Crystallization defluorination fluidized bed coupling defluorination system for fluorine-containing wastewater

Abstract

The utility model discloses a fluorine removal system coupled with a crystallization fluorine removal fluidized bed for fluorine-containing wastewater, which belongs to the technical field of fluorine-containing wastewater purification and comprises a raw water tank, the crystallization fluorine removal fluidized bed, a coagulation reaction tank and a gravity settling tank which are arranged according to a process flow, the raw water tank is communicated with an inlet end of the crystallization defluorination fluidized bed through a water inlet lifting pump, an upper water outlet of the crystallization defluorination fluidized bed is communicated with an upper water inlet of the coagulation reaction tank through a conveying pipeline, and a pipeline mixer is mounted in the middle of the conveying pipeline; a water outlet is formed in the upper part of the coagulation reaction tank and is communicated with a water inlet in the upper part of the gravity settling tank; the crystallization defluorination fluidized bed is provided with an induced crystallization dosing device, the pipeline mixer is provided with a deep defluorination dosing device, and the coagulation reaction tank is provided with a PAC / PAM dosing device. According to the utility model, a crystallization defluorination fluidized bed technology and a deep defluorination technology are coupled and have complementary advantages, so that the sludge yield can be effectively reduced, the treatment cost is reduced, and a stable treatment result is achieved.

Description

Technical Field

[0001] This utility model relates to the field of fluoride-containing wastewater purification technology, and in particular to a crystallization defluorination fluidized bed coupled defluorination system for fluoride-containing wastewater. Background Technology

[0002] Fluoride-containing wastewater is a common type of industrial wastewater, involving chemical industries such as metal smelting, steel, cement, aluminum electrolysis, ceramics, pharmaceuticals, and semiconductors. In recent years, the rapid development of industry has led to an increase in the production of fluoride-containing wastewater, with increasingly complex water quality and greater difficulty in treatment, causing increasingly serious damage to the environment.

[0003] Currently, the most common method for treating fluoride-containing wastewater is chemical precipitation, which involves adding calcium-containing compounds such as lime or lime milk to the wastewater to reduce the fluoride content. 2+ Ions and F in wastewater - The ions are converted into CaF2 and removed as a precipitate. This method is affected by Ca... 2+ A low concentration can lead to excessive dosage of the reagent, resulting in a high amount of suspended solids in the water, a large sludge production, and a high requirement for Ca2+. 2+ With F - Sufficient contact time is required to achieve satisfactory defluoridation results, and the fluoride content in the treated wastewater is difficult to consistently meet standards. Other defluoridation methods, such as adsorption and reverse osmosis, have drawbacks such as high treatment costs, poor treatment efficiency, and easy membrane clogging. Utility Model Content

[0004] Technical problem solved: To address the technical problems existing in the prior art, this utility model provides a crystallization fluidized bed coupled defluorination system for fluoride-containing wastewater. It couples crystallization fluidized bed defluorination technology with deep defluorination technology, complementing each other's advantages. This can effectively reduce sludge production and treatment costs while achieving stable treatment results. At the same time, the crystals discharged from the crystallization fluidized bed defluorination are high-purity fluorite, which is one of the raw materials for generating hydrofluoric acid and has high recycling value.

[0005] Technical solution: The present invention provides a crystallization defluorination fluidized bed coupled defluorination system for fluoride-containing wastewater, comprising a raw water tank, a crystallization defluorination fluidized bed, a coagulation reaction tank, and a gravity settling tank arranged according to the process flow.

[0006] The raw water tank is connected to the inlet of the crystallization defluorination fluidized bed via an inlet booster pump. The upper outlet of the crystallization defluorination fluidized bed is connected to the upper inlet of the coagulation reaction tank via a conveying pipe, and a pipe mixer is installed in the middle of the conveying pipe. The upper part of the coagulation reaction tank is provided with an outlet that is connected to the upper inlet of the gravity settling tank.

[0007] The crystallization defluorination fluidized bed is equipped with a dosing device for inducing crystallization by adding CaCl2 and NaOH reagents; the pipeline mixer is equipped with a deep defluorination dosing device; and the coagulation reaction tank is equipped with a PAC / PAM dosing device.

[0008] Preferably, the outlet of the water inlet booster pump is connected to a bypass channel to return to the raw water tank, and an electric ball valve is installed in the bypass channel; a level gauge is installed in the raw water tank, and the level gauge is interlocked with the electric ball valve.

[0009] Preferably, the crystallization defluorination fluidized bed has an outlet at the upper part of its sidewall and a crystal discharge outlet at the lower part; the crystallization defluorination fluidized bed has a reflux outlet and a reflux inlet at the upper and lower parts of its sidewall, the reflux outlet is connected to the reflux inlet through a reflux pipe, and a reflux pump is connected in the reflux pipe.

[0010] Preferably, the bottom end of the crystallization defluorination fluidized bed is provided with a CaCl2 dosing port and a NaOH dosing port;

[0011] The induced crystallization dosing device includes a CaCl2 storage tank and a CaCl2 dosing pump connected to the CaCl2 storage tank, a NaOH storage tank and a NaOH dosing pump connected to the NaOH storage tank, the CaCl2 dosing port being connected to the CaCl2 dosing pump outlet, and the NaOH dosing port being connected to the NaOH dosing pump outlet; an online pH meter is installed at the top of the crystallization defluorination fluidized bed, and the online pH meter is interlocked with the NaOH dosing pump for control.

[0012] Preferably, the deep defluorination dosing device includes a deep defluorination agent storage tank and a deep defluorination agent dosing pump connected to the deep defluorination agent storage tank, and the outlet of the deep defluorination agent dosing pump is connected to the dosing inlet of the pipeline mixer.

[0013] Preferably, the coagulation reaction tank is divided into a coagulation tank and a flocculation tank by a partition, and the bottom of the partition is provided with a channel connecting the coagulation tank and the flocculation tank. Both the coagulation tank and the flocculation tank are equipped with a stirrer.

[0014] Preferably, both the coagulation tank and the flocculation tank have a dosing port on their sidewalls;

[0015] The PAC / PAM dosing device includes a PAC storage tank and a PAC dosing pump connected to the PAC storage tank, a PAM storage tank and a PAM dosing pump connected to the PAM storage tank, the outlet of the PAC dosing pump is connected to the dosing port of the coagulation tank, and the outlet of the PAM dosing pump is connected to the dosing port of the flocculation tank.

[0016] Preferably, the gravity settling tank has an outlet at the top and a sludge discharge outlet at the bottom.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] 1. This utility model couples crystallization defluorination fluidized bed technology and deep defluorination technology, complementing each other's advantages, which can effectively reduce sludge production, reduce treatment costs, and achieve stable treatment results.

[0019] 2. This system uses a crystallization fluidized bed for defluorination pretreatment. By adding CaCl2 and NaOH reagents to the crystallization fluidized bed, the generated CaF2 crystallizes and grows in the filled induced crystal nuclei. After reaching a certain diameter, it is discharged. This system has advantages such as low dosage and low sludge production. Moreover, the discharged crystals are high-purity fluorite, which is one of the raw materials for the production of hydrofluoric acid and has high recycling value.

[0020] 3. This crystallization fluidized bed coupled with deep defluorination technology greatly reduces the dosage of deep defluorination agents and the production of sludge. The deep defluorination can also remove fluoride ions that could not be treated in the crystallization fluidized bed, and the effluent fluoride concentration can be stably reduced to 1.0 mg / L. Compared with traditional chemical precipitation defluorination, the cost per ton of water treated by the defluorination system of this invention is greatly reduced, and its advantages are particularly obvious for medium and high concentration fluoride-containing wastewater.

[0021] 4. The defluoridation system of the present invention has a high degree of automation. By adding a bypass passage for the return flow of the inlet pipe to the raw water tank, it can automatically maintain the stability of the liquid level in the raw water tank through instrument interlocking when the incoming water is unstable, ensuring that the crystallization defluoridation fluidized bed does not stop. Through the interlocking of the online pH meter at the top of the crystallization defluoridation fluidized bed tower and the NaOH dosing pump, the NaOH dosage can be automatically adjusted according to the pH change.

[0022] This invention also has other beneficial effects, which are described in the embodiments section of the specification and will not be repeated here. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the crystallization defluorination fluidized bed coupled defluorination system of this utility model;

[0024] Figure 2 for Figure 1 Block diagram of a crystallization-based defluorination fluidized bed coupled defluorination system;

[0025] Figure 3 for Figure 1 Plan view of the layout of the crystallization defluorination fluidized bed coupled defluorination system.

[0026] Attached reference numerals: 1. Raw water tank; 2. Inlet booster pump; 3. Crystallization defluoridation fluidized bed; 4. Return pump; 5. Pipeline mixer; 6. Coagulation tank; 7. Flocculation tank; 8. Gravity settling tank; 9. PAM dosing pump; 10. PAM storage tank; 11. PAC dosing pump; 12. PAC storage tank; 13. Deep defluoridation agent dosing pump; 14. Deep defluoridation agent storage tank; 15. CaCl2 dosing pump; 16. CaCl2 storage tank; 17. NaOH dosing pump; 18. NaOH storage tank; 19. Electric ball valve; 20. Level gauge; 21. Online pH meter; 22. Induced crystallization dosing device; 23. Deep defluoridation dosing device; 24. PAC / PAM dosing device; 25. Coagulation reaction tank. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the following will be described in conjunction with the accompanying drawings. Figures 1-3 The technical solutions of the embodiments of this utility model are clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model are within the protection scope of this utility model.

[0028] like Figures 1-3 As shown, this utility model provides a crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater, comprising a raw water tank 1, a crystallization-based fluidized bed 3, a coagulation reaction tank 25, and a gravity settling tank 8 arranged according to the process flow. The raw water tank 1 is connected to the inlet of the crystallization-based fluidized bed 3 via an inlet booster pump 2. The upper outlet of the crystallization-based fluidized bed 3 is connected to the upper inlet of the coagulation reaction tank 25 via a conveying pipe, and a pipe mixer 5 is installed in the middle of the conveying pipe. The upper outlet of the coagulation reaction tank 25 is connected to the upper inlet of the gravity settling tank 8. The crystallization-based fluidized bed 3 is equipped with an induction crystallization dosing device 22 for adding CaCl2 and NaOH reagents; the pipe mixer 5 is equipped with a deep defluorination dosing device 23; and the coagulation reaction tank 25 is equipped with a PAC / PAM dosing device 24. This invention couples crystallization defluorination fluidized bed 3 technology with deep defluorination technology, complementing each other's advantages. It can effectively reduce sludge production and treatment costs while achieving stable treatment results. The defluorination system uses crystallization defluorination fluidized bed 3 for defluorination pretreatment. By adding CaCl2 and NaOH reagents into the crystallization defluorination fluidized bed 3, the generated CaF2 crystallizes and grows in the filled induced crystal nuclei, and is discharged after reaching a certain diameter. This system has advantages such as low dosage and low sludge production, and the discharged crystals are high-purity fluorite, which is one of the raw materials for generating hydrofluoric acid and has high recycling value.

[0029] like Figure 1As shown, the outlet of the inlet booster pump 2 is connected to a bypass pipe that returns to the raw water tank 1. An electric ball valve 19 is installed in the bypass pipe. A level gauge 20 is installed in the raw water tank 1, and the level gauge 20 is interlocked with the electric ball valve 19. The defluorination system of this invention has a high degree of automation. By adding a bypass pipe for the return of the inlet water to the raw water tank 1, the liquid level in the raw water tank 1 can be automatically maintained through instrument interlocking when the incoming water is unstable. This achieves the balance of the liquid level in the raw water tank 1, ensuring continuous water intake and operation of the crystallization defluorination fluidized bed 3, and ensuring that the crystallization defluorination fluidized bed 3 does not stop.

[0030] like Figure 1 As shown, the upper part of the sidewall of the crystallization defluorination fluidized bed 3 is provided with a water outlet, and the lower part is provided with a crystal discharge outlet. The upper and lower parts of the sidewall of the crystallization defluorination fluidized bed 3 are provided with a reflux outlet and a reflux inlet. The reflux outlet is connected to the reflux inlet through a reflux pipe, and a reflux pump 4 is connected to the reflux pipe to achieve fluid circulation and fluidization within the crystallization defluorination fluidized bed 3, thereby improving the Ca2+ efficiency. 2+ With F - The contact time is increased to improve the defluorination efficiency of the crystallization defluorination fluidized bed 3.

[0031] like Figure 1 As shown, the bottom of the crystallization defluorination fluidized bed 3 is provided with a CaCl2 dosing port and a NaOH dosing port; the crystallization induction dosing device 22 includes a CaCl2 storage tank 16 and a CaCl2 dosing pump 15 connected to the CaCl2 storage tank 16, a NaOH storage tank 18 and a NaOH dosing pump 17 connected to the NaOH storage tank 18, the CaCl2 dosing port is connected to the outlet of the CaCl2 dosing pump 15, and the NaOH dosing port is connected to the outlet of the NaOH dosing pump 17; the top of the crystallization defluorination fluidized bed 3 is provided with an online pH meter 21, which is interlocked with the NaOH dosing pump 17. This system employs a crystallization-based fluidized bed 3 for pretreatment to remove fluoride. By adding CaCl2 and NaOH to the fluidized bed 3, the generated CaF2 crystallizes and grows within the filled induced crystal nuclei, eventually being discharged after reaching a certain diameter. This system offers advantages such as low dosage and low sludge production. Furthermore, the discharged crystals are high-purity fluorite, a raw material for hydrofluoric acid production, possessing high recycling value. The defluorination system utilizes an online pH meter 21 at the top of the fluidized bed 3 and a NaOH dosing pump 17 for interlocking. This ensures that the pump stops when the pH exceeds a set value and starts when the pH falls below the set value, automatically adjusting the NaOH dosage based on pH changes.

[0032] like Figure 1As shown, the deep defluoridation dosing device 23 includes a deep defluoridating agent storage tank 14 and a deep defluoridating agent dosing pump 13 connected to the deep defluoridating agent storage tank 14. The outlet of the deep defluoridating agent dosing pump 13 is connected to the dosing inlet of the pipeline mixer 5. This crystallization fluidized bed coupled with deep defluoridation technology greatly reduces the amount of deep defluoridating agent required and the amount of sludge produced. The deep defluoridation can also remove fluoride ions that could not be treated in the crystallization defluoridation fluidized bed 3 a second time, and the effluent fluoride ion concentration can be stably reduced to 1.0 mg / L. Compared with traditional chemical precipitation defluoridation, the cost per ton of water treated by the defluoridation system of this invention is greatly reduced, and its advantages are particularly obvious for medium and high concentration fluoride-containing wastewater.

[0033] like Figure 1 and Figure 3 As shown, the coagulation reaction tank 25 is divided into a coagulation tank 6 and a flocculation tank 7 by a partition. The bottom of the partition has a channel connecting the coagulation tank 6 and the flocculation tank 7. Both the coagulation tank 6 and the flocculation tank 7 are equipped with a stirrer. Both the coagulation tank 6 and the flocculation tank 7 have a dosing port on their side walls. The PAC / PAM dosing device 24 includes a PAC storage tank 12 and a PAC dosing pump 11 connected to the PAC storage tank 12, a PAM storage tank 10 and a PAM dosing pump 9 connected to the PAM storage tank 10. The outlet of the PAC dosing pump 11 is connected to the dosing port of the coagulation tank 6, and the outlet of the PAM dosing pump 9 is connected to the dosing port of the flocculation tank 7.

[0034] like Figure 1 As shown, the gravity settling tank 8 is equipped with an outlet at the top, and qualified effluent is discharged to a designated location through a pipe connected to the outlet; the gravity settling tank 8 is equipped with a sludge discharge outlet at the bottom, and gravity-sedied sludge is discharged to a designated location through a pipe connected to the sludge discharge outlet.

[0035] The above are preferred embodiments of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A crystallization-based fluidized bed coupled defluorination system for defluorination of fluoride-containing wastewater, characterized in that, It includes a raw water tank (1), a crystallization defluorination fluidized bed (3), a coagulation reaction tank (25), and a gravity settling tank (8) set up according to the process flow; The raw water tank (1) is connected to the inlet end of the crystallization defluorination fluidized bed (3) via the inlet booster pump (2). The upper outlet of the crystallization defluorination fluidized bed (3) is connected to the upper inlet of the coagulation reaction tank (25) via a conveying pipe, and a pipe mixer (5) is installed in the middle of the conveying pipe. The upper part of the coagulation reaction tank (25) is provided with an outlet that is connected to the upper inlet of the gravity settling tank (8). The crystallization defluorination fluidized bed (3) is equipped with an induction crystallization dosing device (22) for adding CaCl2 and NaOH reagents; the pipeline mixer (5) is equipped with a deep defluorination dosing device (23); and the coagulation reaction tank (25) is equipped with a PAC / PAM dosing device (24).

2. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 1, characterized in that, The outlet of the water inlet booster pump (2) is connected to a bypass channel to return to the raw water tank (1). An electric ball valve (19) is installed in the bypass channel. A level gauge (20) is installed in the raw water tank (1). The level gauge (20) is interlocked with the electric ball valve (19).

3. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 1, characterized in that, The upper part of the side wall of the crystallization defluorination fluidized bed (3) is provided with a water outlet and the lower part is provided with a crystal discharge outlet; the upper and lower parts of the side wall of the crystallization defluorination fluidized bed (3) are provided with a reflux outlet and a reflux inlet, the reflux outlet is connected to the reflux inlet through a reflux pipe, and a reflux pump (4) is connected in the reflux pipe.

4. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 3, characterized in that, The bottom end of the crystallization defluorination fluidized bed (3) is provided with a CaCl2 dosing port and a NaOH dosing port; The induced crystallization dosing device (22) includes a CaCl2 storage tank (16) and a CaCl2 dosing pump (15) connected to the CaCl2 storage tank (16), a NaOH storage tank (18) and a NaOH dosing pump (17) connected to the NaOH storage tank (18). The CaCl2 dosing port is connected to the outlet of the CaCl2 dosing pump (15), and the NaOH dosing port is connected to the outlet of the NaOH dosing pump (17). An online pH meter (21) is provided at the top of the crystallization defluorination fluidized bed (3), and the online pH meter (21) is interlocked with the NaOH dosing pump (17).

5. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to any one of claims 1 to 4, characterized in that, The deep defluorination dosing device (23) includes a deep defluorination agent storage tank (14) and a deep defluorination agent dosing pump (13) connected to the deep defluorination agent storage tank (14). The outlet of the deep defluorination agent dosing pump (13) is connected to the dosing inlet of the pipeline mixer (5).

6. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 5, characterized in that, The coagulation reaction tank (25) is divided into a coagulation tank (6) and a flocculation tank (7) by a partition. The bottom of the partition is provided with a channel connecting the coagulation tank (6) and the flocculation tank (7). Both the coagulation tank (6) and the flocculation tank (7) are equipped with a stirrer.

7. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 6, characterized in that, Both the coagulation tank (6) and the flocculation tank (7) have a dosing port on their side walls; The PAC / PAM dosing device (24) includes a PAC storage tank (12) and a PAC dosing pump (11) connected to the PAC storage tank (12), a PAM storage tank (10) and a PAM dosing pump (9) connected to the PAM storage tank (10). The outlet of the PAC dosing pump (11) is connected to the dosing port of the coagulation tank (6), and the outlet of the PAM dosing pump (9) is connected to the dosing port of the flocculation tank (7).

8. The crystallization-based fluidized bed coupled defluorination system for fluoride-containing wastewater according to claim 5, characterized in that, The gravity settling tank (8) has an outlet at the top and a sludge discharge port at the bottom.

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