Cooling box heating system of air separation device

Abstract

The utility model relates to the technical field of air separation devices, in particular to an air separation device cold box heating system which comprises a first air compressor, a first air separation device and a second air separation device, and the first air compressor is respectively connected with the air inlet end of the first air separation device and the air inlet end of the second air separation device through compressed air supply pipes. The two air separation devices are communicated with the first air compressor through the compressed air supply pipe, so that when the air separation device cold box is heated, the air compressor corresponding to one air separation device is closed, and the compressor corresponding to the other air separation device works according to the lowest power; compressed air provided by the first air compressor is provided for the first air separation device and the second air separation device respectively, so that waste caused by emptying of the compressed air is avoided, the working number of the air compressors can be reduced, resource consumption is further reduced, production efficiency is improved, and the service life of the air compressors is guaranteed. And the actual heating requirement of the cold box of the air separation device is met.

Description

Technical Field

[0001] The utility model relates to the technical field of air separation devices, in particular to a cold box heating system for an air separation device. Background Art

[0002] The air separation unit is mainly used to liquefy oxygen and nitrogen in the air through low temperature, and then separate and collect them according to the distillation temperature; due to the presence of various impurities and other gases in the air, the temperature needs to be lowered to -170℃~-190℃ to separate oxygen and nitrogen. Therefore, in actual work, the cold box of the equipment needs to be regularly heated to about -100℃ and then inspected.

[0003] For example, the Chinese invention patent application with application number 202010896752.6 records that after a long period of operation of a cryogenic air separation unit, the cryogenic equipment and fluid pipelines of the distillation system may gradually increase resistance due to the internal deposition of ice, dry ice or mechanical powder (all of which are blocking components). Therefore, after the air separation unit has been in operation for a period of time, the distillation system should be heated and purged to remove these blocking components.

[0004] However, when the air separation unit heats the cold box, the air compressor needs to run continuously to compress the external air and provide it to the air separation unit. When the air compressor runs at the lowest power, too much air will be provided to the air separation unit, causing most of the air to be discharged, thereby wasting resources.

[0005] However, reducing the power of the air compressor so that its air supply meets the heating needs of the cold box will reduce the service life of the air compressor and increase production costs. Utility Model Content

[0006] The utility model aims to provide a cold box heating system for an air separation device, so as to solve the technical problem that the air compressor causes waste of air supply when heating the cold box of the air separation device.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] An air separation unit cold box heating system comprises a first air compressor, a first air separation unit and a second air separation unit, wherein the first air compressor is connected to the air inlet end of the first air separation unit and the air inlet end of the second air separation unit through a compressed air supply pipe.

[0009] It is further defined that a heating switch valve is provided on the compressed air supply pipe.

[0010] It is further defined that the heating switch valve includes a blind plate valve, and the blind plate valve is located between the first air separation device and the second air separation device.

[0011] It is further defined that the heating switch valve also includes a first stop valve, and the first stop valve is located between the blind plate valve and the first air separation device.

[0012] It is further defined that the heating switch valve also includes a second stop valve, and the second stop valve is located between the blind plate valve and the second air separation device.

[0013] It is further defined that a first pressure relief unit is also provided on the compressed air supply pipe, and the first pressure relief unit is connected between the first stop valve and the blind plate valve.

[0014] It is further defined that a second pressure relief unit is also provided on the compressed air supply pipe, and the second pressure relief unit is connected between the second stop valve and the blind plate valve.

[0015] It is further defined that the blind plate valve is an 8-shaped blind plate.

[0016] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0017] 1. The utility model connects two air separation units with the first air compressor through a compressed air supply pipe, so that when heating the cold box of the air separation unit, the air compressor corresponding to one air separation unit is turned off, and the compressor corresponding to the other air separation unit can work at the lowest power, and the compressed air provided by the first air compressor is respectively provided to the first air separation unit and the second air separation unit, so as to avoid the waste caused by venting the compressed air, and can also reduce the number of air compressors working, further reduce the consumption of resources, improve production efficiency, ensure the service life of the air compressor, meet the actual air separation unit cold box heating requirements, simple structure, low cost, and significant effect.

[0018] 2. The utility model provides a blind plate valve on the compressed air supply pipe so that when the first air separation unit and the second air separation unit are in working state, the compressed air supply pipe is closed to ensure that the compressed air input by the first air separation unit and the second air separation unit meets the demand.

[0019] 3. The utility model can ensure that the compressed air supply pipe is closed reliably and avoid air leakage by arranging the first stop valve and the second stop valve on the compressed air supply pipe.

[0020] 4. The utility model arranges a first pressure relief unit and a second pressure relief unit on the compressed air supply pipe, so as to discharge the remaining compressed air in the pipe between the first stop valve and the blind plate valve and between the second stop valve and the blind plate valve in time after the compressed air supply pipe is closed, and purge the pipe to avoid long-term local pressure in the pipe, thereby ensuring the service life of the compressed air supply pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a schematic diagram of the cold box heating system of the air separation unit of the utility model;

[0022] In the figure: 1-first air compressor; 2-second air compressor; 3-first air separation device; 4-second air separation device; 5-compressed air supply pipe; 6-blind plate valve; 7-first stop valve; 8-second stop valve; a-first pressure relief unit; b-second pressure relief unit. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only part of the embodiments of the present utility model, not all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present utility model.

[0024] During factory production, a phase I air separation system and a phase II air separation system are usually set up to obtain materials required for production, such as nitrogen and oxygen. Each phase air separation system includes at least two air separation units. The phase I air separation system is the same as the phase II air separation system. The two air separation units of the same period can operate and be maintained at the same time, so the phase I air separation system is taken as an example for explanation.

[0025] The first phase air separation system includes a first air separation device 3 and a second air separation device 4. The first air separation device 3 is supplied with air through a first air compressor 1, and the second air separation device 4 is supplied with air through a second air compressor 2.

[0026] Example 1

[0027] refer to Figure 1 This embodiment provides an air separation unit cold box heating system, including a first air compressor 1, a first air separation unit 3 and a second air separation unit 4, wherein the output end of the first air compressor 1 is connected to the first air separation unit 3 and the second air separation unit 4 through a compressed air supply pipe 5.

[0028] That is, an air compressor of the existing air separation system is used to provide compressed air for two air separation units when the cold box is heated. By adding a compressed air supply pipe 5, it is avoided that a single air compressor provides compressed air for one air separation unit, which will increase the power consumption of the compressor and require the additional compressed air to be emptied, resulting in a waste of resources. In order to avoid the waste of resources, it is also possible to choose to reduce the working power of the air compressor so that the working power of the air compressor is less than the minimum power, causing the air compressor to malfunction, affecting the service life, and increasing the maintenance and repair costs. Therefore, the air supply demand when the cold box of the air separation unit is heated and repaired is met, and at the same time, the power consumption of an air compressor can be reduced, the cost can be reduced, and the service life of the air compressor can be increased.

[0029] The compressed air supply pipe 5 can be selected as a DN350 carbon steel pipe. The DN350 carbon steel pipe is selected according to the actual compressed air supply demand. For example, the air supply volume is 50000Nm 3 / h, DN350 carbon steel pipe can be selected as DN500 carbon steel pipe.

[0030] At the same time, the transformation is easy and the effect is significant, making it suitable for promotion and use.

[0031] To further explain, a heating switch valve is provided on the compressed air supply pipe 5. By providing the heating switch valve on the compressed air supply pipe 5, it is possible to prevent the compressed air output by the air compressor from being input into another air separation device through the compressed air supply pipe 5 when the air separation system is working normally, thereby ensuring stable and reliable operation.

[0032] Specifically, the heating switch valve includes a blind plate valve 6, and the blind plate valve 6 can be selected as an 8-shaped blind plate, which is easy to operate and has a simple structure and low cost.

[0033] Further explanation, the heating switch valve also includes a first stop valve 7, which is arranged between the blind plate valve 6 and the first air separation device 3, so as to prevent the compressed air from flowing to the second air separation device 4 during normal operation of the first air separation device 3 and the first air compressor 1, or the compressed air from flowing to the first air separation device 3 during normal operation of the second air separation device 4 and the second air compressor 2, so the first stop valve 7 is arranged to increase the blocking effect.

[0034] Further explanation, the heating switch valve also includes a second stop valve 8. By setting the second stop valve 8, it can serve as a blocking guarantee when the first stop valve 7 or the blind plate valve 6 fails; at the same time, the second stop valve 8 can also cooperate with the first stop valve 7 to block the compressed air output by the first air compressor 1 and the second air compressor 2 when the blind plate valve 6 fails, so that the maintenance and replacement of the blind plate valve 6 can be completed without stopping the machine, thereby ensuring production efficiency.

[0035] To further explain, in order to avoid residual compressed air in the compressed air supply pipe 5 after the air separation unit cold box is heated, or to exhaust the compressed air in the compressed air supply pipe 5 when the blind plate valve 6 is repaired or replaced, a first pressure relief unit a and a second pressure relief unit b are selected to be arranged on the compressed air supply pipe 5.

[0036] The first pressure relief unit a is arranged between the first stop valve 7 and the blind plate valve 6 , and the second pressure relief unit b is arranged between the blind plate valve 6 and the second stop valve 8 .

[0037] The first pressure relief unit a and the second pressure relief unit b both include a pressure relief pipe and a pressure relief valve arranged on the pressure relief pipe. When the cold box of the air separation unit is heated, the two pressure relief valves are in a closed state. After the heating of the cold box of the air separation unit is completed and normal work is performed, the first stop valve 7 and the second stop valve 8 are closed, and then the blind plate valve 6 is closed. Subsequently, the two pressure relief valves are opened to discharge the remaining compressed air in the compressed air supply pipe 5 through the pressure relief pipe, thereby avoiding pressure in the compressed air supply pipe 5, increasing its service life, and meeting actual use requirements.

[0038] Obviously, the embodiments described above are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cold box heating system for an air separation unit, characterized in that: The invention comprises a first air compressor (1), a first air separation device (3) and a second air separation device (4); the first air compressor (1) is connected to the air inlet end of the first air separation device (3) and the air inlet end of the second air separation device (4) respectively through a compressed air supply pipe (5).

2. The cold box heating system of the air separation unit according to claim 1, characterized in that: The compressed air supply pipe (5) is provided with a heating switch valve.

3. The cold box heating system of the air separation unit according to claim 2, characterized in that: The heating switch valve comprises a blind plate valve (6), and the blind plate valve (6) is located between the first air separation device (3) and the second air separation device (4).

4. The cold box heating system of the air separation unit according to claim 3, characterized in that: The heating switch valve further comprises a first stop valve (7), wherein the first stop valve (7) is located between the blind plate valve (6) and the first air separation device (3).

5. The cold box heating system for an air separation unit according to claim 4, characterized in that: The heating switch valve further comprises a second stop valve (8), wherein the second stop valve (8) is located between the blind plate valve (6) and the second air separation device (4).

6. The cold box heating system of the air separation unit according to claim 5, characterized in that: The compressed air supply pipe (5) is also provided with a first pressure relief unit (a), and the first pressure relief unit (a) is connected between the first stop valve (7) and the blind plate valve (6).

7. The cold box heating system of the air separation unit according to claim 6, characterized in that: The compressed air supply pipe (5) is also provided with a second pressure relief unit (b), and the second pressure relief unit (b) is connected between the second stop valve (8) and the blind plate valve (6).

8. The cold box heating system for an air separation unit according to claim 6, characterized in that: The blind plate valve (6) is an 8-shaped blind plate.

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