Low-energy-consumption separation system for recovering sodium chloride and sodium sulfate

Abstract

The low-energy-consumption separation system comprises a dissolving tank, a first centrifugal machine, a heat exchanger, a temperature reduction evaporation device, a second centrifugal machine, a condensate water tank and a vacuum pump, an oxidizing agent feeding opening and a mixed salt liquid feeding opening are formed in the dissolving tank, and an oxidizing agent can eliminate organic matter in mixed salt; sodium sulfate solids are separated out from liquid in the dissolving tank in a supersaturated state, solid sodium sulfate in mixed liquid discharged from the dissolving tank is separated out through a first centrifugal machine, mother liquor discharged from the first centrifugal machine is fed into a heat exchanger to be subjected to heat exchange with condensate water for cooling, and the cooled mother liquor is subjected to negative-pressure low-temperature evaporation in a temperature reduction evaporation device; after sodium chloride is separated out, the sodium chloride and the tail liquid are separated through the second centrifugal machine, the tail liquid is fed into the dissolving tank for retreatment, and condensate water heated through heat exchange is reused for the dissolving tank, so that the separation system is simple and reasonable in structure, heat recycling of mother liquor is achieved through the heat exchanger, and low-energy-consumption and low-cost resource recycling is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of industrial wastewater treatment, and in particular to a separation system for realizing resource recovery during industrial wastewater treatment, and specifically to a low-energy separation system for recovering sodium chloride and sodium sulfate in industrial wastewater. Background Art

[0002] High-concentration salt solutions contain large amounts of soluble salts, organic matter, and metal ions, which interact with various inorganic compounds in wastewater, resulting in complex physical and chemical properties. Based on the production goals of environmental protection and resource recovery, extracting recyclable industrial salt from high-concentration salt solutions that can be put into production has become an industry consensus.

[0003] In industrial high-salt wastewater treatment projects, such as zero wastewater discharge and integrated desulfurization ash disposal, if the by-product crystalline salt is disposed of in the form of mixed salt, there are problems with low resource utilization and high disposal costs. In addition, sodium sulfate and sodium chloride are the main by-product salts and can be recycled as industrial raw materials to reduce treatment costs. Therefore, how to effectively, economically, and efficiently recover sodium chloride and sodium sulfate from high-salt industrial wastewater to achieve resource utilization of crystalline salt has become an urgent problem to be solved in the industry.

[0004] Chinese invention patent CN118026215A discloses a method for separating salt from a solution containing sodium chloride and sodium sulfate. The method comprises dissolving the mixed salt first, separating and drying the undissolved sodium sulfate to obtain anhydrous sodium sulfate, and then freezing and crystallizing the mixed salt to obtain sodium sulfate. The sodium sulfate is then returned to the solution and dissolved again, and the mother liquor of the frozen crystallization is evaporated and crystallized at high temperature to obtain sodium chloride solid.

[0005] Although the salt-dividing method disclosed in the above patent document has been improved in the freezing crystallization and evaporation crystallization routes, it still has great defects: first, there are generally organic impurities in the mixed crystallized salt, and the method disclosed in the patent document does not have a corresponding treatment process. If the mother liquor has been circulating in the system, the organic matter will eventually precipitate out along with the crystallized salt, affecting the purity and whiteness of the crystallized salt; secondly, cooling crystallization needs to reduce the salting-out mother liquor to about 0 ° C, and evaporation crystallization is then heated from 0 ° C to about 100 ° C, requiring high energy consumption, and the salt-distilled by cooling crystallization needs to be dissolved at high temperature again, and the process is repeated and increases energy consumption. Therefore, although the salt-dividing method disclosed in the above patent document can realize sodium chloride resource recovery, it still has the problem that the purity of sodium chloride is not high and the energy consumption required for treatment is large, resulting in high processing cost.

[0006] Therefore, there are still many defects in the current recycling of industrial salt resources, and it is urgent to propose a new technical solution to solve the problems existing in the existing technology. Utility Model Content

[0007] The present application provides a low-energy separation system for recovering sodium chloride and sodium sulfate, so as to solve the problem of high processing costs caused by high energy consumption in traditional salt separation systems.

[0008] In order to achieve the above objectives, this application provides the following technical solutions:

[0009] The present application provides a low-energy separation system for recovering sodium chloride and sodium sulfate, comprising a dissolving tank, a first centrifuge, a heat exchanger, a cooling evaporation device, a second centrifuge, a condensed water tank, and a vacuum pump, wherein:

[0010] The dissolving tank comprises a tank body and a heat-insulating jacket arranged outside the tank body, wherein the tank body is provided with an oxidant feeding port, a mixed salt liquid feeding port, a tail liquid return port, a water inlet and a discharge port;

[0011] The first centrifuge has a feed inlet, a sodium sulfate discharge outlet and a mother liquor discharge outlet, and the feed inlet is connected to the discharge outlet of the dissolving tank;

[0012] The heat exchanger has a heat exchange medium inlet, a heat exchange medium outlet, a water injection port and a water supply port, the mother liquid discharge port is connected to the heat exchange medium inlet, the heat exchange medium outlet is connected to the mother liquid inlet of the temperature reduction evaporation device, the water injection port is connected to the condensed water tank, and the water supply port is connected to the water inlet;

[0013] The discharge port of the desuperheating evaporation device is connected to the liquid inlet of the second centrifuge, and the tail liquid discharge port of the second centrifuge is connected to the tail liquid return port.

[0014] Furthermore, in the above technical solution, the insulation jacket is provided with a steam inlet and a condensed water outlet, and the insulation jacket is used to continuously keep the liquid in the dissolving tank warm, and the temperature range of the liquid in the dissolving tank is 95°C to 100°C.

[0015] Furthermore, an oxidant is added to the dissolution tank through the oxidant feeding port, and the oxidant is sodium persulfate, sodium hypochlorite or hydrogen peroxide. The ratio of the added amount of the oxidant to the total mass of organic matter in the mixed salt solution in the dissolution tank is in the range of 2:1 to 3:1.

[0016] Furthermore, the heat exchanger includes an outer shell and a heat exchange coil arranged in the outer shell, the heat exchange medium inlet, heat exchange medium outlet, water injection port and water supply port are all arranged on the outer shell, one end of the heat exchange coil is installed at the heat exchange medium inlet, and the other end of the heat exchange coil is installed at the heat exchange medium outlet.

[0017] Furthermore, the cooling evaporation device also has an air outlet and a condensed water outlet, the air outlet is connected to the vacuum pump, and the condensed water outlet is connected to the condensed water tank.

[0018] Furthermore, the condensed water tank has a first inlet, a second inlet and a water outlet, the first inlet is connected to the condensed water outlet on the insulation jacket, the second inlet is connected to the condensed water outlet of the cooling evaporation device, and the water outlet is connected to the water inlet of the heat exchanger.

[0019] Furthermore, the cooling evaporation device includes a pressure tank and a heat-insulating jacket arranged outside the pressure tank, and the heat-insulating jacket is used to continuously keep the liquid in the pressure tank warm. The temperature range of the liquid in the pressure tank is 40°C to 50°C.

[0020] Furthermore, the vacuum degree of the pressure tank ranges from 0.001 MPa to 0.01 MPa.

[0021] Furthermore, the dissolving tank is provided with a stirrer, and the stirrer is used to stir the liquid in the dissolving tank.

[0022] Furthermore, the dissolving tank is provided with a thermometer and a liquid level gauge, the thermometer is used to measure the temperature of the liquid in the dissolving tank, and the liquid level gauge is used to measure the liquid level of the liquid in the dissolving tank.

[0023] Furthermore, the desuperheating evaporation device is provided with a stirrer, and the stirrer is used to stir the liquid in the desuperheating evaporation device.

[0024] Furthermore, the desuperheating evaporation device is provided with a thermometer and a liquid level gauge, the thermometer is used to measure the temperature of the liquid in the desuperheating evaporation device, and the liquid level gauge is used to measure the liquid level of the liquid in the desuperheating evaporation device.

[0025] Furthermore, the desuperheating evaporation device is provided with a pressure gauge.

[0026] Compared with the prior art, this application has at least the following beneficial effects:

[0027] The present application provides a low-energy separation system for the recovery of sodium chloride and sodium sulfate, which mainly consists of a dissolving tank, a first centrifuge, a heat exchanger, a cooling evaporation device, a second centrifuge, a condensed water tank and a vacuum pump. The dissolving tank is provided with an oxidant feeding port and a mixed salt liquid feeding port. The oxidant is used to eliminate organic matter in the mixed salt, while ensuring that the system is in a supersaturated state, and the undissolved salt is sodium sulfate. Therefore, the system takes into account the problem that the presence of organic matter in the mixed salt will affect the quality of the crystallized salt. By adding an oxidant, the organic matter is oxidized while the mixed salt is dissolved, and no impurity ions are introduced, thereby completing the recovery of sodium sulfate. The sodium chloride is precipitated, and then the sodium sulfate and the mother liquor are separated by the first centrifuge. The mother liquor is then sent to a heat exchanger to complete heat exchange and cooling with condensed water. The cooled mother liquor is evaporated at a negative pressure and low temperature in a cooling evaporator. After sodium chloride is precipitated, the sodium chloride and the tail liquid are separated by a second centrifuge. The tail liquid can be sent to a dissolving tank for further treatment. Therefore, this system utilizes the solubility characteristics of the sodium chloride-sodium sulfate-water ternary system at different temperatures to recycle sodium chloride and sodium sulfate, and utilizes a heat exchanger to realize heat recovery of the mother liquor, and uses the heat to heat the dissolving tank inlet water, thereby reducing energy consumption and realizing low-energy consumption and low-cost resource recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing the present application; for example, based on the technical concepts and exemplary drawings disclosed in this application, those skilled in the art are able to easily make routine adjustments or further optimizations to the addition / reduction / attribution division, specific shapes, positional relationships, connection methods, and dimensional ratios of certain units (components).

[0029] Figure 1 The present invention provides a schematic diagram of the structural principle of a low-energy separation system for recovering sodium chloride and sodium sulfate in accordance with an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1. Dissolving tank; 11. Steam inlet; 12. Condensate outlet; 13. Oxidant feed port; 14. Mixed salt solution feed port; 15. Tail liquid return port; 16. Water inlet; 17. Discharge port;

[0032] 2. First centrifuge; 21. Feed inlet; 22. Sodium sulfate outlet; 23. Mother liquor outlet;

[0033] 3. Heat exchanger; 31. Heat exchange medium inlet; 32. Heat exchange medium outlet; 33. Water injection port; 34. Water supply port;

[0034] 4. Cooling evaporation device; 41. Mother liquor inlet; 42. Discharge port; 43. Gas outlet; 44. Condensate outlet;

[0035] 5. Second centrifuge; 51. Liquid inlet; 52. Sodium chloride outlet; 53. Tail liquid outlet;

[0036] 6. Condensate tank;

[0037] 7. Vacuum pump. DETAILED DESCRIPTION

[0038] The present application will be further described below in detail through specific embodiments in conjunction with the accompanying drawings.

[0039] In the description of this application: unless otherwise specified, the meaning of "plurality" is two or more. The terms "first", "second", etc. in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (for example, they should not be understood as emphasizing the degree of importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0040] In order to solve the problems existing in the prior art, the present application provides a low-energy separation system for the recovery of sodium chloride and sodium sulfate. When treating mixed salt (mainly containing NaCl, Na2SO4 and organic matter to be treated, mostly industrial wastewater), the presence of organic matter will affect the quality of the crystalline salt. Therefore, the system adds a suitable oxidant without introducing impurity ions to oxidize the organic matter while dissolving the mixed salt. The system mainly utilizes the solubility characteristics of the sodium chloride-sodium sulfate-water ternary system at different temperatures. Under low temperature difference conditions, sodium sulfate solid and sodium chloride solid are separated in turn. Considering that water has a large specific heat capacity, excessive temperature difference will cause energy loss. Therefore, the present application also uses a heat exchanger to recycle the mother liquor waste heat in the disposal process to reduce the energy consumption of the treatment process and reduce the treatment cost. The system structure and separation process of a low-energy separation system for the recovery of sodium chloride and sodium sulfate provided by the present application are described in detail in combination with specific embodiments.

[0041] Example 1

[0042] See also Figure 1The present embodiment provides a low-energy separation system for recovering sodium chloride and sodium sulfate, which mainly includes a dissolving tank 1, a first centrifuge 2, a heat exchanger 3, a cooling evaporation device 4, a second centrifuge 5, a condensed water tank 6 and a vacuum pump 7. Among them, the dissolving tank 1 and the first centrifuge 2 cooperate to realize the extraction and separation of sodium sulfate in the mixed salt liquid, and the cooling evaporation device 4 and the second centrifuge 5 cooperate to realize the extraction and separation of sodium chloride in the mother liquor (brine mixture liquid) discharged from the first centrifuge 2. Since there is a high temperature difference between the liquid temperature in the dissolving tank 1 and the liquid temperature in the cooling evaporation device 4, the present application sets a heat exchanger 3 to recover the temperature of the mother liquor discharged from the first centrifuge 2, and uses the recovered heat to heat the water passed into the dissolving tank 1, thereby reducing the energy consumption of maintaining the liquid temperature in the dissolving tank 1. The vacuum pump 7 is used to ensure the negative pressure state of the cooling evaporation device 4, and the condensed water tank 6 is used to collect the condensed water in the insulation jacket of the dissolving tank 1 and the condensed water evaporated by the cooling evaporation device 4. The water in the condensed water tank 6 can be heated by the heat exchanger 3 and then reused in the dissolving tank 1. Of course, an external water source can also be added to cooperate with the condensed water tank 6 to add water to the dissolving tank 1 at the same time, ensuring that the amount of water added meets the requirements.

[0043] In this embodiment, the dissolving tank 1 includes a tank body and an insulating jacket arranged outside the tank body. The insulating jacket is provided with a steam inlet 11 and a condensed water outlet 12. Steam is introduced into the insulating jacket to continuously keep the liquid in the dissolving tank 1 warm, so that the water temperature in the dissolving tank 1 is maintained at 95°C, and the steam condensed water is discharged from the condensed water outlet 12 to the condensed water tank 6.

[0044] In this embodiment, the dissolving tank 1 is a reaction tank, and an oxidant, a mixed salt solution, and water are sequentially added to the dissolving tank 1 through the oxidant feeding port 13, the mixed salt solution feeding port 14, and the water inlet 16 provided thereon. In addition, the dissolving tank 1 is also provided with a water inlet 16 and a discharge port 17, and the discharge port 17 is connected to the first centrifuge 2. In this embodiment, the oxidant added to the dissolving tank 1 is sodium persulfate, and the mass ratio of the amount of sodium persulfate added to all organic matter in the mixed salt solution is 2:1. When the mixed salt solution and the oxidant are added to the dissolving tank 1 and the dissolution reaction is sufficient, the oxidant can eliminate the organic matter in the mixed salt, while ensuring that the system is in a supersaturated state, and the undissolved salt is solid sodium sulfate.

[0045] In this embodiment, the first centrifuge 2 has a feed port 21, a sodium sulfate discharge port 22 and a mother liquor discharge port 23. The feed port 21 of the first centrifuge 2 is connected to the discharge port 17 of the dissolving tank 1. The first centrifuge 2 separates the solid sodium sulfate from the mother liquor.

[0046] In this embodiment, the cooling evaporation device 4 can evaporate solid sodium chloride at low temperature. The cooling evaporation device 4 has a mother liquid inlet 41, a discharge port 42, an air outlet 43 and a condensate outlet 44. The heat exchanger 3 has a heat exchange medium inlet 31, a heat exchange medium outlet 32, a water injection port 33 and a water supply port 34. Figure 1 The mother liquor discharge port 23 of the first centrifuge 2 is connected to the heat exchange medium inlet 31, the heat exchange medium outlet 32 ​​is connected to the mother liquor inlet 41 of the cooling evaporation device 4, the water injection port 33 is connected to the condensed water tank 6, and the water supply port 34 is connected to the water inlet 16 of the dissolution tank 1; the discharge port 42 of the cooling evaporation device 4 is connected to the liquid inlet 51 of the second centrifuge 5, and the mixed liquid containing solid sodium chloride is fed into the second centrifuge 5 for solid-liquid separation. The air outlet 43 is connected to the vacuum pump 7, and the condensed water outlet 44 is connected to the condensed water tank 6.

[0047] In this embodiment, the second centrifuge 5 has a liquid inlet 51, a sodium chloride outlet 52 and a tail liquid outlet 53. The second centrifuge 5 is used to separate the tail liquid and the sodium chloride solid. The sodium chloride solid is discharged from the sodium chloride outlet 52 to a collection point, and the tail liquid from which the sodium chloride solid is separated is discharged to the dissolution tank 1 through the tail liquid outlet 53 for further processing.

[0048] In this embodiment, the heat exchanger 3 includes an outer shell and a heat exchange coil arranged in the outer shell. The heat exchange medium inlet 31, the heat exchange medium outlet 32, the water injection port 33 and the water supply port 34 are all arranged on the outer shell. One end of the heat exchange coil is installed at the heat exchange medium inlet 31, and the other end of the heat exchange coil is installed at the heat exchange medium outlet 32. After the condensed water is passed into the outer shell and heat-exchanged with the mother liquid in the heat exchange coil to heat it up, it is sent into the dissolution tank 1 from the water supply port 34 on the outer shell to realize the heat recovery and utilization of the mother liquid.

[0049] In this embodiment, the cooling evaporation device 4 includes a pressure tank and an insulation jacket arranged outside the pressure tank. The insulation jacket can continuously keep the liquid in the pressure tank warm. The temperature range of the liquid in the pressure tank is 40°C. The vacuum pump 7 can maintain the vacuum degree of the pressure tank at 0.001MPa.

[0050] In this embodiment, a stirrer can be provided in both the dissolving tank 1 and the cooling evaporation device 4, and a thermometer and a liquid level gauge can be provided on the dissolving tank 1 and the cooling evaporation device 4 respectively. A pressure gauge can also be provided in the cooling evaporation device 4.

[0051] The low-energy separation system for recovering sodium chloride and sodium sulfate provided in the present application has the following working process: a mixed salt solution and an oxidant are added to a dissolving tank 1. After sufficient dissolution reaction, the oxidant eliminates organic matter in the mixed salt solution, while ensuring that the system is in a supersaturated state, and the undissolved salt is sodium sulfate. The salt mixture enters the first centrifuge 2 for separation, and the separated solid is anhydrous sodium sulfate. The mother liquor in the first centrifuge 2 enters the heat exchanger 3 for heat exchange and cooling. The cooled mother liquor enters the cooling evaporation device 4. The vacuum pump 7 can ensure that the cooling evaporation device 4 is in a negative pressure state. The mother liquor in the cooling evaporation device 4 evaporates at low temperature. The evaporated liquid enters the second centrifuge 5 for separation. The separated solid is sodium chloride, and the tail liquid in the second separator is returned to the dissolving tank 1. In this system, the condensed water generated by the steam used to heat the material in the dissolving tank 1 after cooling and the condensed water evaporated by the cooling evaporation device 4 can be collected in the condensed water tank 6. The water in the condensed water tank 6 is preheated by the heat exchanger 3 and enters the dissolving tank 1.

[0052] Example 2

[0053] This embodiment provides a low-energy separation system for recovering sodium chloride and sodium sulfate. The system's structural principles are the same as those of Example 1, with the following differences: In this embodiment, the water temperature in dissolution tank 1 is maintained at 98°C, and the oxidant added to dissolution tank 1 is sodium hypochlorite, with a mass ratio of sodium hypochlorite to total organic matter in the mixed salt solution of 2.5:1. The liquid temperature in cooling evaporation device 4 is maintained at 45°C, and the vacuum level in cooling evaporation device 4 is 0.005 MPa.

[0054] Example 3

[0055] This embodiment provides a low-energy separation system for recovering sodium chloride and sodium sulfate. The system's structural principles are the same as those of Example 1, with the following differences: In this embodiment, the water temperature in dissolution tank 1 is maintained at 100°C, and the oxidant added to dissolution tank 1 is hydrogen peroxide, with a mass ratio of hydrogen peroxide to total organic matter in the mixed salt solution of 3:1. The liquid temperature in cooling evaporation device 4 is maintained at 50°C, and the vacuum level in cooling evaporation device 4 is 0.01 MPa.

[0056] In summary, the present application provides a low-energy separation system for the recovery of sodium chloride and sodium sulfate, which is mainly composed of a dissolving tank, a first centrifuge, a heat exchanger, a cooling evaporation device, a second centrifuge, a condensed water tank and a vacuum pump. The dissolving tank is provided with an oxidant feeding port and a mixed salt liquid feeding port. The oxidant is used to eliminate organic matter in the mixed salt, while ensuring that the system is in a supersaturated state, and the undissolved salt is sodium sulfate. Therefore, the system takes into account the problem that the presence of organic matter in the mixed salt will affect the quality of the crystallized salt. By adding an oxidant, the organic matter is oxidized while the mixed salt is dissolved, and no impurity ions are introduced, thereby completing the recovery of sodium sulfate. The sodium sulfate and the mother liquor are separated by a first centrifuge, and the mother liquor is then sent to a heat exchanger to complete heat exchange and cooling with condensed water. The cooled mother liquor is evaporated at a negative pressure and low temperature in a cooling evaporator. After sodium chloride is precipitated, the sodium chloride and the tail liquid are separated by a second centrifuge, and the tail liquid can be sent to a dissolving tank for further treatment. Therefore, this system utilizes the solubility characteristics of the sodium chloride-sodium sulfate-water ternary system at different temperatures to sequentially recover the resources of sodium sulfate and sodium chloride, and utilizes a heat exchanger to realize heat recovery of the mother liquor, and uses the heat to heat the water in the dissolving tank, thereby reducing energy consumption and realizing low-energy consumption and low-cost resource recovery.

[0057] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

[0058] The present application has been described in a relatively specific and detailed manner through general explanations and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations may be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by such conventional adjustments or further innovations also fall within the scope of protection of the claims of the present application.

Claims

1. A low energy consumption separation system for the recovery of sodium chloride and sodium sulfate, characterized in that: It includes a dissolving tank, a first centrifuge, a heat exchanger, a cooling evaporation device, a second centrifuge, a condensed water tank and a vacuum pump, wherein: The dissolving tank comprises a tank body and a heat-insulating jacket arranged outside the tank body, wherein the tank body is provided with an oxidant feeding port, a mixed salt liquid feeding port, a tail liquid return port, a water inlet and a discharge port; The first centrifuge has a feed inlet, a sodium sulfate discharge outlet and a mother liquor discharge outlet, and the feed inlet is connected to the discharge outlet of the dissolving tank; The heat exchanger has a heat exchange medium inlet, a heat exchange medium outlet, a water injection port and a water supply port, the mother liquid discharge port is connected to the heat exchange medium inlet, the heat exchange medium outlet is connected to the mother liquid inlet of the temperature reduction evaporation device, the water injection port is connected to the condensed water tank, and the water supply port is connected to the water inlet; The discharge port of the desuperheating evaporation device is connected to the liquid inlet of the second centrifuge, and the tail liquid discharge port of the second centrifuge is connected to the tail liquid return port.

2. The low energy consumption separation system for recovery of sodium chloride and sodium sulfate according to claim 1, characterized in that: The thermal insulation jacket is provided with a steam inlet and a condensed water outlet. The thermal insulation jacket is used to continuously keep the liquid in the dissolving tank warm. The temperature range of the liquid in the dissolving tank is 95° C. to 100° C.

3. The low energy consumption separation system for recovery of sodium chloride and sodium sulfate according to claim 1, characterized in that: An oxidant is added into the dissolving tank through the oxidant feeding port, wherein the oxidant is sodium persulfate, sodium hypochlorite or hydrogen peroxide.

4. The low energy consumption separation system for recovery of sodium chloride and sodium sulfate according to claim 1, characterized in that: The heat exchanger includes an outer shell and a heat exchange coil arranged in the outer shell. The heat exchange medium inlet, heat exchange medium outlet, water injection port and water supply port are all arranged on the outer shell. One end of the heat exchange coil is installed at the heat exchange medium inlet, and the other end of the heat exchange coil is installed at the heat exchange medium outlet.

5. The low energy consumption separation system for recovery of sodium chloride and sodium sulfate according to claim 2, characterized in that: The temperature-reducing evaporation device further comprises an air outlet and a condensed water outlet, wherein the air outlet is connected to the vacuum pump, and the condensed water outlet is connected to the condensed water tank.

6. The low energy consumption separation system for recovering sodium chloride and sodium sulfate according to claim 5, characterized in that: The condensed water tank has a first inlet, a second inlet and a water outlet, the first inlet is connected to the condensed water outlet on the insulation jacket, the second inlet is connected to the condensed water outlet of the cooling evaporation device, and the water outlet is connected to the water inlet of the heat exchanger.

7. The low energy consumption separation system for recovering sodium chloride and sodium sulfate according to claim 1, characterized in that: The cooling evaporation device includes a pressure tank and an insulation jacket arranged outside the pressure tank. The insulation jacket is used to continuously keep the liquid in the pressure tank warm. The temperature range of the liquid in the pressure tank is 40°C to 50°C, and the vacuum range of the pressure tank is 0.001MPa to 0.01MPa.

8. The low energy consumption separation system for recovering sodium chloride and sodium sulfate according to claim 1, characterized in that: The dissolving tank is provided with a stirrer, and the stirrer is used to stir the liquid in the dissolving tank; The dissolving tank is provided with a thermometer and a liquid level gauge, wherein the thermometer is used to measure the temperature of the liquid in the dissolving tank, and the liquid level gauge is used to measure the liquid level of the liquid in the dissolving tank.

9. The low energy consumption separation system for recovering sodium chloride and sodium sulfate according to claim 1, characterized in that: The desuperheating evaporation device is provided with a stirrer, and the stirrer is used to stir the liquid in the desuperheating evaporation device; The desuperheating evaporation device is provided with a thermometer and a liquid level gauge, wherein the thermometer is used to measure the temperature of the liquid in the desuperheating evaporation device, and the liquid level gauge is used to measure the liquid level of the liquid in the desuperheating evaporation device; The desuperheating evaporation device is provided with a pressure gauge.

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