CN115889397B - Water washing dechlorination treatment process for household garbage incineration fly ash - Google Patents
Water washing dechlorination treatment process for household garbage incineration fly ash Download PDFInfo
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Abstract
The invention belongs to the technical field of catalysis, and particularly relates to a water-washing dechlorination treatment process of household garbage incineration fly ash. Comprises two working sections of water washing and water treatment; the washing section carries out secondary washing on the fly ash, and basically dissolves out and removes water-soluble components in the fly ash; the water treatment working section realizes the recycling recovery of chloride salt through purification and impurity removal, pH adjustment and MVR evaporation salt production treatment, basically recovers the water in the solution in a steam condensate water mode, and then sends the water to the water washing working section for recycling; and the exhaust steam evaporated by MVR is added with a proper amount of air and heated, and then the exhaust steam is subjected to catalytic hydrolysis-combustion treatment reactor, so that the enriched organic components including chlorine-containing organic components are basically converted into carbon dioxide and hydrogen chloride which is easy to absorb into solution, the water washing efficiency of the fly ash is improved, and the water consumption and the power consumption are obviously reduced. The process has higher operation efficiency, lower investment cost and operation cost and certain application prospect.
Description
Technical Field
The invention belongs to the technical field of catalysis, and particularly relates to a water-washing dechlorination treatment process of household garbage incineration fly ash.
Background
The fly ash is a powder material with lighter volume weight and small particle size which is collected at the positions of a flue gas purification system, a flue, the bottom of a chimney and the like in the incineration process of the household garbage, and contains dioxins chlorine-containing polycyclic aromatic hydrocarbon, cr, cd, hg, pb, cu, ni and other heavy metals. The fly ash production amount is about 3-5% of the garbage incineration amount. GB18485-2014 "pollution control Standard for household refuse incineration" specifies: "the fly ash of the incineration of the household garbage should be managed according to dangerous waste; if the waste is put into a household garbage landfill for disposal, the requirements of GB16889 are met; for instance, the cement kiln is used for treatment, and the requirements of GB30485 are met.
Fly ash contains NaCl, KCl, caClOH, caCl 2 Equal water-soluble salt and CaO and SiO which are relatively similar to cement clinker 2 、Al 2 O 3 And the like. Therefore, the fly ash can be used as an ingredient of silicate cement after being washed, the addition amount is about 5 percent of the yield of cement clinker, and the fly ash washing and cement kiln co-treatment technology is called in the industry. In recent years, the technology of the water washing of the fly ash and the cooperative treatment of the cement kiln is gradually applied and perfected, and the high Wen Duichong metal and dioxins of the cement kiln are utilized for solidification and decomposition, so that the advantages of high treatment capacity, high sewage containing capacity and high adaptability of the cement industry are brought into play, and good social benefits are obtained.
In the technology of fly ash washing and cement kiln co-treatment, the fly ash washing generally carries out multistage countercurrent rinsing, basically dissolves out water-soluble components such as potassium, sodium, chlorine and the like, then carries out solid-liquid separation, and the obtained filtrate is subjected to refining, MVR evaporation concentration crystallization to obtain byproducts such as sodium chloride, potassium chloride and the like; the filter cake obtained by solid-liquid separation, namely the water-washed fly ash, is generally controlled to have chlorine content less than or equal to 1.0 percent and water content less than or equal to 35 percent, and is sent to a cement kiln to be mixed with other cement raw materials and then calcined at high temperature. In the process of washing the fly ash, the water consumption and the electricity consumption of each ton of fly ash can reach the competitive economic index of 0.6 to 0.8 ton of water consumption and 110 to 130kWh of electricity consumption when the composition of the fly ash is normal and the washing process conditions are controlled to be proper.
Chinese patent CN109290345a discloses a fly ash treatment system and treatment device, in which a three-stage countercurrent flow is adopted in the washing section, and the fly ash filter cake is obtained by treating with a washing stirring tank and a horizontal decanter centrifuge and washing treatment. The ash washing wastewater treatment unit adopts a combined process of sodium carbonate decalcification, water quality stabilization, hydrochloric acid neutralization, precise filtration and MVR evaporative crystallization.
Chinese patent CN113231446a discloses a treatment and disposal system for incineration fly ash of household garbage, comprising a three-stage gradient water washing subsystem, a filtrate post-treatment subsystem, an MVR evaporation salt-making subsystem, a filter pressing subsystem and a filter cake post-treatment subsystem. The three-stage gradient water washing subsystem comprises three gradient stirring water washing reaction tanks and three-stage sedimentation tanks, wherein the stirring water washing reaction tanks are in countercurrent flow of the whole materials/liquid, and a discharge hole of each gradient stirring water washing reaction tank is connected with a feed inlet of the same-stage sedimentation tank; the filtrate and the filter cake of the upper two-stage sedimentation tank are respectively introduced into a next-stage stirring water-washing reaction tank; the residual filtrate of the lower two-stage sedimentation tank and the make-up water are respectively returned to the upper-stage sedimentation tank after being mixed; the filtrate and the filter cake treated by the three-stage gradient water washing subsystem are respectively introduced into a filtrate post-treatment subsystem and a filter pressing subsystem; adding process water with the water-cement ratio of 10:1 into the stirring water-washing reaction tank; the filtrate aftertreatment subsystem comprises an inorganic membrane filtration reaction tank, an alkali-adjusting reaction tank, a heavy metal removal reaction tank and a hardening-adjusting reaction tank which are connected in sequence; an inorganic ceramic membrane with the aperture less than or equal to 100nm is arranged in the inorganic membrane filtration reaction tank and is used for filtering filtrate; introducing an acidic solution into the alkali regulating reaction tank, and regulating the pH value of the filtrate to be neutral; adding a specially prepared heavy metal directional adsorption material such as organic covalent framework material COFs into the heavy metal adsorption reaction tank; an alkaline solution is introduced into the hardening reaction tank; introducing filtrate treated by the hardening reaction tank into an MVR evaporation salt making subsystem for evaporation salt making; and the filter pressing subsystem is used for filtering the filter cake and then sending the filter cake to the filter cake post-treatment subsystem for treatment. The filter cake post-treatment subsystem comprises a high-temperature sintering system, a high-temperature gasification/plasma melting system, a cement kiln co-treatment system or a solidification/stabilization treatment system.
Chinese patent CN109956690a discloses a method for treating fly ash from incineration of household garbage in cement industry, comprising the following steps: step one, ultrasonic and additive water washing fly ash dechlorination adsorption heavy metal: incineration fly ash, porous additives capable of heavy metal adsorption such as bentonite and water are mixed according to the following ratio of 100: (0.5-5): (200-400) and mixing in ultrasonic washing equipment to form water-ash mixed liquor, simultaneously stirring for 10-30 min to wash, and the ultrasonic power density is preferably 0.2-0.8 w/cm 3 Transferring the water-ash mixed solution to dehydration equipment after water washing; step two: the water-ash mixed solution is carried out by centrifugal equipmentThe content of heavy metal in the dehydrated filtrate is low, and the different chloride and reuse water can be obtained by means of multi-effect evaporation and the like without additional heavy metal removal treatment, and a filter cake with the water content lower than 35% is sent to a cement kiln for cooperative treatment.
In the prior art, the dechlorination rate of the filter cake from fly ash to water-washed fly ash, namely, the water content is lower than 35%, and the dechlorination rate can reach 95% and 99% in some cases, but the dechlorination rate is obtained under the condition of adopting lower water-washed slurry concentration or adopting power ultrasound, and the dechlorination rate is not competitive in the aspects of economy in the complete technology of the co-treatment of fly ash water washing and a cement kiln; when the concentration of the water washing slurry is low and the circulation amount of the washing water is too large, the condensation water amount of multi-effect evaporation such as MVR is high, and the running cost and the investment of the device are high; 0.2-0.8 w/cm 3 The ultrasonic power density, equipment investment and operation cost are also higher. Even if the equipment configuration and the process operation conditions are relaxed, such as the use of lower water-ash ratio water-washing slurry, i.e. the use of higher concentration water-washing slurry, and the use of lower power ultrasound or shorter ultrasound treatment time, the water-washing fly ash is difficult to realize as the technical index of cement kiln ingredients, i.e. the chlorine content is less than or equal to 1.0%, preferably less than or equal to 0.6%, the water content is less than or equal to 35%, preferably less than or equal to 30%, and the economic index of water consumption of less than or equal to 0.6 tons and electricity consumption of less than or equal to 110kWh for treating each ton of fly ash. Even if the technical index and the economic index can be realized, the method is often obtained under the condition that the fly ash is easy to treat or has narrow operation elasticity, so the competitiveness in the complete technology of the fly ash washing and the cement kiln collaborative treatment is still low. Although the application of the power ultrasound in the environment-friendly and energy fields has a certain foundation, the efficiency and cost ratio of an ultrasonic system, namely the reliability and the unit power cost, are still insufficient in the fly ash water washing treatment; and the ultrasonic treatment can cause remarkable refinement and expansion of fly ash in the slurry, the filtering difficulty is high, and the water content of a filter cake is not easy to control to be less than or equal to 35 percent.
Therefore, there is a need to develop a water-washing and dechlorination treatment process for household garbage incineration fly ash, which can more easily obtain the technical index and economic index of water-washing fly ash as cement kiln ingredients under the condition of wider operation elasticity, and has higher competitiveness in the complete technology of the cooperative treatment of fly ash water washing and cement kiln.
Disclosure of Invention
In order to solve the technical problems, the invention provides a water-washing dechlorination treatment process of the household garbage incineration fly ash, which can obviously reduce the concentration of chlorine-containing organic components in the fly ash.
The water-washing and dechlorination treatment process of the household garbage incineration fly ash comprises a fly ash water-washing working section and a water treatment working section; the fly ash washing working section comprises two stages of washing, and the washing water comprises fresh water and MVR steam condensate water; the water treatment working section comprises a purifying and impurity removing working procedure, a pH adjusting working procedure and an MVR evaporation salt making working procedure, and MVR steam condensate water in the MVR evaporation salt making working procedure is sent back to the fly ash washing working section for recycling; the method is characterized in that exhaust steam accounting for 1-3% of the steam flow of MVR is discharged from an MVR evaporator in an MVR evaporation salt making process, 8-15v% of air is added, the temperature of a catalyst bed is controlled to 300-330 ℃ through a catalytic hydrolysis-combustion treatment reactor, organic components enriched in the exhaust steam comprise chlorine-containing organic components and are converted into carbon dioxide and hydrogen chloride, and outlet steam is mixed with impurity-containing mother liquor after MVR evaporation crystallization and then sent to a purification and impurity removal process for absorption and treatment;
the catalytic hydrolysis-combustion treatment reactor is filled with a hydrolysis-combustion treatment catalyst, and the hydrolysis-combustion treatment catalyst comprises the following components: 8-10wt% of FeO; mnO 3-5wt%; ceO (CeO) 2 1.5-3wt%；WO 3 1-2wt%; the balance being TiO 2 。
Wherein:
the preparation method of the hydrolysis-combustion treatment catalyst comprises the following steps:
(1) Roasting the meta-titanic acid powder to obtain titanium dioxide powder;
(2) Preparing a mixed aqueous solution of ferrous acetate, manganese acetate and cerium acetate, adding the titanium dioxide powder obtained in the step (1), pulping, granulating the obtained slurry by hot air spraying at 280-320 ℃, and cooling to room temperature to obtain granulated powder;
(3) And (3) atomizing and spraying an ammonium tungstate solution on the granulated powder obtained in the step (2), discharging, sealing, homogenizing at room temperature, drying, making into tablets, and roasting to obtain the hydrolysis-combustion treatment catalyst.
Step (1) of the meta-titanic acid powder material by H 2 SO 4 The sulfur content is less than or equal to 0.3 weight percent, the roasting temperature is 400-420 ℃, and the roasting time is 2-4 hours.
In the step (2), the weight ratio of the mixed aqueous solution to the titanium dioxide powder obtained in the step (1) is 3-4:1; the average grain diameter of the granulated powder is 100-200 mu m.
In the step (3), the volume of the ammonium tungstate solution is 43-46% of the saturated water absorption volume of the granulated powder.
In the step (3), the homogenization treatment time is 10-20h.
In the step (3), the roasting temperature is 400-430 ℃ and the roasting time is 2-3h.
The process of preparing tablets in step (3) is carried out in a tablet press, and tablets with the diameter of 4-6x3-5mm are prepared.
The fly ash washing section adopts a water-ash ratio of 3-3.5.
In the fly ash washing section, a first-stage premixing machine mixes fly ash and washing liquid of a first-stage spiral filter to form slurry, the slurry is circularly washed in a first-stage washing tank, sodium carbonate solution is injected into the first-stage washing tank to generate calcium carbonate for removing calcium, and then the calcium carbonate is filtered and washed by the first-stage spiral filter to obtain first-stage filtrate, a first-stage filter cake and washing liquid of the first-stage spiral filter, and the first-stage filtrate is collected and sent to a purifying and impurity-removing step of the water treatment section; the second-stage premixing machine mixes the first-stage filter cake and the washing liquid of the second-stage spiral filter to form slurry, the slurry is circularly washed in a second-stage washing tank, and then the slurry is filtered and washed by the second-stage spiral filter to obtain second-stage filtrate, a second-stage filter cake and the washing liquid of the second-stage spiral filter, and the second-stage filtrate is returned to the first-stage spiral filter to be used as the washing liquid in a circulating manner;
in the water treatment section, the primary filtrate enters a purifying and impurity removing step for purifying and impurity removing, then enters a pH adjusting step for adjusting the pH value, and then enters an MVR evaporation salt making step; MVR steam condensate water and fresh water in the MVR evaporation salt making process enter a secondary spiral filter for recycling, and salt obtained after MVR evaporation crystallization enters a chloride storage tank.
The average residence time of the slurry in the primary water washing tank and the secondary water washing tank is 1-2h.
In the invention, the following components are added:
the hydrolysis-combustion treatment catalyst has stable catalytic reaction activity, and shows higher hydrolysis dechlorination and catalytic combustion performances on chlorine-containing organic matters such as chlorine-containing polycyclic aromatic ring organic matters and higher catalytic combustion performances on organic matters such as polycyclic aromatic ring organic matters under the condition of high steam content, and basically converts carbon dioxide and hydrogen chloride which is easy to be absorbed into solution; the catalyst has high mechanical strength, axial and radial compressive strength not less than 160N/particle, and after long-period reaction, the catalyst can keep stable particles, no adhesion and no pulverization.
The fly ash contains organic components, which are typically chlorine-containing organic substances such as chlorine-containing polycyclic aromatic ring organic substances, and organic substances such as polycyclic aromatic ring organic substances are also present. The invention discovers that in the operation process of the fly ash washing working section, the organic components contained in the fly ash comprise chlorine-containing organic components, a part of the organic components enter primary filtrate, namely a chloride salt solution, and a part of the organic components in the chloride salt solution enter steam in the MVR evaporation process and are enriched in the exhaust steam position after the steam is heated and condensed. The invention further discovers that the exhausted steam after the MVR evaporator steam heat supply condensation is led out at a certain flow, the content of organic components including chlorine-containing organic components in MVR steam condensate water can be obviously reduced, and the content of organic matters in slurry is obviously reduced after the condensate water is sent back to the fly ash washing section for recycling.
The catalytic hydrolysis-combustion treatment reactor is adopted to treat the exhaust steam, so that the content of organic components including chlorine-containing organic components in condensed water after MVR steam heat supply is obviously reduced. After the condensed water is sent back to the fly ash washing working section for recycling, the organic matter content in the slurry is also obviously reduced, the surface property of the powder particles in the slurry is changed, the dissolution rate of water-soluble components in the fly ash is further obviously improved, the slurry is easy to settle and filter, the water content of a filter cake is also obviously reduced, and therefore the washing treatment efficiency of the fly ash is improved.
The water washing working section is easy to achieve the technical indexes of chlorine content of the water washing fly ash of less than or equal to 0.6 percent and water content of less than or equal to 30 percent after adopting a lower water ash ratio of 3 to 3.5, and the economic indexes of water consumption of less than or equal to 0.6 ton and power consumption of less than or equal to 110kWh (basically adopting no other heat source) and the like of each ton of fly ash treatment, wherein the lower water ash ratio of 3 to 3.5 is the basic precondition of the power consumption of less than or equal to 110kWh of each ton of fly ash treatment, and the water content of the water washing fly ash of less than or equal to 30 percent is the important precondition of the water consumption of less than or equal to 0.6 ton of each ton of fly ash treatment; and after the outlet steam is mixed with the impurity-containing mother liquor after MVR evaporation and crystallization, the impurity-containing mother liquor is continuously conveyed to the impurity-removing and purifying process in a liquid-gas inclusion mode by utilizing the pressure of residual air flow, and the heat of the outlet steam after the exhaust steam treatment is utilized, so that the impurity-containing mother liquor after MVR evaporation and crystallization is not easy to crystallize and block in a pipeline for conveying the impurity-removing and purifying process. The outlet steam flow rate after the catalytic hydrolysis-combustion treatment reactor is smaller, wherein the carbon dioxide content is less than or equal to 10000ppmv, the hydrogen chloride content is less than or equal to 2000ppmv, and the catalytic hydrolysis-combustion treatment reactor has certain pressure; the discharge flow rate of the outlet steam is controlled through a valve, so that the content level of carbon dioxide and hydrogen chloride in the outlet steam of the catalytic hydrolysis-combustion treatment reactor and the content level of organic components including chlorine-containing organic components in the MVR steam, condensed water and water treatment working section solution can be controlled. The generation of organic matters in fly ash including chlorine-containing organic components is unavoidable in the operation of a household garbage incinerator; because of the low content, the prior art generally does not pay attention to the influence of the chlorine-containing polycyclic aromatic hydrocarbon on the water washing process, but only pays attention to the toxicity of trace components such as dioxins, chlorine-containing polycyclic aromatic hydrocarbon and the like, but the organic matters comprise the chlorine-containing organic components which are the intermediates of the toxicity such as dioxins, chlorine-containing polycyclic aromatic hydrocarbon and the like, and the content of the organic matters is much higher.
In the water-washing dechlorination treatment process of the household garbage incineration fly ash, two-stage water washing of a fly ash water washing working section is realized by a premixing machine, a water washing tank with slurry circulation and a spiral filter with continuous water washing function which are sequentially connected. The spiral filter is a horizontal spiral filter centrifuge.
In the fly ash washing working section, a first-stage premixing machine mixes fly ash and washing liquid of a first-stage spiral filter to form slurry, the slurry is circularly washed in a first-stage washing tank, sodium carbonate solution is injected into the first-stage washing tank to generate calcium carbonate for removing calcium, and then the calcium carbonate is filtered and washed by the first-stage spiral filter to obtain first-stage filtrate, a first-stage filter cake and the washing liquid of the first-stage spiral filter, and the first-stage filtrate is collected and sent to a purifying and impurity removing working section; the second-stage premixing machine mixes the first-stage filter cake and the washing liquid of the second-stage spiral filter to form slurry, the slurry is circularly washed in a second-stage washing tank, and then the slurry is filtered and washed by the second-stage spiral filter to obtain second-stage filtrate, a second-stage filter cake and the washing liquid of the second-stage spiral filter, and the second-stage filtrate is returned to the first-stage spiral filter to be used as the washing liquid in a circulating manner; the second filter cake is the water-washed fly ash. The average residence time of the slurry in the primary water washing tank and the secondary water washing tank is 1-2h.
The spiral filter with the continuous washing function is prepared from commercial equipment, and the main structure and the working principle are as follows: the core component is a rotary drum and an outer spiral, and chemical fiber filter cloth and/or a metal filter screen are arranged outside the outer spiral; the rotary drum and the external spiral rotate at a certain differential speed in the same direction and high speed, the slurry and the washing liquid are respectively and continuously introduced from the respective feeding pipes, enter the rotary drum at different positions after being accelerated respectively, and solid phase matters are deposited on the wall of the rotary drum to form a slag layer under the action of a centrifugal force field, and the washing is completed while the filtering is carried out; the deposited solid phase matters are continuously pushed to the cone end of the rotary drum by the external screw, discharged out of the machine through a slag discharge port, and filtrate and washing liquid are respectively collected and simultaneously flow out; the centrifugal machine can continuously feed, separate, wash and discharge materials under full-speed operation, and has the characteristics of compact structure, continuous operation, stable operation, strong adaptability, large production capacity, convenient maintenance and the like. The power consumption is low, and the filtering rate and the washing effect are obviously better than those of the traditional centrifugal filtering equipment. In the prior art, the fly ash washing working section generally adopts a higher water-ash ratio of 4-6, the fly ash in the slurry has higher puffing rate and slower sedimentation, each stage of separation often needs to adopt a horizontal spiral sedimentation centrifuge without continuous washing function and a horizontal spiral filtering centrifuge without continuous washing function for combined use, and three stages of washing generally need to be adopted. In the invention, the fly ash washing working section is arranged, so that the two-stage washing achieves or exceeds the effect of three-stage washing in the prior art; and then the exhaust steam combined with MVR steam is treated by a catalytic hydrolysis-combustion treatment reactor, and after the concentration of the organic components including chlorine-containing organic components in the recycled MVR condensate water is obviously reduced, the fly ash washing section can treat the fly ash with complex components under the condition of wider operation elasticity.
The MVR is a vapor mechanical recompression technology, which is used for mechanically recompressing secondary vapor flow generated during the indirect evaporation and concentration of the aqueous solution, improving the temperature and pressure of the vapor, increasing the enthalpy of the vapor, and then using the vapor as a heat source for the indirect evaporation and concentration of the aqueous solution, so that the water in the solution is evaporated to become condensed water, thereby fully utilizing the latent heat of the vapor. The first-stage filtrate, namely the chloride solution, can reach the theoretical ten-effect evaporation energy-saving level in the concentration process; in addition to the starting stage, no steam is needed to be added in the evaporation process of the MVR evaporation salt making process, so that the requirement and consumption of external energy sources are reduced.
In the water-washing dechlorination treatment process of the household garbage incineration fly ash, the purification and impurity removal procedure, the pH adjustment procedure and the MVR evaporation salt production procedure of the water treatment procedure are adopted, and conventional operation procedures and equipment are adopted, wherein the purification and impurity removal comprises precipitation, filtration and deslagging and tubular microfiltration, and filter residues are sent to a water-washing fly ash stock base for blending after water washing; the pH is adjusted by adding hydrochloric acid into the solution for neutralization; after MVR is evaporated, chloride salt, such as sodium chloride/potassium chloride mixed salt or potassium chloride, which meets the index requirement of washing chloride of fly ash treatment products is co-processed in a cement kiln of China cement society group standard T/CCAS 010-2019 by controlling the crystallization conditions of quality division; a small amount of mother liquor containing impurities after MVR evaporation and crystallization can be sent back to the purification and impurity removal process for recycling.
The invention relates to a water washing and dechlorination treatment process of household garbage incineration fly ash, which is mainly characterized in that a catalytic hydrolysis-combustion treatment reactor and a static mixer are added, a proper amount of air with the concentration of about 8-15v% is matched through the static mixer, air-containing dead steam at the outlet of the catalytic hydrolysis-combustion treatment reactor, namely outlet steam, can be blown into impurity-containing mother liquor after MVR evaporation crystallization, and the residual air flow pressure is utilized to continuously convey the impurity-removing liquid to a purification and impurity-removing process at the temperature of 70-90 ℃ for further absorption treatment and impurity removal and utilization of the crystallization mother liquor.
Compared with the prior art, the invention has the following advantages:
(1) The concentration of the organic components in MVR steam, condensed water, slurry and fly ash including chlorine-containing organic components can be obviously reduced by leading out the exhaust steam flow of MVR steam, adding air and heating and then processing the exhaust steam flow in a catalytic hydrolysis-combustion processing reactor, and basically converting the enriched organic components including the chlorine-containing organic components into carbon dioxide and hydrogen chloride which is easy to absorb. After the condensed water is sent back to the fly ash washing working section for recycling, the dissolution rate of water-soluble components in the fly ash is obviously improved, slurry is easy to settle and filter, and the water content of a filter cake is obviously reduced, so that the washing treatment efficiency of the fly ash is improved to a certain extent. The washing working section can adopt a lower water-ash ratio of 3-3.5, a flocculating agent is not needed, a sedimentation tank is not needed, the flow is simplified, and the operation and control are reliable.
(2) The method is easy to achieve the technical indexes of chlorine content less than or equal to 0.6 percent and water content less than or equal to 30 percent of the washing fly ash, and the economic indexes of water consumption less than or equal to 0.6 ton, power consumption less than or equal to 110kWh and the like of each ton of fly ash treatment; and the investment cost and the running cost of the device are low.
(3) The waste liquid and the waste residue do not exist, the exhaust gas meets the index requirements of the emission standard of GB31573-2015 inorganic chemical industry pollutants, the exhaust steam containing more organic components including chlorine-containing organic components is subjected to continuous catalytic hydrolysis-combustion and is sent to the purification and impurity removal process for absorption treatment, pollution and peculiar smell are basically eliminated, other dry fly ash, water-washed fly ash and slurry are stored and treated in a closed and negative pressure factory building, and the exhaust gas is discharged up to the standard after concentrated treatment.
(4) The method is easy to be used for the expansion transformation of the existing fly ash washing treatment device, and has higher competitiveness in the complete technology of the fly ash washing and cement kiln collaborative treatment.
In conclusion, the water washing working section mainly carries out secondary water washing on raw material fly ash, and basically dissolves out and removes water-soluble components such as potassium, sodium, chlorine and the like in the fly ash; the water treatment working section realizes the recycling recovery of chloride salt through the treatments of purifying and removing impurities, regulating pH, MVR evaporating salt production and the like, and realizes the basic recovery of water in the solution in a steam condensate mode and the recycling of the water returned to the fly ash washing working section; the exhaust steam of the MVR evaporator is matched with a proper amount of air to be heated, and then the exhaust steam is subjected to catalytic hydrolysis-combustion treatment reactor, so that the enriched organic components including chlorine-containing organic components are basically converted into carbon dioxide and hydrogen chloride which is easy to absorb into solution, thereby obviously reducing the concentration of the MVR steam, MVR steam condensate water, slurry and organic components including the chlorine-containing organic components in the fly ash, improving the dissolution rate of water-soluble components in the fly ash to a certain extent, reducing the water content of a filter cake to a certain extent, improving the washing efficiency of the fly ash, and enabling the washing section of the fly ash to adopt a lower water-ash ratio. The invention has the advantages of obviously reduced water consumption and power consumption, higher operation efficiency, lower investment cost and operation cost, and certain application prospect.
Drawings
Fig. 1 is a schematic flow chart of the water-washing dechlorination treatment process of the household garbage incineration fly ash of example 1.
Detailed Description
The technical scheme of the present invention is further described and illustrated below with reference to examples.
Example 1
The catalyst of this example was prepared in cooperation with the catalyst manufacturer as follows:
(1) With TiO 2 Taking 5.2kg of metatitanic acid powder material based on dry basis, and taking H as a raw material 2 SO 4 The sulfur content is 0.21wt percent, and the titanium dioxide powder is obtained by roasting for 2 hours at 420 ℃ under the conditions of a muffle furnace and air;
(2) Preparing 3200g of mixed aqueous solution of ferrous acetate, manganese acetate and cerium acetate with required concentration in a stirring reaction tank, adding 1000g of titanium dioxide powder in the step (1) into the mixed aqueous solution, pulping for 30min, granulating the obtained slurry by hot air spraying at 300 ℃, and cooling to room temperature to obtain granulated powder; the saturated water absorption volume is measured to be 0.46ml/g;
(3) And (3) putting 1000g of the granulated powder obtained in the step (2) into a rotary drum, atomizing and spraying 210ml of ammonium tungstate solution with the required concentration, discharging, bagging, sealing, homogenizing at room temperature for 15h, drying at 110 ℃ for 5h, preparing the dried powder into tablets with phi 4x5mm by a tablet press, and roasting at 410 ℃ for 3h under muffle furnace and air conditions to obtain the catalyst.
In the preparation process, the mixed aqueous solution of the ferrous acetate, the manganese acetate and the cerium acetateThe concentration of the ammonium tungstate solution is calculated by weight percent in the catalyst, and the concentration comprises FeO 9%, mnO 4% and CeO 2 2%，WO 3 1.5% and the balance of TiO 2 And (5) preparing. The axial compressive strength and the radial compressive strength of the catalyst are respectively 20, the average values are 305N/particle and 261N/particle, and the mechanical strength is high.
The catalyst application process is as follows:
the total content of chlorine-containing organic matters and chlorine-free organic matters of more than six carbons in the related materials, liquid and vapor was measured for a plurality of times on the existing 50000t/a fly ash water washing and dechlorination treatment device, and typical values are shown in Table 1 in terms of C, cl.
TABLE 1 content conditions
As can be seen from Table 1, the organic components contained in the fly ash include chlorine-containing organic components, and a part of the organic components enter the primary filtrate, namely, the chloride salt solution; most of the organic components in the chloride solution comprise chlorine-containing organic components, steam enters in the MVR evaporation process, but enters MVR steam condensate water after the steam supplies heat, and the exhaust steam position is enriched during the steam supply, namely the organic components entering the chloride solution comprise chlorine-containing organic components which are recycled along with the MVR steam condensate water, and the organic components accumulate in the system to a certain extent.
The existing 50000t/a fly ash water washing and dechlorination treatment device comprises two working sections of fly ash water washing and water treatment; the fly ash washing working section comprises three-stage washing, and the washing water comprises fresh water and MVR steam condensate water; the water treatment working section comprises a purifying and impurity removing working procedure, a pH adjusting working procedure and an MVR evaporation salt making working procedure, wherein condensed water is sent back to the fly ash washing working section for recycling after MVR steam in the MVR evaporation salt making working procedure supplies heat. The relevant main indexes comprise: the water washing working section adopts the water-ash ratio of 4.5, the chlorine content of the water washing fly ash is 0.9-1.0%, the water content is 33-35%, the water consumption of each ton of fly ash treatment is 0.65 ton, and the power consumption is 130kWh (basically no other heat source is adopted). The process operation elasticity of the device is general, the byproduct chloride salt is mixed salt of sodium chloride and potassium chloride, and sometimes the index requirement of the product water washing chloride of the co-processed fly ash of the cement kiln of China cement society group standard T/CCAS 010-2019 is not met.
And carrying out a lead-out test of exhaust steam after the MVR evaporator steam is subjected to heat supply and condensation. The exhaust steam was fed at about 800Nm 3 The flow of/h is led out and discharged, other conditions are unchanged, MVR steam condensate water is detected in 40h operation after 20h stabilization, the total content of more than six chlorine-containing organic matters and more than six chlorine-free organic matters of the primary filtrate, namely the chloride salt solution before purification and impurity removal, can be reduced by about 90%, the chlorine content of the produced water washing fly ash is reduced to 0.7-0.8%, the water content is reduced to 30-32%, and the sedimentation and filtration rate of the fly ash water washing slurry are obviously improved. Therefore, after the exhaust steam of the MVR evaporator is led out at the flow, the content of the MVR condensate water and the organic components in the fly ash water-washing slurry, including the chlorine-containing organic components, can be obviously reduced, the dissolution rate of the water-soluble components in the fly ash is improved, the water content of a filter cake is obviously reduced, and the water-washing treatment efficiency of the fly ash is improved.
The catalyst manufacturer enlarges and produces the catalyst, 25L is sampled from the catalyst, and 600h treatment test of lateral line MVR evaporation dead steam is carried out in the 50000t/a fly ash water washing and dechlorination treatment device. Specifically, steam at the upper position of condensate water of an MVR evaporator is led out as exhaust steam, 12v percent of air is matched in through a static mixer, and the air flow airspeed is controlled for 500h through a catalyst bed with the temperature of 315-330 DEG C -1 . The test results include: the HCl generation rate of chlorine contained in the organic component in the gas stream is always kept at 95-96%, and CO containing carbon is obtained 2 The production rate is kept at 87-89% all the time, and the production rate does not decrease. After the test is finished, the catalyst is discharged, and the catalyst is easy to discharge, has no pulverization and no adhesion; chlorine content was measured at only 2.5mg/g. The axial compressive strength and the radial compressive strength of the discharged catalyst were measured to be 20 particles each, and the average values were 308N/particle and 255N/particle, respectively, and it was considered that the mechanical strength was not lowered.
After the 600h treatment test of the side MVR evaporation dead steam is finished, filling the 2.0m of the side MVR evaporator of the 50000t/a fly ash water washing and dechlorination treatment device 3 Catalytic hydrolysis-combustion treatment reactor for catalyst, reactor outletThe outlet steam is introduced into the mother liquor containing impurities after MVR evaporation and crystallization. Specific control conditions include: the temperature of the catalyst bed layer in the reactor is 315-330 ℃, and the exhaust steam flow is controlled to be 800Nm respectively 3 /h (about 2% of MVR vapor flow rate), 400Nm 3 /h (about 1% of MVR vapor flow rate), 1000Nm 3 Per h (3% of MVR steam flow), 80Nm were added by means of static mixers 3 /h、60Nm 3 /h、80Nm 3 Air/h. In the operation process of about half a year, the total content of more than six chlorine-containing organic matters and the total content of more than six chlorine-free organic matters in the primary filtrate, namely the chloride salt solution, before the MVR steam condensate water and the purification and impurity removal are detected for many times, the total content of more than six chlorine-containing organic matters and the total content of more than six chlorine-free organic matters can be reduced by 85-90%, the chlorine content of the produced water washing fly ash is reduced to 0.7-0.8%, the water content is reduced to 30-32%, the sedimentation and filtration rate of the fly ash water washing slurry are obviously improved, and the fly ash dechlorination treatment effect of the exhaust steam after the MVR evaporator steam is heated and condensed is led out and discharged at the same flow rate and is stably operated for 40 hours can be basically achieved. After the air-containing exhaust steam at the outlet of the catalytic hydrolysis-combustion treatment reactor is introduced into the impurity-containing mother liquor after MVR evaporation crystallization, the liquid-gas inclusion temperature is 70-90 ℃ and the pH value is 4-5, and the liquid-gas inclusion temperature is continuously pushed into the chloride salt solution before impurity removal and purification by the pressure of the residual air, so that further absorption treatment and impurity removal and utilization of the crystallization mother liquor are carried out.
On the basis of adding a catalytic hydrolysis-combustion treatment reactor to the 50000t/a fly ash water washing and dechlorination treatment device, the overhaul shutdown is utilized to partially reform the fly ash water washing section. The main flow of the section after transformation is shown as a figure 1, and comprises a two-stage washing, wherein the two-stage washing is respectively provided with a premixing machine, a washing tank with slurry circulation and a horizontal spiral filtering centrifuge with continuous washing function;
In the fly ash washing section, a first-stage premixing machine mixes fly ash and washing liquid of a first-stage spiral filter to form slurry, the slurry is circularly washed in a first-stage washing tank, sodium carbonate solution is injected into the first-stage washing tank to generate calcium carbonate for removing calcium, and then the calcium carbonate is filtered and washed by the first-stage spiral filter to obtain first-stage filtrate, a first-stage filter cake and washing liquid of the first-stage spiral filter, and the first-stage filtrate is collected and sent to a purifying and impurity-removing step of the water treatment section; the second-stage premixing machine mixes the first-stage filter cake and the washing liquid of the second-stage spiral filter to form slurry, the slurry is circularly washed in a second-stage washing tank, and then the slurry is filtered and washed by the second-stage spiral filter to obtain second-stage filtrate, a second-stage filter cake and the washing liquid of the second-stage spiral filter, and the second-stage filtrate is returned to the first-stage spiral filter to be used as the washing liquid in a circulating manner;
in the water treatment section, the primary filtrate enters a purifying and impurity removing step for purifying and impurity removing, then enters a pH adjusting step for adjusting the pH value, and then enters an MVR evaporation salt making step; MVR steam condensate water and fresh water in the MVR evaporation salt making process enter a secondary spiral filter for recycling, and salt obtained after MVR evaporation crystallization enters a chloride storage tank.
MVR exhaust steam at 600Nm 3 The flow rate of about/h is led out from the upper position of the condensate water of the MVR evaporator (about 2% of the MVR steam flow rate), and is added with 60Nm 3 And (3) controlling the temperature of the catalyst bed layer to be 300-315 ℃ by air with the flow rate/h, mixing the outlet steam with the impurity-containing mother liquor after MVR evaporation and crystallization by the catalyst bed layer of the catalytic hydrolysis-combustion treatment reactor, and continuously conveying the mixture to a purification and impurity removal process in a liquid-gas inclusion mode by utilizing the pressure of the residual air flow to carry out absorption treatment.
After the transformation is completed, the device is operated continuously for 3 months. The water washing working section adopts water cement ratio of 3.0, 3.2 and 3.5 respectively for one month, and the average residence time of the slurry in the primary water washing tank is controlled for one month respectively according to 2.0h, 1.6h and 1.0 h; the average residence time of the slurry in the secondary wash tank is the same as that in the primary wash tank. The results included: the total content of the chlorine-containing organic matters with more than six carbon atoms in MVR steam condensate water and the chloride salt solution before purification and impurity removal is reduced to be less than 6mg/kg based on the content of Cl, and the total content of the organic matters with more than six carbon atoms is reduced to be less than 35mg/kg based on the content of C; the total content of the chlorine-containing organic matters with more than six carbon atoms in the water-washed fly ash (dry basis) is reduced to below 21mg/kg based on the content of Cl, and the total content of the organic matters with more than six carbon atoms is reduced to below 118mg/kg based on the content of C; the sedimentation and filtration rate of the fly ash washing slurry are high, the chlorine content of the produced washing fly ash is reduced to below 0.6%, the water content is reduced to below 30%, the power consumption of each ton of fly ash treatment is less than or equal to 110kWh, and the water consumption is less than or equal to 0.6 ton; the device has better process operation elasticity, and the byproduct chloride salt comprises sodium chloride and potassium chloride mixed salt and potassium chloride, which all meet the index requirement of the standard T/CCAS 010-2019 cement kiln of China cement society for the collaborative treatment of fly ash to water-washing chloride of products.
After the transformation is finished, the continuous operation effect of the device for 3 months shows that: after the catalytic hydrolysis-combustion treatment reactor is adopted for the treatment of the exhaust steam, the content of organic components in condensed water including chlorine-containing organic components after MVR steam heating is obviously reduced, after the condensed water flows back to a washing section for recycling, the content of chlorine-containing organic matters such as chlorine-containing polycyclic aromatic ring organic matters and the like in the solution is also correspondingly obviously reduced, the dissolution rate and dissolution quantity of the organic components including the chlorine-containing organic components in the fly ash are obviously improved, the surface properties of powder particles in slurry are changed, the dissolution rate of water-soluble components in the slurry is obviously improved, the slurry is easy to settle and filter, the water content of a filter cake is obviously reduced, and therefore the washing treatment efficiency of the fly ash is also improved.
The washing working section adopts lower water-ash ratio of 3.0, 3.2 and 3.5, and then achieves the technical indexes that the chlorine content of the washing fly ash is less than or equal to 0.6 percent and the water content is less than or equal to 30 percent, and the economic indexes that the water consumption of each ton of fly ash treatment is less than or equal to 0.6 ton, the power consumption is less than or equal to 110kWh (basically no other heat source), and the like, wherein the lower water-ash ratio of 3.0, 3.2 and 3.5 is the basic precondition that the power consumption of each ton of fly ash treatment is less than or equal to 110kWh, and the water content of the washing fly ash is less than or equal to 30 percent is the important precondition that the water consumption of each ton of fly ash treatment is less than or equal to 0.6 ton; and after the outlet steam is mixed with the impurity-containing mother liquor after MVR evaporation and crystallization, the impurity-containing mother liquor after MVR evaporation and crystallization is continuously conveyed to the first-stage filtrate before purification and impurity removal in a liquid-gas inclusion mode by utilizing the pressure of residual air flow, and the heat of the outlet steam after the exhaust steam treatment is utilized, so that the impurity-containing mother liquor after MVR evaporation and crystallization is not easy to crystallize and block in a pipeline for conveying the chloride salt solution before purification and impurity removal.
Example 2
The catalyst of this example was prepared as follows:
(1) With TiO 2 Taking 5.1kg of metatitanic acid powder material based on dry basis and taking H as a raw material 2 SO 4 The sulfur content is 0.21wt percent, and the titanium dioxide powder is obtained by roasting for 4 hours at 410 ℃ under the conditions of a muffle furnace and air;
(2) Preparing 4000g of mixed aqueous solution of ferrous acetate, manganese acetate and cerium acetate with required concentration in a stirring reaction tank, adding 1000g of titanium dioxide powder in the step (1) into the mixed aqueous solution, pulping for 35min, granulating the obtained slurry by hot air spraying at 320 ℃, and cooling to room temperature to obtain granulated powder; the saturated water absorption volume is measured to be 0.51ml/g;
(3) And (3) putting 1000g of the granulated powder obtained in the step (2) into a rotary drum, atomizing and spraying 220ml of ammonium tungstate solution with the required concentration, discharging, bagging and sealing, homogenizing at room temperature for 20h, drying at 100 ℃ for 6h, preparing the dried powder into tablets with phi 6x5mm by a tablet press, and roasting at 400 ℃ for 3h under muffle furnace and air conditions to obtain the catalyst.
In the preparation process, the concentration of the mixed aqueous solution of the ferrous acetate, the manganese acetate, the cerium acetate and the ammonium tungstate solution is calculated according to the weight fraction of FeO 8%, mnO 5% and CeO in the catalyst 2 3%，WO 3 1% of TiO 2 And (5) preparing. The axial compressive strength and the radial compressive strength of the catalyst are respectively 20, and the average values are 316N/particle and 280N/particle.
Example 2 the catalyst application procedure was the same as in example 1.
Example 3
The catalyst of this example was prepared as follows:
(1) With TiO 2 Taking 5.0kg of metatitanic acid powder material based on dry basis and taking H as a raw material 2 SO 4 The sulfur content is 0.21wt percent, and the titanium dioxide powder is obtained by roasting for 3 hours at 400 ℃ under the conditions of a muffle furnace and air;
(2) Preparing 3000g of mixed aqueous solution of ferrous acetate, manganese acetate and cerium acetate with required concentration in a stirring reaction tank, adding 1000g of titanium dioxide powder in the step (1) into the mixed aqueous solution, pulping for 25min, granulating the obtained slurry by hot air spraying at 280 ℃, and cooling to room temperature to obtain granulated powder; the saturated water absorption volume is measured to be 0.45ml/g;
(3) And (3) putting 1000g of the granulated powder obtained in the step (2) into a rotary drum, atomizing and spraying 200ml of ammonium tungstate solution with the required concentration, discharging, bagging, sealing, homogenizing at room temperature for 10 hours, drying at 120 ℃ for 4 hours, preparing the dried powder into tablets with phi 5x3mm by a tablet press, and roasting at 430 ℃ for 2 hours under muffle furnace and air conditions to obtain the catalyst.
In the preparation process, the concentration of the mixed aqueous solution of the ferrous acetate, the manganese acetate, the cerium acetate and the ammonium tungstate solution is calculated according to the weight fraction of FeO 10%, mnO 3% and CeO in the catalyst 2 1.5%，WO 3 2%, the balance being TiO 2 And (5) preparing. The axial compressive strength and the radial compressive strength of the catalyst were measured and were 20, and the average values were 282N/particle and 253N/particle, respectively.
Example 3 the catalyst application procedure was the same as in example 1.
Comparative example 1
The procedure of step (2) and step (3) of example 1 was basically repeated to prepare the catalyst of this comparative example, except that cerium acetate was not added to the mixed aqueous solution of step (2), and the saturated water absorption volume of the granulated powder obtained in step (2) was 0.48ml/g.
The chemical composition of the catalyst of this comparative example was generally: comprises FeO 9%, mnO 4% and WO by weight 3 1.5% and the balance of TiO 2 . The axial compressive strength and the radial compressive strength of the catalyst were measured and were each 20, and the average values were 163N/particle and 132N/particle, respectively.
The catalyst of comparative example 1 could not be used in the next step because of its low axial compressive strength and low radial compressive strength.
Comparative example 2
The procedure of step (2) and step (3) of example 1 was basically repeated to prepare the catalyst of this comparative example, except that in step (3), the granulated powder was not spray-coated with an ammonium tungstate solution, and the saturated water absorption volume of the granulated powder obtained in step (2) was 0.46ml/g.
The chemical composition of the catalyst of this comparative example was generally: in terms of weight fraction, the catalyst contains FeO 9%, mnO 4% and CeO 2 2%, the balance being TiO 2 . Measuring catalysisThe axial compressive strength and the radial compressive strength of the agent are 20 respectively, and the average values are 188N/particle and 150N/particle respectively.
The catalyst of comparative example 2 could not be used in the next step because of its low axial compressive strength and low radial compressive strength.
Catalyst test example 1
The catalysts prepared in examples 1 to 3 and comparative examples 1 to 2 were crushed and sieved to obtain 10ml portions of 60 to 80 mesh, and the reaction performance was tested in a micro-scale evaluation apparatus. At a gas space velocity of 2000h -1 The results of the partial tests at a bed temperature of 320℃are shown in Table 2 below, table 2 being typical compositions of the outlet gases in mg/Nm for the reaction performance tests of the micro-scale evaluation devices for the catalysts of examples 1-3 and comparative examples 1-2 3 。
Condition 1: 1000mg/Nm of 2-chloroanthracene 3 Left and right (containing 167mg/Nm of chlorine) 3 ) Testing the gas conditions of 10% of air by volume and the rest of water vapor for 10 hours;
condition 2: continuing to use 4000mg/Nm of anthracene-containing material 3 Testing the gas conditions of air with the volume of about 15% and the balance of water vapor for 10 hours;
condition 3: continuing to use 500mg/Nm of pyrene 3 Testing the gas conditions of air with the volume of about 10% and the balance of water vapor for 10 hours;
Condition 4: continuing to use 1000mg/Nm of 9-chlorophenanthrene 3 About 3000mg/Nm of anthracene 3 Testing the gas conditions of air with the left and right percent of 15 percent of volume and the rest being water vapor. Wherein the example 1 catalyst was tested under this condition for 200 hours and the example 2-3 and comparative example 1-2 catalysts were tested under this condition for 10 hours.
In the experiment, conditions 1 to 4 were sequentially performed.
TABLE 2 typical composition of the outlet gases of examples 1-3, comparative examples 1-2
The catalysts of examples 1-3 showed substantially no change in the composition of the outlet gas during the test under the conditions described, and no decrease in the composition, indicating that the reaction performance of each catalyst was very stable.
Example 1 catalyst in condition 1, the HCl production rate of chlorine contained in 2-chloroanthracene of the concentration was 92.6%, and CO of carbon contained in 2-chloroanthracene of the concentration was obtained 2 The yield was 93.2%; CO containing carbon for anthracene and pyrene of the concentration in conditions 2 and 3 2 The production rates are 86.8% and 85.6%, respectively, and are all above 85%; in condition 4, the HCl production rate of chlorine contained in 9-chlorophenanthrene of the concentration is 91.4%, and CO containing carbon contained in 9-chlorophenanthrene and anthracene of the concentration 2 The yield was 84.4%. After the test is finished, the catalyst is discharged, and the catalyst is easy to discharge, has no obvious difference between fluidity and the fluidity before the test, and has no pulverization and no adhesion; chlorine content was measured at only 2.7mg/g.
Catalyst test example 2
100ml of the catalyst prepared in example 1 was taken and subjected to a reaction performance test in a small-sized evaluation apparatus. The test conditions were: gas space velocity 600h -1 The bed temperature is 300 ℃; the gas stream contained 500mg/Nm of 2-chloroanthracene 3 About, 9-chlorophenanthrene 500mg/Nm 3 About, anthracene 1000mg/Nm 3 About, phenanthrene 1000mg/Nm 3 About, pyrene 1000mg/Nm 3 About 15% by volume of air and the balance water vapor, for 200h.
During the test, the composition of the outlet gas was not changed basically, indicating that the catalyst of example 1 was very stable in reaction performance; the HCl generation rate of chlorine in the gas stream is always kept at 94-95%, and CO containing carbon is kept 2 The production rate is kept at 84-86% all the time, and the production rate does not decrease. After the test is finished, the catalyst is discharged, and the catalyst is easy to discharge, has no pulverization and no bonding; chlorine content was measured at only 3.1mg/g. The axial compressive strength and the radial compressive strength of the discharged catalyst were measured to be 20 particles each, and the average values were 303N/particle and 260N/particle, respectively, and the mechanical strength was not considered to be reduced.
Claims (9)
1. The water washing and dechlorination treatment process of the household garbage incineration fly ash comprises a fly ash water washing section and a water treatment section; the fly ash washing working section comprises two stages of washing, and the washing water comprises fresh water and MVR steam condensate water; the water treatment working section comprises a purifying and impurity removing working procedure, a pH adjusting working procedure and an MVR evaporation salt making working procedure, and MVR steam condensate water in the MVR evaporation salt making working procedure is sent back to the fly ash washing working section for recycling; the method is characterized in that exhaust steam accounting for 1-3% of the steam flow of MVR is discharged from an MVR evaporator in an MVR evaporation salt making process, 8-15v% of air is added, the temperature of a catalyst bed is controlled to 300-330 ℃ through a catalytic hydrolysis-combustion treatment reactor, organic components enriched in the exhaust steam comprise chlorine-containing organic components and are converted into carbon dioxide and hydrogen chloride, and outlet steam is mixed with impurity-containing mother liquor after MVR evaporation crystallization and then sent to a purification and impurity removal process for absorption and treatment;
The catalytic hydrolysis-combustion treatment reactor is filled with a hydrolysis-combustion treatment catalyst, and the hydrolysis-combustion treatment catalyst comprises the following components: 8-10wt% of FeO; mnO 3-5wt%; ceO (CeO) 2 1.5-3wt%；WO 3 1-2wt%; the balance being TiO 2 ；
In the fly ash washing working section, a primary pre-mixer mixes fly ash and washing liquid of a primary spiral filter to form slurry, the slurry is circularly washed in a primary washing tank, sodium carbonate solution is injected into the primary washing tank to generate calcium carbonate for removing calcium, and primary filtrate, a primary filter cake and washing liquid of the primary spiral filter are obtained through filtration and washing of the primary spiral filter, and the primary filtrate is sent to a purifying and impurity removing working section after being collected; the second-stage premixing machine mixes the first-stage filter cake and the washing liquid of the second-stage spiral filter to form slurry, the slurry is circularly washed in a second-stage washing tank, and then the slurry is filtered and washed by the second-stage spiral filter to obtain second-stage filtrate, a second-stage filter cake and the washing liquid of the second-stage spiral filter, and the second-stage filtrate is returned to the first-stage spiral filter to be used as the washing liquid in a circulating manner;
in the water treatment working section, the primary filtrate enters a purifying and impurity removing step for purifying and impurity removing, then enters a pH adjusting step for adjusting the pH value, and then enters an MVR evaporation salt making step; MVR steam condensate water and fresh water in the MVR evaporation salt making process enter a secondary spiral filter for recycling, and salt obtained after MVR evaporation crystallization enters a chloride storage tank.
2. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 1, characterized in that the preparation method of the hydrolysis-combustion treatment catalyst comprises the following steps:
(1) Roasting the meta-titanic acid powder to obtain titanium dioxide powder;
(2) Preparing a mixed aqueous solution of ferrous acetate, manganese acetate and cerium acetate, adding the titanium dioxide powder obtained in the step (1), pulping, granulating the obtained slurry by hot air spraying at 280-320 ℃, and cooling to room temperature to obtain granulated powder;
(3) And (3) atomizing and spraying an ammonium tungstate solution on the granulated powder obtained in the step (2), discharging, sealing, homogenizing at room temperature, drying, making into tablets, and roasting to obtain the hydrolysis-combustion treatment catalyst.
3. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 2, wherein in the step (1), the roasting temperature is 400-420 ℃, and the roasting time is 2-4h.
4. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 2, wherein in the step (2), the weight ratio of the mixed aqueous solution to the titanium dioxide powder obtained in the step (1) is 3-4:1.
5. The water-washing and dechlorination treatment process of the household garbage incineration fly ash according to claim 2, wherein in the step (3), the volume of the ammonium tungstate solution is 43-46% of the saturated water absorption volume of the granulating powder.
6. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 2, wherein in the step (3), the homogenization treatment time is 10-20h.
7. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 2, wherein in the step (3), the roasting temperature is 400-430 ℃ and the roasting time is 2-3h.
8. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 1, wherein the fly ash water-washing section adopts a water-ash ratio of 3-3.5.
9. The water-washing dechlorination treatment process of the household garbage incineration fly ash according to claim 1, wherein the average residence time of the slurry in the primary water-washing tank and the slurry in the secondary water-washing tank are 1-2h.
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