A high-salinity wastewater treatment process based on low-temperature evaporation

Abstract

This invention belongs to the field of wastewater treatment technology and provides a high-salt wastewater treatment process based on low-temperature evaporation. The process includes the following steps: Step S1: After industrial wastewater passes through a reverse osmosis membrane system, the relatively low-concentration feed solution is further concentrated to produce relatively high-concentration wastewater and pure water. The pure water is recycled at the front end, and the high-salt wastewater is collected in a raw liquid tank; Step S2: The high-salt wastewater in the raw liquid tank is transported to a refrigeration unit for reflux via a raw liquid circulation pump. The refrigeration unit preheats the raw liquid while cooling the circulating water. Compared with the prior art, the beneficial effects of this invention are as follows: By adding the mother liquor into the distillation vessel, the mother liquor, slurry, and salt are moved in different directions by the first and second spiral blades, so that the materials in the distillation vessel can form a continuous circulation movement, allowing the materials to fully exchange heat with the refrigerant and avoiding insufficient heat exchange caused by material accumulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a high-salinity wastewater treatment process based on low-temperature evaporation. BACKGROUND

[0002] After being pretreated by physical and chemical methods (filtration, precipitation, coagulation, oxidation), general industrial wastewater is free of impurities, heavy metals, calcium and magnesium suspensions, organic matter and the like, and a large amount of high-salinity wastewater (such as sodium chloride, sodium sulfate, ammonium chloride, ammonium sulfate and the like) is generated. The conventional end treatment is generally a process of separating brine by RO membrane concentration, multi-effect evaporation, MVR evaporation and the like, recycling and selling the produced industrial salt, and recycling the produced water.

[0003] When the high-salinity wastewater is treated by low-temperature evaporation, the mother liquor needs to be distilled by a distillation kettle. In use, the existing distillation kettle generally drives the mother liquor in the distillation kettle to flow by a spiral blade. However, when the mother liquor gradually reduces to form slurry and salt, the slurry and salt can only move to one end under the driving of the spiral blade, and the slurry and salt cannot flow and circulate in the distillation kettle, so that the slurry and salt are accumulated at one end of the distillation kettle, and the spiral blade needs to be frequently reversed. However, the spiral blade needs time to reverse, and the accumulated material also needs time to be scattered, and the slurry and salt are accumulated every time the spiral blade rotates, so that the heat exchange between the slurry and the refrigerant is uneven, and the distillation efficiency is reduced. SUMMARY

[0004] The application aims to provide a high-salinity wastewater treatment process based on low-temperature evaporation, and aims to solve the technical problem of uneven heat exchange caused by material accumulation in the prior art, and reduce the distillation efficiency.

[0005] The application is implemented as follows. A high-salinity wastewater treatment process based on low-temperature evaporation includes the following steps.

[0006] Step S1: After the industrial wastewater passes through a reverse osmosis membrane system, the relatively low-concentration mother liquor is further concentrated to produce relatively high-concentration wastewater and pure water. The pure water is recycled to the front end, and the high-salinity wastewater is collected in a raw liquid tank.

[0007] Step S2: The high-salinity wastewater in the raw liquid tank is delivered to a refrigeration unit by a raw liquid circulating pump to flow back. The refrigeration unit preheats the raw liquid while refrigerating the circulating water.

[0008] Step S3: When the raw liquid in the raw liquid tank is preheated to a set temperature, a first water production pump is started. The condensate water in the first water production tank is delivered to a vacuum device to circulate. A vacuum valve is opened, and the first separator gradually approaches a vacuum state. A raw liquid inlet valve is opened, and the raw liquid in the raw liquid tank enters the first separator. When the liquid level in the first separator reaches a set height, a circulating pump is started, and the raw liquid circulates through the first heat exchanger.

[0009] Step S4: Start the compressor in the heat pump system, the low-temperature and low-pressure gaseous refrigerant is compressed and sucked, and then compressed, and enters the first heat exchanger to heat the waste water, and the liquid in the first separator continues to evaporate at a set temperature after receiving heat, while the gaseous refrigerant is condensed into liquid in the first heat exchanger, and then enters the second heat exchanger after temperature and pressure reduction by an expansion valve;

[0010] Step S5: The secondary steam generated by evaporation in the first separator is eliminated by the top wire mesh demister, and then enters the second heat exchanger to provide heat for the liquid refrigerant, and the liquid refrigerant evaporates after receiving heat to return to the low-temperature and low-pressure gaseous refrigerant to the compressor, while the secondary steam is condensed into water and is pumped to the first water tank by the vacuum equipment, and the liquid level in the first water tank reaches a set height and is discharged through the water discharge valve;

[0011] Step S6: The salt concentration of the liquid in the first separator is continuously concentrated, and the crystalline salt is separated out when the concentration reaches the saturation concentration and continues to evaporate, and the crystalline salt is separated out and packed for external transportation after reaching the set solid content, and the enriched mother liquor is discharged to the mother liquor tank and is pumped into the distillation kettle by the mother liquor pump;

[0012] Step S7: The condensed water in the second water tank is pumped to the vacuum equipment by the second water delivery to circulate, the vacuum degree in the distillation kettle rises, the electric heating in the heating tank is started, and the water in the heating tank generates steam and is sucked by the vacuum equipment, and the steam is preheated to a set temperature by heat exchange with the refrigerant through the third heat exchanger;

[0013] Step S8: Start the compressor, the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant, and enters the jacket outside the distillation kettle through the oil separation, while the liquid in the distillation kettle is stirred, the refrigerant and the liquid are fully heat exchanged, the gaseous refrigerant is condensed into liquid in the jacket, and then enters the third heat exchanger after temperature and pressure reduction by an expansion valve;

[0014] Step S9: The secondary steam generated by evaporation in the distillation kettle is eliminated by the top wire mesh demister of the second separator, and then enters the third heat exchanger to provide heat for the liquid refrigerant, and the liquid refrigerant evaporates after receiving heat to return to the low-temperature and low-pressure gaseous refrigerant to the compressor, while the secondary steam is condensed into water and is pumped to the second water tank by the vacuum equipment, and the liquid level in the second water tank reaches a set height and is discharged through the water discharge valve;

[0015] Step S10: The enriched mother liquor in the distillation kettle continuously evaporates, and the salt in the liquid is separated out first into slurry, and then further dried to form dry salt, and then the dry salt in the distillation kettle is discharged and collected;

[0016] The distillation kettle is provided with a jacket outside, one side of the distillation kettle is provided with a material dropping groove and a closing plate is arranged in the material dropping groove, a stirring shaft driven by a first rotating power element is rotatably arranged in the distillation kettle, a first spiral blade is fixedly arranged on the stirring shaft, the first spiral blade, the stirring shaft and the inner wall of the distillation kettle are all provided with a gap, mounting rings are rotatably arranged at both ends of the stirring shaft, supports are fixedly arranged on the mounting rings, a second spiral blade is fixedly arranged on two groups of supports, the second spiral blade is in sliding contact with the outside of the first spiral blade, the second spiral blade and the inner wall of the distillation kettle are provided with a gap, the second spiral blade and the first spiral blade form a complete spiral structure when being located at a set position, and a power assembly for driving the mounting rings to rotate is arranged on the distillation kettle.

[0017] Further technical solutions: the power assembly comprises a second rotating power element, the second rotating power element is fixedly arranged on the side wall of the distillation kettle, the output shaft of the second rotating power element extends into the distillation kettle and is parallel to the stirring shaft, a gear is fixedly arranged at the end of the output shaft of the second rotating power element, the gear is engaged with a gear ring fixedly arranged on the mounting ring, and the gear ring is coaxially arranged with the mounting ring.

[0018] Further technical solutions: a rotating ring is fixedly arranged on the support, the rotating ring is coaxially arranged with the stirring shaft, a plurality of uniformly distributed scrapers are fixedly arranged on the rotating ring, and the scrapers are in sliding contact with the inner wall of the distillation kettle.

[0019] Further technical solutions: the rotating track of the scraper covers the area from the end of the second spiral blade to the end of the distillation kettle.

[0020] Further technical solutions: a guide plate is fixedly arranged on the surface of the front side of the rotating direction of the scraper, the guide plate is arranged at an angle with the side wall of the distillation kettle, the guide plate is in sliding contact with the inner wall of the distillation kettle, and the opening of the guide plate and the inner wall of the distillation kettle faces away from the end of the distillation kettle.

[0021] Further technical solutions: a first telescopic element is fixedly arranged at the end of the distillation kettle, and the output end of the first telescopic element is fixedly connected with the closing plate.

[0022] Further technical solutions: a clamping groove is arranged on the side of the closing plate in the distillation kettle, an arc-shaped cleaning plate is slidingly arranged in the clamping groove, and a second telescopic element for driving the cleaning plate to move is fixedly arranged on the closing plate.

[0023] Further technical solutions: a connecting rod is fixedly arranged at the output end of the second telescopic element, the connecting rod is parallel to the second telescopic element, the connecting rod is slidingly connected with the closing plate and fixedly connected with the cleaning plate, the connecting rod is arranged at an angle with the stirring shaft, and when the cleaning plate moves away from the closing plate, the distance between the cleaning plate and the side wall of the bottom of the distillation kettle decreases.

[0024] Compared with the prior art, the beneficial effects of the present application are as follows:

[0025] 1、The mother liquor is added into the distillation kettle, and the mother liquor, slurry and salt are pushed in different directions by the first spiral blade and the second spiral blade, so that the materials in the distillation kettle can form uninterrupted circulating movement, so that the materials can be fully heat exchanged with the refrigerant, avoiding insufficient heat exchange caused by material accumulation, and improving the distillation efficiency of the materials.

[0026] 2、When the second spiral blade rotates, it drives the multiple scrapers to rotate synchronously through the rotating ring. The scrapers drive the slurry and salt to move upwards in the upward rotating process from the bottom of the distillation kettle. When the scrapers rotate to the downward inclined process, the slurry and salt on the scrapers will descend along the scrapers under the action of gravity, and will fall away from the end of the distillation kettle under the action of the guide plate, so that the materials located at the end of the distillation kettle can be moved to the coverage area of the first spiral blade and the second spiral blade again. The subsequent first spiral blade and the second spiral blade can continue to push the materials to participate in the circulating movement, avoiding the accumulation of materials at the end of the distillation kettle which cannot participate in the material circulation, further improving the uniformity of the heat exchange between the materials and the refrigerant, and improving the distillation effect.

[0027] 3、When a large amount of dry salt in the distillation kettle leaves the distillation kettle, part of the dry salt will be left in the position which cannot be covered by the first spiral blade and the second spiral blade at the end of the distillation kettle. At this time, the first telescopic part first drives the closing plate to reset, and then the second telescopic part is retracted and drives the cleaning plate to move through the connecting rod. When the cleaning plate moves away from the closing plate, it will gradually approach the bottom of the distillation kettle. When the cleaning plate contacts the bottom of the distillation kettle, it stops moving. At this time, the first telescopic part drives the closing plate to move away from the distillation kettle again, and the cleaning plate moves synchronously. The dry salt left at the end of the distillation kettle is scraped out by the cleaning plate, so that the dry salt can completely leave the distillation kettle, avoiding the influence of the residual dry salt in the distillation kettle on the subsequent use. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flow chart of the salt separation system in the present application.

[0029] Figure 2 The flow chart of the mother liquor treatment system in the present application.

[0030] Figure 3 The structure diagram of the distillation kettle in the present application.

[0031] Figure 4 The sectional structure diagram of the distillation kettle in the present application.

[0032] Figure 5 The structure diagram of the first stirring blade and the second stirring blade in the present application.

[0033] Figure 6 The Figure 4A magnified view of region A1 in the middle.

[0034] Figure 7 for Figure 4 A magnified view of region A2 in the middle.

[0035] In the attached diagram: 1. Raw material tank; 2. Raw material circulation pump; 3. Refrigeration unit; 4. First product water pump; 5. First product water tank; 6. First separator; 7. Circulation pump; 8. First heat exchanger; 9. Second heat exchanger; 10. Brine discharge pump; 11. Mother liquor tank; 12. Distillation kettle; 13. Second separator; 14. Second product water tank; 15. Second product water pump; 16. Heating tank; 17. Third heat exchanger; 18. Stirring shaft; 19. First spiral blade; 20. First rotating power component; 21. Mounting ring; 22. Gear ring; 23. Gear; 24. Second rotating power component; 25. Support; 26. Second spiral blade; 27. Rotating ring; 28. Scraper; 29. ​​Guide plate; 30. Sealing plate; 31. First telescopic component; 32. Second telescopic component; 33. Connecting rod; 34. Cleaning plate; 35. Slot; 36. Power assembly. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0038] like Figures 1-7 As shown, this invention provides a high-salinity wastewater treatment process based on low-temperature evaporation, the process comprising the following steps:

[0039] Step S1: After passing through the reverse osmosis membrane system, the relatively low-concentration feed solution of industrial wastewater is further concentrated to produce relatively high-concentration wastewater and pure water. The pure water is reused at the front end, and the high-salt wastewater is collected in the raw liquid tank 1.

[0040] Step S2: The high-salt wastewater in the raw liquid tank 1 is transported to the refrigeration unit 3 for refrigeration via the raw liquid circulation pump 2. The refrigeration unit 3 preheats the raw liquid while cooling the circulating water.

[0041] Step S3: When the raw liquid in the raw liquid tank 1 is preheated to the set temperature, start the first water production pump 4. The condensate in the first water production tank 5 is circulated through the vacuum equipment by the first water production pump 4. Open the vacuum valve and the first separator 6 gradually approaches the vacuum state. Open the raw liquid feed valve and the liquid in the raw liquid tank 1 enters the first separator 6. After the liquid level in the first separator 6 reaches the set height, start the circulation pump 7 and the liquid is circulated through the first heat exchanger 8.

[0042] Step S4: Start the compressor in the heat pump system. The low-temperature and low-pressure gaseous refrigerant is compressed and drawn in. After being compressed, it passes through the oil separator to the first heat exchanger 8 to heat the wastewater. The liquid that has received heat returns to the first separator 6 and continues to evaporate at the set temperature. At the same time, the gaseous refrigerant condenses into liquid in the first heat exchanger 8. After being de-cooled and de-pressurized by the expansion valve, it enters the second heat exchanger 9.

[0043] Step S5: The secondary steam generated by evaporation in the first separator 6 is eliminated by the top wire mesh demister to remove gas phase entrainment, and then enters the second heat exchanger 9 to provide heat to the liquid refrigerant. After receiving heat, the liquid refrigerant evaporates and turns back into low-temperature, low-pressure gaseous refrigerant, which returns to the compressor. At the same time, the secondary steam condenses into water and is drawn into the first water production tank 5 by the vacuum equipment. After the liquid level in the first water production tank 5 reaches the set height, it is discharged through the water production drain valve.

[0044] Step S6: The salt concentration of the liquid in the first separator 6 is continuously concentrated until it reaches saturation. After continuous evaporation, crystallized salt begins to precipitate. Once the set solid content is reached, the salt is pumped into a centrifuge by the salt discharge pump 10 to separate the salt. The crystallized salt is packaged and transported out. The enriched mother liquor is discharged into the mother liquor tank 11 and pumped into the distillation kettle 12 for processing by the mother liquor pump.

[0045] Step S7: The condensate in the second water production tank 14 is circulated through the vacuum equipment via the second water production pump 15. The vacuum in the distillation kettle 12 increases, and the electric heating in the heating tank 16 is started. The water in the heating tank 16 generates steam and is attracted by the vacuum equipment. It exchanges heat with the refrigerant through the third heat exchanger 17 and preheats the refrigerant to the set temperature.

[0046] Step S8: Start the compressor. The low-temperature and low-pressure gaseous refrigerant is compressed into a high-temperature and high-pressure gaseous refrigerant. It enters the jacket outside the distillation vessel 12 through the oil separator. At the same time, the liquid in the distillation vessel 12 is stirred. The refrigerant and the liquid exchange heat fully. The gaseous refrigerant condenses into a liquid in the jacket. After being depressurized by the expansion valve, it enters the third heat exchanger 17.

[0047] Step S9: The secondary steam generated by evaporation in the distillation kettle 12 passes through the wire mesh demister at the top of the second separator 13 to eliminate gas phase entrainment, and then enters the third heat exchanger 17 to provide heat to the liquid refrigerant. After receiving heat, the liquid refrigerant evaporates and returns to the low-temperature, low-pressure gaseous refrigerant and returns to the compressor. At the same time, the secondary steam condenses into water and is drawn into the second water production tank 14 by the vacuum equipment. After the liquid level in the second water production tank 14 reaches the set height, it is discharged through the water production drain valve.

[0048] Step S10: The enriched mother liquor in the distillation kettle 12 is continuously evaporated, and the salt in the liquid is continuously precipitated out first to become a slurry, and then further dried to form dry salt. After that, the dry salt in the distillation kettle 12 is discharged and collected.

[0049] The distillation vessel 12 is provided with a jacket on its outer side. A material discharge trough is provided on one side of the distillation vessel 12, and a sealing plate 30 is provided inside the material discharge trough. A stirring shaft 18 driven by a first rotating power component 20 is rotatably installed inside the distillation vessel 12. A first spiral blade 19 is fixedly installed on the stirring shaft 18. The first spiral blade 19 is spaced from the stirring shaft 18 and the inner wall of the distillation vessel 12. Mounting rings 21 are rotatably installed at both ends of the stirring shaft 18. A bracket 25 is fixedly installed on the mounting ring 21. A second spiral blade 26 is fixedly installed on both sets of brackets 25. The second spiral blade 26 slides in contact with the outer side of the first spiral blade 19. A gap is provided between the second spiral blade 26 and the inner wall of the distillation vessel 12. When the second spiral blade 26 and the first spiral blade 19 are in a set position, they form a complete spiral structure. A power component 36 is provided on the distillation vessel 12 to drive the mounting rings 21 to rotate.

[0050] In practical application, when the mother liquor enters the distillation vessel 12, the first rotating power component 20 drives the stirring shaft 18 to rotate, which in turn drives the first spiral blade 19 to rotate. The power assembly 36 drives the mounting ring 21 to rotate, which in turn drives the second spiral blade 26 to rotate. The first spiral blade 19 and the second spiral blade 26 rotate in opposite directions. When the second spiral blade 26 rotates, it pushes the mother liquor towards the direction of the sealing plate 30. When there is a large amount of mother liquor in the distillation vessel 12, the first spiral blade 19 and the second spiral blade 26 drive the mother liquor to circulate, so that the mother liquor can fully exchange heat with the refrigerant in the jacket. As the mother liquor in the distillation vessel 12 continues to evaporate, the salt in the mother liquor continuously precipitates out, first becoming a slurry, and then further dried to form dry salt. Both the slurry and the dry salt will exist at the bottom of the distillation vessel 12. When there is slurry and salt in the distillation vessel 12, the second spiral blade 26 pushes some of the slurry and salt at the bottom to move, and the first spiral blade 19 pushes the slurry and salt at the top to move. The first spiral blade 19 and the second spiral blade 26 push the slurry and salt... The opposing directions of movement allow the slurry and salt to circulate repeatedly within the distillation vessel 12, ensuring that the slurry and moist salt can fully exchange heat with the refrigerant. Eventually, only dry salt remains in the distillation vessel 12. The first spiral blade 19 and the second spiral blade 26 push the mother liquor, slurry, and salt in different directions, enabling the materials in the distillation vessel 12 to form a continuous circulation. This ensures that the materials can fully exchange heat with the refrigerant, avoiding insufficient heat exchange due to material accumulation and improving the distillation efficiency. When only dry salt remains in the distillation vessel 12, the sealing plate 30 is opened, and the stirring shaft 18 stops rotating when it reaches its initial position. When the second spiral blade 26 reaches its initial position, the stirring shaft 18 rotates in the opposite direction at the same speed as the second spiral blade 26. At this time, the first spiral blade 19 and the second spiral blade 26 form a complete spiral structure. The first spiral blade 19 and the second spiral blade 26 together push the dry salt in the distillation vessel 12 toward the discharge chute and leave the distillation vessel 12 through the discharge chute.

[0051] The refrigeration unit 3 preheats the raw liquid while producing cooling water, which is more energy-efficient than the waste caused by dissipating heat through air cooling. The high condensing temperature refrigerant needs to be preheated before starting. The water is heated by electric heating and vaporized under the vacuum generated by the vacuum equipment. It is then drawn to the second heat exchanger 9 to preheat the refrigerant. It takes advantage of the high enthalpy of steam, which is more efficient than traditional hot water preheating and saves the hot water circulation pump.

[0052] In one example of this embodiment, the first rotating power component 20 is a first motor, but it can also be a hydraulic motor or other components capable of outputting rotational power. The first motor drives the first spiral blade 19 to rotate. The secondary steam outlets of the first separator 6 and the second separator 13 are both connected in parallel to a secondary steam condenser. The high-pressure balance regulating valve balances the extra heat generated by the compressor to avoid excessively high pressure. The hot gas bypass pipeline prevents excessively low pressure. The secondary steam condenser not only balances the extra heat generated by the compressor, but also increases the water production. Compared with traditional refrigeration systems that dissipate heat through air cooling or plate heat exchangers, it is more energy-efficient and improves processing efficiency.

[0053] like Figure 4 , Figure 6 As shown, this invention provides a high-salt wastewater treatment process based on low-temperature evaporation. The power component 36 includes a second rotating power component 24, which is fixedly installed on the side wall of the distillation vessel 12. The output shaft of the second rotating power component 24 extends into the distillation vessel 12 and is parallel to the stirring shaft 18. A gear 23 is fixedly installed at the end of the output shaft of the second rotating power component 24. The gear 23 meshes with a gear ring 22 fixedly installed on the mounting ring 21. The gear ring 22 and the mounting ring 21 are coaxially arranged.

[0054] In practical application, the second rotating power component 24 drives the mounting ring 21 to rotate through the meshing gear 23 and gear ring 22, and then the mounting ring 21 drives the second spiral blade 26 to rotate through the bracket 25.

[0055] In one embodiment of the present invention, the second rotating power component 24 is a second motor, or it can be a hydraulic motor or other component capable of outputting rotational power, which drives the second spiral blade 26 to rotate.

[0056] like Figure 4 , Figure 5 As shown, this invention provides a high-salt wastewater treatment process based on low-temperature evaporation. A rotating ring 27 is fixedly installed on the support 25. The rotating ring 27 is coaxially arranged with the stirring shaft 18. Multiple sets of evenly distributed scrapers 28 are fixedly installed on the rotating ring 27. The scrapers 28 slide in contact with the inner wall of the distillation vessel 12.

[0057] Specifically, the rotational trajectory of the scraper 28 covers the area from the end of the second helical blade 26 to the end of the distillation vessel 12.

[0058] Specifically, a guide plate 29 is fixedly installed on the surface of the scraper 28 in the direction of rotation. The guide plate 29 is at an angle to the side wall of the distillation vessel 12. The guide plate 29 slides in contact with the inner wall of the distillation vessel 12. The openings of the guide plate 29 and the inner wall of the distillation vessel 12 face away from the end of the distillation vessel 12.

[0059] In practical application, when the second spiral blade 26 rotates, it drives the multiple scrapers 28 to rotate synchronously via the rotating ring 27. As the scrapers 28 rotate upward from the bottom of the distillation vessel 12, they move the slurry and salt upward. When the scrapers 28 rotate downward, the slurry and salt on them will descend along the scrapers 28 under the action of gravity and fall away from the end of the distillation vessel 12 under the action of the guide plate 29. This allows the material at the end of the distillation vessel 12 to move back to the coverage area of ​​the first spiral blade 19 and the second spiral blade 26. Subsequently, the first spiral blade 19 and the second spiral blade 26 can continue to push the material to participate in the circulation movement, avoiding the accumulation of material at the end of the distillation vessel 12 that cannot participate in the material circulation, further improving the uniformity of heat exchange between the material and the refrigerant, and improving the distillation effect.

[0060] like Figure 3 , Figure 4 , Figure 7 As shown, this invention provides a high-salt wastewater treatment process based on low-temperature evaporation. A first telescopic component 31 is fixedly installed at the end of the distillation vessel 12, and the output end of the first telescopic component 31 is fixedly connected to the sealing plate 30.

[0061] Specifically, the sealing plate 30 has a slot 35 on its side inside the distillation vessel 12. An arc-shaped cleaning plate 34 is slidably installed in the slot 35. A second telescopic component 32 that drives the cleaning plate 34 to move is fixedly installed on the sealing plate 30.

[0062] Specifically, a connecting rod 33 is fixedly installed at the output end of the second telescopic member 32. The connecting rod 33 is parallel to the second telescopic member 32. The connecting rod 33 is slidably connected to the sealing plate 30 and fixedly connected to the cleaning plate 34. The connecting rod 33 is set at an angle with the stirring shaft 18. When the cleaning plate 34 moves away from the sealing plate 30, its distance from the bottom side wall of the distillation vessel 12 decreases.

[0063] In practical application, when only dry salt remains in the distillation vessel 12, the first telescopic member 31 extends, causing the sealing plate 30 to move away from the distillation vessel 12, thus opening the discharge chute. At this time, the dry salt in the distillation vessel 12 can leave through the discharge chute. After a large amount of dry salt leaves the distillation vessel 12, some dry salt will remain in the area not covered by the first spiral blade 19 and the second spiral blade 26 at the end of the distillation vessel 12. At this time, the first telescopic member 31 first drives the sealing plate 30 to reset, and then the second telescopic member 32 retracts and drives the cleaning plate 34 to move through the connecting rod 33. As the cleaning plate 34 moves away from the sealing plate 30, it gradually approaches the bottom of the distillation vessel 12. When the cleaning plate 34 contacts the bottom of the distillation vessel 12, it stops moving. At this time, the first telescopic member 31 again drives the sealing plate 30 to move away from the distillation vessel 12, and the cleaning plate 34 moves synchronously. The cleaning plate 34 scrapes out the dry salt remaining at the end of the distillation vessel 12, so that the dry salt can completely leave the distillation vessel 12, avoiding the dry salt remaining in the distillation vessel 12 from affecting subsequent use.

[0064] In one embodiment of the present invention, the first telescopic member 31 and the second telescopic member 32 are respectively the first electric telescopic rod and the second electric telescopic rod. Of course, they can also be other components that can actively change length, such as hydraulic cylinders. The first electric telescopic rod drives the closing plate 30 to move, and the second electric telescopic rod drives the cleaning plate 34 to move.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0066] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for treatment of high salinity wastewater based on low temperature evaporation, characterized in that, The process comprises the following steps: Step S1: After the industrial wastewater passes through the reverse osmosis membrane system, the relatively low concentration of feed liquid is further concentrated, and relatively high concentration of wastewater and pure water are produced, the pure water is used in the front end, and the high-salt wastewater is collected into the raw liquid tank (1); Step S2: The high-salt wastewater in the raw liquid tank (1) is transported to the refrigeration unit (3) by the raw liquid circulating pump (2) to return flow, and the refrigeration unit (3) preheats the raw liquid while refrigerating the circulating water; Step S3: When the raw liquid in the raw liquid tank (1) is preheated to the set temperature, start the first water production pump (4), the condensed water in the first water production tank (5) is circulated by the first water production pump (4) through the vacuum equipment, the vacuum valve is opened, the first separator (6) gradually approaches the vacuum state, the raw liquid inlet valve is opened, and the raw liquid tank (1) The feed liquid enters the first separator (6), and when the liquid level in the first separator (6) reaches the set height, start the circulating pump (7), and the feed liquid is circulated through the first heat exchanger (8); Step S4: Start the compressor in the heat pump system, and the low-temperature and low-pressure gaseous refrigerant is compressed after being sucked into the compressor, and is sent to the first heat exchanger (8) through the oil separation to heat the wastewater, and the feed liquid receiving heat returns to the first separator (6) to continue evaporation at the set temperature, while the gaseous refrigerant is condensed into liquid in the first heat exchanger (8), and after being reduced in temperature and pressure through the expansion valve, it enters the second heat exchanger (9); Step S5: The secondary steam generated by evaporation in the first separator (6) is removed by the top wire mesh demister to eliminate gas entrainment, and then enters the second heat exchanger (9) to provide heat to the liquid refrigerant, and the liquid refrigerant evaporates after receiving heat to become low-temperature and low-pressure gaseous refrigerant back to the compressor, while the secondary steam condenses into water and is pumped to the first water production tank (5) by the vacuum equipment, and when the liquid level in the first water production tank (5) reaches the set height, it is discharged through the water production discharge valve; Step S6: The salt concentration of the feed liquid in the first separator (6) is continuously concentrated, reaches the saturated concentration and continues to evaporate, and then begins to precipitate crystalline salt, reaches the set solid content, and is separated by the centrifuge through the salt discharge pump (10), the crystalline salt is packaged and shipped, and the enriched mother liquor is discharged into the mother liquor tank (11) and is treated by the mother liquor pump into the distillation kettle (12); Step S7: The condensed water in the second water production tank (14) is circulated by the second water production pump (15) through the vacuum equipment, the vacuum degree in the distillation kettle (12) rises, the electric heating in the heating tank (16) is started, the water in the heating tank (16) generates steam and is sucked by the vacuum equipment, and the steam exchanges heat with the refrigerant through the third heat exchanger (17) to preheat the refrigerant to the set temperature; Step S8: Start the compressor, and the low-temperature and low-pressure gaseous refrigerant is compressed into high-temperature and high-pressure gaseous refrigerant, which enters the jacket outside the distillation kettle (12) through the oil separation, and at the same time, the feed liquid in the distillation kettle (12) is stirred, and the refrigerant and the feed liquid are fully heat exchanged, and the gaseous refrigerant is condensed into liquid in the jacket, and after being reduced in temperature and pressure through the expansion valve, it enters the third heat exchanger (17); Step S9: The secondary steam generated by evaporation in the distillation kettle (12) passes through the top wire mesh demister of the second separator (13) to eliminate the gas phase entrainment, and then enters the third heat exchanger (17) to provide heat for the liquid coolant, and the liquid coolant is evaporated after receiving heat to become low-temperature and low-pressure gaseous coolant back to the compressor, while the secondary steam is condensed into water and is pumped to the second water tank (14) by the vacuum device, and when the liquid level in the second water tank (14) reaches the set height, it is discharged through the water discharge valve; Step S10: The enriched mother liquor in the distillation kettle (12) is continuously evaporated, and the salt in the liquid is continuously precipitated to become slurry, and then is further dried to form dry salt, and then the dry salt in the distillation kettle (12) is discharged and collected; The distillation kettle (12) is provided with a jacket on the outside, one side of the distillation kettle (12) is provided with a feeding chute, and a closing plate (30) is arranged in the feeding chute, a stirring shaft (18) driven by a first rotary power element (20) is rotatably installed in the distillation kettle (12), a first spiral blade (19) is fixedly installed on the stirring shaft (18), the first spiral blade (19), the stirring shaft (18) and the inner wall of the distillation kettle (12) are all provided with a gap, mounting rings (21) are rotatably installed at both ends of the stirring shaft (18), supports (25) are fixedly installed on the mounting rings (21), a second spiral blade (26) is fixedly installed on the two groups of supports (25), the second spiral blade (26) is in sliding contact with the outside of the first spiral blade (19), and the second spiral blade (26) and the inner wall of the distillation kettle (12) are provided with a gap, when the second spiral blade (26) and the first spiral blade (19) are located at a set position, a complete spiral structure is formed, and a power assembly (36) for driving the mounting ring (21) to rotate is arranged on the distillation kettle (12). The power assembly (36) comprises a second rotary power element (24), the second rotary power element (24) is fixedly installed on the side wall of the distillation kettle (12), the output shaft of the second rotary power element (24) extends into the distillation kettle (12) and is parallel to the stirring shaft (18), a gear (23) is fixedly installed at the output shaft of the second rotary power element (24), the gear (23) is engaged with a gear ring (22) fixedly installed on the mounting ring (21), and the gear ring (22) is coaxially arranged on the mounting ring (21).

2. A high salinity wastewater treatment process based on low temperature evaporation as claimed in claim 1, wherein, A rotating ring (27) is fixedly installed on the support (25), the rotating ring (27) is coaxially arranged on the stirring shaft (18), a plurality of uniformly distributed scrapers (28) are fixedly installed on the rotating ring (27), and the scrapers (28) are in sliding contact with the inner wall of the distillation kettle (12).

3. A high salinity wastewater treatment process based on low temperature evaporation according to claim 2, characterized in that, The rotating track of the scraper (28) covers the area from the end of the second spiral blade (26) to the end of the distillation kettle (12).

4. A low temperature evaporation based high salinity wastewater treatment process as claimed in claim 2, wherein, A guide plate (29) is fixedly installed on the surface of the front side of the rotating direction of the scraper (28), the guide plate (29) is arranged at an angle with the side wall of the distillation kettle (12), the guide plate (29) is in sliding contact with the inner wall of the distillation kettle (12), and the opening of the guide plate (29) and the inner wall of the distillation kettle (12) faces away from the end of the distillation kettle (12).

5. A low temperature evaporation based high salinity wastewater treatment process as claimed in claim 1, wherein, The first telescopic part (31) is fixedly installed at the end of the distillation kettle (12), and the output end of the first telescopic part (31) is fixedly connected with the closing plate (30).

6. A low-temperature evaporation-based high-salinity wastewater treatment process according to claim 5, characterized in that, The closing plate (30) is provided with a clamping groove (35) on the side surface in the distillation kettle (12), the clamping groove (35) is slidably provided with an arc-shaped cleaning plate (34), and the closing plate (30) is fixedly provided with a second telescopic part (32) for driving the cleaning plate (34) to move.

7. A low-temperature evaporation-based high-salinity wastewater treatment process according to claim 6, characterized in that, The output end of the second telescopic part (32) is fixedly provided with a connecting rod (33), the connecting rod (33) is parallel to the second telescopic part (32), the connecting rod (33) is slidably connected with the closing plate (30) and fixedly connected with the cleaning plate (34), the connecting rod (33) and the stirring shaft (18) are provided with an included angle, and when the cleaning plate (34) moves away from the closing plate (30), the distance between the cleaning plate (34) and the bottom side wall of the distillation kettle (12) is reduced.

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