Online cleaning high-salinity wastewater evaporation system based on closed cycle evaporation technology

Abstract

The application provides an online cleaning high-salt wastewater evaporation system based on a closed cycle evaporation technology, which comprises an evaporation tower, a circulating tank, a drainage pipeline and a pump water pipeline; a plurality of surface evaporators are arranged in the evaporation tower from top to bottom, and corresponding nozzles are arranged above each layer of surface evaporators; a plurality of guide channels are uniformly distributed on the peripheral wall of the circulating tank, and a guide inner cylinder is arranged in the circulating tank; the drainage pipeline is connected with the evaporation tower and all the guide channels; the pump water pipeline comprises a first pump water pipeline and a second pump water pipeline; the first pump water pipeline and the second pump water pipeline are both connected with the guide inner cylinder, the outlet end of the first pump water pipeline is connected with all the nozzles located in the uppermost layer, and the outlet end of the second pump water pipeline is provided with a plurality of pump water branch lines which can be independently controlled to be turned on or turned off and are connected with all the nozzles of the corresponding layer. The application realizes the staged and collaborative operation of the evaporation system, and the whole process does not need to be stopped and does not produce additional cleaning wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an online cleaning system for high-salt wastewater based on closed-loop evaporation technology. Background Technology

[0002] With the rapid development of fine chemicals (such as dyes, pesticide intermediates, and pharmaceutical intermediates), coal chemicals, and seawater utilization, the demand for evaporation and concentration treatment of high-salinity wastewater is increasing. Closed-cycle evaporation (CCE) technology, due to its features such as reverse Carnot cycle closed-loop energy recovery, dual-path heat recovery, and cold-end heat balance, has shown application potential in high-salinity wastewater treatment. Its working principle is as follows: high-salinity wastewater is sprayed onto the surface evaporator (heat pump condenser) inside the evaporation tower, where it absorbs heat and evaporates. The air inside the evaporation tower, with its humidity approaching saturation, is circulated through a wind path to the condensation tower (heat pump evaporator), where it releases heat and condenses, releasing liquid water and recovering latent heat for the next round of evaporation.

[0003] In practical applications, the heat source temperature of the surface evaporator (coil structure) does not exceed 65℃, and the evaporation temperature does not exceed 55℃. The upper part of the evaporator experiences greater spray scouring force, making it difficult for crystals to adhere; however, the middle and lower parts, farther from the nozzles, have significantly weaker scouring force, allowing crystals precipitated from wastewater evaporation to gradually accumulate on the coil surface, leading to a decrease in heat exchange capacity and ultimately disrupting the thermal balance of the CCE system. Currently, to restore heat exchange capacity, the surface evaporator surface is typically cleaned periodically with system permeate (evaporation effluent). However, this method has significant drawbacks: firstly, it requires system shutdown, affecting the continuity of system operation; secondly, the wastewater generated during cleaning needs to be returned to the CCE system for reprocessing, increasing the processing burden.

[0004] Therefore, how to effectively prevent or remove the crystals adhering to the lower part of the surface evaporator while ensuring continuous system operation, and at the same time avoid introducing external water sources or generating new cleaning wastewater, has become a key challenge restricting the efficient and stable operation of CCE technology. Summary of the Invention

[0005] To address the technical problems existing in the background art, this invention proposes an online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology.

[0006] This invention proposes an online cleaning system for high-salt wastewater based on closed-loop evaporation technology, comprising: an evaporation tower and a circulation tank, as well as drainage pipes and pump water pipes, wherein: The evaporation tower has a circulating air inlet, a circulating air outlet, and a drain outlet; the evaporation tower has multiple layers of surface evaporators arranged from top to bottom, and corresponding nozzles are arranged above each layer of surface evaporators; The circulating tank adopts a circular conical bottom structure and has a concentrate outlet at the bottom. The circumferential wall of the circulating tank has several guide channels with the same outlet orientation and tangent to the inner wall surface of the tank. The interior of the circulating tank has a vertically arranged inner guide cylinder, and the height of the lower end of the inner guide cylinder is not lower than the height of the outlet of the guide channel. The inlet end of the drainage pipe is connected to the drain outlet of the evaporator, and its outlet end is connected to all the flow guiding channels respectively. The water pumping pipeline includes a first water pumping pipeline and a second water pumping pipeline. The inlet ends of both the first and second water pumping pipelines are connected to the inner cylinder for drainage. The outlet end of the first water pumping pipeline is connected to all the nozzles located on the uppermost layer. The outlet end of the second water pumping pipeline is provided with multiple water pumping branches that can be independently controlled to open and close. Each water pumping branch corresponds to a layer of nozzles and is connected to all the nozzles in the corresponding layer.

[0007] Preferably, the first pumping water pipeline is configured to be normally open; the second pumping water pipeline is configured to be intermittently open and closed, and when the second pumping water pipeline is open, each pumping water branch in the second pumping water pipeline is opened sequentially from top to bottom in an intermittent manner.

[0008] Preferably, it further includes a first temperature sensor and a second temperature sensor; wherein, the first temperature sensor is used to monitor the refrigerant temperature at the inlet of the uppermost surface evaporator; the second temperature sensor is used to monitor the refrigerant temperature at the inlet of the remaining surface evaporators; the first water pumping pipeline controls its pumping volume according to the monitoring result of the first temperature sensor; the second water pumping pipeline controls its on / off state according to the difference between the temperature measured by the second temperature sensor and the temperature measured by the first temperature sensor.

[0009] Preferably, the pumps in both the first and second pumping water pipelines are variable frequency pumps; each pumping branch is controlled by a control valve installed in its pipeline; both the variable frequency pumps in the first and second pumping water pipelines are equipped with control units; wherein, the control unit of the variable frequency pump in the first pumping water pipeline is electrically connected to the first temperature sensor, and the control unit is configured to: when the monitoring data of the first temperature sensor is greater than a preset value, control the speed of the variable frequency pump in the first pumping water pipeline to increase; the control unit of the variable frequency pump in the second pumping water pipeline is electrically connected to the first and second temperature sensors, as well as the control valves in all pumping water branches, and the control unit is configured to: when the temperature measured by the second temperature sensor is higher than the temperature measured by the first temperature sensor, and the difference between the two is greater than a preset value, control the variable frequency pump in the second pumping water pipeline to start, and control the control valves in each pumping water branch to open sequentially from top to bottom in an intermittent manner.

[0010] Preferably, a first flow sensor is provided in the first water pumping pipeline; a second flow sensor is provided in the second water pumping pipeline; the control unit configured in the variable frequency pump in the second water pumping pipeline is also electrically connected to the first flow sensor and the second flow sensor respectively, and controls the water pumping volume of the second water pumping pipeline according to the data measured by the first flow sensor, so that the data measured by the second flow sensor is consistent with the data measured by the first flow sensor.

[0011] Preferably, it further includes a wastewater delivery pipeline connected to the circulation tank for delivering wastewater to be treated to the circulation tank, and a liquid level sensor installed on the circulation tank for monitoring the liquid level height inside the circulation tank; wherein, the wastewater delivery pipeline is configured to: control its delivery volume according to the monitoring data of the liquid level sensor so that the liquid level height inside the circulation tank is maintained within a preset value range; and stop delivery when the frequency of the variable frequency pump in the first pump pipeline is at its maximum value and the temperature measured by the first temperature sensor continues to rise.

[0012] Preferably, a baffle plate is provided inside the circulation tank and below the inner cylinder of the flow guide, which is coaxially arranged with the inner cylinder of the flow guide and maintains an axial distance, and the outer edge of the baffle plate extends radially to the outside of the inner cylinder of the flow guide.

[0013] Preferably, the baffle is circular, and its upper surface is a conical apex.

[0014] Preferably, it also includes a mixer; the mixer is fixedly installed on the top of the circulation tank, its mixing shaft is located inside the inner cylinder of the flow guide, and the mixing blade is located between the lower end of the inner cylinder of the flow guide and the upper end of the baffle plate, and the cross-sectional area of ​​the rotational envelope of the mixing blade is larger than the port diameter of the lower end of the inner cylinder of the flow guide, and is located inside the outer edge contour of the baffle plate; the blade of the mixing blade has an arc-shaped structure that is bent around the mixing shaft, the convex surface of the blade faces its rotation direction, and the rotation direction is consistent with the tangential direction of the flow guide channel.

[0015] Preferably, the surface of the surface evaporator is coated with a Teflon coating.

[0016] In this invention, the first pump water line continuously delivers relatively clear wastewater to the topmost first nozzle, uniformly spraying all surface evaporators to ensure continuous evaporation operation. Simultaneously, addressing the issue of lower evaporators easily adhering to crystalline salts due to their greater distance and weaker rinsing force, the second pump water line is activated as needed. By sequentially opening the first and second pump water branches, precise and individual rinsing is performed on each lower surface evaporator, effectively removing localized crystalline salts and preventing salt accumulation from affecting evaporation efficiency. This design achieves hierarchical coordinated operation of the evaporation system without requiring system shutdown or generating additional cleaning wastewater. It balances overall evaporation stability with localized cleaning and maintenance, effectively improving the continuous operation capability and anti-scaling performance of the evaporation system while ensuring effective cleaning. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology proposed in this invention; Figure 2 This is a schematic diagram of the tangential direction of the flow channel and the rotation direction of the stirring blades in an online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology proposed in this invention. Detailed Implementation

[0018] Reference Figure 1-2 The present invention proposes an online cleaning high-salt wastewater evaporation system based on closed-loop circulation evaporation technology, comprising: evaporation tower 1, circulation tank 2, drainage pipeline 9, pump water pipeline and wastewater conveying pipeline.

[0019] Evaporation tower 1 is a vertical cylindrical container (such as a cylindrical or square tube). A circulating air inlet is located near the bottom of its side wall, a circulating air outlet is located at the top, and a drain outlet is located at the center of the bottom. Multiple layers of surface evaporators 3 are arranged inside the evaporation tower 1 from top to bottom. In this embodiment, the surface evaporators 3 are coil-type surface evaporators, and there are three layers, from top to bottom: a first surface evaporator 31, a second surface evaporator 32, and a third surface evaporator 33. A nozzle 4 is correspondingly located directly above each layer of surface evaporators 3, specifically including: a first nozzle 41 located above the first surface evaporator 31, a second nozzle 42 located above the second surface evaporator 32, and a third nozzle 43 located above the third surface evaporator 33.

[0020] Wastewater conveying pipeline 7 is connected to circulation tank 2 and is used to convey wastewater to be treated into circulation tank 2. Circulation tank 2 is located below evaporation tower 1, adopts a circular conical bottom structure, and has a concentrate outlet at the bottom. Multiple guide channels 5 are evenly arranged circumferentially on the side wall of circulation tank 2. The outlet direction of each guide channel 5 is tangent to the inner wall surface of circulation tank 2, and the outlet directions of all guide channels 5 are consistent (both clockwise or counterclockwise tangential). A vertically arranged inner guide cylinder 6 is provided inside circulation tank 2. The lower end of the inner guide cylinder 6 is at a height not lower than the outlet height of each guide channel 5; in this embodiment, they are at the same horizontal level. Two outlets are provided on the side wall of the inner guide cylinder 6, namely the first outlet and the second outlet.

[0021] The inlet of the drainage pipe 9 is connected to the drain outlet of the evaporator 1, and its outlet is connected to all the guide channels 5. During operation, the concentrated wastewater discharged from the evaporator 1 is discharged into each guide channel 5 through the drainage pipe 9, and under the guidance of each guide channel 5, it enters the circulation tank 2 tangentially along the inner wall of the circulation tank 2, thereby driving the wastewater in the tank to form a hydraulic vortex. Under the action of the hydraulic vortex, the concentrated wastewater, whose density is greater than that of water, moves towards the inner wall of the circulation tank 2 due to centrifugal force and settles along the conical inner wall to the bottom conical section; the relatively clarified wastewater automatically collects in the inner guide cylinder 6.

[0022] The water pumping pipeline 8 includes a first water pumping pipeline 81 and a second water pumping pipeline 82. The inlet ends of both the first water pumping pipeline 81 and the second water pumping pipeline 82 are connected to the inner cylinder 6. The outlet end of the first water pumping pipeline 81 is connected to all the nozzles 4 located at the top layer. The outlet end of the second water pumping pipeline 82 is provided with two independently controllable water pumping branches 821, namely the first water pumping branch 821-1 and the second water pumping branch 821-2. The first water pumping branch 821-1 is connected to all the second nozzles 42, and the second water pumping branch 821-2 is connected to all the third nozzles 43.

[0023] During operation, the relatively clear wastewater inside the inner cylinder 6 is transported by the first water pump line 81 to the uppermost nozzle 4 (i.e., the first nozzle 41), so that the wastewater is sprayed onto all surface evaporators 3 to ensure continuous evaporation. At the same time, when other surface evaporators 3 on the lower level are far from the first nozzle 41 and receive less scouring force, and crystalline salts adhere to their surfaces, the second water pump line 82 is opened, and the other surface evaporators 3 are individually flushed by sequentially opening the first water pump branch 821-1 and then the second water pump branch 821-2.

[0024] Specifically, the first pump water pipeline 81 is configured to be normally open; the second pump water pipeline 82 is configured to be intermittently open and closed, and when the second pump water pipeline 82 is open, the first pump water branch 821-1 and the second pump water branch 821-2 in the second pump water pipeline 82 are sequentially opened one at a time from top to bottom, as follows: Step 1: Turn on the first pump water branch 821-1 so that the second nozzle 42 sprays and washes the second surface evaporator 32.

[0025] Step 2: Close the first water pump branch 821-1, and when the interval reaches the preset value, open the second water pump branch 821-2 so that the third nozzle 43 sprays and washes the third surface evaporator 33.

[0026] This design avoids insufficient flow and pressure caused by all nozzles 4 working at the same time, reduces energy consumption, and ensures that the surface of each layer of surface evaporator 3 can be effectively cleaned.

[0027] In addition, this system is equipped with a first temperature sensor and a second temperature sensor. The first temperature sensor is used to monitor the refrigerant temperature at the inlet of the first surface evaporator 31; the second temperature sensor is used to monitor the refrigerant temperature at the inlet of the second surface evaporator 32 and the third surface evaporator 33. Specifically, the second surface evaporator 32 and the third surface evaporator 33 share the same refrigerant inlet, and the second temperature sensor is installed at the shared refrigerant inlet to monitor the refrigerant temperature at that inlet.

[0028] The first water pump line 81 controls its pumping volume based on the monitoring results of the first temperature sensor. During operation, when the first temperature sensor detects that the surface temperature of the first surface evaporator 31 exceeds a preset value, the first water pump line 81 increases the unit pumping volume to ensure that the inlet refrigerant of the first surface evaporator 31 is within the preset range.

[0029] The second water pump line 82 controls its on / off state based on the temperature difference between the second temperature sensor and the first temperature sensor. During operation, when the temperature measured by the second temperature sensor is higher than that measured by the first temperature sensor, and the difference between the two is greater than a preset value, it indicates that there is significant scaling on the surfaces of the second and third surface evaporators 32 and 33 monitored by the second temperature sensor, resulting in reduced heat exchange efficiency. At this time, the second water pump line 82 is opened to flush the corresponding second and third surface evaporators 32 and 33.

[0030] The specific structure is configured as follows: the pumps in the first pumping water pipeline 81 and the second pumping water pipeline 82 are both variable frequency pumps; each pumping water branch 821 is controlled by a control valve installed in its pipeline; both the variable frequency pumps in the first pumping water pipeline 81 and the second pumping water pipeline 82 are equipped with control units; wherein, the control unit of the variable frequency pump in the first pumping water pipeline 81 is electrically connected to the first temperature sensor, and the control unit is configured to: when the monitoring data of the first temperature sensor is greater than a preset value, control the speed of the variable frequency pump in the first pumping water pipeline 81 to increase; the control unit of the variable frequency pump in the second pumping water pipeline 82 is electrically connected to the first temperature sensor and the second temperature sensor, as well as the control valves in all pumping water branches 821, and the control unit is configured to: when the temperature measured by the second temperature sensor is higher than the temperature measured by the first temperature sensor, and the difference between the two is greater than a preset value, control the variable frequency pump in the second pumping water pipeline 82 to start, and control the control valves in each pumping water branch 821 to open sequentially from top to bottom in an intermittent manner.

[0031] Furthermore, to ensure cleaning effectiveness, a first flow sensor is installed in the first water pump line 81, and a second flow sensor is installed in the second water pump line 82. The control unit of the variable frequency pump in the second water pump line 82 is electrically connected to both the first and second flow sensors. Based on the measured data from the first flow sensor, it automatically adjusts the water flow rate of the second water pump line 82, ensuring that the reading of the second flow sensor matches that of the first flow sensor. This design enables synchronized flow feedback between the lower second nozzle 42, third nozzle 43, and first nozzle 41, thereby guaranteeing cleaning uniformity and effectiveness.

[0032] Furthermore, as a further preferred embodiment, a level sensor is installed inside the circulation tank 2 to monitor the liquid level within the circulation tank 2. The wastewater delivery pipeline 7 controls its flow rate based on the monitoring data from the level sensor to ensure that the liquid level in the circulation tank 2 remains within a preset range. When the frequency of the variable frequency pump in the first pump water pipeline 81 is at its maximum value, and the temperature measured by the first temperature sensor continues to rise (indicating that wastewater concentration has reached its limit), the wastewater delivery pipeline 7 stops delivery and shuts down the evaporation system, transferring all the concentrated wastewater in the circulation tank 2 through the concentrated liquid outlet at its bottom to the CCE system for crystallization-salt extraction.

[0033] As a further preferred embodiment, the outer surface of the coil of the surface evaporator 3 in this embodiment is coated with a Teflon coating to slow down the rate at which crystallized salts in the wastewater adhere to and accumulate on the surface of the coil.

[0034] As a further preferred embodiment, a baffle plate 10 is provided inside the circulation tank 2, located below the inner guide cylinder 6, and coaxially arranged with the inner guide cylinder 6 while maintaining an axial distance. The outer edge of the baffle plate 10 extends radially to the outside of the inner guide cylinder 6. During operation, the baffle plate 10 located at the lower end of the inner guide cylinder 6 can effectively prevent the crystallized salt settled at the bottom conical section of the circulation tank 2 from flowing back into the inner guide cylinder 6 under fluid disturbance, thereby ensuring the purity of the clarified liquid in the inner guide cylinder 6. At the same time, the outer edge of the baffle plate 10 extends beyond the radial range of the inner guide cylinder 6, which can guide the high-concentration salt-containing fluid in the hydraulic vortex motion to continuously settle along the tank wall, avoiding mixing between the high-density area at the bottom and the clear liquid area in the center, thereby maintaining the stability of the liquid entering the inner guide cylinder 6 and improving the separation efficiency of crystallized salt and clear liquid.

[0035] Furthermore, the baffle 10 is circular, and its upper surface is a conical apex. The conical apex design of the baffle 10 effectively prevents the accumulation of crystalline salt at the top of the baffle 10. On the other hand, the conical apex structure can cooperate with the radial flow generated by hydraulic vortex and stirring, allowing the crystalline salt on the outer edge of the baffle 10 to move more smoothly towards the tank wall and fall into the bottom conical section, thereby enhancing the backflow prevention capability against the crystalline salt at the bottom, further ensuring the purity of the clear liquid inside the inner cylinder 6, and improving the long-term stability of the system.

[0036] As a further preferred embodiment, the system also includes a mixer 11; the mixer 11 is fixedly installed on the top of the circulation tank 2, with its stirring shaft located inside the inner guide cylinder 6, and the stirring paddle positioned between the lower end of the inner guide cylinder 6 and the upper end of the baffle plate 10. The cross-sectional area of ​​the rotating envelope of the stirring paddle is larger than the port diameter at the lower end of the inner guide cylinder 6, and it is located inside the outer edge contour of the baffle plate 10. The blades of the stirring paddle have an arc-shaped structure bent around the stirring shaft, with the convex surface of the blades facing its rotation direction, and this rotation direction is consistent with the tangential direction of the guide channel. During operation, when the wastewater is concentrated and a large amount of crystallized salt is precipitated to the point that the hydraulic vortex is insufficient to push it all towards the tank wall, the mixer 11 is activated. Since the rotation direction of the stirring paddle is the same as the direction of the hydraulic vortex, the two work together to enhance the fluid rotation intensity, increase the centrifugal force on the crystallized salt, and ensure that the crystallized salt migrates smoothly to the inner wall; at the same time, the circular baffle plate 10 located below the stirring paddle can effectively prevent the crystallized salt settled at the bottom of the tank from flowing back upward.

[0037] As can be seen from the above, this invention enables the hierarchical coordinated operation of the evaporation system: the first pump water pipeline 81 continuously delivers relatively clear wastewater to the uppermost first nozzle 41, uniformly spraying all surface evaporators and ensuring continuous evaporation operation. Simultaneously, addressing the issue of lower-level evaporators easily adhering to crystalline salts due to their greater distance and weaker rinsing force, the second pump water pipeline 82 can be activated as needed. By sequentially opening the first pump water branch 821-1 and the second pump water branch 821-2, precise and individual rinsing is performed on each lower-level surface evaporator, effectively removing localized crystalline salts and preventing salt accumulation from affecting evaporation efficiency. The entire process requires no shutdown and generates no additional cleaning wastewater. This design balances overall evaporation stability with localized cleaning and maintenance, effectively improving the continuous operation capability and anti-scaling performance of the evaporation system while ensuring cleaning effectiveness.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An online cleaning system for high-salt wastewater based on closed-loop evaporation technology, characterized in that, include: Evaporation tower (1), circulating tank (2), drainage pipeline (9) and pump water pipeline (8), wherein: The evaporator (1) has a circulating air inlet, a circulating air outlet, and a drain outlet; the evaporator (1) has multiple layers of surface evaporators (3) arranged from top to bottom inside, and a corresponding nozzle (4) is arranged above each layer of surface evaporators (3); The circulating tank (2) adopts a circular conical bottom structure and has a concentrated liquid outlet at the bottom; the circumferential wall of the circulating tank (2) is evenly distributed with several guide channels (5) with the same outlet orientation and tangent to the inner wall surface of the tank; the interior of the circulating tank (2) is provided with a vertically arranged inner guide cylinder (6), and the height of the lower end of the inner guide cylinder (6) is not lower than the height of the outlet of the guide channel (5); The inlet end of the drainage pipe (9) is connected to the drain outlet of the evaporator (1), and its outlet end is connected to all the flow channels (5); The water pumping pipeline (8) includes a first water pumping pipeline (81) and a second water pumping pipeline (82); the inlet ends of the first water pumping pipeline (81) and the second water pumping pipeline (82) are respectively connected to the inner cylinder (6) of the drainage. The outlet end of the first water pumping pipeline (81) is connected to all the nozzles (4) located on the uppermost layer. The outlet end of the second water pumping pipeline (82) is provided with multiple water pumping branches (821) that can be independently controlled to open and close. Each water pumping branch (821) corresponds to a layer of nozzles (4) and is connected to all the nozzles (4) of the corresponding layer.

2. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 1, characterized in that, The first pump water pipeline (81) is configured to be normally open; the second pump water pipeline (82) is configured to be intermittently open and closed, and when the second pump water pipeline (82) is open, each pump water branch (821) in the second pump water pipeline (82) is opened sequentially from top to bottom in an intermittent manner.

3. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 2, characterized in that, It also includes a first temperature sensor and a second temperature sensor; wherein, the first temperature sensor is used to monitor the refrigerant temperature at the inlet of the top surface evaporator (3); the second temperature sensor is used to monitor the refrigerant temperature at the inlet of the remaining surface evaporators (3); the first pump water pipeline (81) controls its pump water volume according to the monitoring result of the first temperature sensor; the second pump water pipeline (82) controls its on / off state according to the difference between the temperature measured by the second temperature sensor and the temperature measured by the first temperature sensor.

4. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 3, characterized in that, Both the pumps in the first pumping water pipeline (81) and the second pumping water pipeline (82) are variable frequency pumps; each pumping water branch (821) is controlled by a control valve installed in its pipeline; both the variable frequency pumps in the first pumping water pipeline (81) and the second pumping water pipeline (82) are equipped with control units; wherein, the control unit of the variable frequency pump in the first pumping water pipeline (81) is electrically connected to the first temperature sensor, and the control unit is configured to: when the monitoring data of the first temperature sensor is greater than a preset value, control the first pumping water pipeline (821) (821) to open and close the pumps in the second pumping water pipeline (821). 1) The speed of the variable frequency pump increases; the control unit configured in the variable frequency pump of the second pump water pipeline (82) is electrically connected to the first temperature sensor and the second temperature sensor, as well as the control valves in all pump water branches (821). The control unit is configured to: when the temperature measured by the second temperature sensor is higher than the temperature measured by the first temperature sensor, and the difference between the two is greater than the preset value, control the variable frequency pump in the second pump water pipeline (82) to start, and control the control valves in each pump water branch (821) to open sequentially from top to bottom in an intermittent manner.

5. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 4, characterized in that, The first pumping water pipeline (81) is equipped with a first flow sensor; the second pumping water pipeline (82) is equipped with a second flow sensor; the control unit configured in the variable frequency pump in the second pumping water pipeline (82) is also electrically connected to the first flow sensor and the second flow sensor respectively, and controls the pumping water volume of the second pumping water pipeline (82) according to the data measured by the first flow sensor, so that the data measured by the second flow sensor is consistent with the data measured by the first flow sensor.

6. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 3, characterized in that, It also includes a wastewater delivery pipeline (7) connected to the circulation tank (2) for delivering wastewater to be treated to the circulation tank (2) and a liquid level sensor installed on the circulation tank (2) for monitoring the liquid level in the circulation tank (2); wherein the wastewater delivery pipeline (7) is configured to: control its delivery volume according to the monitoring data of the liquid level sensor so that the liquid level in the circulation tank (2) is maintained within a preset value range; and stop delivery when the frequency of the variable frequency pump in the first pump water pipeline (81) is at its maximum value and the temperature measured by the first temperature sensor continues to rise.

7. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 1, characterized in that, Inside the circulation tank (2) and below the inner cylinder (6), there is a baffle plate (10) that is coaxially arranged with the inner cylinder (6) and maintains an axial distance, and the outer edge of the baffle plate (10) extends radially to the outside of the inner cylinder (6).

8. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 7, characterized in that, The baffle (10) is circular, and its upper surface is a cone top surface.

9. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to claim 7, characterized in that, It also includes a mixer (11); the mixer (11) is fixedly installed on the top of the circulating tank (2), its stirring shaft is located inside the inner cylinder (6), and the stirring paddle is set between the lower end of the inner cylinder (6) and the upper end of the baffle plate (10), and the cross-sectional area of ​​the rotating envelope circle of the stirring paddle is larger than the port diameter of the lower end of the inner cylinder (6), and is located inside the outer edge contour of the baffle plate (10); the blades of the stirring paddle have an arc-shaped structure that is bent around the stirring shaft, the convex surface of the blades faces its rotation direction, and the rotation direction is consistent with the tangential direction of the guide channel.

10. The online cleaning high-salt wastewater evaporation system based on closed-loop evaporation technology according to any one of claims 1-9, characterized in that, The surface of the surface evaporator (3) is coated with a Teflon coating.

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