Low-temperature heat pump evaporator

Abstract

The low-temperature heat pump evaporator comprises a separator, a forced circulation pump, a heat pump unit, a condenser, a refrigerant storage tank and a refrigeration circulation pump, the heat pump unit is provided with a refrigeration inlet, a refrigeration outlet, a heating inlet and a heating outlet, and the condenser is provided with a steam inlet, a condensation outlet, a refrigerant inlet and a refrigerant outlet; the conveying pump is used for conveying the feed liquid into the separator and conveying the concentrated crystal mush to the solid-liquid separation assembly for solid-liquid separation; the condensate water tank is communicated with the condensate outlet, and the condensate water tank is provided with a negative pressure opening communicated with the vacuum pump and a water pumping opening communicated with the condensate water pump. According to the low-temperature heat pump evaporator, feed liquid is driven by the forced circulation pump to circulate and pass through the separator and the heat pump unit, and the feed liquid before concentration and crystal mush after concentration are conveyed by utilizing the discharge pump, so that the use number of pump bodies is reduced, the pipeline structure is simplified, and the cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of evaporation and concentration technology, and in particular to a low-temperature heat pump evaporator. Background Technology

[0002] Evaporation concentration is a common and important method for treating industrial wastewater, especially in the reduction and resource recovery of high-salt, high-concentration, and recalcitrant wastewater. Its core principle is to vaporize and separate water and other solvents in the wastewater through heating, thereby concentrating and reducing pollutants while simultaneously recovering clean water or solvents.

[0003] Evaporation and concentration processes require heating or drying, and the temperature of the heating medium during evaporation and concentration is generally above 150°C. Even with MVR technology, the temperature of the discharged heating medium is still above 70°C, and the discharged heating medium cannot be recycled. To address this, Chinese utility model patent CN220801965U discloses a low-temperature vacuum evaporation and drying system. This system uses a vacuum pump to reduce the pressure inside the vacuum evaporation tank, thereby lowering the boiling point of the waste liquid. The heat pump discharges heats the concentrated liquid to be treated, and the cold water produced by the heat pump unit is used as cooling water to condense the vapor from the evaporated concentrated liquid, forming a closed-loop low-temperature evaporation system that reduces heat loss and emissions, thus achieving energy saving.

[0004] However, the aforementioned low-temperature evaporation system requires the use of multiple pumps, such as a concentrate pump, a separator pump, an evaporator circulation pump, a high-temperature water pump, a heat source water pump, and a vacuum pump. This makes the piping system of the low-temperature evaporation device complex and increases costs. Furthermore, the concentration of the liquid relies entirely on the heat generated by the heat pump unit, resulting in low concentration efficiency. Moreover, after long-term operation of multiple pumps, their temperatures gradually rise, and continuous operation at high temperatures will shorten the service life of these pumps.

[0005] Therefore, it is necessary to improve the existing low-temperature heat pump evaporation devices. Utility Model Content

[0006] The purpose of this invention is to overcome the defects in the existing technology and provide a low-temperature heat pump evaporator that reduces the number of pump bodies to simplify the structure, reduce costs, extend the service life of the pump bodies, and improve the evaporation and concentration efficiency.

[0007] To achieve the above-mentioned technical effects, the technical solution of this utility model is: a low-temperature heat pump evaporator, comprising:

[0008] The system includes a separator, a forced circulation pump, a heat pump unit, a condenser, a refrigerant storage tank, and a refrigeration circulation pump. The heat pump unit has a refrigeration inlet, a refrigeration outlet, a heating inlet, and a heating outlet. The condenser has a steam inlet, a condensation outlet, a refrigerant inlet, and a refrigerant outlet. The separator, the forced circulation pump, the heating inlet, and the heating outlet are connected sequentially. The refrigerant storage tank, the refrigeration circulation pump, the refrigeration inlet, the refrigeration outlet, the refrigerant inlet, and the refrigerant outlet are also connected sequentially.

[0009] A delivery pump and a solid-liquid separation assembly, wherein the delivery pump is used to input the liquid feed into the separator and to deliver the concentrated crystal slurry to the solid-liquid separation assembly for solid-liquid separation;

[0010] A vacuum pump, a condensate tank, and a condensate pump are provided. The condensate tank is connected to the condensate outlet and has a negative pressure port connected to the vacuum pump and a water inlet connected to the condensate pump.

[0011] Preferably, in order to improve the evaporation and concentration efficiency, a preheater is also included. The preheater has a preheating inlet, a preheating outlet, a heat medium inlet, and a heat medium outlet. The heat medium inlet is used to connect to a heat source. The preheating outlet is connected to the separator. The preheating inlet is connected to the output end of the delivery pump.

[0012] Preferably, in order to further improve the evaporation and concentration efficiency, the heat source is an electrically heated steam generator.

[0013] Preferably, in order to make full use of the heat source and reduce heat loss, the heat medium outlet is connected to a steam trap.

[0014] Preferably, for ease of drainage, the heat medium outlet is connected to the electrically heated steam generator.

[0015] Preferably, in order to ensure the normal and stable use of the vacuum pump and extend its service life, the vacuum pump also has a vacuum cooling inlet and a vacuum cooling outlet, wherein the vacuum cooling inlet and the vacuum cooling outlet are sequentially connected between the refrigeration outlet and the refrigerant inlet.

[0016] Preferably, in order to ensure the normal and stable use of the forced circulation pump and the delivery pump and extend their service life, the forced circulation pump has a circulating cooling inlet and a circulating cooling outlet, and the delivery pump has a delivery cooling inlet and a delivery cooling outlet. The circulating cooling inlet and the delivery cooling inlet are both connected to the input end of the refrigeration circulation pump, and the circulating cooling outlet and the delivery cooling outlet are both connected to the refrigerant storage tank.

[0017] Preferably, in order to achieve solid-liquid separation, the solid-liquid separation component includes a thickener, a centrifuge, and a mother liquor tank. The thickener has a thickening inlet, an overflow outlet, and a thickening outlet. The centrifuge has a centrifugal inlet, a centrifugal drain outlet, and a centrifugal crystal discharge outlet. The thickening inlet is connected to one of the output ends of the delivery pump. The overflow outlet and the centrifugal drain outlet are both connected to the mother liquor tank. The centrifugal crystal discharge outlet is used to connect to the crystallization and packaging system.

[0018] Preferably, in order to improve separation efficiency and reduce material waste, the mother liquor tank is connected to the input end of the forced circulation pump.

[0019] Preferably, in order to facilitate sedimentation and improve the solid-liquid separation effect, the thickener also has a cooling inlet and a cooling outlet, the cooling inlet and the cooling outlet being used for inputting and outputting coolant, respectively.

[0020] In summary, compared with the prior art, the low-temperature heat pump evaporator of this utility model uses a forced circulation pump to drive the liquid to circulate through the separator and heat pump unit, and uses a discharge pump to realize the transfer of the liquid before concentration and the crystal slurry after concentration, thereby reducing the number of pumps used, simplifying the pipeline structure and reducing costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the first embodiment;

[0022] Figure 2 This is a schematic diagram of the relevant structure of the first embodiment for processing liquid feed;

[0023] Figure 3 This is a schematic diagram of the relevant structure for steam processing in the first embodiment;

[0024] Figure 4 This is a schematic diagram of the relevant structure for processing refrigerant in the first embodiment;

[0025] In the diagram: 1. Separator; 101. Inlet; 102. Outlet; 103. Steam Outlet; 104. Circulation Outlet; 105. Circulation Inlet; 2. Forced Circulation Pump; 201. Circulation Cooling Inlet; 202. Circulation Cooling Outlet; 3. Heat Pump Unit; 301. Refrigeration Inlet; 302. Refrigeration Outlet; 303. Heating Inlet; 304. Heating Outlet; 4. Condenser; 401. Steam Inlet; 402. Condensation Outlet; 403. Refrigerant Inlet; 404. Refrigerant Outlet; 5. Refrigerant Storage Tank; 6. Refrigeration Circulation Pump; 7. Transfer Pump; 701. Transfer Cooling Inlet; 702. Transfer Cooling Outlet; 8. Vacuum Pump; 801. 802. Vacuum cooling inlet; 9. Vacuum cooling outlet; 10. Condensate tank; 11. Negative pressure port; 12. Water extraction port; 13. Water inlet; 14. Condensate pump; 15. Preheater; 16. Preheating inlet; 17. Preheating outlet; 18. Heat medium inlet; 19. Heat medium outlet; 10. Steam trap; 10. Heat source; 11. Thickener; 12. Thickener inlet; 13. Overflow port; 14. Thickener outlet; 15. Cooling inlet; 16. Cooling outlet; 17. Centrifuge; 18. Centrifuge inlet; 19. Centrifuge drain port; 10. Centrifuge crystal discharge port; 11. Mother liquor tank. Detailed Implementation

[0026] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0027] First Embodiment

[0028] like Figures 1-4 As shown, a low-temperature heat pump evaporator according to the first embodiment of this utility model includes:

[0029] The system comprises a separator 1, a forced circulation pump 2, a heat pump unit 3, a condenser 4, a refrigerant storage tank 5, and a refrigeration circulation pump 6. The heat pump unit 3 has a refrigeration inlet 301, a refrigeration outlet 302, a heating inlet 303, and a heating outlet 304. The condenser 4 has a steam inlet 401, a condensation outlet 402, a refrigerant inlet 403, and a refrigerant outlet 404. The separator 1, the forced circulation pump 2, the heating inlet 303, and the heating outlet 304 are connected end to end. The refrigerant storage tank 5, the refrigeration circulation pump 6, the refrigeration inlet 301, the refrigeration outlet 302, the refrigerant inlet 403, and the refrigerant outlet 404 are also connected end to end.

[0030] The transfer pump 7 is used to input the liquid into the separator 1 and to transport the concentrated crystal slurry to the solid-liquid separation component for solid-liquid separation.

[0031] The system includes a vacuum pump 8, a condensate tank 9, and a condensate pump 10. The condensate tank 9 is connected to a condensate outlet 402. The condensate tank 9 has a negative pressure port 901 connected to the vacuum pump 8 and a water extraction port 902 connected to the condensate pump 10.

[0032] When the low-temperature heat pump evaporator is running, the liquid to be concentrated is transported to the separator 1 by the transfer pump 7. The concentrated liquid is circulated between the separator 1 and the heating inlet 303 and heating outlet 304 of the heat pump unit 3 by the forced circulation pump 2, so that the concentration of the liquid gradually decreases and forms a slurry. Then, it is transported to the solid-liquid separation component by the transfer pump 7. The solid-liquid separation component performs solid-liquid separation to obtain the concentrated liquid. During the evaporation and concentration process, the secondary steam generated is heat-exchanged by the refrigerant generated by the heat pump unit 3. The secondary steam is condensed into water and transported into the condensate tank 9. The non-condensable gas in the condensate tank 9 is removed by the vacuum pump 8, and a negative pressure is formed inside the separator 1, which effectively reduces the evaporation temperature and is conducive to the evaporation and concentration of the liquid inside the separator 1. After exchanging heat with the secondary steam, the refrigerant returns to the refrigerant storage tank 5 and is transported by the refrigeration circulation pump 6 through the refrigeration inlet 301 and refrigeration outlet 302 of the heat pump unit 3, thereby realizing the recycling of the refrigerant.

[0033] Therefore, the low-temperature heat pump evaporator concentrator of this embodiment retains the low-temperature vacuum evaporation and concentration of the feed liquid to reduce the concentration power consumption. At the same time, it uses the heat energy generated by the heat pump unit 3 to heat the feed liquid and cool the refrigerant to facilitate the condensation and cooling of the secondary steam to form condensate. The feed liquid can be transported by only the forced circulation pump 2 and the transfer pump 7, which reduces the number of pumps. This helps to reduce the piping structure of the entire evaporation and concentration system and thus reduce the cost.

[0034] A further improvement is that it also includes a preheater 11, which has a preheating inlet 1101, a preheating outlet 1102, a heat medium inlet 1103 and a heat medium outlet 1104. The heat medium inlet 1103 is used to connect to the heat source 12, the preheating outlet 1102 is connected to the separator 1, and the preheating inlet 1101 is connected to the output end of the transfer pump 7.

[0035] By setting up a preheater 11, when the delivery pump 7 delivers the liquid to the separator 1, the liquid is first fed into the preheater 11. The heat generated by the heat source 12 passes through the heat medium inlet 1103 and the heat medium outlet 1104 in sequence, and then is discharged from the system. The heat flow and the liquid exchange heat when passing through the preheater 11, which raises the temperature of the liquid. This reduces the burden of the heat pump unit 3 on heating the liquid and helps the liquid to heat up quickly, thereby improving the heating, evaporation and concentration efficiency.

[0036] A further improvement is that the heat source 12 is an electrically heated steam generator.

[0037] An electric heating steam generator is a key piece of equipment that converts electrical energy into heat energy, uses soft water as the main raw material to generate steam, and provides a heat source 12 for the evaporation process. Compared with other coal / gas-fired boilers or other steam sources, it can provide a stable heat input to the evaporator, promoting the evaporation and concentration process of the feed liquid. The generated steam is transported through pipelines to the preheater 11, where it exchanges heat with the feed liquid, releases latent heat, and condenses into water. The condensed water is discharged through the heat medium outlet 1104, or it can be recycled back into the electric heating steam generator for reuse. In addition, compared with traditional steam generators, electric heating steam generators do not burn during operation and do not produce exhaust gas, meeting environmental protection requirements. They can generate steam quickly after being powered on, which is faster than traditional boilers, and allows for more precise adjustment of steam temperature and pressure. Moreover, electric heating steam generators typically adopt a modular design, occupy a small area, and do not require complex chimneys and fuel storage systems.

[0038] A further improvement is that a steam trap 1105 is connected to the heat medium outlet 1104. By setting the steam trap 1105, it is convenient to control the discharge of steam heat medium, so as to regulate the flow rate and pressure of the heat medium in the preheater 11, so that it can fully contact the liquid material, thereby making full use of the heat of steam, reducing heat loss, and achieving energy saving.

[0039] A further improvement is that the solid-liquid separation assembly includes a thickener 13, a centrifuge 14, and a mother liquor tank 15. The thickener 13 has a thickening inlet 1301, an overflow port 1302, and a thickening outlet 1303. The centrifuge 14 has a centrifugal inlet 1401, a centrifugal drain port 1402, and a centrifugal crystal discharge port 1403. The thickening inlet 1301 is connected to one of the output ends of the transfer pump 7. The overflow port 1302 and the centrifugal drain port 1402 are both connected to the mother liquor tank 15. The centrifugal crystal discharge port 1403 is used to connect to the crystallization and dispensing system. The mother liquor tank 15 is connected to the input end of the forced circulation pump 2.

[0040] Specifically, the thickening inlet 1301, overflow port 1302, and thickening outlet 1303 are located at the top, upper sidewall, and bottom of the thickener 13, respectively. The centrifugal inlet 1401 is located at the top of the centrifuge 14, and the centrifugal drain port 1402 and centrifugal crystal discharge port 1403 are located at the bottom ends of the centrifuge 14. With the above design, the slurry formed after the evaporation and concentration of the liquid is pumped by the transfer pump 7 to the thickener 13 through the thickening inlet 1301. The thickener 13 performs sedimentation treatment, causing the denser crystal particles to fall to the bottom and the less dense liquid to float to the top. The liquid is discharged from the overflow port 1302 and enters the mother liquor tank 15. The crystals and mother liquor at the bottom are discharged through the thickening outlet 1303 and centrifuged through the centrifugal inlet 1401 to achieve further solid-liquid separation. The separated crystals are transported to the crystallization and packaging system for subsequent processing through the centrifugal crystal discharge port 1403, and the separated mother liquor falls into the mother liquor tank 15. After a certain amount of mother liquor has settled in the mother liquor tank 15, the mother liquor is transported back to the separator 1 by the forced circulation pump 2. The mother liquor then passes through the circulating heating evaporation and concentration system of the separator 1, the forced circulation pump 2, and the heat pump unit 3 in sequence for heating and concentration treatment. This improves the evaporation and concentration effect of the liquid and prevents some of the liquid from being discharged from the system without evaporation and concentration.

[0041] A further improvement is that the thickener 13 also has a cooling inlet 1304 and a cooling outlet 1305, which are used for inputting and outputting coolant, respectively.

[0042] By setting up a cooling inlet 1304 and a cooling outlet 1305, cooling water can be easily introduced into the thickener 13 during operation to cool it down. This lowers the temperature of the crystal slurry, reducing the solubility of the solute in the liquid and promoting further supersaturation of the concentrate, thus facilitating the precipitation and sedimentation of salt crystals. Furthermore, the cooling process makes it easier for suspended particles to settle under gravity, improving the separation efficiency of the thickener 13 and shortening the settling time. In addition, low-temperature treatment can suppress the vaporization of volatile components (such as organic solvents and ammonia nitrogen) in the concentrate and crystal slurry, keeping them in the liquid phase for easier subsequent recovery. Moreover, lowering the temperature of the thickener 13 and its internal crystal slurry can slow down the corrosion reaction rate and extend the service life of the thickener 13 and subsequent pipelines.

[0043] A further improvement is that the vacuum pump 8 also has a vacuum cooling inlet 801 and a vacuum cooling outlet 802, which are sequentially connected between the refrigeration outlet 302 and the refrigerant inlet 403.

[0044] With the above design, the subcooled water, i.e. refrigerant, produced by the heat pump unit 3 first passes through the vacuum cooling inlet 801 and the vacuum cooling outlet 802, and then flows through the vacuum pump 8 to cool it down. This prevents the temperature of the vacuum pump 8 from rising after long-term operation. In this way, by cooling the vacuum pump 8, the stable use of the vacuum pump 8 is ensured and its service life is extended.

[0045] Similarly, the forced circulation pump 2 has a circulating cooling inlet 201 and a circulating cooling outlet 202, and the delivery pump 7 has a delivery cooling inlet 701 and a delivery cooling outlet 702. The circulating cooling inlet 201 and the delivery cooling inlet 701 are both connected to the input end of the refrigeration circulation pump 6, and the circulating cooling outlet 202 and the delivery cooling outlet 702 are both connected to the refrigerant storage tank 5.

[0046] With the above design, the refrigeration circulation pump 6 can easily draw the refrigerant temporarily stored in the refrigerant storage tank 5 and deliver it to the forced circulation pump 2 and the transfer pump 7, thereby reducing their temperature and avoiding shortening their service life due to continuous high-temperature operation. In addition, by reducing their temperature, the internal liquid temperature can also be reduced, weakening the corrosiveness of the liquid and further ensuring the normal use of the forced circulation pump 2 and the transfer pump 7, thus extending their service life.

[0047] Specifically, in this embodiment, the upper part of the side wall of the separator 1 has a steam outlet 103 and a feed inlet 101, the lower part of the side wall has a circulation inlet 105, and the bottom is provided with a discharge outlet 102 and a circulation outlet 104. The feed inlet 101 is connected to the preheating outlet 1102, so that the liquid preheated by the preheater 11 can enter the separator 1 through the feed inlet 101; the steam outlet 103 is connected to the steam inlet 401, so that the secondary steam generated during the evaporation and concentration process of the liquid in the separator 1 can be discharged through the steam outlet 103 and enter the condenser 4 through the steam inlet 401 to exchange heat with the refrigerant through the vacuum pump 8; the circulation inlet 105 is discharged through the heating outlet 304, and the circulation outlet 104 is connected to the input end of the forced circulation pump 2, so that the forced circulation pump... During operation, the liquid discharged from the circulation outlet 104 is heated by the forced circulation pump 2 and enters the heat pump unit 3 through the heating inlet 303. After heating, the temperature rises and the liquid is discharged from the heating outlet 304 and flows into the separator 1 through the circulation inlet 105. In this way, the circulation flow of the liquid and the heating, concentration and evaporation treatment are realized. The discharge outlet 102 is connected to the input end of the transfer pump 7, so that after the liquid is concentrated to the preset concentration and forms a crystal slurry, the concentrated crystal slurry is input into the thickener 13 of the solid-liquid separation component for thickening treatment through the transfer pump 7.

[0048] The top of the condensate tank 9 is provided with a negative pressure port 901 that is connected to the input end of the vacuum pump 8, the bottom is provided with a water inlet 902 that is connected to the input end of the condensate pump 10, and the side wall is provided with a water inlet 903 that is connected to the condensate outlet 402.

[0049] The material flow in this embodiment is as follows: liquid feed → preheater 11 → separator 1 → transfer pump 7 → thickener 13 → centrifuge 14 → mother liquor tank 15 / crystals are dispensed outside the system.

[0050] Specifically, the feed liquid treatment process of the low-temperature heat pump evaporator begins with the intelligent feeding and preheating stage. The feed liquid is transported to the preheater 11 via pump 7 for preheating before being pumped into the separator 1. The separator 1 is equipped with a liquid level sensor; once the liquid level is detected to be at a certain level, the vacuum pump 8 starts, reducing the internal pressure of the separator 1 to the -95kPa range, creating a closed-loop feeding environment without power. Upon entering the core evaporation stage, the heat pump unit 3 starts, playing a crucial role. The heat pump unit 3 contains refrigerant and includes a forced circulation heater. Through refrigerant compression, a high-temperature refrigerant is formed. This high-temperature refrigerant is then passed through the forced circulation heater to heat the feed liquid driven by the forced circulation pump 2 to 35-50℃, enabling efficient evaporation of the heated feed liquid under low pressure. Once the feed liquid concentration reaches a preset threshold, the discharge procedure is automatically triggered, and the post-treatment system achieves a closed-loop resource recovery system. The discharged concentrate first enters the thickener 13 for gravity sedimentation, which initially enriches the suspended crystals. Then, it is separated into solid and liquid by centrifuge 14 at a speed of 3000-5000 rpm to obtain crystalline salt with a purity of more than 95%. The mother liquor produced by the separation flows into the mother liquor tank 15 for temporary storage and is then reinjected into the separator 1 for secondary treatment. The entire system, through the design of heat energy reuse and material circulation, controls the original energy consumption to within 30% of that of traditional evaporation technology, forming a complete green treatment chain.

[0051] In the low-temperature heat pump evaporator process, the live steam generated by the heat source 12 enters the preheater 11, which heats the liquid to a set stable temperature. The steam releases latent heat and is converted into condensate, which is discharged from the system through the drain valve 1105. During the heating, evaporation and concentration process, the secondary steam generated enters the condenser 4 and exchanges heat in reverse with the refrigerant circulating water of the heat pump unit 3. The refrigerant temperature drops to below -10°C after passing through the expansion valve, forming subcooled water. A low-temperature wall is formed inside the condenser 4, causing the latent heat released by the steam to condense into liquid water. The condensed liquid water enters the buffer condensate tank 9 and is sent to the outside of the system by the condensate pump 10 at a pressure of 0.2-0.3 MPa.

[0052] In summary, the operation process of the low-temperature evaporator in this embodiment can be divided into three stages: preheating start-up, evaporator stabilization, and concentrate discharge. During operation, the vacuum pump 8 first reduces the internal pressure of the separator 1 to a vacuum of -95 kPa to -95 kPa (corresponding to an absolute pressure of approximately 3-5 kPa), lowering the boiling point of the feed liquid to 35-50°C. At this time, the feed liquid absorbs the heat provided by the heat pump unit 3 (usually generated by the compressor driving the refrigerant circulation) in a low-temperature environment, and the water gradually evaporates into steam. The steam then enters the condenser 4, releases latent heat under the action of the refrigerant, and condenses into liquid regenerated water. The unevaporated material is concentrated into a high-concentration feed liquid, which is finally discharged through the automatic discharge system.

[0053] In industrial applications, this low-temperature heat pump evaporator can handle materials with high concentration, high viscosity, and easy crystallization. It boasts adaptability to various liquid conditions and is easy to maintain, thanks to its modular design of core components. The entire unit features a compact layout and supports vehicle-mounted mobile installation, making it particularly suitable for factories with limited space and temporary processing scenarios. The entire system is fully electrically powered, utilizing the cooling capacity of the heat pump unit to directly condense secondary steam, eliminating the need for external cooling towers or circulating water systems, further reducing the energy consumption of auxiliary equipment by up to 40%. During dynamic operation, the intelligent control system adjusts the vacuum level and evaporation temperature, ensuring the equipment remains within the optimal energy consumption range and avoiding excessive energy loss. Compared to mechanical vapor recompression (MVR) evaporators, the overall energy saving rate is improved by more than 50%.

[0054] In addition, the system designed in this embodiment adopts fully automatic operation control. By controlling the flow rate, temperature, pressure and liquid level, it can achieve automatic evaporation, cleaning, shutdown and alarm operations. It is also equipped with manual valve control for convenient shutdown inspection and maintenance.

[0055] Second Embodiment

[0056] No illustration is provided. The second embodiment of this utility model is a low-temperature heat pump evaporator, which is based on the first embodiment, except that the heat medium outlet 1104 is connected to an electric heating steam generator.

[0057] This design allows the live steam to exchange heat with the liquid feed in the preheater 11 to form condensate, which is then fed into an electric heating steam generator. The electric heating steam generator heats the condensate to form live steam, thus achieving the recycling of soft water and reducing its consumption.

[0058] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A low-temperature heat pump evaporator, characterized in that, include: The system includes a separator, a forced circulation pump, a heat pump unit, a condenser, a refrigerant storage tank, and a refrigeration circulation pump. The heat pump unit has a refrigeration inlet, a refrigeration outlet, a heating inlet, and a heating outlet. The condenser has a steam inlet, a condensation outlet, a refrigerant inlet, and a refrigerant outlet. The separator, the forced circulation pump, the heating inlet, and the heating outlet are connected sequentially. The refrigerant storage tank, the refrigeration circulation pump, the refrigeration inlet, the refrigeration outlet, the refrigerant inlet, and the refrigerant outlet are also connected sequentially. A delivery pump and a solid-liquid separation assembly, wherein the delivery pump is used to input the liquid feed into the separator and to deliver the concentrated crystal slurry to the solid-liquid separation assembly for solid-liquid separation; A vacuum pump, a condensate tank, and a condensate pump are provided. The condensate tank is connected to the condensate outlet and has a negative pressure port connected to the vacuum pump and a water inlet connected to the condensate pump.

2. The low-temperature heat pump evaporator according to claim 1, characterized in that: It also includes a preheater, which has a preheating inlet, a preheating outlet, a heat medium inlet, and a heat medium outlet. The heat medium inlet is used to connect to a heat source, the preheating outlet is connected to the separator, and the preheating inlet is connected to the output end of the delivery pump.

3. The low-temperature heat pump evaporator according to claim 2, characterized in that: The heat source is an electrically heated steam generator.

4. The low-temperature heat pump evaporator according to claim 3, characterized in that: The heat medium outlet is connected to a steam trap.

5. The low-temperature heat pump evaporator according to claim 4, characterized in that: The heat medium outlet is connected to the electric heating steam generator.

6. The low-temperature heat pump evaporator according to claim 1, characterized in that: The vacuum pump also has a vacuum cooling inlet and a vacuum cooling outlet, which are sequentially connected between the refrigeration outlet and the refrigerant inlet.

7. The low-temperature heat pump evaporator according to claim 1, characterized in that: The forced circulation pump has a circulating cooling inlet and a circulating cooling outlet, and the delivery pump has a delivery cooling inlet and a delivery cooling outlet. The circulating cooling inlet and the delivery cooling inlet are both connected to the input end of the refrigeration circulation pump, and the circulating cooling outlet and the delivery cooling outlet are both connected to the refrigerant storage tank.

8. The low-temperature heat pump evaporator according to claim 1, characterized in that: The solid-liquid separation assembly includes a thickener, a centrifuge, and a mother liquor tank. The thickener has a thickening inlet, an overflow outlet, and a thickening outlet. The centrifuge has a centrifugal inlet, a centrifugal drain outlet, and a centrifugal crystal discharge outlet. The thickening inlet is connected to one of the output ends of the delivery pump. The overflow outlet and the centrifugal drain outlet are both connected to the mother liquor tank. The centrifugal crystal discharge outlet is used to connect to the crystallization and packaging system.

9. The low-temperature heat pump evaporator according to claim 8, characterized in that: The mother liquor tank is connected to the input end of the forced circulation pump.

10. The low-temperature heat pump evaporator according to claim 8, characterized in that: The thickener also has a cooling inlet and a cooling outlet, the cooling inlet and the cooling outlet being used for inputting and outputting coolant, respectively.

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