CN118875001A - Energy-saving and efficient fly ash water washing and dechlorination system and method - Google Patents

Abstract

The application relates to the technical field of fly ash water washing and dechlorination, and discloses an energy-saving and efficient system and method for fly ash water washing and dechlorination, wherein the system comprises the following steps: the fly ash pulping unit is used for pre-dissolving the weighed raw fly ash and comprises a precise control pre-dissolving device and a primary slurry buffer pool; the multi-stage washing unit is used for carrying out multi-stage washing on the pre-dissolved primary fly ash slurry and consists of a plurality of top driving stirring washing devices; the multistage vortex separation unit is used for carrying out multistage three-phase separation on the primary pulp after water washing; the multistage vortex separation unit is composed of a plurality of integrated vortex three-phase separation devices. Through the organic combination of fly ash pulping, multistage water washing, multistage vortex separation, mechanical solid-liquid separation, heavy removal, evaporative crystallization, waste gas and wastewater treatment units, the reflux mechanism of the fly ash water washing is optimized, the water consumption is greatly reduced, the high efficiency and the energy conservation are realized, and meanwhile, the zero emission of wastewater is realized.

Description

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

Technical Field

The invention relates to the technical field of fly ash water washing and dechlorination, and in particular to an energy-saving and efficient fly ash water washing and dechlorination system and method.

Background Art

Fly ash washing technology is a method for treating fly ash generated during the incineration of waste. Fly ash is classified as hazardous waste because it contains a variety of harmful substances such as heavy metals, benzene, dioxins, etc., and the hazardous waste code is HW18. Among the traditional methods of hazardous waste treatment, cement kiln co-treatment is a more thorough and effective way, but because the chlorine content in fly ash is too high, it is difficult to directly enter the kiln through compatibility. The "Technical Specifications for Pollution Control of Fly Ash from Municipal Waste Incineration (Trial)" (HJ 1134-2020) stipulates that "the soluble chlorine content in the fly ash treatment product should be controlled, and high-temperature processes, water washing processes, etc. can be used to remove soluble chlorine. The soluble chlorine content in the treatment product (high-temperature treatment product, fly ash after water washing, etc.) should not exceed 2%", preferably not more than 1%. Therefore, fly ash needs to be pretreated for dechlorination. Water washing pretreatment is currently a more mainstream method for effectively removing chloride ions from fly ash.

In the prior art, CN117600206A discloses a fly ash resource processing system and process, including a low-temperature detoxification unit to remove dioxin substances from incineration fly ash; a water washing unit to countercurrently wash the detoxified fly ash; a heavy metal stabilization unit to solidify the heavy metals in the washing liquid; a water washing and detoxification unit to capture the heavy metals in the washing liquid to generate heavy metal precipitates; a softening unit to soften the detoxified washing liquid to reduce the hardness; a membrane treatment unit to separate monovalent salts and divalent salts; a salt making unit to evaporate and crystallize the produced water of the membrane treatment unit to make salt, and reuse the condensed water for the water washing unit. CN202410219764 discloses a method for resource utilization of fly ash from the incineration of domestic waste. By adopting 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 eluted with reduced water consumption. Although the washing time is only 5-10 minutes, which reduces the elution time, the solid-liquid ratio used in each stage of the three-stage countercurrent circulation ultrasonic enhanced water washing is still 1:3~4. In addition, CN212039181 U discloses a circulating gradient fly ash water washing system, including a clean water tank and a premixing tank, the premixing tanks are connected to a first pulping tank, the clean water tanks are connected to a second pulping tank, and the liquid 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 liquid storage devices and subsequent water treatment systems, and the filter cake outlet is connected to a second pulping tank, the second pulping tank outlet is connected to a second filter press, and the filter cake outlet of the second filter press is connected to a drying system; through effective coordination between equipment systems, after repeated water washing processes, filtrates of different concentrations after a single water washing are retained and circulated for water washing to reduce water consumption, and water washing solutions of different concentrations are obtained respectively.

It can be seen that in the pretreatment of fly ash dechlorination by washing, there is a general problem of large water consumption (the total ash-to-water ratio of the whole washing process is generally greater than 1:3), and high cost of subsequent washing liquid treatment (whether it is direct evaporation crystallization or membrane concentration followed by additional crystallization, the energy consumption itself is high, and the water used in the washing process is directly related to the evaporation amount. The greater the water consumption, the higher the operating cost); the solid matter separated by plate and frame and centrifugal separation after washing needs to be slurried again, which wastes energy; there are too many equipment in the washing system, complicated operation, and frequent replacement of accessories.

Summary of the invention

In view of the deficiencies of the prior art, the present invention provides an energy-saving and efficient fly ash water washing and dechlorination system and method, which solves the problems of large water consumption, high subsequent washing liquid treatment costs and energy waste in the prior art.

To achieve the above objectives, the present invention is implemented through the following technical solutions: an energy-saving and efficient fly ash water washing and dechlorination system, comprising:

The fly ash pulping unit is used to pre-dissolve the weighed raw fly ash, which 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 raw fly ash slurry. The multi-stage water washing unit is composed of a plurality of top-driven stirring water washing devices;

A multi-stage eddy current separation unit is used to perform multi-stage three-phase separation on the primary pulp after water washing; the multi-stage eddy current separation unit is composed of a plurality of integrated eddy current three-phase separation devices;

The wastewater treatment unit is used for wastewater treatment, which includes a wastewater treatment module and a reuse water pool, wherein the wastewater treatment module includes but is not limited to a multi-stage physical and chemical sedimentation system, an MBR system, and a constructed wastewater combination module.

Preferably, the precise control pre-dissolution device comprises a pulping tank, a top-driven variable frequency agitator and a liquid level controller; the top of the pulping tank is provided with a fly ash inlet, a water inlet 1, a water inlet 2, a maintenance manhole 1 and a waste gas outlet 1 from left to right in sequence; the side of the pulping tank is provided with an overflow interface 1 and a slurry outlet 1 from top to bottom in sequence; the bottom of the pulping tank is provided with an emptying interface 1; the top of the water inlet 2 is connected to a pipeline flow meter 1 for measuring the water inlet amount, and the top of the pipeline flow meter 1 is equipped with an electromagnetic valve 1 for cooperating with it to control the water inlet amount; the top of the water inlet 1 is equipped with a pipeline flow meter 2 for measuring the water inlet amount, and the pipeline flow meter 2 and the recycled water of the wastewater treatment unit The water pump in the pool is connected to control the total amount of water entering, the fly ash inlet input end is connected to a metering scale system for controlling the ash intake amount, the top drive variable frequency agitator is installed on the top of the pulping tank, the liquid level controller 1 is installed inside the pulping tank for reading the liquid level signal in the pulping tank, a speed controller is installed on the top of the top drive variable frequency agitator, and the speed controller is electrically connected to the liquid level controller 1 and the top drive variable frequency agitator respectively, the slurry discharge port 1 is connected to a primary slurry discharge pipe at one end away from the pulping tank, and the other end of the primary slurry discharge pipe is connected to the primary slurry buffer tank, and a slurry pump is provided in the primary slurry buffer tank for transporting the prepared primary slurry to the subsequent water washing unit.

Preferably, the top-driven stirring water washing device comprises a water washing tank, a top-driven agitator and two liquid level controllers; a mortar inlet, a third water inlet, a fourth water inlet, two inspection manholes and two exhaust gas outlets are provided on the top of the water washing tank from left to right in sequence; two overflow interfaces and two mortar outlets are provided at the upper and lower ends of the side of the water washing tank respectively; a drain interface is provided at the bottom of the water washing tank; three, four and five pipeline flow meters for measuring water volume are respectively installed at the top of the mortar inlet, the third water inlet and the fourth water inlet; one end of the mortar outlet two away from the water washing tank is connected to, and the other end is connected to the input end of the variable frequency booster pump for conveying the water-washed slurry to the subsequent eddy current separation unit; the top-driven agitator is installed on the top of the water washing tank; and the two liquid level controllers are installed inside the water washing tank for reading the liquid level signal in the water washing tank.

Preferably, the integrated eddy current three-phase separation device includes a washing liquid storage tank, a concentrated slurry storage tank and a plurality of eddy current separators connected therebetween; an ash discharge pipe is installed at the central axis between the washing liquid storage tank and the concentrated slurry storage tank, and an intermittently opened solenoid valve 2 is provided on the ash discharge pipe; exhaust gas outlet 3 and inspection manhole 3 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 and middle part of the washing liquid storage tank; an ash outlet is provided at the bottom of the washing liquid storage tank, the ash outlet is connected to the ash discharge pipe, and the bottom of the ash discharge pipe is connected to the concentrated slurry storage tank; a slurry outlet is provided at the bottom of the concentrated slurry storage tank, the bottom end of the slurry outlet is connected to the slurry discharge pipe, and the other end of the slurry discharge pipe is provided with an solenoid valve 3 for controlling the self-flow of concentrated slurry to a subsequent receiving unit.

Preferably, a water-washed slurry access pipe is provided on the upper side of the eddy current separator, a connecting conduit for ascending clear liquid and air is provided on the top of the eddy current separator, and the connecting conduit is connected to the washing liquid storage tank, an inverted cone pipe for descending slurry is provided at the bottom of the eddy current separator, and the inverted cone pipe is connected to the concentrated slurry storage tank, and the water-washed slurry access pipes of multiple eddy current separators are all connected to an annular access main pipe, and the side end of the annular access main pipe is sequentially connected to an electromagnetic valve four and a variable frequency slurry pump, so as to control the slurry amount from the top driven stirring and water washing device and the eddy current intensity in the eddy current separator.

Preferably, the dechlorination system further comprises a mechanical solid-liquid separation unit for mud-water separation, which comprises 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 device and a centrifugal separation device.

Preferably, the dechlorination system further comprises a weight removal unit for removing heavy metals, which comprises a reaction module and a weight removal sedimentation tank, wherein the reaction module includes but is not limited to a flocculation sedimentation device and an electroanalysis device.

Preferably, the dechlorination system further comprises an evaporation crystallization unit for evaporation crystallization, which comprises an evaporation crystallization device and a condensation water pool, wherein the evaporation crystallization device includes but is not limited to an MVR device, a membrane concentration + MVR device, a membrane salt separation + membrane concentration + MVR device.

Preferably, the dechlorination system further comprises a waste gas treatment unit for waste gas treatment, which comprises 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.

A fly ash water washing and dechlorination method based on the fly ash water washing and dechlorination system comprises the following steps:

S1, pre-dissolution: adding a certain amount of raw fly ash to the pulping unit, adding part of the washing liquid from the secondary eddy current separation unit to the fly ash pulping unit for stirring, then adding the reclaimed water collected from the wastewater treatment unit to the fly ash pulping unit, stirring again, to obtain a uniform pre-dissolved primary slurry, and finally transporting the pre-dissolved primary slurry to the subsequent primary water washing unit;

S2, primary water washing: the pre-dissolved primary slurry in S1 is transported to the primary water washing unit, and at the same time, all the remaining washing liquid of the secondary eddy current separation unit is added to the primary water washing unit, and the water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary water washing unit to obtain primary water-washed slurry, and then the obtained primary water-washed slurry is transported to the primary eddy current separation unit;

S3, primary eddy current separation: the primary water-washed slurry in S2 is transported to the primary eddy current separation unit for separation, and then the separated ascending clear liquid and air are separated from the separated descending concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The separated primary washing liquid flows by gravity into the subsequent weight removal unit, and the separated primary concentrated slurry flows by gravity to the subsequent secondary water washing unit;

S4, primary washing liquid treatment: the primary washing liquid in S3 is introduced into the de-weighting unit for de-weighting treatment, and the supernatant after de-weighting is transported to the evaporation crystallization unit for treatment, and finally it is resourced into industrial salt products through the evaporation crystallization unit, while the condensed water generated by the evaporation crystallization unit is temporarily stored in the condensed water pool as supplementary water for the process link, and the precipitated sludge after de-weighting is pumped to the wastewater treatment unit for treatment, and the waste gas generated during the de-weighting process is treated by the waste gas treatment system;

S5, secondary water washing: the primary concentrated slurry in S3 and the filtrate from the mechanical separation unit are introduced into the secondary water washing unit, and after stirring and washing, the secondary water-washed slurry is obtained, and then the secondary water-washed slurry is transported to the secondary eddy current separation unit;

S6, secondary eddy current separation: the secondary water-washed slurry in S5 is pumped to the secondary eddy current separation unit for efficient three-phase separation, and the separated secondary washing liquid flows by gravity to the pulping unit and the primary water washing unit, and the distribution ratio of the secondary washing liquid back to the pulping unit and the primary water washing unit is adjusted as needed, and the separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit;

S7, tertiary water washing: the secondary concentrated slurry in S6 and the condensed water of the evaporation crystallization unit are introduced into the tertiary water washing unit as supplementary water, and after stirring and washing, the tertiary water-washed slurry is obtained;

S8, mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the tertiary water-washed slurry into filtrate and solid residue. The filtrate is all refluxed as the influent of the secondary water-washing unit, and the solid residue is dechlorinated fly ash;

S9. Waste gas supporting treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy current separation unit, the weight removal unit, and the waste water treatment unit through the waste gas collection main pipe, and connects the waste water generated by the treatment to the waste water treatment unit, and the treated waste gas is discharged into the air;

S10. Wastewater treatment: The wastewater treatment unit receives the precipitated sludge from the weight removal unit and the wastewater from the waste gas treatment unit, and treats them together. The treated effluent is used as recycled water in the pulping unit, and the dewatered sludge is retained for subsequent treatment.

Working principle: a certain amount of fly ash raw ash is weighed through the metering scale system and put into the pulping tank through the fly ash inlet, part of the washing liquid of the secondary eddy current separation unit is introduced into the pulping tank through the water inlet 2, and the mass ratio of the introduced fly ash raw ash and washing liquid is controlled at 0.5-1.5 through the control of pipeline flow meter 1 and solenoid valve 1, and the top drive variable frequency agitator is started to mix the fly ash raw ash and washing liquid, and at the same time, the treated reclaimed water of the wastewater treatment unit is continuously injected into the pulping tank, and the mass ratio of fly ash raw ash and reclaimed water is controlled at 1.0-2.0 through the control of pipeline flow meter 2 and the water pump in the regeneration water tank; through the linkage control with the water inlet 1, The material intake of the second incoming water inlet and the fly ash inlet is controlled to control the mass ratio of the total incoming water to the fly ash raw ash at 1.5-2.5; the liquid level change signal in the pulping tank is read through the liquid level controller 1, and the signal is transmitted to the speed controller to adjust the stirring intensity of the top drive variable frequency agitator to ensure the pulping effect; in this process, the waste gas in the pulping tank is discharged through the waste gas outlet 1 and enters the waste gas treatment system for treatment; after 10-30 minutes of stirring and pulping, a uniform pre-dissolved primary slurry is obtained, and the pre-dissolved primary slurry is introduced into the primary slurry buffer tank through the slurry outlet 1 and the primary slurry discharge pipe, and the slurry pump inside it transports the pre-dissolved primary slurry to the subsequent first-level water washing unit;

The pre-dissolved primary slurry is pumped into the water washing tank through the slurry inlet, and all the remaining washing liquid of the secondary eddy current separation unit is also introduced into the water washing tank through the incoming water inlet four, and the water pump in the condensation pool of the evaporation crystallization unit is started, and the supplementary water is continuously pumped into the water washing tank through the incoming water inlet three. By jointly reading the data of the pipeline flow meter three, the pipeline flow meter four, and the pipeline flow meter five, the amount of supplementary water is accurately controlled, and the mass ratio of the total incoming water to the primary slurry is controlled at 1.0-1.5; in this process, the waste gas in the water washing tank is discharged through the waste gas outlet two and enters the waste gas treatment system for treatment; after 45-90 minutes of stirring and washing, the first-level water-washed slurry is obtained, and the water content of the first-level water-washed slurry is 60-95%, and the chlorine content is 5-15%. Then, the first-level water-washed slurry is transported to the first-level eddy current separation unit by the variable frequency booster pump after passing through the slurry outlet two;

The primary water-washed slurry is evenly distributed to several groups of eddy current separators through the annular access main pipe for three-phase efficient separation, and the eddy current intensity in the eddy current separator is controlled by adjusting the pressure of the variable frequency booster pump; the separated upward clear liquid and air are introduced into the washing liquid storage tank through the connecting conduit, and the separated downward concentrated slurry is introduced into the concentrated slurry storage tank through the inverted cone pipe; in this process, the waste gas in the washing liquid storage tank is led out through the waste gas outlet three and enters the waste gas treatment system for treatment; the separated primary washing liquid flows into the subsequent weight removal unit through the washing liquid outlet and the washing liquid discharge pipe by gravity; the separated primary concentrated slurry with a moisture content of 70-90% and a chlorine content of 5-15% flows to the subsequent secondary water washing unit through the slurry outlet and the slurry discharge pipe by gravity, and its flow is controlled by the electromagnetic valve three; the slurry deposited in the washing liquid storage tank is discharged to the concentrated slurry storage tank regularly through the ash outlet and the ash discharge pipe controlled by the electromagnetic valve two, and the discharge interval time is 6-48h;

The primary washing liquid is introduced into the de-weighting unit for de-weighting treatment. The supernatant after de-weighting is transported to the evaporation crystallization unit for treatment, and finally it is converted into industrial salt products through the evaporation crystallization unit. The condensed water produced by the evaporation crystallization unit is temporarily stored in the condensed water pool as supplementary water for the process. When the supplementary water is insufficient, it is supplemented by clean water. The precipitated sludge after de-weighting is pumped to the wastewater treatment unit for treatment, and the waste gas produced during the de-weighting process is treated by the waste gas treatment system.

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

The secondary water-washed 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 pulping unit and the primary water washing unit. The data of the pipeline flow meter 1 in the pulping unit and the pipeline flow meter 3 in the primary water washing unit are read, and the distribution ratio of the secondary washing liquid refluxed to the pulping unit and the primary water washing unit is adjusted as needed through the control of the solenoid valve 1 in the pulping unit. The separated secondary concentrated slurry has a water content of 70-90% and a chlorine content of 3-10%. After that, the secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit, and the waste gas generated during the process is treated by the waste gas treatment system;

The condensed water of the secondary concentrated slurry and the evaporation crystallization unit are respectively introduced as supplementary water into the washing tank of the tertiary washing unit, and the mass ratio of the total incoming water to the concentrated slurry is adjusted to be controlled at 0.5-1.0 by controlling the amount of the introduced supplementary water; after 45-90 minutes of stirring and washing, a tertiary washed slurry is obtained, the moisture content of the tertiary washed slurry is 60-95%, the chlorine content is 1-5%, and the waste gas generated during this period is treated by the waste gas treatment system;

The mechanical solid-liquid separation unit separates the tertiary washed slurry into filtrate and solid residue. All the filtrate is refluxed as the inlet water of the secondary washing tank, and the solid residue can achieve dechlorinated fly ash with a chlorine content of ≤2% and a moisture content of 30% to 50%. Energy-saving and efficient fly ash dechlorination is thus completed and can be outsourced for further terminal disposal.

The present invention provides an energy-saving and efficient fly ash water washing and dechlorination system and method. It has the following beneficial effects:

1. The present invention provides an energy-saving and efficient fly ash water washing and dechlorination system, which optimizes the reflux mechanism of fly ash water washing through the organic combination of fly ash pulping, multi-stage water washing, multi-stage eddy current separation, mechanical solid-liquid separation, weight removal, evaporation crystallization and waste gas and wastewater treatment units, and achieves high efficiency and energy saving while greatly reducing water consumption, and at the same time achieves "zero discharge" of wastewater.

2. The present invention uses an integrated eddy current three-phase separation device to achieve continuous operation of the solid-liquid separation process, greatly improving the efficiency of slurry solid-liquid separation.

3. The present invention improves the solid-liquid separation device in the fly ash washing process and optimizes the parameters of the multi-stage solid-liquid separation, avoiding the repeated dehydration and slurrying processes required for traditional fly ash washing. While ensuring the same washing efficiency, the water consumption of fly ash washing is greatly reduced, the total volume of the equipment is significantly reduced, and the degree of automation of the equipment is greatly improved, which is highly efficient and energy-saving.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic cross-sectional view of the structure of a precise control pre-dissolution device of the present invention;

FIG2 is a schematic cross-sectional view of the structure of the top driven stirring water washing device of the present invention;

FIG3 is a front view of the structure of the integrated eddy current separator of the present invention;

FIG4 is a top view of the structure of the integrated eddy current separator of the present invention;

FIG5 is a flow chart of the fly ash water washing and dechlorination method of the present invention.

Among them, A1, pulping tank; A2, top drive variable frequency agitator; A3, liquid level controller 1; A4, fly ash inlet; A5, water inlet 1; A6, water inlet 2; A7, maintenance manhole 1; A8, exhaust gas outlet 1; A9, overflow interface 1; A10, slurry outlet 1; A11, emptying interface 1; A12, pipeline flow meter 1; A13, solenoid valve 1; A14, pipeline flow meter 2; A15, metering scale system; A16, speed controller; A17, primary slurry discharge pipe; A18, primary slurry buffer tank; A19, slurry pump; B1, water washing tank; B2, top drive agitator; B3, liquid level controller 2; B4, slurry inlet; B5, water inlet 3; B6, water inlet 4; B7, maintenance manhole 2; B8, exhaust gas outlet 2; B9, overflow interface 2;

B10, slurry outlet 2; B11, emptying interface 2; B12, pipeline flowmeter 3; B13, pipeline flowmeter 4; B14, pipeline flowmeter 5; B15, slurry discharge pipe; B16, variable frequency booster pump; C1, washing liquid storage tank; C2, concentrated slurry storage tank; C3, eddy current separator; C4, ash discharge pipe; C5, exhaust gas outlet 3;

C6, maintenance manhole three; C7, washing liquid discharge outlet; C8, washing liquid discharge pipe; C9, ash outlet; C10, solenoid valve two; C11, slurry discharge outlet; C12, slurry discharge pipe; C13, solenoid valve three; C3-1, water-washed slurry access pipe; C3-2, connecting conduit; C3-3, inverted cone pipe; C3-4, annular access main pipe; C3-5, solenoid valve four; C3-6, variable frequency slurry pump.

DETAILED DESCRIPTION

The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example:

Please refer to Figures 1 to 5. The embodiment of the present invention provides an energy-saving and efficient fly ash water washing and dechlorination system, including:

The fly ash pulping unit is used to pre-dissolve the weighed raw fly ash, which 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 raw fly ash slurry. The multi-stage water washing unit is composed of a plurality of top-driven stirring water washing devices;

A multi-stage eddy current separation unit is used to perform multi-stage three-phase separation on the primary pulp after water washing; the multi-stage eddy current separation unit is composed of a plurality of integrated eddy current three-phase separation devices;

The wastewater treatment unit is used for wastewater treatment, and includes a wastewater treatment module and a reuse water pool, wherein the wastewater treatment module includes but is not limited to a multi-stage physical and chemical sedimentation system, an MBR system, and a constructed wastewater combination module. The wastewater treatment unit receives the sedimentation sludge from the deweighting unit and the wastewater from the waste gas treatment unit, and treats them together. The treated effluent is used as reuse water for the pulping unit, and the dewatered sludge is properly handled by outsourcing;

The fly ash water washing and dechlorination system also 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-frame filter press device and a centrifugal separation device. The mechanical solid-liquid separation unit separates the three-stage water-washed slurry into filtrate and solid residue, and all the filtrate is used as the inlet water of the secondary water washing tank for reflux treatment, and the solid residue can achieve a dechlorinated fly ash with a chlorine content of ≤2% and a water content of 30% to 50%, thereby completing energy-saving and efficient fly ash dechlorination, which can be outsourced for further terminal disposal;

The fly ash water washing and dechlorination system also includes a weight removal unit for removing heavy metals, which includes a reaction module and a weight removal sedimentation tank, wherein the reaction module includes but is not limited to a flocculation sedimentation device and an electrolysis device, and the fly ash water washing and dechlorination system also includes an evaporation crystallization unit for evaporation crystallization, which includes an evaporation crystallization device and a condensation water tank, wherein the evaporation crystallization device includes but is not limited to an MVR device, a membrane concentration + MVR device, and a membrane salt separation + membrane concentration + MVR device. The primary washing liquid prepared in the primary eddy current separation unit is introduced into the weight removal unit for weight removal treatment, and the supernatant after weight removal is transported to the evaporation crystallization unit for treatment, and finally it is resourced into an industrial salt product through the evaporation crystallization unit, and the condensed water generated by the evaporation crystallization unit is temporarily stored in the condensation water tank as supplementary water for the process link. When the supplementary water is insufficient, it is supplemented by clean water (including but not limited to tap water, clean surface environmental water, clean groundwater, etc.); the precipitated sludge after weight removal is pumped to the wastewater treatment unit for treatment, and the waste gas generated during the weight removal process is treated by the waste gas treatment system;

The fly ash water washing and 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, wherein the waste gas treatment module includes but is not limited to a spray tower and an activated carbon adsorption device. The waste gas treatment unit collects the waste gas from the fly ash pulping unit, the waste gas from the multi-stage water washing unit, the waste gas from the multi-stage eddy current separation unit, the waste gas from the weight removal unit, and the waste water treatment unit through a waste gas collection main pipe for treatment, and the waste water generated by the treatment is connected to the waste water treatment unit, and the treated waste gas is discharged into the air.

The precise control pre-dissolution device includes a pulping tank A1, a top-driven variable frequency agitator A2 and a liquid level controller A3. The top of the pulping tank A1 is provided with 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 left to right. The side of the pulping tank A1 is provided with an overflow interface A9 and a slurry outlet A10 from top to bottom. The bottom of the pulping tank A1 is provided with an emptying interface A11; the top of the second water inlet A6 is connected to a pipeline flowmeter A12 for measuring the water inlet, and the top of the pipeline flowmeter A12 is installed with an electromagnetic valve A13 for cooperating with it to control the water inlet, the top of the water inlet A5 is provided with a pipeline flowmeter A14 for measuring the water inlet, and the pipeline flowmeter A14 and the reuse water pool of the wastewater treatment unit are connected. The intermediate water pump is connected to control the total amount of water intake, the input end of the fly ash inlet A4 is connected to a metering scale system A15 for controlling the ash intake amount, the top drive variable frequency agitator A2 is installed on the top of the pulping tank A1, the liquid level controller A3 is installed inside the pulping tank A1 to read the liquid level signal in the pulping 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 liquid level controller A3 and the top drive variable frequency agitator A2 respectively, the slurry discharge port A10 is connected to a primary slurry discharge pipe A17 at one end away from the pulping tank A1, and the other end of the primary slurry discharge pipe A17 is connected to a primary slurry buffer tank A18, and a slurry pump A19 is provided in the primary slurry buffer tank A18 for transporting the prepared primary slurry to the subsequent water washing unit.

Specifically, a certain amount of fly ash raw ash is weighed through the metering scale system A15, and is put into the pulping tank A1 through the fly ash inlet A4. At the same time, part of the washing liquid of the secondary eddy current separation unit is introduced into the pulping tank A1 through the water inlet A6. The mass ratio of the introduced fly ash raw ash to the washing liquid is controlled at 0.5-1.5 through the control of the pipeline flow meter A12 and the solenoid valve A13. The top drive variable frequency agitator A2 is started to mix the fly ash raw ash and the washing liquid. At the same time, the treated reclaimed water of the wastewater treatment unit is continuously injected into the pulping tank A1, and the mass ratio of the fly ash raw ash to the reclaimed water is controlled at 1.0-2.0 through the control of the pipeline flow meter A14 and the water pump in the regeneration water tank. The material intake of the incoming water inlet A6 and the fly ash inlet A4 controls the mass ratio of the total incoming water to the fly ash at 1.5-2.5; and the liquid level change signal in the pulping tank is read through the liquid level controller A3, and the signal is transmitted to the speed controller A16 to adjust the stirring intensity of the top drive variable frequency agitator A2 to ensure the pulping effect; in this process, the exhaust gas in the pulping tank A1 is discharged through the exhaust gas outlet A8 and enters the exhaust gas treatment system for treatment; after 10-30 minutes of stirring and pulping, a uniform pre-dissolved primary slurry is obtained, and the pre-dissolved primary slurry is introduced into the primary slurry buffer tank A18 through the slurry outlet A10 and the primary slurry discharge pipe A17, and the pre-dissolved primary slurry is transported to the subsequent first-level water washing unit by the slurry pump A19 therein.

The top-driven stirring water washing device includes a water washing tank B1, a top-driven agitator B2 and a liquid level controller B3. From left to right, the top of the water washing tank B1 is provided with a mortar inlet B4, a water inlet B5, a water inlet B6, a maintenance manhole B7 and a waste gas outlet B8. The upper and lower ends of the side of the water washing tank B1 are respectively provided with an overflow interface B9 and a mortar outlet B10. The bottom of the water washing tank B1 is provided with an emptying interface B11, a mortar inlet B4, a water inlet B5, a water inlet B4 The top of B6 is respectively equipped with pipeline flowmeter three B12, pipeline flowmeter four B13, and pipeline flowmeter five B14 for measuring water volume. The end of slurry discharge outlet two B10 away from the water washing tank B1 is connected to B15, and the other end of B15 is connected to the input end of variable frequency booster pump B16, which is used to transport the water-washed slurry to the subsequent eddy current separation unit. The top drive agitator B2 is installed on the top of the water washing tank B1, and the liquid level controller two B3 is installed inside the water washing tank B1 to read the liquid level signal in the water washing tank B1.

Specifically, the pre-dissolved primary slurry prepared in the precise control pre-dissolving device is pumped into the water washing tank B1 through the slurry inlet B4, and all the remaining washing liquid of the secondary eddy current separation unit is also introduced into the water washing tank B1 through the water inlet four B6. The water pump in the condensation pool of the evaporation crystallization unit is started, and the supplementary water is continuously pumped into the water washing tank B1 through the water inlet three B5. By jointly reading the data of the pipeline flow meter three B12, 13 and the pipeline flow meter five B14, the corresponding control valve is used to realize the precise control of the amount of supplementary water, and the total The mass ratio of incoming water to primary slurry is controlled at 1.0-1.5. During this process, the waste gas in the water washing tank B1 is discharged through the waste gas outlet B8 and enters the waste gas treatment system for treatment. After 45-90 minutes of stirring and washing, the primary water-washed slurry is obtained, which is transported to the primary eddy current separation unit by the variable frequency booster pump B16 after passing through the slurry outlets B10 and B15. 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 issued to avoid frequent overflow.

During the secondary water washing, the primary concentrated slurry and the filtrate from the mechanical separation unit are respectively introduced into the water washing tank of the secondary water washing unit, and the mass ratio of the total incoming water to the concentrated slurry is controlled at 0.5-1.0 by controlling the amount of the filtrate introduced; after 45-90 minutes of stirring and water washing, the secondary water washing slurry is obtained and transported to the secondary eddy current separation unit by the variable frequency booster pump B16 in the secondary water washing unit, and the waste gas generated during the process is treated by the waste gas treatment system;

During the tertiary water washing, the secondary concentrated slurry obtained in the secondary eddy current separation unit and the condensed water in the evaporation crystallization unit are respectively introduced into the water washing tank of the tertiary water washing unit as supplementary water, and the mass ratio of the total incoming water to the secondary concentrated slurry is adjusted to be controlled at 0.5-1.0 by controlling the amount of the introduced supplementary water. After 45-90 minutes of stirring and washing, the tertiary water-washed slurry is obtained, and the waste gas generated during this period is treated by the waste gas treatment system.

The integrated eddy current three-phase separation device comprises a washing liquid storage tank C1, a concentrated slurry storage tank C2 and a plurality of eddy current separators C3 connected therebetween; an ash 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 opened solenoid valve C10 is provided on the ash discharge pipe C4; exhaust gas outlet C5 and inspection manhole C6 are provided on both sides of the top of the washing liquid storage tank C1, respectively; a washing liquid outlet C7 is provided at the middle and upper part of the washing liquid storage tank C1, and a washing liquid discharge pipe C8 connected to the washing liquid outlet C7; an ash outlet C9 is provided at the bottom of the washing liquid storage tank C1, and 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; a slurry outlet C11 is provided at the bottom of the concentrated slurry storage tank C2, and the bottom end of the slurry outlet C11 is connected to a slurry discharge pipe C12, and the slurry discharge A solenoid valve C13 for controlling the gravity flow of concentrated slurry to the subsequent receiving unit is installed at the other end of the pipe C12. A water-washing slurry access pipe C3-1 is provided on the upper side of the eddy current separator C3. A connecting conduit C3-2 for ascending clear liquid and air is provided on the top of the eddy current separator C3, and the connecting conduit C3-2 is connected to the washing liquid storage tank C1. An inverted cone pipe C3-3 for descending slurry is provided at the bottom of the eddy current separator C3, and the inverted cone pipe C3-3 is connected to the concentrated slurry storage tank C2. The water-washing slurry access pipes C3-1 of multiple eddy current separators C3 are all connected to a ring-shaped access main pipe C3-4. The side ends of the ring-shaped access main pipe C3-4 are sequentially connected to a solenoid valve C3-5 and a variable frequency slurry pump C3-6, so as to control the slurry amount from the top-driven stirring and water-washing device and the eddy current intensity in the eddy current separator C3.

Specifically, when performing the primary eddy current separation, the primary water-washed slurry obtained by the primary water-washing unit is evenly distributed to a plurality of groups of eddy current separators C3 through the annular access main pipe C3-4 for three-phase efficient separation, and the eddy current intensity in the eddy current separator C3 is controlled by adjusting the pressure of the variable frequency booster pump B16 in the primary water-washing unit connected to the primary eddy current separation and the pressure of the solenoid valve four C3-5; the separated ascending clear liquid and air are introduced into the washing liquid storage tank C1 through the connecting conduit C3-2, and the separated descending concentrated slurry is introduced into the concentrated slurry storage tank C2 through the inverted cone pipe C3-3; During this process, the waste gas in the washing liquid storage tank C1 is discharged through the waste gas outlet C5 to enter the waste gas treatment system for treatment; the separated primary washing liquid flows by gravity into the subsequent weight removal unit through the washing liquid outlet C7 and the washing liquid discharge pipe C8; the separated primary concentrated slurry flows by gravity to the subsequent secondary water washing unit through the slurry outlet C11 and the slurry discharge pipe C12, and its flow is controlled by the electromagnetic valve C13; the slurry deposited in the washing liquid storage tank C1 is discharged regularly to the concentrated slurry storage tank C2 through the ash outlet C9 and the ash discharge pipe C4, and the discharge interval is 6-48h;

During the secondary eddy current separation treatment, the secondary water-washed slurry prepared in the secondary water-washing unit is pumped into the eddy current separator C3 in the secondary eddy current separation unit for efficient three-phase separation. The separated secondary washing liquid flows by gravity to the pulping unit and the primary water-washing unit. The data of the pipeline flow meter A12 in the pulping unit and the pipeline flow meter B12 in the primary water-washing unit are read, and the distribution ratio of the secondary washing liquid reflux to the pulping unit and the primary water-washing unit is adjusted as needed by controlling the solenoid valve A13 in the pulping unit. The waste gas generated during this period is treated by the waste gas treatment system, and the separated secondary concentrated slurry flows into the subsequent tertiary water-washing unit by its own weight.

An energy-saving and efficient fly ash water washing and dechlorination method comprises the following steps:

S1, pre-dissolution: adding a certain amount of raw fly ash to the pulping unit, adding part of the washing liquid from the secondary eddy current separation unit to the fly ash pulping unit for stirring, then adding the reclaimed water collected from the wastewater treatment unit to the fly ash pulping unit, stirring again, to obtain a uniform pre-dissolved primary slurry, and finally transporting the pre-dissolved primary slurry to the subsequent primary water washing unit;

S2, primary water washing: the pre-dissolved primary slurry in S1 is transported to the primary water washing unit, and at the same time, all the remaining washing liquid of the secondary eddy current separation unit is added to the primary water washing unit, and the water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary water washing unit to obtain primary water-washed slurry, and then the obtained primary water-washed slurry is transported to the primary eddy current separation unit;

S3, primary eddy current separation: the primary water-washed slurry in S2 is transported to the primary eddy current separation unit for separation, and then the separated ascending clear liquid and air are separated from the separated descending concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The separated primary washing liquid flows by gravity into the subsequent weight removal unit, and the separated primary concentrated slurry flows by gravity to the subsequent secondary water washing unit;

S4, primary washing liquid treatment: the primary washing liquid in S3 is introduced into the de-weighting unit for de-weighting treatment, and the supernatant after de-weighting is transported to the evaporation crystallization unit for treatment, and finally it is resourced into industrial salt products through the evaporation crystallization unit, while the condensed water generated by the evaporation crystallization unit is temporarily stored in the condensed water pool as supplementary water for the process link, and the precipitated sludge after de-weighting is pumped to the wastewater treatment unit for treatment, and the waste gas generated during the de-weighting process is treated by the waste gas treatment system;

S5, secondary water washing: the primary concentrated slurry in S3 and the filtrate from the mechanical separation unit are introduced into the secondary water washing unit, and after stirring and washing, the secondary water-washed slurry is obtained, and then the secondary water-washed slurry is transported to the secondary eddy current separation unit;

S6, secondary eddy current separation: the secondary water-washed slurry in S5 is pumped to the secondary eddy current separation unit for efficient three-phase separation, and the separated secondary washing liquid flows by gravity to the pulping unit and the primary water washing unit, and the distribution ratio of the secondary washing liquid back to the pulping unit and the primary water washing unit is adjusted as needed, and the separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit;

S7, tertiary water washing: the secondary concentrated slurry in S6 and the condensed water of the evaporation crystallization unit are introduced into the tertiary water washing unit as supplementary water, and after stirring and washing, the tertiary water-washed slurry is obtained;

S8, mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the tertiary water-washed slurry into filtrate and solid residue. The filtrate is all refluxed as the influent of the secondary water-washing unit, and the solid residue is dechlorinated fly ash;

S9. Waste gas supporting treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy current separation unit, the weight removal unit, and the waste water treatment unit through the waste gas collection main pipe, and connects the waste water generated by the treatment to the waste water treatment unit, and the treated waste gas is discharged into the air;

S10. Wastewater treatment: The wastewater treatment unit receives the precipitated sludge from the weight removal unit and the wastewater from the waste gas treatment unit, and treats them together. The treated effluent is used as recycled water in the pulping unit, and the dewatered sludge is retained for subsequent treatment.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. An energy-saving and efficient fly ash water washing and dechlorination system, characterized by comprising: The fly ash pulping unit is used to pre-dissolve the weighed raw fly ash, which 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 raw fly ash slurry. The multi-stage water washing unit is composed of a plurality of top-driven stirring water washing devices; A multi-stage eddy current separation unit is used to perform multi-stage three-phase separation on the primary pulp after water washing; the multi-stage eddy current separation unit is composed of a plurality of integrated eddy current three-phase separation devices; The wastewater treatment unit is used for wastewater treatment, which includes a wastewater treatment module and a reuse water pool, wherein the wastewater treatment module includes but is not limited to a multi-stage physical and chemical sedimentation system, an MBR system, and a constructed wastewater combination module. 2. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, characterized in that the precise control pre-dissolution device comprises a pulping tank (A1), a top-driven variable frequency agitator (A2) and a liquid level controller (A3), the top of the pulping tank (A1) is provided with a fly ash inlet (A4), a water inlet one (A5), a water inlet two (A6), a maintenance manhole one (A7) and an exhaust gas outlet one (A8) from left to right, and the side of the pulping tank (A1) is provided with a fly ash inlet (A4), a water inlet one (A5), a water inlet two (A6), a maintenance manhole one (A7) and an exhaust gas outlet one (A8) from top to bottom. An overflow interface (A9) and a slurry discharge port (A10) are sequentially opened at the bottom of the slurry tank (A1), and an emptying interface (A11) is opened at the bottom of the slurry tank (A1); the top of the second water inlet (A6) is connected to a pipeline flow meter (A12) for measuring the water inflow, and the top of the pipeline flow meter (A12) is equipped with a solenoid valve (A13) for cooperating with it to control the water inflow; the top of the first water inlet (A5) is equipped with a pipeline flow meter (A14) for measuring the water inflow, and the pipeline flow meter (A12) is equipped with a solenoid valve (A13) for cooperating with it to control the water inflow. The meter 2 (A14) is connected to a water pump in a reuse water pool of a wastewater treatment unit to control the total amount of water inflow; the input end of the fly ash inlet (A4) is connected to a metering scale system (A15) for controlling the amount of ash inflow; the top-driven variable frequency agitator (A2) is installed on the top of the pulping tank (A1); the liquid level controller 1 (A3) is installed inside the pulping tank (A1) to read the liquid level signal in the pulping tank (A1); a speed regulating device is installed on the top of the top-driven variable frequency agitator (A2) A controller (A16) is provided, and the speed controller (A16) is electrically connected to a liquid level controller (A3) and a top-driven variable frequency agitator (A2) respectively; one end of the slurry discharge port (A10) away from the pulping tank (A1) is connected to a primary slurry discharge pipe (A17), and the other end of the primary slurry discharge pipe (A17) is connected to a primary slurry buffer tank (A18); a slurry pump (A19) is provided in the primary slurry buffer tank (A18) for conveying the prepared primary slurry to a subsequent water washing unit. 3. An energy-saving and efficient fly ash washing and dechlorination system according to claim 1, characterized in that the top-driven stirring washing device comprises a washing tank (B1), a top-driven agitator (B2) and a second liquid level controller (B3); the top of the washing tank (B1) is provided with a mortar inlet (B4), a third water inlet (B5), a fourth water inlet (B6), a second inspection manhole (B7) and a second exhaust outlet (B8) from left to right; the upper and lower ends of the side of the washing tank (B1) are respectively provided with an overflow interface (B9) and a second mortar outlet (B10); the bottom of the washing tank (B1) is provided with a second emptying interface (B11); the mortar inlet A pipeline flow meter 3 (B12), a pipeline flow meter 4 (B13) and a pipeline flow meter 5 (B14) for measuring the water volume are installed at the top of the water inlet 3 (B4), the water inlet 3 (B5) and the water inlet 4 (B6), respectively; one end of the slurry outlet 2 (B10) away from the water washing tank (B1) is connected to (B15); the other end of (B15) is connected to the input end of the variable frequency booster pump (B16) for conveying the water-washed slurry to the subsequent eddy current separation unit; the top-driven agitator (B2) is installed on the top of the water washing tank (B1); and the liquid level controller 2 (B3) is installed inside the water washing tank (B1) for reading the liquid level signal in the water washing tank (B1). 4. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, characterized in that the integrated eddy current three-phase separation device comprises a washing liquid storage tank (C1), a concentrated slurry storage tank (C2) and a plurality of eddy current separators (C3) connected therebetween, an ash 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 opened electromagnetic valve 2 (C10) is provided on the ash discharge pipe (C4), exhaust gas outlet 3 (C5) and inspection manhole 3 (C6) are respectively provided on both sides of the top of the washing liquid storage tank (C1), and the washing liquid storage tank (C1) is provided with a plurality of eddy current separators (C3) connected therebetween. A washing liquid outlet (C7) and a washing liquid discharge pipe (C8) connected to the washing liquid outlet (C7) are provided in the middle and upper part; an ash outlet (C9) is provided at the bottom of the washing liquid storage tank (C1); 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); a slurry outlet (C11) is provided at the bottom of the concentrated slurry storage tank (C2); the bottom end of the slurry outlet (C11) is connected to a slurry discharge pipe (C12), and the other end of the slurry discharge pipe (C12) is installed with a solenoid valve three (C13) for controlling the concentrated slurry to flow to the subsequent receiving unit. 5. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 4, characterized in that a water-washing slurry access pipe (C3-1) is provided on the upper side of the eddy current separator (C3), a connecting conduit (C3-2) for ascending clear liquid and air is provided on the top of the eddy current separator (C3), and the connecting conduit (C3-2) is connected to the washing liquid storage tank (C1), an inverted cone pipe (C3-3) for descending slurry is provided at the bottom of the eddy current separator (C3), and the inverted cone pipe (C3-3) is connected to the concentrated slurry storage tank (C2), and the water-washing slurry access pipes (C3-1) of multiple eddy current separators (C3) are all connected to an annular access main pipe (C3-4), and the side ends of the annular access main pipe (C3-4) are sequentially connected to a solenoid valve four (C3-5) and a variable frequency slurry pump (C3-6), so as to control the slurry amount from the top driven stirring water washing device and the eddy current intensity in the eddy current separator (C3). 6. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, characterized in that the dechlorination system also includes a mechanical solid-liquid separation unit for mud and 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 device and a centrifugal separation device. 7. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, characterized in that the dechlorination system also includes a weight removal unit for removing heavy metals, which includes a reaction module and a weight removal sedimentation tank, wherein the reaction module includes but is not limited to a flocculation sedimentation device and an electroanalysis device. 8. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, characterized in that the dechlorination system also includes an evaporation crystallization unit for evaporation crystallization, which includes an evaporation crystallization device and a condensation water pool, wherein the evaporation crystallization device includes but is not limited to an MVR device, a membrane concentration + MVR device, and a membrane salt separation + membrane concentration + MVR device. 9. An energy-saving and efficient fly ash water washing and dechlorination system according to claim 1, 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, wherein the waste gas treatment module includes but is not limited to a spray tower and an activated carbon adsorption device. 10. A fly ash water washing and dechlorination method based on the fly ash water washing and dechlorination system according to claim 1, characterized in that it comprises the following steps: S1, pre-dissolution: adding a certain amount of raw fly ash to the pulping unit, adding part of the washing liquid from the secondary eddy current separation unit to the fly ash pulping unit for stirring, then adding the reclaimed water collected from the wastewater treatment unit to the fly ash pulping unit, stirring again, to obtain a uniform pre-dissolved primary slurry, and finally transporting the pre-dissolved primary slurry to the subsequent primary water washing unit; S2, primary water washing: the pre-dissolved primary slurry in S1 is transported to the primary water washing unit, and at the same time, all the remaining washing liquid of the secondary eddy current separation unit is added to the primary water washing unit, and the water pump in the condensation tank of the evaporation crystallization unit is started to send the internal water into the primary water washing unit to obtain primary water-washed slurry, and then the obtained primary water-washed slurry is transported to the primary eddy current separation unit; S3, primary eddy current separation: the primary water-washed slurry in S2 is transported to the primary eddy current separation unit for separation, and then the separated ascending clear liquid and air are separated from the separated descending concentrated slurry to obtain primary washing liquid and primary concentrated slurry respectively. The separated primary washing liquid flows by gravity into the subsequent weight removal unit, and the separated primary concentrated slurry flows by gravity to the subsequent secondary water washing unit; S4, primary washing liquid treatment: the primary washing liquid in S3 is introduced into the de-weighting unit for de-weighting treatment, and the supernatant after de-weighting is transported to the evaporation crystallization unit for treatment, and finally it is resourced into industrial salt products through the evaporation crystallization unit, while the condensed water generated by the evaporation crystallization unit is temporarily stored in the condensed water pool as supplementary water for the process link, and the precipitated sludge after de-weighting is pumped to the wastewater treatment unit for treatment, and the waste gas generated during the de-weighting process is treated by the waste gas treatment system; S5, secondary water washing: the primary concentrated slurry in S3 and the filtrate from the mechanical separation unit are introduced into the secondary water washing unit, and after stirring and washing, the secondary water-washed slurry is obtained, and then the secondary water-washed slurry is transported to the secondary eddy current separation unit; S6, secondary eddy current separation: the secondary water-washed slurry in S5 is pumped to the secondary eddy current separation unit for efficient three-phase separation, and the separated secondary washing liquid flows by gravity to the pulping unit and the primary water washing unit, and the distribution ratio of the secondary washing liquid back to the pulping unit and the primary water washing unit is adjusted as needed, and the separated secondary concentrated slurry flows by gravity to the subsequent tertiary water washing unit; S7, tertiary water washing: the secondary concentrated slurry in S6 and the condensed water of the evaporation crystallization unit are introduced into the tertiary water washing unit as supplementary water, and after stirring and washing, the tertiary water-washed slurry is obtained; S8, mechanical solid-liquid separation: The mechanical solid-liquid separation unit separates the tertiary water-washed slurry into filtrate and solid residue. The filtrate is all refluxed as the influent of the secondary water-washing unit, and the solid residue is dechlorinated fly ash; S9. Waste gas supporting treatment: The waste gas treatment unit collects the waste gas from the pulping unit, the multi-stage water washing unit, the multi-stage eddy current separation unit, the weight removal unit, and the waste water treatment unit through the waste gas collection main pipe, and connects the waste water generated by the treatment to the waste water treatment unit, and the treated waste gas is discharged into the air; S10. Wastewater treatment: The wastewater treatment unit receives the precipitated sludge from the weight removal unit and the wastewater from the waste gas treatment unit, and treats them together. The treated effluent is used as recycled water in the pulping unit, and the dewatered sludge is retained for subsequent treatment.