A transcritical carbon dioxide energy storage system and method integrating amino energy storage refrigeration

Abstract

The present invention discloses a transcritical carbon dioxide energy storage system and method integrated with amino energy storage and refrigeration. The system comprises an amino energy storage unit, a thermochemical energy storage unit, an ammonia refrigeration unit and a transcritical carbon dioxide energy storage unit; the amino energy storage unit comprises a solar collector, a liquid ammonia storage tank, a nitrogen and hydrogen storage tank and an air separator which are connected in sequence; the thermochemical energy storage unit comprises a methanol-water mixed solution preheater and a methanol steam reforming hydrogen production reactor; the ammonia refrigeration unit comprises a condenser, a first throttle valve, an evaporator and a cooler; the amino energy storage and ammonia refrigeration technology is coupled with the thermochemical energy storage technology, the generated nitrogen and hydrogen are stored for refrigeration to provide cold capacity, and the generated carbon dioxide is used for molten salt heat storage and transcritical carbon dioxide energy storage power generation, thereby achieving refrigeration and power supply without relying on external electricity; the carbon dioxide generated by the reaction is utilized multiple times, thereby greatly improving the energy storage density and efficiency of the system.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage technology, and in particular relates to a transcritical carbon dioxide energy storage system and method integrated with amino energy storage refrigeration. Background Art

[0002] Traditional thermal power generating units that rely on coal-fired power generation will gradually be shut down or rectified, and new energy power plants relying on renewable energy such as solar energy and wind energy will be built. In this process, there may be problems in some areas where the power supply cannot meet the demand, resulting in large-scale power outages in the area, which greatly affects local production and life.

[0003] Due to local natural conditions, some regions, despite possessing certain renewable resources, are unable to achieve large-scale renewable energy generation. In the process of rapid regional economic development, local thermal power generation alone cannot meet the power supply needs, and power transmission from major power-producing provinces is required. Therefore, these areas are extremely susceptible to power supply fluctuations and may cause power shortages. Currently, energy storage technology is the best way to solve this problem. Transcritical carbon dioxide energy storage systems use surplus electricity to compress carbon dioxide to a supercritical state for storage, and when there is a demand for electricity, the stored super-pressurized carbon dioxide is passed through an expander to generate power.

[0004] Some of these regions have a thriving pharmaceutical industry and produce abundant perishable products like seafood and fruit. However, the high temperatures year-round make storing these products difficult, necessitating cold storage to ensure their safety. Traditional cold storage relies primarily on electricity for refrigeration, and frequent power shortages can severely impact its operation. Therefore, there is an urgent need for cold storage with energy storage systems that are independent of electricity or have low power requirements to address power shortages and meet cooling needs. Summary of the Invention

[0005] To address the problem of power shortages in some areas due to power supply fluctuations, which can affect the normal operation of cold storage, this paper combines amino energy storage and refrigeration technologies, thermochemical energy storage technologies, and transcritical carbon dioxide energy storage technologies to provide a transcritical carbon dioxide energy storage system with integrated amino energy storage and refrigeration. By combining amino energy storage technology with the methanol steam reforming reaction, the reaction products are used for both refrigeration and power supply. This system can meet the cooling and power needs of cold storage even during power fluctuations or shortages.

[0006] The present invention is achieved through the following technical solutions: a transcritical carbon dioxide energy storage system integrated with amino energy storage and refrigeration, comprising an amino energy storage unit, a thermochemical energy storage unit, an ammonia refrigeration unit, and a transcritical carbon dioxide energy storage unit; the amino energy storage unit comprises a liquid ammonia storage tank, a precooler, a nitrogen and hydrogen storage tank, and an air separator connected in sequence;

[0007] The ammonia refrigeration unit includes a condenser, an evaporator, a first throttle valve, a first cooler, and a second throttle valve connected in sequence, and the second throttle valve is connected to the liquid ammonia storage tank; the thermochemical energy storage unit includes a methanol-water mixed solution preheater, a methanol steam reforming hydrogen production reactor, a molten salt heat accumulator, an expander, and a second cooler connected in sequence, and the water side of the precooler is connected in sequence to the condenser and the cold water side of the methanol-water mixed solution preheater;

[0008] The hydrogen outlet of the methanol steam reforming hydrogen production reactor is connected to the nitrogen and hydrogen storage tanks, and the carbon dioxide outlet of the methanol steam reforming hydrogen production reactor is connected to the preheater; the gas outlet of the nitrogen and hydrogen storage tanks is connected to the preheater and the ammonia production reactor in sequence; the carbon dioxide outlet of the ammonia production reactor is connected to the molten salt heat accumulator, the expander, the second cooler, the heat accumulator and the liquid carbon dioxide storage tank in sequence, and the ammonia outlet of the ammonia production reactor is connected to the condenser; the inlet and outlet of the heating pipe in the methanol steam reforming hydrogen production reactor are connected to the working medium inlet and outlet of the solar collector;

[0009] The cold water side of the methanol-water mixed solution preheater is connected to the transcritical carbon dioxide energy storage unit; the inlet and outlet of the reaction layer heating medium in the liquid ammonia storage tank are connected to the working fluid inlet and outlet of the solar collector.

[0010] The transcritical carbon dioxide energy storage unit includes a liquid carbon dioxide storage tank, a first compressor, a first intercooler, a second compressor, a second intercooler, a supercritical carbon dioxide storage tank, a first reheater, a first expander, a second reheater, a second expander and a third cooler connected in sequence. The outlet of the third cooler is connected to the hot side of the heat accumulator and the inlet of the liquid carbon dioxide storage tank in sequence, and the outlet of the liquid carbon dioxide storage tank is connected to the cold side of the heat accumulator; the methanol-water mixed solution preheater is connected to the cold water tank, the outlet of the cold water tank is respectively connected to the cold sides of the first intercooler and the second intercooler, the cold sides of the first intercooler and the second intercooler are connected to the hot water tank, the outlet of the hot water tank is respectively connected to the hot sides of the first reheater and the second reheater, and the hot side outlets of the first reheater and the second reheater are connected to the cold water tank.

[0011] Nitrogen and hydrogen storage tanks are divided into nitrogen sub-storage tanks and hydrogen sub-storage tanks, among which the hydrogen sub-storage tanks use fiber-wound metal lining composite materials.

[0012] A high-temperature molten salt heating tube is provided in the molten salt heat accumulator. The high-temperature molten salt heating tube is filled with thermal oil. The thermal oil inlet and outlet of the high-temperature molten salt heating tube are connected to the thermal oil inlet and outlet of the methanol steam reforming hydrogen production reactor. Hitec salt is selected as the molten salt, and the operating temperature range is 142°C to 535°C. SiO2 powder is added to the Hitec salt.

[0013] The ammonia production reactor includes a heat exchange loop, a reactor shell, an outlet heat exchanger and an inlet heat exchanger; the reactor shell has three layers, from the outside to the inside: a stainless steel outer shell, a heat insulation layer and a heat conduction layer, the heat insulation layer is made of silicon aerogel, and the heat conduction layer is made of quartz; the cold side of the outlet heat exchanger is connected to the hot side of the inlet heat exchanger and air is introduced; the solar collector is connected to the heat conduction layer; the inlet and outlet of the heat exchange loop are connected to the preheater and the molten salt heat accumulator respectively.

[0014] The molten salt heat accumulator includes a high-temperature molten salt tubular heat exchanger on the oil side, a high-temperature molten salt tank outlet pump, a low-temperature molten salt storage tank, a high-temperature molten salt storage tank, a low-temperature molten salt storage tank outlet pump and a high-temperature molten salt tubular heat exchanger on the carbon dioxide side; the outlet inlets of the high-temperature molten salt storage tank and the low-temperature molten salt storage tank are respectively connected to the high-temperature molten salt tubular heat exchanger on the oil side and the high-temperature molten salt tubular heat exchanger on the carbon dioxide side, and molten salt pumps are respectively provided at the outlets of the high-temperature molten salt storage tank and the low-temperature molten salt storage tank; carbon dioxide enters the hot side of the high-temperature molten salt tubular heat exchanger on the carbon dioxide side, and the heat transfer oil enters the cold side of the high-temperature molten salt tubular heat exchanger on the oil side.

[0015] The liquid ammonia storage tank is divided into an ammonia storage layer and a reaction layer. The reaction layer uses iron catalyst as a catalyst; the reaction layer uses the working fluid in the solar collector as the heating medium.

[0016] The transcritical carbon dioxide energy storage system with integrated amino energy storage and refrigeration of the present invention is characterized in that, during initial operation, a solar collector heats the ammonia production reactor to a reaction temperature and pauses heating to maintain the temperature inside the ammonia production reactor; a methanol steam reforming hydrogen production reactor is preheated to a set temperature, and a methanol-water mixed solution passes through a methanol-water mixed solution preheater and enters the methanol steam reforming hydrogen production reactor, where methanol and water generate carbon dioxide and hydrogen under the conditions of the set temperature and the presence of a catalyst; air enters an air separator, and the separated nitrogen enters a nitrogen and hydrogen storage tank for storage;

[0017] During the energy storage phase, when there is sufficient sunshine or electricity supply, the reaction layer in the liquid ammonia storage tank is heated to its reaction temperature. Under the action of the reaction temperature and the catalyst, the liquid ammonia is decomposed into nitrogen and hydrogen and discharged. The nitrogen and hydrogen are pre-cooled with cold water in the precooler and then enter the nitrogen and hydrogen storage tanks for storage respectively. The hydrogen generated by the methanol steam reforming hydrogen production reactor enters the nitrogen and hydrogen storage tanks for storage, and the carbon dioxide generated by the reaction is preheated in the preheater and flows from the nitrogen and hydrogen storage tanks to the ammonia production reactor. The carbon dioxide then enters the ammonia production reactor to absorb a large amount of heat released by the ammonia production reaction and turns into high-temperature carbon dioxide. The high-temperature carbon dioxide heats the low-temperature molten salt on the carbon dioxide side of the molten salt heat accumulator to form high-temperature molten salt and is stored.

[0018] The liquid carbon dioxide in the liquid carbon dioxide storage tank absorbs heat and vaporizes through the heat accumulator, and then enters the transcritical carbon dioxide energy storage unit for energy storage and release;

[0019] During the energy release phase, when sunshine is insufficient or the power supply fluctuates, the nitrogen and hydrogen in the nitrogen and hydrogen storage tanks are preheated in the preheater and then enter the ammonia production reactor. In the ammonia production reactor, the nitrogen and hydrogen are subjected to the combined effects of high temperature, high pressure and catalyst to generate ammonia, which enters the condenser and releases a large amount of heat. The ammonia is cooled and reduced in pressure to become liquid in the first throttle valve, and then absorbs heat in the evaporator to produce a refrigeration effect. The ammonia discharged from the evaporator is cooled and reduced in pressure to liquid ammonia in the first cooler and the second throttle valve and stored in the liquid ammonia storage tank. The high-temperature medium in the molten salt heat accumulator provides heat for the hydrogen production reaction of the methanol steam reforming hydrogen production reactor. The carbon dioxide after heat release enters the transcritical carbon dioxide energy storage unit for energy storage and releases energy, and then releases heat and cools to become liquid and is stored in the liquid carbon dioxide storage tank.

[0020] When the heating medium flowing out of the molten salt heat accumulator enters the heating pipe of the methanol steam reforming hydrogen production reactor, the solar thermal collector stops heating the methanol steam reforming hydrogen production reactor.

[0021] The cold water first exchanges heat in the precooler and the first cooler, then absorbs a large amount of heat released in the condenser. After the temperature rises, the methanol-water mixed solution input into the system is preheated in the methanol-water mixed solution preheater, and then re-enters the cold water tank for storage, forming a cycle; the solar collector continuously supplies heat to the methanol steam reforming hydrogen production reactor and the ammonia production reactor.

[0022] Based on the transcritical carbon dioxide energy storage unit, carbon dioxide is compressed to a supercritical state in the first compressor and the second compressor in succession, and enters the supercritical carbon dioxide storage tank for storage. The compression heat is released to the cold water transported from the cold water tank through the first intercooler and the second intercooler, and then stored in the hot water tank; the supercritical carbon dioxide in the supercritical carbon dioxide storage tank is reduced in pressure to the energy release pressure through the third throttle valve, and then enters the expansion unit, is heated in the first reheater, and then enters the first expander to perform work and generate electricity. The carbon dioxide discharged from the first expander is heated in the second reheater and then enters the second expander to perform work and generate electricity; the carbon dioxide discharged from the second expander is first cooled by the third cooler, cooled to a liquid state in the heat accumulator, and then enters the liquid carbon dioxide storage tank for storage; the hot water in the hot water tank is cooled in the first reheater and the second reheater, and the temperature is reduced and stored in the cold water tank.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] The present invention couples ammonia energy storage technology with thermochemical energy storage technology to store generated nitrogen and hydrogen, and synthesize ammonia in the energy release step for refrigeration and cold supply. The generated carbon dioxide is used for molten salt heat storage and transcritical carbon dioxide energy storage power generation, achieving simultaneous refrigeration and power supply without relying on external power input. After the solar collector provides the initial reaction temperature, the large amount of heat released in the ammonia production reactor is used to heat the carbon dioxide from the methanol steam reforming hydrogen production reactor. The heat of the high-temperature carbon dioxide is stored in the molten salt and reused in the transcritical carbon dioxide energy storage unit, achieving self-sufficiency and independent of external power supply. The molten salt heat accumulator not only meets the needs of heat storage, but also replaces the carbon dioxide gas with poor heat exchange effect with high-temperature heat transfer oil to provide heat for the hydrogen production reaction, greatly improving the energy storage density and efficiency of the system. The carbon dioxide generated by the reforming enters the liquid carbon dioxide storage tank after energy release through the expander, increasing the amount of carbon dioxide in the transcritical carbon dioxide energy storage module. The energy storage scale can also be adjusted as needed. The combination of ammonia energy storage technology and ammonia refrigeration technology generates a large amount of cold and realizes the circulation of ammonia.

[0025] Furthermore, the ammonia production reactor uses a three-layer shell to achieve initial heating and insulation of the ammonia production reaction. Nitrogen, hydrogen and ammonia are preheated and cooled respectively through heat exchange in the heat exchange loop and inlet and outlet heat exchangers, greatly improving the heat exchange efficiency and system efficiency.

[0026] Furthermore, a cold water circulation is formed in the precooler, the first cooler, the condenser, the methanol-water mixed solution preheater and the cold water tank, thereby improving the refrigeration efficiency and energy storage efficiency of ammonia through precooling, preheating and cooling.

[0027] Furthermore, the ammonia storage tank, methanol steam reforming hydrogen production reactor and ammonia production reactor are all heated by the working fluid of the solar collector, wherein the solar collector is connected to the heat conductive layer in the ammonia production reactor, and the heat conductive layer can be heated by solar energy, thereby reducing the demand for external electricity and improving the self-circulation capacity of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention provides a transcritical carbon dioxide energy storage system integrating amino energy storage and refrigeration.

[0029] Figure 2 The figure is a schematic diagram of an ammonia production reactor that can be implemented in the present invention.

[0030] Figure 3 This is a schematic diagram of a molten salt heat accumulator that can be implemented in the present invention.

[0031] In the figure: 1. Liquid ammonia storage tank; 2. First valve; 3. Precooler; 4. Nitrogen and hydrogen storage tanks; 5. Second valve; 6. Preheater; 7. Ammonia production reactor; 8. Condenser; 9. First throttle valve; 10. Evaporator; 11. Cooler; 12. Second throttle valve; 13. Solar collector; 14. Methanol steam reforming hydrogen production reactor; 15. Methanol-water mixed solution preheater; 16. First compressor; 17. First intercooler; 18. Second compressor; 19. Second intercooler; 20. Supercritical carbon dioxide storage tank; 21. Third throttle valve; 22. First reheater; 23. First expander; 24. Second reheater; 25. Second expander; 26. Third cooler; 27. Heat accumulator; 28. Liquid carbon dioxide storage tank; 29. ​​Hot water tank; 30. Cold water tank; 31. Molten salt heat accumulator; 32. Third expander; 33. Second cooler; 34. Air separator; 35. Heat conduction layer; 36. Heat insulation layer; 37. Stainless steel shell; 38. Heat exchange loop; 39. Outlet heat exchanger; 40. Inlet heat exchanger; 41. Oil-side high-temperature molten salt tubular heat exchanger; 42. High-temperature molten salt tank outlet pump; 43. Low-temperature molten salt storage tank; 44. High-temperature molten salt storage tank; 45. Low-temperature molten salt storage tank outlet pump; 46. High-temperature molten salt tubular heat exchanger on the carbon dioxide side. DETAILED DESCRIPTION

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

[0033] This invention couples ammonia refrigeration technology with thermochemical energy storage. The generated nitrogen and hydrogen are stored, and ammonia is synthesized during the energy release phase to provide cooling. The generated carbon dioxide is used for molten salt heat storage and transcritical carbon dioxide energy storage power generation. The system achieves both cooling and power generation with virtually no external power input. The carbon dioxide generated by the methanol steam reforming reaction is efficiently reused multiple times, significantly improving the system's energy storage density and efficiency.

[0034] like Figure 1As shown, a transcritical carbon dioxide energy storage system that couples amino energy storage refrigeration with thermochemical energy storage includes an amino energy storage unit, a thermochemical energy storage unit, an ammonia refrigeration unit, and a transcritical carbon dioxide energy storage unit; specifically, it includes a liquid ammonia storage tank 1, a first valve 2, a precooler 3, a nitrogen and hydrogen storage tank 4, a second valve 5, a preheater 6, an ammonia production reactor 7, a condenser 8, a first throttle valve 9, an evaporator 10, a first cooler 11, a second throttle valve 12, a solar collector 13, and a methanol steam reforming hydrogen production reactor. 14, methanol-water mixed solution preheater 15, first compressor 16, first intercooler 17, second compressor 18, second intercooler 19, supercritical carbon dioxide storage tank 20, third throttle valve 21, first reheater 22, first expander 23, second reheater 24, second expander 25, third cooler 26, heat accumulator 27, liquid carbon dioxide storage tank 28, hot water tank 29, cold water tank 30, molten salt heat accumulator 31, third expander 32, second cooler 33, air separator 34;

[0035] The amino energy storage unit includes a liquid ammonia storage tank 1, a nitrogen and hydrogen storage tank 4, and an air separator 34, which are connected in sequence. A first valve 2 and a precooler 3 are sequentially arranged between the liquid ammonia storage tank 1 and the nitrogen and hydrogen storage tank 4. The working fluid inlet and outlet of the solar collector 13 are connected to the inlet and outlet of the liquid ammonia storage tank 1. The liquid ammonia storage tank 1 is divided into an ammonia storage layer and a reaction layer. Iron catalyst is used as a catalyst in the reaction layer. The nitrogen and hydrogen storage tank 4 is divided into a nitrogen sub-storage tank and a hydrogen sub-storage tank.

[0036] The thermochemical energy storage unit includes a methanol-water mixed solution preheater 15, a methanol steam reforming hydrogen production reactor 14, a molten salt heat accumulator 31, a third expander 32, and a second cooler 33, all connected in sequence. A hydrogen transmission pipeline is provided between the methanol steam reforming hydrogen production reactor 14 and the nitrogen and hydrogen storage tank 4, and a carbon dioxide transmission pipeline is provided between the methanol steam reforming hydrogen production reactor 14 and the preheater 6. The hydrogen outlet of the methanol steam reforming hydrogen production reactor 14 is connected to the nitrogen and hydrogen storage tank 4, while the carbon dioxide outlet of the methanol steam reforming hydrogen production reactor 14 is connected to the preheater 6; the outlet of the preheater 6 is connected to the ammonia production reactor 7. Heat exchange tubes are installed within the methanol steam reforming hydrogen production reactor 14 to achieve heating. The inlet and outlet of the heating tubes are connected to the oil side of the molten salt heat accumulator 31, and high-temperature heat transfer oil flows through the tubes. The carbon dioxide inlet of the molten salt accumulator 31 is connected to the ammonia production reactor 7, and the carbon dioxide outlet of the molten salt accumulator 31 is connected to the third expander 32, with carbon dioxide flowing through the pipe; the outlet of the third expander 32 is connected to the second cooler 33, and then connected to the hot side inlet of the accumulator 27 of the transcritical carbon dioxide energy storage unit. The cold side inlet of the accumulator 27 is connected to the outlet of the liquid carbon dioxide storage tank 28, and the hot side outlet of the accumulator 27 is connected. The methanol steam reforming reaction uses a porous honeycomb ceramic matrix coated with a trace amount of lead ZnO coating as a catalyst. The molten salt is selected from Hitec salt (ternary mixed nitrate, KNO3, NaNO2 and NaNO3). Hitec salt has a large specific heat capacity and a temperature range of 142°C to 535°C.

[0037] The ammonia refrigeration unit includes a condenser 8, an evaporator 10, a first throttle valve 9, a first cooler 11, and a second throttle valve 12 connected in sequence, and the second throttle valve 12 is connected to the liquid ammonia storage tank 1; the condenser 8, the first cooler 11 and the precooler 3 are connected by a water pipe, and the condenser 8 is connected to the methanol-water mixed solution preheater 15.

[0038] The transcritical carbon dioxide energy storage unit includes a compressor unit, a supercritical carbon dioxide storage tank 20, an expansion unit, a hot and cold water supply system and a liquid carbon dioxide storage tank 28, wherein the compressor unit includes a first compressor 16, a first intercooler 17, a second compressor 18 and a second intercooler 19, and the expansion unit includes a first expander 23, a first reheater 22, a second reheater 24 and a second expander 25; a third cooler 26 and a heat accumulator 27 are connected between the second expander 25 and the liquid carbon dioxide storage tank 28.

[0039] The cold and hot water supply system includes a cold water tank 30 and a hot water tank 29, which are respectively connected to the first intercooler 17, the second intercooler 19, the first reheater 22 and the second reheater 24 to supply and collect cold and hot water.

[0040] In addition, the cold water tank 30, the methanol-water mixed solution preheater 15, the condenser 8, the first cooler 11 and the precooler 3 form a circulation.

[0041] The solar collector 13 absorbs solar radiation and uses the solar radiation energy to increase the temperature of the high-temperature heat transfer oil in the heat collection pipe. The heated high-temperature heat transfer oil can flow into the liquid ammonia storage tank 1, the ammonia production reactor 7 and the methanol steam reforming hydrogen production reactor 14 respectively, and heat the equipment through the heat exchanger. The high-temperature heat transfer oil that has released the heat flows back to the heat collection pipe to be heated again.

[0042] The hydrogen sub-storage tank in the nitrogen and hydrogen storage tank 4 uses a fiber-wound metal lining composite material to ensure storage safety and prevent hydrogen embrittlement.

[0043] The operating method of the transcritical carbon dioxide energy storage system integrated with amino energy storage refrigeration according to the present invention is as follows:

[0044] During the initial operation, the solar collector 13 is used to heat the ammonia production reactor 7 to 500° C. and then the heating can be suspended. The ammonia production reactor 7 can maintain this temperature inside the reactor; the methanol steam reforming hydrogen production reactor 14 is preheated to 400° C., and the methanol-water mixed solution enters the methanol steam reforming hydrogen production reactor 14 through the methanol-water mixed solution preheater 15, so that methanol and water generate carbon dioxide and hydrogen under the conditions of high temperature and catalyst.

[0045] During the energy storage phase, when there is sufficient sunshine or electricity, the reaction layer in the liquid ammonia storage tank 1 is heated. Under the action of high temperature and catalyst, the liquid ammonia decomposes into nitrogen and hydrogen, which are then discharged through the first valve 2 and pre-cooled by cold water in the pre-cooler 3 before entering the nitrogen and hydrogen sub-storage tanks for storage, respectively. The hydrogen generated in the methanol steam reforming hydrogen production reactor 14 is stored in the hydrogen sub-storage tank. The carbon dioxide generated by the reaction is preheated in the preheater 6, flowing from the nitrogen and hydrogen storage tanks 4 to the ammonia production reactor 7. It then enters the ammonia production reactor 7, where it absorbs the large amount of heat released by the ammonia production reaction and turns into high-temperature carbon dioxide. The high-temperature carbon dioxide heats the low-temperature molten salt on the carbon dioxide side of the molten salt regenerator 31, converting it into high-temperature molten salt for storage.

[0046] The liquid carbon dioxide in the liquid carbon dioxide storage tank 28 absorbs heat and vaporizes through the heat accumulator 27, then enters the compressor unit, is compressed into a supercritical state in the first compressor 16 and the second compressor 18, and is stored in the supercritical carbon dioxide storage tank 20. The compression heat is released to the cold water transported from the cold water tank 30 through the first intercooler 17 and the second intercooler 19, and then stored in the hot water tank 29.

[0047] The air enters the air separator 34, and the separated nitrogen enters the nitrogen and hydrogen storage tank 4 for storage.

[0048] During the energy release phase, when sunlight is insufficient or the power supply fluctuates, the nitrogen and hydrogen in the nitrogen and hydrogen storage tanks 4 pass through the second valve 5 and are preheated by carbon dioxide gas from the methanol steam reforming hydrogen production reactor 14 in the preheater 6 before entering the ammonia production reactor 7. In the ammonia production reactor 7, the nitrogen and hydrogen are subjected to the combined effects of high temperature, high pressure, and the catalyst, producing ammonia gas before being discharged. The discharged ammonia gas releases a large amount of heat in the condenser 8, is cooled and reduced in pressure to a liquid state in the first throttle valve 9, and then absorbs heat in the evaporator 10, generating a cooling effect. The ammonia gas discharged from the evaporator 10 is cooled and reduced in pressure to liquid ammonia in the first cooler 11 and the second throttle valve 12, and is stored in the liquid ammonia storage tank 1. The high-temperature molten salt in the molten salt heat accumulator 31 heats the cold oil stored in the pipes. The heated hot oil enters the methanol steam reforming hydrogen production reactor 14 to provide heat for the hydrogen production reaction. The high-temperature molten salt releases heat and becomes low-temperature molten salt for storage. The cooled cold oil then flows back to the molten salt heat accumulator 31, completing the cycle. The carbon dioxide after releasing heat enters the third expander 32 to expand and generate electricity. The carbon dioxide output from the third expander 32 is first cooled to room temperature by the second cooler 33, then releases heat in the heat accumulator 27 and cools to liquid form, which is then stored in the liquid carbon dioxide storage tank 28.

[0049] When the hot oil flowing out of the molten salt heat accumulator 31 enters the heating pipe of the methanol steam reforming hydrogen production reactor 14, the solar collector 13 can stop heating the methanol steam reforming hydrogen production reactor 14.

[0050] The supercritical carbon dioxide in the supercritical carbon dioxide storage tank 20 is reduced in pressure to the energy release pressure by the third throttle valve 21 before entering the expansion unit. After being heated in the first reheater 22, it enters the first expander 23 to generate power. The carbon dioxide discharged from the first expander 23 is further heated in the second reheater 24 before entering the second expander 25 to generate power. The carbon dioxide discharged from the second expander 25 is first cooled in the third cooler 26, then cooled to a liquid state in the heat accumulator 27 before entering the liquid carbon dioxide storage tank 28 for storage. The hot water in the hot water tank 29 is cooled after heat exchange in the first and second reheaters 22, 24, and is then stored in the cold water tank 30.

[0051] The cold water first exchanges heat in the precooler 3 and the first cooler 11, and then absorbs a large amount of heat released in the condenser 8. After the temperature rises, the methanol-water mixed solution input into the system is preheated in the methanol-water mixed solution preheater 15, and then re-enters the cold water tank 30 for storage, forming a cycle.

[0052] Preferably, as the system operates, the methanol-water mixed solution input into the system will generate carbon dioxide after the hydrogen production reaction and be stored in the liquid carbon dioxide storage tank 28 and the supercritical carbon dioxide storage tank 20. The amount of liquid carbon dioxide and supercritical carbon dioxide will continue to increase. The liquid carbon dioxide storage tank 28 and the supercritical carbon dioxide storage tank 20 can be expanded to form a storage tank module, or liquid carbon dioxide can be output.

[0053] Preferably, if there is sufficient sunshine or electricity supply, the solar collector 13 can continuously supply heat to the methanol steam reforming hydrogen production reactor 14 and the ammonia production reactor 7 to make the reaction more complete.

[0054] As an example, Figure 2 The figure shows a schematic diagram of an ammonia production reactor that can be implemented in the present invention. The ammonia production reactor includes a heat exchange loop 38, a reactor shell, an outlet heat exchanger 39, and an inlet heat exchanger 40. The reactor shell has three layers, which are a stainless steel shell 37, a heat insulation layer 36, and a heat conductive layer 35 from the outside to the inside. The heat insulation layer 36 is made of silicon aerogel, and the heat conductive layer is made of quartz. The ammonia production reaction uses iron-coal as a catalyst. Due to the ammonia production reaction N2+3H2 The 2NH3 reaction is reversible, and under the reaction conditions, the conversion rate of ammonia is relatively low. An outlet heat exchanger 39 is installed on the outlet side to cool the outlet gas with air, shifting the reaction in the positive direction and promoting ammonia production. In addition, an inlet heat exchanger 40 is installed on the inlet side to preheat the nitrogen and hydrogen with the air that has absorbed heat in the outlet heat exchanger 39. Carbon dioxide is introduced into the heat exchange loop 38 to provide internal heating.

[0055] The working medium inlet and outlet of the solar thermal collector 13 are connected to the inlet and outlet of the heat-conducting layer 35 , and the heat-conducting layer 35 can be heated by solar energy. The heat-conducting layer 35 uses quartz radiation heating to provide heat for the reaction.

[0056] As an example of a molten salt heat accumulator, Figure 3As shown, the present invention provides a schematic diagram of an implementable molten salt heat accumulator, including an oil-side high-temperature molten salt tubular heat exchanger 41, a high-temperature molten salt tank outlet pump 42, a low-temperature molten salt storage tank 43, a high-temperature molten salt storage tank 44, a low-temperature molten salt storage tank outlet pump 45 and a carbon dioxide-side high-temperature molten salt tubular heat exchanger 46; the outlet and inlet of the high-temperature molten salt storage tank 44 and the low-temperature molten salt storage tank 43 are respectively connected to the oil-side high-temperature molten salt tubular heat exchanger 41 and the carbon dioxide-side high-temperature molten salt tubular heat exchanger 46, and molten salt pumps are respectively provided at the outlets of the high-temperature molten salt storage tank 44 and the low-temperature molten salt storage tank 43. The molten salt is a ternary mixed nitrate of Hitec salt, KNO3, NaNO2 and NaNO3. Hitec salt has a large specific heat capacity and a temperature range of 142°C to 535°C. SiO2 powder is added to the Hitec salt to enhance the heat transfer performance and chemical stability of the Hitec salt and increase the specific heat capacity. Carbon dioxide enters the hot side of the high-temperature molten salt tubular heat exchanger 46 on the carbon dioxide side, and the heat transfer oil enters the cold side of the high-temperature molten salt tubular heat exchanger 41 on the oil side.

[0057] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A transcritical carbon dioxide energy storage system integrated with amino energy storage refrigeration, characterized in that: It includes an amino energy storage unit, a thermochemical energy storage unit, an ammonia refrigeration unit, and a transcritical carbon dioxide energy storage unit; the amino energy storage unit includes a liquid ammonia storage tank (1), a precooler (3), a nitrogen and hydrogen storage tank (4), and an air separator (34) that are connected in sequence; The ammonia refrigeration unit comprises a condenser (8), an evaporator (10), a first throttle valve (9), a first cooler (11), and a second throttle valve (12) which are connected in sequence, and the second throttle valve (12) is connected to the liquid ammonia storage tank (1); the thermochemical energy storage unit comprises a methanol-water mixed solution preheater (15), a methanol steam reforming hydrogen production reactor (14), a molten salt heat accumulator (31), an expander, and a second cooler (33) which are connected in sequence, and the water side of the precooler (3) is connected in sequence to the condenser (8) and the cold water side of the methanol-water mixed solution preheater (15); The hydrogen outlet of the methanol steam reforming hydrogen production reactor (14) is connected to the nitrogen and hydrogen storage tank (4), and the carbon dioxide outlet of the methanol steam reforming hydrogen production reactor (14) is connected to the preheater (6); the gas outlet of the nitrogen and hydrogen storage tank (4) is connected to the preheater (6) and the ammonia production reactor (7) in sequence; the carbon dioxide outlet of the ammonia production reactor (7) is connected to the molten salt heat accumulator (31), the expander, the second cooler (33), the heat accumulator (27) and the liquid carbon dioxide storage tank (28) in sequence, and the ammonia outlet of the ammonia production reactor (7) is connected to the condenser (8); the inlet and outlet of the heating pipe in the methanol steam reforming hydrogen production reactor (14) are connected to the working medium inlet and outlet of the solar collector (13); The cold water side of the methanol-water mixed solution preheater (15) is connected to the transcritical carbon dioxide energy storage unit; the inlet and outlet of the reaction layer heating medium in the liquid ammonia storage tank (1) are connected to the working medium inlet and outlet of the solar collector (13).

2. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: The transcritical carbon dioxide energy storage unit comprises a liquid carbon dioxide storage tank (28), a first compressor (16), a first intercooler (17), a second compressor (18), a second intercooler (19), a supercritical carbon dioxide storage tank (20), a first reheater (22), a first expander (23), a second reheater (24), a second expander (25) and a third cooler (26) connected in sequence, wherein the outlet of the third cooler (26) is connected in sequence to the hot side of the heat accumulator (27) and the inlet of the liquid carbon dioxide storage tank (28). The outlet of (28) is connected to the cold side of the heat accumulator (27); the methanol-water mixed solution preheater (15) is connected to the cold water tank (30), the outlet of the cold water tank (30) is respectively connected to the cold sides of the first intercooler (17) and the second intercooler (19), the cold sides of the first intercooler (17) and the second intercooler (19) are connected to the hot water tank (29), the outlet of the hot water tank (29) is respectively connected to the hot sides of the first reheater (22) and the second reheater (24), and the hot side outlets of the first reheater (22) and the second reheater (24) are connected to the cold water tank (30).

3. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: The nitrogen and hydrogen storage tank (4) is divided into a nitrogen sub-storage tank and a hydrogen sub-storage tank, wherein the hydrogen sub-storage tank uses a fiber-wound metal lining composite material.

4. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: A high-temperature molten salt heating tube is provided in the molten salt heat accumulator (31), the high-temperature molten salt heating tube is filled with heat transfer oil, and the heat transfer oil inlet and outlet of the high-temperature molten salt heating tube are connected to the heat transfer oil inlet and outlet of the methanol steam reforming hydrogen production reactor (14); Hitec salt is selected as the molten salt, and the operating temperature range is 142°C to 535°C; SiO2 powder is added to the Hitec salt.

5. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: The ammonia production reactor (7) includes a heat exchange loop (38), a reactor shell, an outlet heat exchanger (39) and an inlet heat exchanger (40); the reactor shell has three layers, which are, from the outside to the inside, a stainless steel outer shell (37), a heat insulation layer (36) and a heat conductive layer (35), wherein the heat insulation layer (36) is made of silicon aerogel and the heat conductive layer (35) is made of quartz; the cold side of the outlet heat exchanger (39) is connected to the hot side of the inlet heat exchanger (40) and air is introduced into the cold side; the solar collector (13) is connected to the heat conductive layer (35); the inlet and outlet of the heat exchange loop (38) are respectively connected to the preheater (6) and the molten salt heat accumulator (31).

6. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: The molten salt heat accumulator comprises an oil-side high-temperature molten salt tubular heat exchanger (41), a high-temperature molten salt tank outlet pump (42), a low-temperature molten salt storage tank (43), a high-temperature molten salt storage tank (44), a low-temperature molten salt storage tank outlet pump (45) and a carbon dioxide-side high-temperature molten salt tubular heat exchanger (46); the inlets and outlets of the high-temperature molten salt storage tank (44) and the low-temperature molten salt storage tank (43) are respectively connected to the oil-side high-temperature molten salt tubular heat exchanger (41) and the carbon dioxide-side high-temperature molten salt tubular heat exchanger (46), and molten salt pumps are respectively provided at the outlets of the high-temperature molten salt storage tank (44) and the low-temperature molten salt storage tank (43); carbon dioxide enters the hot side of the carbon dioxide-side high-temperature molten salt tubular heat exchanger (46), and heat transfer oil enters the cold side of the oil-side high-temperature molten salt tubular heat exchanger (41).

7. The transcritical carbon dioxide energy storage system with integrated amino energy storage refrigeration according to claim 1 is characterized in that: The liquid ammonia storage tank (1) is divided into an ammonia storage layer and a reaction layer. The reaction layer uses an iron catalyst as a catalyst; the reaction layer uses the working fluid in the solar collector (13) as a heating medium.

8. The method for operating the transcritical carbon dioxide energy storage system integrated with amino energy storage refrigeration according to any one of claims 1 to 7, characterized in that: During the initial operation, the solar collector (13) heats the ammonia production reactor (7) to the reaction temperature and stops heating, and the ammonia production reactor (7) maintains the temperature inside the reactor; the methanol steam reforming hydrogen production reactor (14) is preheated to a set temperature, and the methanol-water mixed solution enters the methanol steam reforming hydrogen production reactor (14) through the methanol-water mixed solution preheater (15), so that methanol and water generate carbon dioxide and hydrogen under the conditions of the set temperature and the catalyst; The air enters the air separator (34), and the separated nitrogen enters the nitrogen and hydrogen storage tank (4) for storage; In the energy storage stage, when there is sufficient sunshine or electricity supply, the reaction layer in the liquid ammonia storage tank (1) is heated to its reaction temperature. Under the action of the reaction temperature and the catalyst, the liquid ammonia is decomposed into nitrogen and hydrogen and discharged. The nitrogen and hydrogen are pre-cooled by cold water in the pre-cooler (3) and then enter the nitrogen and hydrogen storage tanks (4) for storage; the hydrogen generated by the methanol steam reforming hydrogen production reactor (14) enters the nitrogen and hydrogen storage tanks (4) for storage, and the carbon dioxide generated by the reaction is preheated in the preheater (6) and flows from the nitrogen and hydrogen storage tanks (4) to the ammonia production reactor (7). The carbon dioxide then enters the ammonia production reactor (7) to absorb a large amount of heat released by the ammonia production reaction and turns into high-temperature carbon dioxide. The high-temperature carbon dioxide heats the low-temperature molten salt to high-temperature molten salt on the carbon dioxide side of the molten salt heat accumulator (31) and is stored; The liquid carbon dioxide in the liquid carbon dioxide storage tank (28) absorbs heat and vaporizes through the heat accumulator (27), and then enters the transcritical carbon dioxide energy storage unit for energy storage and release; During the energy release phase, when sunshine is insufficient or power supply fluctuates, the nitrogen and hydrogen in the nitrogen and hydrogen storage tanks (4) are preheated in the preheater (6) and then enter the ammonia production reactor (7). The nitrogen and hydrogen are subjected to the combined action of high temperature, high pressure and catalyst in the ammonia production reactor (7) to generate ammonia, which then enters the condenser (8) and releases a large amount of heat. The ammonia is cooled and reduced in pressure in the first throttle valve (9) to become a liquid, and then absorbs heat in the evaporator (10) to produce a refrigeration effect. The ammonia discharged from the evaporator (10) is cooled and reduced in pressure in the first cooler (11) and the second throttle valve (12) to become liquid ammonia and is stored in the liquid ammonia storage tank (1). The high-temperature medium in the molten salt heat accumulator (31) provides heat for the hydrogen production reaction of the methanol steam reforming hydrogen production reactor (14). The carbon dioxide after releasing heat enters the transcritical carbon dioxide energy storage unit to store energy, releases energy, and then releases heat and cools to become a liquid and is stored in the liquid carbon dioxide storage tank (28). When the heating medium flowing out of the molten salt heat accumulator (31) enters the heating pipe of the methanol steam reforming hydrogen production reactor (14), the solar collector (13) stops heating the methanol steam reforming hydrogen production reactor (14).

9. The method for operating the transcritical carbon dioxide energy storage system integrated with amino energy storage refrigeration according to claim 8, characterized in that: The cold water first exchanges heat in the precooler (3) and the first cooler (11), and then absorbs a large amount of heat released in the condenser (8). After the temperature rises, the methanol-water mixed solution input into the system is preheated in the methanol-water mixed solution preheater (15), and then re-enters the cold water tank (30) for storage, forming a cycle; and the solar collector (13) continuously supplies heat to the methanol steam reforming hydrogen production reactor (14) and the ammonia production reactor (7).

10. The method for operating the transcritical carbon dioxide energy storage system integrated with amino energy storage refrigeration according to claim 8, characterized in that: Based on the transcritical carbon dioxide energy storage unit, carbon dioxide is compressed into a supercritical state in the first compressor (16) and the second compressor (18), and then enters the supercritical carbon dioxide storage tank (20) for storage. The compression heat is released to the cold water transported from the cold water tank (30) through the first intercooler (17) and the second intercooler (19), and then stored in the hot water tank (29); the supercritical carbon dioxide in the supercritical carbon dioxide storage tank (20) is reduced in pressure to the energy release pressure through the third throttle valve (21), and then enters the expansion unit and is heated in the first reheater (22). After being heated, the carbon dioxide enters the first expander (23) to generate power. The carbon dioxide discharged from the first expander (23) is heated in the second reheater (24) and then enters the second expander (25) to generate power. The carbon dioxide discharged from the second expander (25) is first cooled by the third cooler (26), cooled to liquid in the heat accumulator (27), and then enters the liquid carbon dioxide storage tank (28) for storage. The hot water in the hot water tank (29) is cooled by heat exchange in the first reheater (22) and the second reheater (24), and the temperature is reduced and the hot water is stored in the cold water tank (30).

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