Landfill leachate crystallization treatment method and equipment
By using a design that fits the gap between the rotating cleaning rod and the cleaning scraper, the problem of scaling on the heat exchange tubes is solved, heat transfer efficiency is improved, energy consumption and maintenance costs are reduced, and the stable operation of the MVR system is ensured.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG HUANYUBOXIN CHEM ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2026-03-16
- Publication Date
- 2026-05-01
AI Technical Summary
When MVR evaporation crystallization is used to treat landfill leachate, scaling of heat exchange tubes leads to reduced heat transfer efficiency, increased energy consumption, reduced flow cross-section, and equipment corrosion risk. Existing technologies cannot achieve real-time and efficient anti-scaling and cannot meet the requirements for long-term stable operation.
The design employs a gap fit between the rotating cleaning rod and the cleaning scraper. By monitoring the scaling condition on the inner wall of the heat exchange tube online, the scraper removes the scaling layer in real time. Combined with the turbulence effect, it reduces ion adhesion, avoids hard contact wear, achieves scale prevention and extends component life, and reduces operation and maintenance costs.
It improves heat exchange efficiency, reduces energy consumption, extends equipment lifespan, reduces maintenance frequency and costs, and ensures the stable operation of the MVR system.
Smart Images
Figure CN121948772A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of landfill leachate crystallization treatment equipment, specifically to a landfill leachate crystallization treatment method and equipment. Background Technology
[0002] Landfill leachate is a high-concentration organic wastewater generated during landfill and incineration. Its composition is complex and contains a large amount of recalcitrant organic matter, heavy metal ions, and high-salt components, making it extremely difficult to treat. MVR evaporation crystallization technology has become one of the core processes for the deep treatment of landfill leachate due to its advantages such as low energy consumption, high volume reduction rate, and salt recovery. It uses a compressor to compress and heat the secondary steam generated by evaporation, and uses the heated steam as a heat source for recycling, thereby achieving efficient evaporation concentration and crystallization separation of leachate.
[0003] However, in MVR evaporation and crystallization treatment of landfill leachate, scaling on heat exchange tubes is a key bottleneck restricting the stable operation of the equipment. Landfill leachate is rich in hardness ions such as calcium, magnesium, and silicon. During the evaporation and concentration process, the continuous evaporation of water causes the concentration of sparingly soluble salts to exceed the solubility product, which easily forms dense deposits such as calcium carbonate, calcium sulfate, and silica scale on the inner wall of the heat exchange tubes. Scaling not only significantly reduces the heat transfer efficiency of the heat exchange tubes, leading to a sharp increase in system energy consumption, but also reduces the flow cross-section of the heat exchange tubes and increases fluid resistance, which can cause pipe blockage in severe cases. At the same time, concentration cells are easily formed under the scale layer, causing local corrosion and perforation of the heat exchange tubes. Uneven scaling can also lead to uneven heating of the heat exchange tubes, increasing the risk of equipment burnout. Given the high scaling tendency of landfill leachate, existing technologies cannot achieve real-time and efficient anti-scaling of heat exchange tubes, and cannot meet the requirements for long-term stable operation of MVR evaporators. Summary of the Invention
[0004] The purpose of this invention is to provide a method and equipment for treating landfill leachate crystallization, so as to solve the problems mentioned in the background art.
[0005] To solve the above-mentioned technical problems, the present invention provides a method for treating landfill leachate by crystallization, comprising the following steps: Step a: Pretreatment, the landfill leachate is pretreated to remove suspended solids, grease and some organic matter; Step b: MVR evaporation and concentration. Start the compression device and circulation device. The pretreated leachate enters the heat exchange tube. The compression device compresses and heats the secondary steam and uses it as a heat source to heat the leachate. Step c: Crystallization and separation. The concentrated water is fed into the crystallization equipment for evaporation and crystallization. The crystallization product is separated and recovered. The secondary steam is recycled. The condensate is collected and further treated for reuse. Step d: Heat exchange tube cleaning preparation. Based on the scale buildup on the inner wall of the heat exchange tube, activate the drive mechanism to drive the cleaning mechanism to clean the inner wall of the heat exchange tube.
[0006] In a further embodiment, in step b, the flow rate of the percolate in the heat exchange tube is 1.0-1.5 m / s, and the evaporation temperature is controlled at 80-90°C.
[0007] In a further embodiment, in step c, the evaporation temperature of the crystallizer is controlled at 70-80°C.
[0008] The present invention also provides a landfill leachate crystallization treatment device, including an evaporator body, a compressor, a crystallizer and a supporting piping system. The evaporator body is provided with a heat exchange tube assembly inside. Each heat exchange tube in the heat exchange tube assembly is coaxially provided with a rotating cleaning rod. A cleaning scraper is embedded in the rotating cleaning rod on the surface close to the inner wall of the heat exchange tube. The outer edge of the cleaning scraper is clearance-fitted with the inner wall of the heat exchange tube. A first shaft and a second shaft are respectively fixed to both ends of the rotating cleaning rod. A transmission gear is fixed to the top of the first shaft. A drive motor is fixed to the top of the outer shell of the evaporator body. A connecting plate is fixed to the output end of the drive motor. A gear ring that meshes with the transmission gear is fixed to the bottom of the connecting plate.
[0009] In a further embodiment, an annular guide seat is fixedly connected inside the evaporator body and is rotatably connected to the drive motor shaft, and an annular guide block is fixedly connected to the top of the connecting plate and is slidably engaged with the annular guide seat.
[0010] In a further embodiment, a partition is fixedly connected inside the evaporator body, the first shaft is rotatably connected to the partition, and a bracket is fixedly connected inside the evaporator body, the second shaft is rotatably connected to the bracket.
[0011] In a further embodiment, a circulating pump and a gas-liquid separator are also included. The input end of the circulating pump is connected to the bottom of the evaporator body through a pipe, and the input end of the circulating pump is connected to the crystallizer mother liquor outlet through a pipe.
[0012] In a further embodiment, the exhaust port of the crystallizer and the gas-liquid separator are connected by a pipeline, and the exhaust port of the gas-liquid separator is connected to the input end of the compressor.
[0013] In a further embodiment, a waste discharge pipe is connected to the bottom of the evaporator body, and a raw liquid pipe is connected to the connecting pipe between the circulation pump and the evaporator.
[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a gap fit between the cleaning scraper and the inner wall of the heat exchange tube. This allows for real-time removal of the initial scale layer on the tube wall through the rotation of the cleaning scraper, preventing the formation of hard scale. It also avoids the wear or jamming of the cleaning scraper caused by gapless contact, balancing scale prevention efficiency and component lifespan. The rotation of the cleaning scraper under the gap fit breaks up the stagnant layer on the tube wall, improving heat exchange efficiency. Combined with turbulence, it reduces ion adhesion, making the heat transfer coefficient of the MVR system more stable. Energy consumption is lower than traditional equipment without a cleaning structure. The gap design is compatible with tiny suspended matter in landfill leachate, preventing the cleaning scraper from being stuck by impurities. It also reduces hard friction between the cleaning scraper and the tube wall, extending the service life of the heat exchange tube and cleaning components. Furthermore, it eliminates the need for frequent shutdowns for chemical cleaning, reducing cleaning agent consumption and labor costs. It also avoids heat exchange tube replacement due to scale corrosion, significantly reducing the overall life-cycle maintenance costs of the equipment. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a cross-sectional view of the evaporator body according to an embodiment of the present invention; Figure 3 This is a partial structural diagram of an embodiment of the present invention; Figure 4 This is a partial structural diagram of an embodiment of the present invention; Figure 5 This is a schematic diagram of the connection disk according to an embodiment of the present invention.
[0016] In the diagram: 1. Evaporator body; 2. Compressor; 3. Crystallizer; 4. Heat exchange tube assembly; 5. Rotary cleaning rod; 6. Cleaning scraper; 7. First shaft; 8. Second shaft; 9. Transmission gear; 10. Drive motor; 11. Connecting plate; 12. Gear ring; 13. Annular guide seat; 14. Annular guide block; 15. Baffle plate; 16. Support; 17. Circulating pump; 18. Gas-liquid separator; 19. Waste discharge pipe; 20. Raw liquid connection pipe. Detailed Implementation
[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] This embodiment discloses a method for treating landfill leachate by crystallization, comprising the following steps: Step a) Pretreatment: Through processes such as bar screens, sedimentation tanks, and ultrafiltration, solid suspended matter such as silt, flocculent matter, and garbage debris in the leachate is intercepted and separated to prevent large particles of impurities from entering the heat exchange tubes and clogging the heat exchange tube channels. Oil separation and air flotation are used to separate floating oil and emulsified oil in the leachate to prevent grease from adhering to the inner wall of the heat exchange tubes and forming an oil film, which would reduce heat transfer efficiency. Through oxidation, adsorption, or biochemical pretreatment, some recalcitrant large molecular organic matter is degraded or removed to reduce the coking and adhesion of organic matter on the tube wall during subsequent evaporation, further reducing the risk of scaling and reducing corrosion of equipment components. Step b: MVR evaporation and concentration. Start compressor 2 and circulation pump 17 to ensure continuous and stable flow of the pretreated leachate within the heat exchange tubes. Compressor 2 compresses and heats the secondary steam generated during evaporation, raising its saturation temperature above the boiling point of the leachate. The heated steam is then introduced into the heating chamber outside the heat exchange tubes to heat the leachate inside the tubes, achieving heat energy recycling and replacing traditional external heating sources. This significantly reduces evaporation energy consumption, aligning with the core advantage of low-energy operation in MVR technology and meeting the economic requirements of landfill leachate treatment. The high-temperature steam in the heating chamber exchanges heat with the leachate inside the tubes, causing the leachate to rapidly reach its boiling point and evaporate. Water is released as secondary steam, and the concentration of solutes such as salt and organic matter in the leachate continuously increases, concentrating the dilute leachate to a supersaturated state. This provides a high-concentration feed solution for subsequent crystallization and separation processes, achieving leachate reduction and salt enrichment. Step c, crystallization separation: The high-concentration leachate concentrate from the MVR evaporator is fed into crystallizer 3. By precisely controlling parameters such as the temperature (ideally 70-80℃) and vacuum level within crystallizer 3, the salts in the concentrate, such as sodium chloride and calcium carbonate, reach a supersaturated state, thus forming uniformly sized crystals. This completes the phase transition process from solute to crystals, converting dissolved salts into solid crystals, laying the foundation for subsequent salt separation and recovery. Simultaneously, it further reduces the volume of leachate, increasing the reduction rate. The crystal slurry from crystallizer 3 is then fed into a centrifuge or filter press for solid-liquid separation. The crystals are extracted from the mother liquor through solid-liquid separation, recovering salt crystals of acceptable purity. Depending on the salt content, these crystals can be used for industrial raw material regeneration or compliant disposal, avoiding the generation of high-salt hazardous waste. To improve the resource utilization level of landfill leachate treatment, the secondary steam generated during the crystallization process is transported to the inlet of compressor 2 of the MVR system through pipelines, where it is combined with the secondary steam generated by the evaporator body 1. After being compressed and heated by compressor 2, it is used as a heating source again and introduced into the heating chamber outside the heat exchange tube of the evaporator body 1. This maximizes the recovery of waste heat from the crystallization process, reduces the need for external heat source replenishment, and further reduces the overall energy consumption of the MVR system, meeting the process requirements of energy saving and consumption reduction. After the steam in the heating chamber completes heat exchange, it condenses into liquid water, which is collected by gas-liquid separator 18 and then transported to the condensate tank for collection. The condensate is then transported to the deep treatment unit for purification, so that the condensate water quality meets the reuse standard, realizing the recycling of water resources and reducing the consumption of fresh water in landfill leachate treatment. Step d: Preparation for heat exchanger tube cleaning. Real-time data such as pressure difference and heat transfer efficiency at the inlet and outlet of the heat exchanger tubes are collected through online monitoring modules, such as differential pressure sensors and heat transfer coefficient monitoring units, to determine the degree of scaling on the inner wall. Based on the scaling situation, the drive structure is activated accordingly, avoiding energy waste and ineffective wear of components caused by blind cleaning. This achieves intelligent operation and maintenance with on-demand cleaning, reducing system operating costs. The drive motor 10 drives the gear ring 12 and transmission gear 9 to rotate, which in turn drives the rotating cleaning rod 5 inside the heat exchanger tube to rotate at high speed. The cleaning scraper 6, with its gap fit design with the inner wall of the heat exchanger tube, precisely scrapes the residual scale layer attached to the tube wall during rotation. At the same time, it drives the fluid inside the tube to form a high-speed turbulent flow, flushing away the scale particles peeled off by the cleaning scraper 6. Through gap scraping, efficient cleaning is achieved. In addition to removing stubborn scale that is not completely removed during normal operation, this system avoids problems such as decreased heat transfer efficiency and pipe blockage caused by scale accumulation. The gap design prevents the cleaning scraper 6 from making hard contact with the tube wall, preventing deformation of the scraper 6 and scratches on the inner wall of the heat exchange tube. It also accommodates and removes scraped scale particles, eliminating jamming malfunctions. Online cleaning is achieved without disassembling the heat exchange tubes, significantly reducing downtime for maintenance and increasing the annual effective operating time of the equipment. After cleaning, the inner wall of the heat exchange tubes returns to a clean state, the heat transfer coefficient recovers to the normal range, and the fluid flow resistance decreases. This quickly restores the heat exchange efficiency and operational stability of the MVR evaporation and concentration stage, providing a continuous and stable high-concentration concentrate feed for the subsequent crystallization and separation stage, ensuring the continuity and reliability of the entire landfill leachate treatment process.
[0019] This invention also discloses a landfill leachate crystallization treatment device, including an evaporator body 1, a compressor 2, a crystallizer 3, and a supporting piping system. The evaporator body 1 contains a heat exchange tube assembly 4, such as... Figure 1 As shown in Figure 2, the evaporator body 1 is the core area for leachate evaporation and concentration. The internal heat exchange tube group 4 undertakes the key task of heat exchange. The compressor 2 is responsible for compressing and heating the secondary steam generated by evaporation, converting it into a recyclable heat source to achieve low-energy operation of the MVR system. The crystallizer 3 receives the high-concentration concentrated water output from the evaporator body 1 and completes the supersaturated precipitation of salt. The supporting pipeline system realizes the material and steam transportation between various equipment, constructing a complete closed-loop process of evaporation, compression and crystallization.
[0020] More specifically, each heat exchange tube in heat exchange tube assembly 4 is coaxially equipped with a rotating cleaning rod 5. A cleaning scraper 6 is embedded in the rotating cleaning rod 5 near the inner wall of the heat exchange tube. The outer edge of the cleaning scraper 6 is in clearance fit with the inner wall of the heat exchange tube. A first shaft 7 and a second shaft 8 are fixed to both ends of the rotating cleaning rod 5, as shown in Figures 2, 3, and 4. The coaxial arrangement of the rotating cleaning rod 5 with the heat exchange tube ensures that the clearance between the cleaning scraper 6 and the inner wall of the heat exchange tube is uniform during rotation, avoiding excessively large local clearances that could lead to scale insufficiency, or excessively small local clearances that could cause jamming and wear. The first shaft 7 and the second shaft 8 fixed to both ends of the rotating cleaning rod 5 are rotatably connected to the baffle 15 and the support 16 inside the evaporator, respectively, providing stable radial support for the rotating cleaning rod 5 and preventing scale buildup during high-speed rotation. The rotating cleaning rod 5, which is swaying and eccentric, is preferably one-quarter the diameter of the heat exchange tube, so as not to affect the normal transport of leachate. The cleaning scraper 6 is embedded in the tube wall near the rotating cleaning rod 5. Compared with the convex design, it can reduce the flow resistance of leachate and prevent the scraper from becoming an attachment point for suspended matter. At the same time, the embedded structure improves the connection strength between the cleaning scraper 6 and the rotating cleaning rod 5, adapting to the harsh operating environment of landfill leachate with high corrosion and high impurities. The gap between the cleaning scraper 6 and the inner wall of the heat exchange tube is preferably 0.1-0.5mm. The small gap of 0.1-0.5mm allows the cleaning scraper 6 to act directly on the initial scale layer on the inner wall of the heat exchange tube when rotating, scraping it off in real time and preventing the adhesion of hard scale such as calcium carbonate and calcium sulfate, solving the scaling problem from the source. For a small amount of stubborn scale layer generated during long-term operation.
[0021] A transmission gear 9 is fixedly connected to the top of the first shaft 7, a drive motor 10 is fixedly connected to the top of the outer shell of the evaporator body 1, a connecting plate 11 is fixedly connected to the output end of the drive motor 10, and a gear ring 12 that meshes with the transmission gear 9 is fixedly connected to the bottom of the connecting plate 11. Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, the transmission gear 9 at the top of the first shaft 7 meshes with the gear ring 12 at the bottom of the drive motor 10 connecting plate 11, realizing the synchronous drive of multiple rotating cleaning rods 5, ensuring consistent cleaning force for all heat exchange tubes, and improving the overall anti-scaling effect. By increasing the rotation speed of the rotating cleaning rods 5, the mechanical force of the cleaning scraper 6 can be used to peel off the scale. The clearance fit avoids hard contact between the cleaning scraper 6 and the tube wall, significantly reducing the wear rate of the cleaning scraper 6 and the inner wall of the heat exchange tube, extending the service life of the components. At the same time, the clearance can accommodate tiny suspended particles in the leachate that have not been fully pretreated. To prevent impurities from getting stuck between the cleaning scraper 6 and the tube wall, which could cause the rotating cleaning rod 5 to malfunction, the cleaning scraper 6 rotates while the rotating cleaning rod 5 rotates in a stepped manner. In conjunction with the cleaning scraper 6, the rotating rod 5 forms a screw conveyor-like structure during overall rotation, transporting the cleaned impurities and discharging them through the waste discharge pipe 19. The fluid velocity at the gap increases due to the cross-sectional contraction, creating strong local turbulence. Furthermore, the cleaning scraper 6 breaks up the stagnant layer on the inner wall of the heat exchange tube, accelerating the heat exchange between the permeate and the tube wall, improving the heat transfer efficiency of the MVR system, and reducing overall energy consumption.
[0022] Preferably, an annular guide seat 13 is fixedly connected inside the evaporator body 1 and rotatably connected to the shaft of the drive motor 10; an annular guide block 14, which is slidably engaged with the annular guide seat 13, is fixedly connected to the top of the connecting plate 11; a partition plate 15 is fixedly connected inside the evaporator body 1; a first shaft 7 is rotatably connected to the partition plate 15; a bracket 16 is fixedly connected inside the evaporator body 1; and a second shaft 8 is rotatably connected to the bracket 16. Figure 2 , Figure 3 and Figure 4 As shown, the annular guide seat 13 is rotatably connected to the shaft of the drive motor 10, providing radial positioning support for the connecting disk 11. The annular guide block 14 on the top of the connecting disk 11 is slidably engaged with the annular guide seat 13, which can limit the radial offset of the connecting disk 11 during rotation and prevent fluctuations in the meshing clearance between the gear ring 12 and the transmission gear 9. This structure can counteract the eccentric load generated when the drive motor 10 drives the gear ring 12 to rotate, ensuring that the gear ring 12 meshes evenly with the transmission gears 9 of all rotating cleaning rods 5, achieving synchronous and stable rotation of multiple rotating cleaning rods 5, and preventing uneven meshing. Due to localized gear wear or differences in the rotational speed of the cleaning rod, the baffle 15 inside the evaporator body 1 is rotatably connected to the first shaft 7, and the bracket 16 is rotatably connected to the second shaft 8, forming a double-end support structure for the rotating cleaning rod 5. This structure provides axial and radial double-limiting for the rotating cleaning rod 5, preventing it from shaking, shifting, or becoming eccentric during high-speed rotation. The double-end support design significantly improves the operational stability of the rotating cleaning rod 5, ensuring that the gap between the cleaning scraper 6 and the inner wall of the heat exchange tube remains uniform throughout the entire tube length, and avoiding excessively large or small local gaps due to eccentricity of the cleaning rod.
[0023] Finally, it also includes a circulating pump 17 and a gas-liquid separator 18. The input end of the circulating pump 17 is connected to the bottom of the evaporator body 1 via a pipe, and the input end of the circulating pump 17 is connected to the mother liquor outlet of the crystallizer 3 via a pipe. The exhaust port of the crystallizer 3 and the gas-liquid separator 18 are connected via a pipe, and the exhaust port of the gas-liquid separator 18 is connected to the input end of the compressor 2. A waste discharge pipe 19 is connected to the bottom of the evaporator body 1, and a raw liquid connection pipe 20 is connected to the connecting pipe between the circulating pump 17 and the evaporator. Figure 1 As shown, the input end of the circulating pump 17 is connected to the bottom of the evaporator body 1 and the crystallizer 3 respectively. On the one hand, it draws back the leachate in the evaporator that has not reached the concentration requirement, mixes it with the pretreated leachate added by the raw liquid pipe 20, and then re-enters the heat exchange tube for evaporation, realizing the circulation and concentration of the leachate to ensure that the final output concentration meets the crystallization requirements. On the other hand, it can return the mother liquor that has not been fully crystallized in the crystallizer 3 to the evaporator column to improve the salt recovery rate. By adjusting the flow rate of the circulating pump 17, the flow rate of the leachate in the heat exchange tube is precisely controlled. With the gap between the cleaning scraper 6 and the inner wall of the heat exchange tube, it can ensure that the turbulence formed by the rotation of the scraper enhances the heat transfer, while avoiding the increase in equipment resistance caused by excessive flow rate or the local scaling caused by excessive flow rate. The gas-liquid separator 18 and the crystallizer 3 exhaust gas. The gas-liquid separator 18, connected to the inlet, ensures that the secondary steam entering the compressor 2 is clean and dry, improving the compression efficiency of the compressor 2 and reducing energy consumption during the steam compression process. This aligns with the energy-saving core advantages of the MVR system. The waste discharge pipe 19 connects to the bottom of the evaporator body 1 and is used to periodically discharge small amounts of insoluble impurities and sludge deposited in the evaporator. This prevents impurities from accumulating at the bottom of the heat exchange tubes and from clogging the heat exchange tube inlet. It also reduces the risk of blockage caused by impurities coming into contact with the cleaning scraper 6. The raw liquid pipe 20 connects to the connection pipe between the circulation pump 17 and the evaporator. This is used to continuously replenish the pretreated fresh leachate. After mixing with the circulating liquid, the leachate enters the heat exchange tubes, maintaining a stable liquid level and concentration gradient in the evaporator body 1 and ensuring the continuity of the evaporation and concentration process.
[0024] It should be noted that parts have a lifespan and can be replaced during regular maintenance when they no longer meet performance requirements. Deterioration in performance due to prolonged use of parts is not a design defect of this application.
[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for treating landfill leachate by crystallization, characterized in that, Includes the following steps: Step a: Pretreatment, the landfill leachate is pretreated to remove suspended solids, grease and some organic matter; Step b: MVR evaporation and concentration. Start the compression device and circulation device. The pretreated leachate enters the heat exchange tube. The compression device compresses and heats the secondary steam and uses it as a heat source to heat the leachate. Step c: Crystallization and separation. The concentrated water is fed into the crystallization equipment for evaporation and crystallization. The crystallization product is separated and recovered. The secondary steam is recycled. The condensate is collected and further treated for reuse. Step d: Heat exchange tube cleaning preparation. Based on the scale buildup on the inner wall of the heat exchange tube, activate the drive mechanism to drive the cleaning mechanism to clean the inner wall of the heat exchange tube.
2. The method for crystallization treatment of landfill leachate according to claim 1, characterized in that: In step b, the flow rate of the leachate in the heat exchange tube is 1.0-1.5 m / s, and the evaporation temperature is controlled at 80-90℃.
3. The method for treating landfill leachate crystallization according to claim 1, characterized in that: In step c, the evaporation temperature of the crystallizer (3) is controlled at 70-80℃.
4. A landfill leachate crystallization treatment device, characterized in that, A method for treating landfill leachate crystallization according to any one of claims 1-3, comprising an evaporator body (1), a compressor (2), a crystallizer (3), and a supporting pipeline system, characterized in that: a heat exchange tube group (4) is provided inside the evaporator body (1), and a rotating cleaning rod (5) is coaxially arranged in each heat exchange tube of the heat exchange tube group (4), a cleaning scraper (6) is embedded in the surface of the rotating cleaning rod (5) close to the inner wall of the heat exchange tube, the outer edge of the cleaning scraper (6) is in clearance fit with the inner wall of the heat exchange tube, a first shaft (7) and a second shaft (8) are fixedly connected to both ends of the rotating cleaning rod (5), a transmission gear (9) is fixedly connected to the top of the first shaft (7), a drive motor (10) is fixedly connected to the top of the outer shell of the evaporator body (1), a connecting plate (11) is fixedly connected to the output end of the drive motor (10), and a gear ring (12) meshing with the transmission gear (9) is fixedly connected to the bottom of the connecting plate (11).
5. The landfill leachate crystallization treatment equipment according to claim 4, characterized in that: The evaporator body (1) is internally fixed with an annular guide seat (13) that is rotatably connected to the shaft of the drive motor (10), and the top of the connecting plate (11) is fixed with an annular guide block (14) that is slidably engaged with the annular guide seat (13).
6. The landfill leachate crystallization treatment equipment according to claim 4, characterized in that: The evaporator body (1) is internally fixed with a partition (15), the first shaft (7) is rotatably connected to the partition (15), and the evaporator body (1) is internally fixed with a bracket (16), the second shaft (8) is rotatably connected to the bracket (16).
7. The landfill leachate crystallization treatment equipment according to claim 4, characterized in that: It also includes a circulating pump (17) and a gas-liquid separator (18). The input end of the circulating pump (17) is connected to the bottom of the evaporator body (1) through a pipe, and the input end of the circulating pump (17) is connected to the mother liquor outlet of the crystallizer (3) through a pipe.
8. The landfill leachate crystallization treatment equipment according to claim 7, characterized in that: The exhaust port of the crystallizer (3) and the gas-liquid separator (18) are connected by a pipe, and the exhaust port of the gas-liquid separator (18) is connected to the input end of the compressor (2).
9. A landfill leachate crystallization treatment device according to claim 7, characterized in that: The bottom of the evaporator body (1) is connected to a waste discharge pipe (19), and the connecting pipe between the circulation pump (17) and the evaporator is connected to a raw liquid pipe (20).