Nanofiltration membrane and heat pump combined energy tower organic salt solution treatment system and method

Abstract

The invention provides a nanofiltration membrane and heat pump combined energy tower organic salt solution treatment system and method. The system comprises a heat pump system and a nanofiltration membrane system; the heat pump system comprises a refrigerant loop, a solution loop, a circulating air loop and a freezing dehumidification loop; the refrigerant loop comprises a compressor, a first heat exchanger, a second heat exchanger, a throttling valve and an evaporator which are sequentially connected through a conveying pipeline to form a loop. The solution loop comprises a solution boiling regenerator, an energy tower, a first solution circulation secondary water pump, a second solution circulation secondary water pump, a hot solution circulation pump and a second heat exchanger which are sequentially connected through a conveying pipeline to form the loop, and the first heat exchanger directly sinks in the solution boiling regenerator. The problem that the solution concentration capacity of the nanofiltration membrane is reduced in a low-temperature environment is solved by utilizing the heat pump, so that the organic salt solution of the energy tower can be continuously concentrated to meet the anti-freezing salinity requirement after absorbing heat in air and feeding water to dilute the solution concentration in the low-temperature environment.

Description

Technical Field

[0001] This invention belongs to the field of energy tower salt solution regeneration technology, and specifically relates to an energy tower organic salt solution treatment system and method combining nanofiltration membrane and heat pump. Background Technology

[0002] Heat pump technology is a new type of energy-saving air conditioning technology promoted by the state. Currently, air-cooled heat pump air conditioners dominate the market because their surface cooling heat exchange efficiency is not high. Energy tower heat pumps utilize the latent heat exchange between a water tower and the air, resulting in cooling and heating efficiency far exceeding that of air-cooled heat pumps, almost comparable to ground source heat pumps. However, they are not limited by the underground environment or subject to underground pollution losses, making them an ideal high-efficiency heat pump air conditioner. The key to energy tower heat pumps is the regeneration of the salt solution, primarily used to remove moisture from the salt solution during winter heating in ambient temperatures ranging from -15°C to -15°C, thus meeting the solution's antifreeze requirements.

[0003] The prior art, application number 2017217637088, discloses a regeneration technology using a membrane to separate solutions, including a reverse osmosis membrane. However, electrodialysis is only suitable for ambient temperatures >15℃. In winter, when the outdoor ambient temperature is <0℃, the above method is completely unusable. Below 0℃, the efficiency of electrodialysis drops significantly, rendering it uneconomical. Furthermore, reverse osmosis membranes are only suitable for low-concentration salts (TDS <5%) and cannot be used for energy tower heat pump salt solution treatment (TDS reaches 17%-25%).

[0004] The prior art with application number 2019103918802 discloses a technical solution for evaporating and condensing water from a salt solution using a heat pump compressor. Since the regeneration of the salt solution mainly occurs in winter, and the heat exchange temperature difference of the energy tower heat pump is relatively small in winter, generally 2.5-3.5℃, the cost of using a heat pump compressor to regenerate the salt solution is high, and it does not achieve economic and energy-saving use. This is mainly because the salt needs to evaporate and the temperature is high, which increases the power consumption of the compressor.

[0005] Existing technologies cannot achieve low-cost, environmentally friendly salt solution regeneration, which limits the development of energy tower heat pump products. Summary of the Invention

[0006] Based on this, the purpose of this invention is to provide an energy tower organic salt solution treatment system and method combining nanofiltration membrane and heat pump, in order to solve the technical problems mentioned in the background above.

[0007] A first aspect of the present invention provides an energy tower organic salt solution treatment system combining a nanofiltration membrane and a heat pump, comprising a heat pump system and a nanofiltration membrane system; wherein, A heat pump system includes a refrigerant circuit, a solution circuit, a circulating air circuit, and a refrigeration and dehumidification circuit; among which, The refrigerant circuit includes a compressor, a first heat exchanger, a second heat exchanger, a throttle valve, and an evaporator, which are connected in sequence through transport pipelines to form a circuit; The solution loop includes a solution boiling regenerator, an energy tower, a first solution circulation secondary water pump, a second solution circulation secondary water pump, a hot solution circulation pump, and a second heat exchanger, which are connected in sequence through transport pipelines to form a loop. The first heat exchanger is directly submerged in the solution boiling regenerator. The circulating air circuit includes a solution boiling regenerator and a circulating fan, which are connected in a loop through circulating air ducts; The nanofiltration membrane system includes a solution circulation primary water pump, nanofiltration membrane equipment, a high-pressure pump, a nanofiltration membrane stack, and solenoid valves, which are connected in sequence to form a loop through transport pipelines.

[0008] Preferably, the heat pump system also includes a vacuum maintenance circuit to maintain the vacuum state of the gas circuit and the solution boiling regenerator, thereby reducing the solution evaporation temperature.

[0009] Preferably, the vacuum maintenance circuit includes a vacuum pump, a pressure regulating valve, and a pressure regulating tank. The gas from the solution boiling regenerator is connected to the inlet of the pressure regulating valve, the outlet of the pressure regulating valve is connected to the inlet of the pressure regulating tank, and the outlet of the pressure regulating tank is connected to the inlet of the vacuum pump.

[0010] Preferably, both the first heat exchanger and the second heat exchanger are titanium tube shell-and-tube heat exchangers.

[0011] Preferably, in the solution circuit, the outlet of the solution boiling regenerator is connected to the inlet of the heating solution circulation pump. The outlet of the heating solution circulation pump is divided into two circuits: one circuit is connected to the inlet of the solenoid valve, and the outlet of the solenoid valve is connected in parallel with the concentrated solution outlet of the nanofiltration membrane device; the other circuit of the outlet of the heating solution circulation pump is connected to the raw water inlet of the nanofiltration membrane device, and the concentrated solution outlet of the nanofiltration membrane device is connected in parallel with the outlet of the solenoid valve and then connected to the inlet of the solution boiling regenerator.

[0012] Preferably, in the nanofiltration membrane system, the outlet of the energy tower is connected to the inlet of the second solution circulation secondary water pump, the outlet of the second solution circulation secondary water pump is connected to the inlet of the second heat exchanger, and the outlet of the second heat exchanger is connected to the other inlet X1 of the solution boiling regenerator. The other outlet X2 of the solution boiling regenerator is connected to the inlet of the first solution circulation secondary water pump, and the outlet of the first solution circulation secondary water pump is connected to the inlet of the energy tower.

[0013] Preferably, in the circulating air circuit, the evaporator is installed inside the circulating air duct, and the gas in the solution boiling regenerator is drawn by the circulating fan through the evaporator and then flows back into the solution boiling regenerator.

[0014] Preferably, it also includes a refrigeration dehumidification circuit, which includes an evaporator, a water tank, a normally open valve, and an electric valve, connected in sequence through a transport pipeline to form a circuit for refrigeration dehumidification and discharge of condensate; in the refrigeration dehumidification circuit, a normally open valve is installed between the evaporator and the water tank, and an electric valve is connected to the outlet of the water tank for discharging condensate.

[0015] Preferably, in the refrigerant circuit, the compressor outlet discharges hot gas to the inlet of the first heat exchanger, and the outside of the first heat exchanger directly heats the salt solution; the outlet of the first heat exchanger is connected to the inlet of the second heat exchanger, and the secondary side of the second heat exchanger heats the salt solution from the energy tower; the outlet of the second heat exchanger is connected to a throttling valve, which is used to regulate the refrigerant flow rate; the outlet of the throttling valve is connected to the inlet of the evaporator, where the evaporator absorbs heat at low temperature, causing water vapor to condense into water; the outlet of the evaporator is connected to a liquid receiver, which is connected to the compressor, completing one cycle.

[0016] A second aspect of the present invention provides a method for treating organic salt solutions, employing an energy tower organic salt solution treatment system combining a nanofiltration membrane and a heat pump as described in any of the preceding claims, specifically comprising: Step (1): First, start the vacuum pump and adjust the pressure regulating valve to maintain the pressure regulating tank at a vacuum of -5 Pa or higher. Step (2): Start the second solution circulation secondary water pump so that the salt solution in the energy tower flows through the second heat exchanger for heat exchange, and then flows into the solution boiling regenerator; Step (3): Start the solution circulation pump so that the liquid output of the solution boiling regenerator flows into the nanofiltration membrane equipment through the solution circulation primary water pump for ion and water separation. The concentrated solution after separation flows back into the solution boiling regenerator. The liquid output end X2 of the solution boiling regenerator is connected to the inlet end of the solution circulation secondary water pump. The liquid output end of the solution circulation secondary water pump is connected to the liquid input end of the energy tower to form a solution loop circulation. Step (4): Start the refrigeration circuit. First, start the compressor. The compressor discharges hot gas to the first heat exchanger, which heats the salt solution. The outlet of the first heat exchanger is connected to the inlet of the second heat exchanger, which heats the salt solution. The secondary side of the second heat exchanger heats the salt solution from the energy tower. The outlet of the second heat exchanger is connected to the inlet of the evaporator, which dehumidifies and removes water, thus concentrating the solution. Step (5): Once the salinity of the concentrated solution is reached, the control system issues a shutdown command, first shutting down the nanofiltration membrane equipment; Step (6): After confirming that the nanofiltration membrane equipment is shut down, shut down the refrigeration circuit, first shut down the compressor, and then shut down the circulating fan; Step (7): Turn off the solution circulation pumps sequentially; Step (8): Shut down the secondary water pump for solution circulation; Step (9): Shut down the vacuum pump.

[0017] The present invention can achieve the following beneficial effects: This invention utilizes a heat pump to solve the problem of reduced solution concentration capacity of nanofiltration membranes at low temperatures. This ensures that, even at low temperatures, after the organic salt solution in the energy tower absorbs heat from the air and is diluted with water, the concentration can be continuously increased to meet the antifreeze salinity requirements because the nanofiltration membrane's solution concentration capacity is sufficient. The heat pump addresses the operating conditions of the nanofiltration membrane and also utilizes hot and cold evaporation to cool, dehumidify, and concentrate the salt solution.

[0018] This invention employs two major systems—a heat pump system and a nanofiltration membrane system—operating in a highly energy-efficient manner under the control of salinity and temperature acquisition. While the heat pump's high-temperature evaporation and low-temperature cooling dehumidification are relatively energy-intensive, their energy consumption is low once the nanofiltration membrane reaches its operating conditions. Once these conditions are met, the nanofiltration membrane achieves high efficiency in dehumidifying and concentrating the salt solution. In this way, the heat pump system and the nanofiltration membrane system work together in an optimized manner to achieve economical concentration capabilities. Attached Figure Description

[0019] Figure 1 This is a system diagram of the present invention.

[0020] In the diagram: 1. Compressor; 2. First heat exchanger; 3. Second heat exchanger; 4. Throttling valve; 5. Evaporator; 6. Liquid receiver; 7. Circulating fan; 8. Solution boiling regenerator; 9. Nanofiltration membrane equipment; 10. Primary solution circulation pump; 11. Secondary solution circulation pump; 12. Energy tower; 13. Water storage tank; 14. Normally open valve; 15. Electric valve; 16. Circulating air duct; 17. Pressure regulating valve; 18. Pressure regulating tank; 19. Vacuum pump; 20. High-pressure pump; 21. Nanofiltration membrane stack; 22. Secondary solution circulation pump; 23. Solenoid valve; 24. Salinity sensor; 25. Ultrafiltration unit; 26. Pressure reducing valve. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 As shown in the figure, the orange arrows represent the flow direction of the solution, and the green arrows represent the flow direction of the refrigerant. This invention provides an energy tower organic salt solution treatment system combining a nanofiltration membrane and a heat pump, comprising a heat pump system and a nanofiltration membrane system; wherein, A heat pump system includes a refrigerant circuit, a solution circuit, a circulating air circuit, and a refrigeration and dehumidification circuit; among which, The refrigerant circuit includes compressor 1, first heat exchanger 2, second heat exchanger 3, expansion valve 4 and evaporator 5, which are connected in sequence through transport pipelines to form a circuit; The solution loop includes a solution boiling regenerator 8, an energy tower 12, a first solution circulation secondary water pump 22, a second solution circulation secondary water pump 11, a hot solution circulation pump 10, and a second heat exchanger 3, which are connected in sequence through transport pipelines to form a loop. The first heat exchanger 2 is directly submerged in the solution boiling regenerator 8. The circulating air circuit includes a solution boiling regenerator 8 and a circulating fan 7, which are connected in a loop through a circulating air duct 16. The nanofiltration membrane system includes a solution circulation primary water pump 10, a nanofiltration membrane device 9, a high-pressure pump 20, a nanofiltration membrane stack 21, and a solenoid valve 23, which are connected in sequence to form a loop through transport pipelines. A salinity sensor 24 is installed at the bottom of the solution boiling regenerator 8 to detect the salinity of the solution.

[0023] As is known, the nanofiltration membrane device 9 in this invention is a pressure-driven separation device based on a nanofiltration membrane (pore size between 0.5-10 nanometers, between ultrafiltration membrane and reverse osmosis membrane). Its core function is to achieve selective separation of small molecule organic matter, multivalent ions and water / monovalent ions, and it also has the functions of "purification", "concentration" and "impurity removal". In the implementation stage of this invention, the 8040 model nanofiltration membrane device of Guangdong Jucheng Bayer Co., Ltd. was used.

[0024] Both the first heat exchanger 2 and the second heat exchanger 3 are preferably titanium tube shell-and-tube heat exchangers.

[0025] Specifically, the heat pump system also includes a vacuum maintenance loop, which is used to maintain the vacuum state of the gas loop and the solution boiling regenerator 8, thereby reducing the solution evaporation temperature.

[0026] The vacuum maintenance circuit includes a vacuum pump 19, a pressure regulating valve 17, and a pressure regulating tank 18. The gas from the solution boiling regenerator 8 is connected to the inlet of the pressure regulating valve 17, the outlet of the pressure regulating valve 17 is connected to the inlet of the pressure regulating tank 18, and the outlet of the pressure regulating tank 18 is connected to the inlet of the vacuum pump 19.

[0027] In the solution loop, the outlet of the solution boiling regenerator 8 is connected to the inlet of the heating solution circulation pump 10. The outlet of the heating solution circulation pump 10 is divided into two loops: one loop is connected to the inlet of the solenoid valve 23, and the outlet of the solenoid valve 23 is connected in parallel with the concentrated solution outlet of the nanofiltration membrane device; the other loop of the outlet of the heating solution circulation pump 10 is connected to the raw water inlet of the nanofiltration membrane device, and the concentrated solution outlet of the nanofiltration membrane device is connected in parallel with the outlet of the solenoid valve 23 and then connected to the inlet of the solution boiling regenerator 8.

[0028] In the nanofiltration membrane system, the outlet of the energy tower 12 is connected to the inlet of the second solution circulation secondary water pump 11, the outlet of the second solution circulation secondary water pump 11 is connected to the inlet of the second heat exchanger 3, and the outlet of the second heat exchanger 3 is connected to the other inlet X1 of the solution boiling regenerator 8. The other outlet X2 of the solution boiling regenerator 8 is connected to the inlet of the first solution circulation secondary water pump 22, and the outlet of the first solution circulation secondary water pump 22 is connected to the inlet of the energy tower 12.

[0029] In the circulating air circuit, the evaporator 5 is installed in the circulating air duct 16, and the gas in the solution boiling regenerator 8 is guided by the circulating fan 7 through the evaporator 5 and then flows back to the solution boiling regenerator 8.

[0030] In some preferred embodiments, a refrigeration dehumidification circuit is also included. The refrigeration dehumidification circuit includes an evaporator 5, a water tank 13, a normally open valve 14, and an electric valve 15, which are connected in sequence through a transport pipeline to form a circuit for refrigeration dehumidification and discharge of condensate. In the refrigeration dehumidification circuit, a normally open valve 14 is provided between the evaporator 5 and the water tank 13, and an electric valve 15 is connected to the outlet of the water tank 13. The electric valve 15 is used to discharge condensate.

[0031] In the refrigerant circuit, the outlet of compressor 1 discharges hot gas to the inlet of the first heat exchanger 2, and the outside of the first heat exchanger 2 directly heats the salt solution. The outlet of the first heat exchanger 2 is connected to the inlet of the second heat exchanger 3. The secondary side of the second heat exchanger 3 heats the salt solution from the energy tower. The outlet of the second heat exchanger 3 is connected to the expansion valve 4, which is used to regulate the refrigerant flow rate. The outlet of the expansion valve 4 is connected to the inlet of the evaporator 5. The evaporator 5 absorbs heat at low temperature, causing water vapor to condense into water. The outlet of the evaporator 5 is connected to the liquid receiver 6, which is connected to the compressor 1, completing one cycle.

[0032] The nanofiltration membrane system is a part of the solution loop, specifically: the outlet of the solution boiling regenerator 8 is connected to the inlet of the heating solution circulation pump 10. The outlet of the heating solution circulation pump 10 is divided into two loops: one loop is connected to the inlet of the solenoid valve 23, and the outlet of the solenoid valve 23 is connected in parallel with the concentrated solution outlet of the nanofiltration membrane device. The other loop of the outlet of the heating solution circulation pump 10 is connected to the raw water inlet of the nanofiltration membrane device 9, and the concentrated solution outlet of the nanofiltration membrane device 9 is connected in parallel with the outlet of the solenoid valve 23. The concentrated solution outlet of the nanofiltration membrane device 9, after being connected in parallel with the outlet of the solenoid valve 23, is then connected to the inlet of the solution boiling regenerator 8.

[0033] Inside the nanofiltration membrane equipment: The raw water inlet of the nanofiltration membrane equipment is connected to the inlet of the ultrafiltration 25 (composed of <0.01um filter material), the outlet of the ultrafiltration 25 is connected to the inlet of the high-pressure water pump 20, the outlet of the high-pressure water pump 20 is connected to the inlet of the nanofiltration membrane stack 21, the outlet of the nanofiltration membrane stack 21 is connected to the inlet of the pressure reducing valve 26, and the outlet of the pressure reducing valve 26 is connected to the concentrated solution outlet of the nanofiltration membrane equipment 9.

[0034] The process of using the system in this invention, namely a method for treating organic salt solutions, specifically includes: Step (1): First, start the vacuum pump 19 and adjust the pressure regulating valve 17 to maintain the pressure regulating tank 18 at a vacuum of -5pa or higher. Step (2): Start the second solution circulation secondary water pump 11 so that the salt solution in the energy tower 12 flows through the second heat exchanger (3) for heat exchange, and then flows into the solution boiling regenerator 8; Step 3: Start the solution circulation pump 10 so that the liquid output of the solution boiling regenerator 8 flows into the nanofiltration membrane device through the solution circulation primary water pump (10) for ion and water separation. The concentrated solution after separation flows back into the solution boiling regenerator 8. The liquid output X2 of the solution boiling regenerator 8 is connected to the inlet of the solution circulation secondary water pump 22. The liquid output of the solution circulation secondary water pump 22 is connected to the liquid output of the energy tower 12 to form a solution loop circulation. Step (4): Start the refrigeration circuit. First, start the compressor 1. The outlet of the compressor 1 discharges hot gas to the first heat exchanger 2, so that the first heat exchanger 2 heats the salt solution. The outlet of the first heat exchanger 2 is connected to the inlet of the second heat exchanger 3, so that the second heat exchanger 3 heats the salt solution. The secondary side of the second heat exchanger 3 heats the salt solution from the energy tower. The outlet of the second heat exchanger 3 is connected to the inlet of the evaporator 5. The evaporator 5 dehumidifies and removes water, so that the solution is concentrated. Step (5): Once the salinity of the concentrated solution is reached, the control system issues a shutdown command, first shutting down the nanofiltration membrane device 9; Step (6): After confirming that the nanofiltration membrane equipment 9 is shut down, shut down the refrigeration circuit, first shut down the compressor, and then shut down the circulating fan 7. Step (7): Turn off solution circulation pump 10 in sequence; Step (8): Shut down the secondary water pump 11 for solution circulation; Step (9): Shut down vacuum pump 19.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump, characterized in that, This includes heat pump systems and nanofiltration membrane systems; among which, A heat pump system includes a refrigerant circuit, a solution circuit, a circulating air circuit, and a refrigeration and dehumidification circuit; among which, The refrigerant circuit includes a compressor (1), a first heat exchanger (2), a second heat exchanger (3), a throttle valve (4), and an evaporator (5), which are connected in sequence through transport pipelines to form a circuit; The solution loop includes a solution boiling regenerator (8), an energy tower (12), a first solution circulation secondary water pump (22), a second solution circulation secondary water pump (11), a hot solution circulation pump (10), and a second heat exchanger (3), which are connected in sequence through transport pipelines to form a loop. The first heat exchanger (2) is directly submerged in the solution boiling regenerator (8). The circulating air circuit includes a solution boiling regenerator (8) and a circulating fan (7), which are connected in a loop through a circulating air duct (16); The nanofiltration membrane system includes a solution circulation primary water pump (10), a nanofiltration membrane device (9), a high-pressure pump (20), a nanofiltration membrane (21), a solenoid valve (23), an ultrafilter (25), and a pressure reducing valve (26), which are connected in sequence to form a loop through transport pipelines.

2. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, The heat pump system also includes a vacuum maintenance loop to maintain the vacuum state of the gas loop and the solution boiling regenerator (8) and reduce the solution evaporation temperature.

3. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, The vacuum maintenance circuit includes a vacuum pump (19), a pressure regulating valve (17), and a pressure regulating tank (18). The gas from the solution boiling regenerator (8) is connected to the inlet of the pressure regulating valve (17), the outlet of the pressure regulating valve (17) is connected to the inlet of the pressure regulating tank (18), and the outlet of the pressure regulating tank (18) is connected to the inlet of the vacuum pump (19).

4. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, Both the first heat exchanger (2) and the second heat exchanger (3) are titanium tube shell-and-tube heat exchangers.

5. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, In the solution circuit, the outlet of the solution boiling regenerator (8) is connected to the inlet of the heating solution circulation pump (10). The outlet of the heating solution circulation pump (10) is divided into two circuits: one circuit is connected to the inlet of the solenoid valve (23), and the outlet of the solenoid valve (23) is connected in parallel with the concentrated solution outlet of the nanofiltration membrane device; the other circuit of the outlet of the heating solution circulation pump (10) is connected to the raw water inlet of the nanofiltration membrane device, and the concentrated solution outlet of the nanofiltration membrane device is connected in parallel with the outlet of the solenoid valve (23) and then connected to the inlet of the solution boiling regenerator (8).

6. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, In the nanofiltration membrane system, the outlet of the energy tower (12) is connected to the inlet of the second solution circulation secondary water pump (11), the outlet of the second solution circulation secondary water pump (11) is connected to the inlet of the second heat exchanger (3), and the outlet of the second heat exchanger (3) is connected to the other inlet X1 of the solution boiling regenerator (8). The other outlet X2 of the solution boiling regenerator (8) is connected to the inlet of the first solution circulation secondary water pump (22), and the outlet of the first solution circulation secondary water pump (22) is connected to the inlet of the energy tower (12).

7. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, In the circulating air circuit, the evaporator (5) is set in the circulating air duct (16). The gas in the solution boiling regenerator (8) is guided by the circulating fan (7) through the evaporator (5) and then flows back to the solution boiling regenerator (8).

8. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, It also includes a refrigeration dehumidification circuit, which includes an evaporator (5), a water tank (13), a normally open valve (14) and an electric valve (15), which are connected in sequence through a transport pipeline to form a circuit for refrigeration dehumidification and discharge of condensate. In the refrigeration dehumidification circuit, a normally open valve (14) is installed between the evaporator (5) and the water tank (13), and an electric valve (15) is connected to the outlet of the water tank (13). The electric valve (15) is used to discharge condensate.

9. The energy tower organic salt solution treatment system combining nanofiltration membrane and heat pump according to claim 1, characterized in that, In the refrigerant circuit, the outlet end of the compressor (1) discharges hot gas to the inlet end of the first heat exchanger (2), and the outside of the first heat exchanger (2) directly heats the salt solution; the outlet end of the first heat exchanger (2) is connected to the inlet end of the second heat exchanger (3), and the secondary side of the second heat exchanger (3) heats up the temperature of the salt solution from the energy tower; the outlet end of the second heat exchanger (3) is connected to the throttle valve (4), which is used to adjust the throttle flow rate of the refrigerant; the outlet of the throttle valve (4) is connected to the inlet end of the evaporator (5), which absorbs heat at low temperature and allows water vapor to condense into water; the outlet end of the evaporator (5) is connected to the liquid receiver (6), which is connected to the compressor (1) to complete one cycle.

10. A method for treating an organic salt solution, characterized in that, The energy tower organic salt solution treatment system using a nanofiltration membrane combined with a heat pump as described in any one of claims 1-9 specifically includes: Step (1): First, start the vacuum pump (19) and adjust the pressure regulating valve (17) to maintain the pressure regulating tank (18) at a vacuum of -5 Pa or higher; Step (2): Start the second solution circulation secondary water pump (11) so that the salt solution in the energy tower (12) flows through the second heat exchanger (3) for heat exchange, and then flows into the solution boiling regenerator (8). Step (3): Start the solution circulation pump (10) so that the liquid output of the solution boiling regenerator (8) flows into the nanofiltration membrane device through the solution circulation primary water pump (10) for ion and water separation. The concentrated solution after separation flows back into the solution boiling regenerator (8). The liquid output end X2 of the solution boiling regenerator (8) is connected to the inlet end of the solution circulation secondary water pump (22). The liquid output end of the solution circulation secondary water pump (22) is connected to the liquid output end of the energy tower (12) to form a solution loop circulation. Step (4): Start the refrigeration circuit. First, start the compressor (1). The outlet of the compressor (1) discharges hot gas to the first heat exchanger (2), so that the first heat exchanger (2) heats the salt solution. The outlet of the first heat exchanger (2) is connected to the inlet of the second heat exchanger (3), so that the second heat exchanger (3) heats the salt solution. The secondary side of the second heat exchanger (3) heats up the temperature of the salt solution from the energy tower. The outlet of the second heat exchanger (3) is connected to the inlet of the evaporator (5). The evaporator (5) dehumidifies and removes water, so that the solution is concentrated. Step (5): Once the salinity of the concentrated solution is reached, the control system issues a shutdown command, first shutting down the nanofiltration membrane equipment (9). Step (6): After confirming that the nanofiltration membrane equipment (9) is shut down, shut down the refrigeration circuit, first shut down the compressor, and then shut down the circulating fan (7). Step (7): Turn off the solution circulation pump (10) in sequence; Step (8): Shut down the secondary water pump for solution circulation (11); Step (9): Shut down the vacuum pump (19).

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