Benzene-containing sewage recovery system

Abstract

The utility model provides a benzene-containing sewage recovery system. The benzene tower is connected with a benzene and toluene aromatic hydrocarbon feeding self-extraction unit through a pipeline, a top outlet of the benzene tower is connected with an air cooler through a benzene tower gas phase line, and the air cooler is connected with a benzene tower return tank; the benzene tower reflux tank outlet is connected with the benzene tower through a pipeline; the benzene tower return tank is provided with a benzene-containing sewage water bag, the benzene-containing sewage water bag is connected to the dirty oil tank and the oil-containing sewage tank through a water bag drainage pipeline, the water bag drainage pipeline is connected with a recovery pipeline, the recovery pipeline is sequentially connected with a filter, a sewage pump and a recovery regulating valve, and the recovery pipeline is connected with an aromatic hydrocarbon recovery tower return tank water bag; the return tank water drum of the aromatic hydrocarbon recovery tower is arranged on the return tank of the aromatic hydrocarbon recovery tower; the arene recovery tower return tank is connected with the extraction unit arene recovery tower through a recovery tower top gas phase pipe; benzene-containing sewage can be recycled continuously, and the sewage is not discharged any more; the sewage treatment cost is reduced; meanwhile, the contact risk of operators to cancerogens is reduced.

Description

Technical Field

[0001] This utility model belongs to the technical field of benzene-containing wastewater recovery and utilization in benzene towers and benzene-toluene extraction units of aromatic hydrocarbon plants, and in particular, a benzene-containing wastewater recovery system. Background Technology

[0002] The benzene distillation column (benzene rectification column) in the aromatics unit separates petroleum benzene products through distillation. The vapor phase at the top of the column is cooled by an air cooler and sent to the benzene distillation column reflux tank for reflux. The C7+ aromatics (toluene and higher-order components) at the bottom of the column are sent to the toluene column for further toluene separation. Since the feedstock for the benzene column is a mixture of benzene and toluene aromatics produced by the benzene and toluene extraction unit, and the sulfolane solvent in the extraction unit contains water, this process is designed to prevent water contamination in the petroleum benzene products. The water also contains trace amounts of benzene. Furthermore, the extraction unit itself requires water replenishment during operation. Therefore, the benzene and toluene aromatics contain a small amount of water, which needs to be removed in the water tank of the benzene distillation column reflux tank. The oily wastewater undergoes simple treatment before being sent to a wastewater treatment plant for further treatment before being discharged.

[0003] However, benzene is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization. Therefore, reducing the discharge of this portion of water and small amounts of benzene not only reduces wastewater treatment costs but also reduces the risk of exposure to carcinogens for operators. Utility Model Content

[0004] In view of the above problems, the purpose of this application is to provide a benzene-containing wastewater recycling system that enables the continued recycling and reuse of benzene-containing wastewater, and prevents further discharge of wastewater.

[0005] To achieve some or all of the above objectives or other objectives, this application provides the following technical solution: a benzene-containing wastewater recovery system, comprising a benzene tower, an air cooler, a benzene tower reflux tank, a benzene-containing wastewater water tank, a recovery pipeline, an aromatic hydrocarbon recovery tower reflux tank, and an aromatic hydrocarbon recovery tower reflux tank water tank; the first inlet of the benzene tower is connected to a benzene and toluene aromatic hydrocarbon feed self-extraction unit via a pipeline; the top outlet of the benzene tower is connected to the air cooler inlet via a benzene tower vapor phase line; the first outlet of the air cooler is connected to the first inlet of the benzene tower reflux tank via an air cooler outlet condensate to reflux tank pipeline; and the second outlet of the air cooler is connected to the benzene tower reflux tank via an air cooler non-condensable gas line. The benzene tower reflux tank outlet is connected to the benzene tower inlet 2 via a pipeline; a benzene-containing wastewater tank is installed on the benzene tower reflux tank, and the inlet of the benzene-containing wastewater tank is connected to the sludge tank and the oily wastewater tank via a water tank drainage pipeline. The water tank drainage pipeline is connected to the recovery pipeline inlet, and the recovery pipeline is sequentially connected to a filter, a wastewater pump, and a recovery regulating valve. The recovery pipeline outlet is connected to the aromatic hydrocarbon recovery tower reflux tank water tank inlet; the aromatic hydrocarbon recovery tower reflux tank water tank is installed on the aromatic hydrocarbon recovery tower reflux tank; the aromatic hydrocarbon recovery tower reflux tank inlet is connected to the extraction unit aromatic hydrocarbon recovery tower outlet via the recovery tower top gas phase pipe.

[0006] Furthermore, the benzene tower reflux tank and the benzene-containing wastewater tank are integrated into one unit, and the aromatic hydrocarbon recovery tower reflux tank and the aromatic hydrocarbon recovery tower reflux tank water tank are integrated into one unit.

[0007] Furthermore, a water jacket drainage regulating valve is connected to the water jacket drainage pipeline, and the water jacket drainage regulating valve is connected to the inlet of the recovery pipeline.

[0008] Furthermore, an automatic start / stop control device for the sewage pump is connected between the benzene-containing wastewater bag and the sewage pump.

[0009] Furthermore, nitrogen gas is introduced into the benzene tower reflux tank through the reflux tank nitrogen replenishment pipeline, the reflux tank nitrogen replenishment pipeline is connected to the inlet of the reflux tank flare pipeline, and the reflux tank flare pipeline outlet is connected to the flare.

[0010] Furthermore, the outlet of the benzene tower reflux tank is connected to the inlet of the benzene tower reflux pump via a reflux pump pipeline, the outlet of the benzene tower reflux pump is connected to the second inlet of the benzene tower via a benzene tower reflux line, and the benzene tower reflux regulating valve group is connected to the benzene tower reflux line.

[0011] Furthermore, the first outlet of the benzene tower is connected to the inlet of the benzene product pump pipeline, and the benzene product pump pipeline is sequentially connected to the benzene product pump, the benzene product water cooler, and the benzene extraction regulating valve group; the outlet of the benzene product pump pipeline is connected to the benzene product storage tank through the qualified benzene extraction pipeline, and the outlet of the benzene product pump pipeline is also connected to the unqualified benzene disproportionation clay feed tank through the unqualified benzene extraction pipeline.

[0012] Furthermore, a benzene tower reboiler pipeline is connected to the benzene tower, and a reboiler is connected to the benzene tower reboiler pipeline.

[0013] Furthermore, the bottom outlet of the benzene tower is connected to the toluene tower via a benzene tower bottom outlet pipeline, which is sequentially connected to the benzene tower bottom pump and the benzene tower bottom outlet regulating valve group.

[0014] Compared with the prior art, the beneficial effects of this utility model are: by adding the recycling pipeline and regulating valve to the sewage reuse line of the extraction unit, the benzene-containing sewage can be further recycled and reused, and the sewage will no longer be discharged; this not only reduces the sewage treatment cost but also reduces the risk of operators being exposed to carcinogens. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] In the diagram: 1. Recovery pipeline; 2. Wastewater pump; 3. Recovery regulating valve; 4. Aromatic hydrocarbon recovery tower reflux tank; 401. Aromatic hydrocarbon recovery tower reflux tank water tank; 5. Recovery tower top vapor phase pipe; 6. Extraction unit aromatic hydrocarbon recovery tower; 7. Qualified benzene extraction pipeline; 8. Unqualified benzene extraction pipeline; 9. Benzene extraction regulating valve assembly; 10. Benzene product water cooler; 11. Benzene product pump; 12. Benzene product pump pipeline; 13. Benzene, toluene, and aromatic hydrocarbon feed pipeline self-extraction unit; 14. Benzene tower; 15. Benzene tower reboiler pipeline; 16. Benzene tower bottom pump; 17. Benzene tower bottom extraction pipeline; 18. Benzene tower bottom extraction regulating valve. 19. Benzene Tower Vapor Phase Line; 20. Air Cooler; 21. Air Cooler Non-condensable Gas Line; 22. Air Cooler Outlet Condensate to Reflux Tank Line; 23. Benzene Tower Reflux Tank; 2301. Benzene-Containing Wastewater Water Bundle; 24. Reflux Tank Nitrogen Makeup Line; 25. Reflux Tank Flare Line; 26. Reflux Pump Line; 27. Benzene Tower Reflux Pump; 28. Benzene Tower Reflux Regulating Valve Assembly; 29. ​​Benzene Tower Reflux Line; 30. Water Bundle Drain Regulating Valve; 31. Water Bundle Drain Line; 32. Filter; 33. Benzene Product to Storage Tank; 34. Non-conforming Benzene Disproportionation Clay Feed Tank; 35. Reboiler; 36. Toluene Tower. Detailed Implementation

[0017] To make the structure and function of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0018] See appendix Figure 1A benzene-containing wastewater recovery system includes a benzene tower 14, an air cooler 20, a benzene tower reflux tank 23, a benzene-containing wastewater water tank 2301, a recovery pipeline 1, an aromatic hydrocarbon recovery tower reflux tank 4, and an aromatic hydrocarbon recovery tower reflux tank water tank 401. The first inlet of the benzene tower 14 is connected to a benzene and toluene aromatic hydrocarbon feed self-extraction unit 13 via a pipeline. The top outlet of the benzene tower 14 is connected to the inlet of the air cooler 20 via a benzene tower vapor line 19. The first outlet of the air cooler 20 is connected to the first inlet of the benzene tower reflux tank 23 via an air cooler outlet condensate to reflux tank pipeline 22. The second outlet of the air cooler 20 is connected to the second inlet of the benzene tower reflux tank 23 via an air cooler non-condensable gas line 21. The outlet of the benzene tower reflux tank 23 is connected to the benzene tower 14 via a pipeline. 4. Inlet No. 2; The benzene tower reflux tank 23 is equipped with a benzene-containing wastewater tank 2301. The inlet of the benzene-containing wastewater tank 2301 is connected to the sludge tank and the oily wastewater tank through the tank drain line 31. The inlet of the recovery line 1 is connected to the drain line 31. The recovery line 1 is connected in sequence to the filter 32, the wastewater pump 2 and the recovery regulating valve 3. The outlet of the recovery line 1 is connected to the inlet of the aromatic hydrocarbon recovery tower reflux tank water tank 401. The aromatic hydrocarbon recovery tower reflux tank water tank 401 is installed on the aromatic hydrocarbon recovery tower reflux tank 4. The inlet of the aromatic hydrocarbon recovery tower reflux tank 4 is connected to the outlet of the extraction unit aromatic hydrocarbon recovery tower 6 through the gas phase pipe 5 at the top of the recovery tower. The main function of the extraction unit aromatic hydrocarbon recovery tower 6 is to separate benzene and toluene.

[0019] The benzene tower reflux tank 23 and the benzene-containing wastewater water tank 2301 are integrated, and the aromatic hydrocarbon recovery tower reflux tank 4 and the aromatic hydrocarbon recovery tower reflux tank water tank 401 are integrated; they are integrated welded equipment; the function of the water tank is to separate benzene, toluene aromatics and water.

[0020] The water jacket drainage pipeline 31 is connected to the water jacket drainage regulating valve 30, which is connected to the inlet of the recovery pipeline 1.

[0021] An automatic start / stop control device for the sewage pump is connected between the benzene-containing wastewater package 2301 and the sewage pump 2.

[0022] Nitrogen gas is introduced into the benzene tower reflux tank 23 through the reflux tank nitrogen supply line 24. The reflux tank nitrogen supply line 24 is connected to the inlet of the reflux tank flare line 25, and the outlet of the reflux tank flare line 25 is connected to the flare.

[0023] The outlet of the benzene tower reflux tank 23 is connected to the inlet of the benzene tower reflux pump 27 via the reflux pump pipeline 26. The outlet of the benzene tower reflux pump 27 is connected to the second inlet of the benzene tower 14 via the benzene tower reflux line 29. The benzene tower reflux regulating valve group 28 is connected to the benzene tower reflux line 29.

[0024] The first outlet of the benzene tower 14 is connected to the inlet of the benzene product pump pipeline 12. The benzene product pump pipeline 12 is sequentially connected to the benzene product pump 11, the benzene product water cooler 10, and the benzene extraction regulating valve group 9. The outlet of the benzene product pump pipeline 12 is connected to the benzene product storage tank 33 through the qualified benzene extraction pipeline 7. The outlet of the benzene product pump pipeline 12 is also connected to the unqualified benzene disproportionation clay feed tank 34 through the unqualified benzene extraction pipeline 8.

[0025] The benzene tower 14 is connected to the benzene tower reboiler line 15, and the benzene tower reboiler line 15 is connected to the reboiler 35.

[0026] The bottom outlet of the benzene tower 14 is connected to the toluene tower 36 via the benzene tower bottom outlet pipeline 17. The benzene tower bottom outlet pipeline 17 is connected in sequence to the benzene tower bottom pump 16 and the benzene tower bottom outlet regulating valve group 18.

[0027] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A benzene-containing wastewater recovery system, characterized in that: The system includes a benzene tower (14), an air cooler (20), a benzene tower reflux tank (23), a benzene-containing wastewater tank (2301), a recovery pipeline (1), an aromatic hydrocarbon recovery tower reflux tank (4), and an aromatic hydrocarbon recovery tower reflux tank water tank (401). The first inlet of the benzene tower (14) is connected to the benzene and toluene aromatic hydrocarbon feed self-extraction unit (13) via a pipeline. The top outlet of the benzene tower (14) is connected to the inlet of the air cooler (20) via the benzene tower vapor line (19). The first outlet of the air cooler (20) is connected to the first inlet of the benzene tower reflux tank (23) via the air cooler outlet condensate to reflux tank pipeline (22). The second outlet of the air cooler (20) is connected to the second inlet of the benzene tower reflux tank (23) via the air cooler non-condensable gas line (21). The outlet of the benzene tower reflux tank (23) is connected to the second inlet of the benzene tower reflux tank (23) via the air cooler non-condensable gas line (21). The pipeline is connected to the second inlet of the benzene tower (14); a benzene-containing wastewater water bag (2301) is installed on the benzene tower reflux tank (23), and the inlet of the benzene-containing wastewater water bag (2301) is connected to the sludge tank and the oily wastewater tank through the water bag drainage pipeline (31). The inlet of the recovery pipeline (1) is connected to the water bag of the reflux tank of the aromatic hydrocarbon recovery tower. The filter (32), the wastewater pump (2) and the recovery regulating valve (3) are connected in sequence on the recovery pipeline (1). The outlet of the recovery pipeline (1) is connected to the inlet of the water bag (401) of the reflux tank of the aromatic hydrocarbon recovery tower; the water bag (401) of the reflux tank of the aromatic hydrocarbon recovery tower is installed on the reflux tank (4) of the aromatic hydrocarbon recovery tower; the inlet of the reflux tank (4) of the aromatic hydrocarbon recovery tower is connected to the outlet of the aromatic hydrocarbon recovery tower (6) of the extraction unit through the gas phase pipe (5) at the top of the recovery tower.

2. The benzene-containing wastewater recovery system according to claim 1, characterized in that: The benzene tower reflux tank (23) and the benzene-containing wastewater tank (2301) are integrated, and the aromatic hydrocarbon recovery tower reflux tank (4) and the aromatic hydrocarbon recovery tower reflux tank water tank (401) are integrated.

3. The benzene-containing wastewater recovery system according to claim 1, characterized in that: The water-bag drainage pipeline (31) is connected to a water-bag drainage regulating valve (30), which is connected to the inlet of the recovery pipeline (1).

4. The benzene-containing wastewater recovery system according to claim 1, characterized in that: An automatic start / stop control device for the sewage pump is connected between the benzene-containing sewage bag (2301) and the sewage pump (2).

5. The benzene-containing wastewater recovery system according to claim 1, characterized in that: Nitrogen gas is introduced into the benzene tower reflux tank (23) through the reflux tank nitrogen replenishment pipeline (24). The reflux tank nitrogen replenishment pipeline (24) is connected to the inlet of the reflux tank flare pipeline (25), and the outlet of the reflux tank flare pipeline (25) is connected to the flare.

6. The benzene-containing wastewater recovery system according to claim 1, characterized in that: The outlet of the benzene tower reflux tank (23) is connected to the inlet of the benzene tower reflux pump (27) via the reflux pump pipeline (26). The outlet of the benzene tower reflux pump (27) is connected to the second inlet of the benzene tower (14) via the benzene tower reflux line (29). The benzene tower reflux regulating valve group (28) is connected to the benzene tower reflux line (29).

7. The benzene-containing wastewater recovery system according to claim 1, characterized in that: The outlet of the benzene tower (14) is connected to the inlet of the benzene product pump pipeline (12). The benzene product pump pipeline (12) is connected in sequence to the benzene product pump (11), the benzene product water cooler (10) and the benzene extraction regulating valve group (9). The outlet of the benzene product pump pipeline (12) is connected to the benzene product storage tank (33) through the qualified benzene extraction pipeline (7). The outlet of the benzene product pump pipeline (12) is also connected to the unqualified benzene disproportionation clay feed tank (34) through the unqualified benzene extraction pipeline (8).

8. The benzene-containing wastewater recovery system according to claim 1, characterized in that: The benzene tower (14) is connected to the benzene tower reboiler line (15), and the benzene tower reboiler line (15) is connected to the reboiler (35).

9. A benzene-containing wastewater recovery system according to claim 1, characterized in that: The bottom outlet of the benzene tower (14) is connected to the toluene tower (36) through the benzene tower bottom outlet pipeline (17), and the benzene tower bottom outlet pipeline (17) is connected in sequence to the benzene tower bottom pump (16) and the benzene tower bottom outlet regulating valve group (18).

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