Multistage membrane concentration treatment device for coal mine high-salinity wastewater

Abstract

The utility model discloses a multistage membrane concentration treatment device for coal mine high-salinity wastewater, and relates to the technical field of sewage treatment. Comprising a product water tank, a filter pressing system, a first-stage ultrafiltration pretreatment system, a first-stage reverse osmosis concentration system, a second-stage tubular microfiltration pretreatment system, a second-stage reverse osmosis concentration system, a third-stage tubular microfiltration pretreatment system, a third-stage ion exchange pretreatment system, a third-stage concentration reverse osmosis system and a concentrated brine tank, reverse osmosis water outlets of the first-stage reverse osmosis concentration system, the second-stage reverse osmosis concentration system and the third-stage concentration reverse osmosis system are all communicated with the product water tank, and drain outlets of the second-stage tubular microfiltration pretreatment system, the third-stage tubular microfiltration pretreatment system and the third-stage ion exchange pretreatment system are all communicated with the filter pressing system. According to the utility model, the utilization of water resources is improved, the effective treatment of high-concentration wastewater is finally realized, and the mine water resources are recycled to the maximum extent.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a multi-stage membrane concentration treatment device for high-salt coal mine wastewater. Background Technology

[0002] With the development of the modern coal chemical industry, coal, as one of the main fossil energy sources, plays a vital role in the energy and chemical fields. However, the processing and utilization of coal inevitably generates a large amount of high-salinity wastewater. The total dissolved solids (TDS) content in this wastewater often exceeds 3.5%, and it contains various salts and organic matter, posing a serious threat to the environment and ecology. Therefore, developing efficient and environmentally friendly high-salinity wastewater treatment technologies to achieve the resource utilization of wastewater has become crucial for the sustainable development of the coal chemical industry.

[0003] Therefore, how to provide a multi-stage membrane concentration treatment device for high-salt coal mine wastewater has become a problem that needs to be considered by those skilled in the art. Utility Model Content

[0004] In view of this, the present invention provides a multi-stage membrane concentration treatment device for high-salt coal mine wastewater. The present invention uses a multi-stage reverse osmosis unit to highly concentrate the wastewater while ensuring the quality of the produced water, thereby improving the wastewater recovery rate and reducing environmental pollution.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A multi-stage membrane concentration treatment device for high-salt coal mine wastewater includes a product water tank, a filter press system, and a series of sequentially connected components: a primary ultrafiltration pretreatment system, a primary reverse osmosis concentration system, a secondary tubular microfiltration pretreatment system, a secondary reverse osmosis concentration system, a tertiary tubular microfiltration pretreatment system, a tertiary ion exchange pretreatment system, a tertiary concentration reverse osmosis system, and a concentrated brine tank. The reverse osmosis concentrate outlets of the primary, secondary, and tertiary concentration reverse osmosis systems are all connected to the product water tank, and the wastewater outlets of the secondary, tertiary tubular microfiltration pretreatment systems, and the tertiary ion exchange pretreatment systems are all connected to the filter press system.

[0007] Furthermore, the primary ultrafiltration pretreatment system includes a first booster pump, a self-cleaning filter, an ultrafiltration membrane module, and an ultrafiltration product water tank. The inlet of the first booster pump is connected to the mine water treatment system, the outlet of the first booster pump is connected to the inlet of the self-cleaning filter, the outlet of the self-cleaning filter is connected to the ultrafiltration membrane module, the ultrafiltration membrane module is connected to the inlet of the ultrafiltration product water tank, and the concentrated water is returned to the mine water treatment system.

[0008] Furthermore, the primary reverse osmosis concentration system includes a second booster pump, a precision filter, a first security filter, a first booster pump, a primary reverse osmosis membrane module, an antiscalant dosing device, a first chemical cleaning system, and a primary concentrate tank. The inlet of the second booster pump is connected to the outlet of the product water tank of the primary ultrafiltration pretreatment system. The outlet of the second booster pump is connected to the inlet of the precision filter. The outlet of the precision filter is connected to the inlet of the first security filter. The outlet of the security filter is connected to the inlet of the first booster pump. The outlet of the first booster pump is connected to the inlet of the primary reverse osmosis membrane module. The concentrate from the primary reverse osmosis membrane module flows to the primary concentrate tank, and the product water flows to the product water tank. The antiscalant dosing device is connected to the inlet pipe of the precision filter. The outlet of the first chemical cleaning system is connected to the inlet of the primary reverse osmosis membrane module.

[0009] Furthermore, the two-stage tubular microfiltration pretreatment system includes a third booster pump, a first dosing and mixing tank, a first circulation pump, a second-stage TMF membrane module, a second-stage TMF permeate tank, and a second chemical cleaning system. The inlet of the third booster pump is connected to the outlet of the first-stage concentrate tank, the outlet of the third booster pump is connected to the inlet of the first dosing and mixing tank, the outlet of the first dosing and mixing tank is connected to the inlet of the first circulation pump, the outlet of the first circulation pump is connected to the inlet of the second-stage TMF membrane module, the permeate outlet of the second-stage TMF membrane module is connected to the inlet of the second-stage TMF permeate tank, the sludge outlet of the second-stage TMF membrane module is connected to the filter press system, and the second chemical cleaning system is connected to the inlet of the second-stage TMF membrane module.

[0010] Furthermore, the secondary reverse osmosis concentration system includes a fourth booster pump, a second security filter, a second booster pump, a secondary reverse osmosis membrane module, a first energy recovery device, and a secondary concentrate tank. The inlet of the fourth booster pump is connected to the outlet of the secondary TMF product water tank, the outlet of the fourth booster pump is connected to the inlet of the second security filter, the outlet of the second security filter is connected to the inlet of the second booster pump, the outlet of the second booster pump is connected to the secondary reverse osmosis membrane module, the concentrate outlet of the secondary reverse osmosis membrane module is connected to the inlet of the secondary concentrate tank, and the product water outlet is connected to the product water tank. The inlet of the first energy recovery device is connected to the concentrate outlet of the secondary reverse osmosis membrane module, and the outlet of the first energy recovery device is connected to the outlet pipeline of the second booster pump.

[0011] Furthermore, the three-stage tubular microfiltration pretreatment system includes a fifth booster pump, a second dosing and mixing tank, a second circulation pump, a secondary TMF membrane module, a tertiary TMF permeate tank, and a third chemical cleaning system. The inlet of the fifth booster pump is connected to the outlet of the secondary concentrate tank, the outlet of the fifth booster pump is connected to the inlet of the second dosing and mixing tank, the outlet of the second dosing and mixing tank is connected to the inlet of the second circulation pump, the outlet of the second circulation pump is connected to the inlet of the secondary TMF membrane module, the permeate outlet of the secondary TMF membrane module is connected to the inlet of the tertiary TMF permeate tank, the sludge outlet of the secondary TMF membrane module is connected to the filter press system, and the third chemical cleaning system is connected to the inlet of the secondary TMF membrane module.

[0012] Furthermore, the three-stage ion exchange pretreatment system includes a sixth booster pump, an ion exchanger, a regeneration device, and a softening water tank. The inlet of the sixth booster pump is connected to the outlet of the three-stage TMF product water tank, the outlet of the sixth booster pump is connected to the inlet of the ion exchanger, the regeneration device is connected to the regeneration inlet of the ion exchanger, the outlet of the ion exchanger is connected to the inlet of the softening water tank, and the drain outlet of the ion exchanger is connected to the filter press system.

[0013] Furthermore, the three-stage concentration reverse osmosis system includes a seventh booster pump, a third security filter, a third booster pump, a three-stage reverse osmosis membrane module, a second energy recovery device, and a three-stage concentrate tank. The inlet of the seventh booster pump is connected to the outlet of the softened water tank, the outlet of the seventh booster pump is connected to the inlet of the third security filter, the outlet of the third security filter is connected to the inlet of the third booster pump, the outlet of the third booster pump is connected to the three-stage reverse osmosis membrane module, the concentrate outlet of the three-stage reverse osmosis membrane module is connected to the inlet of the three-stage concentrate tank, and the product water outlet is connected to the product water tank. The inlet of the second energy recovery device is connected to the concentrate outlet of the three-stage reverse osmosis membrane module, and the outlet of the second energy recovery device is connected to the outlet pipeline of the third booster pump.

[0014] The beneficial effects of this utility model are as follows:

[0015] 1. This utility model uses a three-stage membrane concentration and corresponding pretreatment process. Each stage of concentration will increase the solute concentration to a certain level, and then use it as the feed water for the next stage, which improves the utilization of water resources and ultimately achieves the effective treatment of high-concentration wastewater, maximizing the recycling and utilization of mine water resources.

[0016] 2. Compared with traditional concentration methods, the membrane concentration technology of this utility model has higher separation efficiency and energy utilization rate. It can achieve high-efficiency concentration under lower operating pressure, significantly reduce energy consumption, and can achieve selective separation and concentration, effectively remove harmful substances in wastewater, and improve the quality of effluent.

[0017] 3. This utility model uses a concentrated water reverse osmosis energy recovery device to reduce operating costs and reuse production water. It not only increases the concentration of wastewater and reduces the volume of concentrated water after concentration, thus reducing the load on subsequent treatment equipment, but also ensures the quality of the reused water and improves the stability of the system. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present utility model;

[0019] Figure 2 This is a flowchart of the primary ultrafiltration pretreatment system of this utility model;

[0020] Figure 3 This is a flow chart of the first-stage reverse osmosis concentration system of this utility model;

[0021] Figure 4 This is a flowchart of the two-stage tubular microfiltration pretreatment system of this utility model;

[0022] Figure 5 This is a flow chart of the two-stage reverse osmosis concentration system of this utility model;

[0023] Figure 6 This is a flowchart of the three-stage tubular microfiltration pretreatment system of this utility model;

[0024] Figure 7 This is a flowchart of the three-stage ion exchange pretreatment system of this utility model;

[0025] Figure 8 This is a flow chart of the three-stage concentration reverse osmosis system of this utility model.

[0026] In the picture:

[0027] 1. Primary ultrafiltration pretreatment system; 11. First booster pump; 12. Self-cleaning filter; 13. Ultrafiltration membrane module; 14. Product water tank;

[0028] 2. First-stage reverse osmosis concentration system; 21. Second booster pump; 22. Precision filter; 23. First security filter; 24. First booster pump; 25. First-stage reverse osmosis membrane module; 26. Antiscalant dosing device; 27. First chemical cleaning system; 28. First-stage concentrate tank;

[0029] 3. Two-stage tubular microfiltration pretreatment system; 31. Third booster pump; 32. First dosing and mixing tank; 33. First circulation pump; 34. Second-stage TMF membrane module; 35. Second-stage TMF permeate tank; 36. Second chemical cleaning system;

[0030] 4. Secondary reverse osmosis concentration system; 41. Fourth booster pump; 42. Second security filter; 43. Second booster pump; 44. Secondary reverse osmosis membrane module; 45. First energy recovery device; 46. Secondary concentrate tank;

[0031] 5. Three-stage tubular microfiltration pretreatment system; 51. Fifth booster pump; 52. Second dosing and mixing tank; 53. Second circulation pump; 54. Second-stage TMF membrane module; 55. Third-stage TMF permeate tank; 56. Third chemical cleaning system;

[0032] 6. Three-stage ion exchange pretreatment system; 61. Sixth booster pump; 62. Ion exchanger; 63. Regeneration device; 64. Softened water tank;

[0033] 7. Three-stage concentration reverse osmosis system; 71. Seventh booster pump; 72. Third security filter; 73. Third booster pump; 74. Three-stage reverse osmosis membrane module; 75. Second energy recovery device; 76. Three-stage concentrate tank;

[0034] 8. Concentrated brine tank; 9. Product water tank; 10. Filtration system. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0036] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "horizontal," "inner," "outer," and "one side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] Example 1

[0038] like Figure 1-8 As shown in the figure, this embodiment discloses a multi-stage membrane concentration treatment device for high-salt coal mine wastewater, including a primary ultrafiltration pretreatment system 1, a primary reverse osmosis concentration system 2, a secondary tubular microfiltration pretreatment system 3, a secondary reverse osmosis concentration system 4, a tertiary tubular microfiltration pretreatment system 5, a tertiary ion exchange pretreatment system 6, a tertiary concentration reverse osmosis system 7, a concentrated brine tank 8, a product water tank 9, and a filter press system 10.

[0039] The primary ultrafiltration pretreatment system 1 includes a first booster pump 11, a self-cleaning filter 12, an ultrafiltration membrane module 13, a product water tank 14, various monitoring instruments, and pipeline valves. The raw water, a high-salinity water treated by the mine water treatment system, is pumped by the first booster pump 11 to the self-cleaning filter 12, then enters the ultrafiltration membrane module 13. The product water enters the ultrafiltration product water tank 14, and the concentrate is returned to the mine water treatment system. The ultrafiltration membrane module 13 includes an ultrafiltration membrane and an ultrafiltration frame. The ultrafiltration membrane is installed within the ultrafiltration frame, and the membranes are connected by pipelines. An ultrafiltration inlet and an ultrafiltration product water outlet are provided. After filtration by the ultrafiltration membrane module 13, the effluent turbidity is ≤3 NTU, SDI15 ≤3, and the system recovery rate is ≥95%. Simultaneously, the pH and ORP values ​​of the effluent are adjusted to pH = 7-8 and ORP ≤200 mV.

[0040] The primary reverse osmosis concentration system 2 includes a second booster pump 21, a precision filter 22, a first security filter 23, a first booster pump 24, a primary reverse osmosis membrane module 25, an antiscalant dosing device 26, a first chemical cleaning system 27, a primary concentrate tank 28, monitoring instruments, and piping valves. The influent is ultrafiltration permeate, which is sequentially pumped by the second booster pump 21 to the precision filter 22 and the first security filter 23, then by the first booster pump 24 to the primary reverse osmosis membrane module 25. The reverse osmosis permeate enters the product water tank 9, and the concentrate enters the primary concentrate tank 28. The antiscalant dosing device consists of a metering pump, a storage tank, and delivery piping. The dosing port is located at the inlet of the precision filter 22 to reduce the risk of scaling within the reverse osmosis system. The first chemical cleaning system 27 consists of a cleaning pump, cleaning piping, and a storage tank. When the reverse osmosis system operates at excessively high pressure or the output water decreases, it chemically cleans the reverse osmosis membrane module 25 to extend the membrane's lifespan. Operating pressure is approximately 1 MPa, desalination rate is ≥95%, system recovery rate is ≥75%, and concentrate TDS is 8000~9000 mg / L.

[0041] The two-stage tubular microfiltration pretreatment system 3 includes a third lift pump 31, a first dosing and mixing tank 32, a first circulation pump 33, a second-stage TMF membrane module 34, a second-stage TMF permeate tank 35, a second chemical cleaning system 36, monitoring instruments, and pipeline valves. The influent source is the first-stage reverse osmosis concentrate, which is pumped to the first dosing and mixing tank 32 via the third lift pump 31. After chemical reaction, it is pumped to the second-stage TMF membrane module 34 via the first circulation pump 33. The permeate enters the second-stage TMF permeate tank 35 as the feed water for the second-stage reverse osmosis concentrate. The tubular membrane concentrate is returned to the second-stage TMF membrane module 34, where the concentration reaches dynamic equilibrium. The sediment inside the second-stage TMF membrane module 34 is periodically discharged to the filter press system 10, where it is processed into sludge cake. The second chemical cleaning system 36 consists of a cleaning tank and a cleaning pump, used for cleaning the second-stage TMF membrane module 34. The entire system has a recovery rate ≥98%, and the effluent Ca... 2+ ≤20mg / L, Mg 2+ ≤20mg / L, total silicon ≤20mg / L.

[0042] The secondary reverse osmosis concentration system 4 includes a fourth booster pump 41, a second security filter 42, a second booster pump 43, a secondary reverse osmosis membrane module 44, a first energy recovery device 45, a secondary concentrate tank 46, monitoring instruments, and pipeline valves. The influent water source is the permeate from the secondary tubular microfiltration system. It is pumped to the second security filter 42 via the fourth booster pump 41, and then pressurized by the second booster pump 43 before being concentrated in the secondary reverse osmosis membrane module 44. The inlet of the first energy recovery device 45 is connected to the reverse osmosis concentrate outlet, and the outlet of the first energy recovery device 45 is connected to the outlet pipeline of the second booster pump 43. The residual pressure of the reverse osmosis concentrate pipeline is converted into the secondary reverse osmosis influent pressure, reducing the operating energy consumption of the secondary reverse osmosis concentration system. The reverse osmosis permeate enters the product water tank 9, and the concentrate enters the secondary concentrate tank 46. The operating pressure is approximately 5 MPa, the desalination rate is ≥95%, and the system recovery rate is ≥75%. The concentrate TDS is 30000~40000 mg / L.

[0043] The three-stage tubular microfiltration pretreatment system 5 includes a fifth booster pump 51, a second dosing and mixing tank 52, a second circulation pump 53, a secondary TMF membrane module 54, a tertiary TMF permeate tank 55, a third chemical cleaning system 56, monitoring instruments, and pipeline valves. The influent source is secondary reverse osmosis concentrate, which is pumped to the second dosing and mixing tank 52 via the fifth booster pump 51. After chemical reaction, it is pumped to the secondary TMF membrane module 54 via the second circulation pump 53. The permeate enters the product water tank 9 as the tertiary ion exchange feed water. The tubular membrane concentrate is returned to the concentration tank, where the concentration reaches dynamic equilibrium. It is periodically discharged to the filter press system 10, where it is processed into sludge cake. The third chemical cleaning system 56 consists of a cleaning water tank and a cleaning pump, used for cleaning the secondary TMF membrane module 54. The overall system recovery rate is ≥98%, and the effluent Ca... 2+ ≤20mg / L, Mg 2+ ≤20mg / L, total silicon ≤20mg / L.

[0044] The three-stage ion exchange pretreatment system 6 includes a sixth booster pump 61, an ion exchanger 62, a regeneration device 63, and a softening tank 64. The influent source is the permeate from the three-stage tubular microfiltration system, which is pumped to the ion exchanger by the sixth booster pump 61. The permeate then enters the softening tank 64 as the feed water for the three-stage concentrated reverse osmosis system. When the ion exchanger 62 reaches saturation, the regeneration device 63 removes the Ca adsorbed internally from the filter. 2+ Mg 2+ The wastewater is replaced and discharged into the filter press system 10 along with the wastewater. The overall system recovery rate is ≥95%, and the effluent Ca... 2+ ≤1mg / L, Mg 2+ ≤1mg / L.

[0045] The three-stage concentration reverse osmosis system 7 includes a seventh booster pump 71, a third security filter 72, a third booster pump 73, a three-stage reverse osmosis membrane module 74, a second energy recovery device 75, a three-stage concentrate tank 76, monitoring instruments, and piping valves. The feed water source is the three-stage ion exchange permeate, which is pumped by the seventh booster pump 71 to the third security filter 72, and then pressurized by the third booster pump 73 before being concentrated by the three-stage reverse osmosis membrane module 74. The inlet of the second energy recovery device 75 is connected to the reverse osmosis concentrate outlet, and the outlet of the second energy recovery device 75 is connected to the outlet pipeline of the third booster pump 73. The residual pressure in the reverse osmosis concentrate pipeline is converted into the secondary reverse osmosis feed water pressure, reducing the operating energy consumption of the secondary reverse osmosis concentration. The reverse osmosis permeate enters the product water tank 9, and the concentrate enters the three-stage concentrate tank 76 for evaporation and crystallization. The operating pressure is approximately 10 MPa, the desalination rate is ≥95%, the system recovery rate is ≥55%, and the concentrate TDS is 60000~70000 mg / L.

[0046] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A multi-stage membrane concentration treatment device for coal mine high-salinity wastewater, characterized in that, The system comprises a product water tank, a pressure filtration system, and sequentially connected first-stage ultrafiltration pretreatment system, first-stage reverse osmosis concentration system, second-stage tubular microfiltration pretreatment system, second-stage reverse osmosis concentration system, third-stage tubular microfiltration pretreatment system, third-stage ion exchange pretreatment system, third-stage concentrated reverse osmosis system, and concentrated brine tank, the reverse osmosis water outlets of the first-stage reverse osmosis concentration system, the second-stage reverse osmosis concentration system, and the third-stage concentrated reverse osmosis system are connected with the product water tank, and the sewage outlets of the second-stage tubular microfiltration pretreatment system, the third-stage tubular microfiltration pretreatment system, and the third-stage ion exchange pretreatment system are connected with the pressure filtration system.

2. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 1, characterized in that, The first-stage ultrafiltration pretreatment system comprises a first lifting pump, a self-cleaning filter, an ultrafiltration membrane assembly, and an ultrafiltration water production tank, the inlet of the first lifting pump is connected with the mine water treatment system, the outlet of the first lifting pump is connected with the inlet of the self-cleaning filter, the outlet of the self-cleaning filter is connected with the ultrafiltration membrane assembly, the ultrafiltration membrane assembly is connected with the inlet of the ultrafiltration water production tank, and concentrated water is returned to the mine water treatment system.

3. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 2, characterized in that, The first-stage reverse osmosis concentration system comprises a second lifting pump, a precision filter, a first security filter, a first booster pump, a first-stage reverse osmosis membrane assembly, a scale inhibitor dosing device, a first chemical cleaning system, and a first-stage concentrated water tank, the inlet of the second lifting pump is connected with the outlet of the water production tank of the first-stage ultrafiltration pretreatment system, the outlet of the second lifting pump is connected with the inlet of the precision filter, the outlet of the precision filter is connected with the inlet of the first security filter, the outlet of the security filter is connected with the inlet of the first booster pump, the outlet of the first booster pump is connected with the inlet of the first-stage reverse osmosis membrane assembly, concentrated water of the first-stage reverse osmosis membrane assembly flows to the first-stage concentrated water tank, and water production flows to the product water tank, the scale inhibitor dosing device is connected with the water inlet pipeline of the precision filter, and the outlet of the first chemical cleaning system is connected with the inlet of the first-stage reverse osmosis membrane assembly.

4. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 3, characterized in that, The second-stage tubular microfiltration pretreatment system comprises a third lifting pump, a first dosing and stirring tank, a first circulating pump, a second-stage TMF membrane assembly, a second-stage TMF water production tank, and a second chemical cleaning system, the water inlet of the third lifting pump is connected with the outlet of the first-stage concentrated water tank, the outlet of the third lifting pump is connected with the inlet of the first dosing and stirring tank, the outlet of the first dosing and stirring tank is connected with the inlet of the first circulating pump, the outlet of the first circulating pump is connected with the inlet of the second-stage TMF membrane assembly, the water outlet of the second-stage TMF membrane assembly is connected with the inlet of the second-stage TMF water production tank, the sewage outlet of the second-stage TMF membrane assembly is connected with the pressure filtration system, and the second chemical cleaning system is connected with the inlet of the second-stage TMF membrane assembly.

5. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 4, characterized in that, The secondary reverse osmosis concentration system comprises a fourth lifting pump, a second security filter, a second booster pump, a secondary reverse osmosis membrane assembly, a first energy recovery device and a secondary concentrated water tank, the inlet of the fourth lifting pump is connected with the outlet of the secondary TMF water tank, the outlet of the fourth lifting pump is connected with the inlet of the second security filter, the outlet of the second security filter is connected with the inlet of the second booster pump, the outlet of the second booster pump is connected with the secondary reverse osmosis membrane assembly, the concentrated water outlet of the secondary reverse osmosis membrane assembly is connected with the water inlet of the secondary concentrated water tank, the water outlet is connected with the product water tank, and the inlet of the first energy recovery device is connected with the concentrated water outlet of the secondary reverse osmosis membrane assembly.

6. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 5, characterized in that, The third tubular microfiltration pretreatment system comprises a fifth lifting pump, a second dosing and stirring tank, a second circulating pump, a secondary TMF membrane assembly, a third TMF water tank and a third chemical cleaning system, the water inlet of the fifth lifting pump is connected with the water outlet of the secondary concentrated water tank, the outlet of the fifth lifting pump is connected with the inlet of the second dosing and stirring tank, the outlet of the second dosing and stirring tank is connected with the inlet of the second circulating pump, the outlet of the second circulating pump is connected with the inlet of the secondary TMF membrane assembly, the water inlet of the secondary TMF membrane assembly is connected with the water outlet of the third TMF water tank, the blowdown outlet of the secondary TMF membrane assembly is connected with the filter pressing system, and the third chemical cleaning system is connected with the inlet of the secondary TMF membrane assembly.

7. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 6, characterized in that, The third ion exchange pretreatment system comprises a sixth lifting pump, an ion exchanger, a regeneration device and a softened water tank, the inlet of the sixth lifting pump is connected with the outlet of the third TMF water tank, the outlet of the sixth lifting pump is connected with the inlet of the ion exchanger, the regeneration device is connected with the water inlet of the ion exchanger, the water outlet of the ion exchanger is connected with the water inlet of the softened water tank, and the blowdown outlet of the ion exchanger is connected with the filter pressing system.

8. The coal mine high-salinity wastewater multi-stage membrane concentration treatment device according to claim 7, characterized in that, The third concentrated reverse osmosis system comprises a seventh lifting pump, a third security filter, a third booster pump, a third reverse osmosis membrane assembly, a second energy recovery device and a third concentrated water tank, the inlet of the seventh lifting pump is connected with the outlet of the softened water tank, the outlet of the seventh lifting pump is connected with the inlet of the third security filter, the outlet of the third security filter is connected with the inlet of the third booster pump, the outlet of the third booster pump is connected with the third reverse osmosis membrane assembly, the concentrated water inlet of the third reverse osmosis membrane assembly is connected with the water inlet of the third concentrated water tank, the water outlet is connected with the product water tank, the inlet of the second energy recovery device is connected with the concentrated water outlet of the third reverse osmosis membrane assembly, and the outlet of the second energy recovery device is connected with the outlet pipeline of the third booster pump.

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