SYSTEM FOR COUPLING A SUPERCRITICAL CARBON DIOXIDE POWER GENERATION CYCLE AND LITHIUM EXTRACTION FROM BRINE

Abstract

A system for coupling power generation from a supercritical carbon dioxide cycle and lithium extraction from brine is provided. The system comprises an absorption heat pump unit, a supercritical carbon dioxide cycle power generation unit, and a lithium extraction unit from brine. This system organically combines the exothermic characteristics of the waste heat from the supercritical carbon dioxide cycle system with the endothermic characteristics of the lithium extraction system from brine, and the waste heat is recycled in a cascade as a heat source in the lithium extraction system from brine.Therefore, the total energy consumption of power generation and lithium extraction, and the total investment in system equipment can be effectively reduced, and the efficiency of lithium adsorption and precipitation in the brine lithium extraction system can be significantly improved.

Description

1 / 22 SUPERCRITICAL CARBON DIOXIDE CYCLE POWER GENERATION AND LITHIUM EXTRACTION COUPLING SYSTEM BRINE FIELD

[0001] This disclosure relates to the field of lithium extraction from brine and, specifically, to a supercritical carbon dioxide cycle power generation coupling system and lithium extraction from brine. BACKGROUND

[0002] The supercritical carbon dioxide cycle has great potential for applications in power generation, such as coal-fired power generation, concentrated solar power generation, geothermal power generation, and waste heat recovery, due to the high efficiency of the thermal cycle, its compact structure, and small size. The waste heat temperature of a cooler at the cold end of the supercritical carbon dioxide cycle ranges from 100 to 200 °C. In a stand-alone supercritical carbon dioxide cycle power generation system, the carbon dioxide working fluid must be cooled to a temperature between 32 and 40 °C before entering a compressor to ensure the high efficiency of the cycle's power generation system.This cooling stage not only wastes a large amount of low-quality waste heat, but also requires an adequate supply of cooling water. Industrial water supply is relatively limited, and there is a high demand for water conservation and reduced consumption in the dry, water-scarce region of northwest China, such as Qinghai. This contradicts the high consumption of cooling water in [the region]. 1934713 of 23 2 / 22 the supercritical carbon dioxide cycle power generation system.

[0003] From another perspective, lithium and its compounds are widely used and have significant strategic value for the development of China. Salt lakes in western China, such as Qinghai, are important potential lithium resource production areas. Lithium resources in salt lakes account for more than 60% of the country's total. However, the concentration of lithium in China's salt lakes is relatively low, and the process of extracting lithium salt from the brines is complex and requires a large amount of low-grade thermal energy. This low-grade thermal energy is generally supplied by steam, which also consumes a certain amount of industrial water. The lithium precipitation reaction requires a high reaction temperature to maintain a high yield and high purity of lithium carbonate.Brine in an adsorption tower can help increase the adsorption capacity of an adsorbent at a high adsorption temperature, thus increasing adsorption yield. However, in a separate lithium extraction system from brine, a large amount of steam is needed to raise and maintain the temperature during lithium precipitation and adsorption, significantly increasing the operating cost of the lithium extraction process from brine.

[0004] In the related art, the supercritical carbon dioxide cycle power generation system and the brine lithium extraction system have drawbacks such as high consumption of industrial water and steam, which significantly increases the operating cost of the power generation system and the brine lithium extraction system. The solution is to increase the working temperature of the lithium precipitation reaction section and the adsorption section in the brine lithium extraction system. 1934713 of 23 3 / 22 involves high energy and steam consumption, which is not technically competitive due to the high initial cost of operating the lithium brine extraction system separately. Direct discharge of waste heat from the cold end of the supercritical carbon dioxide power generation system also wastes a significant amount of thermal energy resources and consumes a large quantity of cooling water. SUMMARY

[0005] One objective of this disclosure is to provide a system for coupling supercritical carbon dioxide cycle power generation and lithium extraction from brine. The system can effectively reduce the total energy consumption of power generation and lithium extraction, reduce the total investment in system equipment, and significantly improve the efficiency of lithium adsorption and precipitation in the lithium extraction system from brine.

[0006] To achieve the above objective, this disclosure provides a supercritical carbon dioxide cycle power generation and brine lithium extraction coupling system, comprising an absorption heat pump unit, a supercritical carbon dioxide cycle power generation unit, and a brine lithium extraction unit, wherein the absorption heat pump unit includes a driving heat source inlet, a driving heat source outlet, a material to be heated inlet, and a heated material outlet; the brine lithium extraction unit includes a brine inlet and a lithium extraction device, and the lithium extraction device has a raw material inlet, a heating medium inlet, and a heating medium outlet; the brine inlet is in communication with the material inlet 1934713 of 23 4 / 22 to heat from the absorption heat pump unit, and the heated material outlet is in communication with the raw material inlet of the lithium extraction device; the supercritical carbon dioxide cycle power generation unit includes a carbon dioxide cycle cold end outlet and a carbon dioxide cycle cold end inlet; and the carbon dioxide cycle cold end outlet is in communication with the heating medium inlet of the brine lithium extraction unit and / or the driving heat source inlet of the absorption heat pump unit, and the supercritical carbon dioxide cycle cold end inlet of the carbon dioxide cycle power generation unit is in communication with the heating medium outlet of the brine lithium extraction unit and / or the driving heat source outlet.

[0007] Through the aforementioned technical solution, the coupling system integrates the supercritical carbon dioxide cycle power generation system and the brine lithium extraction system. Instead of directly releasing the waste heat carried by the carbon dioxide working fluid at the cold end of the supercritical carbon dioxide cycle into a chiller, it recycles the waste heat in a cascade as a heat source in the brine lithium extraction system. This system achieves quality over quantity by utilizing an absorption heat pump based on the principle of temperature zone adaptation and energy cascade utilization. In this way, it organically couples the exothermic characteristics of the waste heat from the supercritical carbon dioxide cycle system with the endothermic characteristics of the brine lithium extraction system.Compared to a supercritical carbon dioxide cycle system and a salt lake lithium extraction system operating separately, the coupling system provided by this disclosure can reduce. 1934713 of 23 5 / 22 effectively reduce the total energy consumption of power generation and lithium extraction, reduce the total investment in system equipment, and significantly improve the efficiency of lithium adsorption and precipitation in lithium extraction from the brine system.

[0008] Other features and benefits of this disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings are intended to provide a further understanding of this disclosure and form a part of this document. The accompanying drawings and the implementations below are used together to explain this disclosure rather than to limit it. In the accompanying drawings:

[0010] FIG. 1 is a process flow diagram of an implementation of a supercritical carbon dioxide cycle power generation coupling system and brine lithium extraction in accordance with this disclosure.

[0011] Description of the drawings

[0012] 1. Electric generator, 2. Turbine, 3. High temperature regenerator, 4. Third heater, 5. Low-temperature regenerator, 6. First compressor, 7. Three-way diverter control valve, 8. Second compressor, 9. Three-way mixing control valve, 10. Cooler, 11. Adsorption tower, 12. Nanofiltration membrane section, 13. Preheater, 14. First heater, 15. Gas-liquid separator, 16. Second heater, 17. Sodium carbonate solution tank, 18. Lithium precipitation reactor, 19. Generator, 20. Condenser, 21. Solution exchanger, 22. Steam valve, 23. Solution pump, 24. Solution valve, 25. Absorber, 26. Desorber, and 27. Filter. 1934713 of 23 6 / 22 DETAILED DESCRIPTION

[0013] Implementations of this disclosure are described in detail below. It should be understood that the implementations described herein are used simply to describe and explain this disclosure, and are not intended to limit this disclosure.

[0014] As shown in FIG. 1, this disclosure provides a supercritical carbon dioxide cycle power generation and brine lithium extraction coupling system, comprising an absorption heat pump unit, a supercritical carbon dioxide cycle power generation unit, and a brine lithium extraction unit, wherein the absorption heat pump unit includes a driving heat source inlet, a driving heat source outlet, a material to be heated inlet, and a heated material outlet; the brine lithium extraction unit includes a brine inlet and a lithium extraction device, and the lithium extraction device has a raw material inlet, a heating medium inlet, and a heating medium outlet;The brine inlet is in communication with the material to be heated inlet of the absorption heat pump unit, and the heated material outlet is in communication with the raw material inlet of the lithium extraction device; the supercritical carbon dioxide cycle power generation unit includes a carbon dioxide cycle cold end outlet and a carbon dioxide cycle cold end inlet; and the carbon dioxide cycle cold end outlet is in communication with the heating medium inlet of the brine lithium extraction unit and / or the driving heat source inlet of the absorption heat pump unit, and the supercritical carbon carbon dioxide cycle cold end inlet of the power generation unit; 1934713 of 23 7 / 22 Carbon dioxide cycle energy is in communication with the outlet of the heating medium of the brine lithium extraction unit and / or the outlet of the driving heat source.

[0015] The inventor of this disclosure discovered that the exothermic temperature section of the waste heat at the cold end of the existing supercritical carbon dioxide cycle power generation system essentially corresponds to the endothermic temperature section of the brine lithium extraction system medium to be heated. For example, this medium can be used as a heating medium to raise and maintain the temperature during lithium precipitation and adsorption in the brine lithium extraction system. The coupling system provided by this disclosure couples the supercritical carbon dioxide cycle power generation unit to the brine lithium extraction unit via an absorption heat pump unit, which does not directly release the waste heat carried by the carbon dioxide working fluid in the supercritical carbon dioxide unit.Instead of an extreme cold cycle in the chiller, the system recycles waste heat in a cascade as a heat source in the lithium extraction system from the brine. This system achieves quality in exchange for quantity by utilizing a portion of the waste heat through an absorption heat pump based on the principle of temperature zone adaptation and energy cascade utilization. This organically couples the exothermic characteristics of the waste heat from the supercritical carbon dioxide cycle system with the endothermic characteristics of the lithium extraction system from the brine. Compared to a supercritical carbon dioxide cycle system and a salt lake lithium extraction system operating separately, the novel coupling system described here can effectively reduce the overall energy consumption of power generation and lithium extraction, thus lowering the total investment. 1934713 of 23 8 / 22 system equipment, and significantly improve the efficiency of lithium extraction from the brine system.

[0016] According to this disclosure, the cold end outlet of the supercritical carbon dioxide cycle power generation unit, the heating medium inlet of the brine lithium extraction unit, and the driving heat source inlet of the absorption heat pump unit may be connected in series, in parallel, or in series and parallel. The heating medium inlet of the brine lithium extraction unit originates from a device that requires heat consumption in the brine lithium extraction unit, for example, including one or more heating medium inlets from the lithium precipitation reaction stage, one heating medium inlet from the adsorption stage, and one heating medium inlet from the evaporation concentration stage.

[0017] In an implementation of this disclosure, the cold end outlet of the carbon dioxide cycle of the supercritical carbon dioxide cycle power generation unit is in sequential communication with the heating medium inlet of the brine lithium extraction unit and the driving heat source inlet of the absorption heat pump unit.According to an embodiment of this disclosure, the cold end outlet of the carbon dioxide cycle is in communication with the heating medium inlet of the brine lithium extraction unit, the heating medium outlet of the brine lithium extraction unit is in communication with the driving heat source inlet of the absorption heat pump unit, and the driving heat source outlet is in communication with the cold end inlet of the carbon dioxide cycle of the carbon dioxide cycle power generation unit. 1934713 of 23 9 / 22 supercritical.

[0018] In another implementation of this disclosure, the cold end outlet of the carbon dioxide cycle of the supercritical carbon dioxide cycle power generation unit is in sequential communication with the drive heat source inlet of the absorption heat pump unit and the heating medium inlet of the brine lithium extraction unit. According to one embodiment of this description, the cold end outlet of the carbon dioxide cycle is in communication with the drive heat source inlet of the absorption heat pump unit, and the drive heat source outlet is in communication with the heating medium inlet of the brine lithium extraction unit.and the outlet of the heating medium of the brine lithium extraction unit is in communication with the cold end inlet of the carbon dioxide cycle of the supercritical carbon dioxide cycle power generation unit.

[0019] In another implementation of this disclosure, the cold end outlet of the carbon dioxide cycle is in communication with the drive heat source inlet of the absorption heat pump unit and the heating medium inlet of the brine lithium extraction unit separately, and the drive heat source outlet and the heating medium outlet of the brine lithium extraction unit are in communication respectively with the cold end inlet of the carbon dioxide cycle of the supercritical carbon dioxide cycle power generation unit, i.e., the drive heat source of the absorption heat pump unit and the heating medium side of the brine lithium extraction unit are connected in parallel. 1934713 of 23 10 / 22

[0020] The inventor of this disclosure further discovered that the waste heat carried by the carbon dioxide working substance at the cold end of the supercritical carbon dioxide cycle power generation unit can be recycled in a cascade as a heat source during the evaporative concentration and precipitation of lithium in the brine lithium extraction system. In one implementation of this disclosure, the lithium extraction device includes an evaporative concentration device and a lithium precipitation reaction device;The outlet of the cold end of the carbon dioxide cycle is in communication with a heating medium inlet of the evaporative concentration device, and a heating medium outlet of the evaporative concentration device is in communication with a heating medium inlet of the lithium precipitation reaction device, so that the working substance of carbon dioxide at the cold end of the supercritical carbon dioxide cycle power generation unit is used as a heating medium in the evaporative concentration device and as a heating medium in the lithium precipitation reaction device sequentially;Furthermore, an outlet of the heating medium of the lithium precipitation reaction device is in communication with the inlet of the driving heat source of the absorption heat pump unit, to further recycle the waste heat of the carbon dioxide working substance at the cold end.

[0021] In one implementation, for example, the evaporative concentration device is either a single-stage evaporative concentration device or a multi-stage evaporative concentration device; and furthermore, the evaporative concentration device includes a first heater 14 and a gas-liquid separator 15, and the lithium precipitation reaction device includes a second heater 16 and a 1934713 of 23 11 / 22 lithium precipitation reactor 18. In addition, an endothermic side outlet of the first heater 14 is in communication with an inlet of the gas-liquid separator 15, a liquid phase outlet of the gas-liquid separator 15 in communication with an endothermic side inlet of the second heater 16, and an endothermic side outlet of the second heater 16 is in communication with a feedstock inlet of the lithium precipitation reactor 18;The outlet of the cold end of the carbon dioxide cycle is in communication with an inlet on the exothermic side of the first heater 14, and an outlet on the exothermic side of the first heater 14 is in communication with an inlet on the exothermic side of the second heater 16, so that the working substance of carbon dioxide at the cold end of the power generation unit of the supercritical carbon dioxide cycle enters the first heater 14 of the evaporative concentration device and the second heater 16 of the lithium precipitation reaction device sequentially as a heating medium; and furthermore, an exothermic side outlet of the second heater 16 is in communication with the inlet of the driving heat source of the absorption heat pump unit.

[0022] Furthermore, to improve the lithium extraction effect of the brine lithium extraction unit, the brine lithium extraction unit further includes an adsorption device and a membrane separation device that are in sequential communication; the brine inlet of the brine lithium extraction unit can be in communication with a material to be adsorbed inlet of the adsorption device, and a lithium-rich permeate outlet of the membrane separation device is in communication with an endothermic side inlet of the adsorption device of the first heater 14, so that the brine raw material entering the lithium extraction of the brine unit is sequentially subjected to adsorption to remove impurities and separation by 1934713 of 23 12 / 22 membrane for removing divalent ions before entering the evaporation concentration device. The adsorption device includes, for example, an adsorption tower 11. An adsorbent is a conventional type in the art. The membrane separation device includes, for example, a nanofiltration membrane section 12.

[0023] In one implementation, to further improve the energy efficiency of the device, the lithium extraction device further includes a preheater 13; an endothermic side inlet of the preheater 13 is in communication with the lithium-rich permeate outlet of the membrane separation device, and an endothermic side outlet of the preheater is in communication with the endothermic side inlet of the first heater 14; and a gas-phase outlet of the gas-liquid separator 15 is in communication with an exothermic side inlet of the preheater 13, to preheat the brine entering the evaporation concentration device with the heat from the vapor separated by the gas-liquid separator 15.

[0024] In one implementation, the lithium precipitation reaction device further includes a sodium carbonate solution inlet, and the sodium carbonate solution inlet is in communication with the endothermic side inlet of the second heater 16, so that the sodium carbonate solution enters the lithium precipitation reactor 18 for reaction after preheating in the second heater 16. The sodium carbonate solution inlet may be in communication with a sodium carbonate solution tank 17.

[0025] In one implementation, the brine lithium extraction unit further includes a filter 27, and the filter 27 is arranged between the brine inlet and the material to be heated inlet of the absorption heat pump unit. 1934713 of 23 13 / 22

[0026] In other implementations of this description, the brine lithium extraction unit may further include a pretreatment device or a posttreatment device to remove boron and iron.

[0027] According to one implementation of this disclosure, the absorption heat pump unit includes a first type of absorption heat pump, and the first type of absorption heat pump includes a generator 19, a condenser 20, an absorber 25, and a desorber 26; an exothermic side inlet of the generator 19 forms the drive heat source inlet to be in communication with the heating medium outlet of the brine lithium extraction unit. According to one implementation, the lithium extraction device of the brine lithium extraction unit includes the evaporation concentration device and the lithium precipitation reaction device, and the exothermic side inlet of the generator 19 is in communication with the heating medium outlet of the lithium precipitation reaction device.

[0028] Furthermore, an exothermic side outlet of the generator 19 forms the driving heat source outlet to communicate with the cold-end inlet of the carbon dioxide cycle; and an endothermic side inlet of the desorber 26 forms the material to be heated inlet to communicate with the brine inlet. An endothermic side outlet of the desorber 26 communicates with an endothermic side inlet of the condenser 20 of the adsorption heat pump unit, and an endothermic side outlet of the condenser 20 forms the heated material outlet to communicate with the raw material inlet of the lithium extraction device. In this implementation, the carbon dioxide working fluid at the cold end of the supercritical carbon dioxide cycle power generation unit is used as the driving heat source for the heat pump. 1934713 of 23 14 / 22 absorption heat after providing heat for lithium extraction from brine, and the brine raw material is preheated through the absorption heat pump before entering the brine lithium extraction unit, to further recycle the waste heat of the carbon dioxide working substance at the cold end.

[0029] In one implementation, the first type of absorption heat pump may be a water and lithium bromide heat pump and / or an ammonia and water heat pump. The first type of absorption heat pump may further include a solution exchanger 21, a steam valve 22, a solution pump 23, and a solution valve 24. The first type of absorption heat pump may be a single-stage absorption heat pump or a multi-stage absorption heat pump.

[0030] According to one implementation of this disclosure, the supercritical carbon dioxide cycle power generation unit is a recompression supercritical carbon dioxide cycle power generation unit. In other implementations of this description, the supercritical carbon dioxide cycle power generation unit may be a simple regenerative cyclic supercritical carbon dioxide cycle power generation unit or a partial-cooling cyclic supercritical carbon dioxide cycle power generation unit.

[0031] In one implementation, the supercritical carbon dioxide cycle power generation unit further includes an electric generator 1, a turbine 2, a high-temperature regenerator 3, and a low-temperature regenerator 5, with electric generator 1 coaxially connected to turbine 2. An outlet of turbine 2, an exothermic side of the high-temperature regenerator 3, and an inlet of the exothermic side of the low-temperature regenerator are in sequential communication. An exothermic side outlet 1934713 of 23 15 / 22 of the low-temperature regenerator 5 is in communication with the cold-end outlet of the carbon dioxide cycle. Thus, the carbon dioxide working fluid from the turbine outlet 2 passes through the high-temperature regenerator 3 and the low-temperature regenerator 5 to recycle heat, and the carbon dioxide working fluid with the recycled heat is introduced outside the supercritical carbon dioxide cycle power generation unit from the cold-end outlet of the carbon dioxide cycle as the carbon dioxide working fluid at the cold end to recycle more heat in the same.

[0032] In one implementation, the supercritical carbon dioxide cycle power generation unit further includes a cooler 10, a first compressor 6, and a third heater 4. The cold end inlet of the carbon dioxide cycle, an exothermic side of the cooler 10, and an inlet of the first compressor 6 are in sequential communication. An outlet of the first compressor 6, an endothermic side of the low-temperature regenerator 5, an endothermic side of the high-temperature regenerator 3, and an inlet of the endothermic side of the third heater 4 are in sequential communication. An endothermic side outlet of the third heater 4 is in communication with an inlet of the turbine 2.In one implementation, the carbon dioxide working substance, after recycling waste heat through the brine lithium extraction unit and the absorption heat pump unit, returns to the supercritical carbon dioxide cycle power generation unit through the cold end inlet of the carbon dioxide cycle, is cooled by the cooler 10 and compressed by the first compressor 6, and is sequentially heated through the low-temperature regenerator 5, the high-temperature regenerator 3 and the third heater 4, and enters the turbine 2 from the inlet, to complete the generation cycle. 1934713 of 23 16 / 22 Supercritical carbon dioxide energy. A cooling medium in the chiller is, for example, cooling water.

[0033] In one implementation of this disclosure, the supercritical carbon dioxide cycle power generation unit further includes a three-way diverter control valve 7, a three-way mixing control valve 9, and a second compressor 8. An inlet of the three-way diverter control valve 7 is in communication with the exothermic side outlet of the low-temperature regenerator 5. A first outlet of the three-way diverter control valve 7 forms the cold end outlet of the carbon dioxide cycle, and a second outlet of the three-way diverter control valve 7 is in communication with an inlet of the second compressor 8. An outlet of the second compressor 8 is in communication with a first inlet of the three-way mixing control valve 9, and a second inlet of the three-way mixing control valve 9 is in communication with an endothermic side outlet of the low-temperature regenerator 5.One outlet of the three-way mixing control valve 9 is connected to an endothermic side inlet of the high-temperature regenerator 3. In one implementation, the opening degree of the adjustable three-way diverter control valve 7 can be regulated according to the power supply requirement of the brine lithium extraction unit, thereby regulating the carbon dioxide flow used in the brine lithium extraction unit. Furthermore, the carbon dioxide flow used in the brine lithium extraction system can be regulated by adjusting the opening degree of the three-way mixing control valve 9, thus regulating the power supply to the brine lithium extraction system.

[0034] To make the thermal energy of the supercritical carbon dioxide cycle power generation unit match the thermal energy of the unit of 1934713 of 23 17 / 22 Lithium extraction from brine, in one implementation, the net power of the supercritical carbon dioxide cycle power generation unit is 2 kW to 5 kW in response to the production of 1 tonne of lithium carbonate from lithium extraction from brine.

[0035] In an implementation of this disclosure, as shown in FIG. 1, the supercritical carbon dioxide cycle power generation unit includes an electric generator 1, the electric generator 1 is coaxially connected to a turbine 2, one outlet of the turbine 2 is connected to an exothermic side inlet of a high-temperature regenerator 3, one exothermic side outlet of the high-temperature regenerator 3 is connected to an exothermic side inlet of a low-temperature regenerator 5, one exothermic side outlet of the low-temperature regenerator 5 is connected to a three-way diverter control valve 7 with two outlets, a second outlet thereof is connected to a second compressor 8, one outlet of the second compressor 8 is connected to a three-way mixing control valve 9,a first outlet of the three-way diverter control valve 7 as a cold carbon dioxide cycle the end outlet is connected to an exothermic side inlet of a first heater 14, an exothermic side outlet of the first heater 14 is connected to an exothermic side inlet of a second heater 16, an exothermic side outlet of the second heater 16 is connected to an exothermic side inlet of a generator 19 of an absorption heat pump, an exothermic side outlet of the generator 19 is connected to an exothermic side inlet of a chiller 10 as the cold end inlet of the carbon dioxide cycle, an exothermic side outlet of the chiller 10 is connected to an inlet of a first compressor 6, an outlet of the first compressor 6 is connected to an endothermic side inlet of the low-temperature regenerator 5, and a working substance of, 1934713 of 23 18 / 22 An endothermic side outlet from the low-temperature regenerator 5 enters the three-way mixing control valve 9 to rejoin the working fluid from the three-way diverter control valve 7 and the second compressor 8. The combined working fluid enters the high-temperature regenerator 3 from an endothermic side inlet. An endothermic side outlet from the high-temperature regenerator 3 is connected to an endothermic side inlet of a third heater 4, and an outlet from the third heater 4 is connected to an inlet of the turbine 2, completing the loop of the supercritical carbon dioxide cycle power generation subsystem. The carbon dioxide working fluid at an inlet of the second compressor 8 operates at a pressure of 7.5 MPa to 8.5 MPa and a temperature of 32°C to 40°C, ensuring that the carbon dioxide working fluid operates under supercritical conditions.

[0036] The brine lithium extraction unit includes a filter 27. The brine raw material is first filtered through the filter, the brine permeate from the filter enters a desorber 26 of the absorption heat pump from an endothermic side inlet, the brine permeate from an endothermic side outlet of the desorber 26 enters a condenser 20 from an endothermic side inlet, the brine permeate from an endothermic side outlet of the condenser 20 enters an adsorption tower 11 from a brine inlet for adsorption, and then an adsorbent is washed with water to obtain a desorption liquid.The desorption liquid enters a nanofiltration membrane section 12 from the adsorption tower 11 for filtration, the filtered liquid from the nanofiltration membrane section 12 enters a preheater 13 from an endothermic side inlet for preheating, the preheated liquid from an endothermic side outlet of the preheater 13 enters the first heater 14 from an endothermic side inlet, and the heated liquid. 1934713 of 23 19 / 22 from an endothermic side outlet of the first heater 14 enters a gas-liquid separator 15 from an inlet, to be separated into steam and concentrated brine. Steam from an outlet above the gas-liquid separator is pumped as a heat source to an exothermic side inlet of the preheater 13 to preheat the brine therein. Concentrated brine from an outlet below the gas-liquid separator is pumped to an endothermic side inlet of the second heater 16 to be preheated, along with sodium carbonate solution from a sodium carbonate solution tank 17, to 70°C to 90°C in the second heater 16. The brine and sodium carbonate solution from an endothermic side outlet of the second heater 16 enter a lithium precipitation reactor 18 for the lithium precipitation reaction.

[0037] The supercritical carbon dioxide cycle power generation and brine lithium extraction coupling system of this disclosure has the following advantages:

[0038] 1) Compared to a separate supercritical carbon dioxide cycle, the consumption of cooling water used in power generation from the supercritical carbon dioxide cycle in the coupling cycle is reduced by 50 to 80%.

[0039] 2) The consumption of steam originally required for the concentration of brine evaporation is completely avoided, thus avoiding energy consumption and investment in steam production equipment.

[0040] 3) The temperature of the solution entering the lithium precipitation reactor increases from 20°C to 40°C, which can increase the yield of lithium precipitation by 5% to 20% and can increase the purity of the lithium carbonate obtained by 3% to 7%.

[0041] 4) The temperature of the brine in the adsorption section before entering 1934713 of 23 20 / 22 The adsorption tower increases between 40°C and 50°C, which can increase the adsorption capacity of the adsorbent by 60% to 100% and can increase the yield per unit time of the qualified lithium carbonate-rich liquid by 50% to 120%.

[0042] The total amount of available thermal energy is increased by improving the quality rather than the quantity through the use of the absorption heat pump in the coupling system, thereby achieving a better energy level in the brine heating process with the carbon dioxide working fluid. The supercritical carbon dioxide working fluid from the cold end outlet of the carbon dioxide cycle operates at a temperature between 180°C and 220°C, which is suitable for use as a heating medium to raise and maintain the temperature during lithium precipitation and adsorption in the lithium extraction system from the brine.After heat exchange in the lithium extraction system from brine, the working fluid of the supercritical carbon dioxide cycle in generator 19 releases heat from a temperature ranging from 120°C to 150°C to a temperature ranging from 50°C to 70°C. The temperature of the brine, passing through desorber 26 and condenser 20, increases by 30°C to 60°C. The coefficient of performance (COP) of the absorption heat pump is between 1.8 and 2.5. The system's operation is flexible. The heat output of the absorption heat pump can be adjusted by changing the flow rate of the working fluid in the absorption heat pump cycle.

[0043] Implementations of this disclosure are described in detail above, but this disclosure is not limited to the details of the above implementations. Various simple variations may be made to the technical solutions in this disclosure within the scope of the technical idea of ​​this disclosure, and such simple variations will all be within the scope of protection of this disclosure. 1934713 of 23 21 / 22

[0044] It should also be noted that the technical features described in the previous implementations can be combined in any suitable way without conflict. To avoid unnecessary repetition, this description does not include several possible combinations.

[0045] Furthermore, different implementations of this disclosure may also be arbitrarily combined without departing from the idea of ​​this disclosure, and these combinations will still be considered as content disclosed in this disclosure. 1934713 of 23 22 / 22 1934713 of 23 DANIEL ALEJANDRO GUASCONI - 20184128102 Digitally signed by PORTALTRAM ITES - INPI Date: 2022.08.26 11:18:26 -03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 1934713

Claims

1. A system for coupling a supercritical carbon dioxide power generation cycle and lithium extraction from brine, characterized in that the method comprises an absorption heat pump unit, a supercritical carbon dioxide cycle power generation unit, and a unit for lithium extraction from brine, wherein: the absorption heat pump unit comprises a driving heat source inlet, a driving heat source outlet, a material to be heated inlet, and a heated material outlet; the unit for lithium extraction from brine comprises a brine inlet and a lithium extraction device, and the lithium extraction device has a raw material inlet, a heating medium inlet, and a heating medium outlet;The brine inlet is in communication with the material to be heated inlet of the absorption heat pump unit, and the heated material outlet of the absorption heat pump unit is in communication with the raw material inlet of the lithium extraction device; the supercritical carbon dioxide cycle power generation unit comprises a carbon dioxide cycle cold end outlet and a carbon dioxide cycle cold end inlet;and the cold end outlet of the carbon dioxide cycle is in communication with the heating medium inlet of the unit for lithium extraction from brine and / or the driving heat source inlet of the absorption heat pump unit, and the cold end inlet of the carbon dioxide cycle of the supercritical carbon dioxide cycle power generation unit is in communication with the heating medium outlet of the unit for lithium extraction from brine and / or the driving heat source outlet. See 9 Claims;