Household garbage incineration fly ash washing dechlorination system and process

Abstract

The invention discloses a household garbage incineration fly ash washing dechlorination system and process. The system comprises a fly ash deep dechlorination reactor, and a dechlorination agent adding device, a stirring device, a micro-nano aeration device, an electrolysis device power supply and a temperature control device which are connected with the fly ash deep dechlorination reactor. The treatment process for remarkably reducing the chlorine content in the fly ash is provided according to the dechlorination treatment requirement of the waste incineration fly ash washing tail end, and remarkable convenient conditions are provided for wide resource utilization of the household waste incineration fly ash. The main innovation of the process is that the chlorine content in the waste incineration fly ash can be obviously reduced after four processes of breakpoint dechlorination, escape dechlorination, catalytic oxidation dechlorination and electrolytic dechlorination are carried out. After the fly ash is treated by the process, the chlorine content of the fly ash treated by the fly ash washing dechlorination process can be stably less than 0.1% and is far lower than the chlorine content of the fly ash washed by the waste incineration fly ash subjected to current countercurrent rinsing, and the process is stable in operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid waste resource utilization, and particularly relates to a system and process for washing and removing chlorine from municipal solid waste incineration fly ash. BACKGROUND

[0002] With the mainstream of municipal solid waste treatment gradually shifting from sanitary landfill to waste incineration, municipal solid waste incineration fly ash has become an important pollutant. Municipal solid waste incineration fly ash refers to the residual material collected in the flue gas purification system of a municipal solid waste incineration power plant, which contains organic pollutants such as benzene series and dioxins, as well as trace heavy metals such as Pb and Cr. According to the "Municipal Solid Waste Incineration Pollution Control Standard" (GB18485-2014), "municipal solid waste incineration fly ash shall be managed as hazardous waste". Therefore, fly ash must be collected separately and cannot be mixed with municipal solid waste, incineration residues, or other hazardous waste.

[0003] The high content components in fly ash include calcium chloride, calcium hydroxide, calcium sulfate, and calcium hydroxide. The traditional water washing process is to wash out the soluble chlorine ions, and then add heavy metal capture agents to remove heavy metal ions, calcium ion precipitants to precipitate calcium ions, and the decalcified solution is evaporated in an evaporator to obtain industrial-grade sodium chloride and potassium chloride. The above process is already quite mature. The water-washed fly ash is used in the next resource utilization.

[0004] Currently, the traditional water washing wastewater treatment has not significantly solved the problem of chlorine content in detoxified fly ash. From the perspective of the largest resource utilization market, detoxified fly ash needs to reduce the chlorine content to meet the raw material use of cement or concrete mixing stations, which must reduce the chlorine content to below 0.1%, or even below 0.06%, otherwise it may be suspected of dilution use. Currently, the chlorine content of the mainstream fly ash after detoxification is usually around 1%, which greatly limits the subsequent application scenarios of fly ash resource utilization and provides numerous obstacles for non-cement kiln resource utilization applications, affecting the great development of fly ash resource utilization.

[0005] Chinese invention patent CN202210930643.0 studies a preparation process for preparing high-purity calcium sulfate from waste incineration fly ash, which mainly uses sulfate to prepare high-purity calcium sulfate, saving operating costs and obtaining gypsum byproducts, but failing to further reduce the chlorine content in incineration fly ash.

[0006] Chinese invention patent CN202010890659.4 introduces a device and method for high-efficiency dechlorination of fly ash from waste incineration by reverse water washing of a grate furnace, which has a chlorine removal rate of more than 86% in the secondary countercurrent rinsing. According to the current chlorine content of more than 18% in the grate furnace, the chlorine content of the water-washed fly ash is still more than 1.5%, which fails to meet the set target of the present application.

[0007] Chinese invention patent CN201911142714.5 A kind of domestic waste incineration fly ash water washing dechlorination system and use method, by adding high concentration PAM in water washing separation process to carry out solid-liquid separation, and by multistage cyclone reactor to carry out solid-liquid separation, in the case of using three levels or multiple levels, the chlorine content of water washing fly ash can be reduced to about 0.5%, significantly reduce the chlorine content of fly ash in the current three-stage countercurrent rinsing process.The traditional water washing solid-liquid separation technology cannot further reduce the chlorine content in fly ash, which has a significant bottleneck.

[0008] Chinese invention patent CN201811549232.7 A kind of garbage incineration fly ash energy-saving dechlorination treatment process.The present application discloses an energy-saving treatment process for fly ash, which comprises fly ash washing, heavy metal removal, decolorization, calcium removal and evaporation crystallization steps, or comprises fly ash washing, heavy metal removal, decolorization and evaporation crystallization steps, the fly ash washing is multi-stage countercurrent washing, the water washing liquid of the last stage of multi-stage countercurrent washing is subjected to reverse osmosis membrane desalination treatment, the clean water produced by reverse osmosis membrane desalination treatment is reused as the water source for the last stage of washing, the concentrated water produced by reverse osmosis membrane desalination treatment is used as the water source for the previous stage of washing, the mass ratio of fly ash to water in the first stage of washing is controlled to be 1:1 to 1.1:1, solid-liquid separation is carried out after the first stage of washing, the solid is crushed and then enters the next stage of washing, and the liquid enters the heavy metal removal step.The present application has not been able to significantly reduce the chlorine content of water washing fly ash, and has not been able to find a method to reduce the chlorine content.

[0009] Chinese invention patent CN202210652918.9 A method for dechlorination of fly ash from domestic waste incineration.The present application discloses a method for dechlorination of fly ash from domestic waste incineration, which comprises the steps of mixing fly ash from domestic waste incineration with a specially prepared dechlorination agent to obtain a mixture, sintering the mixture to form dechlorination fly ash and chlorine-silicon gaseous substances, and then performing liquid-phase absorption on the tail gas to simultaneously achieve recovery of the dechlorination agent and generation of hydrochloric acid, which can be reused and resourced, respectively.

[0010] The present application uses high-temperature calcination method to volatilize chlorine ions at high temperature by taking advantage of their melting point, which is costly and the residual chlorine content is often above 0.3%.

[0011] Chinese invention patent CN202211226541.7 A garbage incineration fly ash rinsing process uses acid pickling to perform countercurrent rinsing on fly ash from domestic waste incineration, and even adds sulfuric acid to effectively volatilize chlorine ions during evaporation, but the chlorine content is not significantly reduced after countercurrent rinsing.

[0012] The above-mentioned various fly ash chlorine ion control technologies have not been able to reduce the chlorine content in detoxified fly ash to a level that can be widely resourced and utilized through suitable solid-liquid, liquid-gas phase conversion technologies, which greatly limits the widespread application of subsequent resource utilization of fly ash from waste incineration. SUMMARY

[0013] Therefore, the application provides a household garbage incineration fly ash water washing dechlorination system and process to solve the problems in the background art.

[0014] The application provides a household garbage incineration fly ash water washing dechlorination device, which comprises a fly ash deep dechlorination reactor, a dechlorination agent feeding device connected with the fly ash deep dechlorination reactor, a stirring device, a micro-nano aeration device, an electrolysis device power supply and a temperature control device; the electrolysis device power supply comprises an electrolysis anode and an electrolysis cathode; and the temperature control device is used for controlling the temperature in the reactor at 70-95 DEG C.

[0015] In an alternative embodiment, an ultraviolet light catalysis device is further included, and the ultraviolet light energy intensity of the ultraviolet light catalysis device is 0.8-1.2 kW / m 3 .

[0016] In an alternative embodiment, the dechlorination agent feeding device is configured to feed one or both of ammonia water and ammonium chloride, and the feeding concentration is 1000-50000 mg / L.

[0017] In an alternative embodiment, the stirring device is a triple stirrer, and the stirring intensity is greater than 15 W / (m 2 ·h).

[0018] In an alternative embodiment, the aeration intensity of the micro-nano aeration device is greater than 10 m 3 / (m 2 ·h).

[0019] In an alternative embodiment, the electrolysis device power supply adopts a direct current power supply, the current is 3-8 A, and the electrode adopts a graphene or graphite inert electrode.

[0020] A household garbage incineration fly ash water washing dechlorination process, characterized in that the process comprises the following steps:

[0021] S1. A three-stage countercurrent rinsing process is adopted to wash the household garbage incineration fly ash, so that the chlorine content of the fly ash is less than 1%;

[0022] S2. Without changing the water washing process flow and water-fly ash ratio, a deep dechlorination reaction is performed on the fly ash obtained in step S1, and the deep dechlorination reaction comprises adding a dechlorination agent to the fly ash, stirring, aeration and electrolysis treatment, and controlling the reaction temperature at 70-95 DEG C;

[0023] S3. Solid-liquid separation is performed to ensure that the water content after the solid-liquid separation is less than 35%, and the fly ash with a chlorine content less than 0.1% is obtained.

[0024] In an alternative embodiment, the step S2 further comprises an ultraviolet light catalytic treatment, and the ultraviolet light source of the ultraviolet light catalytic treatment has an intensity of 0.8 kW to 1.2 kW / m 3 And ferrous chloride is added as a catalyst, and the concentration is 500-1000 mg / L.

[0025] In an alternative embodiment, the dechlorinating agent is one or both of ammonia and ammonium chloride, and the addition concentration is 1000 mg / L to 50000 mg / L.

[0026] In an alternative embodiment, the stirring intensity is greater than 15 W / (m 2 ·h), and the aeration intensity is greater than 10 m 3 / (m 2 ·h);

[0027] And / or, the electrolytic treatment adopts a direct current power supply, the current is 3-8 A, and the electrode adopts a graphene or graphite inert electrode.

[0028] And / or, the deep dechlorination reaction in the step S2 is one or more stages.

[0029] The beneficial effects of the above technical solutions are:

[0030] The method of the application utilizes widely-sourced and stably-yielded domestic waste incineration fly ash washing wastewater for process development and research, and has broad spectrum.

[0031] The method of the application pursues high-efficiency treatment efficiency while not needing to change the existing running production line.

[0032] The process adopted by the application adopts four mechanisms of breakpoint dechlorination, fugitive dechlorination, catalytic oxidation dechlorination and electrolytic dechlorination for dechlorination, and is organically combined in one system, and finally removes liquid phase by converting chloride ions into gas phase, and main products include: chlorine, chlorine dioxide, ammonium chloride, hydrogen chloride ammonia, dichloro hydrogen ammonia, etc. The four dechlorination technologies can be used cooperatively, and two or several technologies can be selected for cooperative use according to the control requirements of the chlorine content.

[0033] The application realizes continuous feeding and continuous discharging throughout the whole process, and ensures stable operation of the whole process system.

[0034] The method of the application is simple to operate and has strong adaptability, and can be suitable for dechlorination treatment requirements of washing fly ash of different scales and different chlorine contents, and is supported by numerous practical applications.

[0035] The application utilizes post-washing fly ash from diversified resource utilization of waste incineration fly ash, and systematically proposes a method for solving problems, and provides a solution for fly ash resource utilization.

[0036] The application adopts a simple treatment process, maximally saves operation cost, and ensures that the chlorine content of the washed fly ash is less than 0.1% and a new solution is provided. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0038] Figure 1 It is a process schematic diagram of the high-efficiency domestic waste fly ash water washing dechlorination process of the present application.

[0039] Explanation of reference signs:

[0040] 1-chlorine removal agent adding device; 2-fly ash deep dechlorination reactor; 3-electrolytic anode; 4-electrolytic cathode; 5-micro-nano aeration device; 6-ultraviolet light catalysis device; 7-temperature control sensor; 8-vacuum extraction system; 9-stirring device; 10-aeration fan; 11-mixed liquid lifting pump; 12-electrolytic device power supply; 13-plate-frame filter press separator; 14-catalyst dosing system. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0042] In combination with Figure 1 As shown in the drawings, according to the embodiments of the present application, in the first aspect, a domestic waste incineration fly ash water washing dechlorination system and device are provided, which comprises a fly ash deep dechlorination reactor 2, and a chlorine removal agent adding device 1, a stirring device 9, a micro-nano aeration device 5, an electrolytic device power supply, a temperature control device, and a catalyst dosing system 14 connected with the fly ash deep dechlorination reactor. The temperature control device comprises a temperature control sensor 7, and the aeration device 5 comprises an aeration fan 10. The electrolytic device power supply 12 comprises an electrolytic anode 3 and an electrolytic cathode 4. The temperature control device is used for controlling the temperature in the reactor at 70-95℃. The fly ash deep dechlorination reactor 2 is further provided with a vacuum extraction system 8. The fly ash deep dechlorination reactor 2 is connected with a plate-frame filter press separator 13 through a pipeline, and a mixed liquid lifting pump 11 is arranged on the pipeline.

[0043] The domestic waste incineration fly ash water washing dechlorination system further comprises a UV light catalysis device 6, and the intensity of the UV light source of the UV light catalysis device is 0.8 kW-1.2 kW / m 3 .

[0044] The dechlorination agent adding device is configured to add one or both of ammonia water and ammonium chloride, and the adding concentration is 1000 mg / L-50000 mg / L.

[0045] The stirring device is a triple stirrer, and the stirring intensity is greater than 15 W / (m 2 ·h).

[0046] The aeration intensity of the micro-nano aeration device is greater than 10 m 3 / (m 2 ·h).

[0047] The power supply of the electrolysis device adopts a direct current power supply, the current is 3-8 A, and the electrode adopts a graphene or graphite inert electrode.

[0048] According to the embodiment of the present application, the second aspect provides a domestic waste incineration fly ash water washing dechlorination process, comprising the following steps:

[0049] S1. A three-stage countercurrent rinsing process is used to wash the domestic waste incineration fly ash, so that the chlorine content of the fly ash is less than 1%.

[0050] S2. Under the condition of not changing the water washing process and the water-fly ash ratio, the fly ash obtained in step S1 is subjected to a deep dechlorination reaction, the deep dechlorination reaction comprises adding a dechlorination agent to the fly ash, stirring, aeration and electrolysis treatment, and the reaction temperature is controlled to be 70-95 DEG C.

[0051] S3. Solid-liquid separation is performed to ensure that the water content after the solid-liquid separation is less than 35%, and the fly ash with a chlorine content of less than 0.1% is obtained.

[0052] The traditional three-stage countercurrent rinsing process is used in the water washing process of waste incineration fly ash to wash out calcium ions, chlorine ions, sodium ions, potassium ions, sulfate ions and the like in the fly ash, so as to ensure that the chlorine content of the water washed fly ash is less than 1%. Although the "Technical Code for Pollution Control of Domestic Waste Incineration Fly Ash (Trial)" (HJ 1134-2020) requires that the chlorine content of the pretreated fly ash be less than 2%. However, the biggest bottleneck for the subsequent resource utilization of the water washed fly ash is the chlorine content. From the perspective of fly ash building material resource utilization, too high chlorine content has a significant impact on furnace body corrosion, material safety, and legal and regulatory compliance. The traditional three-stage countercurrent rinsing process (with a water to fly ash ratio of less than 3:1) can only control the chlorine ions to about 1%. How to efficiently remove chlorine content from wastewater under the condition of conventional water to fly ash ratio is the main innovative value of this technology. The scheme realizes efficient reduction of chlorine content in fly ash through four processes of fold point dechlorination, escape dechlorination, catalytic oxidation dechlorination and electrolytic dechlorination.

[0053] As a preferred scheme, the system adds a fly ash deep dechlorination reaction section after the traditional three-stage countercurrent rinsing of fly ash, without changing the fly ash water washing process or increasing the water to fly ash ratio.

[0054] The step S2 also includes ultraviolet light catalytic treatment. The ultraviolet light energy intensity of the ultraviolet light catalytic treatment in the wastewater washing wastewater treatment process is 0.8kW~1.2kW / m 3 The ultraviolet light catalytic catalyst can use ferrous chloride, and the dosage concentration is 500~1000mg / L.

[0055] The dechlorination agent is one or both of ammonia water and ammonium chloride, and the dosage concentration is 1000mg / L~50000mg / L. The ammonia water is derived from production waste gas washing wastewater or byproduct ammonia water, so as to make it resourceful.

[0056] The stirring device uses a triple stirrer, and the stirring intensity is greater than 15W / (m 2 ·h), and the micro-nano aeration intensity is greater than 10m 3 / (m 2 ·h);

[0057] The electrolytic treatment uses a direct current power supply, and the current intensity is 3~8A. The electrode uses graphene or graphite inert electrode;

[0058] The deep dechlorination reaction in step S2 is one or more stages.

[0059] As a further improved embodiment, the present application adds a chlorine ion on-line detector, a pH sensor and an oxidation-reduction potential (ORP) sensor at the inlet and outlet of the fly ash deep dechlorination reactor to collect chlorine content and reaction environment parameters in real time. Based on the monitoring data, the PLC control system automatically adjusts the dosage of the dechlorination agent (ammonia water / ammonium chloride) (dynamically corrected according to the chlorine content deviation, with a precision of ±50 mg / L), the electrolytic current (self-adaptive adjustment within a range of 3-8 A, with a response time of less than 10 seconds), the stirring intensity and the aeration flow (real-time optimization according to the turbidity of the mixed liquid, with a stirring intensity fluctuation range of ≤±2 W / (m 2 ·h)). The problem of "over-treatment" or "under-treatment" caused by traditional fixed parameter processing is solved, the dechlorination efficiency is improved by 10%-15%, and the reagent consumption is reduced by 8%-12%.

[0060] As a further improved embodiment, the present application replaces the original single ammonia water / ammonium chloride dechlorination agent with a "ammonia water / ammonium chloride + industrial waste lye (such as calcium carbide slag supernatant)" composite system, with a molar ratio of 1:0.3-0.5. The gradient dosage strategy is to add the composite dechlorination agent in two stages in the deep dechlorination reaction section, with 60% of the total amount added in the first stage to achieve rapid breakpoint dechlorination, and the remaining 40% added in the second stage to cooperate with ultraviolet catalysis to enhance residual chlorine removal. The present application uses industrial waste lye to replace part of the ammonia water, reducing the reagent cost by 30%-40% and achieving waste treatment with waste; the composite system can increase the chlorine removal rate by 20%.

[0061] As a further improved embodiment, the present application uses a supported nano Fe3O4@TiO2 catalyst (particle size 50-100 nm) to replace traditional ferrous chloride, and realizes catalyst recovery (recovery rate ≥90%) through magnetic separation, with a recycling number of ≥30 times. A honeycomb type ultraviolet light reactor (ultraviolet wavelength 185-254 nm) is used, with a light path shortened to 1 / 3 of that of traditional devices, and a light utilization rate increased by 40%. The present application avoids the problem of residual iron ions caused by ferrous chloride, reduces the catalyst loss cost by 80%, and increases the ultraviolet light catalysis efficiency by 25%, with a reaction time shortened to 0.8 h.

[0062] As a further improved embodiment, the present application adds an "electrodialysis-nanofiltration" double membrane system after the original plate and frame pressure filtration: the chlorine-containing wastewater (Cl- concentration 5000-10000 mg / L) is concentrated to 20000-30000 mg / L, and the dilute water is reused to the water washing section (reuse rate ≥70%); the concentrated liquid is separated into NaCl and KCl (purity ≥98%) by nanofiltration, which is sold as industrial grade salt products. The water resource recycling rate of the present application is increased to more than 96%, and the operation cost per ton of water is reduced by 50 yuan; the by-product industrial salt can create additional economic benefits, offsetting 30% of the process cost.

[0063] As a further improved embodiment, the present application adds a vibrating screen (mesh 0.15mm / 0.075mm) before the three-stage countercurrent rinsing, separating coarse particles (>0.15mm), medium particles (0.075-0.15mm) and fine particles (<0.075mm). Coarse particles: directly into the deep dechlorination reactor (shortening the rinsing time by 50%); medium particles: conventional three-stage countercurrent rinsing; fine particles: using "ultrasonic-assisted water washing" (power 300W, frequency 40kHz), to enhance the dissolution of soluble chlorine. The present application differentiates the treatment of different particle sizes of fly ash according to the differences in chlorine occurrence characteristics, and the overall rinsing efficiency is improved by 15%-20%, and the water consumption is reduced by 12%.

[0064] As a further improved embodiment, the present application replaces the flat plate electrode with a "graphene-coated titanium-based three-dimensional electrode" (filling rate 30%-40%), which increases the specific surface area of the electrode to 500-800m 2 / m 3 . A pulse direct current power supply (frequency 500-1000Hz, duty cycle 30%-50%) is used to replace the traditional direct current power supply. The electrolysis efficiency is improved by 40%, the current density is reduced from 0.5A / dm 2 to 0.3A / dm 2 , the energy consumption is reduced by 35%-45%, and the electrode life is extended to more than 2 years (the service life of the traditional electrode is 6-8 months).

[0065] As a further improved embodiment, the present application adds a "condensation-absorption" double-tower system at the top of the reactor: first condensation: the escaped Cl2, HCl gas is cooled to 5-10℃ to form hydrochloric acid droplets; second absorption: absorbed by 10%-15% NaOH solution to generate sodium hypochlorite solution (available chlorine content ≥10%), which is recycled as a disinfection product or sold externally. Eliminate Cl2, HCl tail gas emission (removal rate ≥99%), while producing 200-500 tons of sodium hypochlorite per year.

[0066] Example 1

[0067] The waste incineration fly ash washing process employs a traditional three-stage countercurrent rinsing process. The original chlorine content of the fly ash is 18.8%. This process washes away calcium, chloride, sodium, potassium, and sulfate ions, etc., with a water-to-ash ratio of 2:1 (mass ratio). The chlorine content of the washed fly ash is less than 0.86%. After the three-stage washing and plate-and-frame filter press, the fly ash undergoes an additional dechlorination stage using this device. The residence time in this dechlorination device is controlled at 1 hour, and the ammonia concentration is 2000 mg / L. The stirring intensity is controlled at 15 W / (m²h), the aeration intensity at 10 m³ / (m²h), the electrolysis current at 5.5 A, the temperature at 85 degrees Celsius, the ultraviolet light intensity at 1 kW / m³, and the ferrous chloride dosage at 750 mg / L. After sufficient reaction, the fly ash is filtered using a plate-and-frame filter press. The moisture content of the filtered fly ash is 30%, and the chlorine content of the fly ash treated by this device is measured to be 0.08%.

[0068] Example 2

[0069] This study investigated the deep dechlorination treatment of fly ash from a company in a certain city. The original chlorine content of the fly ash was 20%, while the chlorine content of the washed fly ash was less than 1%. A second-stage dechlorination unit was added to the fly ash after the third-stage washing and plate-and-frame filter press. The residence time of this dechlorination unit was controlled at 1 hour, the ammonia dosage was 1000 mg / L, the stirring intensity was controlled at 15 W / (m²h), the aeration intensity was controlled at 12 m³ / (m²h), the electrolysis current was controlled at 3.5 A, the temperature was controlled at 85 degrees Celsius, the ultraviolet light energy intensity was 0.8 kW / m³, and the ferrous chloride dosage was 500 mg / L. After sufficient reaction, the fly ash was filtered using a plate-and-frame filter press. The moisture content of the filtered fly ash was 30%. The chlorine content of the first-stage fly ash after treatment was measured to be 0.3%, and the chlorine content of the second-stage fly ash was 0.09%.

[0070] Example 3

[0071] After a company in a certain city adopted this invention for its water-washed fly ash, the fly ash was subsequently used in cement kiln co-processing, and the fly ash addition amount increased from 1.5% to 3.5%, improving the economic efficiency of the fly ash production line and the cement kiln.

[0072] Example 4

[0073] This study focuses on deep dechlorination treatment of washed fly ash from a certain fly ash resource utilization production line. The original chlorine content of the fly ash was 19%, and the chlorine content of the washed fly ash was 0.82%. A second-stage dechlorination unit was added to the fly ash after the third-stage washing and plate-and-frame filter press. The residence time of this dechlorination unit was controlled at 1 hour, and the ammonia dosage was 2000 mg / L. The stirring intensity was controlled at 18 W / (m²h), the aeration intensity at 15 m³ / (m²h), the electrolysis current at 6 A, and the temperature at 85 degrees Celsius. Ultraviolet photocatalytic oxidation was not used. After sufficient reaction, the fly ash was filtered using a plate-and-frame filter press. The moisture content of the filtered fly ash was 30%. The chlorine content of the first-stage fly ash after treatment was measured to be 0.26%, and the chlorine content of the second-stage fly ash was 0.07%.

[0074] Example 5

[0075] After adopting this invention patent, a fly ash disposal unit in a certain province has increased the amount of fly ash added to more than 30% in the subsequent resource utilization process of water-washed fly ash in building materials, which was originally 15%, greatly enhancing the resource utilization value of detoxified fly ash.

[0076] Example 6

[0077] After adopting this invention patent, a fly ash disposal unit in a certain province was able to control the chlorine content of the washed fly ash to less than 0.06%, and then apply the dried washed fly ash to volcanic ash additives, admixtures, and concrete mixing plant mixes, greatly expanding the resource utilization pathways of washed fly ash.

[0078] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A device for washing and dechlorinating fly ash from municipal solid waste incineration, characterized in that, It includes a fly ash deep dechlorination reactor, and a dechlorination agent dosing device, a stirring device, a micro-nano aeration device, an electrolysis device power supply and a temperature control device connected to the fly ash deep dechlorination reactor; the electrolysis device power supply includes an electrolysis anode and an electrolysis cathode; the temperature control device is used to control the temperature inside the reactor at 70℃~95℃.

2. The municipal solid waste incineration fly ash washing and dechlorination device according to claim 1, characterized in that, It also includes an ultraviolet photocatalytic device, wherein the ultraviolet light energy intensity of the ultraviolet photocatalytic device is 0.8kW~1.2kW / m 3 .

3. The municipal solid waste incineration fly ash washing and dechlorination device according to claim 1, characterized in that, The dechlorination agent dosing device is configured to add one or both of ammonia water and ammonium chloride, with a dosing concentration of 1000 mg / L to 50000 mg / L.

4. The municipal solid waste incineration fly ash washing and dechlorination device according to claim 1, characterized in that, The stirring device is a triple stirrer with a stirring intensity greater than 15 W / (m²). 2 ·h).

5. The municipal solid waste incineration fly ash washing and dechlorination device according to claim 1, characterized in that, The aeration intensity of the micro-nano aeration device is greater than 10 m. 3 / (m 2 ·h).

6. The municipal solid waste incineration fly ash washing and dechlorination device according to claim 1, characterized in that, The electrolysis device is powered by a DC power supply with a current of 3-8A, and the electrodes are made of graphene or graphite inert electrodes.

7. A process for dechlorination of fly ash from municipal solid waste incineration by water washing, characterized in that, Includes the following steps: S1. A three-stage countercurrent rinsing process is used to wash the fly ash from municipal solid waste incineration, so that the chlorine content of the fly ash is less than 1%. S2. Without changing the water washing process and water-ash ratio, the fly ash obtained in step S1 is subjected to a deep dechlorination reaction. The deep dechlorination reaction includes adding a dechlorinating agent to the fly ash, stirring, aerating and electrolyzing, and controlling the reaction temperature at 70℃~95℃. S3. Solid-liquid separation, ensuring that the water content after solid-liquid separation is less than 35% and that the fly ash with a chlorine content of less than 0.1% is obtained.

8. The process for dechlorination of fly ash from municipal solid waste incineration according to claim 7, characterized in that, Step S2 further includes ultraviolet photocatalytic treatment, wherein the ultraviolet light energy intensity of the ultraviolet photocatalytic treatment is 0.8kW~1.2kW / m 3 Ferrous chloride was added as a catalyst at a concentration of 500–1000 mg / L.

9. The process for dechlorination of fly ash from municipal solid waste incineration according to claim 7, characterized in that, The dechlorinating agent is one or both of ammonia and ammonium chloride, with a dosage concentration of 1000 mg / L to 50000 mg / L.

10. The process for dechlorination of fly ash from municipal solid waste incineration according to any one of claims 7-9, characterized in that, The stirring intensity is greater than 15 W / (m 2 •h), aeration intensity greater than 10m 3 / (m 2 ·h); And / or, the electrolytic treatment uses a DC power supply with a current of 3-8A, and the electrodes are graphene or graphite inert electrodes; And / or, the deep dechlorination reaction in step S2 is one or more stages.

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