Low-energy-consumption evaporative crystallization system and process for treating salt-containing wastewater of power plant by utilizing heat pump technology

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a low-energy-consumption evaporative crystallization system and process for treating salt-containing wastewater of a power plant by using a heat pump technology, and the system comprises an evaporation tower, a heat exchanger, a condensing tower and a heat pump assembly; the external power plant salt-containing wastewater collecting tank is connected with the evaporation tower, a liquid outlet in the bottom of the evaporation tower is communicated with a first channel inlet of the heat exchanger, a first channel outlet of the heat exchanger is communicated with a backflow liquid inlet in the top of the evaporator, and the heat pump assembly is communicated with a second channel inlet of the heat exchanger. A second channel outlet of the heat exchanger communicates with the heat pump assembly, the heat exchanger provides a cold water source for the heat pump assembly, and the heat pump assembly supplies a generated high-temperature heat source to the heat exchanger; a water vapor outlet in the top of the evaporation tower is communicated with an inlet in the bottom end of the condensation tower. The low-temperature normal-pressure evaporation technology and the heat pump technology are combined, waste heat and waste heat are used for supplementing heat for the low-temperature normal-pressure evaporation technology, and low-energy-consumption operation of power plant salt-containing wastewater treatment is completed.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a low-energy consumption evaporation crystallization system and process for treating saline wastewater from power plants using heat pump technology. Background Art

[0002] Currently, most landfill leachate is recovered using membrane technology, and the membrane concentrate (salt, heavy metals, and difficult-to-degrade organic matter) is reinjected into the landfill. As time goes by, the water quality of the landfill leachate deteriorates dramatically, and the existing treatment processes are overwhelmed and have been partially shut down (biochemical and membrane processes).

[0003] Waste incineration power plants and coal-fired power plants contain a large amount of "waste heat" that needs to be cooled (turbine cooling water, generator cooling water, transformer cooling water, etc.) and high-temperature flue gas. In addition, various membrane processes need to treat concentrated water containing salt water. The current practice is to directly mix it with coal powder or dry garbage for incineration, causing furnace corrosion and the high salt content of the fuel affects the recovery and use of fly ash in the later stage. The existing evaporation process has a large demand for high-grade heat sources (industrial electricity, steam), but has not utilized low-grade heat sources and has not explored other uses, resulting in the waste of low-grade heat sources and no value. Low-grade heat sources also require resources to collect and cool down to meet production process requirements.

[0004] Therefore, it is crucial to utilize the above waste heat sources to optimize the saline wastewater treatment process in power plants. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a low-energy evaporation crystallization system and process for treating saline wastewater from power plants using heat pump technology.

[0006] The essence of the low-temperature evaporation technology of the evaporation tower in the present invention is to use the air temperature difference to affect the different water carrying capacity under normal pressure (the saturated vapor pressure of water vapor increases with the increase of temperature). The saturated vapor pressure of water vapor increases with the increase of temperature; the water vapor content in the air is very low under room temperature conditions, but when it is close to the boiling point of water (80°C) and above, the water vapor content in the air can be close to 75% to 90%. After heating, the salty wastewater of the power plant transfers the steam (humid air) in the evaporation tower to the condensation tower through wind, condenses and releases latent heat. The light components in the evaporation tower are continuously reduced, and the heavy components (salt, organic matter, heavy metals, etc.) are continuously accumulated to become concentrated mother liquor, and the final destination is incineration or crystallization; the sensible heat in the condensation tower is utilized, and reused after cooling by a cold source (cooling water, chilled water) or discharged after meeting the standards.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The first object of the present invention is to provide a low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology, which is connected to an external power plant saline wastewater collection tank and includes an evaporation tower, a heat exchanger, a condensation tower and a heat pump assembly;

[0009] The external power plant salt wastewater collection tank is connected to an evaporation tower, which is used to evaporate and concentrate the wastewater, thereby improving the wastewater recycling rate and reducing the wastewater terminal disposal rate;

[0010] The liquid outlet at the bottom of the evaporation tower is connected to the first channel inlet of the heat exchanger, so as to provide a cold water source for the heat exchanger;

[0011] The heat exchanger is used to convert a cold water source into a hot water source;

[0012] The first channel outlet of the heat exchanger is connected to the reflux liquid inlet at the top of the evaporator, and is used to provide a hot water source for the evaporator;

[0013] The heat pump assembly is connected to the second channel inlet of the heat exchanger, the second channel outlet of the heat exchanger is connected to the heat pump assembly, the heat exchanger is used to provide a cold water source for the heat pump assembly, and the heat pump assembly is used to receive the low-temperature heat source of the heat exchanger and convert it into a high-temperature heat source to power the heat exchanger;

[0014] The water vapor outlet at the top of the evaporation tower is connected to the inlet at the bottom of the condensation tower, and the condensation tower is used to condense the water vapor in the evaporation tower into recyclable water.

[0015] In the present invention, the evaporation tower adopts low-temperature positive pressure evaporation technology.

[0016] In one embodiment of the present invention, the heat pump assembly is connected to an external cooling circulation tower, which is used to provide an external waste heat source for the heat pump assembly and receive the low-temperature refrigerant of the heat pump assembly.

[0017] In one embodiment of the present invention, the heat pump assembly comprises an evaporator, a compressor and a condenser;

[0018] The first channel outlet of the evaporator is connected to the inlet of the compressor, the outlet of the compressor is connected to the first channel inlet of the condenser, and the first channel outlet of the condenser is connected to the first channel inlet of the evaporator and the liquid inlet of the external cooling circulation tower;

[0019] The second channel outlet of the heat exchanger is connected to the first channel inlet of the evaporator, and the gas outlet of the condenser is connected to the second channel inlet of the heat exchanger;

[0020] The gas outlet of the external cooling circulation tower is connected to the gas inlet of the evaporator;

[0021] The evaporator is used to receive the cold water source of the heat exchanger and the waste heat source of the external cooling circulation tower, absorb the waste heat source and convert the cold water source into low-temperature and low-pressure gas;

[0022] The compressor is used to convert low-temperature and low-pressure gas into high-temperature and high-pressure gas;

[0023] The condenser is used to convert high-temperature and high-pressure gas into low-temperature refrigerant and release high-temperature heat source; the condenser is connected to the heat exchanger to provide a high-temperature heat source for the heat exchanger and provide low-temperature refrigerant for the evaporator and the external cooling circulation tower.

[0024] In one embodiment of the present invention, the bottom liquid outlet of the condensation tower is connected to the top inlet of the condensation tower through a reflux pipe to improve the condensation effect of the condensation tower.

[0025] In one embodiment of the present invention, the bottom liquid outlet of the condensation tower is connected to an external reclaimed water reuse system through a liquid pipeline.

[0026] In one embodiment of the present invention, a condensation circulation water pump is provided at the bottom liquid outlet of the condensation tower.

[0027] In one embodiment of the present invention, a forced circulation water pump is provided at the bottom liquid outlet of the evaporation tower.

[0028] In one embodiment of the present invention, the evaporation tower is connected to a blower, and the blower is used to provide a stable airflow for the evaporation tower to improve the evaporation efficiency of the evaporation tower.

[0029] In one embodiment of the present invention, a liquid inlet pump is provided at the bottom liquid inlet of the evaporation tower.

[0030] In one embodiment of the present invention, a waste residue discharge valve is provided at the bottom liquid outlet of the evaporation tower.

[0031] The second object of the present invention is to provide a low-energy evaporation and crystallization process for treating saline wastewater from power plants using heat pump technology, using the above system, comprising the following steps:

[0032] The salty wastewater collection tank of the external power plant transports the wastewater to the evaporation tower through the liquid inlet pump. The evaporation tower evaporates and concentrates the wastewater, and the evaporated water vapor is obtained at the top and the concentrated wastewater is obtained at the bottom.

[0033] The evaporated water vapor enters the condensation tower through the top water vapor outlet, and the condensation tower condenses the evaporated water vapor into recyclable water;

[0034] The concentrated wastewater is transported to the heat exchanger through a forced circulation water pump. The heat exchanger heats the concentrated wastewater and returns the heated concentrated wastewater to the top of the evaporation tower. A part of the cold water source in the heat exchanger is transported to the heat pump component, which converts the cold water source into a high-temperature heat source and transports it to the heat exchanger.

[0035] In one embodiment of the present invention, the evaporator absorbs the waste heat source provided by the external cooling circulation tower to convert the cold water source into low-temperature and low-pressure gas, and transmits it to the compressor.

[0036] The compressor compresses the low-temperature and low-pressure gas into high-temperature and high-pressure gas and delivers it to the condenser;

[0037] The condenser converts high-temperature and high-pressure gas into low-temperature refrigerant and releases high-temperature heat source. The high-temperature heat source is transported to the heat exchanger, and the low-temperature refrigerant is transported to the evaporator and the external cooling cycle tower.

[0038] In one embodiment of the present invention, the circulating water of the condensation tower is refluxed to the condensation tower through a reflux pipe for condensation treatment;

[0039] The recyclable water obtained from the condensation tower is as follows:

[0040] If the recyclable water meets the discharge standard, it will be discharged directly through the recyclable water discharge valve;

[0041] If the recyclable water meets the reuse standards, it will enter the reclaimed water reuse system through the reuse water discharge valve;

[0042] If the recyclable water does not meet the discharge standards, it will enter the wastewater treatment system again through the recyclable water discharge valve.

[0043] In one embodiment of the present invention, if the concentrated wastewater is concentrated 8 to 10 times to salt saturation, it can be discharged through the waste residue discharge valve.

[0044] In one embodiment of the present invention, the external cooling circulation tower delivers the waste heat source it generates to the evaporator;

[0045] A portion of the low-temperature refrigerant produced by the condenser is sent to the external circulation tower.

[0046] In one embodiment of the present invention, the blower delivers the cold air generated by it to the evaporation tower.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The system provided by the present invention introduces an evaporation process to complete the terminal disposal of desalted water in power plant boilers and membrane concentrate in landfills. It can complete evaporation and concentration at normal pressure until the crystallized salt begins to crystallize, eliminating the continuous deterioration of water quality caused by disorderly discharge of desalted water and reinjection of landfill leachate (membrane concentrate). The wastewater fundamentally removes difficult-to-degrade organic matter, salt, heavy metals, etc. from the system, and the produced water can be directly reused as boiler inlet water or directly used as circulating water to supplement the cooling circulation system. It is very friendly to the stable operation of the wastewater system and also reduces the large amount of heat source waste caused by the incineration of concentrated liquid.

[0049] (2) The system provided by the present invention adopts a normal pressure and low temperature evaporation process, which is safe and reliable in daily production, has no dangerous control points, and is relatively friendly to production safety and personnel operation; and uses air as a power source to continuously drive the evaporated secondary steam, and the humid air can be repeatedly recycled after condensation.

[0050] (3) The system provided by the present invention is not affected by changes in water quality (salt type, high-boiling organic matter, low-boiling organic matter content) in terms of treatment efficiency and treatment effect. The produced water can be directly reused due to its mild evaporation effect and excellent water quality.

[0051] (4) The system provided by the present invention uses a low-temperature evaporation process, taking into account the waste heat source, which is mainly the exhaust steam from waste incineration power generation and coal-fired power generation, turbine cooling water, etc. (all of which are relatively low-grade heat sources), and converts them into high-temperature heat sources through a heat pump component and provides them to a heat exchanger.

[0052] (5) Considering that the COP value is the largest in the optimal operating state of the heat pump, the temperature gradient is large, the energy level span is large, the greater the input power, the lower the energy efficiency ratio, and for the evaporator heat exchange, in principle, as long as the heat source is greater than the set evaporation temperature, heat exchange can be carried out. However, if the logarithmic temperature difference is small, the heat exchanger area is large (precious metals are used for the heat exchanger), and the equipment is not economical.

[0053] (6) In the system provided by the present invention, the heat pump component outputs a hot water source temperature of 45°C to 85°C, which is particularly suitable for low-temperature evaporation processes. Due to the low-temperature evaporation temperature (55 to 100°C), the heat pump component and the low-temperature evaporation process are used to complement each other, and the waste heat and residual heat generated by the power plant are used to "treat waste with waste", which also promotes the green and sustainable development of the power plant.

[0054] (7) The heat pump assembly in the system provided by the present invention refers to a heat pump unit that can recover 20-55°C and provide hot water at 65-95°C, and uses a compressor to continuously extract energy from a low-temperature heat source to supply a condenser.

[0055] In general, the present invention adopts a combination of low-temperature atmospheric pressure evaporation technology and heat pump technology, and uses "waste heat and residual heat" to supplement the heat of the low-temperature atmospheric pressure evaporation technology, completes the low-energy consumption operation of the power plant's saline wastewater treatment, and promotes the green and sustainable development of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A schematic diagram of a low-energy evaporation and crystallization system for treating saline wastewater from a power plant using heat pump technology according to the present invention;

[0057] Numbers in the figure: 1. Blower; 2. Salt wastewater collection tank of power plant; 3. Evaporation tower; 4. Forced circulation water pump; 5. Waste residue discharge valve; 6. Heat exchanger; 7. Condensation tower; 8. Condensation circulation water pump; 9. Recycled water discharge valve; 10. Evaporator; 11. Compressor; 12. Condenser; 13. Cooling circulation tower; 14. Waste heat source supplementary pump; 15. Liquid inlet pump. DETAILED DESCRIPTION

[0058] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0061] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0062] In the following embodiments, unless otherwise specified, the structures or components used are conventional structures or components in the art, as long as they can achieve the corresponding functions.

[0063] Example 1

[0064] This embodiment provides a low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology. Figure 1 As shown, it is connected to the external power plant salt wastewater collection tank 2, including an evaporation tower 3, a heat exchanger 6, a condensation tower 7 and a heat pump component; the external power plant salt wastewater collection tank 2 is connected to the evaporation tower 3, and the evaporation tower 3 is used to evaporate and concentrate the wastewater, improve the wastewater recycling rate, and reduce the wastewater terminal disposal rate; the liquid outlet at the bottom of the evaporation tower 3 is connected to the first channel inlet of the heat exchanger 6, which is used to provide a cold water source for the heat exchanger 6; the heat exchanger 6 is used to convert the cold water source into a hot water source; the first channel outlet of the heat exchanger 6 is connected to the evaporation tower 3. The top reflux liquid inlet of the evaporator 10 is connected to provide a hot water source for the evaporator 10; the heat pump component is connected to the second channel inlet of the heat exchanger 6, and the second channel outlet of the heat exchanger 6 is connected to the heat pump component. The heat exchanger 6 is used to provide a cold water source for the heat pump component. The heat pump component is used to receive the low-temperature heat source of the heat exchanger 6 and convert it into a high-temperature heat source to power the heat exchanger 6; the water vapor outlet at the top of the evaporation tower 3 is connected to the bottom inlet of the condensation tower 7, and the condensation tower 7 is used to condense the water vapor of the evaporation tower 3 into recyclable water.

[0065] Furthermore, the heat pump assembly is connected to an external cooling circulation tower 13, and the external cooling circulation tower 13 is used to provide an external waste heat source for the heat pump assembly and receive the low-temperature refrigerant of the heat pump assembly.

[0066] Furthermore, the heat pump assembly includes an evaporator 10, a compressor 11 and a condenser 12; the first channel outlet of the evaporator 10 is connected to the inlet of the compressor 11, the outlet of the compressor 11 is connected to the first channel inlet of the condenser 12, the first channel outlet of the condenser 12 is connected to the first channel inlet of the evaporator 10 and the liquid inlet of the external cooling circulation tower 13; the second channel outlet of the heat exchanger 6 is connected to the first channel inlet of the evaporator 10, the gas outlet of the condenser 12 is connected to the second channel inlet of the heat exchanger 6; the gas outlet of the external cooling circulation tower 13 is connected to the gas outlet of the evaporator 10 The inlet is connected; the evaporator 10 is used to receive the cold water source of the heat exchanger 6 and the waste heat source of the external cooling circulation tower 13, absorb the waste heat source and convert the cold water source into a low-temperature and low-pressure gas; the compressor 11 is used to convert the low-temperature and low-pressure gas into a high-temperature and high-pressure gas; the condenser 12 is used to convert the high-temperature and high-pressure gas into a low-temperature refrigerant and release a high-temperature heat source; the condenser 12 is connected to the heat exchanger 6 through a waste heat source delivery pipeline to provide a high-temperature heat source for the heat exchanger 6, and provide a low-temperature refrigerant for the evaporator 10 and the external cooling circulation tower 13; a waste heat source supply pump 14 is provided on the waste heat source delivery pipeline.

[0067] Furthermore, the bottom liquid outlet of the condensation tower 7 is connected to the top inlet of the condensation tower 7 through a reflux pipe, so as to improve the condensation effect of the condensation tower 7.

[0068] The reflux pipeline is provided with a condensation circulation water pump 8, the reflux pipeline is allowed to be connected to a discharge pipeline, and a recycled water discharge valve 9 is provided on the discharge pipeline;

[0069] Furthermore, the bottom liquid outlet of the evaporation tower 3 is connected to the first channel inlet of the heat exchanger 6 through a liquid pipeline, and a forced circulation water pump 4 is provided on the liquid pipeline. The liquid pipeline is allowed to be connected to a discharge pipeline, and a waste residue discharge valve 5 is provided on the discharge pipeline.

[0070] Furthermore, the blower 1 is connected to the evaporation tower 3 through a gas pipeline, and the blower 1 is used to provide a stable airflow for the evaporation tower 3 to improve the evaporation efficiency of the evaporation tower 3.

[0071] Furthermore, the saline wastewater from the power plant is connected to the evaporation tower 3 via a liquid inlet pipeline, and a liquid inlet pump 15 is provided on the liquid inlet pipeline.

[0072] Example 2

[0073] This embodiment provides a low-energy evaporation and crystallization process for treating saline wastewater from a power plant using heat pump technology. The low-energy evaporation and crystallization system for treating saline wastewater from a power plant using heat pump technology in Example 1 includes the following steps:

[0074] The external power plant salt wastewater collection tank 2 transports the wastewater to the evaporation tower 3 through the liquid inlet pump 15. The evaporation tower 3 evaporates and concentrates the wastewater, obtains evaporated water vapor at the top, and obtains concentrated wastewater at the bottom (during the operation of the evaporation tower 3, the blower 1 transports cold air to the evaporation tower 3 through the gas pipeline);

[0075] The evaporated water vapor enters the condensation tower 7 through the top water vapor outlet, and the condensation tower 7 condenses the evaporated water vapor into recyclable water; the circulating water of the condensation tower 7 flows back to the condensation tower 7 through the reflux pipe for condensation treatment;

[0076] The recyclable water obtained by the condensation tower is specifically as follows: if the recyclable water meets the discharge standard, it will be directly discharged through the reuse water discharge valve 9; if the recyclable water meets the reuse standard, it will enter the reclaimed water reuse system through the reuse water discharge valve 9; if the recyclable water does not meet the discharge standard, it will enter the wastewater treatment system again through the reuse water discharge valve 9.

[0077] The concentrated wastewater is transported to the heat exchanger 6 through the forced circulation water pump 4, and the heat exchanger 6 heats the concentrated wastewater and returns the heated concentrated wastewater to the top of the evaporation tower 3;

[0078] A portion of the cold water source in the heat exchanger 6 is transported to the evaporator 10. The cold water circulation tower uses the waste heat source supplementary pump 14 to transport the generated waste heat source to the evaporator 10. The evaporator 10 absorbs the external waste heat source to convert the cold water source into a low-temperature low-pressure gas, and transports it to the compressor 11. The compressor 11 compresses the low-temperature low-pressure gas into a high-temperature high-pressure gas and transports it to the condenser 12; the condenser 12 converts the high-temperature high-pressure gas into a low-temperature refrigerant and releases a high-temperature heat source. The high-temperature heat source is transported to the heat exchanger 6, and the low-temperature refrigerant is transported to the evaporator 10 and the external cooling circulation tower 13;

[0079] If the concentrated wastewater is concentrated 8 to 10 times to salt saturation, the waste discharge valve 5 is opened and discharged.

[0080] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A low-energy evaporation and crystallization system for treating saline wastewater from a power plant using heat pump technology, connected to an external saline wastewater collection tank (2) of a power plant, characterized in that: It comprises an evaporation tower (3), a heat exchanger (6), a condensation tower (7) and a heat pump assembly; The external power plant salt wastewater collection tank (2) is connected to an evaporation tower (3), and the evaporation tower (3) is used to evaporate and concentrate the wastewater; The liquid outlet at the bottom of the evaporation tower (3) is connected to the first channel inlet of the heat exchanger (6) to provide a cold water source for the heat exchanger (6); The heat exchanger (6) is used to convert a cold water source into a hot water source; The first channel outlet of the heat exchanger (6) is connected to the reflux liquid inlet at the top of the evaporator (10) to provide a hot water source for the evaporator (10); The heat pump assembly is connected to the second channel inlet of the heat exchanger (6), the second channel outlet of the heat exchanger (6) is connected to the heat pump assembly, the heat exchanger (6) is used to provide a cold water source for the heat pump assembly, and the heat pump assembly is used to receive the low-temperature heat source of the heat exchanger (6) and convert it into a high-temperature heat source to supply energy to the heat exchanger (6); The water vapor outlet at the top of the evaporation tower (3) is connected to the inlet at the bottom of the condensation tower (7), and the condensation tower (7) is used to condense the water vapor in the evaporation tower (3) into recyclable water.

2. A low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology according to claim 1, characterized in that: The heat pump component is connected to an external cooling circulation tower (13), and the external cooling circulation tower (13) is used to provide an external waste heat source for the heat pump component and receive the low-temperature refrigerant of the heat pump component.

3. A low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology according to claim 2, characterized in that: The heat pump assembly comprises an evaporator (10), a compressor (11) and a condenser (12); The first channel outlet of the evaporator (10) is connected to the inlet of the compressor (11), the outlet of the compressor (11) is connected to the first channel inlet of the condenser (12), and the first channel outlet of the condenser (12) is connected to the first channel inlet of the evaporator (10) and the liquid inlet of the external cooling circulation tower (13); The second channel outlet of the heat exchanger (6) is connected to the first channel inlet of the evaporator (10), and the gas outlet of the condenser (12) is connected to the second channel inlet of the heat exchanger (6); The gas outlet of the external cooling circulation tower (13) is connected to the gas inlet of the evaporator (10); The evaporator (10) is used to receive the cold water source of the heat exchanger (6) and the waste heat source of the external cooling circulation tower (13), absorb the waste heat source and convert the cold water source into low-temperature and low-pressure gas; The compressor (11) is used to convert low-temperature and low-pressure gas into high-temperature and high-pressure gas; The condenser (12) is used to convert high-temperature and high-pressure gas into low-temperature refrigerant and release high-temperature heat source; the condenser (12) is connected to the heat exchanger (6) to provide a high-temperature heat source for the heat exchanger (6) and to provide low-temperature refrigerant for the evaporator (10) and the external cooling circulation tower (13).

4. The low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology according to claim 1, characterized in that: The bottom liquid outlet of the condensation tower (7) is connected to the top reflux liquid inlet of the condensation tower (7) or an external reclaimed water recycling system.

5. The low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology according to claim 1, characterized in that: The evaporation tower (3) is connected to the blower (1) via a gas delivery pipeline, and the blower (1) is used to provide a stable airflow for the evaporation tower (3) to improve the evaporation efficiency of the evaporation tower (3).

6. The low-energy evaporation and crystallization system for treating saline wastewater from power plants using heat pump technology according to claim 1, characterized in that: A waste residue discharge valve (5) is provided at the bottom liquid outlet of the evaporation tower (3).

7. A low-energy evaporation crystallization process for treating saline wastewater from power plants using heat pump technology, characterized in that: Using the system according to any one of claims 1 to 6 comprises the following steps: The external power plant salt wastewater collection tank (2) transports the wastewater to the evaporation tower (3) through the liquid inlet pump (15). The evaporation tower (3) evaporates and concentrates the wastewater, obtains evaporated water vapor at the top, and obtains concentrated wastewater at the bottom; The evaporated water vapor enters the condensation tower (7) through the top water vapor outlet, and the condensation tower (7) condenses the evaporated water vapor into recyclable water; The concentrated wastewater is transported to the heat exchanger (6) through a forced circulation water pump (4), the heat exchanger (6) heats the concentrated wastewater and returns the heated concentrated wastewater to the top of the evaporation tower (3); a portion of the cold water source in the heat exchanger (6) is transported to the heat pump assembly, and the heat pump assembly converts the cold water source into a high-temperature heat source and transports it to the heat exchanger (6).

8. The low-energy evaporation and crystallization process for treating saline wastewater from power plants using heat pump technology according to claim 7, characterized in that: The evaporator (10) absorbs the waste heat source provided by the external cooling circulation tower (13) to convert the cold water source into low-temperature and low-pressure gas, and transmits it to the compressor (11); The compressor (11) compresses the low-temperature and low-pressure gas into high-temperature and high-pressure gas and transmits the gas to the condenser (12); The condenser (12) converts the high-temperature and high-pressure gas into a low-temperature refrigerant and releases a high-temperature heat source, the high-temperature heat source is transported to the heat exchanger (6), and the low-temperature refrigerant is transported to the evaporator (10) and the external cooling circulation tower (13).

9. The low-energy evaporation and crystallization process for treating saline wastewater from power plants using heat pump technology according to claim 7, characterized in that: If the concentrated wastewater is concentrated 8 to 10 times to salt saturation, it is allowed to be discharged through the waste discharge valve (5).

10. The low-energy evaporation and crystallization process for treating saline wastewater from power plants using heat pump technology according to claim 7, characterized in that: The blower (1) delivers the cold air generated by it to the evaporation tower (3).

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