阅读说明：本技术 一种生活垃圾焚烧飞灰水洗脱盐系统及方法 (System and method for eluting household garbage incineration fly ash with water ) 是由 雷仲波 王卫民 吴忠勇 谢庚 王山 孙毅晨 陶应翔 于 2021-01-27 设计创作，主要内容包括：本发明公开的一种生活垃圾焚烧飞灰水洗脱盐系统,包括有飞灰洗涤系统、过滤系统及洗饼系统。该系统能够达到给飞灰脱盐的目的,减少对烟气处理设备的腐蚀。还提供了一种生活垃圾焚烧飞灰水洗脱盐方法,具体为：第一步：飞灰洗涤配浆；第二步：过滤；第三步：一次洗涤；第四步：二次洗涤；第五步：卸料。该方法分别采用一次洗涤水、二次洗涤水和冷凝水对飞灰和滤饼进行洗涤,洗涤水盐分浓度由高质到低,既达到了飞灰脱盐的目的,又最大程度减少了冷凝水的用量,降低了系统高盐水的排放,减轻了后续三效蒸发装置的处理量。(The invention discloses a household garbage incineration fly ash water desalting system which comprises a fly ash washing system, a filtering system and a cake washing system. The system can achieve the aim of desalting fly ash and reduce the corrosion to flue gas treatment equipment. Also provides a washing and desalting method of the household garbage incineration fly ash, which comprises the following steps: the first step is as follows: washing fly ash and preparing slurry; the second step is that: filtering; the third step: washing for the first time; the fourth step: washing for the second time; the fifth step: and (6) discharging. The method adopts the primary washing water, the secondary washing water and the condensed water to wash the fly ash and the filter cake respectively, the salt concentration of the washing water is from high quality to low, the aim of fly ash desalination is achieved, the consumption of the condensed water is reduced to the maximum extent, the discharge of high-salt water of the system is reduced, and the treatment capacity of a follow-up triple-effect evaporation device is reduced.)

1. A household garbage incineration fly ash water desalination system is characterized by comprising a fly ash washing system, a filtering system and a cake washing system;

the fly ash washing system comprises a slurry tank (5), a slurry stirrer (4) is arranged at the top of the slurry tank (5), a weighing screw (3) is arranged above the top of the slurry tank (5), and a discharge hole of the weighing screw (3) is communicated with the top of the slurry tank (5); a slurry outlet is formed in the side wall of the slurry tank (5), the slurry outlet is connected with a slurry pump (6) through a first pipeline (31), and a discharge hole of the slurry pump (6) is connected with a second pipeline (32);

the filtering system comprises a slurry filtrate pump (1), a discharge hole of the slurry filtrate pump (1) is connected with the triple-effect evaporation device through a seventh pipeline (37), a feed inlet of the slurry filtrate pump (1) is connected with a slurry filtrate tank (2) through a sixth pipeline (36), and a feed inlet of a top filling of the slurry filtrate tank (2) is connected with a fifth pipeline (35); the device is characterized by also comprising a plate and frame filter (13), wherein a blow-drying opening (18) of the plate and frame filter (13) is connected with a compressed air storage tank through a ninth pipeline (39), a high-pressure water port (14) of the plate and frame filter (13) is connected with a high-pressure water station through an eighth pipeline (38), a filtrate outlet (47) of the plate and frame filter (13) is communicated with a top filling of a slurry tank (5) through a fifteenth pipeline (45), a water inlet (49) of the plate and frame filter (13) is connected with a fourteenth pipeline (44), and a fifth pipeline (35) is communicated with the fifteenth pipeline (45); the second pipeline (32) is communicated with the fourteenth pipeline (44);

the cake washing system comprises a primary washing tank (7), the top of the primary washing tank (7) is communicated with a fifteenth pipeline (45) through a third pipeline (33), the side wall of the primary washing tank (7) is connected with a primary washing pump (8) through a tenth pipeline (40), and the discharge hole of the primary washing pump (8) is communicated with a fourteenth pipeline (44) through an eleventh pipeline (41); the device is characterized by also comprising a secondary washing tank (12), wherein the top of the secondary washing tank (12) is connected with a triple-effect evaporation device through a sixteenth pipeline (46), the side wall of the secondary washing tank (12) is connected with a secondary washing pump (10) through a twelfth pipeline (42), and a discharge hole of the secondary washing pump (10) is communicated with a fourteenth pipeline (44) through a thirteenth pipeline (43);

a primary washing flowmeter (9) is arranged on the eleventh pipeline (41); and a secondary washing flow meter (11) is arranged on the thirteenth pipeline (43).

2. The household garbage incineration fly ash water desalination system according to claim 1, characterized in that a fifth valve (23) is arranged on the eleventh pipeline (41), and the fifth valve (23) is positioned between the primary washing flow meter (9) and the discharge port of the primary washing pump (8); and a sixth valve (24) is arranged on the thirteenth pipeline (43), and the sixth valve (24) is positioned between the secondary washing flow meter (11) and the discharge hole of the secondary washing pump (10).

3. The household garbage incineration fly ash water desalination system as claimed in claim 1, wherein a sewage discharge outlet (48) of the plate and frame filter (13) is communicated with the top of the slurry tank (5) through a fourth pipeline (34), and a third valve (21) is arranged on the fourth pipeline (34).

4. The system for washing and desalting fly ash from incineration of household garbage according to claim 1, wherein a twelfth valve (30) is arranged on the ninth pipeline (39); an eleventh valve (29) is arranged on the eighth pipeline (38); a primary washing water discharge valve (16) is arranged on the fifteenth pipeline (45); a filtrate discharge valve (15) is arranged on the fifth pipeline (35); a secondary washing water discharge valve (17) is arranged on the third pipeline (33); a ninth valve (27) is arranged on the sixth pipeline (36); a tenth valve (28) is arranged on the seventh pipeline (37); a first valve (19) is arranged on the first pipeline (31); a second valve (20) is arranged on the second pipeline (32); an eighth valve (26) is arranged on the sixteenth pipeline (46); a fourth valve (22) is arranged on the tenth pipeline (40); and a seventh valve (25) is arranged on the twelfth pipeline (42).

5. A method for washing and desalting fly ash generated by burning household garbage by water, which adopts the system as claimed in any one of claims 1 to 4, and is characterized by comprising the following steps:

the first step is as follows: fly ash washing slurry

Starting a slurry stirrer (4), conveying the fly ash with the mass of 1/3 primary washing water to a slurry tank (5) by using a weighing screw (3) according to the metering value of a primary washing flowmeter (9) in the last washing period, and fully and uniformly mixing the fly ash with the primary washing water to prepare slurry;

the second step is that: filtration

The plate and frame filter (13) is ready, the slurry pump (6) is started, slurry is conveyed to the plate and frame filter (13) for pre-filtration, the filtrate discharge valve (15) is opened at the same time, and the slurry pump (6) is stopped after the pre-filtration is finished; then starting a high-pressure water station, enabling high-pressure water to enter a plate and frame filter (13) from a high-pressure water gap (14) to squeeze filter cakes, and stopping the high-pressure water station after the compaction is finished for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter (13) from a blow-drying opening (18) to blow-dry a filter cake; the filtrate generated in the filtering process enters a slurry filtrate tank (2) and is conveyed to a triple-effect evaporation device by using a slurry filtrate pump (1);

the third step: one-time washing

Starting a primary washing pump (8) to enable secondary washing water in the primary washing tank (7) to enter a filter cake in a cavity of the plate and frame filter (13) to wash the filter cake; simultaneously closing a filtrate discharge valve (15), opening a primary washing water discharge valve (16), and enabling generated primary washing water to enter a slurry tank (5), wherein the using amount of the washing water is the same as the metering value of a primary washing flowmeter (9) in the last washing period; after the filter cake is washed, stopping the primary washing pump (8), and then squeezing and drying the filter cake;

the fourth step: second washing

Starting a secondary washing pump (10) to enable condensed water in a secondary washing tank (12) to enter a filter cake in a cavity of a plate and frame filter (13), and washing the filter cake; simultaneously closing a primary washing water discharge valve (16), opening a secondary washing water discharge valve (17), and enabling the generated secondary washing water to enter a primary washing tank (7), wherein the using amount of the washing water is the same as the metering value of a primary washing flowmeter (9) in the last washing period; after the filter cake is washed, stopping the secondary washing pump (10), and then squeezing and drying the filter cake;

the fifth step: discharging

And opening the full-automatic plate and frame filter (13), unloading the filter cake, cleaning the filter cloth, and preparing the plate and frame filter (13) to enter the next working cycle after the filter cloth is cleaned.

6. The method for washing and desalting the fly ash generated by burning the household garbage according to claim 5, wherein the concrete procedures of pressing and drying the filter cake in the third step and the fourth step are as follows: starting a high-pressure water station, enabling high-pressure water to enter a plate and frame filter (13) from a high-pressure water gap (14) to squeeze filter cakes, and stopping the high-pressure water station after compaction is completed for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter (13) from a blow-drying opening (18) to blow-dry the filter cake.

Technical Field

The invention belongs to the technical field of household garbage incineration equipment, and particularly relates to a household garbage incineration fly ash water desalting system and a household garbage incineration fly ash water desalting method.

Background

The process for treating the fly ash burned by the household garbage at high temperature by using the plasma generates high-temperature gas by using a plasma generator, the fly ash is melted by adding a mixture of a certain proportion of a melting aid in a melting furnace, then the melt is quenched by water to form a glassy substance, and the glassy substance meets the requirements on indexes of the glassy body and the standard requirements on the resource utilization of the glassy body in the specifications of technical requirements on vitrified products of solid wastes and technical specifications on pollution control of fly ash burned by the household garbage (the comments are made).

When the fly ash generated by burning the household garbage is treated by the high-temperature melting of the plasma, chlorine salts such as sodium chloride and potassium chloride volatilize at high temperature and generate a large amount of hydrogen chloride gas with water, and the chlorine salts and the hydrogen chloride in the flue gas seriously corrode a flue at the outlet of a secondary combustion chamber, flue gas treatment system equipment, pipelines and the like. In order to solve the problem of flue gas corrosion and equipment corrosion, a water-washing fly ash system is added in a pretreatment unit in the process of treating the household garbage incineration fly ash by plasma high-temperature melting to remove chlorine salts such as sodium chloride and potassium chloride in the fly ash, so that the content of 30% of the chlorine salts in the fly ash after water washing is reduced to below 1%.

At present, the technology of utilizing the waste incineration fly ash water elution salt (FWD) and the cement kiln to cooperatively treat is to firstly carry out water elution salt on fly ash to reduce the chlorine content in the fly ash to be less than 1 percent and then utilize the cement kiln to cooperatively treat. The cement kiln co-processing fly ash washing system has the main function of separating potassium, sodium, sulfur and chlorine plasma in fly ash from fly ash through a washing process so as to meet the requirement of putting fly ash into a kiln. The system adopts a counter-current rinsing technology, after fly ash slurry is subjected to solid-liquid separation by a first-stage elution reactor and an elution separator, the elution ash enters a next-stage elution reactor for secondary washing, and the eluent enters a water quality purification treatment system. The washing times and the water consumption are determined according to the detection result of the chlorine content in the fly ash. In general, the secondary water washing can effectively remove chloride ions in the fly ash, and in order to ensure the treatment effect of the fly ash elution system, the third elution is carried out, so that the effective removal rate of the chloride ions is ensured to be more than 95%. And (3) storing the elution ash subjected to the third elution separation, wherein the chlorine content is controlled within 1%, sending the stored elution ash to a cement enterprise for wet ash drying treatment, and entering a cement kiln for high-temperature calcination to generate cement clinker.

At present, three-stage countercurrent rinsing is adopted for washing and desalting fly ash in a process of cooperatively treating the fly ash by a cement kiln, a core device for washing and desalting is a horizontal screw centrifuge, the process needs 3 centrifuges to operate in series, the equipment and an accessory pipeline have high investment cost once, the operation cost is high, the operation and maintenance are complex, and the operation and maintenance cost is high. By consulting the parameters of the horizontal decanter centrifuge, the minimum treatment capacity of fly ash is 25t/d, and the method is suitable for large-scale industrial application occasions. In addition, the water content of mud cakes of the horizontal screw centrifuge is about 50 percent, the water content is higher, and the energy consumption of the post-treatment drying process of the mud cakes is increased.

Disclosure of Invention

The invention aims to provide a domestic garbage incineration fly ash water desalination system, which can achieve the aim of desalinating fly ash and reduce the corrosion to flue gas treatment equipment.

The second purpose of the invention is to provide a method for desalting the fly ash generated by burning the household garbage by washing.

The invention adopts the technical scheme that a household garbage incineration fly ash water desalting system comprises a fly ash washing system, a filtering system and a cake washing system;

the fly ash washing system comprises a slurry tank, a slurry stirrer is arranged at the top of the slurry tank, a weighing screw is arranged above the top of the slurry tank, and a discharge port of the weighing screw is communicated with the top of the slurry tank; a slurry outlet is formed in the side wall of the slurry tank, the slurry outlet is connected with a slurry pump through a first pipeline, and a discharge port of the slurry pump is connected with a second pipeline;

the filtering system comprises a slurry filtrate pump, a discharge hole of the slurry filtrate pump is connected with the triple-effect evaporation device through a seventh pipeline, a feed hole of the slurry filtrate pump is connected with a slurry filtrate tank through a sixth pipeline, and a feed hole of a top filling of the slurry filtrate tank is connected with a fifth pipeline; the device also comprises a plate and frame filter, wherein a blow-drying opening of the plate and frame filter is connected with a compressed air storage tank through a ninth pipeline, a high-pressure water opening of the plate and frame filter is connected with a high-pressure water station through an eighth pipeline, a filtrate outlet of the plate and frame filter is communicated with a slurry tank through a fifteenth pipeline, a water inlet of the plate and frame filter is connected with a fourteenth pipeline, and a fifth pipeline is communicated with the fifteenth pipeline; the second pipeline is communicated with the fourteenth pipeline;

the cake washing system comprises a primary washing tank, the top of the primary washing tank is communicated with a fifteenth pipeline through a third pipeline, the side wall of the primary washing tank is connected with a primary washing pump through a tenth pipeline, and a discharge hole of the primary washing pump is communicated with a fourteenth pipeline through an eleventh pipeline; the device also comprises a secondary washing tank, the top of the secondary washing tank is connected with the triple-effect evaporation device through a sixteenth pipeline, the side wall of the secondary washing tank is connected with a secondary washing pump through a twelfth pipeline, and a discharge hole of the secondary washing pump is communicated with the fourteenth pipeline through a thirteenth pipeline;

a primary washing flowmeter is arranged on the eleventh pipeline; and a secondary washing flowmeter is arranged on the thirteenth pipeline.

The present invention is also characterized in that,

a fifth valve is arranged on the eleventh pipeline and is positioned between the primary washing flowmeter and the discharge hole of the primary washing pump; and a sixth valve is arranged on the thirteenth pipeline and is positioned between the secondary washing flowmeter and the discharge hole of the secondary washing pump.

And a sewage discharge outlet of the plate and frame filter is communicated with the top of the slurry tank through a fourth pipeline, and a third valve is arranged on the fourth pipeline.

A twelfth valve is arranged on the ninth pipeline; an eleventh valve is arranged on the eighth pipeline; a first washing water discharge valve is arranged on the fifteenth pipeline; a filtrate discharge valve is arranged on the fifth pipeline; a secondary washing water discharge valve is arranged on the third pipeline; a ninth valve is arranged on the sixth pipeline; a tenth valve is arranged on the seventh pipeline; the first pipeline is provided with a first valve; a second valve is arranged on the second pipeline; an eighth valve is arranged on the sixteenth pipeline; a fourth valve is arranged on the tenth pipeline; a seventh valve is arranged on the twelfth pipeline.

The second technical scheme adopted by the invention is that the method for desalting the incineration fly ash of the household garbage by washing comprises the following steps of:

the first step is as follows: fly ash washing slurry

Starting a slurry stirrer, conveying the fly ash with the mass of 1/3 primary washing water to a slurry tank by using a weighing screw according to the metering value of a primary washing flowmeter in the last washing period, and fully and uniformly mixing the fly ash with the primary washing water to prepare slurry;

the second step is that: filtration

The plate and frame filter is ready, a slurry pump is started, slurry is conveyed to the plate and frame filter for pre-filtration, a filtrate discharge valve is opened at the same time, and the slurry pump is stopped after the pre-filtration is finished; then starting a high-pressure water station, enabling high-pressure water to enter a plate-and-frame filter from a high-pressure water gap to squeeze filter cakes, and stopping the high-pressure water station after the compaction is finished for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter from a blow-drying opening to blow-dry a filter cake; the filtrate generated in the filtering process enters a slurry filtrate tank and is conveyed to a triple-effect evaporation device by using a slurry filtrate pump;

the third step: one-time washing

Starting a primary washing pump to enable secondary washing water in the primary washing tank to enter a filter cake in a cavity of the plate and frame filter to wash the filter cake; simultaneously closing a filtrate discharge valve, opening a primary washing water discharge valve, and enabling generated primary washing water to enter a slurry tank, wherein the using amount of the washing water is the same as the metering value of a primary washing flowmeter in a previous washing period; after the filter cake is washed, stopping the primary washing pump, and then squeezing and drying the filter cake;

the fourth step: second washing

Starting a secondary washing pump to enable condensed water in the secondary washing tank to enter a filter cake in the cavity of the plate and frame filter, and washing the filter cake; closing the first washing water discharge valve, opening the second washing water discharge valve, and allowing the generated second washing water to enter the first washing tank, wherein the usage amount of the washing water is the same as the metering value of the first washing flowmeter in the last washing period; after the filter cake is washed, stopping the secondary washing pump, and squeezing and drying the filter cake;

the fifth step: discharging

And opening the full-automatic plate and frame filter, unloading the filter cake, cleaning the filter cloth, and preparing the plate and frame filter to enter the next working cycle after the filter cloth is cleaned.

The present invention is also characterized in that,

the concrete process of squeezing and drying the filter cake in the third step and the fourth step is as follows: starting a high-pressure water station, enabling high-pressure water to enter a plate-and-frame filter from a high-pressure water port to squeeze filter cakes, and stopping the high-pressure water station after the compaction is finished for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter from a blow-drying opening to blow-dry the filter cake.

The invention has the beneficial effects that:

(1) the system of the invention adopts the full-automatic vertical plate and frame filter to wash the cake, avoids the operation processes of cake discharging and slurry preparation in the middle, simplifies the operation steps and improves the working efficiency.

(2) The system adopts the weighing screw and the flowmeter for metering, ensures that the amount of washing water is 3 times of the mass of the fly ash every time, ensures the washing effect and has the minimum amount of washing water.

(3) The fly ash is desalted by the method of the system, the output product is filter cake shape, the water content is about 15%, the subsequent procedures are dried, added with fluxing agent, granulated, then melted at high temperature, the liquid melting slag is water quenched into glass body, and the flue gas enters into the flue gas processing unit.

(4) The method of the invention respectively adopts the primary washing water, the secondary washing water and the condensed water to wash the fly ash and the filter cake, the salt concentration of the washing water is from high quality to low, thereby not only achieving the purpose of fly ash desalination, but also reducing the consumption of the condensed water to the maximum extent, reducing the discharge of high salt water of the system and lightening the treatment capacity of the follow-up triple-effect evaporation device.

(5) The method can increase or decrease the washing device and times according to the actual washing effect and situation, and can gradually reduce the salt content of the fly ash as long as the salt concentration of each washing water is lower than that used in the previous washing step.

(6) The method solves the problems that when the fly ash is melted at the high temperature of 1400-1500 ℃, chlorine salts such as sodium chloride and potassium chloride volatilize, and the chlorine salts in the flue at the outlet of the melting furnace are cooled, solidified and attached to the flue wall, so that the flue is corroded; and the problem that chlorine salts such as sodium chloride, potassium chloride and the like react with water vapor at the high temperature of 300-900 ℃ to generate hydrogen chloride gas is also solved, the concentration of the hydrogen chloride in the flue gas is reduced, and the corrosion of the hydrogen chloride to flue gas treatment equipment is prevented.

(7) The process for treating the fly ash by melting the plasma is mostly in a pilot-scale research and development stage at home and abroad, and the amount of the fly ash washed by water is mostly about 1 t/d. The process system has the advantages of low one-time investment cost, simple equipment, convenient maintenance and low operation cost, the water content of the filter cake of the plate-and-frame filter press is 15 percent and is greatly reduced compared with the water content of the filter cake of a horizontal screw centrifuge, and the energy consumption of the drying process after desalination is saved.

Drawings

FIG. 1 is a process flow chart of a method for washing and desalting fly ash generated by burning household garbage according to the present invention.

In the figure, 1, a slurry filtrate pump, 2, a slurry filtrate tank, 3, a weighing screw, 4, a slurry stirrer, 5, a slurry tank, 6, a slurry pump, 7, a primary washing tank, 8, a primary washing pump, 9, a primary washing flow meter, 10, a secondary washing pump, 11, a secondary washing flow meter, 12, a secondary washing tank, 13, a plate-and-frame filter, 14, a high-pressure water gap, 15, a filtrate discharge valve, 16, a primary washing water discharge valve, 17, a secondary washing water discharge valve, 18, a blow-dry port, 19, a first valve, 20, a second valve, 21, a third valve, 22, a fourth valve, 23, a fifth valve, 24, a sixth valve, 25, a seventh valve, 26, an eighth valve, 27, a ninth valve, 28, a tenth valve, 29, an eleventh valve, 30, a twelfth valve, 31, a first pipeline, 32, a second pipeline, 33, a third pipeline, 34, a fourth pipeline, 35. a fifth pipeline, 36, a sixth pipeline, 37, a seventh pipeline, 38, an eighth pipeline, 39, a ninth pipeline, 40, a tenth pipeline, 41, an eleventh pipeline, 42, a twelfth pipeline, 43, a thirteenth pipeline, 44, a fourteenth pipeline, 45, a fifteenth pipeline, 46, a sixteenth pipeline, 47, a filtrate outlet, 48, a sewage outlet, 49, a water inlet.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a household garbage incineration fly ash water desalination system, which comprises a fly ash washing system, a filtering system and a cake washing system, as shown in figure 1;

the fly ash washing system comprises a slurry tank 5, a slurry stirrer 4 is arranged at the top of the slurry tank 5, a weighing screw 3 is arranged above the top of the slurry tank 5, and a discharge port of the weighing screw 3 is communicated with the top of the slurry tank 5; a slurry outlet is formed in the side wall of the slurry tank 5, the slurry outlet is connected with a slurry pump 6 through a first pipeline 31, and a discharge port of the slurry pump 6 is connected with a second pipeline 32; the fly ash raw material is conveyed to a slurry tank 5 by a weighing screw 3 according to the mass ratio of 1:3 (the fly ash raw material: the primary washing water), and is fully mixed with the primary washing water to prepare slurry, so that the salt in the fly ash is dissolved in the primary washing water, and the aim of reducing the salt content in the fly ash solid is fulfilled. After the filtration system is ready for feeding, the prepared slurry is transported to the plate and frame filter press 13 by the slurry pump 6.

The filtering system comprises a slurry filtrate pump 1, a discharge hole of the slurry filtrate pump 1 is connected with the triple-effect evaporation device through a seventh pipeline 37, a feed hole of the slurry filtrate pump 1 is connected with a slurry filtrate tank 2 through a sixth pipeline 36, and a feed hole of the slurry filtrate tank 2 at the top filling is connected with a fifth pipeline 35; the device also comprises a plate and frame filter 13, wherein a blow-drying opening 18 of the plate and frame filter 13 is connected with a compressed air storage tank through a ninth pipeline 39, a high-pressure water gap 14 of the plate and frame filter 13 is connected with a high-pressure water station through an eighth pipeline 38, a filtrate outlet 47 of the plate and frame filter 13 is communicated with the top of a slurry tank 5 through a fifteenth pipeline 45, a water inlet 49 of the plate and frame filter 13 is connected with a fourteenth pipeline 44, and a fifth pipeline 35 is communicated with the fifteenth pipeline 45; the second conduit 32 communicates with the fourteenth conduit 44; the plate frame filter 13 is a full-automatic vertical plate frame filter and is used for carrying out solid-liquid separation on slurry. Firstly, under the action of feeding pressure of 0.6MPa, prefiltering slurry, retaining solid materials on filter cloth to form a filter cake, then squeezing the filter cake by using high-pressure water to further remove water in the filter cake, finally blowing the filter cake by using compressed air to blow dry the filter cake, and reducing the moisture content of the filter cake to the minimum, so that salt dissolved in the slurry is separated out after solid-liquid separation operation and enters into filtrate. High-salt water filtrate generated in the filtering process enters a slurry filtrate tank and is conveyed to an external triple-effect evaporation device for treatment through a slurry filtrate pump 1.

The cake washing system comprises a primary washing tank 7, the top of the primary washing tank 7 is communicated with a fifteenth pipeline 45 through a third pipeline 33, the side wall of the primary washing tank 7 is connected with a primary washing pump 8 through a tenth pipeline 40, and the discharge port of the primary washing pump 8 is communicated with a fourteenth pipeline 44 through an eleventh pipeline 41; the device also comprises a secondary washing tank 12, the top of the secondary washing tank 12 is connected with a triple-effect evaporation device through a sixteenth pipeline 46, the side wall of the secondary washing tank 12 is connected with a secondary washing pump 10 through a twelfth pipeline 42, and a discharge hole of the secondary washing pump 10 is communicated with a fourteenth pipeline 44 through a thirteenth pipeline 43. The eleventh pipeline 41 is provided with a primary washing flow meter 9; the thirteenth pipe 43 is provided with a secondary washing flow meter 11. The filter cake is washed by secondary washing water in a primary washing tank 7 under the action of a primary washing pump 8 at the pressure of 0.7MPa, the salt content of the filter cake is reduced, the using amount of the secondary washing water is 3 times (mass ratio) of the fly ash, and a primary washing flowmeter is used for metering 9. After washing, the filter cake is squeezed and dried, and the generated primary washing water enters the slurry tank 5. And similarly, washing the filter cake by using the condensed water in the secondary washing tank 12 under the action of the secondary washing pump 10 and at the pressure of 0.7MPa, further reducing the salt content of the filter cake, wherein the using amount of the condensed water is 3 times (mass ratio) of that of the fly ash, and the condensed water is measured by using a secondary washing flowmeter 11. After washing, squeezing and drying the filter cake, and feeding the generated secondary washing water into a primary washing tank 7, wherein the condensed water comes from a triple-effect evaporation device.

And after the cake washing is finished, opening the plate and frame filter 13, unloading the filter cake, conveying to a drying process, and performing subsequent treatment.

A fifth valve 23 is arranged on the eleventh pipeline 41, and the fifth valve 23 is positioned between the primary washing flow meter 9 and the discharge hole of the primary washing pump 8; a sixth valve 24 is arranged on the thirteenth pipeline 43, and the sixth valve 24 is positioned between the secondary washing flow meter 11 and the discharge hole of the secondary washing pump 10.

The sewage outlet 48 of the plate frame filter 13 is communicated with the top of the slurry tank 5 through a fourth pipeline 34, and the fourth pipeline 34 is provided with a third valve 21.

A twelfth valve 30 is arranged on the ninth pipeline 39; an eleventh valve 29 is arranged on the eighth pipeline 38; the fifteenth pipe 45 is provided with a primary washing water discharge valve 16; a filtrate discharge valve 15 is arranged on the fifth pipeline 35; the third pipe 33 is provided with a secondary washing water discharge valve 17; a ninth valve 27 is arranged on the sixth pipeline 36; the seventh pipe 37 is provided with a tenth valve 28; the first pipeline 31 is provided with a first valve 19; the second pipe 32 is provided with a second valve 20; the sixteenth pipeline 46 is provided with an eighth valve 26; the tenth pipe 40 is provided with a fourth valve 22; the twelfth pipe 42 is provided with a seventh valve 25.

The invention also provides a washing and desalting method for the fly ash generated by burning the household garbage, which adopts the system and is implemented according to the following steps:

the first step is as follows: fly ash washing slurry

Starting a slurry stirrer 4, conveying the fly ash with the mass of 1/3 primary washing water to a slurry tank 5 by using a weighing screw 3 according to the metering value of a primary washing flowmeter 9 in the last washing period, and fully and uniformly mixing the fly ash with the primary washing water to prepare slurry;

the second step is that: filtration

The plate and frame filter 13 is ready, the slurry pump 6 is started, slurry is conveyed to the plate and frame filter 13 for pre-filtration, the filtrate discharge valve 15 is opened at the same time, and the slurry pump 6 is stopped after the pre-filtration is finished; then starting a high-pressure water station, enabling high-pressure water to enter a plate and frame filter 13 from a high-pressure water gap 14 to squeeze filter cakes, and stopping the high-pressure water station after the compaction is finished for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter 13 from a blow-drying opening 18 to blow-dry filter cakes; the filtrate generated in the filtering process enters a slurry filtrate tank 2 and is conveyed to a triple-effect evaporation device by using a slurry filtrate pump 1;

the third step: one-time washing

Starting the primary washing pump 8 to enable secondary washing water in the primary washing tank 7 to enter a filter cake in a cavity of the plate and frame filter 13, and washing the filter cake; simultaneously closing the filtrate discharge valve 15, opening a primary washing water discharge valve 16, and feeding the generated primary washing water into the slurry tank 5, wherein the consumption of the washing water is the same as the metering value of the primary washing flowmeter 9 in the last washing period; after the filter cake is washed, stopping the primary washing pump 8, and then squeezing and drying the filter cake;

the fourth step: second washing

Starting the secondary washing pump 10 to make the condensed water in the secondary washing tank 12 enter the filter cake in the cavity of the plate and frame filter 13 to wash the filter cake; simultaneously closing a primary washing water discharge valve 16, opening a secondary washing water discharge valve 17, and enabling the generated secondary washing water to enter a primary washing tank 7, wherein the using amount of the washing water is the same as the metering value of the primary washing flowmeter 9 in the last washing period; after the filter cake is washed, stopping the secondary washing pump 10, and then squeezing and drying the filter cake;

the fifth step: discharging

And opening the full-automatic plate and frame filter 13, unloading the filter cake, cleaning the filter cloth, and preparing the plate and frame filter (13) to enter the next working cycle, namely filtering, primary washing and secondary washing after the completion. Fly ash wash proportioning can be initiated after filtration is complete.

The concrete process of squeezing and drying the filter cake in the third step and the fourth step is as follows: starting the high-pressure water station, enabling high-pressure water to enter the plate and frame filter 13 from the high-pressure water port 14 to squeeze filter cakes, and stopping the high-pressure water station after the compaction is finished for 10 minutes; finally, compressed air enters the full-automatic plate and frame filter 13 from a blow-drying opening 18 to blow-dry the filter cake.

The method solves the problems of the selection of chlorine salt in the fly ash on the hydrogen chloride removal process of the fly ash flue gas treatment unit by plasma fusion and the influence of the selection of pipeline materials of the fusion furnace and the flue gas treatment unit, overcomes the defects of the traditional desalination technology, adopts the process method of combining the raw material of the washing fly ash and the filter cake of the washing fly ash to dissolve the chlorine salt in the fly ash in the washing water, and then carries out solid-liquid separation to achieve the aim of fly ash desalination. The method is easy to realize automatic operation, practice tests prove that the desalting efficiency is high, the fly ash with the salt content of 30 percent can be washed to the salt content of below 1 percent, the treated fly ash completely meets the requirements of the subsequent melting and flue gas treatment processes, and the material selection requirements of equipment pipelines of fly ash melting and flue gas treatment devices are reduced.