Treatment system and method for waste incineration fly ash water washing liquid in conjunction with flue gas purification

Abstract

The application discloses a kind of waste incineration fly ash water washing liquid collaborative flue gas purification processing system and method, the system includes with incineration plant main flue connection's semi-dry desulfurization tower, dust collector, ash storehouse, water washing tank, buffer tank, water preheater, wet scrubber, method is the garbage incineration fly ash collected in system is transported to water washing tank and is washed with dosing water, obtains water washing liquid and desalted fly ash;Utilize wet scrubber to spray fly ash water washing liquid, recycle tail flue gas waste heat and deeply remove remaining acid gas in flue gas, concentrate water washing liquid to reduce amount, control spray amount to adjust concentration ratio to realize the precipitation and solid-liquid separation of chlorides;The water washing liquid after concentration is introduced into semi-dry desulfurization tower, and the water washing liquid is atomized into fine droplets by rotary atomizer, and is contacted with hot flue gas to be steamed dry while absorbing acid gas in flue gas, realize water washing liquid zero discharge and collaborative flue gas purification.The application solves the high energy consumption problem of fly ash water washing liquid processing, and improves the resource utilization rate of water washing liquid.

Description

Technical Field

[0001] This invention belongs to the field of high-salt wastewater treatment technology, specifically relating to a treatment system and method for the synergistic purification of flue gas from waste incineration fly ash washing liquid. Background Technology

[0002] The incineration process generates a large amount of fly ash, which is classified as hazardous waste due to its high concentration of chloride salts (approximately 10-30% by mass), alkaline earth metals, and heavy metals. High chloride content is a key factor restricting the stabilization and resource utilization of fly ash. It leads to a decrease in the strength of solidified fly ash products and promotes the leaching of heavy metals, while also exacerbating corrosion of high-temperature processing equipment and increasing the load on flue gas purification systems, thus limiting the application of fly ash in building materials. Water washing can transfer soluble substances from fly ash to the washing solution, effectively removing chloride from the fly ash and facilitating subsequent stabilization and resource utilization.

[0003] The fly ash washing process generates a large amount of high-salt wastewater, known as fly ash washing liquid, in which some heavy metals are leached. Fly ash washing liquid is characterized by high salt content, high alkalinity, and trace elements; direct discharge of fly ash washing liquid will cause extremely serious harm to the ecological environment. Existing washing liquid treatment technologies mainly use evaporation crystallization processes to purify and separate chlorine and alkali from the washing liquid to obtain industrial salt products. However, evaporation crystallization equipment is complex and energy-intensive. Furthermore, calcium and magnesium ions in the washing liquid cause scaling in the evaporator crystallizer, resulting in high overall operating costs.

[0004] Currently, mainstream waste incineration plants mainly use a combination of SNCR, semi-dry desulfurization, and bag filter dust collection processes to remove pollutants from flue gas. Among them, semi-dry desulfurization removes acidic gases such as HCl and SO2 from flue gas by injecting alkaline slurry such as Ca(OH)2. Since the removal efficiency of semi-dry desulfurization is not as high as that of wet desulfurization, excessive lime slurry is often injected to ensure the flue gas purification effect. This results in a large amount of unreacted alkaline substances such as Ca(OH)2 accumulating in the fly ash, which increases the amount of fly ash and the overall alkalinity of fly ash, further increasing the cost of flue gas purification and the difficulty of disposing of washing liquid. Summary of the Invention

[0005] To address at least one of the aforementioned problems, this invention provides a treatment system and method for co-processing waste incineration fly ash washing liquid with flue gas purification. This method is a highly efficient and low-energy-consumption disposal method for waste incineration fly ash washing liquid, which, in conjunction with in-plant flue gas purification devices, achieves resource recovery and zero discharge of the washing liquid.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] A first aspect of the present invention provides a treatment system for the concentration and reduction of waste incineration fly ash washing liquid, combined with flue gas purification, the treatment system comprising:

[0008] A washing tank is connected to an ash silo. The washing tank is connected to process water through a process water inlet and to reagents through a reagent inlet. The tank is equipped with a stirring device and a solid-liquid separation device to separate the solid and liquid to obtain washing liquid and fly ash after washing and desalination.

[0009] A buffer tank, located between the washing tank and the wet scrubbing tower, is used to store the washing liquid obtained from the separation in the washing tank.

[0010] In a wet scrubbing tower, the washing liquid in the buffer tank is pumped into the slurry pool of the wet scrubbing tower. A demister is installed at the top of the wet scrubbing tower, and a spraying device consisting of pressure nozzles is installed in the middle of the wet scrubbing tower. The washing liquid in the slurry pool is pumped to the pressure nozzles by a circulating pump for spraying and concentration. The concentrated fly ash washing liquid is pumped into a semi-dry desulfurization tower through an outlet pump.

[0011] In a semi-dry desulfurization tower, flue gas enters through the inlet flue. The fly ash washing liquid concentrated in the wet scrubbing tower enters the semi-dry desulfurization tower and mixes with the desulfurization slurry. The mixture then enters the atomizer and is atomized into fine droplets to absorb acidic gases in the flue gas entering the semi-dry desulfurization tower. An ash hopper is provided at the bottom of the semi-dry desulfurization tower to collect desulfurization ash.

[0012] The dust collector is connected to the semi-dry desulfurization outlet flue and is used to separate fly ash from the flue gas. The flue gas after fly ash separation enters from the bottom of the wet scrubbing tower, is purified by water washing liquid sprayed through the pressure nozzles in the middle of the wet scrubbing tower, and the clean flue gas flows out through the flue gas outlet at the top of the wet scrubbing tower.

[0013] The ash silo receives desulfurization ash from the semi-dry desulfurization tower and fly ash separated by the dust collector.

[0014] Furthermore, a feedwater preheater is installed between the buffer tank and the wet scrubbing tower. The feedwater preheater is connected to the economizer hot water to exchange heat with the washing liquid coming out of the buffer tank.

[0015] Furthermore, the slurry tank at the bottom of the wet scrubbing tower is equipped with a conductivity meter and a level meter for online monitoring of the concentration ratio. The concentration ratio is controlled by adjusting the flow rates of the inlet and outlet pumps and the circulation pump to promote the saturation precipitation of chloride salts. The demister at the top of the wet scrubbing tower is a wire mesh demister.

[0016] Furthermore, the atomizer in the semi-dry desulfurization tower is a rotary atomizer.

[0017] Furthermore, the spray device is provided with one or more sets of pressure nozzles; the spray layer arranged in the wet scrubbing tower is 1 to 2 layers, each layer consisting of several pressure nozzles;

[0018] The solid-liquid separation device is one or a combination of a hydrocyclone, a centrifuge, or a vacuum filter.

[0019] A second aspect of the present invention provides a method for treating waste incineration fly ash washing liquid by concentration and volume reduction in conjunction with flue gas purification based on the system described in the first aspect, comprising the following steps:

[0020] The fly ash collected by the semi-dry desulfurization tower and dust collector is transferred to the ash storage silo.

[0021] The fly ash in the ash silo is transferred to the washing tank. The fly ash is mixed with process water in the washing tank, and the agent is added and stirred for washing. The solid-liquid separator in the washing tank is used to separate the solid and liquid to obtain the impurity-removed and softened washing liquid and the desalinated fly ash.

[0022] The washing liquid is transported to a buffer tank and then pumped to the slurry pool of the wet scrubbing tower via an inlet pump. The washing liquid is used as the spray liquid in the wet scrubbing tower and is pumped to the top of the wet scrubbing tower by a circulating pump and sprayed downwards. It comes into countercurrent contact with the low-temperature flue gas at the tail end, and the water in the washing liquid is evaporated by the waste heat of the flue gas, thereby achieving concentration and volume reduction. The concentration ratio is controlled by adjusting the flow rates of the inlet and outlet pumps and the circulating pump of the wet scrubbing tower, which promotes the saturation precipitation of chloride salts and solid-liquid separation.

[0023] The concentrated washing liquid is transported to a semi-dry desulfurization tower, mixed with desulfurization slurry, and atomized into droplets by a rotary atomizer. The droplets come into contact with the high-temperature flue gas input from the main flue of the incinerator. The water evaporates rapidly, and the alkaline substances in the droplets react with the acidic gases in the flue gas. The solid product, desulfurization ash, after evaporation falls into the ash hopper, and is then transferred and collected by a dust collector. The flue gas further enters the dust collector to remove fly ash, which enters the ash silo. The flue gas after dust removal enters the wet scrubbing tower, achieving zero wastewater discharge.

[0024] Furthermore, the reagent is one or a combination of calcium hydroxide, sodium hydroxide, sodium carbonate, and sodium sulfide; the amount of reagent added is 5-10% of the fly ash mass.

[0025] Furthermore, the stirring speed inside the washing tank is 50~200 rpm, the water-to-solid mass ratio is 3~10, and the stirring time is 30~120 min.

[0026] Furthermore, the atomizer rotates at a speed of 10,000 to 15,000 rpm, and the liquid-to-gas ratio is 0.8 to 2.0 L / Nm³. 3 The droplet size is 50~250μm.

[0027] Furthermore, the atomized liquid is a mixture of desulfurization slurry lime milk and fly ash washing liquid concentrated alkaline solution, with the total solid mass fraction in the desulfurization slurry ranging from 15% to 25% and the pH range from 8 to 11.

[0028] Furthermore, the residence time of the flue gas in the wet scrubbing tower is 10-20 seconds, the atomization pressure of the pressure nozzle is 0.1-1.0 MPa, the droplet size range of the atomized water scrubbing liquid is 500-2000 μm, and the droplets are sprayed into the tower from top to bottom; the total mass fraction of solids in the outlet concentrated alkali solution is 40%-60%.

[0029] Furthermore, the concentrated washing liquid has a solids mass fraction of 20% to 45%; it is added to the desulfurization slurry as makeup water, and the total solids mass fraction in the desulfurization slurry after mixing is 15% to 25%.

[0030] Beneficial effects of the present invention

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The fly ash collected from the semi-dry desulfurization tower and dust collector is transferred to an ash silo for temporary storage, and then transferred to a washing tank as needed. Chemicals are added to the washing tank to remove soluble salts from the fly ash. Solid-liquid separation yields desalinated fly ash and softened, impurity-removed washing liquid. The washing liquid is pumped into a buffer tank, and the outlet washing liquid is preheated by a feedwater preheater and sent to a wet scrubbing tower. The washing liquid, used as the spray liquid in the wet scrubbing tower, is pumped to the top of the tower by a circulating pump and sprayed downwards, where it meets the tail end of the scrubbing process. In a counter-current process, low- and medium-temperature flue gas is contacted, utilizing the waste heat of the flue gas to evaporate the water in the washing liquid, achieving concentration and volume reduction. Simultaneously, the alkaline components in the washing liquid further absorb acidic gases such as SO2, HCl, SO3, and CO2 from the flue gas. The flue gas exits the wet scrubbing tower after passing through a spray layer and a demister, thus achieving purification. By adjusting the inlet and outlet pump flow rates and spray volume, and monitoring the conductivity in the slurry tank, the concentration ratio of the washing liquid is controlled, promoting the precipitation of chloride salts and solid-liquid separation. The concentrated washing liquid is introduced into a semi-dry desulfurization tower, mixed with the desulfurization slurry, and atomized into fine droplets by a rotary atomizer. The atomized droplets contact the high-temperature flue gas, causing rapid evaporation of water. Simultaneously, the alkaline substances in the droplets undergo absorption reactions with the acidic gases (SO2, HCl, SO3, CO2) in the flue gas. Part of the evaporated solid product falls into the ash hopper at the bottom of the semi-dry desulfurization tower, while the rest is collected with the flue gas in a dust collector, achieving full utilization and zero emission of the washing liquid, thus synergistically purifying the flue gas.

[0033] This application's solution is based on a wet scrubbing tower to concentrate fly ash washing liquid. It utilizes the waste heat from the flue gas at the incinerator's tail end to evaporate and concentrate the washing liquid, reducing its volume and improving energy efficiency while lowering the energy consumption of traditional evaporation and crystallization processes. The fly ash washing liquid replaces part of the desulfurizing agent, improving the utilization rate of alkaline desulfurization absorbent, reducing the overall reagent usage of the system, and increasing flue gas purification efficiency. After desalination, the chlorine content in the fly ash is significantly reduced to meet national standards, allowing for safe resource recovery or recycling. Simultaneously, the concentrated chloride salts can be separated and recovered to obtain industrial salt products. The incinerator utilizes existing facilities to achieve on-site treatment of the fly ash washing liquid. All the fly ash washing liquid is converted into solids through atomization and evaporation, with no wastewater discharge, thus enhancing the incinerator's comprehensive fly ash treatment capacity. Attached Figure Description

[0034] Figure 1 This is a flowchart of the treatment system for the synergistic purification of waste incineration fly ash washing liquid concentration and volume reduction in Embodiment 1 of the present invention.

[0035] Figure 2 This is a schematic diagram of the composition and connection relationship of the wet scrubbing tower in the treatment system of waste incineration fly ash washing liquid concentration and reduction combined with flue gas purification in Embodiment 1 of the present invention.

[0036] Figure 3 This is a schematic diagram of the composition and connection relationship of the semi-dry desulfurization tower in the treatment system of waste incineration fly ash washing liquid concentration and reduction combined with flue gas purification in Embodiment 1 of the present invention.

[0037] Figure 4 Flowchart of the treatment system for the concentration and reduction of fly ash washing liquid from waste incineration and the synergistic purification of flue gas in Embodiment 2 of the present invention. Detailed Implementation

[0038] The following examples are used to illustrate preferred embodiments of the invention. Those skilled in the art will understand that the techniques disclosed in the examples represent techniques discovered by the inventors that can be used to implement the invention, and therefore can be considered preferred embodiments for implementing the invention. However, those skilled in the art should understand from this specification that many modifications can be made to the specific embodiments disclosed herein, still yielding the same or similar results, without departing from the spirit or scope of the invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all materials disclosed herein and cited therein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by ordinary experimentation by those skilled in the art. These equivalents will be included in the claims.

[0040] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0041] Example 1

[0042] Reference Appendix Figure 1-3 A treatment system for the concentration and reduction of fly ash washing liquid from waste incineration, combined with flue gas purification, is disclosed. The system includes: a washing tank for adding chemicals to the fly ash for washing, desalination, and separation of heavy metals; the washing tank is connected to an ash silo; the washing tank is connected to process water through a process water inlet and to chemicals through a chemical inlet; the tank is equipped with a stirring device and a solid-liquid separation device, and the solid-liquid separation yields washing liquid and fly ash after washing and desalination.

[0043] The buffer tank, located between the washing tank and the wet scrubbing tower, is used to store the washing liquid obtained from the separation in the washing tank.

[0044] In a wet scrubbing tower, the washing liquid in the buffer tank is pumped into the slurry tank of the wet scrubbing tower. A demister is installed at the top of the wet scrubbing tower, and a spraying device consisting of pressure nozzles is installed in the middle of the wet scrubbing tower. The washing liquid in the slurry tank is pumped to the pressure nozzles by a circulating pump for spraying and concentration. The concentrated fly ash washing liquid is pumped into a semi-dry desulfurization tower through an outlet pump. The spraying device consists of 1-2 spray layers, each consisting of several pressure nozzles.

[0045] The slurry tank at the bottom of the wet scrubbing tower is equipped with a conductivity meter and a level gauge for online monitoring of the concentration ratio. The concentration ratio is controlled by adjusting the flow rates of the inlet and outlet pumps and the circulation pump to promote the saturation precipitation of chloride salts. The demister at the top of the wet scrubbing tower is a wire mesh demister.

[0046] In a semi-dry desulfurization tower, flue gas enters through the inlet duct. The concentrated fly ash washing liquid from the wet scrubbing tower mixes with the desulfurization slurry and is atomized into fine droplets by an atomizer to absorb acidic gases from the flue gas entering the semi-dry desulfurization tower. An ash hopper is located at the bottom of the semi-dry desulfurization tower to collect the desulfurization ash, a solid product obtained from the desulfurization process. The atomizer is a rotary atomizer.

[0047] The semi-dry desulfurization tower is mainly used to receive the concentrated fly ash washing liquid from the wet scrubbing tower, mix it with the original desulfurization slurry in the semi-dry desulfurization tower and atomize it into fine droplets through a rotary atomizer, and absorb acidic gases in the flue gas of the main flue during the evaporation process.

[0048] The dust collector, connected to the semi-dry desulfurization outlet flue, is used to separate fly ash from the flue gas. The flue gas after fly ash separation enters from the bottom of the wet scrubbing tower. The flue gas enters from the bottom of the tower and comes into countercurrent contact with the liquid droplets. It is then purified by being sprayed with washing liquid through the pressure nozzles in the middle of the wet scrubbing tower, realizing the evaporation and concentration of the liquid droplets while deeply removing acidic gases in the flue gas. After that, it passes through a wire mesh demister to reduce the entrainment of liquid droplets in the liquid droplets. The clean flue gas flows out through the flue gas outlet at the top of the wet scrubbing tower.

[0049] The ash silo receives desulfurization ash from the semi-dry desulfurization tower and fly ash separated by the dust collector.

[0050] In different implementation schemes, the solid-liquid separation device can be selected from one or a combination of plate and frame filter press, hydrocyclone, centrifuge, vacuum filter, and belt filter.

[0051] Example 2

[0052] As an optimization, based on Example 1, a feedwater preheater is also installed between the buffer tank and the wet scrubbing tower. The feedwater preheater is connected to the economizer hot water, and the economizer hot water is used as a heat source to exchange heat with the washing liquid coming out of the buffer tank, thereby improving its evaporation and concentration efficiency, as shown in the attached figure. Figure 4 As shown.

[0053] Example 3

[0054] A method for treating waste incineration fly ash washing liquid by concentration and volume reduction in conjunction with flue gas purification includes the following specific steps:

[0055] (1) The fly ash collected by the semi-dry desulfurization tower and dust collector is transferred to the ash storage for temporary storage, and then transferred to the washing tank in a timely manner. The washing tank is filled with chemicals to remove soluble salts from the fly ash. The fly ash after desalination and the washing liquid after impurity removal and softening are obtained through solid-liquid separation. The fly ash after desalination can be further utilized for resource recovery.

[0056] (2) The washing liquid is pumped into the buffer tank, and the outlet of the buffer tank is connected to the feed water preheater. After being heated by hot water in the economizer, it is sent to the wet scrubbing tower. The washing liquid is pumped to the top of the wet scrubbing tower by the circulating pump and sprayed downwards. It comes into countercurrent contact with the low-temperature flue gas at the tail end. The water in the washing liquid is evaporated by the residual heat of the flue gas, and the concentration and volume reduction are achieved. At the same time, the alkaline components in the washing liquid further absorb the acidic gases in the flue gas. The flue gas leaves the wet scrubbing tower after passing through the spray layer and the demister and is purified. The concentration ratio of the washing liquid is controlled by adjusting the pump flow rate, spray volume and flue gas temperature, and monitoring the conductivity in the slurry tank. This promotes the saturation precipitation of chloride salts and solid-liquid separation to obtain concentrated washing liquid and salt crystals.

[0057] (3) The concentrated washing liquid is introduced into the semi-dry desulfurization tower and mixed with the original desulfurization slurry in the semi-dry desulfurization tower. It is then atomized into fine droplets by a rotary atomizer. The atomized droplets come into contact with the high-temperature flue gas, and the water evaporates rapidly. At the same time, the alkaline substances in the droplets react with the acidic gases in the flue gas. The solid products after evaporation fall into the ash hopper at the bottom of the semi-dry desulfurization tower, and some enter the dust collector with the flue gas for collection, so as to realize the full utilization of the washing liquid and the coordinated purification of the flue gas.

[0058] The semi-dry desulfurization tower uses a rotary atomizer with an atomizing disc rotation speed of 10,000~15,000 rpm and an atomization liquid-to-gas ratio of 0.8~2.0 L / Nm³.3 The droplet size is 50~250μm. The desulfurization slurry is a mixture of lime milk and concentrated alkaline solution from fly ash washing liquid. The total mass fraction of solids in the desulfurization slurry ranges from 15~25%, and the pH ranges from 8~11.

[0059] The internal agitator speed of the washing tank is 50~200 rpm, the liquid-to-solid mass ratio of the washing solution is 3~10, the stirring time is 30~120 min, and the agent added during the washing process is one or a combination of calcium hydroxide, sodium hydroxide, sodium carbonate, and sodium sulfide, with the amount of agent added being 5~10% of the fly ash mass.

[0060] The wet scrubbing tower has 1 to 2 spray layers, each consisting of several pressure nozzles. The pressure nozzles atomize the water washing liquid into 500 to 2000 μm droplets, which are then sprayed into the tower from top to bottom. The slurry pool at the bottom of the wet scrubbing tower is equipped with a level gauge and a conductivity meter to monitor the concentration ratio online. The concentration ratio is controlled by adjusting the inlet and outlet pump flow rates and the circulation pump flow rates to promote the saturation precipitation of chloride salts.

[0061] The flue gas purification effect achieved by semi-dry deacidification and wet scrubbing towers refers to the removal of acidic gases from flue gas, including SO2, HCl, SO3 and CO2.

[0062] This application organically combines the treatment of fly ash washing liquid from waste incineration with the flue gas purification process. It utilizes existing facilities within the incineration plant to co-process the fly ash washing liquid: the waste heat from the flue gas is recovered through spraying the washing liquid in a wet scrubbing tower to achieve concentration and volume reduction, while also removing acidic gases; the concentrated alkaline solution from the washing liquid is evaporated by atomization in a semi-dry desulfurization tower, achieving waste-to-waste treatment and zero wastewater discharge; the resulting industrial salt and dechlorinated fly ash can be further recycled. The solution is economically viable and solves the high energy consumption problem of fly ash washing liquid treatment.

[0063] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by this application.

Claims

1. A treatment system for the concentration and reduction of fly ash washing liquid from waste incineration, combined with flue gas purification, characterized in that, The processing system includes: A washing tank is connected to an ash silo. The washing tank is connected to process water through a process water inlet and to reagents through a reagent inlet. The tank is equipped with a stirring device and a solid-liquid separation device to separate the solid and liquid to obtain washing liquid and fly ash after washing and desalination. A buffer tank, located between the washing tank and the wet scrubbing tower, is used to store the washing liquid obtained from the separation in the washing tank. In a wet scrubbing tower, the washing liquid in the buffer tank is pumped into the slurry pool of the wet scrubbing tower. A demister is installed at the top of the wet scrubbing tower, and a spraying device consisting of pressure nozzles is installed in the middle of the wet scrubbing tower. The washing liquid in the slurry pool is pumped to the pressure nozzles by a circulating pump for spraying and concentration. The concentrated fly ash washing liquid is pumped into a semi-dry desulfurization tower through an outlet pump. In a semi-dry desulfurization tower, flue gas enters through the inlet flue. The fly ash washing liquid concentrated in the wet scrubbing tower enters the semi-dry desulfurization tower and mixes with the desulfurization slurry. The mixture then enters the atomizer and is atomized into fine droplets to absorb acidic gases in the flue gas entering the semi-dry desulfurization tower. An ash hopper is provided at the bottom of the semi-dry desulfurization tower to collect desulfurization ash. The dust collector is connected to the semi-dry desulfurization outlet flue and is used to separate fly ash from the flue gas. The flue gas after fly ash separation enters from the bottom of the wet scrubbing tower, is purified by water washing liquid sprayed through the pressure nozzles in the middle of the wet scrubbing tower, and the clean flue gas flows out through the flue gas outlet at the top of the wet scrubbing tower. The ash silo receives desulfurization ash from the semi-dry desulfurization tower and fly ash separated by the dust collector.

2. The treatment system for the concentration and reduction of waste incineration fly ash washing liquid and synergistic flue gas purification according to claim 1, characterized in that, A feedwater preheater is also installed between the buffer tank and the wet scrubbing tower. The feedwater preheater is connected to the economizer hot water to exchange heat with the washing liquid coming out of the buffer tank.

3. The treatment system for the concentration and reduction of waste incineration fly ash washing liquid and synergistic flue gas purification according to claim 1, characterized in that, The bottom slurry tank of the wet scrubbing tower is equipped with a conductivity meter and a level gauge; the demister at the top of the wet scrubbing tower is a wire mesh demister.

4. The treatment system for synergistic flue gas purification and concentration reduction of waste incineration fly ash washing liquid according to claim 1, characterized in that, The atomizer in the semi-dry desulfurization tower is a rotary atomizer.

5. The treatment system for synergistic flue gas purification and concentration reduction of waste incineration fly ash washing liquid according to claim 1, characterized in that, The spraying device has one or more sets of pressure nozzles; the solid-liquid separation device is one or a combination of a hydrocyclone, a centrifuge, or a vacuum filter.

6. A method for treating waste incineration fly ash washing liquid by concentration and volume reduction in synergistic flue gas purification based on the system described in any one of claims 1-5, characterized in that, The steps are as follows: The fly ash collected by the semi-dry desulfurization tower and dust collector is transferred to the ash storage silo. The fly ash in the ash silo is transferred to the washing tank. The fly ash is mixed with process water in the washing tank, and the agent is added and stirred for washing. The solid-liquid separator in the washing tank is used to separate the solid and liquid to obtain the impurity-removed and softened washing liquid and the desalinated fly ash. The washing liquid is transported to a buffer tank and then pumped to the slurry pool of the wet scrubbing tower via an inlet pump. The washing liquid is used as the spray liquid in the wet scrubbing tower and is pumped to the top of the wet scrubbing tower by a circulating pump and sprayed downwards. It comes into countercurrent contact with the low-temperature flue gas at the tail end, and the water in the washing liquid is evaporated by the waste heat of the flue gas, thereby achieving concentration and volume reduction. The concentration ratio is controlled by adjusting the flow rates of the inlet and outlet pumps and the circulating pump of the wet scrubbing tower, which promotes the saturation precipitation of chloride salts and solid-liquid separation. The concentrated washing liquid is transported to a semi-dry desulfurization tower, mixed with desulfurization slurry, and atomized into droplets by a rotary atomizer. The droplets come into contact with the high-temperature flue gas, where the water evaporates rapidly and the alkaline substances in the droplets react with the acidic gases in the flue gas. The solid product, desulfurization ash, after evaporation falls into the ash hopper and is then transferred and collected by a dust collector. The flue gas further enters the dust collector to remove fly ash, which enters the ash silo. The flue gas after dust removal enters the wet scrubbing tower, achieving zero wastewater discharge.

7. The processing method according to claim 6, characterized in that, The reagent is one or a combination of calcium hydroxide, sodium hydroxide, sodium carbonate, and sodium sulfide; the amount of reagent added is 5-10% of the fly ash mass.

8. The processing method according to claim 6, characterized in that, The atomizer operates at a speed of 10,000~15,000 rpm, and the liquid-to-gas ratio is 0.8~2.0 L / Nm³. 3 The droplet size is 50~250μm.

9. The processing method according to claim 6, characterized in that, The residence time of the flue gas in the wet scrubbing tower is 10-20 seconds, the droplet size range of the water washing liquid atomized by the pressure nozzle is 500-2000μm, and the total mass fraction of solids in the outlet concentrated alkali solution is 40%-60%.

10. The processing method according to claim 6, characterized in that, The concentrated washing liquid has a solid mass fraction of 20% to 45%; it is added to the desulfurization slurry as makeup water, and the total solid mass fraction in the desulfurization slurry after mixing is 15% to 25%.

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