Circulating drainage softening treatment system for coal-fired power plant

Abstract

The utility model discloses a circulating drainage softening treatment system for a coal-fired power plant and belongs to the technical field of drainage softening treatment. A water outlet of the fluidized bed device is communicated with a regulating reservoir of the immersed membrane filtration device, a water inlet pump is communicated with the fluidized bed device, a first precipitant storage tank is communicated with a first precipitant dosing pump, a second precipitant storage tank is communicated with a second precipitant dosing pump, and the first precipitant dosing pump and the second precipitant dosing pump are communicated with the fluidized bed device; the carrier storage tank is communicated with the carrier dosing pump, the carrier dosing pump is communicated with the fluidized bed device, the acid storage tank is communicated with the acid dosing pump, the acid dosing pump is communicated with the immersed membrane filtration device, and the immersed membrane filtration device is connected with the water production tank through the water production pump. According to the utility model, the circulating drainage of the coal-fired power plant is subjected to efficient softening and hardness reduction treatment through a pretreatment system in which the induced crystallization fluidized bed device is coupled with the immersed membrane filtration device, so that the standing time of crystallization reaction is shortened, the recycling of calcium carbonate is realized, and the stable effluent turbidity index is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of drainage softening treatment, in particular to a circulating drainage softening treatment system of a coal-fired power plant. Background Art

[0002] The induced crystallization fluidized bed softening device is a new type of softening technology. By adding chemical agents to the water and adjusting the target sediment saturation index, the calcium hardness in the water undergoes a chemical reaction to generate calcium carbonate crystals, which are attached to the surface of the pre-added crystal seeds, thereby reducing the hardness of the water. The traditional softening treatment process usually uses a continuous stirring tank for precipitation reaction. The raw water and the precipitant are fully mixed, and the resulting precipitation is removed by coagulation precipitation. The induced crystallization fluidized bed can also achieve softening and hardness reduction treatment. The chemical precipitation continues to grow on the surface of the carrier. The carrier achieves solid-liquid separation in the fluidized bed device due to gravity. Acid is added to the fluidized bed effluent to adjust the effluent pH. The traditional softening treatment process has a stable treatment effect, but it is difficult to realize the resource utilization of calcium carbonate precipitation. The residence time is long and the area occupied is large. Although the induced crystallization fluidized bed can realize the resource utilization of calcium carbonate, due to its own water quality characteristics and fluctuations, it will cause the proportion of heterogeneous crystallization in the total crystallization to decrease, and produce a large number of fine particles. These fine particles are difficult to separate effectively by gravity and will be carried out of the system with the effluent, resulting in high turbidity of the effluent and affecting the stable operation of subsequent treatment units. Therefore, there is an urgent need for a circulating wastewater softening treatment system for coal-fired power plants to overcome the above-mentioned problems existing in existing water treatment systems. Utility Model Content

[0003] The utility model aims to provide a circulating wastewater softening treatment system for a coal-fired power plant, which is used to solve the problem of unstable effluent turbidity caused by fine crystal particles carried out in a traditional induced crystallization fluidized bed.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is as follows: a circulating wastewater softening treatment system of a coal-fired power plant, comprising a first precipitant storage tank, a second precipitant storage tank, a carrier storage tank, an acid storage tank, a first precipitant dosing pump, a second precipitant dosing pump, a carrier dosing pump, an acid dosing pump, a water inlet pump, a fluidized bed device and an immersed membrane filtration device, wherein the water outlet of the fluidized bed device is connected to a regulating tank of the immersed membrane filtration device;

[0005] The inlet pump is connected to the water inlet of the fluidized bed device. The first precipitant storage tank is connected to the inlet of the first precipitant dosing pump. The second precipitant storage tank is connected to the inlet of the second precipitant dosing pump. The outlets of the first precipitant dosing pump and the second precipitant dosing pump are connected to the chemical inlet of the fluidized bed device. The carrier storage tank is connected to the inlet of the carrier dosing pump. The outlet of the carrier dosing pump is connected to the fluidized bed device. The acid storage tank is connected to the inlet of the acid adding pump. The outlet of the acid adding pump is connected to the regulation tank of the submerged membrane filtration device. The submerged membrane filtration device is connected to the inlet of the water production pump. The outlet of the water production pump is connected to the water production tank.

[0006] Further, the fluidized bed device includes a housing, a reflux pump, a pre-distribution area, a water distribution assembly, a chemical distribution assembly, a reaction area, a clarification area, and an overflow pool. The pre-distribution area, the reaction area, the clarification area, and the overflow pool are sequentially connected from bottom to top in the housing. The water distribution assembly is arranged in the pre-distribution area, and the water inlet is connected to the pre-distribution area. The chemical distribution assembly is arranged in the reaction area, and the chemical distribution assembly is connected to the chemical inlet. The overflow pool is provided with a reflux outlet and a water outlet. The center of the bottom of the pre-distribution area is provided with a reflux inlet. The inlet of the reflux pump is connected to the reflux inlet, and the outlet of the reflux pump is connected to the reflux outlet. The water outlet of the overflow pool is connected to the regulation tank of the submerged membrane filtration device.

[0007] Further, the submerged membrane filtration device includes a regulation tank, a membrane tank, a membrane module, a water production pump, and a water production tank. The regulation tank is connected to the membrane tank through a channel. The membrane module is installed in the membrane tank. The water production pipe of the membrane module is connected to the inlet of the water production pump. The outlet of the water production pump is connected to the water production tank.

[0008] Further, two gears are relatively rotatably installed on the side wall of the reaction area through a wheel shaft. A scraper is provided between each gear and the side wall of the reaction area. Each scraper is fixedly connected to the corresponding wheel shaft. The scraper is slidably attached to the side wall of the reaction area. A groove is opened in the reaction area near the overflow pool. Telescopic motors are respectively installed on the two side walls of the reaction area. A rack is fixed to the telescopic end of each telescopic motor. Each rack is respectively engaged with the corresponding gear. A filter screen is provided at the connection between the reaction area and the overflow pool.

[0009] Further, the perpendicular distance between the axis of the water inlet of the fluidized bed device and the central axis of the fluidized bed device is L, satisfying 0 < L < DL / 3, where DL is the outer diameter of the pre-distribution area.

[0010] Further, the chemical distribution assembly is a perforated coiled pipe; the perforation diameter of the perforated coiled pipe is 1 - 2 mm, and the distance between holes is 5 - 20 cm.

[0011] Further, the reaction area is filled with a fluidizable carrier. A viewing window and a sampling port are provided every 1 m in the reaction area; the fluidizable carrier filled in the reaction area is one or a combination of calcite, garnet sand, quartz sand, fluorite, gypsum, etc.; the particle size of the carrier is 0.08 - 0.3 mm.

[0012] Furthermore, the membrane fibers of the submerged membrane filtration device are made of PVDF material, and the pore size of the membrane fibers is 0.01-0.45 μm; the membrane assembly is provided with aeration to flush the pollutants deposited on the membrane surface.

[0013] The regulating tank of the submerged membrane filtration device is provided with a pH electrode which is linked with an acid adding pump to control the pH of the regulating tank to be 5-8.

[0014] Furthermore, turbidity probes are provided in the overflow tank of the fluidized bed device and the membrane tank of the submerged membrane filtration device.

[0015] Furthermore, stirring paddles are provided in the first precipitant storage tank, the second precipitant storage tank and the carrier storage tank for dissolving the agent and dispersing the carrier particles.

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

[0017] 1. The utility model uses the pretreatment system of the induced crystallization fluidized bed device coupled with the submerged membrane filtration device to efficiently soften and reduce the hardness of the circulating wastewater from the coal-fired power plant, reduce the residence time of the crystallization reaction, realize the resource utilization of calcium carbonate, and ensure a stable effluent turbidity index.

[0018] 2. The utility model has the advantages of high treatment efficiency, stable effluent effect, simple operation and management, and high inorganic salt recovery rate. It realizes automatic control of operations such as reagent addition and particle discharge, greatly reduces the labor intensity of manual labor, and improves the level of safe production. The fluidized bed reactor is designed with low carrier loss rate, good fluidization effect, and good induced crystallization effect. By coupling the fluidized bed device with the submerged ultrafiltration device, the problem of unstable effluent turbidity index is solved. At the same time, the submerged ultrafiltration can avoid frequent cleaning and the system stability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0020] Figure 2 is a schematic diagram of the structure of a fluidized bed apparatus;

[0021] Figure 3 is a cross-sectional view of an immersed membrane filtration device;

[0022] Figure 4 is a side view of the reaction zone of the fluidized bed apparatus;

[0023] Figure 5 It is a cross-sectional view of the reaction zone of the fluidized bed apparatus.

[0024] The names and reference numerals of the components involved in the above drawings are as follows:

[0025] 1. First precipitant storage tank; 2. Second precipitant storage tank; 3. Carrier storage tank; 4. Acid storage tank; 5. First precipitant dosing pump; 6. Second precipitant dosing pump; 7. Carrier dosing pump; 8. Acid dosing pump; 9. Reflux pump; 10. Water inlet pump; 11. Water production pump; 12. Water production tank; 13. Water inlet; 14. Drug inlet; 15. Reflux inlet; 16. Pre-water distribution area; 17. Water distribution assembly; 18. Drug distribution assembly; 19. Reaction area; 20. Clarification area; 21. Reflux outlet; 22. Water outlet; 23. Overflow tank; 24. Fluidized bed device; 25. Immersed membrane filtration device; 26. Telescopic motor; 27. Rack; 28. Gear; 29. ​​Scraper; 30. Filter screen; 31. Regulating tank; 32. Membrane tank; 33. Membrane assembly. DETAILED DESCRIPTION

[0026] The technical solution of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0027] Specific implementation method 1: Figure 1-Figure 5 As shown, this embodiment discloses a circulating wastewater softening treatment system for a coal-fired power plant, comprising a first precipitant storage tank 1, a second precipitant storage tank 2, a carrier storage tank 3, an acid storage tank 4, a first precipitant dosing pump 5, a second precipitant dosing pump 6, a carrier dosing pump 7, an acid dosing pump 8, a water inlet pump 10, a fluidized bed device 24 and an immersed membrane filter device 25, wherein the water outlet 22 of the fluidized bed device 24 is connected to a regulating tank 31 of the immersed membrane filter device 25;

[0028] The water inlet pump 10 is connected to the water inlet 13 of the fluidized bed device 24, the first precipitant storage tank 1 is connected to the inlet of the first precipitant dosing pump 5, the second precipitant storage tank 2 is connected to the inlet of the second precipitant dosing pump 6, the outlets of the first precipitant dosing pump 5 and the second precipitant dosing pump 6 are connected to the inlet 14 of the fluidized bed device 24, the carrier storage tank 3 is connected to the inlet of the carrier dosing pump 7, the outlet of the carrier dosing pump 7 is connected to the fluidized bed device 24, the acid storage tank 4 is connected to the inlet of the acid dosing pump 8, the outlet of the acid dosing pump 8 is connected to the regulating tank 31 of the submerged membrane filtration device 25, the submerged membrane filtration device 25 is connected to the inlet of the water production pump 11, and the outlet of the water production pump 11 is connected to the water production tank 12.

[0029] Further, the fluidized bed device 24 includes a housing, a reflux pump 9, a pre-water distribution area 16, a water distribution assembly 17, a chemical dosing assembly 18, a reaction area 19, a clarification area 20, and an overflow tank 23. Inside the housing, there are successively connected from bottom to top the pre-water distribution area 16, the reaction area 19, the clarification area 20, and the overflow tank 23. The water distribution assembly 17 is arranged in the pre-water distribution area 16, and the water inlet 13 is communicated with the pre-water distribution area 16. The chemical dosing assembly 18 is arranged in the reaction area 19, and the chemical dosing assembly 18 is communicated with the chemical inlet 14. The overflow tank 23 is provided with a reflux outlet 21 and a water outlet 22. At the center of the bottom of the pre-water distribution area 16, there is a reflux inlet 15. The inlet of the reflux pump 9 is communicated with the reflux inlet 15, and the outlet of the reflux pump 9 is communicated with the reflux outlet 21. The water outlet 22 of the overflow tank 23 is communicated with the regulation tank 31 of the submerged membrane filtration device 25.

[0030] Further, the submerged membrane filtration device 25 includes a regulation tank 31, a membrane tank 32, a membrane module 33, a water production pump 11, and a water production tank 12. The regulation tank 31 is communicated with the membrane tank 32 through a channel. The membrane module 33 is installed in the membrane tank 32. The water production pipe of the membrane module 33 is communicated with the inlet of the water production pump 11, and the outlet of the water production pump 11 is communicated with the water production tank 12.

[0031] Further, two gears 28 are relatively rotatably installed on the side wall of the reaction area 19 through a wheel shaft. Between each gear 28 and the side wall of the reaction area 19, there is a scraping plate 29. Each scraping plate 29 is fixedly connected to the corresponding wheel shaft. The scraping plate 29 is slidably attached to the side wall of the reaction area 19. A groove is opened in the reaction area 19 near the overflow tank 23. Telescopic motors 26 are respectively installed on the two side walls of the reaction area 19. The telescopic end of each telescopic motor 26 is fixed with a rack 27. Each rack 27 is respectively engaged with the corresponding gear 28. A filter screen 30 is provided at the connection between the reaction area 19 and the overflow tank 23.

[0032] Further, the vertical distance between the axis of the water inlet 13 of the fluidized bed device 24 and the central axis of the fluidized bed device 24 is L, satisfying 0 < L < DL / 3, where DL is the outer diameter of the pre-water distribution area 16.

[0033] Further, the chemical dosing assembly 18 is a perforated coiled pipe; the perforation diameter of the perforated coiled pipe is 1 - 2 mm, and the distance between holes is 5 - 20 cm.

[0034] Further, the reaction area 19 is filled with a fluidizable carrier. Windows and sampling ports are arranged every 1 m in the reaction area 19; the fluidizable carrier filled in the reaction area 19 is one or a combination of calcite, garnet sand, quartz sand, fluorite, and gypsum; the particle size of the carrier is 0.08 - 0.3 mm.

[0035] Furthermore, the membrane fibers of the submerged membrane filtration device 25 are made of PVDF material, and the pore size of the membrane fibers is 0.01-0.45 μm; the membrane assembly 33 is provided with aeration to flush the pollutants deposited on the membrane surface.

[0036] The regulating tank of the submerged membrane filtration device 25 is provided with a pH electrode, which is linked with the acid adding pump 8 to control the pH of the regulating tank to be 5-8.

[0037] Furthermore, the overflow tank 23 of the fluidized bed device 24 and the membrane tank 32 of the submerged membrane filtration device 25 are provided with turbidity probes.

[0038] Furthermore, stirring paddles are provided in the first precipitant storage tank 1, the second precipitant storage tank 2, and the carrier storage tank 3 for dissolving the agent and dispersing the carrier particles.

[0039] The wastewater to be treated is sent to the fluidized bed device 24 for treatment through the water inlet pump 10. The wastewater enters the fluidized bed device 24 from the water inlet 13 of the pre-distribution area 16, and the water flow is evenly distributed through the water distribution component 17. In the reaction zone 19, the wastewater is mixed with the precipitant sent from the drug distribution component 18 connected to the drug inlet 14 to cause a precipitation reaction. Then the wastewater passes through the clarification zone 20 and finally enters the overflow tank 23. The overflow tank 23 is provided with a reflux outlet 21 and a water outlet 22. The inlet of the reflux pump 9 is connected to the reflux inlet 15, and the outlet of the reflux pump 9 is connected to the reflux outlet 21. The outlet 22 of the overflow tank 23 is connected to the regulating tank 31 of the submerged membrane filtration device 25. The regulating tank 31 is connected to the membrane tank 32 through a channel. The membrane assembly 33 is installed in the membrane tank 32. The water production pipe of the membrane assembly 33 is connected to the inlet of the water production pump 11, and the outlet of the water production pump 11 is connected to the water production tank 12.

[0040] After the reaction is completed, the two telescopic motors 26 are started at the same time to drive the two racks 27 to move, thereby driving the gear 28 meshing with the two racks 27 to drive, thereby driving the scraper 29 to scrape the sediment retained on the bottom surface of the reaction zone 19 into the groove on the bottom surface of the reaction zone 19 to collect the sediment.

[0041] A filter screen 30 is provided at the connection point between the reaction zone 19 and the overflow tank 23 to further prevent sediment from entering the overflow zone 13 and causing high turbidity of the effluent water.

[0042] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent conditions of the claims are included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0043] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A circulating wastewater softening treatment system for a coal-fired power plant, characterized in that: The invention comprises a first precipitant storage tank (1), a second precipitant storage tank (2), a carrier storage tank (3), an acid storage tank (4), a first precipitant dosing pump (5), a second precipitant dosing pump (6), a carrier dosing pump (7), an acid dosing pump (8), a water inlet pump (10), a fluidized bed device (24) and an immersed membrane filtration device (25), wherein the water outlet (22) of the fluidized bed device (24) is connected to a regulating tank (31) of the immersed membrane filtration device (25); The water inlet pump (10) is connected to the water inlet (13) of the fluidized bed device (24); the first precipitant storage tank (1) is connected to the inlet of the first precipitant dosing pump (5); the second precipitant storage tank (2) is connected to the inlet of the second precipitant dosing pump (6); the outlets of the first precipitant dosing pump (5) and the second precipitant dosing pump (6) are connected to the drug inlet (14) of the fluidized bed device (24); the carrier storage tank (3) is connected to the inlet of the carrier dosing pump (7); the outlet of the carrier dosing pump (7) is connected to the fluidized bed device (24); the acid storage tank (4) is connected to the inlet of the acid dosing pump (8); the outlet of the acid dosing pump (8) is connected to the regulating tank (31) of the submerged membrane filtration device (25); the submerged membrane filtration device (25) is connected to the inlet of the water production pump (11); and the outlet of the water production pump (11) is connected to the water production tank (12).

2. A circulating wastewater softening treatment system for a coal-fired power plant according to claim 1, characterized in that: The fluidized bed device (24) comprises a shell, a reflux pump (9), a pre-water distribution area (16), a water distribution assembly (17), a medicine distribution assembly (18), a reaction area (19), a clarification area (20) and an overflow tank (23). The shell is provided with the pre-water distribution area (16), the reaction area (19), the clarification area (20) and the overflow tank (23) which are sequentially connected from bottom to top. The water distribution assembly (17) is arranged in the pre-water distribution area (16). The water inlet (13) is connected to the pre-water distribution area (16). The medicine distribution assembly (18) is connected to the reaction area (19), and the medicine distribution assembly (20) is connected to the reaction area (19). 18) is arranged in the reaction zone (19), the drug distribution component (18) is connected to the drug inlet (14), the overflow tank (23) is provided with a reflux outlet (21) and a water outlet (22), a reflux inlet (15) is provided at the bottom center of the pre-water distribution area (16), the inlet of the reflux pump (9) is connected to the reflux inlet (15), the outlet of the reflux pump (9) is connected to the reflux outlet (21), and the water outlet (22) of the overflow tank (23) is connected to the regulating tank (31) of the submerged membrane filtration device (25).

3. A coal-fired power plant circulating wastewater softening treatment system according to claim 2, characterized in that: The submerged membrane filtration device (25) comprises a regulating tank (31), a membrane tank (32), a membrane assembly (33), a water production pump (11) and a water production tank (12); the regulating tank (31) is connected to the membrane tank (32) via a channel; the membrane assembly (33) is installed in the membrane tank (32); the water production pipe of the membrane assembly (33) is connected to the inlet of the water production pump (11); and the outlet of the water production pump (11) is connected to the water production tank (12).

4. A coal-fired power plant circulating wastewater softening treatment system according to claim 3, characterized in that: On the side wall of the reaction zone (19), two gears (28) are relatively rotatably mounted through axles. A scraper (29) is provided between each gear (28) and the side wall of the reaction zone (19). Each scraper (29) is fixedly connected to the corresponding axle. The scraper (29) is in sliding fit with the side wall of the reaction zone (19). A groove is formed in the reaction zone (19) near the overflow pool (23). Telescopic motors (26) are respectively mounted on the two side walls of the reaction zone (19). A rack (27) is fixed to the telescopic end of each telescopic motor (26). Each rack (27) is respectively meshed with the corresponding gear (28). A filter screen (30) is provided at the connection between the reaction zone (19) and the overflow pool (23).

5. A coal-fired power plant circulating wastewater softening treatment system according to claim 4, characterized in that: The perpendicular distance between the axis of the water inlet (13) of the fluidized bed device (24) and the central axis of the fluidized bed device (24) is L, satisfying 0 < L < DL / 3, where DL is the outer diameter of the pre-distribution zone (16).

6. A coal-fired power plant circulating wastewater softening treatment system according to claim 5, characterized in that: The chemical dosing assembly (18) is a perforated coiled pipe; the perforation diameter of the perforated coiled pipe is 1 - 2 mm, and the distance between holes is 5 - 20 cm.

7. A coal-fired power plant circulating wastewater softening treatment system according to claim 6, characterized in that: The reaction zone (19) is filled with a fluidizable carrier. Windows and sampling ports are arranged every 1 m in the reaction zone (19); the fluidizable carrier filled in the reaction zone (19) is one or a combination of calcite, garnet sand, quartz sand, fluorite, gypsum, etc.; the particle size of the carrier is 0.08 - 0.3 mm.

8. A coal-fired power plant circulating wastewater softening treatment system according to claim 1, characterized in that: The membrane filaments of the submerged membrane filtration device (25) are made of PVDF material, and the membrane filament pore diameter is 0.01 - 0.45 μm; aeration is provided in the membrane module (33) to wash the pollutants deposited on the membrane surface.

9. A coal-fired power plant circulating wastewater softening treatment system according to claim 8, characterized in that: Turbidity probes are arranged in the overflow pool (23) of the fluidized bed device (24) and the membrane pool (32) of the submerged membrane filtration device (25).

10. A circulating wastewater softening treatment system for a coal-fired power plant according to claim 1, characterized in that: Stirring paddles are arranged in the first precipitant storage tank (1), the second precipitant storage tank (2), and the carrier storage tank (3) for dissolving the chemicals and dispersing the carrier particles.

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