provided by the molecular sieve 39. In this way, when the molecular sieve 39 can normally supply the instrument gas, the nitrogen of the backup nitrogen system 100 is not sent out and is in a standby state. When the instrument gas provided by the molecular sieve 39 fluctuates, the backup nitrogen system 100 can play a role in stabilizing the pressure to ensure that the air separation unit can operate normally.

[0045] Furthermore, in one embodiment of the present invention, the vaporizer 2 is an air bath vaporizer 2, and in other embodiments of the present invention, the vaporizer 2 may be a steam heating vaporizer 2, a hot water bath vaporizer 2, a forced ventilation vaporizer 2, an electric heating vaporizer 2, or a solid heat conduction vaporizer 2, etc.

[0046] Specifically, in one embodiment of the present invention, please refer to Figure 1 The backup nitrogen system 100 also includes a remote pressure gauge 16, which is arranged on the instrument gas main pipeline 4. The remote pressure gauge 16 can detect the pressure of the instrument gas main pipeline 4 and transmit corresponding information, so as to find problems in time.

[0047] The utility model also proposes a sealing gas system for an air separation device, which includes the above-mentioned backup nitrogen system 100. The specific structure of the backup nitrogen system 100 refers to the above-mentioned embodiment. Since the sealing gas system of the air separation device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0048] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A backup nitrogen system for an air separation unit, characterized in that: include: Liquid nitrogen storage tanks; A vaporizer, wherein an input end of the vaporizer is connected to an output end of the liquid nitrogen storage tank through a pipeline; A buffer tank, wherein an input end of the buffer tank is connected to an output end of the gasifier through a pipeline; An instrument gas main pipeline, the instrument gas main pipeline is used to communicate with the instrument gas outlet of the molecular sieve of the air separation device, and the output end of the buffer tank is connected to the instrument gas main pipeline; A heating gas main pipeline, the heating gas main pipeline is used to communicate with the heating gas outlet of the molecular sieve of the air separation device; A first pipeline jumper assembly, the first pipeline jumper assembly comprising a first pipeline jumper tube and a first pipeline jumper valve, the first pipeline jumper tube is used to connect the instrument gas main pipeline and the heating gas main pipeline, and the first pipeline jumper valve is arranged on the first pipeline jumper tube; as well as A second pipeline jumper assembly, the second pipeline jumper assembly includes a second pipeline jumper tube and a second pipeline jumper valve, the second pipeline jumper valve is arranged on the second pipeline jumper tube, one end of the second pipeline jumper tube is connected to the heating gas main pipeline, and the other end of the second pipeline jumper tube is used to connect the liquid oxygen pump sealing gas pipeline and the expander sealing gas pipeline of the air separation unit.

2. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system also includes a bypass hand valve, which is arranged at one end of the heating gas main pipeline close to the molecular sieve of the air separation device.

3. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system also includes a booster valve, which is arranged at the output end of the liquid nitrogen storage tank.

4. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system further comprises a first safety valve, which is arranged on a pipeline between the liquid nitrogen storage tank and the vaporizer; and / or The backup nitrogen system further includes a first discharge valve, which is arranged on a pipeline between the liquid nitrogen storage tank and the vaporizer.

5. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system further includes a heater, an input end of the heater is connected to an output end of the gasifier through a pipeline, and an output end of the heater is connected to an input end of the buffer tank through a pipeline.

6. The nitrogen backup system according to claim 5, characterized in that: The backup nitrogen system further comprises a second safety valve, which is arranged on a pipeline between the heater and the buffer tank; and / or The backup nitrogen system further includes a second discharge valve, which is disposed on a pipeline between the heater and the buffer tank.

7. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system also includes a self-operated pressure reducing valve, which is arranged at the input end of the buffer tank.

8. The nitrogen backup system according to claim 1, characterized in that: The gasifier is an air bath type gasifier.

9. The nitrogen backup system according to claim 1, characterized in that: The backup nitrogen system also includes a remote pressure gauge, which is arranged on the instrument gas main pipeline.

10. A sealing gas system for an air separation unit, characterized in that: The air separation unit sealing gas system comprises the backup nitrogen system according to any one of claims 1 to 9.

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