Energy-saving and efficient fly ash water washing dechlorination system and method

Abstract

The application relates to the field of fly ash water washing dechlorination technology, and discloses an energy-saving and efficient fly ash water washing dechlorination system and method, which comprises a fly ash pulping unit for pre-solubilizing the weighed original fly ash, the fly ash pulping unit comprising a precise pre-solubilization control device and an initial slurry buffer pool; a multistage water washing unit for multistage water washing of the pre-solubilized original fly ash initial slurry, the multistage water washing unit being composed of multiple top-driven stirring water washing devices; a multistage vortex separation unit for multistage three-phase separation of the water-washed initial slurry; and the multistage vortex separation unit being composed of multiple integrated vortex three-phase separation devices. Through the organic combination of the fly ash pulping, multistage water washing, multistage vortex separation, mechanical solid-liquid separation, heavy substance removal, evaporation crystallization and waste gas and waste water treatment units, the backflow mechanism of the fly ash water washing is optimized, the water consumption is greatly reduced, the energy is saved and the waste water is zero discharged.

Description

Technical Field

[0001] This invention relates to the field of fly ash water washing and dechlorination technology, specifically to an energy-saving and efficient system and method for fly ash water washing and dechlorination. Background Technology

[0002] Fly ash washing technology is a method for treating fly ash generated during waste incineration. Fly ash contains various harmful substances such as heavy metals, benzene compounds, and dioxins, and is classified as hazardous waste with the hazardous waste code HW18. Among traditional hazardous waste treatment methods, co-processing in cement kilns is a relatively thorough and effective approach. However, due to the high chlorine content in fly ash, it is difficult to directly feed it into the kiln simply by mixing it with other materials. The "Technical Specification for Pollution Control of Fly Ash from Municipal Solid Waste Incineration (Trial)" (HJ 1134-2020) stipulates that "the soluble chlorine content in the treated fly ash should be controlled. High-temperature processes and water washing processes can be used to remove soluble chlorine. The soluble chlorine content in the treated products (high-temperature treated products, water-washed fly ash, etc.) should not exceed 2%", and preferably not exceed 1%. Therefore, dechlorination pretreatment of fly ash is necessary. Water washing pretreatment is currently a mainstream and effective method for removing chloride ions from fly ash.

[0003] In the prior art, CN117600206A discloses a fly ash resource utilization treatment system and process, including a low-temperature detoxification unit to remove dioxins from incineration fly ash; a water washing unit to perform countercurrent water washing on the detoxified fly ash; a heavy metal stabilization unit to solidify heavy metals in the water washing liquid; a water washing detoxification unit to capture heavy metals in the water washing liquid to generate heavy metal precipitates; a softening unit to soften the detoxified water washing liquid to reduce hardness; a membrane treatment unit to separate monovalent and divalent salts; and a salt production unit to evaporate and crystallize the permeate from the membrane treatment unit to produce salt, and to reuse the condensate in the water washing unit. CN202410219764 discloses a method for the resource utilization of fly ash from municipal solid waste incineration. It adopts a three-stage countercurrent circulation ultrasonic enhanced water washing method. Under stirring conditions, combined with the effect of ultrasonic enhancement, chloride ions can be quickly washed away with reduced water consumption. Although the water washing time only needs to be 5-10 minutes per wash, reducing the washing time, the solid-liquid ratio used in each stage of the three-stage countercurrent circulation ultrasonic enhanced water washing is still 1:3-4. Furthermore, CN212039181 U discloses a circulating gradient fly ash washing system, including a clean water tank and a premixing tank. The premixing tanks are all connected to a first pulping tank, and the clean water tanks are all connected to a second pulping tank. The outlet of the first pulping tank is connected to a first filter press. The first filter press includes multiple filtrate outlets and filter cake outlets, which are respectively connected to corresponding storage devices and subsequent water treatment systems. The filter cake outlet is connected to the second pulping tank, the outlet of the second pulping tank is connected to the second filter press, and the filter cake outlet of the second filter press is connected to a drying system. Through effective coordination between the equipment systems, after repeated washing processes, filtrates of different concentrations after a single wash are retained and circulated for washing to reduce water consumption and obtain washing solutions of different concentrations.

[0004] Therefore, it can be seen that in the pretreatment of fly ash dechlorination by water washing, there are generally problems such as large water consumption (the total ash-to-water ratio in the whole washing process is generally greater than 1:3), high cost of subsequent washing liquid treatment (whether it is direct evaporation crystallization or membrane concentration followed by recrystallization, the energy consumption is high, and the water consumption in the water washing process is directly related to the evaporation rate; the larger the water consumption, the higher the operating cost); the solid matter separated by plate and frame centrifuge after water washing needs to be slurryed again, which wastes energy; and the water washing system has too many devices, complicated operation, and frequent replacement of parts. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an energy-efficient and effective system and method for fly ash water washing and dechlorination, solving the problems of high water consumption, high cost of subsequent washing solution treatment, and energy waste in existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an energy-efficient and high-performance fly ash water washing and dechlorination system, comprising:

[0007] The fly ash pulping unit is used for pre-dissolved and weighed raw fly ash, and includes a precise control pre-dissolution device and a primary pulp buffer tank.

[0008] A multi-stage water washing unit is used to perform multi-stage water washing on the pre-dissolved original fly ash slurry. The multi-stage water washing unit consists of multiple top-driven stirring water washing devices.

[0009] A multi-stage eddy current separation unit is used to perform multi-stage three-phase separation on the initial slurry after water washing; the multi-stage eddy current separation unit is composed of multiple integrated eddy current three-phase separation devices;

[0010] A wastewater treatment unit for wastewater treatment includes a wastewater treatment module and a reclaimed water tank. The wastewater treatment module includes, but is not limited to, a multi-stage physicochemical sedimentation system, an MBR system, and a constructed wastewater combination module.

[0011] Preferably, the precise control pre-dissolving device includes a slurry tank, a top-driven variable frequency agitator, and a level controller. The top of the slurry tank, from left to right, has a fly ash inlet, a water inlet 1, a water inlet 2, a maintenance manhole, and a waste gas outlet. The side of the slurry tank, from top to bottom, has an overflow port and a slurry outlet. The bottom of the slurry tank has a vent port. A flow meter for measuring the influent flow rate is connected to the top of the water inlet 2, and a solenoid valve for controlling the influent flow rate is installed at the top of the flow meter. A second flow meter for measuring the influent flow rate is installed at the top of the water inlet 1, and the second flow meter is connected to the recycled water from the wastewater treatment unit. The water pumps in the pool are connected to control the total amount of water entering the tank. The fly ash inlet input is connected to a weighing system for controlling the amount of fly ash entering the tank. The top-drive variable frequency agitator is installed on the top of the slurry tank. The level controller is installed inside the slurry tank to read the level signal inside the slurry tank. The top of the top-drive variable frequency agitator is equipped with a speed controller, which is electrically connected to the level controller and the top-drive variable frequency agitator. The end of the slurry outlet away from the slurry tank is connected to a primary slurry discharge pipe, and the other end of the primary slurry discharge pipe is connected to the primary slurry buffer tank. The primary slurry buffer tank is equipped with a slurry pump for transporting the prepared primary slurry to the subsequent washing unit.

[0012] Preferably, the top-driven agitator washing device includes a washing tank, a top-driven agitator, and a level controller. The top of the washing tank, from left to right, has a slurry inlet, a water inlet three, a water inlet four, a maintenance manhole two, and a waste gas outlet two. The upper and lower ends of the side of the washing tank have an overflow port two and a slurry outlet two, respectively. The bottom of the washing tank has a venting port two. The tops of the slurry inlet, water inlet three, and water inlet four are respectively equipped with a pipe flow meter three, a pipe flow meter four, and a pipe flow meter five for measuring water volume. One end of the slurry outlet two, away from the washing tank, is connected to a variable frequency booster pump input, for transporting the washing slurry to the subsequent eddy current separation unit. The top-driven agitator is installed on the top of the washing tank, and the level controller two is installed inside the washing tank to read the liquid level signal inside the washing tank.

[0013] Preferably, the integrated eddy current three-phase separation device includes a washing liquid storage tank, a concentrated slurry storage tank, and multiple sets of eddy current separators connected between the two. A discharge pipe is installed at the central axis between the washing liquid storage tank and the concentrated slurry storage tank, and an intermittently opening solenoid valve is provided on the discharge pipe. A waste gas outlet and a maintenance manhole are respectively provided on both sides of the top of the washing liquid storage tank. A washing liquid outlet and a washing liquid discharge pipe connected to the washing liquid outlet are provided in the upper part of the washing liquid storage tank. An ash outlet is provided at the bottom of the washing liquid storage tank, and the ash outlet is connected to the discharge pipe. The bottom of the discharge pipe is connected to the concentrated slurry storage tank. A slurry outlet is provided at the bottom of the concentrated slurry storage tank, and a slurry discharge pipe is connected to the bottom of the slurry outlet. A solenoid valve is installed at the other end of the slurry discharge pipe to control the concentrated slurry to flow by gravity to the subsequent receiving unit.

[0014] Preferably, the eddy separator has a water washing slurry inlet pipe on its side, an upward connecting pipe for clear liquid and air at the top of the eddy separator and the connecting pipe is connected to the washing liquid storage tank, and an inverted conical pipe for downward slurry at the bottom of the eddy separator is connected to the concentrated slurry storage tank. The water washing slurry inlet pipes of multiple eddy separators are all connected to a ring-shaped main inlet pipe. A solenoid valve and a variable frequency slurry pump are sequentially connected to the side end of the ring-shaped main inlet pipe to control the slurry volume from the top-driven stirring and washing device and the eddy current intensity in the eddy separator.

[0015] Preferably, the dechlorination system further includes a mechanical solid-liquid separation unit for mud-water separation, which includes a mechanical separation module and a filtrate buffer tank, wherein the mechanical separation module includes, but is not limited to, a plate and frame filter press and a centrifugal separation device.

[0016] Preferably, the dechlorination system further includes a heavy metal removal unit for removing heavy metals, which includes a reaction module and a heavy metal removal sedimentation tank, wherein the reaction module includes, but is not limited to, a flocculation sedimentation device and an electrolysis device.

[0017] Preferably, the dechlorination system further includes an evaporation crystallization unit for evaporation crystallization, which includes an evaporation crystallization device and a condensate tank, wherein the evaporation crystallization device includes, but is not limited to, an MVR device, a membrane concentration + MVR device, and a membrane desalination + membrane concentration + MVR device.

[0018] Preferably, the dechlorination system further includes a waste gas treatment unit for waste gas treatment, which includes a waste gas treatment module and a waste gas emission module, wherein the waste gas treatment module includes, but is not limited to, a spray tower and an activated carbon adsorption device.

[0019] A method for fly ash dechlorination based on the above-mentioned fly ash water washing dechlorination system includes the following steps:

[0020] S1. Pre-dissolving: A certain amount of raw fly ash is added to the pulping unit, and part of the washing liquid from the secondary eddy separation unit is added to the fly ash pulping unit for stirring. Then, the reclaimed water collected from the wastewater treatment unit is added to the fly ash pulping unit and stirred again to obtain a uniform pre-dissolved slurry. Finally, the pre-dissolved slurry is transported to the subsequent primary washing unit.

[0021] S2, Primary Washing: The pre-dissolved slurry in S1 is transported to the primary washing unit. At the same time, all the remaining washing liquid from the secondary eddy separation unit is added to the primary washing unit. The water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary washing unit to produce primary washing slurry. The primary washing slurry is then transported to the primary eddy separation unit.

[0022] S3, Primary eddy separation: The primary water-washed slurry in S2 is transported to the primary eddy separation unit for separation. Then, the upward clear liquid and air after separation are separated from the downward concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The primary washing liquid after separation flows into the subsequent degravation unit by gravity, and the primary concentrated slurry after separation flows to the subsequent secondary water washing unit by gravity.

[0023] S4, Primary Washing Liquid Treatment: The primary washing liquid from S3 is introduced into the deweighting unit for deweighting treatment. The supernatant after deweighting is sent to the evaporation and crystallization unit for treatment. Finally, the evaporation and crystallization unit converts it into industrial salt products. The condensate produced by the evaporation and crystallization unit is temporarily stored in the condensate pool as supplementary water for the process. The sediment sludge after deweighting is pumped to the wastewater treatment unit for treatment. The waste gas generated during the deweighting process is treated by the waste gas treatment system.

[0024] S5, Secondary washing: The primary concentrated slurry from S3 and the filtrate from the mechanical separation unit are introduced into the secondary washing unit. After stirring and washing, the secondary washed slurry is obtained, and then the secondary washed slurry is transported to the secondary eddy current separation unit.

[0025] S6, Secondary eddy separation: The secondary water-washed slurry in S5 is pumped to the secondary eddy separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the slurry preparation unit and the primary water washing unit. At the same time, the distribution ratio of the secondary washing liquid returning to the slurry preparation unit and the primary water washing unit is adjusted as needed. The separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit.

[0026] S7, Third-stage water washing: The secondary concentrated slurry in S6 and the condensate from the evaporation and crystallization unit are introduced into the third-stage water washing unit as supplementary water. After stirring and washing, the third-stage water-washed slurry is obtained.

[0027] S8. Mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the three-stage water-washed slurry into filtrate and solid residue. The filtrate is used as the influent for the two-stage water-washing unit for recirculation treatment, while the solid residue is dechlorinated fly ash.

[0028] S9. Waste gas treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy separation unit, the de-gravity removal unit, and the wastewater treatment unit through the waste gas collection main pipe. The wastewater generated during the treatment is then connected to the wastewater treatment unit, and the treated waste gas is discharged at high altitude.

[0029] S10. Wastewater treatment: The wastewater treatment unit receives the sedimented sludge from the degravation unit and the wastewater from the exhaust gas treatment unit, and connects them to the treatment unit together. The treated effluent is used as recycled water for the pulping unit, while the dewatered sludge is left for subsequent treatment.

[0030] Working Principle: A certain amount of raw fly ash is weighed by a weighing system and fed into the slurry tank through the fly ash inlet. Part of the washing liquid from the secondary eddy current separation unit is introduced into the slurry tank through the second water inlet. The mass ratio of the introduced raw fly ash to the washing liquid is controlled at 0.5–1.5 by a pipeline flow meter and a solenoid valve. The top-drive variable frequency agitator is activated to mix the raw fly ash and washing liquid. Simultaneously, treated wastewater from the wastewater treatment unit is continuously injected into the slurry tank. The mass ratio of the raw fly ash to the treated water is controlled at 1.0–2.0 by a pipeline flow meter and a water pump in the reclaimed water tank. This is achieved through linkage control with the first water inlet... The feed rates of water inlet 2 and fly ash inlet 2 are controlled to maintain the mass ratio of total water to raw fly ash at 1.5–2.5. The liquid level controller 1 reads the liquid level change signal in the slurry tank and transmits the signal to the speed controller to adjust the stirring intensity of the top-driven variable frequency agitator to ensure the slurrying effect. During this process, the exhaust gas in the slurry tank is discharged through exhaust gas outlet 1 and treated in the exhaust gas treatment system. After stirring and slurrying for 10–30 minutes, a pre-dissolved slurry with uniform texture is obtained. The pre-dissolved slurry is introduced into the slurry buffer tank through slurry outlet 1 and slurry discharge pipe, and then transported to the subsequent primary washing unit by the slurry pump in the buffer tank.

[0031] The pre-dissolved slurry is pumped into the washing tank through the slurry inlet. All remaining washing liquid from the secondary vortex separation unit is also introduced into the washing tank through inlet four. The water pump in the condenser of the evaporation and crystallization unit is started, continuously pumping supplementary water into the washing tank through inlet three. The amount of supplementary water is precisely controlled by jointly reading data from pipe flow meters three, four, and five, maintaining the total water-to-slurry mass ratio at 1.0–1.5. During this process, the exhaust gas in the washing tank is discharged through exhaust outlet two and treated in the exhaust gas treatment system. After 45–90 minutes of stirring and washing, primary washed slurry is obtained, with a moisture content of 60–95% and a chlorine content of 5–15%. The primary washed slurry is then transported to the primary vortex separation unit by a variable frequency booster pump through slurry outlet two.

[0032] The primary washing slurry is evenly distributed to several sets of eddy current separators via a ring-shaped main pipe for efficient three-phase separation. The eddy current intensity within the eddy current separators is controlled by adjusting the pressure of a variable frequency booster pump. The separated upward-flowing clear liquid and air are introduced into the washing liquid storage tank via connecting pipes, while the separated downward-flowing concentrated slurry is introduced into the concentrated slurry storage tank via an inverted conical pipe. During this process, the exhaust gas in the washing liquid storage tank is discharged into the exhaust gas treatment system via exhaust outlet three. The separated primary washing liquid flows by gravity into the subsequent degravity removal unit via the washing liquid outlet and washing liquid discharge pipe. The separated primary concentrated slurry with a water content of 70-90% and a chlorine content of 5-15% flows by gravity to the subsequent secondary washing unit via the slurry outlet and slurry discharge pipe, with its flow rate controlled by solenoid valve three. The slurry deposited in the washing liquid storage tank is periodically discharged into the concentrated slurry storage tank via the ash outlet and ash discharge pipe, controlled by solenoid valve two, with a discharge interval of 6-48 hours.

[0033] The primary washing liquid is introduced into the degravation unit for degravation treatment. The supernatant after degravation is then transported to the evaporation and crystallization unit for further processing. Finally, the evaporation and crystallization unit converts the supernatant into industrial salt products. The condensate produced by the evaporation and crystallization unit is temporarily stored in the condensate tank as makeup water for the process. When the makeup water is insufficient, it is supplemented with clean water. The sediment sludge after degravation is pumped to the wastewater treatment unit for treatment, and the waste gas generated during the degravation process is treated by the waste gas treatment system.

[0034] The concentrated slurry from the primary separation unit and the filtrate from the mechanical separation unit are introduced into the washing tank of the secondary washing unit. By controlling the amount of filtrate introduced, the mass ratio of total water to concentrated slurry is controlled at 0.5 to 1.0. After stirring and washing for 45 to 90 minutes, secondary washed slurry is obtained. The secondary washed slurry has a water content of 60 to 95% and a chlorine content of 3 to 10%. It is then transported to the secondary eddy current separation unit by a variable frequency booster pump. The waste gas generated during this process is treated by the waste gas treatment system.

[0035] The secondary washing slurry is added to the secondary eddy current separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the slurry preparation unit and the primary washing unit. The data of the pipeline flow meter 1 in the slurry preparation unit and the pipeline flow meter 3 in the primary washing unit are read. The distribution ratio of the secondary washing liquid returning to the slurry preparation unit and the primary washing unit is adjusted as needed by the control of the solenoid valve 1 in the slurry preparation unit. The separated secondary concentrated slurry has a water content of 70-90% and a chlorine content of 3-10%. The secondary concentrated slurry then flows by gravity to the subsequent tertiary washing unit. The waste gas generated during this process is treated by the waste gas treatment system.

[0036] The condensate from the secondary concentrated mortar and the evaporation crystallization unit is introduced as makeup water into the washing tank of the tertiary washing unit. The mass ratio of total water to concentrated mortar is controlled at 0.5 to 1.0 by controlling the amount of makeup water introduced. After stirring and washing for 45 to 90 minutes, the tertiary washed mortar is obtained. The moisture content of the tertiary washed mortar is 60 to 95%, and the chlorine content is 1 to 5%. The waste gas generated during the process is treated by the waste gas treatment system.

[0037] The mechanical solid-liquid separation unit separates the three-stage water-washed slurry into filtrate and solid residue. The filtrate is entirely used as influent for the secondary water-washing tank for recirculation treatment, while the solid residue can achieve dechlorinated fly ash with a chlorine content of ≤2% and a moisture content of 30% to 50%. This completes the energy-saving and efficient fly ash dechlorination, which can be outsourced for further terminal treatment.

[0038] This invention provides an energy-efficient and highly effective system and method for dechlorinating fly ash through water washing. It offers the following advantages:

[0039] 1. This invention provides an energy-efficient fly ash washing and dechlorination system. By organically combining fly ash pulping, multi-stage washing, multi-stage eddy separation, mechanical solid-liquid separation, weight removal, evaporation crystallization, and waste gas and wastewater treatment units, the system optimizes the fly ash washing reflux mechanism, significantly reducing water consumption while achieving high efficiency and energy saving, and simultaneously achieving "zero discharge" of wastewater.

[0040] 2. This invention utilizes an integrated eddy current three-phase separation device to enable continuous operation of the solid-liquid separation process, significantly improving the efficiency of slurry solid-liquid separation.

[0041] 3. This invention improves the solid-liquid separation device in the fly ash washing process and optimizes the parameters of multi-stage solid-liquid separation, avoiding the process of repeated dewatering and slurrying required in traditional fly ash washing. While ensuring the same washing efficiency, it significantly reduces the water consumption of fly ash washing, significantly reduces the overall size of the equipment, and greatly improves the automation level of the equipment, achieving high efficiency and energy saving. Attached Figure Description

[0042] Figure 1 This is a schematic cross-sectional view of the pre-dissolution device for precise control according to the present invention;

[0043] Figure 2 This is a schematic cross-sectional view of the top-driven stirring and washing device of the present invention;

[0044] Figure 3 This is a front view of the integrated eddy current separation device of the present invention;

[0045] Figure 4 This is a top view of the integrated eddy current separation device of the present invention;

[0046] Figure 5 This is a flowchart of the fly ash water washing dechlorination method of the present invention.

[0047] Among them, A1 is the slurry tank; A2 is the top-driven variable frequency agitator; A3 is the level controller; A4 is the fly ash inlet; A5 is the water inlet; A6 is the water inlet; A7 is the maintenance manhole; A8 is the exhaust outlet; A9 is the overflow port; A10 is the slurry outlet; A11 is the vent port; A12 is the pipeline flow meter; A13 is the solenoid valve; A14 is the pipeline flow meter; A15 is the weighing system; A16 is the speed controller; A17 is the initial slurry discharge pipe; A18 is the initial slurry buffer tank; A19 is the slurry pump; B1 is the washing tank; B2 is the top-driven agitator; B3 is the level controller; B4 is the slurry inlet; B5 is the water inlet; B6 is the water inlet; B7 is the maintenance manhole; B8 is the exhaust outlet; B9 is the overflow port.

[0048] B10, Mortar Discharge Outlet 2; B11, Exhaust Interface 2; B12, Pipeline Flow Meter 3; B13, Pipeline Flow Meter 4; B14, Pipeline Flow Meter 5; B15, Mortar Discharge Pipe; B16, Variable Frequency Booster Pump; C1, Washing Liquid Storage Tank; C2, Concentrated Mortar Storage Tank; C3, Vortex Separator; C4, Ash Discharge Pipe; C5, Exhaust Gas Discharge Outlet 3;

[0049] C6, Inspection Manhole 3; C7, Washing Liquid Outlet; C8, Washing Liquid Discharge Pipe; C9, Ash Outlet; C10, Solenoid Valve 2; C11, Mortar Outlet; C12, Mortar Discharge Pipe; C13, Solenoid Valve 3; C3-1, Water Washing Mortar Inlet Pipe; C3-2, Connecting Conduit; C3-3, Inverted Conical Pipe; C3-4, Circular Inlet Main Pipe; C3-5, Solenoid Valve 4; C3-6, Variable Frequency Slurry Pump. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example:

[0052] Please see the appendix Figure 1 - Appendix Figure 5 This invention provides an energy-efficient fly ash water washing and dechlorination system, comprising:

[0053] The fly ash pulping unit is used for pre-dissolved and weighed raw fly ash, and includes a precise control pre-dissolution device and a primary pulp buffer tank.

[0054] A multi-stage water washing unit is used to perform multi-stage water washing on the pre-dissolved original fly ash slurry. The multi-stage water washing unit consists of multiple top-driven stirring water washing devices.

[0055] A multi-stage eddy current separation unit is used to perform multi-stage three-phase separation on the initial slurry after water washing; the multi-stage eddy current separation unit is composed of multiple integrated eddy current three-phase separation devices;

[0056] The wastewater treatment unit, used for wastewater treatment, includes a wastewater treatment module and a reclaimed water tank. The wastewater treatment module includes, but is not limited to, a multi-stage physicochemical sedimentation system, an MBR system, and a constructed wastewater combination module. The wastewater treatment unit receives settled sludge from the heavy sludge removal unit and wastewater from the exhaust gas treatment unit, and treats them together. The treated effluent is used as reclaimed water in the pulping unit, while the dewatered sludge is properly disposed of by an external contractor.

[0057] The fly ash washing dechlorination system also includes a mechanical solid-liquid separation unit for mud-water separation. It includes a mechanical separation module and a filtrate buffer tank. The mechanical separation module includes, but is not limited to, a plate and frame filter press and a centrifugal separation device. The mechanical solid-liquid separation unit separates the tertiary washing slurry into filtrate and solid residue. All filtrate is used as influent for secondary washing tank and is recycled. The solid residue can achieve dechlorinated fly ash with a chlorine content of ≤2% and a moisture content of 30% to 50%. This completes the energy-saving and efficient fly ash dechlorination, which can be outsourced for further terminal treatment.

[0058] The fly ash water washing dechlorination system also includes a heavy metal removal unit, which includes a reaction module and a heavy metal removal sedimentation tank. The reaction module includes, but is not limited to, a flocculation sedimentation device and an electrolysis device. The fly ash water washing dechlorination system also includes an evaporation crystallization unit, which includes an evaporation crystallization device and a condensate tank. The evaporation crystallization device includes, but is not limited to, an MVR device, a membrane concentration + MVR device, and a membrane desalination + membrane concentration + MVR device. The primary washing liquid obtained in the primary eddy current separation unit is introduced into the heavy metal removal unit for heavy metal removal. The supernatant after heavy metal removal is sent to the evaporation crystallization unit for further processing. Finally, the evaporation crystallization unit converts the supernatant into industrial salt products. The condensate produced by the evaporation crystallization unit is temporarily stored in the condensate tank as makeup water for the process. When the makeup water is insufficient, it is supplemented by clean water (including but not limited to tap water, clean surface water, and clean groundwater). The settled sludge after heavy metal removal is pumped to the wastewater treatment unit for treatment. The waste gas generated during the heavy metal removal process is treated by the waste gas treatment system.

[0059] The fly ash water washing dechlorination system also includes an exhaust gas treatment unit for exhaust gas treatment. This unit includes an exhaust gas treatment module and an exhaust gas emission module. The exhaust gas treatment module includes, but is not limited to, a spray tower and an activated carbon adsorption device. The exhaust gas treatment unit collects exhaust gas from the fly ash pulping unit, the multi-stage water washing unit, the multi-stage eddy separation unit, the degravation unit, and the wastewater treatment unit through an exhaust gas collection main pipe. The wastewater generated during the treatment is then connected to the wastewater treatment unit. The treated exhaust gas is then discharged at high altitude.

[0060] The precise control pre-dissolving device includes a slurry tank A1, a top-driven variable frequency agitator A2, and a level controller A3. From left to right, the top of slurry tank A1 has a fly ash inlet A4, a water inlet A5, a second water inlet A6, a maintenance manhole A7, and a waste gas outlet A8. From top to bottom, the side of slurry tank A1 has an overflow port A9 and a slurry outlet A10. The bottom of slurry tank A1 has a vent port A11. A flow meter A12, which measures the influent flow, is connected to the top of water inlet A6. A solenoid valve A13, which works in conjunction with the flow meter A12 to control the influent flow, is installed at the top of water inlet A12. A flow meter A14, which measures the influent flow, is installed at the top of water inlet A5. Flow meter A14 is connected to the wastewater treatment unit's recycled water tank. A water pump is connected to control the total amount of water entering the tank. The fly ash inlet A4 is connected to a metering scale system A15 for controlling the amount of fly ash entering the tank. A top-drive variable frequency agitator A2 is installed on the top of the slurry tank A1. A level controller A3 is installed inside the slurry tank A1 to read the level signal inside the slurry tank A1. A speed controller A16 is installed on the top of the top-drive variable frequency agitator A2, and the speed controller A16 is electrically connected to the level controller A3 and the top-drive variable frequency agitator A2. The end of the slurry outlet A10 away from the slurry tank A1 is connected to the initial slurry discharge pipe A17, and the other end of the initial slurry discharge pipe A17 is connected to the initial slurry buffer tank A18. The initial slurry buffer tank A18 is equipped with a slurry pump A19 for transporting the prepared initial slurry to the subsequent washing unit.

[0061] Specifically, a certain amount of raw fly ash is weighed by the weighing system A15 and fed into the slurry tank A1 through the fly ash inlet A4. Simultaneously, a portion of the washing liquid from the secondary eddy current separation unit is introduced into the slurry tank A1 through the water inlet A6. The mass ratio of the introduced raw fly ash to the washing liquid is controlled at 0.5–1.5 by the flow meter A12 and the solenoid valve A13. The top-drive variable frequency agitator A2 is started to mix the raw fly ash and the washing liquid. At the same time, treated wastewater from the wastewater treatment unit is continuously injected into the slurry tank A1. The mass ratio of the raw fly ash to the treated water is controlled at 1.0–2.0 by the flow meter A14 and the water pump in the reclaimed water tank. This process is linked to the water inlet A5… The material feed rates at the water inlet A6 and fly ash inlet A4 are controlled to maintain the total water-to-fly ash mass ratio at 1.5–2.5. The liquid level change signal in the slurry tank is read by the level controller A3 and transmitted to the speed controller A16 to adjust the stirring intensity of the top-driven variable frequency agitator A2, ensuring the slurrying effect. During this process, the exhaust gas in the slurry tank A1 is discharged through the exhaust outlet A8 into the exhaust gas treatment system. After 10–30 minutes of stirring and slurrying, a uniform pre-dissolved slurry is obtained. The pre-dissolved slurry is introduced into the slurry buffer tank A18 through the slurry outlet A10 and the slurry discharge pipe A17, and then pumped by the slurry pump A19 to the subsequent primary washing unit.

[0062] The top-driven agitator washing device includes a washing tank B1, a top-driven agitator B2, and a level controller B3. From left to right, the top of the washing tank B1 has a slurry inlet B4, a water inlet B5, a water inlet B6, a maintenance manhole B7, and a waste gas outlet B8. The sides of the washing tank B1 have an overflow port B9 and a slurry outlet B10 at the top and bottom, respectively. The bottom of the washing tank B1 has a vent port B11. At the top of B6 are pipe flow meters three (B12), four (B13), and five (B14) for measuring water volume. The end of mortar outlet two (B10) away from the washing tank B1 is connected to B15. The other end of B15 is connected to the input of the variable frequency booster pump B16, which is used to transport the washing mortar to the subsequent eddy current separation unit. The top drive agitator B2 is installed on the top of the washing tank B1. The level controller two (B3) is installed inside the washing tank B1 to read the level signal inside the washing tank B1.

[0063] Specifically, the pre-dissolved slurry produced in the precise control pre-dissolving device is pumped into the washing tank B1 via slurry inlet B4. All remaining washing liquid from the secondary vortex separation unit is also introduced into the washing tank B1 via water inlet four B6. The water pump in the condenser of the evaporation and crystallization unit is started, continuously pumping makeup water into the washing tank B1 via water inlet three B5. By jointly reading the data from pipeline flow meters three B12 and three B13, and pipeline flow meter five B14, and coordinating with corresponding control valves, the amount of makeup water is precisely controlled, thus controlling the total... The mass ratio of incoming water to initial slurry is controlled at 1.0 to 1.5. During this process, the exhaust gas in the washing tank B1 is discharged through exhaust gas outlet B8 and enters the exhaust gas treatment system for treatment. After stirring and washing for 45 to 90 minutes, the first-stage washed slurry is obtained. After passing through slurry outlets B10 and B15, it is transported to the first-stage eddy separation unit by the variable frequency booster pump B16. During the process, the liquid level in the tank is monitored in real time through the internal liquid level controller B3. When a high liquid level is detected, an alarm is triggered to avoid frequent overflow.

[0064] During the secondary washing process, the concentrated slurry from the primary unit and the filtrate from the mechanical separation unit are introduced into the washing tank of the secondary washing unit. The total water to concentrated slurry mass ratio is controlled at 0.5 to 1.0 by controlling the amount of filtrate introduced. After stirring and washing for 45 to 90 minutes, the secondary washed slurry is obtained and is transported to the secondary eddy current separation unit by the variable frequency booster pump B16 in the secondary washing unit. The waste gas generated during this process is treated by the waste gas treatment system.

[0065] During the three-stage water washing process, the secondary concentrated slurry obtained in the secondary eddy separation unit and the condensate in the evaporation and crystallization unit are introduced as supplementary water into the washing tank of the tertiary water washing unit. The mass ratio of total incoming water to secondary concentrated slurry is controlled at 0.5 to 1.0 by controlling the amount of supplementary water introduced. After stirring and washing for 45 to 90 minutes, the tertiary water-washed slurry is obtained. The waste gas generated during the process is treated by the waste gas treatment system.

[0066] The integrated eddy current three-phase separator includes a washing liquid storage tank C1, a concentrated slurry storage tank C2, and multiple sets of eddy current separators C3 connecting the two. A discharge pipe C4 is installed at the central axis between the washing liquid storage tank C1 and the concentrated slurry storage tank C2, and the discharge pipe C4 is equipped with an intermittently opening solenoid valve C10. The top of the washing liquid storage tank C1 has a waste gas outlet C5 and a maintenance manhole C6 on both sides. The upper part of the washing liquid storage tank C1 has a washing liquid outlet C7 and a washing liquid discharge pipe C8 connected to the outlet C7. The bottom of the washing liquid storage tank C1 has an ash outlet C9, which is connected to the discharge pipe C4. The bottom of the discharge pipe C4 is connected to the concentrated slurry storage tank C2. The bottom of the concentrated slurry storage tank C2 has a slurry outlet C11, and the bottom end of the outlet C11 is connected to a slurry discharge pipe C12. At the other end of pipe C12, a solenoid valve C13 is installed to control the gravity flow of concentrated slurry to the subsequent receiving unit. A water washing slurry inlet pipe C3-1 is provided on the side of eddy separator C3. A connecting conduit C3-2 for upward clear liquid and air is provided at the top of eddy separator C3, and the connecting conduit C3-2 is connected to the washing liquid storage tank C1. An inverted conical pipe C3-3 for downward slurry is provided at the bottom of eddy separator C3, and the inverted conical pipe C3-3 is connected to the concentrated slurry storage tank C2. The water washing slurry inlet pipes C3-1 of multiple eddy separators C3 are all connected to a ring-shaped inlet main pipe C3-4. A solenoid valve C3-5 and a variable frequency slurry pump C3-6 are connected in sequence to the side of the ring-shaped inlet main pipe C3-4, thereby controlling the amount of slurry from the top-driven stirring and washing device and the eddy current intensity in eddy separator C3.

[0067] Specifically, during the first-stage eddy current separation, the first-stage washed slurry obtained from the first-stage washing unit is evenly distributed to several groups of eddy current separators C3 via the annular inlet main pipe C3-4 for efficient three-phase separation. The eddy current intensity within the eddy current separator C3 is controlled by adjusting the pressure of the variable frequency booster pump B16 and the solenoid valve C3-5 in the first-stage washing unit connected to the first-stage eddy current separation. The separated upward clear liquid and air are introduced into the washing liquid storage tank C1 via the connecting conduit C3-2, and the separated downward concentrated slurry is introduced into the concentrated slurry storage tank C2 via the inverted conical pipe C3-3. During this process, the exhaust gas in the washing liquid storage tank C1 is discharged into the exhaust gas treatment system through exhaust gas outlet C5; the separated primary washing liquid flows by gravity into the subsequent de-gravity unit through washing liquid outlet C7 and washing liquid discharge pipe C8; the separated primary concentrated slurry flows by gravity to the subsequent secondary water washing unit through slurry outlet C11 and slurry discharge pipe C12, and its flow rate is controlled by solenoid valve C13; the slurry deposited in the washing liquid storage tank C1 is periodically discharged into the concentrated slurry storage tank C2 through ash outlet C9 and ash discharge pipe C4, controlled by solenoid valve C10, with a discharge interval of 6-48 hours.

[0068] During the secondary eddy separation process, the secondary washing slurry produced in the secondary washing unit is pumped into the eddy separator C3 in the secondary eddy separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the slurry preparation unit and the primary washing unit. The data of the pipeline flow meter A12 in the slurry preparation unit and the pipeline flow meter B12 in the primary washing unit are read. The distribution ratio of the secondary washing liquid returning to the slurry preparation unit and the primary washing unit is adjusted as needed by controlling the solenoid valve A13 in the slurry preparation unit. The waste gas generated during this process is treated by the waste gas treatment system. The separated secondary concentrated slurry flows into the subsequent tertiary washing unit by gravity.

[0069] An energy-efficient and effective fly ash dechlorination method by water washing includes the following steps:

[0070] S1. Pre-dissolving: A certain amount of raw fly ash is added to the pulping unit, and part of the washing liquid from the secondary eddy separation unit is added to the fly ash pulping unit for stirring. Then, the reclaimed water collected from the wastewater treatment unit is added to the fly ash pulping unit and stirred again to obtain a uniform pre-dissolved slurry. Finally, the pre-dissolved slurry is transported to the subsequent primary washing unit.

[0071] S2, Primary Washing: The pre-dissolved slurry in S1 is transported to the primary washing unit. At the same time, all the remaining washing liquid from the secondary eddy separation unit is added to the primary washing unit. The water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary washing unit to produce primary washing slurry. The primary washing slurry is then transported to the primary eddy separation unit.

[0072] S3, Primary eddy separation: The primary water-washed slurry in S2 is transported to the primary eddy separation unit for separation. Then, the upward clear liquid and air after separation are separated from the downward concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The primary washing liquid after separation flows into the subsequent degravation unit by gravity, and the primary concentrated slurry after separation flows to the subsequent secondary water washing unit by gravity.

[0073] S4, Primary Washing Liquid Treatment: The primary washing liquid from S3 is introduced into the deweighting unit for deweighting treatment. The supernatant after deweighting is sent to the evaporation and crystallization unit for treatment. Finally, the evaporation and crystallization unit converts it into industrial salt products. The condensate produced by the evaporation and crystallization unit is temporarily stored in the condensate pool as supplementary water for the process. The sediment sludge after deweighting is pumped to the wastewater treatment unit for treatment. The waste gas generated during the deweighting process is treated by the waste gas treatment system.

[0074] S5, Secondary washing: The primary concentrated slurry from S3 and the filtrate from the mechanical separation unit are introduced into the secondary washing unit. After stirring and washing, the secondary washed slurry is obtained, and then the secondary washed slurry is transported to the secondary eddy current separation unit.

[0075] S6, Secondary eddy separation: The secondary water-washed slurry in S5 is pumped to the secondary eddy separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the slurry preparation unit and the primary water washing unit. At the same time, the distribution ratio of the secondary washing liquid returning to the slurry preparation unit and the primary water washing unit is adjusted as needed. The separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit.

[0076] S7, Third-stage water washing: The secondary concentrated slurry in S6 and the condensate from the evaporation and crystallization unit are introduced into the third-stage water washing unit as supplementary water. After stirring and washing, the third-stage water-washed slurry is obtained.

[0077] S8. Mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the three-stage water-washed slurry into filtrate and solid residue. The filtrate is used as the influent for the two-stage water-washing unit for recirculation treatment, while the solid residue is dechlorinated fly ash.

[0078] S9. Waste gas treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy separation unit, the de-gravity removal unit, and the wastewater treatment unit through the waste gas collection main pipe. The wastewater generated during the treatment is then connected to the wastewater treatment unit, and the treated waste gas is discharged at high altitude.

[0079] S10. Wastewater treatment: The wastewater treatment unit receives the sedimented sludge from the degravation unit and the wastewater from the exhaust gas treatment unit, and connects them to the treatment unit together. The treated effluent is used as recycled water for the pulping unit, while the dewatered sludge is left for subsequent treatment.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An energy-efficient and high-performance fly ash water washing and dechlorination system, characterized in that, include: The fly ash pulping unit is used for pre-dissolved and weighed raw fly ash, and includes a precise control pre-dissolution device and a primary pulp buffer tank. A multi-stage water washing unit is used to perform multi-stage water washing on the pre-dissolved original fly ash slurry. The multi-stage water washing unit consists of multiple top-driven stirring water washing devices. A multi-stage eddy current separation unit is used for multi-stage three-phase separation of the initial slurry after water washing; This multi-stage eddy current separation unit consists of multiple integrated eddy current three-phase separation devices; Wastewater treatment unit for wastewater treatment, comprising a wastewater treatment module and a reclaimed water tank, wherein the wastewater treatment module includes, but is not limited to, a multi-stage physicochemical sedimentation system, an MBR system, and a constructed wastewater combination module; The integrated eddy current three-phase separator includes a washing liquid storage tank (C1), a concentrated slurry storage tank (C2), and multiple sets of eddy current separators (C3) connected between the two. A discharge pipe (C4) is installed at the central axis between the washing liquid storage tank (C1) and the concentrated slurry storage tank (C2), and an intermittently opening solenoid valve (C10) is installed on the discharge pipe (C4). Exhaust gas outlets (C5) and maintenance manholes (C6) are respectively located on both sides of the top of the washing liquid storage tank (C1). A washing liquid outlet (C7) is located in the upper part of the washing liquid storage tank (C1), and... The washing liquid outlet (C7) is connected to the washing liquid discharge pipe (C8). The washing liquid storage tank (C1) is provided with an ash outlet (C9) at the bottom. The ash outlet (C9) is connected to the ash discharge pipe (C4), and the bottom of the ash discharge pipe (C4) is connected to the concentrated slurry storage tank (C2). The concentrated slurry storage tank (C2) is provided with a slurry outlet (C11) at the bottom. The bottom end of the slurry outlet (C11) is connected to the slurry discharge pipe (C12), and the other end of the slurry discharge pipe (C12) is equipped with a solenoid valve three (C13) for controlling the concentrated slurry to flow by gravity to the subsequent receiving unit. The vortex separator (C3) has a water washing slurry inlet pipe (C3-1) on its side. The top of the vortex separator (C3) has an upward connecting pipe (C3-2) for clear liquid and air, and the connecting pipe (C3-2) is connected to the washing liquid storage tank (C1). The bottom of the vortex separator (C3) has an inverted conical pipe (C3-3) for downward slurry, and the inverted conical pipe (C3-3) is connected to the concentrated slurry storage tank (C2). The water washing slurry inlet pipes (C3-1) of the multiple vortex separators (C3) are all connected to a ring-shaped main inlet pipe (C3-4). The side end of the ring-shaped main inlet pipe (C3-4) is connected to a solenoid valve four (C3-5) and a variable frequency slurry pump (C3-6) in sequence, thereby controlling the amount of slurry from the top-driven stirring and washing device and the vortex intensity in the vortex separator (C3). The dechlorination system also includes a mechanical solid-liquid separation unit, a weight removal unit, and an evaporation crystallization unit.

2. The energy-efficient fly ash water washing and dechlorination system according to claim 1, characterized in that, The precise control pre-dissolving device includes a slurry tank (A1), a top-driven variable frequency agitator (A2), and a level controller (A3). The top of the slurry tank (A1) has, from left to right, a fly ash inlet (A4), a water inlet (A5), a water inlet (A6), a maintenance manhole (A7), and a waste gas outlet (A8). The side of the slurry tank (A1) has, from top to bottom, an overflow port (A9) and a slurry outlet (A10). The bottom of the slurry tank (A1) has a vent port (A11). The top of the water inlet (A6) is connected to a flow meter (A12) for measuring the influent flow rate, and the top of the flow meter (A12) is equipped with a solenoid valve (A13) that controls the influent flow rate. The top of the water inlet (A5) is equipped with a flow meter (A14) for measuring the influent flow rate, and the flow meter (A14) is connected to the wastewater treatment unit for reuse. A water pump is connected in the water tank to control the total amount of water entering. The input end of the fly ash inlet (A4) is connected to a metering scale system (A15) for controlling the amount of fly ash entering. The top-drive variable frequency agitator (A2) is installed on the top of the slurry tank (A1). The level controller (A3) is installed inside the slurry tank (A1) to read the level signal inside the slurry tank (A1). A speed controller (A16) is installed on the top of the top-drive variable frequency agitator (A2), and the speed controller (A16) is electrically connected to the level controller (A3) and the top-drive variable frequency agitator (A2). The end of the slurry outlet (A10) away from the slurry tank (A1) is connected to the primary slurry discharge pipe (A17), and the other end of the primary slurry discharge pipe (A17) is connected to the primary slurry buffer tank (A18). The primary slurry buffer tank (A18) is equipped with a slurry pump (A19) for transporting the prepared primary slurry to the subsequent washing unit.

3. The energy-efficient fly ash water washing and dechlorination system according to claim 2, characterized in that, The top-driven agitator washing device includes a washing tank (B1), a top-driven agitator (B2), and a level controller (B3). The top of the washing tank (B1) has, from left to right, a mortar inlet (B4), a water inlet (B5), a water inlet (B6), a maintenance manhole (B7), and a waste gas outlet (B8). The sides of the washing tank (B1) have an overflow port (B9) at the top and bottom, and a mortar outlet (B10) at the bottom. The bottom of the washing tank (B1) has a vent port (B11). The mortar inlet (B4), water inlet (B5), and water inlet (B6) are connected to the water level controller (B3). The top of the inlet four (B6) is equipped with pipe flow meters three (B12), four (B13), and five (B14) for measuring water volume. The end of the mortar outlet two (B10) away from the washing tank (B1) is connected to (B15), and the other end of (B15) is connected to the input of the variable frequency booster pump (B16) for conveying the washing mortar to the subsequent eddy current separation unit. The top drive agitator (B2) is installed on the top of the washing tank (B1), and the level controller two (B3) is installed inside the washing tank (B1) for reading the level signal inside the washing tank (B1).

4. The energy-saving and efficient fly ash water washing and dechlorination system according to claim 3, characterized in that, A mechanical solid-liquid separation unit for mud-water separation includes a mechanical separation module and a filtrate buffer tank. The mechanical separation module includes, but is not limited to, a plate and frame filter press and a centrifugal separation device.

5. The energy-efficient fly ash water washing and dechlorination system according to claim 4, characterized in that, The heavy metal removal unit is used to remove heavy metals. It includes a reaction module and a heavy metal removal sedimentation tank. The reaction module includes, but is not limited to, a flocculation sedimentation device and an electrolysis device.

6. The energy-efficient fly ash water washing and dechlorination system according to claim 5, characterized in that, An evaporation crystallization unit is used for evaporation crystallization. It includes an evaporation crystallization device and a condensate tank. The evaporation crystallization device includes, but is not limited to, an MVR device, a membrane concentration + MVR device, and a membrane desalination + membrane concentration + MVR device.

7. The energy-saving and efficient fly ash water washing and dechlorination system according to claim 6, characterized in that, The dechlorination system also includes a waste gas treatment unit for waste gas treatment, which includes a waste gas treatment module and a waste gas emission module. The waste gas treatment module includes, but is not limited to, a spray tower and an activated carbon adsorption device.

8. The fly ash water washing and dechlorination method based on the fly ash water washing and dechlorination system of claim 7, characterized in that, Includes the following steps: S1. Pre-dissolving: A certain amount of raw fly ash is added to the pulping unit, and part of the washing liquid from the secondary eddy separation unit is added to the fly ash pulping unit for stirring. Then, the reclaimed water collected from the wastewater treatment unit is added to the fly ash pulping unit and stirred again to obtain a uniform pre-dissolved slurry. Finally, the pre-dissolved slurry is transported to the subsequent primary washing unit. S2, Primary Washing: The pre-dissolved slurry in S1 is transported to the primary washing unit. At the same time, all the remaining washing liquid from the secondary eddy separation unit is added to the primary washing unit. The water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary washing unit to produce primary washing slurry. The primary washing slurry is then transported to the primary eddy separation unit. S3, Primary eddy separation: The primary water-washed slurry in S2 is transported to the primary eddy separation unit for separation. Then, the upward clear liquid and air after separation are separated from the downward concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The primary washing liquid after separation flows into the subsequent degravation unit by gravity, and the primary concentrated slurry after separation flows to the subsequent secondary water washing unit by gravity. S4, Primary Washing Liquid Treatment: The primary washing liquid from S3 is introduced into the deweighting unit for deweighting treatment. The supernatant after deweighting is sent to the evaporation and crystallization unit for treatment. Finally, the evaporation and crystallization unit converts it into industrial salt products. The condensate produced by the evaporation and crystallization unit is temporarily stored in the condensate pool as supplementary water for the process. The sediment sludge after deweighting is pumped to the wastewater treatment unit for treatment. The waste gas generated during the deweighting process is treated by the waste gas treatment system. S5, Secondary washing: The primary concentrated slurry from S3 and the filtrate from the mechanical separation unit are introduced into the secondary washing unit. After stirring and washing, the secondary washed slurry is obtained, and then the secondary washed slurry is transported to the secondary eddy current separation unit. S6, Secondary eddy separation: The secondary water-washed slurry in S5 is pumped to the secondary eddy separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the slurry preparation unit and the primary water washing unit. At the same time, the distribution ratio of the secondary washing liquid returning to the slurry preparation unit and the primary water washing unit is adjusted as needed. The separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit. S7, Third-stage water washing: The secondary concentrated slurry in S6 and the condensate from the evaporation and crystallization unit are introduced into the third-stage water washing unit as supplementary water. After stirring and washing, the third-stage water-washed slurry is obtained. S8. Mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the three-stage water-washed slurry into filtrate and solid residue. The filtrate is used as the influent for the two-stage water-washing unit for recirculation treatment, while the solid residue is dechlorinated fly ash. S9. Waste gas treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy separation unit, the de-gravity removal unit, and the wastewater treatment unit through the waste gas collection main pipe. The wastewater generated during the treatment is then connected to the wastewater treatment unit, and the treated waste gas is discharged at high altitude. S10. Wastewater treatment: The wastewater treatment unit receives the sedimented sludge from the degravation unit and the wastewater from the exhaust gas treatment unit, and connects them to the treatment unit together. The treated effluent is used as recycled water for the pulping unit, while the dewatered sludge is left for subsequent treatment.

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