CN212442519U - Incineration fly ash disposal system - Google Patents

Abstract

The utility model discloses an incineration fly ash processing system, including flying ash melting system, the exhaust-gas washing system, brine refining system and evaporation crystallization system, the batch mixture that will burn flying ash and admixture and make into drops into flying ash melting system, produce the volatile gas and form the slag after high temperature melting, the volatile gas gets into the exhaust-gas washing system, spray washing treatment through alkali lye and introduce the chimney of power plant after up to standard and concentrate the emission, and the solid-liquid result after spraying the washing forms the crystallization salt liquid through the crystallization of precipitating, make solid-state crystallization salt through the first crystallization separation, after getting into brine refining system and making brine again, get into the evaporation crystallization system, make industrial salt through evaporation crystallization and second crystallization separation. The utility model discloses full play waste incineration power plant's synergistic effect, and only handle the fly ash that burns that produces in the factory, belong to the self-production self-processing of hazardous waste, reducible a lot of environmental protection link of approving. The utility model discloses can realize the processing target of innoxious, resourceization and minimizing of burning flying dust.

Description

Incineration fly ash disposal system

Technical Field

The utility model belongs to the technical field of solid waste handles, especially, relate to an incineration fly ash handles system.

Background

With the development of socioeconomic in China and the improvement of the living standard of people, the process of urbanization is rapidly promoted, and the generation amount of municipal domestic waste is continuously increased at the speed of 8-10% per year. According to statistics, the total amount of the domestic garbage in 2001 is 1.3 hundred million tons, 1.5 hundred million tons in 2010, and reaches 2.0 hundred million tons in 2016. Untreated municipal solid waste causes a large amount of land occupation, seriously pollutes the environment and harms human health.

The waste incineration treatment presents a good development trend in China and is considered as an important direction for treating urban waste in China. The incineration method conforms to the recycling, reduction and harmless principles of garbage treatment. The weight of the garbage can be reduced by 75-95% through incineration treatment, the volume of the garbage can be reduced by 70-90%, and heat generated by incineration can be used for heat supply or power generation. Although the initial investment of the process equipment of the large-scale mechanized incinerator is high, the process equipment has small floor area, can be close to the urban area and has low transportation cost. The advantages are prominent, and the incineration treatment of the garbage is developed rapidly. According to the Chinese municipal solid waste industry investment analysis report (2012), the total amount of accumulated investment of Chinese waste incineration projects from 1998 to 2012 reaches 1469 million yuan, and 449 projects are total. By 2017, 350 waste incineration power plants are operated and treat 34.65 million tons of waste daily.

With the significant increase in the amount of waste incineration, the total amount of fly ash produced therefrom is quite large. The fly ash is residue collected in a flue gas purification system of a waste incineration plant, and the total amount of the fly ash is 3-5% of the waste treatment amount. Waste incineration fly ash is typically a light gray, fine particle with a whitish spot with some black particles (unburned carbon) mixed in. The fly ash contains trace heavy metals such as Cr, Cd, Hg, Pb, Cu, Ni and the like and organic pollutants such as dioxin, furan and the like, and is defined as hazardous waste with the code HW 18. If the fly ash is not treated properly, the harmful substances in the fly ash can cause serious pollution accidents and harm the health of residents. Heavy metals and dioxins in fly ash can cause new environmental problems. Heavy metals are harmful in that they cannot be decomposed by microorganisms but can be enriched in or form other more toxic compounds in organisms and finally cause harm to human bodies through food chains, and low doses of these pollutants can cause disturbance of the metabolism of the human bodies and induce diseases and even death. Dioxin organic substances are substances with strong toxicity, particularly T4CDD (2, 3, 7, 8-TCDD) has the strongest toxicity, and the toxicity is 500 times that of strychnine and 1000 times that of cyanide.

At present, the disposal modes of incineration fly ash mainly include solidification and landfill, cement kiln cooperation, plasma furnace melting and the like.

1. Curing and burying: the fly ash, the cement, the chelating agent and the water are fed into a mixing device to be mixed, and heavy metal substances in the fly ash react with the chelating agent to generate a chelate so as to be stabilized. The stabilized fly ash and the cement paste from the mixing device are made into fly ash cement blocks by a block making machine and sent into a curing room for curing. And conveying the cured fly ash cement blocks to a specified place for landfill by a special brick conveying vehicle. This approach has the advantage of simplicity, but has the disadvantages of: the weight (volume) of the solidified fly ash cement blocks is increased by about one time, the fly ash cement blocks can occupy a large amount of storage capacity of a landfill during the landfill process, so that the utilization efficiency of the landfill is greatly reduced, if the storage capacity investment of the landfill is considered, the treatment cost is higher, and the treatment targets of harmlessness, reclamation and reduction of the fly ash can not be realized.

2. Synergy of the cement kiln: the fly ash is directly sprayed or put into a high-temperature section of a cement kiln after being pretreated by water washing, and the harmful substances in the fly ash are treated and absorbed by utilizing a powerful temperature field and a powerful material field in the cement production process. The fly ash becomes a component of cement clinker after being calcined by the cement kiln, and the final disposal of the fly ash is realized. But the disadvantages are: fly ash contains a large amount of chlorine, which directly affects the production of cement clinker and the quality of cement products.

3. Melting in a plasma furnace: mixing the fly ash, the admixture, the coke and other materials, feeding the mixture into a plasma furnace, igniting the coke by combustion-supporting air blown from the outside, and quickly forming high temperature and melting the fly ash and the admixture under the action of a plasma torch to passivate and solidify harmful substances in the fly ash. But the disadvantages are: the plasma torch has the advantages of high temperature in the furnace and short service life; flue gas generated by burning coke needs secondary burning out and purification treatment, energy consumption is high, and generated secondary fly ash is still dangerous waste; and the processing capacity of the existing plasma furnace is small and is generally below 1 t/h.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a fly ash incineration disposal system that is with low costs, full play synergistic effect, realizes the innoxious, resourceization and the minimizing of fly ash incineration.

The purpose of the utility model is realized through the following technical measures: a burning fly ash disposal system comprises a fly ash melting system, a waste gas washing system, a brine refining system and an evaporative crystallization system which are connected in sequence, wherein a batch mixture prepared from burning fly ash and admixture is put into the fly ash melting system, volatile gas is generated and forms slag after high-temperature melting, the volatile gas enters the waste gas washing system, is led into a chimney of a power plant to be discharged in a centralized manner after being treated by alkali liquor spraying and washing to reach the standard, a solid-liquid product after spraying and washing is precipitated and crystallized to form crystallized salt liquid, solid crystallized salt is prepared by primary crystallization and separation, and then the solid-liquid product enters the brine refining system to be prepared into brine, enters the evaporative crystallization system, and is prepared into industrial salt through evaporative crystallization and secondary crystallization and separation.

The utility model discloses high temperature melting can make the whole decompositions of dioxin class material in the fly ash of burning, and in addition, the slag is quenched after coming out of the stove, and the heavy metal that probably exists melts admittedly completely, forms stable glass state material. Spraying and washing the volatile gas with alkali liquor to form a solid-liquid product, and finally preparing industrial salt; the utility model uses the rest cullet and partial slag after the waste incineration of the power plant as admixture, the generated slag can be disposed by using the existing channel of the slag of the power plant, the volatile gas is led into the chimney of the power plant after being disposed and is discharged in a centralized way, and the discharge port is not separately arranged, so that the synergistic effect of the waste incineration power plant can be fully exerted; moreover, the utility model discloses only handle the fly ash that burns that produces in the factory, belong to the self-production self-processing of hazardous waste, reducible a lot of environmental protection examination and approval links. The utility model discloses can realize the processing target of innoxious, resourceization and minimizing of burning flying dust.

The utility model discloses a fly ash melting system includes high temperature melting furnace and is used for carrying the batch to the feed subsystem of high temperature melting furnace, high temperature melting furnace is the full electric furnace of cold top structure, and its inner space is including the melting room that is used for melting high temperature melt and the material way clean room that is used for modulating high temperature melt, the material way clean room has the dust and subsides the structure, the melting room through the throat and through rising the throat with the material way clean room communicates with each other, be equipped with the slag export that is used for discharging the slag and be used for discharging the volatile gas export of volatilizing the gas on the material way clean room, the slag export is less than the liquid level of high temperature melt and makes high temperature melt form homogenized melt through throat, rising the throat in proper order, flows into the material way clean room; the top surfaces of the melting chamber and the material channel purifying chamber are provided with air guide flues communicated with the melting chamber and the material channel purifying chamber, the homogenized melt in the material channel purifying chamber meets volatile gas from the air guide flues, partial heat is transferred to the volatile gas, and dust settled from the volatile gas is absorbed and melted.

The feed subsystem is including blending feed bin, flying ash storehouse, the mixed conveying mechanism of weighing, batch surge bin and gyration feeder, the mixed conveying mechanism of weighing is located the below of blending feed bin and flying ash storehouse for weigh respectively to the admixture with burn the flying ash and prepare the batch mixture and carry to batch surge bin, the gyration feeder has feed end and feed end, the feed end is located the below of batch surge bin, is used for receiving the batch mixture, the feed end stretches into fan-shaped rotary motion is done to the top of the high temperature fuse-element in the melting chamber, so that lay the batch mixture on the liquid level of high temperature fuse-element uniformly.

In order to ensure the stability of fly ash feeding and avoid the influence on fly ash feeding when air conveying feeding, the fly ash bin adopts the combination of two bins, and when one fly ash bin is feeding, the other fly ash bin can be used for feeding.

The blending bin adopts a two-bin or three-bin combination and is used for storing different blending materials so as to meet the batching requirements of slag components.

The waste gas washing system of the utility model comprises a spray tower, a washing tower, a precipitation crystallization kettle, a first filtering centrifuge and an alkali liquor preparation subsystem, wherein the spray tower is provided with a volatile gas inlet, an alkali liquor outlet and a volatile gas outlet for the volatile gas from a fly ash melting system to enter, the washing tower is provided with a volatile gas inlet, a volatile gas outlet, an alkali liquor inlet and an alkali liquor outlet, the volatile gas outlet of the spray tower is connected with the volatile gas inlet of the washing tower, and the volatile gas after washing and purification is sent to a chimney of a power plant to be discharged; the alkali liquor inlet of the spray tower is connected with the alkali liquor inlet of the washing tower through a circulating alkali liquor pipeline, and the alkali liquor outlet of the spray tower is connected with the circulating alkali liquor pipeline so as to guide the alkali liquor at the bottom of the spray tower into the spray tower to realize the circulation of the alkali liquor in the spray tower; the alkali liquor outlet of the washing tower is connected with a circulating alkali liquor pipeline so as to guide the alkali liquor at the bottom of the washing tower into the washing tower to realize circulation of the alkali liquor in the washing tower; the precipitation crystallization kettle is provided with an alkali liquor inlet, a crystallized salt liquid outlet and a dilute salt liquid outlet, the alkali liquor inlet of the precipitation crystallization kettle is connected with the alkali liquor outlet of the spray tower, the crystallized salt liquid outlet is connected with a first filtering centrifugal machine, the dilute salt liquid outlet is connected with the alkali liquor preparation subsystem, the crystallized salt liquid formed at the bottom of the precipitation crystallization kettle enters the first filtering centrifugal machine to be crystallized and separated for the first time to form solid-state crystallized salt, the solid-state crystallized salt is conveyed to the brine refining system, the separated dilute salt liquid enters the alkali liquor preparation subsystem, and the alkali liquor preparation subsystem is connected with the alkali liquor inlet of the washing tower.

In order to meet the washing requirement of the volatile gas, the washing tower can be a single tower or a double-tower combination, and the washing device in the tower can also be two or more sets of combination. The washing process is slightly different for different combinations.

The alkali liquor preparation subsystem mainly comprises an alkali liquor preparation tank, a reaction precipitation kettle and a first mother liquor box, wherein the first mother liquor box is provided with a first dilute salt liquor inlet connected with the precipitation crystallization kettle, a second dilute salt liquor inlet connected with the first filtering centrifuge and a dilute salt liquor outlet, the reaction precipitation kettle is provided with a dilute salt liquor inlet, a charging opening for adding a precipitator and a precipitation liquor outlet, the dilute salt liquor outlet of the first mother liquor box is connected with the dilute salt liquor inlet of the reaction precipitation kettle through a dilute salt liquor conveying pipeline, and the precipitation liquor outlet is connected with the brine refining system; the alkali liquor preparation tank is provided with a feed inlet for adding solid sodium hydroxide, a first dilute salt solution inlet, a water adding port and an alkali liquor outlet, and the first dilute salt solution inlet is connected to a dilute salt solution conveying pipeline and is used for guiding the dilute salt solution of the first mother liquor tank into the alkali liquor preparation tank; and the alkali liquor inlet of the washing tower is connected with the alkali liquor preparation subsystem.

The brine refining system comprises a brine melting tank, a membrane filter, a primary brine tank, an ion exchange resin tower, a refined brine tank, a brine sludge liquid collecting tank, a plate-and-frame filter press and a filter pressing water return tank, wherein the brine melting tank is provided with a water filling port, a feed port, a supernatant outlet and a precipitate outlet, the feed port is used for inputting solid-state crystallized salt from an exhaust gas washing system and adding a precipitator, the membrane filter is provided with a supernatant inlet, a primary brine outlet and a filtrate outlet, the supernatant inlet is connected with the supernatant outlet of the brine melting tank, the primary brine outlet is connected with the primary brine tank, the ion exchange resin tower and the refined brine tank in sequence, and the refined brine tank is connected with the evaporative crystallization system; salt mud liquid collection tank has deposit entry, filtering material entry, precipitation liquid entry, salt mud liquid export and supernatant export, the precipitation liquid entry with reation precipitation cauldron's precipitation liquid exit linkage, the filtering material entry with membrane filter's filtering material exit linkage, the deposit entry with change salt tank's deposit exit linkage, the supernatant export with filter-pressing return water tank connects, the plate and frame pressure filter has salt mud liquid entry, pressure filtrate export and salt mud export, salt mud liquid entry with salt mud liquid exit linkage of salt mud liquid collection tank, pressure filtrate export with filter-pressing return water tank connects, the salt mud export is used for discharging the salt mud that the filter-pressing came out.

The ion exchange resin tower can be a combination of two towers or a combination of three towers, and the ion exchange processes of different combinations are slightly different.

The refined brine tank adopts a three-tank combination: one tank is used for storing the detected refined brine and supplying liquid for the evaporative crystallization system; a tank for receiving the refined brine from the ion exchange resin column; one for standby. The volume of the tank body is designed according to the amount of refined brine required by one class.

The membrane filter can be a microfiltration membrane filter, an ultrafiltration membrane filter or a nanofiltration membrane filter, and the filtration process of different types of membrane filters is slightly different.

The salt dissolving tank adopts a three-tank combination: one tank is used for storing prepared brine and supplying liquid to the membrane filter; one tank is used for dissolving salt and preparing brine; a tank is provided for receiving the return condensate. The volume of the tank body is designed according to the amount of salt water needed by one shift.

The evaporation crystallization system of the utility model comprises an evaporation subsystem, an evaporation crystallization kettle and a second filtering centrifuge, wherein the evaporation subsystem comprises at least two sets of evaporators with heaters and separators, the heaters and the separators of each set of evaporators are connected to form a brine circulation loop in which brine flows circularly, the brine circulation loops of the evaporators are connected through a brine circulation connecting pipeline, the separator of each evaporator positioned in front of the last evaporator is connected with the heater of the adjacent evaporator behind the separator through a secondary steam outlet, the heater of each evaporator is provided with a condensed water outlet, the heater of the first evaporator is also provided with a refined brine inlet connected with the refined brine tank and a steam inlet used for inputting external steam, the heater of each evaporator positioned behind the first evaporator is also provided with a noncondensable gas outlet, the separator of the last evaporator is also provided with a secondary steam outlet and a crystallized salt solution outlet used for discharging the secondary steam, the evaporative crystallization kettle is provided with a crystallized salt liquid inlet, a dilute salt liquid outlet and a crystallized salt liquid outlet, the crystallized salt liquid outlet of the final evaporator is connected with the crystallized salt liquid inlet of the evaporative crystallization kettle, the crystallized salt liquid outlet of the evaporative crystallization kettle is connected with the second filtering centrifugal machine, and the crystallized salt liquid is crystallized and separated for the second time by the second filtering centrifugal machine to form solid industrial salt which is discharged

The evaporative crystallization system of the utility model also comprises a condenser, a condensate water tank and a second mother liquor tank, wherein the condensate water outlet of each evaporator is connected with the condensate water tank, the non-condensable gas outlet of each evaporator and the secondary steam outlet of the last evaporator are connected with the steam inlet of the condenser, and the condensate water outlet of the condenser is connected with the condensate water tank; and a dilute salt solution outlet of the evaporative crystallization kettle is connected with a second mother solution tank, dilute salt solution separated by a second filtering centrifuge is introduced into the second mother solution tank, and the separator of the last evaporator is also provided with a dilute salt solution inlet which is connected with a dilute salt solution outlet of the second mother solution tank, so that the dilute salt solution flows back to the separator of the last evaporator and is evaporated and concentrated again.

The end position evaporator separator bottom of evaporation crystallization system still has the import of crystallization salt liquid, and this crystallization salt liquid access connection is in on the pipeline between the crystallization salt liquid export of end position evaporator and the crystallization salt liquid entry of evaporation crystallization cauldron. The part of the crystallized salt liquid flowing to the evaporative crystallization kettle from the last evaporator separator enters the bottom of the separator through a crystallized salt liquid inlet, and the crystallized salt liquid at the bottom of the separator is stirred to prevent the sodium chloride crystal nucleus from being crystallized and adhered to the wall in the separator.

The alkali liquor preparation tank of the utility model is also provided with a second dilute brine inlet, and a second mother liquor box of the evaporative crystallization system is connected with the second dilute brine inlet of the alkali liquor preparation tank; the filter pressing water return tank is connected with a water filling port of the alkali liquor preparation tank and is used for guiding filter pressing water and connecting process water from the outside; a water injection port of the salt melting tank is connected with the condensed water tank and is used for inputting condensed water and can be accessed into tap water from the outside;

compared with the prior art, the utility model has the advantages of following showing:

the method fully exerts the synergistic effect: the process system is used as a matched facility of the waste incineration fly ash, and can be directly built in a waste incineration power plant; the rest cullet and partial slag after the garbage incineration can be used as admixture; slag generated after the incineration fly ash is melted at high temperature can be disposed by utilizing the existing channel of slag; and the volatile gas is sprayed, washed, treated and then led into the existing chimney of the power plant to be discharged in a centralized manner.

The environment-friendly approval link is reduced: the high-temperature melting facility is directly built in a waste incineration power plant, only the incineration fly ash generated in the plant is treated, the high-temperature melting facility belongs to the self-production and self-treatment of hazardous wastes, and a plurality of environmental approval links can be reduced.

The volatile gas discharge port is not separately arranged: the high-temperature melting furnace is an all-electric melting furnace, incineration smoke is avoided, the amount of gas to be treated is small, the volatile gas is sprayed, washed and treated to reach the standard (GB 18485), and then is introduced into the existing chimney of the power plant to be intensively discharged, a discharge port is not separately arranged, and the construction cost is reduced.

Fourthly, effectively controlling heavy metal to escape: the electric melting furnace adopts a cold top structure, harmful substances such as volatile heavy metals and the like are condensed and absorbed by upper-layer cold materials and react with other elements at a melting interface to generate a more refractory and difficultly volatile compound, and the compound enters the melt again and forms slag after being quenched along with the melt.

Fifthly, secondary fly ash is not generated: the dust generated in the high-temperature melting process is basically discharged out of the melting furnace in the form of slag after being purified by the melting furnace material channel purifying chamber, and no secondary fly ash is generated.

Sixthly, performing twice crystallization separation on sodium chloride: the purpose of the first crystallization separation is to realize the separation of sodium chloride and alkali liquor and avoid the direct entry of high-concentration alkali liquor into an evaporator. The volatile gas amount is less, the amount of alkali liquor used for spray washing is small, the content of chlorine element in the volatile gas is higher, the content of sodium chloride in the alkali liquor after spray washing is higher, and sodium chloride crystal precipitates are easy to form. The purpose of the second crystallization separation is to produce industrial salt as required in Industrial salt (GB/T5462-2015).

Heavy metal complete solid solution: the temperature in the melting furnace is as high as 1500 ℃, slag is quenched after being discharged, and possible heavy metals are completely melted to form a stable glassy substance.

And the dioxin is totally decomposed: the temperature in the melting furnace is high, the retention time of volatile gas is long, and dioxin substances are decomposed completely at high temperature.

The self-supporting utility model can realize the harmless, resource and reduction treatment target of the incineration fly ash, and is suitable for wide popularization and application.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the overall composition structure of the process system of the present invention;

FIG. 2 is a schematic diagram of the fly ash melting system of the present invention;

FIG. 3 is a schematic diagram of the exhaust gas scrubbing system of the present invention;

FIG. 4 is a schematic diagram of the brine refining system of the present invention;

fig. 5 is a schematic diagram of the structure of the evaporative crystallization system of the present invention.

In the figure: 10-fly ash melting system, 101-blending bin, 102-weighing belt, 103-fly ash bin, 104-feeding reamer, 105-weighing reamer, 106-zipper conveyor, 107-hoister, 108-batch buffer bin, 109-rotary feeder, 110-high temperature melting furnace, 111-quenching slag extractor, 20-waste gas washing system, 201-spray tower, 202-washing tower, 203-exhaust fan, 204-spray tower circulating pump, 205-washing tower circulating pump, 206-precipitation crystallizing kettle, 207-first filtering centrifuge, 208-first mother liquor tank, 209-crystallized salt liquor circulating pump, 210-alkali liquor preparation tank, 211-alkali liquor feeding pump, 212-reaction precipitating kettle, 213-circulating alkali liquor pipeline, 214-dilute salt liquor conveying pipeline, 30-brine refining system, 301-salt melting tank, 302-salt melting water pump, 303-membrane filter, 304-primary brine tank, 305-primary brine pump, 306-ion exchange resin tower, 307-refined brine tank, 308-refined brine pump, 309-brine sludge liquid collecting tank, 310-brine sludge pump, 311-plate-and-frame filter press, 312-filter pressing water return tank, 313-filter pressing water return pump, 40-evaporative crystallization system, 401-one-effect evaporator, 402-two-effect evaporator, 403-crystallized salt liquid discharge pump, 404-evaporative crystallization kettle, 405-second filter centrifuge, 406-second mother liquor tank, 407-crystallized salt liquid reflux pump, 408-condenser, 402-409 condensed water tank, 410-condensed water pump, 411-vacuum pump, 412-lower pipe section of the circulation loop, 413-brine circulation connecting pipeline.

Detailed Description

As shown in FIG. 1, the utility model provides a fly ash incineration disposal system can be directly built in the waste incineration power plant as the supporting facilities of the fly ash incineration, and the synergistic effect of the waste incineration power plant is fully exerted. The system comprises a fly ash melting system 10, a waste gas washing system 20, a brine refining system 30 and an evaporative crystallization system 40 which are connected in sequence, wherein a batch prepared by burning fly ash and admixture is put into the fly ash melting system 10, volatile gas is generated and forms slag after high-temperature melting, the volatile gas enters the waste gas washing system 20, is led into a chimney of a power plant to be intensively discharged after being sprayed and washed by alkali liquor to reach the standard, a solid-liquid product after being sprayed and washed is precipitated and crystallized to form crystallized salt liquid, solid crystallized salt is prepared through first crystallization and separation, and then enters the brine refining system 30 to be prepared into brine, and then enters the evaporative crystallization system 40, and industrial salt is prepared through evaporative crystallization and second crystallization and separation.

As shown in fig. 2, the fly ash melting system 10 includes a high temperature melting furnace 110 and a feeding subsystem for feeding the batch materials to the high temperature melting furnace 110, the feeding subsystem includes a blending bin 101, a fly ash bin 103, a weighing mixing conveying mechanism, a batch buffer bin 108 and a rotary feeder 109, and the incineration fly ash of the waste incineration power plant is fed into the fly ash bin 103 for temporary storage via an air feeding system. The weighing and mixing conveying mechanism comprises a feeding reamer 104, a weighing reamer 105, a weighing belt 102, a zipper conveyor 106 and a lifter 107, wherein the feeding reamer 104 is positioned below the fly ash bin 103, the weighing reamer 105 is positioned below the feeding reamer 104, the weighing belt 102 is positioned below the blending bin 101, and the zipper conveyor 106 is positioned below the weighing reamer 105 and the weighing belt 102. The feeding reamer 104 is provided with a variable frequency speed regulating motor, and the feeding amount of the fly ash can be controlled by adjusting the rotating speed of the reamer. The weighing reamer 105 is provided with a weighing module, and can accurately weigh the weight of the fly ash. The fly ash from the fly ash bin 103 is weighed by a weighing combination consisting of a feeding reamer 104 and a weighing reamer 105, and then quantitatively fed into a zipper conveyor 106. In order to ensure the stability of fly ash feeding and avoid the influence on fly ash feeding when air is fed, the fly ash bin can adopt a combination of two bins, and when one fly ash bin is feeding, the other fly ash bin can be used for feeding.

The admixture is mainly from cullet and partial slag left after the garbage incineration. After the materials are mixed, if the materials can not meet the requirements of slag components, some silicon-calcium materials can be purchased from the market to be matched. The admixture is sent into a blending bin 101 for temporary storage through an electric hoist. The admixture is weighed by the weighing belt 102 and then quantitatively fed to the zipper conveyor 106. The blending bin 101 adopts a two-bin or three-bin combination and is used for storing different blending materials so as to meet the batching requirements of slag components.

The fly ash and admixture are combined on the zipper conveyor 106 to form a batch. The batch is fed via a zip conveyor 106 and a hoist 107 into a batch surge bin 108. A rotary feeder 109 is arranged below the batch buffer bin 108, the rotary feeder 109 has a feeding end and a feeding end, the feeding end is positioned below the batch buffer bin 108 and is used for receiving batch, and the feeding end extends into the high-temperature melting furnace 110 to feed the batch into the high-temperature melting furnace.

The high-temperature melting furnace 110 is an all-electric melting furnace with a cold roof structure, and melts materials in a vertical melting mode. The electrode is horizontally inserted from the side wall of the high-temperature melting furnace body to provide heat for the high-temperature melting furnace. The feeding end of the rotary feeder 109 extends into the furnace body from the inlet of the 110 high-temperature melting furnace, and makes fan-shaped rotary motion in the furnace body, so that the batch is uniformly spread on the liquid level of the high-temperature melt to form a batch covering layer, thereby preventing the high-temperature melt from carrying out heat radiation to the top of the furnace and reducing the temperature of the upper space of the furnace body to below 150 ℃. The batch in the covering layer, which is in contact with the liquid level of the high-temperature melt, absorbs the heat transferred from the high-temperature melt and is gradually melted to form the high-temperature melt. While the batch is melted by the high-temperature melt, the batch is continuously and uniformly added onto the covering layer by the rotary feeder 109, the thickness of the covering layer of the batch is maintained, and the continuous operation of the fly ash melting system is ensured.

The inner space of the high-temperature melting furnace 110 comprises a melting chamber for melting high-temperature melt and a material channel purifying chamber for preparing the high-temperature melt, the melting chamber is communicated with the material channel purifying chamber through a liquid flow hole and an ascending material channel, the material channel purifying chamber is provided with a slag outlet for discharging slag and a volatile gas outlet for discharging volatile gas, the slag outlet is lower than the liquid level of the high-temperature melt, so that the high-temperature melt sequentially passes through the liquid flow hole and the ascending material channel to form homogenized melt, and flows into the material channel purifying chamber, and in the flowing process, the high-temperature melt is subjected to component homogenization and thermal homogenization continuously under the action of certain chemical components and heat force to form relatively uniform melt, and at the moment, the temperature of the melt is about 1300-1500 ℃. The top surfaces of the melting chamber and the material channel purifying chamber are provided with air guide flues communicated with the melting chamber and the material channel purifying chamber, the homogenized melt is properly cooled in the material channel purifying chamber and meets volatile gas from the air guide flues, partial heat is transferred to the volatile gas, and dust settled from the volatile gas is absorbed and melted. The melt after moderate cooling has a certain viscosity, and is discharged from a slag outlet of the high-temperature melting furnace 110 under the action of position difference, falls into a quenching slag extractor 111, and is quenched by water to form slag.

The main chemical elements of various glasses used in daily life include silicon, aluminum, iron, calcium, magnesium, potassium, sodium, boron, lithium, barium, lead, zinc and the like. In addition, chemical elements such as sulfur, chlorine, fluorine, arsenic, selenium, antimony, cerium, cobalt, nickel, copper, manganese, chromium, cadmium, silver, gold and the like can be used as fluxing agents and coloring agents in the glass production process.

The above chemical elements are present in the fly ash to a greater or lesser extent depending on the formation process of the incineration fly ash. After addition of appropriate admixtures to the fly ash, a glassy melt can be formed. The main chemical elements in the fly ash and the admixture become vitreous slag after quenching. After finishing the fluxing function and the coloring function, the heavy metal elements without volatility are completely and fixedly melted in the slag, and the heavy metal elements with volatility are partially volatilized and partially and fixedly melted in the slag.

The slag from the quenching slag extractor 111 is sent to a slag warehouse for temporary storage, is transported to a use point by an automobile by virtue of the existing incineration slag disposal channel of a waste incineration power plant, and is directly applied to building material activities such as brick making, paving and the like.

In the process that the batch absorbs the heat transferred by the high-temperature melt and is gradually melted, the moisture in the batch is firstly evaporated, the water vapor penetrates through the batch covering layer and is emitted into the upper space of the furnace body, and the water vapor transmits part of the heat to the batch in the process of penetrating through the batch covering layer; then, carbonate such as sodium carbonate, calcium carbonate and the like is heated and decomposed to release carbon dioxide, the carbon dioxide penetrates through the batch covering layer and is emitted into the upper space of the furnace body, and the carbon dioxide transmits partial heat to the batch in the process of penetrating through the batch covering layer; finally, the chlorofluorocarbon and volatile heavy metal elements which have entered the melt volatilize, pass through the melting interface and the batch coating in the form of microbubbles, and are emitted to the upper space of the furnace body, and because of the condensation property of the elements, a part of the elements are condensed and adsorbed in the penetration process, react with other elements at the melting interface to generate a more refractory and difficultly volatile compound, enter the melt again, and are quenched together with the melt to form slag.

Besides heavy metals, dioxin and furan are harmful substances in the fly ash. Dioxins and furans are extremely potent carcinogenic organisms. Most dioxin and furan enter the melt along with the fly ash and are decomposed into water vapor, carbon dioxide and other small molecules at high temperature; a few of dioxin and furan can be volatilized and pass through the batch covering layer to be emitted into the upper space of the furnace body. In addition, the rotary feeder 109 can raise a small amount of fly ash dust during feeding, and the dust also contains a certain amount of dioxin and furan. From the above analysis, it can be seen that the volatile gas in the upper space of the furnace body contains dust, moisture, carbon dioxide, dioxin, furan, chlorofluorocarbons, volatile heavy metals, and the like.

The volatile gas enters the material channel purifying chamber through the air guide flue at the top of the furnace body of the high-temperature melting furnace 110 under the action of the suction force of the external fan, absorbs partial heat of the high-temperature melt, and the temperature rises to over 1000 ℃ quickly. The material channel purifying chamber is provided with a dust settling structure. The volatile gas comes from the volatilization of the batch, the gas quantity is little, and the flow velocity in the material channel purifying chamber is very slow. Most of dust in the volatile gas is settled under the action of a dust settling structure, is absorbed and melted by the high-temperature melt, is discharged as part of the melt, and forms slag after quenching. Because the temperature of the volatile gas in the material channel purifying chamber is high (above 1000 ℃), the gas quantity is small, the retention time is long, and dioxin and furan possibly existing in the volatile gas are all decomposed into water vapor, carbon dioxide and other small molecules. The volatile gas is discharged from the volatile gas outlet of the high-temperature melting furnace 110 after removing dust, dioxin, and furan in the material path purifying chamber, and enters the exhaust gas scrubbing system 20.

As shown in fig. 3, the exhaust gas washing system 20 includes a spray tower 201, a washing tower 202, a precipitation crystallization kettle 206, a first filtering centrifuge 207 and an alkali liquor preparation subsystem, the spray tower 201 has a volatile gas inlet, an alkali liquor outlet and a volatile gas outlet, the washing tower 202 has a volatile gas inlet, a volatile gas outlet, an alkali liquor inlet and an alkali liquor outlet, the volatile gas outlet of the spray tower 201 is connected with the volatile gas inlet of the washing tower 202, and the washed and purified volatile gas is sent to a chimney of a power plant for emission; an alkali liquor inlet of the spray tower 201 is connected with an alkali liquor inlet of the washing tower 202 through a circulating alkali liquor pipeline 213, and an alkali liquor outlet of the spray tower 201 is connected with the circulating alkali liquor pipeline 213. The high-temperature volatile gas from the fly ash melting system 10 enters the spray tower 201 from the volatile gas inlet of the spray tower 201, and the temperature is rapidly reduced to 60-90 ℃ under the spraying of circulating alkali liquor in the spray tower. Because the amount of the volatile gas is small, the circulating alkali liquor is excessively sprayed, so most of the circulating alkali liquor flows back to the bottom of the spray tower except a small amount of evaporation, the circulating alkali liquor is lifted to an alkali liquor inlet of the spray tower 201 by the spray tower circulating pump 204 and enters a spraying device in the spray tower to be sprayed in the spray tower, the temperature of the volatile gas is rapidly reduced, and the circulation of the alkali liquor in the tower is realized. Besides reducing the temperature of the volatile gas, the circulating alkali liquor can also absorb part of the sulfur, chlorine and fluorine in the volatile gas and the harmful components such as volatile heavy metals. After the temperature of the volatile gas is reduced and a part of harmful components are removed, the volatile gas enters the volatile gas inlet of the washing tower 202 from the volatile gas outlet of the spray tower 201 and is continuously purified under the washing of circulating alkali liquor in the washing tower. And after absorbing the residual harmful components in the volatile gas, the circulating alkali liquor reflows to the bottom of the washing tower. The lye outlet of the washing tower 202 is connected with a circulating lye pipeline 213, circulating lye flows out from the lye outlet of the washing tower 202 and is lifted to the lye inlet of the washing tower 202 by a washing tower circulating pump 205, and then enters a washing device in the washing tower to wash and purify volatile gas, thereby realizing lye circulation in the tower.

In order to meet the scrubbing requirements of the volatile gas, the scrubber 202 may be a single tower or a combination of two towers, or two or more sets of scrubbing devices may be provided in the towers. The washing process is slightly different for different combinations. The volatile gas after washing and purification meets the discharge requirement of the pollution control Standard for incineration of domestic garbage (GB 18485-2014), is extracted by the exhaust fan 203 and is sent to the existing chimney of the waste incineration power plant for discharge, and an independent discharge port is not required to be added. Because the amount of the volatile gas is small, the existing emission index of the waste incineration power plant is not increased basically.

The main harmful components of the volatile gas discharged from the upper space of the furnace body are dust, dioxin, furan, chlorofluorocarbon and volatile heavy metal elements. After dust, dioxin and furan are removed in the material passage purifying chamber of the high-temperature melting furnace 110, the remaining harmful components are chlorofluorocarbons and volatile heavy metal elements, and the remaining harmful components enter the exhaust gas scrubbing system 20 along with the volatile gas and are scrubbed and absorbed in the alkali solution in the exhaust gas scrubbing system 20. According to the fly ash detection result of the conventional waste incineration power plant at present, the content of sulfur and chlorine is very high, and fluorine and volatile heavy metal elements are trace elements or trace elements. Therefore, the harmful components absorbed by the alkali liquor are mainly sulfur and chlorine, and are doped with a small amount of fluorine and volatile heavy metal elements.

Since the incineration fly ash itself contains much moisture (adsorbed water and water of combination), a part of chlorine element volatilized from the melt exists in the form of hydrogen chloride. Chlorine not bound to hydrogen may be present as chlorine gas or as heavy metal chlorides. The sulphur which is evaporated from the melt will for the most part be present in the form of sulphur dioxide. The compounds can generate a series of reactions in alkali liquor, consume sodium hydroxide, and generate substances such as sodium chloride, sodium sulfate, sodium chlorate, sodium fluoride, heavy metal hydroxides and the like, wherein the sodium chloride is taken as the main component, and most of the heavy metal hydroxides are precipitates.

Fluorine and heavy metal elements are trace elements or trace elements, and the proportion of sodium fluoride and heavy metal hydroxide in the solution after the reaction is very small. The main substances in the solution after the reaction are sodium chloride, sodium sulfate, sodium chlorate and sodium hydroxide, thereby forming a five-element system mainly comprising sodium chloride-sodium sulfate-sodium chlorate-sodium hydroxide-water. In the alkali salt phase diagram, when the concentration of sodium hydroxide is 10%, the solubility of sodium chloride is about 65% of that of pure water solution; when the concentration of sodium hydroxide is 20%, the solubility of sodium chloride is about 40% of that of a pure aqueous solution thereof. During the reaction of the volatile gas and the alkali solution, the product is various alkali salts mainly comprising sodium chloride, wherein the sodium chloride can be crystallized in the alkali solution in a large amount, and simultaneously, part of sodium sulfate can be crystallized along with the sodium chloride. Since the solubility of sodium chlorate is high and the content of sodium chlorate in the solution is low, sodium chlorate does not crystallize with sodium chloride.

The alkali liquor preparation subsystem mainly comprises an alkali liquor preparation tank 210, a reaction precipitation kettle 212 and a first mother liquor tank 208, wherein the precipitation crystallization kettle 206 is provided with an alkali liquor inlet, a crystallized salt liquor outlet and a dilute salt liquor outlet, the alkali liquor inlet of the precipitation crystallization kettle 206 is connected with the alkali liquor outlet of the spray tower 201, the crystallized salt liquor outlet is connected with a first filtering centrifuge 207, the crystallized salt liquor formed at the bottom of the precipitation crystallization kettle 206 enters the first filtering centrifuge 207 to be subjected to first crystallization separation to form solid crystallized salt, and the solid crystallized salt is sent to the brine refining system 30; the first mother liquor tank 208 is provided with a first dilute brine inlet, a second dilute brine inlet connected with the first filtering centrifuge 207 and a dilute brine outlet, dilute brine separated by primary crystallization enters the first mother liquor tank 208 from the second dilute brine inlet of the first mother liquor tank 208, and the dilute brine outlet of the precipitation crystallization kettle 206 is connected with the first dilute brine inlet of the first mother liquor tank 208; the reaction and precipitation kettle 212 is provided with a dilute salt solution inlet, a feed inlet for adding a precipitator and a precipitate solution outlet, the dilute salt solution outlet of the first mother solution tank 208 is connected with the dilute salt solution inlet of the reaction and precipitation kettle 212 through a dilute salt solution conveying pipeline 214, and the precipitate solution outlet is connected with the brine refining system 30; the alkali liquor preparation tank 210 is provided with a feed inlet for adding solid sodium hydroxide, a first dilute saline solution inlet, a water adding port and an alkali liquor outlet, wherein the first dilute saline solution inlet is connected to the dilute saline solution conveying pipeline 214 and is used for guiding the dilute saline solution in the first mother liquor tank 208 into the alkali liquor preparation tank 210; the lye outlet of the lye preparation tank 210 is connected to the lye inlet of the scrubber 202.

The solid sodium hydroxide purchased from the market is lifted to the top of the alkali liquor preparation tank 210 by the electric hoist, and is put into the alkali liquor preparation tank 210 through the feed inlet of the alkali liquor preparation tank 210. The dilute brine from the crystallized brine circulating pump 209 enters the lye preparation tank 210 through a first dilute brine inlet of the lye preparation tank 210. The filter pressing water from the brine refining system 30 enters the alkali liquor preparation tank 210 through the water filling port of the alkali liquor preparation tank 210. The dilute brine from the evaporative crystallization system 40 enters the lye preparation tank 210 through the second dilute brine inlet of the lye preparation tank 210. If the liquid level of the lye preparation tank 210 is low, a part of the process water can be replenished from the water filling port. The solid sodium hydroxide is rapidly dissolved in the liquid under the stirring of the stirring device in the tank to form a sodium hydroxide solution. The adding amount of the solid sodium hydroxide is determined by the daily use condition of the waste gas washing system and the detection result of the dilute salt solution.

The prepared sodium hydroxide solution is pumped into a washing device in the washing tower by an alkali liquor feed pump 211 through an alkali liquor inlet of the washing tower 202, and is added into an alkali liquor circulation process of the washing tower 202 to wash and purify the volatile gas. The circulation pump 205 of the washing tower pumps part of the alkali liquor to the spray tower 201 in combination with the fresh amount of the alkali liquor provided by the alkali liquor feed pump 211 under the condition of ensuring the circulation usage amount of the alkali liquor in the washing tower 202, and the part of the alkali liquor enters the spraying device in the spray tower through the alkali liquor inlet of the spray tower 201, is added into the alkali liquor circulation process of the spray tower 201, and is sprayed in the spray tower, so that the temperature of the volatile gas is rapidly reduced. Under the condition of ensuring the circulating usage amount of the alkali liquor in the spray tower 201, the spray tower circulating pump 204 combines the amount of the alkali liquor provided by the washing tower circulating pump 205 to pump part of the alkali liquor to the precipitation crystallization kettle 206, and the part of the alkali liquor enters the precipitation crystallization kettle 206 through the alkali liquor inlet of the precipitation crystallization kettle 206. During the process of washing the volatile gas with the alkali liquor, a large amount of sodium chloride is generated, and the phenomenon of sodium chloride supersaturation is generated. Under the action of supersaturation, sodium chloride precipitates a large number of crystal nuclei, and these crystal nuclei enter the precipitation crystallization kettle 206 along with the alkali liquor. Meanwhile, the heavy metal in the volatile gas reacts with sodium hydroxide to generate heavy metal hydroxide precipitates, and the precipitates enter the precipitation crystallization kettle 206 along with the alkali liquor.

The precipitation crystallization kettle 206 is provided with a slow stirring device, and sodium chloride crystal nuclei further grow under the slow stirring of the stirring device to form sodium chloride crystal precipitates. Under the action of supersaturation degree, sodium chloride can be heterogeneously crystallized by means of interface of heavy metal hydroxide precipitate to form sodium chloride heterogeneously crystallized precipitate. If the concentration of sodium sulfate in the solution is high, a sodium sulfate crystal precipitate is also precipitated. The fully crystallized solution forms a dilute brine which overflows the dilute brine outlet of the precipitation crystallization kettle 206 and flows into the first mother liquor tank 208. The crystallized salt solution circulating pump 209 pumps the dilute salt solution out of the first mother liquor tank 208, and the dilute salt solution is sent into the alkali solution preparation tank 210 through a first dilute salt solution inlet of the alkali solution preparation tank 210 to be used for preparing a sodium hydroxide solution, so that the dilute salt solution is recycled.

When the total content of various crystallization precipitates (sodium chloride crystal precipitates, sodium chloride heterogeneous crystallization precipitates, heavy metal hydroxide precipitates and the like) in the precipitation crystallization kettle 206 reaches the separation concentration range required by the first filtering centrifuge 207, the first filtering centrifuge is started, and the crystallized salt solution at the bottom of the precipitation crystallization kettle is led into the first filtering centrifuge 207 through the crystallized salt solution outlet of the precipitation crystallization kettle 206. The crystallized salt solution from the precipitation crystallization kettle 206 enters a first filter centrifuge 207 for solid-liquid separation. The separated liquid is led into a first mother liquid tank 208 to form a dilute salt solution, and then is sent into an alkali liquor preparation tank 210 by a crystallized salt solution circulating pump 209 to be used for preparing a sodium hydroxide solution. The separated solid crystalline salt is discharged from the first filter centrifuge 207, collected and sent to the brine refining system 30 for further disposal.

During the process of washing the volatile gas with alkali liquor, a small amount of sodium chlorate is generated. Sodium chlorate is present in relatively small amounts and has a high solubility, and generally does not crystallize with sodium chloride. However, as the solution is continuously circulated through the flue gas scrubbing system 20, the sodium chlorate content will be higher and higher, with the potential for crystallization. In addition, the solution may also contain trace amounts of soluble salts with high solubility, such as fluoride salts and heavy metal complex salts, and the content of the soluble salts is higher and higher in the circulation process of the solution, so that the crystallization possibility exists.

After the solution circulates in the exhaust gas washing system 20 for a period of time, a part of the dilute salt solution is injected into the reaction precipitation kettle 212 from the dilute salt solution inlet of the reaction precipitation kettle 212 by the crystallized salt solution circulating pump 209. After the solution in the reaction precipitation kettle 212 reaches a certain liquid level, the injection is stopped. Various precipitants required by the precipitation reaction are added from a feed inlet of the reaction precipitation kettle 212. Firstly, adding a proper amount of hydrochloric acid, and adjusting the pH value of the solution to make the solution acidic; then adding sodium sulfite, ferrous chloride, barium chloride, flocculating agent and other precipitation reactants in sequence, finally adding a proper amount of sodium hydroxide, and adjusting the pH value of the solution to make the solution alkalescent. The reaction precipitation kettle 212 is provided with a stirring device, and each dosing stage needs to be fully stirred and fully reacted. The solution after the reaction forms a precipitation solution, and precipitates contained in the precipitation solution mainly comprise barium sulfate, barium fluoride and heavy metal hydroxide. The precipitated solution is directed to a brine refining system 30 for further disposal. The treated press filtration water is returned to the alkali liquor preparation tank 210 to be used for preparing the sodium hydroxide solution. The soluble salts with higher solubility are removed periodically, and the crystallization of the soluble salts in the solution circulation process can be effectively controlled. This is an intermittent operation, the frequency of which depends on the solubility of the various soluble salts and their concentration in the dilute salt solution.

The dosage of each kind of precipitant is determined by the laboratory according to the test result. The assay department carries out the timing assay to the dilute salt solution and issues written instructions according to the detection data. The production department adds various precipitants according to written instructions.

The solid crystalline salt produced by the flue gas scrubbing system 20 is primarily sodium chloride but contains a small amount of heavy metal hydroxides and is therefore still defined as a hazardous waste. The solid crystalline salt may also contain a certain amount of sulphate, depending on the sulphur content of the volatile gases and the actual operation of the flue gas scrubbing system 20 (circulation of lye). According to the regulations of Industrial salt (GB/T5462-2015), the primary industrial wet salt can contain not more than 0.7 percent of sulfate ions. Therefore, the small amount of sulfate contained in the solid crystalline salt does not affect the extraction thereof into industrial salt. If the content of the sulfate ions exceeds the national regulations, certain measures can be taken to remove the sulfate ions. The calcium and magnesium are not volatile, so that the calcium and magnesium elements entering the volatile gas are very little, and the calcium and magnesium content in the crystal salt is very little. According to the regulations of Industrial salt (GB/T5462-2015), the primary industrial wet salt can contain not more than 0.5 percent of calcium and magnesium ions. Therefore, the calcium and magnesium ions possibly existing in the solid crystalline salt have negligible influence on the industrial salt refining process. As known from the formation process of the solid crystalline salt, after the salt is volatilized at high temperature, the salt is absorbed by alkali liquor and is crystallized and separated, no organic matter is generated in the whole process, and therefore the solid crystalline salt does not contain the organic matter.

As shown in fig. 4, the brine refining system 30 includes a salt dissolving tank 301, a membrane filter 303, a primary brine tank 304, an ion exchange resin tower 306, a refined brine tank 307, a brine sludge liquid collecting tank 309, a plate-and-frame filter press 311, and a filter press water return tank 312, wherein the salt dissolving tank 301 has a water injection port, a feed port, a supernatant outlet, and a precipitate outlet, the feed port is used for inputting solid crystalline salt from the exhaust gas washing system 20 and adding a precipitating agent, the membrane filter 303 has a supernatant inlet, a primary brine outlet, and a filtrate outlet, the supernatant inlet is connected to the supernatant outlet of the salt dissolving tank 301, the primary brine outlet is connected to the primary brine tank 304, the ion exchange resin tower 306, and the refined brine tank 307 in sequence, and the refined brine tank 307 is connected to the evaporative crystallization system 40; salt mud liquid collection tank 309 has the precipitate entry, the filter entry, the precipitate entry, salt mud liquid export and supernatant export, the precipitate entry is connected with the precipitate exit of reation precipitation cauldron 212, the filter entry is connected with the filter exit of membrane filter 303, the precipitate entry is connected with the precipitate exit of salt melting tank 301, the supernatant export is connected with filter-pressing return water tank 312, plate and frame filter press 311 has salt mud liquid entry, pressure filtration liquid export and salt mud export, salt mud liquid entry and salt mud liquid exit linkage of salt mud liquid collection tank 309, the pressure filtration liquid export is connected with filter-pressing return water tank 312, the salt mud export is used for discharging the salt mud that the filter-pressing came out.

The condensed water from the evaporative crystallization system 40 is injected into the salt melting tank 301 from a water injection port of the salt melting tank 301. And stopping injecting after the condensed water in the salt dissolving tank 301 reaches a certain liquid level. When the condensed water is insufficient, the tap water is added for supplement. The solid crystallized salt from the waste gas scrubbing system 20 is fed into the salt melting tank 301 from a feed inlet of the salt melting tank 301. The salt dissolving tank 301 is provided with a stirring device, and under the stirring of the stirring device, the solid crystal salt is gradually dissolved in the condensed water to form brine. After the solid crystalline salt is fully dissolved, precipitating reactants such as barium chloride, flocculating agent and the like are sequentially added into brine in the salt dissolving tank 301 through a feeding port of the salt dissolving tank 301, and finally, a proper amount of sodium hydroxide is added to adjust the pH value of the solution to make the solution alkalescent. Sodium chloride in the solid crystalline salt is completely dissolved in brine, partial sulfate ions react with barium chloride to generate barium sulfate precipitate, and heavy metal hydroxide forms large-particle precipitate under the adsorption of a flocculating agent. And after all compounds in the brine are fully dissolved and fully reacted, stopping stirring, and allowing the precipitate to freely settle to the bottom of the tank. After the precipitate is fully deposited, the supernatant is pumped out by a salt dissolving water pump 302 through a supernatant outlet of the salt dissolving tank 301 and sent into a membrane filter 303. The supernatant outlet of the salt dissolving tank 301 comprises a plurality of liquid outlet points so as to empty the supernatant in the tank as much as possible. The sediment deposited at the bottom of the tank is guided into a salt slurry collecting tank 309 through a sediment outlet of the salt dissolving tank 301.

The amount of barium chloride added is strictly controlled to ensure that the barium salt added forms a barium sulfate precipitate so as not to stress the subsequent purification process. According to the solubility product principle of the insoluble electrolyte, the dissolution balance of the heavy metal hydroxide can be promoted to move leftwards by properly increasing the concentration of hydroxide ions, more precipitates are formed, and the content of heavy metals in the solution is reduced. However, it is not preferable to add too much sodium hydroxide because too high a hydroxide ion will react with the heavy metal hydroxide to form a complex, which is then dissolved again. Therefore, the pH of the solution needs to be strictly controlled, and is generally controlled to be 8 to 11. The dosage of the solid crystalline salt and the precipitating agent is determined by an assay department according to the assay result. And the assay department performs assay on the added substances such as the solid crystalline salt and the like and issues written instructions according to the detection data. The production department adds various materials according to written instructions.

The salt dissolving tank 301 adopts a three-tank combination: one tank is used for storing prepared brine and supplying liquid to the membrane filter; one tank is used for dissolving salt and preparing brine; a tank is provided for receiving the return condensate. The volume of the tank body is designed according to the amount of salt water needed by one shift.

The supernatant of the salt solution after free settling still contains a plurality of suspended matters which need to be further removed. The saltwater from the saltwater pump 302 enters the membrane filter 303 through the membrane filter 303 inlet. Suspended matters in the salt solution are blocked on the surface of the membrane by the filtering membrane to form a filtering matter. When the amount of the filtrate on the membrane surface reaches a certain amount, the negative pressure backwashing function is started, the filtrate is separated from the membrane surface under the backwashing action, is settled to the bottom of the membrane filter, is discharged out of the membrane filter through the filtrate outlet of the membrane filter 303, and is led into a salt mud liquid collecting tank 309. This is an intermittent operation, the frequency of which depends on the concentration of the suspension in the salt water. The filtrate passing through the filtration membrane forms a primary brine, which is discharged from the membrane filter through the primary brine outlet of the membrane filter 303 and introduced into the primary brine tank 304.

The membrane filter 303 may be a microfiltration membrane filter, an ultrafiltration membrane filter or a nanofiltration membrane filter, the filtration process of different types of membrane filters being slightly different.

According to the solubility product principle of the insoluble electrolyte, a certain amount of heavy metal ions may still exist in the primary brine. When these heavy metal ions exceed the relevant national standard requirements, the quality of the industrial salt is affected. The primary brine in the primary brine tank 304 is pumped into an ion exchange resin tower 306 through an inlet of the ion exchange resin tower 306 by a primary brine pump 305, and heavy metal ions possibly existing are adsorbed by the exchange resin. The brine from which the heavy metal ions are removed becomes refined brine, which is discharged from an outlet of the ion exchange resin tower 306 and introduced into a refined brine tank 307.

Because the components of the fly ash are complex, the content of the chlorofluorocarbon and volatile heavy metal components has high uncertainty, and therefore, the harmful components of the fly ash need to be detected before refined brine is sent to an evaporative crystallization system. If the detection is not qualified, the heavy metal ions are returned to the salt dissolving tank 301 for secondary precipitation, filtration and removal. The qualified refined brine is sent to the evaporative crystallization system 40 by the refined brine pump 308.

The ion exchange resin column 306 may be a two-column combination or a three-column combination, and the ion exchange process is slightly different in different combinations.

The refined brine tank 307 adopts a three-tank combination: a tank for holding the detected refined brine to supply liquid to the evaporative crystallization system 40; a tank for receiving the refined brine from the ion exchange resin column 306; one for standby. The volume of the tank body is designed according to the amount of refined brine required by one class.

The salt dissolving water and the precipitate from the salt dissolving tank 301 are introduced into the salt slurry collecting tank 309 through the precipitate inlet of the salt slurry collecting tank 309, the filtrate filtered by the membrane filter 303 is introduced into the salt slurry collecting tank 309 from the filtrate inlet of the salt slurry collecting tank 309, and the precipitate from the exhaust gas washing system 20 is introduced into the salt slurry collecting tank 309 through the precipitate inlet of the salt slurry collecting tank 309. The salt slurry collecting tank 309 is provided with a slow stirring device, and the stirring device slowly stirs to prevent salt from being adhered to the inner wall of the tank and crystallizing. After the salt slurry in the tank reaches a certain liquid level, the salt slurry pump 310 is started to pump out the salt slurry from the salt slurry outlet of the salt slurry collecting tank 309, and the salt slurry is sent to the plate-and-frame filter press 311. If the salt slurry liquid introduced from the three inlets has low salt slurry concentration and cannot meet the requirement of filter pressing, the salt slurry is allowed to freely settle for a period of time by stopping stirring, and then is sent into the filter press after the salt slurry concentration meets the requirement of filter pressing. The supernatant overflows to a filter-pressing water return tank 312 through a supernatant outlet of the salt slurry collecting tank 309.

The salt slurry pumped by the salt slurry pump 310 enters the plate-and-frame filter press 311 through the salt slurry inlet of the plate-and-frame filter press 311, and solid-liquid separation is realized in the plate-and-frame filter press. The separated pressure filtrate is guided into a pressure filtration water return tank 312 through a pressure filtrate outlet of the plate-and-frame filter press 311. The salt mud obtained by filter pressing is discharged out of the plate-and-frame filter press through a salt mud outlet of the plate-and-frame filter press 311, collected and transported to a factory for treatment outside the factory.

From the above treatment process, it is known that the composition of these salt sludges is mainly barium sulfate, doped with varying amounts of barium fluoride and heavy metal hydroxides. If the content of the heavy metal hydroxide meets the refining requirement, firstly, refining the heavy metal, and then, sending the refined salt mud to a barium salt refining process to recover barium element. And if the content of the heavy metal hydroxide does not meet the refining requirement, directly sending the salt slurry to a barium salt refining process to recover barium element. The salt slurry can also be sent to a cement plant for co-disposal or sent to a landfill for landfill.

The supernatant overflowing from the brine sludge collection tank 309 and the pressure-filtered liquid separated from the plate-and-frame filter press 311 are introduced into a filter-press water return tank 312, respectively. The press filtration water in the press filtration water return tank 312 is sent to the waste gas washing system 20 by the press filtration water return pump 313 to be prepared into alkali liquor, and is evaporated in the process of spraying and washing the volatile gas without being discharged.

As shown in fig. 5, the evaporative crystallization system 40 includes an evaporation subsystem, a condenser 408, an evaporative crystallization kettle 404, a condensed water tank 409, a second mother liquor tank 406 and a second filter centrifuge 405, wherein the evaporation subsystem may be a double-effect evaporation system, a triple-effect evaporation system or a four-effect evaporation system. Different evaporation systems have slightly different evaporation process flows. The evaporative crystallization system of the process is illustrated by taking a double-effect evaporative system as an example. The evaporation subsystem comprises at least two sets of evaporators with heaters and separators, namely a first-effect evaporator 401 and a second-effect evaporator 402, the heaters and the separators of the first-effect evaporator 401 and the second-effect evaporator 402 are connected to form a brine circulation loop in which brine circularly flows, wherein a pipeline connecting the bottoms of the heaters and the separators is a lower pipe section 412 of the circulation loop, the lower pipe sections 412 of the circulation loops of the first-effect evaporator 401 and the second-effect evaporator 402 are connected through a brine circulation connecting pipeline 413, the heater 401 of the first-effect evaporator is also provided with a refined brine inlet connected with a refined brine tank 307, a steam inlet used for inputting external steam and a condensate outlet, and the separator of the first-effect evaporator is also provided with a secondary steam outlet; the heater of the second-effect evaporator is also provided with a secondary steam inlet, a condensate outlet and a noncondensable gas outlet, the separator of the second-effect evaporator is also provided with a secondary steam outlet, a crystallized salt liquid outlet and a dilute salt liquid inlet, the condensate outlet of the heater of the first-effect evaporator is connected with a condensate water tank 409, the secondary steam outlet of the separator of the first-effect evaporator is connected with the secondary steam inlet of the heater of the second-effect evaporator, the condensate outlet of the heater of the second-effect evaporator is connected with the condensate water tank 409, the noncondensable gas outlet is connected with the steam inlet of a condenser 408, the secondary steam outlet of the separator of the second-effect evaporator is connected with the steam inlet of the condenser 408, the condensate outlet of the condenser is connected with the condensate water tank, the evaporative crystallization kettle 404 is provided with a crystallized salt liquid inlet, a dilute salt liquid outlet and a crystallized salt liquid outlet, the crystallized salt liquid outlet of the, the outlet of the dilute salt solution of the evaporative crystallization kettle 404 is connected with a second mother solution tank 406, the outlet of the crystallized salt solution of the evaporative crystallization kettle 404 is connected with a second filtering centrifuge 405, the crystallized salt solution is crystallized and separated for the second time by the second filtering centrifuge 405 to form solid industrial salt which is discharged, the separated dilute salt solution is introduced into the second mother solution tank 406, and the second mother solution tank 406 is connected with the dilute salt solution inlet of the second-effect evaporator separator to enable the dilute salt solution to flow back to the second-effect evaporator separator for evaporation and concentration again.

Refined brine from the brine refining system 30 enters the single-effect evaporator 401 from a refined brine inlet of the single-effect evaporator 401, joins with circulating brine pumped by a forced circulation pump of the single-effect evaporator 401, passes through a heater of the single-effect evaporator 401 from bottom to top, and exchanges heat with external steam in the heater. After the circulating brine of the single-effect evaporator absorbs the heat of the external steam, part of liquid water is changed into steam. The circulating brine after heat exchange enters a separator 401 of the one-effect evaporator, and steam is separated from the brine to form secondary steam. Under the action of the vacuum pump 411, a certain vacuum degree is formed in the separator, so that the separation of steam can be accelerated, and the amount of secondary steam can be increased. The secondary steam is discharged through a secondary steam outlet of the first-effect evaporator 401 and enters the second-effect evaporator 402. The separated circulating brine is continuously circulated, evaporated and concentrated under the action of a forced circulation pump. After the brine is concentrated to a certain concentration, a portion of the brine is introduced into dual effect evaporator 402 from circulating brine connection 413.

Low-pressure steam from the outside enters the first-effect evaporator 401 from a steam inlet of the first-effect evaporator 401, passes through a heater of the first-effect evaporator 401 from top to bottom, transfers heat to circulating brine, is condensed into water, is discharged from a condensed water outlet of the first-effect evaporator 401, and is guided into a condensed water tank 409.

Brine from the first-effect evaporator 401 enters the second-effect evaporator 402 through a circulating brine connecting pipeline 413, is merged with circulating brine of the second-effect evaporator 402, passes through a heater of the second-effect evaporator 402 from bottom to top under the action of a forced circulating pump of the second-effect evaporator 402, and exchanges heat with secondary steam in the heater. After the circulating brine of the double-effect evaporator absorbs the heat of the secondary steam, part of the liquid water is changed into steam. The circulating brine after heat exchange enters a separator of a double-effect evaporator 402, and steam is separated from the brine to form secondary steam again. Under the action of the vacuum pump 411, a certain vacuum degree is formed in the separator, so that the separation of steam can be accelerated, and the amount of secondary steam can be increased. The secondary steam exits through the secondary steam outlet of the secondary evaporator 402 and enters the condenser 408. The separated circulating brine is continuously circulated, evaporated and concentrated under the action of a forced circulation pump.

The secondary steam from the first-effect evaporator 401 enters the second-effect evaporator 402 from a secondary steam inlet of the second-effect evaporator 402, passes through a heater of the second-effect evaporator 402 from top to bottom, transfers heat to circulating brine, is condensed into water, is discharged through a condensed water outlet of the second-effect evaporator 402, and is guided into a condensed water tank 409. A small amount of non-condensable gas contained in the secondary steam is discharged through the non-condensable gas outlet of the double effect evaporator 402 and introduced into the condenser 408.

The brine after twice evaporation and concentration forms a large amount of sodium chloride crystal nuclei under the action of supersaturation. The sodium chloride nuclei settle to the bottom of the separator of the double effect evaporator 402 to form a crystallized salt solution. The crystallized salt liquid is discharged from a crystallized salt liquid outlet of the double-effect evaporator 402 and is pumped to an evaporation crystallization kettle 404 by a crystallized salt liquid discharge pump 403. The bottom of the separator of the double-effect evaporator of the evaporative crystallization system 40 is provided with a crystallized salt liquid inlet which is connected to a pipeline between the crystallized salt liquid outlet of the separator of the double-effect evaporator and the crystallized salt liquid inlet of the evaporative crystallization kettle, part of the crystallized salt liquid discharged from the crystallized salt liquid discharge pump 403 is injected into the separator of the double-effect evaporator 402 through the crystallized salt liquid inlet at the bottom of the separator of the double-effect evaporator 402, and the crystallized salt liquid at the bottom of the separator is stirred to prevent the crystal nucleus of sodium chloride from being adhered to the wall in the separator.

The other part of the crystallized salt solution from the crystallized salt solution discharge pump 403 is injected into the evaporative crystallization kettle 404 through the crystallized salt solution inlet of the evaporative crystallization kettle 404. The evaporative crystallization kettle 404 is provided with a slow stirring device, and sodium chloride crystal nuclei further grow under the slow stirring of the stirring device to form sodium chloride crystal precipitates. According to the preparation process of refined brine, the crystallized salt solution contains certain sodium hydroxide, and the concentration of the sodium hydroxide is higher and higher along with the evaporation of water. The sodium hydroxide with proper concentration can greatly reduce the solubility of the sodium chloride and promote the crystallization of the sodium chloride. The crystallized salt solution after full crystallization forms a dilute salt solution, which overflows from the dilute salt solution outlet of the evaporative crystallization kettle 404 and flows into the second mother liquor tank 406.

When the content of the sodium chloride crystal precipitate in the evaporation crystallization kettle 404 reaches the separation concentration range required by the second filtering centrifuge, the second filtering centrifuge 405 is started, and the crystallized salt liquid at the bottom of the evaporation crystallization kettle is led into the second filtering centrifuge 405 through the crystallized salt liquid outlet of the evaporation crystallization kettle 404 for solid-liquid separation. The separated liquid forms a weak brine which is directed to a second mother liquor tank 406. The separated solid industrial salt is discharged from the second filtering centrifuge 405, further dried, packaged and delivered according to the requirements of industrial salt (GB/T5462-2015) and sent to industrial salt application units for use.

The dilute salt solution in the second mother solution tank 406 is pumped out by a crystallized salt solution reflux pump 407, and is refluxed to the separator of the second effect evaporator 402 through the dilute salt solution inlet of the separator of the second effect evaporator 402, and is evaporated and concentrated again. Sodium hydroxide of appropriate concentration can promote sodium chloride crystallization, but when the concentration of sodium hydroxide is too high, sodium hydroxide crystallization can occur, thereby affecting the quality of industrial salt. Therefore, during the operation of the system, it is necessary to timely send a part of the dilute salt solution pumped by the crystallized salt solution reflux pump 407 to the exhaust gas scrubbing system 20 so as to maintain the sodium hydroxide concentration in the dilute salt solution within a certain range. The dilute salt solution sent to the waste gas washing system 20 participates in the circulation of alkali liquor of the waste gas washing system to wash the volatile gas.

The non-condensable gas and the secondary steam from the second-effect evaporator 402 enter the condenser 408, heat is transferred to cooling water in the condenser 408 through the pipe wall, the secondary steam is condensed into liquid water, and the liquid water is discharged out of the condenser 408 together with the non-condensable gas and guided into a condensed water tank 409. Circulating cooling water from an external circulating cooling water system enters the condenser 408, absorbs heat transferred by the non-condensable gas and the secondary steam, and then is discharged 408 out of the condenser and returns to the external circulating cooling water system.

The condensed water from the first-effect evaporator 401, the condensed water from the second-effect evaporator 402, the condensed water from the condenser 408, and the non-condensable gas are introduced into a condensed water tank 409, respectively. After being collected in the condensate tank 409, the condensate is pumped out by the condensate pump 410 and sent to the brine refining system 30 for preparing brine. The non-condensable gas in the condensed water tank 409 is pumped out by a vacuum pump 411, and the non-condensable gas comprises air and water vapor and can be directly evacuated.

The embodiments of the present invention are not limited to the above, according to the above-mentioned contents of the present invention, according to the common technical knowledge and the conventional means in the field, without departing from the basic technical idea of the present invention, the present invention can also make other modifications, replacements or changes in various forms, all falling within the scope of the present invention.

Claims (10)

1. An incineration fly ash disposal system is characterized in that: the fly ash and admixture combined type industrial salt production device comprises a fly ash melting system, a waste gas washing system, a brine refining system and an evaporative crystallization system which are connected in sequence, wherein a batch prepared from incineration fly ash and an admixture is put into the fly ash melting system, volatile gas is generated and forms slag after high-temperature melting, the volatile gas enters the waste gas washing system, is led into a chimney of a power plant for concentrated discharge after being treated by alkali liquor spraying and washing to reach the standard, a solid-liquid product after being sprayed and washed is precipitated and crystallized to form crystallized salt liquid, solid crystallized salt is prepared through primary crystallization and separation, and then enters the brine refining system to prepare brine, and then enters the evaporative crystallization system, and industrial salt is prepared through evaporative crystallization and secondary crystallization and separation.

2. The incineration fly ash disposal system according to claim 1, characterized in that: the fly ash melting system comprises a high-temperature melting furnace and a feeding subsystem used for conveying batch materials to the high-temperature melting furnace, the high-temperature melting furnace is an all-electric melting furnace with a cold roof structure, the inner space of the high-temperature melting furnace comprises a melting chamber used for melting high-temperature melt and a material channel purifying chamber used for preparing the high-temperature melt, the material channel purifying chamber is provided with a dust settling structure, the melting chamber is communicated with the material channel purifying chamber through a liquid flow hole and an ascending material channel, the material channel purifying chamber is provided with a slag outlet used for discharging slag and a volatile gas outlet used for discharging volatile gas, and the slag outlet is lower than the liquid level of the high-temperature melt so that the high-temperature melt sequentially passes through the liquid flow hole and the ascending material channel to form homogenized melt which flows into the material channel purifying chamber; the top surfaces of the melting chamber and the material channel purifying chamber are provided with air guide flues communicated with the melting chamber and the material channel purifying chamber, the homogenized melt in the material channel purifying chamber meets volatile gas from the air guide flues, partial heat is transferred to the volatile gas, and dust settled from the volatile gas is absorbed and melted.

3. The incineration fly ash disposal system according to claim 2, characterized in that: the feeding subsystem includes blending feed bin, flying ash storehouse, the mixed conveying mechanism that weighs, batch buffer bin and rotary feeder, the mixed conveying mechanism that weighs is located the below of blending feed bin and flying ash storehouse for weigh respectively admixture and burn the flying ash and prepare into the batch and carry to batch buffer bin, rotary feeder has feed end and feed end, the feed end is located the below of batch buffer bin, is used for receiving the batch, the feed end stretches into fan-shaped rotary motion is done to the top of high temperature fuse-element in the melting chamber to lay the batch evenly on the liquid level of high temperature fuse-element.

4. The incineration fly ash disposal system according to claim 3, wherein: the waste gas washing system comprises a spray tower, a washing tower, a precipitation crystallization kettle, a first filtering centrifuge and an alkali liquor preparation subsystem, wherein the spray tower is provided with a volatile gas inlet, an alkali liquor outlet and a volatile gas outlet, the volatile gas from the fly ash melting system enters the spray tower, the washing tower is provided with a volatile gas inlet, a volatile gas outlet, an alkali liquor inlet and an alkali liquor outlet, the volatile gas outlet of the spray tower is connected with the volatile gas inlet of the washing tower, and the washed and purified volatile gas is sent to a chimney of a power plant to be discharged; the alkali liquor inlet of the spray tower is connected with the alkali liquor inlet of the washing tower through a circulating alkali liquor pipeline, and the alkali liquor outlet of the spray tower is connected with the circulating alkali liquor pipeline so as to guide the alkali liquor at the bottom of the spray tower into the spray tower to realize the circulation of the alkali liquor in the spray tower; the alkali liquor outlet of the washing tower is connected with a circulating alkali liquor pipeline so as to guide the alkali liquor at the bottom of the washing tower into the washing tower to realize circulation of the alkali liquor in the washing tower; the precipitation crystallization kettle is provided with an alkali liquor inlet, a crystallized salt liquid outlet and a dilute salt liquid outlet, the alkali liquor inlet of the precipitation crystallization kettle is connected with the alkali liquor outlet of the spray tower, the crystallized salt liquid outlet is connected with a first filtering centrifugal machine, the dilute salt liquid outlet is connected with the alkali liquor preparation subsystem, the crystallized salt liquid formed at the bottom of the precipitation crystallization kettle enters the first filtering centrifugal machine to be crystallized and separated for the first time to form solid-state crystallized salt, the solid-state crystallized salt is sent to the brine refining system, the separated dilute salt liquid enters the alkali liquor preparation subsystem, and the alkali liquor inlet of the washing tower is connected with the alkali liquor preparation subsystem.

5. The incineration fly ash disposal system according to claim 4, wherein: the alkali liquor preparation subsystem mainly comprises an alkali liquor preparation tank, a reaction precipitation kettle and a first mother liquor box, wherein the first mother liquor box is provided with a first dilute salt liquor inlet connected with the precipitation crystallization kettle, a second dilute salt liquor inlet connected with the first filtering centrifuge and a dilute salt liquor outlet, the reaction precipitation kettle is provided with a dilute salt liquor inlet, a feed inlet used for adding a precipitator and a precipitation liquor outlet, the dilute salt liquor outlet of the first mother liquor box is connected with the dilute salt liquor inlet of the reaction precipitation kettle through a dilute salt liquor conveying pipeline, and the precipitation liquor outlet is connected with the brine refining system; the alkali liquor preparation tank is provided with a feed inlet for adding solid sodium hydroxide, a first dilute salt solution inlet, a water adding port and an alkali liquor outlet, and the first dilute salt solution inlet is connected to a dilute salt solution conveying pipeline and is used for guiding the dilute salt solution of the first mother liquor tank into the alkali liquor preparation tank; and an alkali liquor outlet of the alkali liquor preparation tank is connected with an alkali liquor inlet of the washing tower.

6. The incineration fly ash disposal system according to claim 5, wherein: the brine refining system comprises a salt dissolving tank, a membrane filter, a primary brine tank, an ion exchange resin tower, a refined brine tank, a brine mud liquid collecting tank, a plate-and-frame filter press and a filter pressing water return tank, wherein the salt dissolving tank is provided with a water injection port, a feed port, a supernatant outlet and a precipitate outlet, the feed port is used for inputting solid crystalline salt from an exhaust gas washing system and adding a precipitating agent, the membrane filter is provided with a supernatant inlet, a primary brine outlet and a filtrate outlet, the supernatant inlet is connected with the supernatant outlet of the salt dissolving tank, the primary brine outlet is connected with the primary brine tank, the brine ion exchange resin tower and the refined brine tank in sequence, and the refined brine tank is connected with the evaporation and crystallization system; salt mud liquid collection tank has deposit entry, filtering material entry, precipitation liquid entry, salt mud liquid export and supernatant export, the precipitation liquid entry with reation precipitation cauldron's precipitation liquid exit linkage, the filtering material entry with membrane filter's filtering material exit linkage, the deposit entry with change salt tank's deposit exit linkage, the supernatant export with filter-pressing return water tank connects, the plate and frame pressure filter has salt mud liquid entry, pressure filtrate export and salt mud export, salt mud liquid entry with salt mud liquid exit linkage of salt mud liquid collection tank, pressure filtrate export with filter-pressing return water tank connects, the salt mud export is used for discharging the salt mud that the filter-pressing came out.

7. The incineration fly ash disposal system according to claim 6, wherein: the evaporation crystallization system comprises an evaporation subsystem, an evaporation crystallization kettle and a second filtering centrifuge, the evaporation subsystem comprises at least two sets of evaporators with heaters and separators, the heaters and the separators of each set of evaporators are connected to form a brine circulation loop with brine circulation flowing, the brine circulation loops of the evaporators are connected through brine circulation connecting pipelines, the separators of the evaporators before the last evaporator are connected with the heaters of the adjacent evaporators at the rear parts of the evaporators through secondary steam outlets, the heaters of the evaporators are provided with condensate water outlets, the heater of the first evaporator is also provided with a refined brine inlet connected with a refined brine tank and a steam inlet used for inputting external steam, the heaters of the evaporators after the first evaporator are also provided with non-condensable gas outlets, the separator of the last evaporator is also provided with a secondary steam outlet and a crystallized salt liquid outlet used for discharging the secondary steam, the evaporative crystallization kettle is provided with a crystallized salt liquid inlet, a dilute salt liquid outlet and a crystallized salt liquid outlet, the crystallized salt liquid outlet of the final evaporator is connected with the crystallized salt liquid inlet of the evaporative crystallization kettle, the crystallized salt liquid outlet of the evaporative crystallization kettle is connected with the second filtering centrifuge, and the crystallized salt liquid is subjected to secondary crystallization separation by the second filtering centrifuge to form solid industrial salt to be discharged.

8. The incineration fly ash disposal system according to claim 7, wherein: the evaporative crystallization system further comprises a condenser, a condensate water tank and a second mother liquor tank, wherein a condensate water outlet of each evaporator is connected with the condensate water tank, a non-condensable gas outlet of each evaporator and a secondary steam outlet of a last evaporator are respectively connected with a steam inlet of the condenser, and a condensate water outlet of the condenser is connected with the condensate water tank; and a dilute salt solution outlet of the evaporative crystallization kettle is connected with a second mother solution tank, dilute salt solution separated by a second filtering centrifuge is introduced into the second mother solution tank, and the separator of the last evaporator is also provided with a dilute salt solution inlet which is connected with a dilute salt solution outlet of the second mother solution tank, so that the dilute salt solution flows back to the separator of the last evaporator and is evaporated and concentrated again.

9. The incineration fly ash disposal system according to claim 8, wherein: the bottom of the last evaporator separator of the evaporative crystallization system is also provided with a crystallized salt liquid inlet which is connected on a pipeline between a crystallized salt liquid outlet of the last evaporator and a crystallized salt liquid inlet of the evaporative crystallization kettle.

10. The incineration fly ash disposal system according to claim 9, wherein: the alkali liquor preparation tank is also provided with a second dilute brine inlet, and a second mother liquor box of the evaporative crystallization system is connected with the second dilute brine inlet of the alkali liquor preparation tank; the filter pressing water return tank is connected with a water filling port of the alkali liquor preparation tank and is used for guiding filter pressing water and connecting process water from the outside; and a water injection port of the salt melting tank is connected with the condensed water tank and is used for inputting condensed water and can be accessed into tap water from the outside.

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