Refrigeration heat pump system based on ion thermal effect of variable temperature extraction solution

Abstract

This invention discloses a refrigeration heat pump system based on the ionic thermal effect of a variable-temperature extraction solution, comprising: a solid-liquid phase change thermodynamic circulation loop, which includes a dissolution endothermic unit, an extraction separation unit, and a trigger crystallization unit connected in sequence for dilution, concentration, and crystallization of the working fluid, respectively; the working fluid in this loop, after being concentrated in the extraction separation unit, can be transported to the trigger crystallization unit in the form of a metastable supersaturated solution; and an ionic liquid regeneration circulation loop, which is coupled to the solid-liquid phase change thermodynamic circulation loop at the extraction separation unit, which includes an extraction separation unit and a regeneration separation unit connected in sequence for realizing water absorption, water drainage, and heat dissipation of the ionic liquid, respectively; the regeneration separation unit is equipped with a heating device; the regeneration separation unit provides water to the dissolution endothermic unit, and the trigger crystallization unit provides crystallization products to the dissolution endothermic unit; this invention can achieve higher concentration solution regeneration, improve refrigeration and heating effects, and is more energy-efficient.

Description

Technical Field

[0001] This invention relates to refrigeration heat pumps, and in particular to a refrigeration heat pump system based on the ionothermic effect of variable temperature extraction solution. Background Technology

[0002] Refrigeration technology is widely used in various fields such as building environmental control, food cold processing, low-temperature storage, and mechanical equipment cooling, profoundly impacting people's daily lives. Since the beginning of the last century, vapor compression refrigeration technology has dominated all refrigeration technologies, consuming 20% ​​of global energy, but also causing serious environmental problems. Traditional refrigerants, such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), have severely damaged the Earth's ozone layer, exacerbating global warming.

[0003] With the entry into force of the Montreal Protocol on the Control of Substances that Deplete the Ozone Layer, the use of Freon refrigerants has been strictly limited. While the use of HFC (hydrofluorocarbon) refrigerants has achieved significant results in reducing ozone damage, it has not completely solved the greenhouse effect problem; its GWP (global warming potential) is as high as 2,000 times that of carbon dioxide. According to the Paris Climate Agreement, since 2015, countries have begun to strictly control greenhouse gas emissions and gradually reduce the use of HFC refrigerants. Therefore, the demand for environmentally friendly refrigerants and new, efficient, and low-carbon refrigeration cycles is becoming increasingly urgent.

[0004] Ion thermal effect refrigeration technology, as an emerging environmentally friendly refrigeration solution, utilizes the endothermic effect during salt dissolution or ion migration to achieve refrigeration, and has advantages such as zero GWP, no compressor, and high energy density.

[0005] Chinese invention patent application CN116989500A discloses a non-fluorine, compressor-free refrigeration cycle system and method based on the ionothermic effect. It includes a premixing chamber, a mixer, a melter, a regenerator, and a crystallizer. The refrigeration cycle is achieved through processes such as mixing a concentrated salt solution with a solid solvent, endothermic melting, electrodialysis regeneration, and exothermic crystallization. This invention eliminates the need for a compressor, significantly improving stability and reliability; it uses a purely environmentally friendly working fluid with zero gas volatile organic compound (GWP), completely eliminating the greenhouse effect caused by fluorinated refrigerants; the working fluid participates in the cycle in a liquid-solid state, resulting in high volumetric energy density and a significant reduction in equipment size.

[0006] However, the aforementioned system uses an electrodialysis unit as a regenerator, utilizing anion and cation semi-permeable membranes and a DC electric field to separate the salt solute from the solvent to regenerate the solution. This method, under high concentration and non-aqueous working fluid (sodium iodide-ethylene carbonate) conditions, suffers from both high energy consumption and a critical bottleneck: the electrodialysis process struggles to regenerate high-concentration salt solutions. This is because during the electrodialysis concentration process, as the solution concentration increases, it easily reaches saturation and crystallizes, leading to ion exchange membrane blockage, system performance degradation, and even system failure. In other words, electrodialysis faces the risk of crystallization while simultaneously concentrating the solution, making it difficult to obtain a high-concentration regenerated solution. This results in low cooling or heating efficiency of the regenerated solution, severely limiting the cooling and heating efficiency and practicality of the ion thermal refrigeration system. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide a refrigeration heat pump system based on the ionic thermal effect of variable temperature extraction solution, which can achieve higher concentration solution regeneration, improve refrigeration and heating effects, and is more energy-efficient.

[0008] Technical solution: To achieve the above objectives, the refrigeration heat pump system based on the ionothermic effect of variable-temperature extraction solution described in this invention includes:

[0009] A solid-liquid phase change thermodynamic loop includes a solution endothermic unit, an extraction separation unit, and a crystallization triggering unit connected in sequence for dilution, concentration, and crystallization triggering of the working fluid, respectively. The working fluid in the loop is concentrated in the extraction separation unit and then transported to the crystallization triggering unit in the form of a metastable supersaturated solution.

[0010] An ionic liquid regeneration loop is coupled to a solid-liquid phase change thermodynamic loop at the extraction and separation unit. The loop includes an extraction and separation unit and a regeneration and separation unit connected in sequence to realize water absorption and water drainage of the ionic liquid, respectively. A heating device is provided in the regeneration and separation unit.

[0011] The regeneration separation unit supplies water to the dissolution endothermic unit, and the trigger crystallization unit supplies crystallized products to the dissolution endothermic unit.

[0012] The working fluid in the solid-liquid phase change thermodynamic loop of this system has supercooling characteristics, meaning it will not crystallize spontaneously even when in a supersaturated state. This allows for complete separation of the concentration and crystallization processes, preventing premature crystallization and blockage during the circulation or within the extraction equipment. Compared to existing technologies, this system can regenerate solutions with higher concentrations, improving subsequent exothermic crystallization and endothermic dissolution processes, thus enhancing heating and cooling effects. Furthermore, this system uses ionic liquids to extract water from the solution for concentration and regeneration of the working fluid in the solid-liquid phase change thermodynamic loop. The regeneration of ionic liquids only requires a low-grade heat source, significantly reducing the overall energy consumption compared to electrodialysis regeneration methods.

[0013] Preferably, the working fluid of the solid-liquid phase change thermodynamic cycle loop is sodium acetate trihydrate and its aqueous solution.

[0014] Sodium acetate trihydrate possesses excellent subcooling properties; its supersaturated solution can remain liquid at room temperature for extended periods without spontaneous crystallization. This characteristic allows it to be concentrated to a supersaturated state in the extraction and separation unit, and the concentrated high-concentration solution can be stably transported to the trigger crystallization unit in a supersaturated liquid state, avoiding the risk of premature crystallization and blockage in pipelines or extraction equipment. Secondly, sodium acetate trihydrate has a high latent heat of phase change of approximately 264 kJ / kg, enabling the system to store or release a large amount of cold / heat within a unit volume, allowing for a reduction in overall system size for the same cooling / heating requirements. Furthermore, the concentration variation of sodium acetate trihydrate and its aqueous solutions allows its melting point to cover a wide temperature range from -18℃ to 58℃. In cooling conditions, -18℃ meets the needs of conventional air conditioning and some refrigeration, while 58℃ effectively dissipates heat to the environment in summer. In heating conditions, -18℃ absorbs heat from the low-temperature environment, while 58℃ is suitable for mainstream heating terminals such as underfloor heating and fan coil units. Most importantly, sodium acetate trihydrate is a green substance with zero ODP (ozone depletion potential) and zero GWP (global warming potential). It is non-toxic, non-flammable, and non-corrosive, and fully complies with international environmental regulations.

[0015] Preferably, the ionic liquid in the ionic liquid regeneration loop has a minimum critical co-solution temperature, exhibits hydrophilicity at the operating temperature of the extraction and separation unit, and exhibits hydrophobicity at the operating temperature of the regeneration and separation unit.

[0016] The fact that ionic liquids have a minimum critical eutectic temperature (LCST) makes this system different from traditional electrodialysis, which requires an external electric field (high energy consumption), or distillation, which requires phase change evaporation (extremely high energy consumption). This invention only requires heating the aqueous ionic liquid to above the LCST, which will automatically transform it into a hydrophobic state and precipitate water. The regeneration process does not require a phase change, and the energy consumption is greatly reduced.

[0017] Preferably, the ionic liquid includes at least one of quaternary phosphonium salt ionic liquids or quaternary ammonium salt ionic liquids.

[0018] This type of ionic liquid possesses LCST characteristics and can achieve low-heat-driven regeneration. When in contact with sodium acetate trihydrate aqueous solution, no side reactions occur, and the two phases separate rapidly with a clear interface, enabling stable extraction and separation.

[0019] Preferably, the ionic liquid is tetrabutylphosphonium-2,4-dimethylbenzenesulfonate or tetrabutylammonium-carboxylate.

[0020] Preferably, the ionic liquid regeneration loop also includes a regulator for adjusting the viscosity of the ionic liquid.

[0021] Ionic liquids typically have high viscosity. Adding appropriate modifiers can reduce their viscosity, improve mass transfer rate and flow performance, reduce pumping power consumption, and enhance overall energy efficiency.

[0022] Preferably, a heat exchanger for exchanging heat between the working fluid flowing into and out of the regeneration separation unit is provided between the extraction separation unit and the regeneration separation unit; the extraction separation unit is provided with a temperature regulating device for maintaining the operating temperature; and a heat dissipation unit for cooling the water is provided between the regeneration separation unit and the dissolution endothermic unit.

[0023] A heat exchanger transfers heat from the high-temperature dehydrated ionic liquid output from the regeneration separation unit to the low-temperature aqueous ionic liquid entering the regeneration unit, significantly reducing the heat required for regeneration and improving the overall system energy efficiency ratio. The internal cooling device dissipates heat generated during the mixing process, maintaining the operating temperature of the extraction separation unit at approximately 30°C to preserve the hydrophilicity of the ionic liquid. The heat dissipation unit ensures that the water entering the dissolution endothermic unit is not excessively hot, guaranteeing that the dissolution endothermic unit can effectively absorb external heat and output sufficient cooling capacity.

[0024] Preferably, the regeneration separation unit is equipped with a separation device based on density difference to separate ionic liquid and water, which is a centrifugal separation device or a gravity sedimentation separation device.

[0025] By setting up a gravity settling zone or centrifugal separation device based on density difference in the regeneration separation unit, rapid physical stratification of water and ionic liquid is achieved, avoiding membrane fouling or clogging problems that may occur with membrane separation, and ensuring the purity of regenerated water and ionic liquid.

[0026] Preferably, the regeneration separation unit is heated by an external heat source with a temperature not exceeding 80°C.

[0027] The heat source used by the regeneration and separation unit has a temperature not exceeding 80°C, which is a low-grade heat source. This allows the system to use industrial waste heat or solar energy as driving energy, reducing operating costs.

[0028] Preferably, the crystallization triggering unit is equipped with a crystallization triggering device, which is one or more of an ultrasonic generator, a mechanical vibration device, or a seed crystal delivery device.

[0029] A crystallization triggering device is installed in the crystallization unit, enabling precise control of the crystallization process. This allows the system to actively trigger the crystallization of the supersaturated solution when heating is required, releasing heat and preventing disordered heat release or pipeline blockage caused by spontaneous crystallization. This controllability is based on the subcooling characteristics of the working fluid, meaning that the supersaturated solution can exist stably without triggering, and only releases energy when triggered.

[0030] Beneficial effects: Utilizing the supercooling stability of sodium acetate trihydrate solution, the solution remains stable and does not spontaneously crystallize even when concentrated to a supersaturated state. This allows for higher concentrations of sodium acetate trihydrate solution without causing system blockage. The high concentration of sodium acetate trihydrate solution improves subsequent cooling and heating effects. Furthermore, this system uses ionic liquid extraction to concentrate the water in the sodium acetate trihydrate solution. The aqueous ionic liquid can be regenerated using a low-grade heat source, reducing system energy consumption. In addition, the high phase change enthalpy of sodium acetate trihydrate endows the system with high energy storage density, significantly reducing equipment size. Its wide operating temperature range of -18℃ to 58℃ allows for flexible adaptation to various cooling and heating scenarios. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the system structure. Detailed Implementation

[0032] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0033] As shown in the figure, the refrigeration heat pump system based on the ionothermic effect of variable temperature extraction solution according to the present invention includes:

[0034] A solid-liquid phase change thermodynamic loop includes a solution endothermic unit 1, an extraction and separation unit 2, and a triggering crystallization unit 3, which are connected in sequence for diluting, concentrating, and triggering crystallization of the working fluid, respectively. An internal cooling device 9 (temperature regulation device) is provided in the extraction and separation unit 2. After being concentrated in the extraction and separation unit 2, the working fluid in the loop can be transported to the triggering crystallization unit 3 in the form of a metastable supersaturated solution.

[0035] An ionic liquid regeneration circulation loop is coupled to a solid-liquid phase change thermodynamic circulation loop at the extraction and separation unit 2. The loop includes an extraction and separation unit 2, a regeneration and separation unit 4, and a heat dissipation unit 8, which are connected in sequence to realize the ionic liquid water absorption, water drainage, and heat dissipation, respectively. A heating device 5 is provided in the regeneration and separation unit 4.

[0036] The regeneration separation unit 4 supplies water to the dissolution endothermic unit 1, and the trigger crystallization unit 3 supplies crystallization products to the dissolution endothermic unit 1.

[0037] The dissolution endothermic unit 1, serving as the system's evaporation component, is designed as a shell-and-tube heat exchanger. The shell side is filled with sodium acetate trihydrate crystals, while the tube side flows with a refrigerant such as ethylene glycol or water. The shell-and-tube heat exchanger structure is a conventional existing device, and its specific construction will not be detailed here. A spray device is installed above the shell to evenly spray regenerated water from the regeneration separation unit 4. Inside, there are copper fins spaced 2-5 mm apart and a stirring device for mixing the water and sodium acetate trihydrate crystals. The stirring device prevents the crystals from settling, and the copper fins significantly increase the heat exchange area; together, they accelerate the endothermic dissolution process.

[0038] Sodium acetate trihydrate (CH3COONa·3H2O) and its aqueous solution are used as working fluids in solid-liquid phase change thermodynamic cycles. They have a melting point of 58°C, a latent heat of phase change as high as 264 kJ / kg, and excellent supercooling properties; the supersaturated solution can remain liquid for extended periods at room temperature. During the cycle, the mass fraction of the dilute solution is controlled at 20%-30%, and the mass fraction of the concentrated solution is controlled at 55%-65%.

[0039] Extraction separation unit 2, serving as a coupling component, is designed as a countercurrent contact packed tower. The tower is filled with hydrophobic ceramic Raschig rings or structured packing. The dilute salt solution (sodium acetate trihydrate solution) flowing out of dissolution endothermic unit 1 enters from the bottom of the tower. The concentrated ionic liquid (dehydrated ionic liquid) output from regeneration separation unit 4 is sprayed from the top of the tower to extract water from the dilute salt solution. This top spraying method increases the liquid-liquid contact area, improving the extraction effect. Utilizing the strong hydrophilicity of the ionic liquid at low temperatures (20–30°C, which is the operating temperature of extraction separation unit 2), water molecules are driven to rapidly transfer from the dilute salt solution phase to the ionic liquid phase. Extraction separation unit 2 is equipped with an internal cooling device 9 to better dissipate the heat generated during the mixing process of the dilute salt solution and ionic liquid, maintaining the internal operating temperature of extraction separation unit 2 at the set temperature to preserve the hydrophilicity of the ionic liquid. If the mixing process is slow and less heat is generated, the internal cooling device 9 may not be necessary.

[0040] In this application, the working fluid flowing in the ionic liquid regeneration circulation loop is mainly an ionic liquid. This ionic liquid has a low critical eutectic temperature, exhibiting hydrophilicity at the operating temperature of the extraction and separation unit and hydrophobicity at the operating temperature of the regeneration and separation unit. One or more mixtures of quaternary phosphonium salt ionic liquids and quaternary ammonium salt ionic liquids can be used. In this embodiment, tetrabutylphosphonium-2,4-dimethylbenzenesulfonate is used, with a lowest critical eutectic temperature (LCST) of 36–39°C. Besides tetrabutylphosphonium-2,4-dimethylbenzenesulfonate, tetrabutylammonium carboxylate can also be used. After the ionic liquid extracts water, it naturally separates and stratifies with the sodium acetate trihydrate solution. A corresponding pump 6 is used to transport the concentrated sodium acetate trihydrate solution and the water-absorbing ionic liquid from the extraction and separation unit 2 to the trigger crystallization unit 3 and the regeneration and separation unit 4, respectively.

[0041] The triggered crystallization unit 3, serving as the system's exothermic component, integrates an ultrasonic transducer probe as a crystallization triggering device, with a frequency set between 20-40 kHz. When the supersaturated solution flows through, the cavitation effect generated by the ultrasonic waves provides nucleation sites, rapidly inducing exothermic crystallization. This achieves controllable triggering of the crystallization process, releasing the latent heat of the supersaturated solution at specific locations and preventing pipe blockage. The crystallization triggering device can also employ a mechanical vibration device or a seed crystal dispensing device.

[0042] The regeneration separation unit 4 is designed as a settling tank with a heating jacket (i.e., heating device 5). Industrial waste hot water, solar flat-plate hot water, or geothermal water at temperatures of 80°C or below are introduced into the jacket. It utilizes the LCST characteristic of ionic liquids; when the temperature exceeds the critical point (e.g., 50–70°C), the ionic liquid transforms into a hydrophobic state, physically separating from the water. The tank is equipped with baffles, an overflow weir at the top to collect water, and an outlet at the bottom to collect the ionic liquid. The settling tank is a conventional existing device, and its specific structure will not be detailed here. Besides using a gravity settling separation device like the settling tank, the regeneration separation unit 4 can also use a centrifugal separation device to separate the ionic liquid and water. The regeneration separation unit 4 eliminates the high-energy-consuming phase change evaporation, achieving efficient separation using a low-grade heat source, significantly reducing the overall energy consumption of the system.

[0043] A heat exchanger 7 is provided between the extraction separation unit 2 and the regeneration separation unit 4 to exchange the heat of the working fluid flowing into and out of the regeneration separation unit 4. The high-temperature dehydrated ionic liquid flowing out of the regeneration separation unit 4 can heat the low-temperature water-absorbing ionic liquid flowing into it to preheat it, effectively recover heat, and improve the overall energy utilization rate of the system.

[0044] The water separated by the regeneration separation unit 4 is supplied to the dissolution heat absorption unit 1. A heat dissipation unit 8 can also be set between the two to cool the water. If the pipe between the two is long enough to cool the water to a preset temperature before it enters the dissolution heat absorption unit 1, the heat dissipation unit 8 may not be set. The heat dissipation unit 8 and the internal cooling device 9 are conventional heat exchange devices, such as conventional water cooling devices.

[0045] The ionic liquid regeneration loop also includes a regulator for adjusting the viscosity of the ionic liquid. In this embodiment, isooctanol is used to simultaneously meet the four constraints of extremely low water solubility, high boiling point and low volatility, extremely low kinetic viscosity, and not disrupting the LCST mechanism.

[0046] Pump 6 is installed between each unit for the transfer of the working fluid; see details below. Figure 1 .

[0047] The system can also be equipped with an intelligent control system: when the user-side heat load (or cold load) changes, the crystallization rate and dissolution endothermic rate are controlled by adjusting the speed of pump 6 between extraction separation unit 2 and crystallization trigger unit 3 and the power of the crystallization trigger device, thereby achieving regulation of output cooling or heating. When the heat load (or cold load) increases, the speed of pump 6 and the power of the crystallization trigger device should both be increased, and vice versa. In addition, the system is equipped with heating tape, i.e., electric heating device, on key pipelines to prevent accidental crystallization blockage, and a shutdown cleaning procedure is also provided.

[0048] The workflow of this system is as follows:

[0049] The endothermic dissolution process occurs in dissolution endothermic unit 1: pure water (approximately 70°C) from regeneration separation unit 4 is cooled to approximately 30°C via heat dissipation unit 8 (e.g., cooling tower circulating water), and then mixed with sodium acetate trihydrate crystal slurry (approximately 45-50°C) from trigger crystallization unit 3. Driven by the concentration gradient, the solid crystals undergo a vigorous endothermic dissolution reaction, overcoming the sensible heat of the fluid itself, causing the temperature of the mixture to drop to approximately 5°C, outputting cooling energy, and forming a low-temperature dilute solution with a mass fraction of approximately 28%.

[0050] The extraction and concentration process occurs in extraction separation unit 2: a low-temperature dilute solution is countercurrently contacted with a low-temperature hydrophilic ionic liquid. Driven by the chemical potential difference, water molecules spontaneously transfer to the ionic liquid phase, increasing the concentration of sodium acetate trihydrate solution to approximately 60%. To maintain the hydrophilic activity of the ionic liquid, extraction separation unit 2 is equipped with an internal cooling device 9, through which circulating water from a cooling tower is introduced to remove the heat generated during the mixing process, maintaining the unit's operating temperature at approximately 30°C. After extraction, due to the lack of nucleation induction, the high-concentration solution exhibits a stable supersaturated liquid state (metastable state) and is discharged from the bottom of the tower to be transported to trigger crystallization unit 3.

[0051] The triggered crystallization process occurs in triggered crystallization unit 3: the supersaturated salt solution is pumped to triggered crystallization unit 3, and under the triggering of physical fields such as ultrasound, the metastable state is broken, crystallization occurs rapidly and the latent heat of phase change is released, the fluid temperature jumps to nearly 58°C, heat is released to the environment or used for terminal heating, and the crystallized product after heat release (temperature drops to about 45-50°C) flows back to mixing and dissolving unit 1 to participate in the next cycle.

[0052] The variable-temperature regeneration process of the ionic liquid occurs in regeneration separation unit 4: After absorbing water, the ionic liquid is preheated by heat exchanger 7 and then enters regeneration separator 4 where it is heated to a preset temperature, such as 70°C, by a driven heat source (e.g., 80°C). As the ionic liquid crosses its lowest critical eutectic temperature (LCST), it undergoes a hydrophilic-hydrophobic phase transition, precipitating water and forming liquid-liquid stratification. The upper layer of water is pumped to the dissolution absorber after passing through a heat dissipation unit, while the lower layer of concentrated ionic liquid is pumped to heat exchanger 7 for cooling and then returned to extraction separation unit 2 to restore its hydrophilic activity.

Claims

1. A refrigeration heat pump system based on the ionothermic effect of a variable-temperature extraction solution, characterized in that, include: A solid-liquid phase change thermodynamic loop includes a solution endothermic unit, an extraction separation unit, and a trigger crystallization unit connected in sequence for dilution, concentration, and crystallization of the working fluid, respectively; the working fluid in the loop is concentrated in the extraction separation unit and then transported to the trigger crystallization unit in the form of a metastable supersaturated solution. An ionic liquid regeneration loop is coupled to a solid-liquid phase change thermodynamic loop at the extraction and separation unit. The loop includes an extraction and separation unit and a regeneration and separation unit connected in sequence to realize water absorption and water drainage of the ionic liquid, respectively. A heating device is provided in the regeneration and separation unit. The regeneration separation unit supplies water to the dissolution endothermic unit, and the trigger crystallization unit supplies crystallized products to the dissolution endothermic unit.

2. The system according to claim 1, characterized in that: The working fluid in the solid-liquid phase change thermodynamic cycle loop is sodium acetate trihydrate and its aqueous solution.

3. The system according to claim 2, characterized in that: The ionic liquid in the ionic liquid regeneration loop has a minimum critical co-solution temperature characteristic, exhibiting hydrophilicity at the operating temperature of the extraction and separation unit and hydrophobicity at the operating temperature of the regeneration and separation unit.

4. The system according to claim 3, characterized in that: The ionic liquid includes at least one of quaternary phosphonium salt ionic liquids or quaternary ammonium salt ionic liquids.

5. The system according to claim 4, characterized in that: The ionic liquid is tetrabutylphosphonium-2,4-dimethylbenzenesulfonate or tetrabutylammonium-carboxylate.

6. The system according to claim 3, characterized in that: The ionic liquid regeneration loop also includes a regulator for adjusting the viscosity of the ionic liquid.

7. The system according to claim 1, characterized in that: A heat exchanger is provided between the extraction separation unit and the regeneration separation unit for exchanging heat between the working fluid flowing into and out of the regeneration separation unit; the extraction separation unit is provided with a temperature regulating device for maintaining the working temperature; and a heat dissipation unit is provided between the regeneration separation unit and the dissolution heat absorption unit for cooling the water.

8. The system according to claim 1, characterized in that: The regeneration separation unit is equipped with a separation device based on density difference to separate ionic liquids and water. The separation device is either a centrifugal separation device or a gravity sedimentation separation device.

9. The system according to claim 1, characterized in that: The regeneration and separation unit is heated by an external heat source with a temperature not exceeding 80°C.

10. The system according to claim 1, characterized in that: The triggered crystallization unit is equipped with a crystallization triggering device, which is one or more of an ultrasonic generator, a mechanical vibration device, or a seed crystal delivery device.

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