Improved Drainage System and Method for the KO Drain Pot of a Compressor

Abstract

The present invention relates to on-site drainage transformation of the KO liquid separation tank of the compressor in an aromatic hydrocarbon plant, specifically to an improved drainage system and method for the KO liquid separation tank of the compressor, including: a KO liquid separation tank, with a first pipeline and a second pipeline respectively arranged on both sides of the KO liquid separation tank. The first pipeline is connected to the pipeline led out from the compressor circulation process system. One end of the second pipeline is connected to the KO liquid separation tank, and the other end is also connected to the pipeline led out from the compressor circulation process system; one side of the KO liquid separation tank in the same direction as the second pipeline is connected with a KO liquid separation tank liquid level gauge through a pipeline; a drainage pipeline is arranged at the bottom of the KO liquid separation tank, and the outlet of the drainage pipeline is connected to a buffer tank system. The buffer tank system is connected to a nitrogen system, the top of the buffer tank system is connected to a flare system through a pipeline, and the bottom of the buffer tank is connected to a reformed oil rectification tower system; the open drainage is changed to closed drainage, and the drained liquid is discharged to the reformed oil rectification tower for recycling again, so as to achieve the purpose of safety, environmental protection and energy conservation.

Description

Technical Field

[0001] The present invention relates to on-site drainage transformation of the KO liquid separation tank of a compressor in an aromatic hydrocarbon plant, specifically to an improved drainage system and method for the KO liquid separation tank of a compressor. Background Art

[0002] The KO liquid separation tank is a liquid separation device for the first-stage seal gas of the compressor. The first-stage seal gas comes from the compressor recycle process gas and contains hydrogen and a small amount of C5+. Therefore, the KO liquid separation tank plays a role in removing the C5+ heavy components.

[0003] Currently, for on-site drainage of the KO liquid separation tank of a compressor in an aromatic hydrocarbon plant, when the liquid level in the KO liquid separation tank is full, it is drained through the on-site drain and collected in a bucket, which poses a safety risk. Summary of the Invention

[0004] In view of the above technical problems, through reasonable transformation of the drainage process, the present invention provides an improved drainage system and method for the KO liquid separation tank of a compressor, changing the open drainage to closed drainage, draining the liquid to the reformed oil distillation column for recycling again, so as to achieve the purpose of safety, environmental protection and energy conservation.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: an improved drainage system for the KO liquid separation tank of a compressor, including: a KO liquid separation tank, with a first pipeline and a second pipeline respectively arranged on both sides of the KO liquid separation tank. The first pipeline is connected to the pipeline led out from the compressor recycle process system. One end of the second pipeline is connected to the KO liquid separation tank, and the other end is also connected to the pipeline led out from the compressor recycle process system; on one side of the KO liquid separation tank in the same direction as the second pipeline, a KO liquid separation tank level gauge is connected through a pipeline; a drainage pipeline is arranged at the bottom of the KO liquid separation tank, the outlet of the drainage pipeline is connected to the buffer tank system, the buffer tank system is connected to the nitrogen system, the top of the buffer tank system is connected to the flare system through a pipeline, and the bottom of the buffer tank is connected to the reformed oil distillation column system;

[0006] The process gas from the compressor recycle process system is led to the first-stage seal of the compressor through a pipeline. The process gas from the compressor recycle process system contains hydrogen and a small amount of C5+. The KO liquid separation tank is used as a liquid separation device to remove the C5+ by draining the liquid.

[0007] Further, a first valve and a second valve are respectively arranged on the first pipeline and the second pipeline. The first pipeline is connected to the lower part of one side of the KO liquid separation tank, and the second pipeline is connected to the upper part of the other side of the KO liquid separation tank;

[0008] Further, a third valve is arranged on the drainage pipeline;

[0009] Further, the buffer tank system includes: a buffer tank, a buffer tank liquid level gauge, a pressure gauge, and valves; the buffer tank is connected to the drain pipeline of the KO liquid separation tank through a third pipeline, and a fourth valve and a fifth valve are arranged on the third pipeline. A pressure gauge is arranged on the buffer tank, and a buffer tank drain pipeline is arranged at the bottom of the buffer tank. A sixth valve is arranged on the buffer tank drain pipeline; a buffer tank liquid level gauge is arranged on one side of the buffer tank in the opposite direction of the third pipeline. The top of the buffer tank is connected to the flare system through a fourth pipeline. A safety valve is arranged on the fourth pipeline, and a front valve and a rear valve are respectively arranged before and after the safety valve. The fourth pipeline is also provided with a bypass pipeline, and a seventh valve and an eighth valve are arranged on the bypass pipeline;

[0010] The accumulated liquid solvent at the bottom of the buffer tank is 3 times the full liquid level volume of the KO liquid separation tank;

[0011] The third pipeline, the buffer tank drain pipeline, the fourth pipeline, and the bypass pipeline of the fourth pipeline are all DN20, 300-pound pipelines;

[0012] The fourth valve is a one-way check valve;

[0013] The eighth valve is a ball valve;

[0014] The measuring range of the pressure gauge is 3 MPa;

[0015] The popping pressure of the safety valve is 1.8 MPa;

[0016] Further, the nitrogen system includes: a nitrogen pipeline and a three-valve group arranged on the nitrogen pipeline. The nitrogen pipeline is connected to the upper end of one side of the buffer tank in the same direction as the buffer tank liquid level gauge. The three-valve group is arranged at the inlet position of the nitrogen pipeline, and nitrogen with a pressure of 2.03 MPa is introduced into the nitrogen pipeline;

[0017] Further, the three-valve group respectively includes, from the inlet direction: a globe valve, a one-way check valve, and a ball valve. An 8-shaped blind plate is arranged between the globe valve and the one-way check valve;

[0018] Further, the reformed oil distillation column system includes: a reformed oil distillation column feed line connected to the reforming distillation column and a ninth valve arranged on the feed line. The buffer tank drain pipeline is connected to the reformed oil distillation column feed line.

[0019] Further, a drain pipeline is branched at the outlet position of the KO liquid separation tank drain pipeline, and a drain valve is arranged on the drain pipeline.

[0020] The draining method using the above draining system is as follows:

[0021] When the liquid level gauge of the compressor KO liquid separation tank shows 10% - 30%, after confirming the actual liquid level on-site, draining operation is required;

[0022] First, close the drain valve, open the safety valve, the front valve and the rear valve of the safety valve, and close the seventh valve and the eighth valve of the bypass pipeline of the fourth pipeline;

[0023] Close the three-valve group of the nitrogen pipeline, and then close the sixth valve of the drain pipeline of the buffer tank; the pressure of the KO liquid separation tank system is 1.2 Mpa;

[0024] Then, open the third valve, the fourth valve, and the fifth valve. After all the liquid in the KO liquid separation tank is drained into the buffer tank, close the third valve and the fifth valve;

[0025] The pressure of the feed line of the reformed oil distillation column is 0.4 MPa, and the pressure of the drained liquid to the buffer tank is 1 MPa. By monitoring the pressure gauge of the buffer tank and relieving the pressure to 0.5 MPa through the bypass pipeline of the fourth pipeline, then open the sixth valve of the buffer tank drain pipeline, drain the liquid onto the feed line of the reformed oil distillation column, and finally it is recycled by the reformed oil distillation column.

[0026] The above drainage method realizes safe and airtight drainage, achieving the effect of energy-saving and effective recycling.

[0027] In the described drainage method, the pressure of the drained liquid to the buffer tank is 1 MPa, which is obtained after the pressure loss when the KO liquid separation tank drains liquid to the buffer tank at 1.2 Mpa; the pressure of the KO liquid separation tank system and the pressure of the feed line of the reformed oil distillation column are both taken according to actual parameters.

[0028] The beneficial effects of the present invention are: through reasonable transformation of the drainage process, the present invention provides an improved drainage system and method for the KO liquid separation tank of the compressor, changing the open drainage to airtight drainage, draining the liquid to the reformed oil distillation column for recycling again, so as to achieve the purpose of safety, environmental protection and energy saving. Brief Description of the Drawings

[0029] Figure 1 It is a structural schematic diagram of the present invention.

[0030] In the figure, 1. KO liquid separation tank, 2. First pipeline, 3. Second pipeline, 4. KO liquid separation tank liquid level gauge, 5. KO liquid separation tank drain pipeline, 6. First valve, 7. Second valve, 8. Third valve, 9. Buffer tank, 10. Buffer tank liquid level gauge, 11. Pressure gauge, 12. Third pipeline, 13. Fourth valve, 14. Fifth valve, 15. Buffer tank drain pipeline, 16. Sixth valve, 17. Fourth pipeline, 18. Safety valve, 19. Safety valve front valve, 20. Safety valve rear valve, 21. Bypass pipeline, 22. Seventh valve, 23. Eighth valve, 24. Nitrogen pipeline, 25. Reformed oil distillation column feed line, 26. Ninth valve, 27. Drain pipeline, 28. Drain valve. Detailed Description of the Invention

[0031] The present invention will be described in detail below with reference to the accompanying drawings.

[0032] As shown in the figure, the improved drainage system of the KO liquid separator of the compressor includes: a KO liquid separator 1, with a first pipeline 2 and a second pipeline 3 respectively arranged on both sides of the KO liquid separator 1. The first pipeline 2 is connected to the pipeline led out from the compressor circulation process system. One end of the second pipeline 3 is connected to the KO liquid separator 1, and the other end is also connected to the pipeline led out from the compressor circulation process system; on one side of the KO liquid separator 1 in the same direction as the second pipeline, a KO liquid separator level gauge 4 is connected through a pipeline; a drainage pipeline 5 is arranged at the bottom of the KO liquid separator 1. The outlet of the drainage pipeline 5 is connected to the buffer tank system, the buffer tank system is connected to the nitrogen system, the top of the buffer tank system is connected to the flare system through a pipeline, and the bottom of the buffer tank is connected to the reformed oil rectification tower system;

[0033] A first valve 6 and a second valve 7 are respectively arranged on the first pipeline 2 and the second pipeline 3. The first pipeline 2 is connected to the lower part on one side of the KO liquid separator 1, and the second pipeline 3 is connected to the upper part on the other side of the KO liquid separator 1;

[0034] Further, a third valve 8 is arranged on the drainage pipeline 5;

[0035] Further, the buffer tank system includes: a buffer tank 9, a buffer tank level gauge 10, a pressure gauge 11 and valves; the buffer tank 9 is connected to the drainage pipeline 5 of the KO liquid separator through a third pipeline 12. A fourth valve 13 and a fifth valve 14 are arranged on the third pipeline 12. A pressure gauge 11 is arranged on the buffer tank 9. A buffer tank drainage pipeline 15 is arranged at the bottom of the buffer tank 9. A sixth valve 16 is arranged on the buffer tank drainage pipeline 15; on one side of the buffer tank 9 in the opposite direction to the third pipeline 12, a buffer tank level gauge 10 is arranged. The top directly above the buffer tank 9 is connected to the flare system through a fourth pipeline 17. A safety valve 18 is arranged on the fourth pipeline 17. A front valve 19 and a rear valve 20 are respectively arranged before and after the safety valve 18. The fourth pipeline 17 is also provided with a bypass pipeline 21. A seventh valve 22 and an eighth valve 23 are arranged on the bypass pipeline 21;

[0036] The nitrogen system includes: a nitrogen pipeline 24 and a three-valve group arranged on the nitrogen pipeline 24. The nitrogen pipeline 24 is connected to the upper end on one side of the buffer tank 9 in the same direction as the buffer tank level gauge 10. The three-valve group is arranged at the inlet position of the nitrogen pipeline 24, and nitrogen at 2.03 MPa is introduced into the nitrogen pipeline 24;

[0037] The described reformed oil distillation column system includes: a reformed oil distillation column feed line 25 connected to the reformed distillation column and a ninth valve 26 provided on the feed line, and a buffer tank drain line 15 is connected to the reformed oil distillation column feed line 24.

[0038] Further, the outlet position of the KO liquid separation tank drain line 5 is also branched with a drain line 27, and a drain valve 28 is provided on the drain line 27.

[0039] The draining method using the above draining system is as follows:

[0040] When the liquid level gauge 4 of the compressor KO liquid separation tank shows 10%-30%, after confirming the actual liquid level on site, draining operation is required;

[0041] First, close the drain valve 28, open the safety valve 18 and the front valve 19 and rear valve 20 of the safety valve, and close the seventh valve 22 and eighth valve 23 of the bypass line 21 of the fourth line 17;

[0042] Close the three-valve group of the nitrogen gas line 24, and then close the sixth valve 16 of the buffer tank drain line 15; the system pressure of the KO liquid separation tank 1 is 1.2 Mpa;

[0043] Then, open the third valve 8, fourth valve 13, and fifth valve 14, drain all the liquid in the KO liquid separation tank into the buffer tank 9, and then close the third valve 8 and fifth valve 14;

[0044] The pressure of the reformed oil distillation column feed line 25 is 0.4 MPa, and the pressure of the drained liquid to the buffer tank is 1 MPa. By monitoring the pressure gauge 11 of the buffer tank, after depressurizing to 0.5 MPa through the bypass line 21 of the fourth line 17, open the sixth valve 16 of the buffer tank drain line 15, drain the liquid onto the reformed oil distillation column feed line 25, and finally it is recycled by the reformed oil distillation column.

Claims

1. Improved method for draining liquid from the KO liquid separator of a compressor, characterized in that, Including: A KO knockout drum. On both sides of the KO knockout drum, there are a first pipeline and a second pipeline respectively. The first pipeline is connected to the pipeline led out from the compressor circulation process system. One end of the second pipeline is connected to the KO knockout drum, and the other end is also connected to the pipeline led out from the compressor circulation process system. On one side of the KO knockout drum in the same direction as the second pipeline, there is a KO knockout drum liquid level gauge connected by a pipeline. At the bottom of the KO knockout drum, there is a drain pipeline. The outlet of the drain pipeline is connected to the buffer tank system. The buffer tank system is connected to the nitrogen system. The top of the buffer tank system is connected to the flare system through a pipeline, and the bottom of the buffer tank is connected to the reformate distillation column system; A first valve and a second valve are respectively arranged on the first pipeline and the second pipeline. The first pipeline is connected to the lower part on one side of the KO knockout drum, and the second pipeline is connected to the upper part on the other side of the KO knockout drum; A third valve is arranged on the drain pipeline of the KO knockout drum. At the outlet position of the drain pipeline of the KO knockout drum, there is also a branched drain pipeline, and a drain valve is arranged on the drain pipeline; The buffer tank system includes: a buffer tank, a buffer tank liquid level gauge, a pressure gauge and valves. The buffer tank is connected to the drain pipeline of the KO knockout drum through a third pipeline. A fourth valve and a fifth valve are arranged on the third pipeline. A pressure gauge is arranged on the buffer tank. At the bottom of the buffer tank, there is a buffer tank drain pipeline, and a sixth valve is arranged on the buffer tank drain pipeline. On one side of the buffer tank in the opposite direction to the third pipeline, there is a buffer tank liquid level gauge. The top of the buffer tank is connected to the flare system through a fourth pipeline directly above. A safety valve is arranged on the fourth pipeline, and a front valve and a rear valve are respectively arranged before and after the safety valve. The fourth pipeline also has a branched bypass pipeline, and a seventh valve and an eighth valve are arranged on the bypass pipeline; The nitrogen system includes: a nitrogen pipeline and a three-valve group arranged on the nitrogen pipeline. The nitrogen pipeline is connected to the upper end on one side of the buffer tank in the same direction as the buffer tank liquid level gauge. The three-valve group is arranged at the inlet position of the nitrogen pipeline, and nitrogen with a pressure of 2.03 MPa is introduced from the nitrogen pipeline; The reformate distillation column system includes: a reformate distillation column feed line connected to the reformate distillation column and a ninth valve arranged on the feed line. The buffer tank drain pipeline is connected to the reformate distillation column feed line; When the liquid level gauge of the compressor KO knockout drum shows 10%-30%, after confirming the actual liquid level on site, a draining operation is required; First, close the drain valve, open the safety valve and the front valve and rear valve of the safety valve, and close the seventh valve and the eighth valve of the bypass pipeline of the fourth pipeline; Close the three-valve group of the nitrogen pipeline, and then close the sixth valve of the buffer tank drain pipeline; the pressure of the KO knockout drum system is 1.2 Mpa; Then, open the third valve, the fourth valve and the fifth valve. After draining all the liquid in the KO knockout drum into the buffer tank, close the third valve and the fifth valve; The pressure of the feed line of the reformate distillation column is 0.4 MPa, while the pressure of the liquid drained into the buffer tank is 1 MPa. By monitoring the pressure gauge of the buffer tank and relieving the pressure to 0.5 MPa through the bypass line of the fourth pipeline, the sixth valve of the buffer tank drain line is opened to drain the liquid onto the feed line of the reformate distillation column, and finally it is recycled by the reformate distillation column.

2. The improved method for draining liquid from the KO liquid separator of a compressor according to claim 1, characterized in that: The third pipeline, the buffer tank drain line, the fourth pipeline, and the bypass line of the fourth pipeline are all DN20, 300-pound pipelines.

3. The improved drainage method of the KO liquid separator of the compressor according to claim 1, wherein: The popping pressure of the safety valve is 1.8 MPa.

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