High-salinity wastewater evaporation and concentration system and method with scale inhibition function

Abstract

The invention discloses a high-salinity wastewater evaporation and concentration system and method with a scale inhibition function, the system comprises an evaporation and concentration crystallizer, an outer circulation pipeline and a forced circulation pump arranged on the outer circulation pipeline, the evaporation and concentration crystallizer comprises an evaporation and concentration chamber at the upper part and a crystallization chamber at the lower part; a heat exchange coil and a rolling brush mechanism for cleaning the heat exchange coil are arranged in the evaporation concentration chamber, the crystallization chamber is internally divided into an overflow area and a crystallization area, a downcomer is also arranged in the crystallization chamber, the upper end of the downcomer is butted and communicated with the bottom of the evaporation concentration chamber, and the lower end of the downcomer extends into the lower part of the crystallization area; one end of the external circulation pipeline is connected with the evaporation concentration chamber, the other end is connected with the overflow area, and the external circulation pipeline is also provided with an electromagnetic induction heating system. A rolling brush mechanism is arranged in the evaporation concentration chamber, so that online cleaning of a heat exchange interface is realized. Under the action of an excitation electromagnetic field, homogeneous growth of salt ions in feed liquid on a solution crystal nucleus is promoted, and precipitation on a heat exchange heterogeneous interface is avoided.

Description

Technical Field

[0001] This invention relates to a high-salt wastewater evaporation and concentration system and method with scale inhibition function, which can be widely used in the zero-discharge treatment of high-salt wastewater at the end of coal-fired power plants, chemical and pharmaceutical industries. Background Technology

[0002] With the acceleration of industrialization, high-salinity wastewater (typically exceeding 1% total salt content) has become one of the core challenges restricting sustainable environmental development. Zero-discharge treatment is a crucial technology for achieving efficient separation and resource recovery of salt and water. Among these technologies, evaporation concentration and volume reduction are the most common and important steps in the zero-discharge treatment of high-salinity wastewater. However, high-salinity wastewater contains significant amounts of calcium... 2+ Mg 2 + SO42- and other ions are continuously concentrated during evaporation, leading to supersaturation and the formation of hard scale such as calcium sulfate and silicates. This scale adheres to the surface of the heat exchanger, causing a 40-60% decrease in the heat transfer coefficient. This severely affects the heat exchange effect and energy consumption, and poses a potential risk of equipment corrosion, greatly shortening the equipment's operation and maintenance cycle and service life.

[0003] To address the scaling problem during the evaporation process of high-salt wastewater, existing technologies mainly rely on chemical treatment (such as seed crystal method, scale inhibitor addition) or mechanical cleaning (high-pressure water jet, acid washing) to ensure the stable operation of the evaporator. However, the implementation process still faces multiple bottlenecks, such as high chemical costs (e.g., the cost of special scale inhibitors accounts for 15%-20% of the operating cost), lengthy process flow (requiring supporting pretreatment softening and multi-stage filtration units), and cumbersome cleaning steps (shutdown disassembly and cleaning takes more than 24 hours). Currently, there is a lack of inexpensive and effective evaporation concentration and volume reduction systems and methods with online scale inhibition functions. Summary of the Invention

[0004] This invention addresses the scaling problem in existing wastewater evaporation systems by proposing a high-salt wastewater evaporation and concentration system and method with scale inhibition function, which has the advantages of reducing descaling costs in wastewater evaporation heat exchangers and reducing dependence on scale inhibitors.

[0005] The technical solution adopted in this invention is as follows:

[0006] A high-salt wastewater evaporation and concentration system with scale inhibition function includes an evaporation and concentration crystallizer, an external circulation pipeline, and a forced circulation pump installed on the external circulation pipeline. The evaporation and concentration crystallizer includes an upper evaporation and concentration chamber and a lower crystallization chamber. The evaporation and concentration chamber is equipped with a heat exchange coil and a roller brush mechanism for cleaning the heat exchange coil. The interior of the crystallization chamber is divided into an overflow area and a crystallization area by an overflow plate. The crystallization chamber is also equipped with a downcomer, the upper end of which is connected to the bottom of the evaporation and concentration chamber, and the lower end extends into the lower part of the crystallization area.

[0007] One end of the external circulation pipeline is connected to the evaporation and concentration chamber, and the other end is connected to the overflow area. An electromagnetic induction heating system is also provided on the external circulation pipeline so that, under the action of the excitation electromagnetic field, salt ions in the feed liquid in the external circulation pipeline can grow homogeneously on the solution crystal nuclei.

[0008] A discharge port is provided at the bottom of the crystallization zone.

[0009] Furthermore, the heat exchange coil includes multiple layers of spaced coils and a main inlet pipe and an outlet pipe connecting all the coils; each layer of coil includes multiple concentric circular tubes located on the same horizontal plane, and the multiple concentric circular tubes are connected to each other by pipes.

[0010] Furthermore, the roller brush mechanism includes a drive motor, a stirring shaft, paddles, and roller brushes. The drive motor is located on the top of the evaporation and concentration crystallizer, and its output shaft is connected to the stirring shaft. The lower end of the stirring shaft extends vertically into the evaporation and concentration chamber and passes through the center of the heat exchange coil. Multiple horizontal paddles are fixedly installed on the side of the stirring shaft, and each paddle is fixedly equipped with a roller brush. The roller brushes and the heat exchange coils are arranged alternately. Under the drive of the drive motor, the roller brushes can form relative motion with the coils, thereby cleaning the coil interface online and preventing dirt from accumulating on the surface of the heat exchange coils, which would affect the heat exchange efficiency, thus extending the cleaning and maintenance cycle of the evaporation and concentration equipment.

[0011] Furthermore, the electromagnetic induction heating system includes an electromagnetic excitation coil and a variable frequency AC power supply. Two sections of electromagnetic excitation coil are wound on the external circulation pipeline. The two sections of electromagnetic excitation coil are located on the inlet and outlet pipelines of the forced circulation pump, respectively. The electromagnetic excitation coil is connected to the variable frequency AC power supply through wires. The variable frequency AC power supply provides a high-frequency oscillating sine wave signal to the electromagnetic excitation coil.

[0012] Furthermore, the length of each electromagnetic excitation coil segment is at least 0.5-1.5m.

[0013] Furthermore, it also includes a gas-liquid separator and a steam compressor. The top outlet of the evaporation and concentration chamber is connected to the inlet of the gas-liquid separator by a pipeline, and the bottom outlet of the gas-liquid separator is connected to the inlet of the evaporation and concentration chamber by a pipeline. The steam separated by the gas-liquid separator is pressurized and heated by the steam compressor and then input into the inlet of the heat exchange coil as its heating source.

[0014] Furthermore, it also includes a feed pump, a plate and frame heat exchanger, and a steam condensate tank. The outlet of the heat exchange coil is connected to the steam condensate tank through a pipeline, and the outlet of the steam condensate tank is connected to the hot channel of the plate and frame heat exchanger through a pipeline. The feed pump is used to input the high-salt wastewater to be evaporated and concentrated, and the outlet of the feed pump is connected to the evaporation and concentration chamber through the cold channel of the plate and frame heat exchanger.

[0015] A method for evaporating and concentrating high-salt wastewater with scale inhibition function is disclosed in this invention. The evaporation and concentration system described herein includes a pre-added crystal nucleus in the crystallization chamber of the evaporation and concentration crystallizer. High-salt wastewater is pumped into the evaporation and concentration chamber, where a heat exchange coil heats and concentrates the wastewater. The supersaturated solution after concentration enters the crystallization zone through a downcomer, where it mixes with the pre-added crystal nucleus and grows. The unsaturated solution after crystallization enters the overflow zone through an overflow plate. The solution in the overflow zone is output by a forced circulation pump and flows through the external circulation pipeline. Under the influence of an alternating oscillating magnetic field provided by an electromagnetic induction heating system, salt ions in the liquid in the external circulation pipeline grow homogeneously on the solution crystal nucleus before entering the evaporation and concentration chamber.

[0016] The crystal nuclei grown in the crystallization zone shown in the figure sink to the bottom of the crystallization zone under the action of gravity and are discharged to the subsequent processing device through the discharge port.

[0017] Furthermore, the electromagnetic induction heating system uses a high-frequency AC power supply to provide a high-frequency oscillating sine wave signal with a frequency of 10 to 100 kHz, and provides an alternating oscillating magnetic field strength of 0.1-0.5 T for the liquid fluid in the external circulation pipeline.

[0018] Furthermore, the forced circulation pump maintains high-speed flow of the liquid in the external circulation pipeline to enhance interfacial heat transfer. The flow velocity of the liquid in the external circulation pipeline is above 1.75 m / s, preferably 2-4 m / s. By utilizing the scouring effect of crystal particles in the solution on the inner wall of the heating tube, the formation of fouling is prevented to the greatest extent.

[0019] Furthermore, the main ionic composition of the high-salinity wastewater is as follows: sodium ions (0.3–2%), calcium ions (0.3–0.7%), magnesium ions (0.2–0.6%), chloride ions (1–3%), sulfate ions (0.2–0.4%), etc. The suspended solids (SS) concentration of the high-salinity wastewater is 5–10%.

[0020] Furthermore, the pre-added crystal nuclei are gypsum particles with a particle size of 50-100 μm, and their mass concentration in the solution in the evaporation and concentration crystallizer is 2-5%. Thus, the gypsum particles in the wastewater are used as seed crystals to guide the salt to precipitate under the action of an electromagnetic field, and the formed crystal particles flush the pipe wall to prevent scaling.

[0021] When the system of this invention is started for the first time or restarted after a major overhaul, a crystal nucleus needs to be added as a "start-up seed crystal". As the system runs, new calcium sulfate crystals will continuously precipitate as the wastewater becomes more concentrated. These newly generated crystals can replenish and replace the lost seed crystals, enabling the system to maintain a dynamic equilibrium. At this point, there is no need to add additional seed crystals.

[0022] Furthermore, the temperature of the liquid being heated in the evaporation and concentration chamber is controlled at 80–98°C.

[0023] Furthermore, the solid content of the concentrated wastewater mixed with precipitated salts and scale crystals in the crystallization zone is controlled within the range of 20-30%, and the wastewater concentration ratio is 5-10 times.

[0024] In the high-salt wastewater evaporation and concentration method of the present invention, the alternating magnetic field generated by the electromagnetic excitation coil propagates throughout the entire system along the material fluid medium and forms eddy current in the high-salt wastewater to achieve further heating. This promotes the homogeneous formation of scale microcrystals by positive ions such as calcium and magnesium and negative ions such as calcium sulfate and calcium carbonate in the solution, which are then carried away by the water flow, preventing them from crystallizing and precipitating on the heat exchanger wall surface, thereby reducing the occurrence of scale formation in the heat exchanger.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] (1) A low-cost and effective evaporation concentration and volume reduction system with online scale inhibition function is provided for high-salt wastewater, so as to realize the resource utilization of wastewater;

[0027] (2) The present invention features a roller brush mechanism installed in the evaporation and concentration chamber, enabling online cleaning of the heat exchange interface. Under the action of an excitation electromagnetic field, the salt ions in the feed solution are homogeneously grown on the solution crystal nuclei, preventing precipitation at the heterogeneous heat exchange interface. Forced circulation maintains the liquid flow rate in the evaporation and concentration chamber of the evaporation and concentration crystallizer, promoting continuous scouring of the carried microcrystals, thereby enhancing interfacial heat transfer and cleaning the heat exchange tube walls.

[0028] (3) This invention enhances the system's online scale inhibition capability by effectively combining a roller brush mechanism and electromagnetic scale inhibition, effectively reducing the use of chemical agents such as scale inhibitors and cleaning agents, lowering maintenance costs, and simplifying the operation process. This invention combines multiple physical scale inhibition technologies, reducing the use of chemical scale inhibitors and minimizing scaling problems during evaporation and concentration.

[0029] (4) No additional seed crystals are needed. The variable frequency electromagnetic field accelerates the homogeneous generation of seed crystals in the wastewater, which serve as solid cores to guide and control the directional crystallization of scale ions in the solution, thereby minimizing the nucleation and precipitation on the heat exchanger surface. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the high-salt wastewater evaporation and concentration system of the present invention;

[0031] In the diagram: 1. Feed pump, 2. Plate and frame heat exchanger, 3. Steam condensate tank, 4. Evaporation and concentration crystallizer, 41. Drive motor, 42. Roller brush, 43. Heat exchange coil, 44. Downcomer, 45. Crystallization zone, 46. Overflow zone, 47. Discharge port, 5. Electromagnetic excitation coil, 6. Variable frequency AC power supply, 7. Forced circulation pump, 8. Gas-liquid separator, 9. Steam compressor. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0033] Example: Comparison Figure 1

[0034] A high-salt wastewater evaporation and concentration system with scale inhibition function includes a feed pump 1, a plate and frame heat exchanger 2, an electromagnetic excitation coil 5, a variable frequency AC power supply 6, an evaporation and concentration crystallizer 4, an external circulation pipeline, a forced circulation pump 7, a gas-liquid separator 8, a steam compressor 9, and a steam condensate tank 3.

[0035] The evaporation-concentration crystallizer 4 includes an upper evaporation-concentration chamber and a lower crystallization chamber. The evaporation-concentration chamber is equipped with a heat exchange coil 43 and a roller brush mechanism for cleaning the heat exchange coil 43. The crystallization chamber is divided into an overflow zone 46 and a crystallization zone 45 by an overflow plate. A downcomer 44 is also installed in the crystallization chamber, with its upper end connected to the bottom of the evaporation-concentration chamber and its lower end extending into the lower part of the crystallization zone 45. One end of an external circulation pipeline is connected to the evaporation-concentration chamber, and the other end is connected to the overflow zone 46. A discharge port 47 is provided at the bottom of the crystallization zone 45.

[0036] The heat exchange coil 43 includes multiple layers of spaced coils and a liquid inlet manifold and a liquid outlet manifold connecting all the coils; each layer of coil includes multiple concentric circular tubes located on the same horizontal plane, and the multiple concentric circular tubes are connected to each other by pipes.

[0037] The roller brush mechanism includes a drive motor 41, a stirring shaft, paddles, and roller brushes 42. The drive motor 41 is mounted on top of the evaporator-concentrator-crystallizer 4. The output shaft of the drive motor 41 is connected to the stirring shaft. The lower end of the stirring shaft extends vertically into the evaporator-concentrator chamber and passes through the center of the heat exchange coil 43. Multiple horizontal paddles are fixedly arranged at intervals from top to bottom on the side of the stirring shaft, and each paddle is fixedly equipped with a roller brush 42. The roller brushes 42 and the heat exchange coils 43 are arranged alternately. Driven by the drive motor 41, the roller brushes 42 can form relative motion with the coils, thereby cleaning the coil interface online and preventing dirt from accumulating on the surface of the heat exchange coils, which would affect the heat exchange efficiency and extend the cleaning and maintenance cycle of the evaporator-concentrator.

[0038] Comparison Figure 1 Two electromagnetic excitation coils 5 are wound on the external circulation pipeline. The two electromagnetic excitation coils 5 are located on the inlet and outlet pipelines of the forced circulation pump 7, respectively. The electromagnetic excitation coils 5 are connected to the frequency converter AC power supply 6 through wires. The frequency converter AC power supply 6 provides the electromagnetic excitation coils 5 with a high-frequency oscillating sine wave signal.

[0039] Raw water from the mother liquor buffer tank is pumped by feed pump 1 to plate and frame heat exchanger 2, where it exchanges heat with the exothermic steam condensate in steam condensate tank 3. It is then sent to the evaporation and concentration chamber of evaporation and concentration crystallizer 4. In the evaporation and concentration chamber, heat exchange coil 43 heats the raw water. The generated secondary steam is first sent to gas-liquid separator 8 for gas-liquid separation. The separated liquid is then returned to the evaporation and concentration chamber, while the separated gas is pressurized and heated by steam compressor 9 before being sent back to heat exchange coil 43 as its heating source. The fluid that has undergone heat exchange in heat exchange coil 43 is then sent to steam condensate tank 3. The supersaturated solution concentrated in the evaporation and concentration chamber flows down the downcomer 44 into the crystallization chamber below, where it mixes with the crystal nuclei in the mother liquor and grows in the crystallization zone 45. The volume of the crystallization zone is large enough that the unsaturated solution after crystallization is discharged through the overflow zone 4-6 and pumped back into the evaporation and concentration chamber by the forced circulation pump 7. The grown crystal nuclei settle to the bottom of the crystallization zone under gravity and are discharged to the subsequent processing device through the discharge port 4-7.

[0040] In the system of this invention, the heat exchange coil 43 is the main source of heating for evaporation and concentration. In comparison, the heat provided by electromagnetic induction heating is much smaller. The main purpose of electromagnetic induction heating is to promote the homogeneous growth of salt ions in the feed solution on the crystal nuclei of the solution under the action of an excited electromagnetic field.

[0041] The alternating magnetic field generated by the electromagnetic excitation coil 5 propagates throughout the entire system along the material fluid medium, promoting the homogeneous formation of scale microcrystals by positive ions such as calcium and magnesium in the water and negative ions such as calcium sulfate and calcium carbonate in the solution, which are then carried away by the water flow, preventing them from crystallizing and precipitating on the heat exchange wall surface, thereby reducing scaling in the evaporation and concentration chamber.

[0042] Example 1:

[0043] A method for evaporating and concentrating high-salt wastewater with scale inhibition function, employing, for example... Figure 1The evaporation and concentration system shown has crystal nuclei pre-added in the crystallization chamber. High-salt wastewater is pumped into the evaporation and concentration chamber, and the heat exchange coil 43 heats and concentrates the high-salt wastewater. The concentrated supersaturated solution enters the crystallization zone 45 through the downcomer 44, mixes with the pre-added crystal nuclei, and grows in the crystallization zone. The unsaturated solution after crystallization enters the overflow zone 46 through the overflow plate. The solution in the overflow zone 46 is output by the forced circulation pump 7. During the flow through the external circulation pipeline, under the action of the alternating oscillating magnetic field provided by the electromagnetic excitation coil 5, the salt ions in the feed liquid in the external circulation pipeline grow homogeneously on the solution crystal nuclei, and then enter the evaporation and concentration chamber.

[0044] The crystal nuclei grown in the crystallization zone 45 shown in the figure sink to the bottom of the crystallization zone under the action of gravity and are discharged to the subsequent processing device through the discharge port 47.

[0045] Two electromagnetic excitation coils 5 are wound on the external circulation pipeline where the forced circulation pump 7 is located. The two electromagnetic excitation coils 5 are located on the inlet and outlet pipelines of the forced circulation pump 7, respectively, and each electromagnetic excitation coil 5 is 1.2m long. The high-frequency AC power supply 6 provides a high-frequency oscillating sine wave signal with a frequency of 50kHz, and provides an alternating oscillating magnetic field strength of 0.3T for the liquid fluid in the external circulation pipeline.

[0046] The forced circulation pump 7 promotes high-speed flow of the liquid in the evaporation and concentration chamber, with a material flow rate of 2.85 m / s to enhance interfacial heat transfer. At the same time, the scouring effect of the crystal particles in the solution on the inner wall of the heating tube is used to minimize the formation of fouling.

[0047] The main ionic composition of the high-salinity wastewater raw water used in the experiment of Example 1 of this invention is as follows: sodium ions (about 1.1%), calcium ions (about 0.5%), magnesium ions (about 0.4%), chloride ions (about 2%), and sulfate ions (about 0.3%). The suspended solids (SS) concentration of the raw water is in the range of 7%.

[0048] The pre-added crystal nuclei are gypsum particles with a particle size of 50-100 μm. Their mass concentration in the solution within the evaporation and concentration crystallizer is 3%. These gypsum particles in the wastewater act as seed crystals, guiding salt precipitation under the influence of an electromagnetic field. The resulting crystal particles then flush the pipe walls to prevent scaling. The temperature of the feed liquid in the evaporation and concentration chamber is controlled at 90°C.

[0049] When the system in Embodiment 1 of the present invention is running stably, the experimental results of continuous treatment are as follows: after being processed by the evaporation, concentration and crystallization device 4, the concentrated wastewater mixed with precipitated salt and scale crystals is discharged through the outlet 4-7, and its solid content is controlled at 27%, and the concentration ratio of the wastewater is 8 times.

[0050] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A high-salinity wastewater evaporation and concentration system with scale inhibition function, characterized in that... The system includes an evaporation and concentration crystallizer (4), an external circulation pipeline, and a forced circulation pump (7) installed on the external circulation pipeline. The evaporation and concentration crystallizer (4) includes an upper evaporation and concentration chamber and a lower crystallization chamber. The evaporation and concentration chamber is equipped with a heat exchange coil (43) and a roller brush mechanism for cleaning the heat exchange coil (43). The interior of the crystallization chamber is divided into an overflow area (46) and a crystallization area (45) by an overflow plate. A downcomer (44) is also installed in the crystallization chamber. The upper end of the downcomer (44) is connected to the bottom of the evaporation and concentration chamber, and the lower end extends into the lower part of the crystallization area (45). One end of the external circulation pipeline is connected to the evaporation and concentration chamber, and the other end is connected to the overflow area (46). An electromagnetic induction heating system is also provided on the external circulation pipeline so as to promote the homogeneous growth of salt ions in the liquid in the external circulation pipeline on the solution crystal nuclei under the action of the excitation electromagnetic field. The bottom of the crystallization zone (45) is provided with a discharge port (47).

2. The high-salinity wastewater evaporation and concentration system with scale inhibition function as described in claim 1, characterized in that... The heat exchange coil (43) includes multiple layers of spaced coils and a liquid inlet manifold and a liquid outlet manifold connecting all the coils; each layer of coil includes multiple concentric circular tubes located on the same horizontal plane, and the multiple concentric circular tubes are connected to each other by pipes.

3. The high-salt wastewater evaporation and concentration system with scale inhibition function as described in claim 2, characterized in that... The roller brush mechanism includes a drive motor (41), a stirring shaft, paddles, and roller brushes (42). The drive motor (41) is located on the top of the evaporation and concentration crystallizer (4). The output shaft of the drive motor (41) is connected to the stirring shaft. The lower end of the stirring shaft extends vertically into the evaporation and concentration chamber and passes through the center of the heat exchange coil (43). Multiple horizontal paddles are fixedly installed on the side of the stirring shaft, and each paddle is fixedly equipped with a roller brush (42). The roller brushes (42) and the coils of the heat exchange coil (43) are arranged alternately. Under the driving action of the drive motor (41), the roller brushes (42) can form relative motion with the coils, thereby cleaning the coil interface online.

4. The high-salinity wastewater evaporation and concentration system with scale inhibition function as described in claim 1, characterized in that... The electromagnetic induction heating system includes an electromagnetic excitation coil (5) and a variable frequency AC power supply (6). Two sections of electromagnetic excitation coil (5) are wound on the external circulation pipeline. The two sections of electromagnetic excitation coil (5) are located on the inlet and outlet pipelines of the forced circulation pump (7), respectively. The electromagnetic excitation coil (5) is connected to the variable frequency AC power supply (6) through a wire. The variable frequency AC power supply (6) provides a high-frequency oscillating sine wave signal to the electromagnetic excitation coil (5).

5. A high-salinity wastewater evaporation and concentration system with scale inhibition function as described in claim 4, characterized in that... Each segment of the electromagnetic excitation coil (5) has a length of at least 0.5-1.5 m.

6. The high-salinity wastewater evaporation and concentration system with scale inhibition function as described in claim 1, characterized in that... It also includes a gas-liquid separator (8) and a steam compressor (9). The top outlet of the evaporation and concentration chamber is connected to the inlet of the gas-liquid separator (8) by a pipeline. The bottom outlet of the gas-liquid separator (8) is connected to the inlet of the evaporation and concentration chamber by a pipeline. The steam separated by the gas-liquid separator (8) is pressurized and heated by the steam compressor and then input into the inlet of the heat exchange coil (43) as its heating source.

7. A high-salinity wastewater evaporation and concentration system with scale inhibition function as described in claim 6, characterized in that... It also includes a feed pump (1), a plate and frame heat exchanger (2) and a steam condensate tank (3). The outlet of the heat exchange coil (43) is connected to the steam condensate tank (3) through a pipeline. The outlet of the steam condensate tank (3) is connected to the hot channel of the plate and frame heat exchanger (2) through a pipeline. The feed pump (1) is used to input the high-salt wastewater to be evaporated and concentrated. The outlet of the feed pump (1) is connected to the evaporation and concentration chamber through the cold channel of the plate and frame heat exchanger (2).

8. A method for evaporating and concentrating high-salinity wastewater with scale inhibition function, characterized in that... Using the evaporation and concentration system described in claim 1, crystal nuclei are pre-added in the crystallization chamber of the evaporation and concentration crystallizer; high-salt wastewater is pumped into the evaporation and concentration chamber, and the heat exchange coil (43) heats and concentrates the high-salt wastewater. The supersaturated solution after concentration enters the crystallization zone (45) through the downcomer (44), mixes with the pre-added crystal nuclei, and grows in the crystallization zone. The unsaturated solution after crystallization enters the overflow zone (46) through the overflow plate. The solution in the overflow zone (46) is output under the action of the forced circulation pump (7). During the process of flowing through the external circulation pipeline, under the action of the alternating oscillating magnetic field provided by the electromagnetic induction heating system, the salt ions in the feed liquid in the external circulation pipeline grow homogeneously on the solution crystal nuclei, and then enter the evaporation and concentration chamber. The crystal nuclei grown in the crystallization zone (45) shown in the figure sink to the bottom of the crystallization zone under the action of gravity and are discharged to the subsequent processing device through the discharge port (47).

9. The method for evaporating and concentrating high-salt wastewater with scale inhibition function as described in claim 8, characterized in that... The electromagnetic induction heating system uses a high-frequency AC power supply to provide a high-frequency oscillating sine wave signal with a frequency of 10~100 kHz. The alternating oscillating magnetic field strength provided to the liquid fluid in the external circulation pipeline is 0.1-0.5 T. The flow velocity of the liquid in the external circulation pipeline is above 1.75 m / s, preferably 2-4 m / s.

10. The method for evaporating and concentrating high-salt wastewater with scale inhibition function as described in claim 8, characterized in that... The suspended solids (SS) concentration in the high-salt wastewater ranges from 5% to 10%, and the pre-added crystal nuclei are gypsum particles with a particle size of 50 to 100 μm, and their mass concentration in the solution in the evaporator-concentrator-crystallizer is 2% to 5%. The temperature of the liquid being heated in the evaporation and concentration chamber is controlled at 80~98℃; The solid content of the concentrated wastewater mixed with precipitated salts and scale crystals in the crystallization zone (45) is controlled in the range of 20-30%, and the wastewater concentration ratio is 5-10 times.

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