Fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero emission system and method

Abstract

According to the fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero discharge system and method, fly ash is subjected to a multi-stage cross-flow water washing process, soluble chlorine in the fly ash is efficiently removed, the content of the soluble chlorine in washed ash residues is stably lower than 1%, and a foundation is laid for utilization of rear-end building materials; water sources required for dispensing, flushing and the like in the washing process are all taken from water produced in different washing process sections, so that self-circulation treatment and utilization of washing filtrate are realized, the water consumption is greatly reduced, and the operation cost and the environmental protection risk are reduced; the mother liquor generated by the evaporation system flows back to the first-stage washing system, the characteristic of high calcium content in first-stage washing slurry is fully utilized to carry out cooperative treatment with the mother liquor, sulfate radicals in the mother liquor are efficiently removed, enrichment of the sulfate radicals is prevented, the common problem that the mother liquor of the evaporation system is difficult to treat is solved, and meanwhile, the operation cost of the mother liquor is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fly ash water washing, and in particular to a fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero-discharge system and method. Background Art

[0002] Fly ash from the incineration of domestic waste is a hazardous waste. In the current situation of landfill resource shortage, how to effectively detoxify and realize resource treatment is a current problem. Washing fly ash with water is a common method for efficient removal of chloride ions in the current fly ash resource detoxification process. After washing, soluble chloride ions and a small amount of non-stable heavy metals in the fly ash are dissolved. The filtrate after hardness and weight removal is passed through the evaporation system to form industrial salt products. The fly ash after water washing and dechlorination is mechanically dehydrated to form ash products. In the entire washing process, there are pulping water, medicinal water, steam introduction water, evaporation soft water, equipment and ground flushing water, and the generated evaporation mother liquor. From the actual operation point of view, the water taken away by the fly ash after washing can basically maintain a balance with the water generated by the steam introduced into the system. At this time, if the system introduces other water sources, a large amount of high-salt wastewater (or a large amount of external evaporation mother liquor) will be generated to maintain water balance. This method has high treatment costs and great environmental risks. Summary of the invention

[0003] In view of the defects in the prior art, the object of the present invention is to provide a zero-discharge system and method for fly ash cross-flow water washing and dechlorination and comprehensive utilization of filtrate.

[0004] The fly ash cross-flow water washing and dechlorination and filtrate comprehensive utilization zero-discharge system provided by the present invention comprises:

[0005] a slurry tank, which is used to mix fly ash with water to form a slurry;

[0006] A multi-stage cross-current water washing system is connected to the pulping tank, comprising a primary dehydrator, a secondary dehydrator, and a tertiary dehydrator connected in sequence, and a primary filtrate tank, a secondary filtrate tank, and a tertiary filtrate tank for storing filtrate, wherein the multi-stage cross-current water washing system is used to remove soluble chlorine in fly ash step by step;

[0007] The softening and weight removal system is connected to the multi-stage cross-flow water washing system, including a dosing reaction tank, a flocculation tank, and a sedimentation tank, which are used to remove calcium, magnesium hardness and heavy metals in the filtrate;

[0008] A filter connected to the softening and weight removal system to further remove suspended matter from the effluent of the softening and weight removal system;

[0009] A softened water production pool, connected to the filter, for storing water that has passed through the softening and weight removal system and the filter;

[0010] The dosing system is connected with the softening and de-weighting system and the softening water production pool, and is used to prepare the chemicals required for softening and de-weighting;

[0011] A dehydration washing tank, connected to the multi-stage cross-current water washing system and the softening water production tank, is used to store the washing water for the multi-stage cross-current water washing system;

[0012] The evaporation system is connected to the pulping tank and the softening water production pool and is used to evaporate and separate the salt from the softening water production pool;

[0013] A plate heat exchanger connected to the evaporation system is used to cool the produced water of the evaporation system;

[0014] The evaporation water production pool is connected to the pulping tank, the multi-stage cross-flow water washing system and the plate heat exchanger, and is used to store the cooled evaporation water;

[0015] A cooling tower, connected to the plate heat exchanger and the evaporation water production pool, is used to provide cooling water to the plate heat exchanger;

[0016] An ion exchange system, connected to the evaporation water production pool, is used to deeply treat part of the water in the evaporation water production pool;

[0017] The soft water storage tank is connected with the pulping tank, the evaporation system and the ion exchange system, and is used to store the soft water produced by the ion exchange system.

[0018] Preferably, it also includes a water collection well connected to the evaporation water production pool and the pulping tank for collecting ground flushing water.

[0019] Preferably, the pulping tank is connected to the evaporation water production pool through a pulping water replenishment pipe to obtain water replenishment.

[0020] Preferably, the filtrate of the multi-stage cross-flow water washing system is stored in a primary filtrate tank, a secondary filtrate tank, and a tertiary filtrate tank, and is finally removed of impurities through a softening and weight removal system.

[0021] Preferably, the mother liquor produced by the evaporation system is recycled to the primary dehydrator through a mother liquor pipe.

[0022] Preferably, the multi-stage cross-current water washing system produces a washing filtrate after dechlorination, which is stored in the filtrate and sent to the softening and weight removal system through a pump and a stainless steel pipe. The filtrate is subjected to drug addition and flocculation precipitation to achieve the removal of calcium, magnesium hardness and heavy metals in the filtrate. The produced water is connected to the filter through a pump and a stainless steel pipe. The produced water is filtered by the filter and flows into the softening water production pool by gravity. The softened produced water is a clear liquid, which is recycled to the dosing system and the dehydration flushing tank through a pump and a stainless steel pipe. The dosing system is connected to the softening and weight removal system through a dosing pump and a plastic dosing pipe. The dehydration flushing tank is connected to each flushing point in the multi-stage water washing system through a pressure pump and a stainless steel dehydrator flushing pipe.

[0023] Preferably, the effluent from the softened water production pool enters the evaporation system through a pressure pump and a stainless steel pipe. After the softened water is evaporated, the output is industrial salt. The evaporation system is connected to the plate heat exchanger through a stainless steel evaporation water production pipe. The produced water enters the evaporation water production pool after being cooled by the plate heat exchanger; the cold medium inlet and outlet ends of the plate heat exchanger are respectively connected to the cooling tower through the cooling tower outlet pipe and the cooling tower return pipe; the mother liquor generated by the evaporation system is recycled to the primary water washing through the mother liquor pipe.

[0024] Preferably, it also includes a first washing tank and a second washing tank;

[0025] The slurry tank is connected to the primary dewatering machine through a slurry pump and a stainless steel pipe. The fly ash slurry is dehydrated by the primary dewatering machine to achieve the first-stage mud-water separation.

[0026] The filtrate produced by the primary dehydrator flows into the first wash filtrate tank through a stainless steel pipeline, and the slag phase enters the first wash tank through a screw conveyor. The first wash tank is equipped with a stirrer. The slag phase is fully stirred and mixed with the third wash filtrate from the third wash filtrate tank in the first wash tank to form a slurry, which is then pumped to the second wash dehydrator through a slag slurry pump and a stainless steel pipeline. The fly ash slurry is separated from the second wash dehydrator to achieve the second-level mud and water separation;

[0027] The filtrate produced by the secondary dehydrator flows into the secondary washing filtrate tank through a stainless steel pipe, and the slag phase enters the secondary washing tank through a screw conveyor. The secondary washing tank is equipped with a stirrer. The slag phase is fully stirred and mixed with the evaporation water from the evaporation water production pool in the secondary washing tank to form a slurry, which is then sent to the tertiary washing dehydrator through a slag slurry pump and a stainless steel pipe. The fly ash slurry is separated into the third level of mud and water by the tertiary dehydrator;

[0028] The filtrate produced by the three-stage dehydrator flows by gravity into the three-wash filtrate tank for storage through a stainless steel pipe, and is recycled to the first wash tank through a pump and a stainless steel pipe.

[0029] Preferably, the effluent from the evaporation water production pool is used for cooling tower water replenishment, evaporation system flushing, pulping tank water replenishment, soft water production, secondary washing tank water replenishment and ground flushing.

[0030] Preferably, the softened water is used for replenishing the compressor of the evaporation system and flushing the mechanical seals in the cross-flow water washing system.

[0031] The zero-discharge method for fly ash cross-flow water washing and chlorine removal and filtrate comprehensive utilization provided by the present invention comprises the following steps:

[0032] Step 1: Fly ash enters the pulping tank, and the pulping tank is replenished with water through the pulping water replenishment pipe;

[0033] Step 2: The pulping tank is connected to the primary dewatering machine through a slurry pump and a stainless steel pipe. The fly ash slurry is dehydrated by the primary dewatering machine to achieve the first-stage mud-water separation; the filtrate produced by the primary dewatering machine flows into the first-stage filtrate tank by gravity through a stainless steel pipe, and the slag phase enters the first-stage washing tank through a screw conveyor. The first-stage washing tank is equipped with a stirrer. The slag phase is fully stirred and mixed with the third-stage washing filtrate from the third-stage washing filtrate tank in the first-stage washing tank to form a slurry, and is pumped to the second-stage washing dewatering machine through a slurry pump and a stainless steel pipe. The fly ash slurry is dehydrated by the second-stage washing dewatering machine to achieve the second-stage mud-water separation. Separation; the filtrate produced by the secondary dehydrator flows into the secondary washing filtrate tank through a stainless steel pipeline, and the slag phase enters the secondary washing tank through a screw conveyor. The secondary washing tank is equipped with a stirrer. The slag phase is fully mixed with the evaporation water from the evaporation water production pool in the secondary washing tank to form a slurry, which is then sent to the tertiary washing dehydrator through a slag slurry pump and a stainless steel pipeline. The fly ash slurry is separated from the third-level mud and water by the tertiary dehydrator; the filtrate produced by the tertiary dehydrator flows into the tertiary washing filtrate tank for storage through a stainless steel pipeline, and is recycled to the first washing tank through a pump and a stainless steel pipeline;

[0034] Step 3: After dechlorination, the multi-stage cross-flow water washing system produces a washing filtrate which is stored in the filtrate and sent to the softening and weight removal system through a pump and a stainless steel pipe. The filtrate is subjected to dosing and flocculation precipitation, thereby achieving the removal of calcium, magnesium hardness and heavy metals in the filtrate. The produced water is connected to the filter through a pump and a stainless steel pipe. The produced water is filtered by the filter and flows into the softening water production pool by gravity. The softened produced water is a clear liquid, which is recycled to the dosing system and the dehydration flushing tank through a pump and a stainless steel pipe; the dosing system is connected to the softening and weight removal system through a dosing pump and a plastic dosing pipe, and the dehydration flushing tank is connected to each flushing point in the multi-stage water washing system through a pressure pump and a stainless steel dehydrator flushing pipe;

[0035] Step 4: The softened water output from the water production pool enters the evaporation system through a pressure pump and a stainless steel pipe. After the softened water is evaporated, the output is industrial salt. The evaporation system is connected to the plate heat exchanger through a stainless steel evaporation water production pipe. The output water enters the evaporation water production pool after being cooled by the plate heat exchanger. The cold medium inlet and outlet ends of the plate heat exchanger are connected to the cooling tower through the cooling tower outlet pipe and the cooling tower return pipe respectively. The mother liquor generated by the evaporation system is reused to the primary water washing through the mother liquor pipe;

[0036] Step 5: The effluent from the evaporation water production pool has a common destination;

[0037] Destination 1: Cooling tower water replenishment. The evaporation water production pool is connected to the cooling tower through a pump and a cooling tower water replenishment pipe, and is used to replenish the cooling tower evaporation and sewage loss;

[0038] Destination 2: Evaporation system flushing water. The evaporation water production pool is connected to the evaporation system through a pump and an evaporation flushing pipe, and is used for clearing blockages and cleaning water in the evaporation system.

[0039] Destination three: water replenishment for pulping tank. The evaporation water production pool is connected to the pulping tank through a pump and pulping water replenishment pipe, which is used to replenish water for fly ash pulping;

[0040] Destination 4: Soft water production. Soft water is used for water replenishment of the compressor in the evaporation system and for flushing the seal of the slurry pump in the cross-flow water washing system. The evaporation water production pool is connected to the ion exchange system through a pump and an ion exchange water inlet pipe. The ion exchange water flows into the soft water storage tank by gravity. The soft water storage tank is connected to the evaporation system through a pump and an evaporation soft water replenishment pipe to realize water replenishment and temperature adjustment of the compressor in the evaporation system. The soft water storage tank is connected to the cross-flow water washing system through a pump and a seal flushing pipe to realize the seal flushing of various transfer pumps in the cross-flow water washing system.

[0041] Direction 5: Water replenishment for the secondary washing tank. The evaporation water production pool is connected to the secondary washing tank through a pump and a tertiary pulping water replenishment pipe;

[0042] Destination six: Ground flushing. The evaporation water pool is used for floor flushing in the production workshop through a pump and a ground flushing pipe. The ion exchange concentrate flows into the collection well through the concentrate pipe and is collected together with the wastewater after flushing and reused in the pulping tank through a pump and a pipe.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) Through the method of the present invention, fly ash is subjected to a multi-stage cross-flow water washing process to achieve efficient removal of soluble chlorine in the fly ash, so that the soluble chlorine content in the washed ash is stably less than 1%, laying a foundation for the back-end building material utilization;

[0045] (2) In the present invention, the water source required for the preparation and flushing of the water washing process is taken from the water produced in different process stages of the water washing process, thus realizing the self-circulation treatment and utilization of the water washing filtrate, greatly reducing the water consumption, and reducing the operating cost and environmental risks;

[0046] (3) In the present invention, the mother liquor generated by the evaporation system is refluxed to the primary water washing system, and the high calcium content in the primary water washing slurry is fully utilized to carry out synergistic treatment with the mother liquor, thereby achieving efficient removal of sulfate ions in the mother liquor and preventing the enrichment of sulfate ions, thereby solving the common problem of difficult disposal of the mother liquor in the evaporation system and reducing the operating cost of the mother liquor. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0048] Figure 1 This is a schematic diagram of the fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero-discharge system structure;

[0049] In the figure: pulping tank 1; multi-stage cross-flow washing system 2, primary dehydrator 2-1, secondary dehydrator 2-2, tertiary dehydrator 2-3, primary washing tank 2-4, primary filtrate tank 2-8, secondary filtrate tank 2-5, secondary washing tank 2-6, tertiary filtrate tank 2-7; softening and weight removal system 3; filter 4; softening water production tank 5; dosing system 6; dehydration and flushing tank 7; evaporation system 8; plate heat exchanger 9; evaporation water production tank 10; cooling tower 11; ion exchange system 12; soft water storage Tank 13; water collection well 14; dosing pipe 6-1; dehydrator flushing pipe 7-1; mother liquor pipe 8-1, evaporation water production pipe 8-2; cooling water supply pipe 10-1, evaporation flushing pipe 10-2, pulping water supply pipe 10-3, ion exchange water inlet pipe 10-4, tertiary pulping water supply pipe 10-5, ground flushing pipe 10-6; cooling tower outlet pipe 11-1, cooling tower return pipe 11-2; concentrate pipe 12-1; evaporation soft water supply pipe 13-1; machine seal flushing pipe 13-2. DETAILED DESCRIPTION

[0050] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0051] Example

[0052] like Figure 1 As shown, the present invention provides a fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero-discharge system, comprising:

[0053] Slurry tank 1: It is composed of a steel tank body and a stirrer. The fly ash is formed into a slurry through water replenishment and the stirrer in the tank.

[0054] Multi-stage cross-flow water washing system 2: comprising a primary dehydrator 2-1, a secondary washing dehydrator 2-2, a tertiary washing dehydrator 2-3, a primary washing tank 2-4, a primary washing filtrate tank 2-8, a secondary washing filtrate tank 2-5, a secondary washing tank 2-6, and a tertiary washing filtrate tank 2-7; fly ash is washed by multi-stage cross-flow water washing to achieve efficient removal of soluble chlorine.

[0055] Softening and weight removal system 3: It includes a dosing reaction tank, a flocculation tank, and a sedimentation tank. The calcium and magnesium hardness and heavy metals in the filtrate after fly ash washing are removed through dosing reaction, flocculation and sedimentation.

[0056] Filter 4: removes suspended matter from the effluent of softening system 3.

[0057] Softening water production pool 5: stores the water produced by the washing filtrate after pre-treatment of removing hardness and heaviness.

[0058] Dosing system 6: Preparation of the reagents required for removing hardness and weight in the softening and weight removal system 3.

[0059] Dehydration and flushing tank 7: used to store flushing water for flushing equipment in the multi-stage cross-flow water washing system, and the water source comes from the softening water production tank 5.

[0060] Evaporation system 8: evaporates and separates the high-salt water in the softening water production pool 5 to obtain industrial salt products.

[0061] Plate heat exchanger 9: cools the water produced by the evaporation system 8.

[0062] Evaporation water pool 10: stores the water produced by the evaporation system 8 after cooling.

[0063] Cooling tower 11: provides cooling water for the plate heat exchanger.

[0064] Ion exchange system 12: deeply treats part of the water in the evaporation water production pool 10 to produce soft water for flushing pump seals in the evaporation system 8 and the water washing system 2.

[0065] Soft water storage tank 13: stores the soft water produced by the ion exchange system 12.

[0066] Collection well 14: collects and stores ground flushing water.

[0067] Dosing pipe 6-1; dehydrator flushing pipe 7-1; mother liquor pipe 8-1; evaporation water production pipe 8-2; cooling water supply pipe 10-1; evaporation flushing pipe 10-2; pulping water supply pipe 10-3; ion exchange water inlet pipe 10-4; tertiary pulping water supply pipe 10-5; ground flushing pipe 10-6; cooling tower outlet pipe 11-1; cooling tower return pipe 11-2; concentrate pipe 12-1; evaporation soft water supply pipe 13-1; machine seal flushing pipe 13-2.

[0068] The implementation process includes the following steps:

[0069] Step 1: Fly ash from the municipal solid waste incineration plant enters the pulping tank 1, and the pulping tank 1 is replenished with water through the pulping water replenishing pipe 10-3.

[0070] Step 2: The pulping tank 1 is connected to the primary dewatering machine 2-1 through a slurry pump and a stainless steel pipeline. The fly ash slurry is dehydrated by the primary dewatering machine 2-1 to achieve the first-stage mud-water separation; the filtrate produced by the primary dewatering machine 2-1 flows into the first washing filtrate tank 2-8 by gravity through a stainless steel pipeline, and the slag phase (water content 30%-40%) enters the first washing tank 2-4 through a screw conveyor. The first washing tank 2-4 is provided with a stirrer. The slag phase is fully stirred and mixed with the third washing filtrate from the third washing filtrate tank 2-7 in the first washing tank 2-4 to form a slurry, and is pumped to the second washing dewatering machine 2-2 through a slurry pump and a stainless steel pipeline. The fly ash slurry is separated from the second washing dewatering machine 2-2 by the second washing dewatering machine 2-2; the secondary dewatering machine 2-2 produces The filtrate flows into the secondary washing filtrate tank 2-5 by gravity through a stainless steel pipe, and the slag phase (water content 30%-40%) enters the secondary washing tank 2-6 through a screw conveyor. A stirrer is provided in the secondary washing tank 2-6. The slag phase is fully stirred and mixed with the evaporation water from the evaporation water production pool 10 in the secondary washing tank 2-6 to form a slurry, which is then sent to the tertiary washing dehydrator 2-3 through a slag slurry pump and a stainless steel pipe. The fly ash slurry is separated from the fly ash by the tertiary dehydrator 2-3; the filtrate generated by the tertiary dehydrator 2-3 flows into the tertiary washing filtrate tank 2-7 for storage by gravity through a stainless steel pipe, and is reused to the primary washing tank 2-4 through a pump and a stainless steel pipe. The generated slag phase (water content 20%-30%) is transported out for use in building materials.

[0071] Step 3: The multi-stage cross-current water washing system 2 produces a water washing filtrate (a wash filtrate) after dechlorination, which is stored in 2-8 and sent to the softening and weight removal system 3 through a pump and a stainless steel pipe. The filtrate is treated with dosing and flocculation precipitation to achieve the removal of calcium and magnesium hardness and heavy metals in the filtrate. The produced water is connected to the filter 4 through a pump and a stainless steel pipe. The produced water is filtered by the filter 4 and flows into the softening water production pool 5 by gravity. The softened produced water is a clear liquid, which is recycled to the dosing system 6 and the dehydration flushing tank 7 through a pump and a stainless steel pipe. The dosing system 6 is connected to the softening and weight removal system 3 through a dosing pump and a plastic dosing pipe 6-1, and the dehydration flushing tank 7 is connected to each flushing point in the multi-stage water washing system 2 through a pressure pump and a stainless steel dehydrator flushing pipe 7-1.

[0072] Step 4: The water from the softened water production pool 5 enters the evaporation system 8 through a pressure pump and a stainless steel pipe. After the softened water is evaporated, the output is industrial salt. The evaporation system 8 is connected to the plate heat exchanger 9 through the stainless steel evaporation water production pipe 8-2. The water is cooled by the plate heat exchanger 9 and then enters the evaporation water production pool 10. The cold medium inlet and outlet ends of the plate heat exchanger 9 are respectively connected to the cooling tower 11 through the cooling tower outlet pipe 11-1 and the cooling tower return pipe 11-2. The mother liquor generated by the evaporation system 8 is recycled to the primary water washing 2-1 through the mother liquor pipe 8-1.

[0073] Step 5: The effluent from the evaporation water production pool 10 has 6 destinations.

[0074] Destination 1: Cooling tower 11 replenishes water. The evaporation water production pool 10 is connected to the cooling tower 11 through a pump and a cooling tower replenishment pipe 10-1, which is used to replenish water for cooling tower evaporation and sewage loss.

[0075] Destination two: flushing water of the evaporation system 8. The evaporation water production pool 10 is connected to the evaporation system 8 through a pump and an evaporation flushing pipe 10-2, and is used for clearing blockages and cleaning water of the evaporation system.

[0076] Destination three: water replenishment for the pulping tank. The evaporation water production pool 10 is connected to the pulping tank 1 through a pump and a pulping water replenishment pipe 10-3, and is used to replenish water for fly ash pulping.

[0077] Destination 4: Soft water is produced. Soft water is used for water replenishment of the compressor of the evaporation system and for flushing the seal of the slurry pump of the cross-flow water washing system. The evaporation water production pool 10 is connected to the ion exchange system 12 through a pump and an ion exchange water inlet pipe 10-4. The ion exchange water flows into the soft water storage tank 13 by gravity. The soft water storage tank 13 is connected to the evaporation system 8 through a pump and an evaporation soft water replenishment pipe 13-1 to realize water replenishment and temperature adjustment of the compressor in the evaporation system 8. The soft water storage tank 13 is connected to the cross-flow water washing system 2 through a pump and a seal flushing pipe 13-2 to realize the seal flushing of various transfer pumps in the cross-flow water washing system 2.

[0078] Direction 5: Water replenishment of the secondary washing tank 2-6. The evaporation water production pool 10 is connected to the secondary washing tank 2-6 through a pump and a tertiary pulping water replenishment pipe 10-5.

[0079] Destination 6: Ground flushing, the evaporation water pool 10 is used for ground flushing in the production workshop through the pump and ground flushing pipe 10-6. The ion exchange concentrate flows into the water collection well 14 through the concentrate pipe 12-1, and is collected together with the flushing sewage through the pump and pipeline for reuse in the pulping tank 1.

[0080] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0081] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0082] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A fly ash cross-flow water washing dechlorination and filtrate comprehensive utilization zero-discharge system, characterized in that: include: A slurry tank (1) for mixing fly ash with water to form a slurry; A multi-stage cross-current water washing system (2) is connected to the pulping tank (1), comprising a primary dehydrator (2-1), a secondary dehydrator (2-2), a tertiary dehydrator (2-3) connected in sequence, and a primary filtrate tank (2-8), a secondary filtrate tank (2-5), and a tertiary filtrate tank (2-7) for storing filtrate, wherein the multi-stage cross-current water washing system (2) is used to remove soluble chlorine in fly ash step by step; The softening and weight removal system (3) is connected to the multi-stage cross-flow water washing system (2), and includes a dosing reaction tank, a flocculation tank, and a sedimentation tank, and is used to remove calcium, magnesium hardness and heavy metals in the filtrate; A filter (4) connected to the softening and weight removal system (3) for further removing suspended matter from the effluent of the softening and weight removal system (3); A softened water production pool (5), connected to the filter (4), for storing water that has passed through the softening and weight removal system (3) and the filter (4); A dosing system (6) is connected to the softening and weight removal system (3) and the softening water production pool (5) and is used to prepare the reagents required for softening and weight removal; A dehydration and washing tank (7), connected to the multi-stage cross-current water washing system (2) and the softening water production tank (5), and used for storing washing water for the multi-stage cross-current water washing system (2); An evaporation system (8) is connected to the pulping tank (1) and the softening water production pool (5) and is used to evaporate and desalinate the water in the softening water production pool (5); A plate heat exchanger (9) connected to the evaporation system (8) and used to cool the produced water of the evaporation system (8); The evaporation water production pool (10) is connected to the pulping tank (1), the multi-stage cross-flow water washing system (2) and the plate heat exchanger (9) and is used to store the evaporated water after cooling; A cooling tower (11) connected to the plate heat exchanger (9) and the evaporation water production pool (10) for providing cooling water to the plate heat exchanger (9); An ion exchange system (12) is connected to the evaporation water production pool (10) and is used to perform deep treatment on part of the water in the evaporation water production pool (10); The soft water storage tank (13) is connected to the pulping tank (1), the evaporation system (8) and the ion exchange system (12), and is used to store the soft water produced by the ion exchange system (12).

2. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 1 is characterized in that: It also includes a water collection well (14) connected to the evaporation water production pool (10) and the pulping tank (1) for collecting ground flushing water.

3. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 1 is characterized in that: The pulping tank (1) is connected to the evaporation water production pool (10) through a pulping water replenishment pipe (10-3) to obtain water replenishment; The mother liquor generated by the evaporation system (8) is recycled to the primary dehydrator (2-1) through the mother liquor pipe (8-1).

4. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 1 is characterized in that: The filtrate of the multi-stage cross-current water washing system (2) is stored in a primary washing filtrate tank (2-8), a secondary washing filtrate tank (2-5), and a tertiary washing filtrate tank (2-7), and is finally removed of impurities by a softening and deweighting system (3).

5. The fly ash cross-flow water elution dechlorination and filtrate comprehensive utilization zero-discharge system according to claim 1, characterized in that: The multi-stage cross-current washing system (2) produces a washing filtrate after dechlorination and stores it in (2-8), and sends it to the softening and deweighting system (3) through a pump and a stainless steel pipe. The filtrate is subjected to dosing and flocculation precipitation, thereby achieving the removal of calcium, magnesium hardness and heavy metals in the filtrate. The produced water is connected to the filter (4) through a pump and a stainless steel pipe. The produced water is filtered by the filter (4) and flows into the softening water production pool (5) by gravity. The softened produced water is a clear liquid and is recycled to the dosing system (6) and the dehydration flushing tank (7) through a pump and a stainless steel pipe. The dosing system (6) is connected to the softening and deweighting system (3) through a dosing pump and a plastic dosing pipe (6-1), and the dehydration flushing tank (7) is connected to each flushing point in the multi-stage washing system (2) through a pressure pump and a stainless steel dehydrator flushing pipe (7-1).

6. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 1, characterized in that: The water from the softened water production pool (5) enters the evaporation system (8) through a pressure pump and a stainless steel pipe. After the softened water is evaporated, the output is industrial salt. The evaporation system (8) is connected to the plate heat exchanger (9) through a stainless steel evaporation water production pipe (8-2). The water is cooled by the plate heat exchanger (9) and then enters the evaporation water production pool (10); the cold medium inlet and outlet ends of the plate heat exchanger (9) are respectively connected to the cooling tower (11) through a cooling tower outlet pipe (11-1) and a cooling tower return pipe (11-2); the mother liquor generated by the evaporation system (8) is recycled to the primary water washing (2-1) through the mother liquor pipe (8-1).

7. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 1 is characterized in that: It also includes a first washing tank (2-4) and a second washing tank (2-6); The slurry making tank (1) is connected to the primary dewatering machine (2-1) via a slurry pump and a stainless steel pipe, and the fly ash slurry is dehydrated by the primary dewatering machine (2-1) to achieve the first-stage mud-water separation; The filtrate generated by the primary dehydrator (2-1) flows by gravity into a first wash filtrate tank (2-8) through a stainless steel pipeline, and the slag phase enters a first wash tank (2-4) through a screw conveyor. A stirrer is provided in the first wash tank (2-4). The slag phase is fully stirred and mixed with the third wash filtrate from the third wash filtrate tank (2-7) in the first wash tank (2-4) to form a slurry, and is pumped to the second wash dehydrator (2-2) through a slag slurry pump and a stainless steel pipeline. The fly ash slurry is separated from the fly ash by the second wash dehydrator (2-2) to achieve a second-stage mud-water separation. The filtrate produced by the secondary dehydrator (2-2) flows by gravity into the secondary washing filtrate tank (2-5) through a stainless steel pipe, and the slag phase enters the secondary washing tank (2-6) through a screw conveyor. The secondary washing tank (2-6) is provided with a stirrer. The slag phase is fully stirred and mixed with the evaporation water from the evaporation water production pool (10) in the secondary washing tank (2-6) to form a slurry, which is then sent to the tertiary washing dehydrator (2-3) through a slag slurry pump and a stainless steel pipe. The fly ash slurry is separated into the third level of mud and water by the tertiary dehydrator (2-3); The filtrate produced by the three-stage dehydrator (2-3) flows by gravity into the three-wash filtrate tank (2-7) for storage through a stainless steel pipeline, and is recycled to the first wash tank (2-4) through a pump and a stainless steel pipeline.

8. The fly ash cross-flow water elution and chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 7, characterized in that: The water output from the evaporation water production pool (10) is used for water replenishment of the cooling tower (11), flushing of the evaporation system (8), water replenishment of the pulping tank (1), making soft water, water replenishment of the secondary washing tank (2-6) and ground flushing.

9. The fly ash cross-flow water elution chlorine removal and filtrate comprehensive utilization zero-discharge system according to claim 8, characterized in that: The softened water is used for water replenishment of the compressor of the evaporation system (8) and for flushing the mechanical seals in the cross-flow water washing system (2).

10. A zero-discharge method for fly ash cross-flow water washing and dechlorination and filtrate comprehensive utilization, characterized in that: The fly ash cross-flow water washing and dechlorination and filtrate comprehensive utilization zero-discharge system according to any one of claims 1 to 9 comprises the following steps: Step 1: Fly ash enters the pulping tank, and the pulping tank is replenished with water through the pulping water replenishment pipe; Step 2: The pulping tank is connected to the primary dewatering machine through a slurry pump and a stainless steel pipe. The fly ash slurry is dehydrated by the primary dewatering machine to achieve the first-stage mud-water separation; the filtrate produced by the primary dewatering machine flows into the first-stage filtrate tank by gravity through a stainless steel pipe, and the slag phase enters the first-stage washing tank through a screw conveyor. The first-stage washing tank is equipped with a stirrer. The slag phase is fully stirred and mixed with the third-stage washing filtrate from the third-stage washing filtrate tank in the first-stage washing tank to form a slurry, and is pumped to the second-stage washing dewatering machine through a slurry pump and a stainless steel pipe. The fly ash slurry is dehydrated by the second-stage washing dewatering machine to achieve the second-stage mud-water separation. Separation; the filtrate produced by the secondary dehydrator flows into the secondary washing filtrate tank through a stainless steel pipeline, and the slag phase enters the secondary washing tank through a screw conveyor. The secondary washing tank is equipped with a stirrer. The slag phase is fully mixed with the evaporation water from the evaporation water production pool in the secondary washing tank to form a slurry, which is then sent to the tertiary washing dehydrator through a slag slurry pump and a stainless steel pipeline. The fly ash slurry is separated from the third-level mud and water by the tertiary dehydrator; the filtrate produced by the tertiary dehydrator flows into the tertiary washing filtrate tank for storage through a stainless steel pipeline, and is recycled to the first washing tank through a pump and a stainless steel pipeline; Step 3: After dechlorination, the multi-stage cross-flow water washing system produces a washing filtrate which is stored in the filtrate and sent to the softening and weight removal system through a pump and a stainless steel pipe. The filtrate is subjected to dosing and flocculation precipitation, thereby achieving the removal of calcium, magnesium hardness and heavy metals in the filtrate. The produced water is connected to the filter through a pump and a stainless steel pipe. The produced water is filtered by the filter and flows into the softening water production pool by gravity. The softened produced water is a clear liquid, which is recycled to the dosing system and the dehydration flushing tank through a pump and a stainless steel pipe; the dosing system is connected to the softening and weight removal system through a dosing pump and a plastic dosing pipe, and the dehydration flushing tank is connected to each flushing point in the multi-stage water washing system through a pressure pump and a stainless steel dehydrator flushing pipe; Step 4: The softened water output from the water production pool enters the evaporation system through a pressure pump and a stainless steel pipe. After the softened water is evaporated, the output is industrial salt. The evaporation system is connected to the plate heat exchanger through a stainless steel evaporation water production pipe. The output water enters the evaporation water production pool after being cooled by the plate heat exchanger. The cold medium inlet and outlet ends of the plate heat exchanger are connected to the cooling tower through the cooling tower outlet pipe and the cooling tower return pipe respectively. The mother liquor generated by the evaporation system is reused to the primary water washing through the mother liquor pipe; Step 5: The effluent from the evaporation water production pool has a common destination; Destination 1: Cooling tower water replenishment. The evaporation water production pool is connected to the cooling tower through a pump and a cooling tower water replenishment pipe, and is used to replenish the cooling tower evaporation and sewage loss; Destination 2: Evaporation system flushing water. The evaporation water production pool is connected to the evaporation system through a pump and an evaporation flushing pipe, and is used for clearing blockages and cleaning water in the evaporation system. Destination three: water replenishment for pulping tank. The evaporation water production pool is connected to the pulping tank through a pump and pulping water replenishment pipe, which is used to replenish water for fly ash pulping; Destination 4: Soft water production. Soft water is used for water replenishment of the compressor in the evaporation system and for flushing the seal of the slurry pump in the cross-flow water washing system. The evaporation water production pool is connected to the ion exchange system through a pump and an ion exchange water inlet pipe. The ion exchange water flows into the soft water storage tank by gravity. The soft water storage tank is connected to the evaporation system through a pump and an evaporation soft water replenishment pipe to realize water replenishment and temperature adjustment of the compressor in the evaporation system. The soft water storage tank is connected to the cross-flow water washing system through a pump and a seal flushing pipe to realize the seal flushing of various transfer pumps in the cross-flow water washing system. Direction 5: Water replenishment for the secondary washing tank. The evaporation water production pool is connected to the secondary washing tank through a pump and a tertiary pulping water replenishment pipe; Destination six: Ground flushing. The evaporation water pool is used for floor flushing in the production workshop through a pump and a ground flushing pipe. The ion exchange concentrate flows into the collection well through the concentrate pipe and is collected together with the wastewater after flushing and reused in the pulping tank through a pump and a pipe.

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