Treatment system for fire-fighting wastewater of lithium iron phosphate battery energy storage power station

Abstract

The invention belongs to the technical field of fire-fighting wastewater treatment, and particularly relates to a treatment system for fire-fighting wastewater of a lithium iron phosphate battery energy storage power station. The system comprises a grating adjusting tank, a flocculation sedimentation tank, an intermediate adjusting tank, a catalytic wet oxidation reactor, an anaerobic reactor, an aerobic-anoxic reactor, a fluorine and phosphorus removal reaction sedimentation tank, an ozone oxidation reactor, an adsorption tower, a filter tank and a disinfection tank which are arranged in sequence. And the treated fire-fighting wastewater of the lithium iron phosphate battery energy storage power station reaches the discharge standard.

Description

Technical Field

[0001] This invention belongs to the field of fire-fighting wastewater treatment technology, specifically relating to a treatment system for fire-fighting wastewater from a lithium iron phosphate battery energy storage power station. Background Technology

[0002] In recent years, with the rapid development of energy storage power stations, more and more lithium iron phosphate (LFP) battery energy storage power stations have been built. When LFP batteries experience thermal runaway, they are prone to fire. When the detection and alarm system in a single battery compartment of a LFP battery energy storage power station detects thermal runaway, the perfluorohexanone (PFH) gas fire suppression system is activated to provide cluster-level and compartment-level total flooding protection. If the PPH fire suppression system fails to extinguish the initial fire in time, resulting in a large-scale fire within the compartment (multiple individual batteries, or even multiple battery modules or battery clusters ignited), the amount of PPH extinguishing agent will be insufficient, making the fire in the energy storage battery compartment uncontrollable. At this time, the water sprinkler fire suppression system is activated to cool and extinguish the fire throughout the compartment as a backup measure. If a fire in a single compartment shows a tendency to spread to other compartments, outdoor fire hydrants in the battery compartment area can also be activated to ensure the safety of other battery compartments.

[0003] After the fire in the battery compartment is extinguished, the lithium salt and electrolyte of the lithium iron phosphate battery will undergo hydrolysis and decomposition, producing fluorine-, arsenic-, and phosphorus-containing compounds. The fire extinguishing agent perfluorohexanone will also undergo hydrolysis and pyrolysis, producing harmful substances such as hydrogen fluoride and perfluoropropionic acid. If these harmful substances are allowed to enter the natural environment, they will cause serious and even irreversible pollution to water bodies and soil. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a treatment system for fire-fighting wastewater from lithium iron phosphate battery energy storage power stations, so that the fire-fighting wastewater from lithium iron phosphate battery energy storage power stations can meet the discharge standards after treatment.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a treatment system for fire-fighting wastewater of lithium iron phosphate battery energy storage power station, comprising a bar regulating tank, a flocculation sedimentation tank, an intermediate regulating tank, a catalytic wet oxidation reactor, an anaerobic reactor, an aerobic-anoxic reactor, a fluoride and phosphorus removal reaction sedimentation tank, an ozone oxidation reactor, an adsorption tower, a filter tank and a disinfection tank arranged in sequence. The outlet of the bar screen equalization tank is connected to the inlet of the flocculation sedimentation tank via a first drainage pipe; the outlet of the flocculation sedimentation tank is connected to the inlet of the intermediate equalization tank via a second drainage pipe; the outlet of the intermediate equalization tank is connected to the inlet of the catalytic wet oxidation reactor via a third drainage pipe; the outlet of the catalytic wet oxidation reactor is connected to the inlet of the anaerobic reactor via a fourth drainage pipe; and the outlet of the anaerobic reactor is connected to the inlet of the aerobic-anoxic reactor via a fifth drainage pipe. The outlet of the aerobic-anoxic reactor is connected to the inlet of the fluoride and phosphorus removal reaction sedimentation tank via a sixth drainage pipe; the outlet of the fluoride and phosphorus removal reaction sedimentation tank is connected to the inlet of the ozone oxidation reactor via a seventh drainage pipe; the outlet of the ozone oxidation reactor is connected to the inlet of the adsorption tower via an eighth drainage pipe; the outlet of the adsorption tower is connected to the inlet of the filtration tank via a ninth drainage pipe; and the outlet of the filtration tank is connected to the inlet of the disinfection tank via a tenth drainage pipe.

[0006] Furthermore, it also includes sludge thickening tanks and filter presses; The sludge outlet of the flocculation sedimentation tank is connected to the sludge inlet of the sludge thickening tank via a first sludge pipe; the sludge outlet of the anaerobic reactor is connected to the sludge inlet of the sludge thickening tank via a second sludge pipe; the sludge outlet of the aerobic-anoxic reactor is connected to the sludge inlet of the sludge thickening tank via a third sludge pipe; the sludge outlet of the fluoride and phosphorus removal reaction sedimentation tank is connected to the sludge inlet of the sludge thickening tank via a fourth sludge pipe; the sludge outlet of the filtration tank is connected to the sludge inlet of the sludge thickening tank via a fifth sludge pipe; and the sludge outlet of the sludge thickening tank is connected to the sludge inlet of the filter press via a sixth sludge pipe.

[0007] Furthermore, the flocculation sedimentation tank is an inclined plate flocculation sedimentation tank.

[0008] Furthermore, the anaerobic reactor is a UASB anaerobic reactor.

[0009] Furthermore, the adsorption tower is a biochar adsorption tower.

[0010] Furthermore, the filtration pool is a sand filter.

[0011] Furthermore, the sludge thickening tank is a gravity thickening tank.

[0012] Furthermore, the filter press is a plate and frame filter press.

[0013] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a treatment system for fire-fighting wastewater from lithium iron phosphate battery energy storage power stations, enabling the treated wastewater to meet discharge standards. It considers not only the wastewater generated by lithium salts and electrolytes from lithium iron phosphate batteries, but also the impact of perfluorohexanone gas extinguishing agents commonly used in lithium iron phosphate battery compartments on the quality of the fire-fighting wastewater, making the treatment system highly targeted. Addressing the problems of poor biodegradability and ineffective traditional biological treatment methods for fire-fighting wastewater, the catalytic wet oxidation reactor, anaerobic reactor, and aerobic-anoxic reactor employed improve the treatment effect of fire-fighting wastewater and also offer good economic benefits. Furthermore, it achieves compliant discharge of fire-fighting wastewater and safe disposal of sludge, completely eliminating the risk of secondary pollution from fire-fighting wastewater. Attached Figure Description

[0014] Figure 1 This is the overall flowchart of the present invention; Attached diagram labels: 1-Grid equalization tank, 2-Flocculation sedimentation tank, 3-Intermediate equalization tank, 4-Catalytic wet oxidation reactor, 5-Anaerobic reactor, 6-Aerobic-anoxic reactor, 7-Fluoride and phosphorus removal reaction sedimentation tank, 8-Ozone oxidation reactor, 9-Adsorption tower, 10-Filter tank, 11-Disinfection tank, 12-Sludge thickening tank, 13-Filter press. Detailed Implementation

[0015] The following is in conjunction with the appendix Figure 1 The invention is further illustrated by the examples. COD, as used below, refers to Chemical Oxygen Demand, an important indicator for measuring the content of organic pollutants in water bodies. It reflects the total amount of organic matter and reducing inorganic substances in the water.

[0016] The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station includes, in sequence, a bar screen equalization tank 1, a flocculation sedimentation tank 2, an intermediate equalization tank 3, a catalytic wet oxidation reactor 4, an anaerobic reactor 5, an aerobic-anoxic reactor 6, a fluoride and phosphorus removal reaction sedimentation tank 7, an ozone oxidation reactor 8, an adsorption tower 9, a filtration tank 10, and a disinfection tank 11.

[0017] The outlet of the bar screen equalization tank 1 is connected to the inlet of the flocculation sedimentation tank 2 via a first drainage pipe. The outlet of the flocculation sedimentation tank 2 is connected to the inlet of the intermediate equalization tank 3 via a second drainage pipe. The outlet of the intermediate equalization tank 3 is connected to the inlet of the catalytic wet oxidation reactor 4 via a third drainage pipe. The outlet of the catalytic wet oxidation reactor 4 is connected to the inlet of the anaerobic reactor 5 via a fourth drainage pipe. The outlet of the anaerobic reactor 5 is connected to the inlet of the aerobic-anoxic reactor 6 via a fifth drainage pipe. The outlet of the aerobic-anoxic reactor 6 is connected to the inlet of the defluorination and phosphorus removal reaction sedimentation tank 7 through a sixth drainage pipe. The outlet of the defluorination and phosphorus removal reaction sedimentation tank 7 is connected to the inlet of the ozone oxidation reactor 8 through a seventh drainage pipe. The outlet of the ozone oxidation reactor 8 is connected to the inlet of the adsorption tower 9 through an eighth drainage pipe. The outlet of the adsorption tower 9 is connected to the inlet of the filter tank 10 through a ninth drainage pipe. The outlet of the filter tank 10 is connected to the inlet of the disinfection tank 11 through a tenth drainage pipe.

[0018] Firefighting wastewater enters the bar screen equalization tank 1, where large particles are intercepted by the screen, and silt is settled. The effluent from the bar screen equalization tank flows through the first inlet pipe into the flocculation sedimentation tank 2, where over 90% of suspended solids are removed, and some COD and phosphorus are adsorbed, reducing the load on subsequent treatment processes. Adding coagulant (polyaluminum chloride PAC) and coagulant aid (polyacrylamide PAM) to the flocculation sedimentation tank 2 accelerates the flocculation and sedimentation of suspended solids. Adding lime slurry to the flocculation sedimentation tank 2 adjusts the pH of the wastewater to 7.5–8.5, creating conditions for subsequent fluoride and phosphorus removal and improving coagulation efficiency. The effluent from the flocculation sedimentation tank flows through the second inlet pipe into the intermediate equalization tank 3, ensuring uniform quality and flow, buffering fluctuations in COD, phosphorus, and fluoride concentrations, and ensuring stable operation in the subsequent core treatment stages. The effluent from the intermediate equalization tank is fed into the catalytic wet oxidation reactor 4 via the third inlet pipe. Under high temperature (180–220℃) and high pressure (6–8 MPa), a catalyst (such as CuO / Al2O3) promotes the reaction of organic matter with oxygen, oxidizing large organic molecules into easily biodegradable small organic molecules, thus improving the efficiency of subsequent biological treatment. The COD removal rate is 60–70% (effluent COD reduced to 5400–19200 mg / L), and some fluoride and phosphorus are removed by oxidation or adsorption (effluent fluoride reduced to 15–150 mg / L, phosphorus reduced to 20–250 mg / L). The effluent from the catalytic wet oxidation reactor is fed into the anaerobic reactor 5 via the fourth inlet pipe. Under anaerobic conditions, large organic molecules are decomposed into methane, carbon dioxide, etc., degrading COD. The effluent from the anaerobic reactor is fed into the aerobic-anoxic reactor 6 via the fifth inlet pipe for further COD degradation and removal of some phosphorus. COD removal rate is 80-90% (effluent COD reduced to 100-1150 mg / L), and biological phosphorus removal rate is 50-60% (effluent phosphorus reduced to 10-100 mg / L). The effluent from the aerobic-anoxic reactor is introduced into the defluoridation and phosphorus removal sedimentation tank 7 via the sixth inlet pipe. Chemical precipitation is used, with lime slurry (Ca(OH)2) added to the wastewater to remove Ca... 2+ respectively with F - and PO4 3-The process generates insoluble CaF2 and Ca3(PO4)2 precipitates, simultaneously removing fluoride and phosphorus. During treatment, controlling the pH value between 8.5 and 9.5 improves sedimentation efficiency, and adding a coagulant aid (polyacrylamide, PAM) accelerates sedimentation separation. Fluoride removal rate ≥95% (effluent fluoride reduced to below 7.5 mg / L), phosphorus removal rate ≥99% (effluent phosphorus reduced to below 2.5 mg / L). The effluent from the fluoride and phosphorus removal sedimentation tank is introduced into the ozone oxidation reactor 8 via the seventh inlet pipe, where ozone oxidation decomposes residual recalcitrant COD. The effluent from the ozone oxidation reactor is introduced into the adsorption tower 9 via the eighth inlet pipe, adsorbing small molecule organic matter and trace pollutants, while further removing fluoride and phosphorus residues. The effluent from the adsorption tower is introduced into the filter tank 10 via the ninth inlet pipe, further removing suspended solids from the wastewater to ensure clear effluent. The effluent from the filtration tank is fed into the disinfection tank 11 through the tenth drainage pipe. Sodium hypochlorite is added to the disinfection tank 11 to ensure that the effluent meets the discharge standards and protects ecological safety.

[0019] To achieve sludge treatment, the system also includes a sludge thickening tank 12 and a filter press 13; the sludge outlet of the flocculation sedimentation tank 2 is connected to the sludge inlet of the sludge thickening tank 12 via a first sludge pipe; the sludge outlet of the anaerobic reactor 5 is connected to the sludge inlet of the sludge thickening tank 12 via a second sludge pipe; the sludge outlet of the aerobic-anoxic reactor 6 is connected to the sludge inlet of the sludge thickening tank 12 via a third sludge pipe; the sludge outlet of the fluoride and phosphorus removal reaction sedimentation tank 7 is connected to the sludge inlet of the sludge thickening tank 12 via a fourth sludge pipe; the sludge outlet of the filter tank 10 is connected to the sludge inlet of the sludge thickening tank 12 via a fifth sludge pipe; and the sludge outlet of the sludge thickening tank 12 is connected to the sludge inlet of the filter press 13 via a sixth sludge pipe.

[0020] The sludge generated from flocculation sedimentation tank 2, anaerobic reactor 5, aerobic-anoxic reactor 6, fluoride and phosphorus removal reaction sedimentation tank 7, and filter tank 10 is further concentrated in sludge thickening tank 12. The concentrated sludge is dewatered by filter press 13, and the dry sludge discharged from filter press 13 is transported to the hazardous waste center for treatment.

[0021] Preferably, the flocculation sedimentation tank 2 is an inclined plate flocculation sedimentation tank.

[0022] Preferably, the anaerobic reactor 5 is a UASB anaerobic reactor. The UASB anaerobic reactor includes an influent and distribution system, a reactor body, and a three-phase separator, and is existing technology.

[0023] Preferably, the adsorption tower 9 is a biochar adsorption tower.

[0024] Preferably, the filter tank 10 is a sand filter. The sand filter 10 further removes suspended solids from the wastewater, ensuring clear effluent. Compared to ultrafiltration or reverse osmosis processes, sand filters meet effluent quality requirements while also offering better economic benefits.

[0025] Preferably, the sludge thickening tank 12 is a gravity thickening tank. After treatment in the gravity thickening tank, the sludge moisture content is reduced from 99.2% to 97%.

[0026] Preferably, the filter press 13 is a plate and frame filter press. The sludge discharged from the sludge thickening tank 12 is pumped to the plate and frame filter press, and the sludge is discharged as dry sludge after the moisture content is reduced to 60%.

[0027] The specific embodiments described are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent changes made to the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A treatment system for fire-fighting wastewater from a lithium iron phosphate battery energy storage power station, characterized in that, The system includes, in sequence, a grid equalization tank (1), a flocculation sedimentation tank (2), an intermediate equalization tank (3), a catalytic wet oxidation reactor (4), an anaerobic reactor (5), an aerobic-anoxic reactor (6), a fluoride and phosphorus removal reaction sedimentation tank (7), an ozone oxidation reactor (8), an adsorption tower (9), a filter tank (10), and a disinfection tank (11). The outlet of the grid equalization tank (1) is connected to the inlet of the flocculation sedimentation tank (2) through a first drainage pipe. The outlet of the flocculation sedimentation tank (2) is connected to the inlet of the intermediate equalization tank (3) through a second drainage pipe. The outlet of the intermediate equalization tank (3) is connected to the inlet of the catalytic wet oxidation reactor (4) through a third drainage pipe. The outlet of the catalytic wet oxidation reactor (4) is connected to the inlet of the anaerobic reactor (5) through a fourth drainage pipe. The outlet of the anaerobic reactor (5) is connected to the inlet of the aerobic-anoxic reactor (6) through a fifth drainage pipe. The outlet of the aerobic-anoxic reactor (6) is connected to the inlet of the defluorination and phosphorus removal reaction sedimentation tank (7) through the sixth drainage pipe. The outlet of the defluorination and phosphorus removal reaction sedimentation tank (7) is connected to the inlet of the ozone oxidation reactor (8) through the seventh drainage pipe. The outlet of the ozone oxidation reactor (8) is connected to the inlet of the adsorption tower (9) through the eighth drainage pipe. The outlet of the adsorption tower (9) is connected to the inlet of the filter tank (10) through the ninth drainage pipe. The outlet of the filter tank (10) is connected to the inlet of the disinfection tank (11) through the tenth drainage pipe.

2. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 1, characterized in that, It also includes a sludge thickening tank (12) and a filter press (13). The sludge outlet of the flocculation sedimentation tank (2) is connected to the sludge inlet of the sludge thickening tank (12) through a first sludge pipe; the sludge outlet of the anaerobic reactor (5) is connected to the sludge inlet of the sludge thickening tank (12) through a second sludge pipe; the sludge outlet of the aerobic-anoxic reactor (6) is connected to the sludge inlet of the sludge thickening tank (12) through a third sludge pipe; the sludge outlet of the defluorination and phosphorus removal reaction sedimentation tank (7) is connected to the sludge inlet of the sludge thickening tank (12) through a fourth sludge pipe; the sludge outlet of the filter tank (10) is connected to the sludge inlet of the sludge thickening tank (12) through a fifth sludge pipe; and the sludge outlet of the sludge thickening tank (12) is connected to the sludge inlet of the filter press (13) through a sixth sludge pipe.

3. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 1, characterized in that, The flocculation sedimentation tank (2) is an inclined plate flocculation sedimentation tank.

4. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 1, characterized in that, The anaerobic reactor (5) is a UASB anaerobic reactor.

5. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 1, characterized in that, The adsorption tower (9) is a biochar adsorption tower.

6. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 1, characterized in that, The filter pool (10) is a sand filter pool.

7. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 2, characterized in that, The sludge thickening tank (12) is a gravity thickening tank.

8. The wastewater treatment system for fire fighting in a lithium iron phosphate battery energy storage power station as described in claim 2, characterized in that, The filter press (13) is a plate and frame filter press.

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