Wastewater zero discharge system

Abstract

The utility model discloses a wastewater zero discharge system, and particularly relates to the technical field of wastewater zero discharge of a thermal power plant, which comprises a pretreatment system, a concentration system is arranged on one side of the pretreatment system, a heat exchange system is arranged on the concentration system, and a condensation system and a tail end treatment system are arranged on one side of the concentration system; the pretreatment system comprises a high-salinity wastewater pool and a pretreatment device, and a pretreatment water feeding pump and a first electric valve are fixedly mounted between the high-salinity wastewater pool and the pretreatment device; according to the utility model, the pretreatment system is used for effectively pretreating high-salinity wastewater, the concentration system is used for concentrating the wastewater, and the condensation system is matched with the condensation system to condense moisture in humid and hot air; and the terminal treatment system is matched to electrolyze the concentrated wastewater to prepare acid and alkali liquor for subsequent recycling in a factory, so that the treatment effect of the high-salinity wastewater is effectively improved, and corrosion and scaling of equipment can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of zero-discharge of wastewater from thermal power plants, in particular to a zero-discharge system for wastewater. Background Art

[0002] With the improvement of national and local environmental protection requirements, higher requirements are being placed on the treatment and discharge of high-salinity wastewater. High-salinity wastewater such as circulating water, acid-base regeneration wastewater, and desulfurization wastewater from coal-fired power plants is usually required to be treated and reused and cannot be discharged. Therefore, "zero emission" treatment is required, which has become the focus and difficulty of coal-fired power plant wastewater treatment.

[0003] In recent years, “zero discharge” treatment technologies for high-salinity wastewater from coal-fired power plants have emerged one after another, and various process technologies have developed rapidly, such as multi-effect forced circulation evaporation crystallization (MED), mechanical vapor recompression evaporation crystallization (MVR), bypass flue evaporation, and flue atomization evaporation.

[0004] Among them, MED and MVR evaporation crystallization technology equipment have the problems of corrosion and scaling, flue evaporation drying treatment technology and bypass flue evaporation drying technology. The amount of water absorbed is affected by many factors such as the unit operation status and unit load. Therefore, it is urgent to develop a new wastewater zero discharge process to solve the technical barriers of the existing wastewater zero discharge process. Utility Model Content

[0005] The purpose of the present invention is to provide a wastewater zero discharge system to solve the problems raised in the above background technology.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A wastewater zero discharge system comprises a pretreatment system, a concentration system is provided on one side of the pretreatment system, a heat exchange system is provided on the concentration system, and a condensation system and a terminal treatment system are provided on one side of the concentration system;

[0008] The pretreatment system includes a high-salt wastewater pool and a pretreatment device, wherein a pretreatment water pump and a first electric valve are fixedly installed between the high-salt wastewater pool and the pretreatment device;

[0009] The concentration system includes a concentration tower body and a blower. A concentration tower water supply pump and a second electric valve are fixedly installed between the concentration tower body and the pretreatment device. An air dryer is fixedly installed between the concentration tower body and the blower. A concentration tower spray device is provided on the top of the concentration tower body. A concentrate circulation pump is provided at the bottom of the concentration tower body. The output port of the concentrate circulation pump is fixedly connected to the concentration tower spray device. A concentrate delivery pump is provided at the bottom of the concentration tower body. A concentrate wastewater tank is provided at the end of the concentrate delivery pump. A third electric valve is provided between the concentrate delivery pump and the concentrate wastewater tank.

[0010] In one possible implementation, the heat exchange system includes a desulfurization tower and a heat exchange device, a desulfurization slurry circulation pump is fixedly installed at the bottom of the desulfurization tower, the outlet of the desulfurization slurry circulation pump is connected to the upper part of the desulfurization tower, the heat exchange device is fixedly installed on the outlet pipe of the desulfurization slurry circulation pump, and a fourth electric valve is provided on the pipe between the heat exchange device and the desulfurization slurry circulation pump.

[0011] In a possible implementation, the heat exchange device is fixedly installed on the concentrate circulation pump pipeline.

[0012] In one possible implementation, the condensation system includes a cooling tower body and a cooling water tower, a cooling tower spray device is provided on the top of the cooling tower body, a cooling water return pump and a sixth electric valve are provided between the bottom of the cooling tower body and the cooling water tower, and a cooling water pump and a fifth electric valve are provided between the cooling water tower and the cooling tower spray device.

[0013] In a possible implementation, the concentrating tower body and the cooling tower body are connected.

[0014] In a possible implementation, the terminal treatment system includes bipolar membrane electrodialysis, and an electrodialysis water supply pump and a seventh electric valve are provided between the bipolar membrane electrodialysis and the concentrate wastewater tank.

[0015] In a possible implementation, the terminal treatment system further includes an alkali storage tank and an acid storage tank, wherein the input port of the alkali storage tank is connected to the output port of the bipolar membrane electrodialysis, and the input port of the acid storage tank is connected to the output port of the bipolar membrane electrodialysis.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. Effectively pre-treat high-salt wastewater by setting up a pretreatment system, and use a concentration system to concentrate the wastewater. In conjunction with the use of a condensation system, condense moisture in the hot and humid air, and use a terminal treatment system to electrolyze the concentrated wastewater to prepare acid and alkali solutions, which are then reused in the plant. This effectively improves the treatment effect of high-salt wastewater and can reduce equipment corrosion and scaling.

[0018] 2. By setting up a heat exchange system, the temperature of the desulfurized slurry can be transferred to the wastewater of the concentration system to increase the temperature of the wastewater, facilitate subsequent wastewater treatment, and thus realize heat recovery and utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a structural diagram of a wastewater zero discharge system of the utility model.

[0021] Figure 2 This is a system flow chart of a zero wastewater discharge system of the utility model.

[0022] In the figure: 1. Pretreatment system; 11. High-salt wastewater tank; 12. Pretreatment water pump; 13. First electric valve; 14. Pretreatment device; 2. Concentration system; 21. Concentration tower water pump; 22. Second electric valve; 23. Concentration tower body; 231. Concentration tower spray device; 24. Blower; 25. Air dryer; 26. Concentrate circulation pump; 27. Concentrate delivery pump; 28. Third electric valve; 29. ​​Concentrate wastewater tank; 3. Heat exchange system; 3 1. Desulfurization tower; 32. Desulfurization slurry circulation pump; 33. Fourth electric valve; 34. Heat exchange device; 4. Condensation system; 41. Cooling tower body; 411. Cooling tower spray device; 42. Cooling water return pump; 43. Sixth electric valve; 44. Cooling tower; 45. Cooling water pump; 46. Fifth electric valve; 5. Terminal treatment system; 51. Electrodialysis feed water pump; 52. Seventh electric valve; 53. Bipolar membrane electrodialysis; 54. Alkali storage tank; 55. Acid storage tank. DETAILED DESCRIPTION

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

[0024] Example: Figure 1-2 As shown, the utility model provides a wastewater zero discharge system, including a pretreatment system 1, a concentration system 2 is provided on one side of the pretreatment system 1, so that the wastewater treated by the pretreatment system 1 enters the concentration system 2 for concentration, a heat exchange system 3 is provided on the concentration system 2, and a condensation system 4 and a terminal treatment system 5 are provided on one side of the concentration system 2, so that the moisture carried away by the dry air in the concentration system 2 enters the condensation system 4, and the wastewater concentrated by the concentration system 2 is introduced into the terminal treatment system 5 for zero discharge wastewater treatment;

[0025] The pretreatment system 1 includes a high-salt wastewater tank 11 and a pretreatment device 14. The pretreatment device 14 is one or more of a high-density sedimentation tank, a mechanical stirring clarifier, a high-efficiency cyclone purifier, a fiber filter, a multi-media filter, etc. The turbidity of the effluent from the pretreatment system 1 is ≤20NTU. A pretreatment water supply pump 12 and a first electric valve 13 are fixedly installed between the high-salt wastewater tank 11 and the pretreatment device 14. The high-salt wastewater tank 11 provides high-salt wastewater to the pretreatment device 14 for pretreatment.

[0026] The concentration system 2 includes a concentration tower body 23 and a blower 24. A concentration tower water pump 21 and a second electric valve 22 are fixedly installed between the inlet pipeline of the concentration tower body 23 and the pretreatment device 14. The concentration tower body 23 concentrates the pretreated high-salt wastewater;

[0027] An air dryer 25 is fixedly installed on the pipe between the concentration tower body 23 and the blower 24. The air is dried by the air dryer 25 and then introduced into the concentration tower body 23 when the blower 24 is turned on.

[0028] A concentration tower spray device 231 is provided at the top of the concentration tower body 23, and a concentrate circulation pump 26 is provided at the bottom of the concentration tower body 23. The output port of the concentrate circulation pump 26 is fixedly connected to the concentration tower spray device 231. The high-salt wastewater in the concentration tower body 23 is circulated and sprayed through the concentration tower spray device 231 to increase the contact area between the dry air and the wastewater.

[0029] In one possible embodiment, the heat exchange system 3 includes a desulfurization tower 31 and a heat exchange device 34. A desulfurization slurry circulation pump 32 is fixedly installed at the bottom of the desulfurization tower 31. The outlet of the desulfurization slurry circulation pump 32 is connected to the upper part of the desulfurization tower 31. The heat exchange device 34 is fixedly installed on the outlet pipe of the desulfurization slurry circulation pump 32. The desulfurization tower 31 is used to remove sulfur oxides from the flue gas, and the desulfurization slurry circulation pump 32 is used to circulate the desulfurization slurry.

[0030] A fourth electric valve 33 is provided on the pipeline between the heat exchange device 34 and the desulfurization slurry circulation pump 32. The heat exchange device 34 is fixedly installed on the pipeline of the concentrated liquid circulation pump 26. The heat exchange device 34 is used to realize heat exchange between the desulfurization slurry and the wastewater of the desulfurization tower 31, and is used to increase the water temperature of the wastewater output by the concentrated liquid circulation pump 26, and increase the concentration rate of the wastewater in the concentration tower body 23.

[0031] In one possible embodiment, the condensation system 4 includes a cooling tower body 41 and a cooling water tower 44. The concentrating tower body 23 and the cooling tower body 41 are connected. The cooling tower body 41 is used to cool the moisture carried by the dry air in the concentrating tower body 23 to achieve fresh water reuse; the cooling water tower 44 has circulating cooling water.

[0032] The cooling tower body 41 is open in design. A cooling tower spray device 411 is provided on the top of the cooling tower body 41. A cooling water return pump 42 and a sixth electric valve 43 are provided between the bottom of the cooling tower body 41 and the cooling water tower 44. A cooling water pump 45 and a fifth electric valve 46 are provided between the cooling water tower 44 and the cooling tower spray device 411.

[0033] A concentrate delivery pump 27 is provided at the bottom of the concentration tower body 23. A concentrate wastewater tank 29 is provided at the end of the concentrate delivery pump 27. A third electric valve 28 is provided between the concentrate delivery pump 27 and the concentrate wastewater tank 29. When the concentrate delivery pump 27 and the third electric valve 28 are opened, the concentrate in the concentration tower body 23 is transferred to the concentrate wastewater tank 29 for storage.

[0034] In one possible embodiment, the terminal treatment system 5 includes a bipolar membrane electrodialysis 53, which is used to electrolyze high-salt wastewater to prepare acid and alkali solutions. An electrodialysis water supply pump 51 and a seventh electric valve 52 are provided between the bipolar membrane electrodialysis 53 and the concentrated liquid wastewater tank 29.

[0035] In one possible embodiment, the terminal treatment system 5 also includes an alkali storage tank 54 and an acid storage tank 55. The input port of the alkali storage tank 54 is connected to the output port of the bipolar membrane electrodialysis 53. The alkali storage tank 54 is used to store the alkali solution generated by electrolysis of the bipolar membrane electrodialysis 53. The input port of the acid storage tank 55 is connected to the output port of the bipolar membrane electrodialysis 53. The acid storage tank 55 is used to store the acid solution generated by electrolysis of the bipolar membrane electrodialysis 53.

[0036] Working principle: When in use, open the pretreatment water pump 12 and the first electric valve 13 to transport the wastewater in the high-salt wastewater pool 11 to the pretreatment device 14 for pretreatment, reduce the suspended solids in the wastewater, and make the turbidity of the produced water less than 20NTU, effectively reducing corrosion and scaling during subsequent equipment treatment;

[0037] Open the second electric valve 22 and the concentration tower water pump 21 to transport the pretreated wastewater to the concentration tower body 23 for concentration. Simultaneously open the blower 24 and the air dryer 25 to transport dry air to the concentration tower body 23 for concentration. Open the concentrate circulation pump 26 to circulate the wastewater in the concentration tower body 23 to the concentration tower spray device 231 for spraying. At the same time, open the fourth electric valve 33 and the desulfurization slurry circulation pump 32 to circulate the desulfurization slurry in the heat exchange device 34, so that the heat of the desulfurization slurry is transferred to the wastewater at the outlet of the concentrate circulation pump 26, thereby increasing the temperature of the wastewater.

[0038] The hot and humid air carried by the dry air in the concentration tower body 23 is transported to the cooling tower body 41. The fifth electric valve 46 and the cooling water pump 45 are opened to transport the circulating water in the cooling tower 44 to the cooling tower spray device 411 for spraying, thereby condensing the moisture in the hot and humid air.

[0039] Open the sixth electric valve 43 and the cooling water return pump 42 to return the cooling water in the cooling tower body 41 to the cooling water tower 44; at the same time, open the third electric valve 28 and the concentrate delivery pump 27 to deliver the concentrated wastewater in the concentration tower body 23 to the concentrated liquid wastewater tank 29; open the seventh electric valve 52 and the electrodialysis water supply pump 51 to deliver the wastewater in the concentrated liquid wastewater tank 29 to the bipolar membrane electrodialysis 53 for electrolysis to prepare acid and alkali solution. The alkali solution is stored in the alkali storage tank 54, and the acid solution is stored in the acid storage tank 55 for subsequent reuse in the factory.

[0040] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A zero-discharge wastewater system, comprising a pretreatment system (1), characterized in that: A concentration system (2) is provided on one side of the pretreatment system (1), a heat exchange system (3) is provided on the concentration system (2), and a condensation system (4) and a terminal treatment system (5) are provided on one side of the concentration system (2); The pretreatment system (1) comprises a high-salt wastewater pool (11) and a pretreatment device (14), wherein a pretreatment water pump (12) and a first electric valve (13) are fixedly installed between the high-salt wastewater pool (11) and the pretreatment device (14); The concentration system (2) comprises a concentration tower body (23) and a blower (24); a concentration tower water supply pump (21) and a second electric valve (22) are fixedly installed between the concentration tower body (23) and the pretreatment device (14); an air dryer (25) is fixedly installed between the concentration tower body (23) and the blower (24); a concentration tower spray device (231) is provided at the top of the concentration tower body (23); a concentrated liquid circulation pump (26) is provided at the bottom of the concentration tower body (23); the output port of the concentrated liquid circulation pump (26) is fixedly connected to the concentration tower spray device (231); a concentrated liquid delivery pump (27) is provided at the bottom of the concentration tower body (23); a concentrated liquid wastewater tank (29) is provided at the end of the concentrated liquid delivery pump (27); and a third electric valve (28) is provided between the concentrated liquid delivery pump (27) and the concentrated liquid wastewater tank (29).

2. A zero wastewater discharge system according to claim 1, characterized in that: The heat exchange system (3) includes a desulfurization tower (31) and a heat exchange device (34). A desulfurization slurry circulation pump (32) is fixedly installed at the bottom of the desulfurization tower (31). The outlet of the desulfurization slurry circulation pump (32) is connected to the upper part of the desulfurization tower (31). The heat exchange device (34) is fixedly installed on the outlet pipe of the desulfurization slurry circulation pump (32). A fourth electric valve (33) is provided on the pipe between the heat exchange device (34) and the desulfurization slurry circulation pump (32).

3. A zero wastewater discharge system according to claim 2, characterized in that: The heat exchange device (34) is fixedly installed on the pipeline of the concentrated liquid circulation pump (26).

4. A zero wastewater discharge system according to claim 1, characterized in that: The condensing system (4) comprises a cooling tower body (41) and a cooling water tower (44); a cooling tower spray device (411) is provided on the top of the cooling tower body (41); a cooling water return pump (42) and a sixth electric valve (43) are provided between the bottom of the cooling tower body (41) and the cooling water tower (44); and a cooling water pump (45) and a fifth electric valve (46) are provided between the cooling water tower (44) and the cooling tower spray device (411).

5. A zero wastewater discharge system according to claim 4, characterized in that: The concentration tower body (23) and the cooling tower body (41) are in communication.

6. A zero wastewater discharge system according to claim 1, characterized in that: The terminal treatment system (5) includes a bipolar membrane electrodialysis (53), and an electrodialysis water supply pump (51) and a seventh electric valve (52) are provided between the bipolar membrane electrodialysis (53) and the concentrated liquid wastewater tank (29).

7. A zero wastewater discharge system according to claim 6, characterized in that: The terminal treatment system (5) further comprises an alkali storage tank (54) and an acid storage tank (55), wherein the input port of the alkali storage tank (54) is connected to the output port of the bipolar membrane electrodialysis (53), and the input port of the acid storage tank (55) is connected to the output port of the bipolar membrane electrodialysis (53).

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