Green ammonia synthesis system

Abstract

The invention relates to the technical field of renewable energy sources, and discloses a green ammonia synthesis system which is characterized in that photo-thermal equipment is used for heating a heat storage medium by utilizing photo-thermal conversion; the steam generator receives the heated heat storage medium, heats the water medium and generates steam; the turbine receives steam to do work; the generator generates electricity along with the steam turbine; the second heat storage structure receives the cooled heat storage medium; the air compression, liquefaction and separation subsystem is used for liquefying air into liquid air and separating the liquid air into liquid oxygen and liquid nitrogen; the first heat exchanger receives the cooled heat storage medium and heats liquid air into gaseous air; the second heat exchanger receives the cooled heat storage medium and heats liquid nitrogen into nitrogen; the water electrolysis subsystem is used for decomposing water into hydrogen and oxygen; the green ammonia synthesis subsystem receives the nitrogen and the hydrogen and synthesizes the nitrogen and the hydrogen into ammonia gas. Sunlight is converted into electric energy to drive the green ammonia synthesis system to operate, the heat storage medium directly provides heat energy for liquid air and liquid nitrogen, repeated energy conversion loss is avoided, and the utilization efficiency of solar energy is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of renewable energy, and in particular to a green ammonia synthesis system. Background Art

[0002] With the increasing depletion of traditional non-renewable energy and the pollution it causes to the environment, the development of renewable green energy has become a focus in the energy field.

[0003] Since ammonia has many advantages such as high energy density, easy liquefaction, convenient storage and transportation, and no pollution; and there is no carbon emission in the process of synthesizing ammonia, the synthesis of ammonia has become a hot spot for the development of domestic new energy. In addition, as one of the most important chemical raw materials, ammonia is widely used and in great demand in many fields such as chemical industry, agriculture and industry in addition to its application in the energy field. Accelerating the development of synthetic ammonia production technology, especially the use of solar thermal technology to produce ammonia, also known as green ammonia synthesis, has become a strategic choice for my country to respond to global climate change, ensure national energy supply security and achieve high-quality industrial development.

[0004] Solar thermal technology is a technology that captures and absorbs solar radiation and converts it into heat for utilization. It has the advantages of being green, environmentally friendly and pollution-free. However, due to the intermittent volatility of solar energy, the energy output of the sun not only varies with time of day, but is also affected by factors such as season, illumination and weather; however, the synthesis of ammonia is a continuous production process. Therefore, the intermittent volatility of solar energy is not compatible with the continuous synthesis of green ammonia.

[0005] After continuous research and development, solar thermal technology can be coupled with the process of synthetic ammonia production. Specifically, thermal energy is converted into kinetic energy of the steam turbine through steam medium to do work, drive the generator to generate electricity, and then use the generated electricity for liquefied air, air separation nitrogen production, water electrolysis hydrogen production and green ammonia synthesis production. In the entire production process mentioned above, almost no carbon emissions are generated, and because solar energy is converted into thermal energy and then into electrical energy for power generation, the smooth output of electricity can be guaranteed, overcoming the mismatch between the intermittent volatility of solar energy and the continuous synthesis of green ammonia, which plays a positive role in accelerating the green and low-carbon transformation of energy and promoting the construction of ecological civilization.

[0006] However, the existing photothermal technology for producing green ammonia simply uses solar thermal energy to convert solar energy into the electricity required for the operation of the synthetic green ammonia system; from the overall process perspective, the efficiency of solar energy utilization is not high. Summary of the invention

[0007] In view of this, the present invention provides a green ammonia synthesis system to solve the problem that the existing photothermal technology for producing green ammonia simply utilizes solar energy to convert solar energy into electrical energy required for the operation of the green ammonia synthesis system; from the perspective of the overall process, the utilization efficiency of solar energy is not high.

[0008] The present invention provides a green ammonia synthesis system, comprising:

[0009] A third heat storage structure stores a heat storage medium;

[0010] A photothermal device connected to the third heat storage structure, the photothermal device is suitable for converting sunlight into thermal energy and using the thermal energy to heat the heat storage medium transmitted by the third heat storage structure;

[0011] A first heat storage structure, connected to the photothermal device, the first heat storage structure being suitable for receiving a heated heat storage medium;

[0012] a steam generator connected to the first heat storage structure, the steam generator being adapted to receive the heated heat storage medium and utilize the heat storage medium to heat the water medium to generate steam;

[0013] a steam turbine connected to the steam generator, the steam turbine being adapted to receive steam and utilize the steam to drive the steam turbine to perform work;

[0014] A generator connected to the steam turbine, the generator being adapted to generate electricity as the steam turbine operates, thereby providing electrical energy for the green ammonia synthesis system;

[0015] A second heat storage structure is connected to the steam generator; the second heat storage structure is suitable for receiving the heat storage medium that has been cooled once;

[0016] an air compression, liquefaction and separation subsystem, adapted to sequentially compress and liquefy air into liquid air, and separate part of the liquid air into liquid oxygen and liquid nitrogen, and to be provided with electrical energy by the generator;

[0017] A first heat exchanger is connected to the air compression liquefaction separation subsystem, the second heat storage structure, and the third heat storage structure. The first heat exchanger is suitable for receiving the heat storage medium with a primary cooling, heating part of the liquid air of the air compression liquefaction separation subsystem into gaseous air by using the heat storage medium with a primary cooling, and transporting the heat storage medium with a secondary cooling to the third heat storage structure;

[0018] a turbine generator set connected to the first heat exchanger, the turbine generator set being adapted to receive the gaseous air heated by the first heat exchanger to generate electricity as a supplement to the electricity generated by the generator;

[0019] A second heat exchanger is connected to the air compression liquefaction separation subsystem, the second heat storage structure, and the photothermal device. The second heat exchanger is suitable for receiving the heat storage medium with a primary cooling, using the heat storage medium with a primary cooling to heat the liquid nitrogen separated by the air compression liquefaction separation subsystem, vaporizing the liquid nitrogen into nitrogen gas, and transporting the heat storage medium with a secondary cooling to the photothermal device to reheat the heat storage medium with a secondary cooling;

[0020] a water electrolysis subsystem adapted to decompose water into hydrogen and oxygen;

[0021] The green ammonia synthesis subsystem is connected to the second heat exchanger and the water electrolysis subsystem. The green ammonia synthesis subsystem is suitable for receiving the nitrogen heated by the second heat exchanger and the hydrogen produced by the water electrolysis subsystem, and synthesizing the nitrogen and hydrogen into ammonia. Beneficial effect: The present application adopts the above technical solution. On the one hand, it drives the operation of the green ammonia synthesis system by converting sunlight into electrical energy. On the other hand, the heat storage medium of the thermodynamic cycle directly provides the required heat energy for liquid air and liquid nitrogen, avoiding the loss of multiple energy conversions, solving the problem of low energy utilization efficiency in the existing green ammonia synthesis technology, significantly improving the utilization efficiency of solar energy, basically not needing to build an energy storage system, and significantly reducing the cost of green ammonia synthesis. In addition, when there is sufficient sunlight, the excess heat energy can be stored. When there is insufficient sunlight and the produced electricity is not enough to maintain the normal operation of the green ammonia synthesis system, the stored heat energy can be converted into electricity for energy supply, so that the entire green ammonia synthesis system can operate efficiently, and renewable energy can be effectively utilized more and better. When the electricity produced by photothermal technology is too much to be fully used, the electricity of the generator converted by photothermal power is used to power the air compression liquefaction separation subsystem, and the air stores the electricity in the form of liquid air. When the electricity generated is too little to maintain the operation of the green ammonia synthesis system, the liquid air is converted into gaseous form, and the energy is converted into electricity through the turbine generator set for use by the green ammonia synthesis system. That is, the green ammonia synthesis system has a certain flexibility to ensure power supply, overcome the defect of the mismatch between the intermittent volatility of solar energy and the continuity of the synthetic ammonia process, ensure the stable operation of the green ammonia synthesis system without external power supply, and can reasonably use the heat carried by the heat storage medium, further improving the energy utilization efficiency of the green ammonia synthesis system. At the same time, because the energy is stored by air liquefaction, there is no need to build a special energy storage system, which not only significantly saves costs, but also reduces the number of equipment construction and maintenance.

[0022] Optionally, the air compression liquefaction separation subsystem comprises:

[0023] A first filtering and drying device, adapted to filter and dry the air;

[0024] an air compressor unit connected to the first filtering and drying device, the air compressor unit being adapted to compress the filtered and dried air and being provided with electric energy by the generator;

[0025] a first energy-saving heat exchange device, connected to the air compressor unit and the steam generator; the first energy-saving heat exchange device is suitable for heating the water medium by utilizing the compression heat of the air compression process, and conveying the heated water medium to the steam generator;

[0026] A liquid air condensation tower connected to the first energy-saving heat exchange device, the liquid air condensation tower being suitable for condensing and cooling the compressed and cooled air into liquid air;

[0027] a first liquid air storage unit connected to the liquid air condensation tower and the first heat exchanger, the first liquid air storage unit being adapted to receive and store liquid air and to deliver part of the liquid air to the first heat exchanger; the liquid air delivered by the first liquid air storage unit to the first heat exchanger after being heated acts on the turbine generator set to generate electric energy as the first part of electric energy;

[0028] an air separation device connected to the first liquid air storage unit, wherein the air separation device is adapted to separate the liquid air delivered by the first liquid air storage unit into oxygen and nitrogen;

[0029] a second liquid air storage unit connected to the air separation unit and the first heat exchanger, the second liquid air storage unit being adapted to receive the liquid air remaining after the air separation unit separates the liquid air, and to deliver the remaining liquid air to the first heat exchanger; the liquid air delivered by the second liquid air storage unit to the first heat exchanger after heating acts on the turbine generator set to generate electric energy as the second part of electric energy; the first part of electric energy serves as a supplement to the second part of electric energy;

[0030] a first filtering and purifying device, connected to the air separation device, and adapted to filter and purify the nitrogen separated by the air separation device;

[0031] A liquid nitrogen distillation device connected to the first filtering and purifying device, wherein the liquid nitrogen distillation device is suitable for distilling and purifying liquid nitrogen from filtered and purified nitrogen;

[0032] a liquid nitrogen storage unit connected to the liquid nitrogen rectification device and the second heat exchanger, wherein the liquid nitrogen storage unit is suitable for receiving and storing liquid nitrogen delivered by the liquid nitrogen rectification device and delivering the liquid nitrogen to the second heat exchanger;

[0033] a second filtering and purifying device, connected to the air separation device, and adapted to filter and purify the oxygen separated by the air separation device;

[0034] A liquid oxygen distillation device connected to the second filtering and purifying device, wherein the liquid oxygen distillation device is suitable for distilling and purifying liquid oxygen from filtered and purified oxygen;

[0035] The liquid oxygen storage unit is connected to the liquid oxygen distillation equipment, and the liquid oxygen storage unit is suitable for receiving and storing the liquid oxygen delivered by the liquid oxygen distillation equipment. Beneficial effect: The present application adopts the above technical scheme, utilizes the first energy-saving heat exchange device to recover the compression heat, and is integrated and utilized in the steam generator through the preheated water medium, provides thermal energy to the steam generator, and increases the temperature of the water medium used in the steam generator. The preheated water medium is then converted into steam after heat exchange with the heat storage medium, and the generator is driven by the gas turbine to generate electricity. In the process of heat exchange between the water medium used in the steam generator and the first energy-saving heat exchange device, while obtaining the preheated water medium at a higher temperature, the purpose of cooling the compressed air is also achieved. In addition, not only the nitrogen required for the production of green ammonia is obtained through the air compression liquefaction separation subsystem, but also the by-products such as liquid nitrogen and liquid oxygen produced can be sold separately, thereby improving economic benefits and reducing costs. At the same time, when the electricity generated by the generator is not enough to maintain the operation of the green ammonia synthesis system, the second part of the electricity can supplement to maintain the operation of the green ammonia synthesis system; when the second part of the electricity is not enough to maintain the operation of the green ammonia synthesis system, the first part of the electricity can supplement to maintain the operation of the green ammonia synthesis system.

[0036] Optionally, the air compressor unit is a multi-stage compressor, and exhaust gas from each stage of the compressor passes through the first energy-saving heat exchange device. Beneficial effects: The present application adopts the above technical solution to fully utilize compression heat to heat the water medium.

[0037] Optionally, the air compression liquefaction separation subsystem further includes:

[0038] A first gas booster is connected between the liquid nitrogen rectification equipment and the gas inlet of the first filtering and purifying device; the first gas booster is suitable for boosting the pressure of the uncondensed cryogenic nitrogen and then re-transporting it to the first filtering and purifying device;

[0039] The second gas booster is connected between the liquid oxygen distillation equipment and the air inlet of the second filtering and purifying device; the second gas booster is suitable for boosting the pressure of the uncondensed cryogenic oxygen and then re-transporting it to the second filtering and purifying device. Beneficial effect: The present application adopts the above technical solution, and the first gas booster is used to provide nitrogen raw materials and cold supplement to the liquid nitrogen distillation equipment to save energy and improve the conversion rate. The second gas booster is used to provide oxygen raw materials and cold supplement to the liquid oxygen distillation equipment to save energy and improve the conversion rate.

[0040] Optionally, the water electrolysis subsystem comprises:

[0041] A third filtering and purifying device, adapted to filter and purify water;

[0042] A water electrolysis device connected to the third filtering and purifying device, wherein the water electrolysis device is suitable for electrolyzing filtered and purified water into hydrogen and oxygen;

[0043] a second energy-saving heat exchange device, connected to the water electrolysis device and the steam generator, adapted to receive oxygen electrolyzed by the water electrolysis device, heat the water medium by using the water electrolysis heat of the oxygen, and transport the heated water medium to the steam generator;

[0044] A second filtering and drying device is connected to the second energy-saving heat exchange device and the liquid oxygen distillation device, and the second filtering and drying device is suitable for receiving, filtering and drying the cooled oxygen, and delivering the filtered and dried oxygen to the liquid oxygen distillation device;

[0045] The third filtering and drying device is connected to the water electrolysis device and the green ammonia synthesis subsystem. The third filtering and drying device is suitable for receiving, filtering and drying the hydrogen electrolyzed by the water electrolysis device, and delivering the filtered and dried hydrogen to the green ammonia synthesis subsystem. Beneficial effect: The present application adopts the above technical scheme, uses the second energy-saving heat exchange device to recover the water electrolysis heat of oxygen, and uses the preheated water medium to be integrated and utilized in the steam generator, provides thermal energy to the steam generator, and increases the temperature of the water medium used in the steam generator. The preheated water medium is then converted into steam after heat exchange with the heat storage medium, and the generator is driven by the gas turbine to generate electricity. In the process of heat exchange between the water medium used in the steam generator and the second energy-saving heat exchange device, while obtaining the preheated water medium at a higher temperature, the purpose of cooling oxygen is also achieved. In addition, the water electrolysis subsystem cancels the hydrogen storage unit, and hydrogen continuously enters the green ammonia synthesis subsystem, realizing efficient production of the water electrolysis subsystem. At the same time, the liquid oxygen and oxygen in the liquid oxygen distillation equipment can be sold as by-products, improving economic benefits and reducing costs. In addition, the heat generated by water electrolysis in hydrogen can provide heat for subsequent reactions to further achieve energy-saving effects.

[0046] Optionally, the green ammonia synthesis subsystem comprises:

[0047] a synthesis gas compressor connected to the second heat exchanger and the water electrolysis subsystem; the synthesis gas compressor is adapted to receive the nitrogen transmitted by the second heat exchanger and the hydrogen transmitted by the water electrolysis subsystem, and pressurize the mixed nitrogen and hydrogen;

[0048] an ammonia synthesis tower connected to the synthesis gas compressor, the ammonia synthesis tower being adapted to receive the mixed pressurized nitrogen and hydrogen, and to perform a synthesis reaction to generate ammonia;

[0049] A gas-liquid separation device connected to the ammonia synthesis tower, the gas-liquid separation device is suitable for separating liquid ammonia transported by the ammonia synthesis tower;

[0050] a third energy-saving heat exchange device, connected to the gas-liquid separation device and the steam generator, the third energy-saving heat exchange device being adapted to receive the liquid ammonia separated by the gas-liquid separation device, heat the water medium by utilizing the reaction heat of the liquid ammonia, and transport the heated water medium to the steam generator;

[0051] The liquid ammonia storage unit is connected to the third energy-saving heat exchange device, and the liquid ammonia storage unit is suitable for receiving and storing the cooled liquid ammonia transported by the third energy-saving heat exchange device. Beneficial effect: The present application adopts the above technical solution, and utilizes the third energy-saving heat exchange device to recover the heat energy generated by the liquid ammonia in the ammonia synthesis process, and is integrated and utilized in the steam generator through the preheated water medium, so as to provide heat energy to the steam generator and increase the temperature of the water medium used in the steam generator. The preheated water medium is then converted into steam after heat exchange with the heat storage medium, and the generator is driven by the gas turbine to generate electricity. In the process of heat exchange between the water medium used in the steam generator and the third energy-saving heat exchange device, while obtaining the preheated water medium at a higher temperature, the purpose of cooling the liquid ammonia is also achieved. The present application generates excellent energy coupling by integrated utilization of heat in the ammonia production process, which can cool the liquid ammonia while saving energy and reducing consumption, thereby ensuring the efficient operation of the green ammonia synthesis subsystem.

[0052] Optionally, the gas-liquid separation device is also suitable for separating the mixed gas delivered by the ammonia synthesis tower and re-delivering the mixed gas to the ammonia synthesis tower, wherein the mixed gas is a mixture of ammonia, unreacted hydrogen and nitrogen. The present application adopts the above technical solution to replenish raw materials and heat, promote conversion rate, save energy and make full use of raw materials by re-delivering the mixed gas to the ammonia synthesis tower.

[0053] Optionally, according to the real-time rate of hydrogen production of the water electrolysis subsystem, the flow rate of nitrogen delivered by the second heat exchanger is controlled in real time, so that hydrogen and nitrogen enter the synthesis gas compressor at a volume ratio of 3:1. Beneficial effect: The present application adopts the above technical solution to adjust the flow rate of nitrogen produced by the hole in real time according to the output rate of hydrogen to replace the previous design of hydrogen storage equipment. On the one hand, it can ensure sufficient supply of hydrogen, and on the other hand, it can reduce the risk of leakage and explosion caused by high-pressure and large-scale storage in the hydrogen storage link, while reducing the number of devices invested in hydrogen production, significantly reducing the synthesis cost of green ammonia, equipment cost and maintenance cost of equipment.

[0054] Optionally, the photothermal device comprises:

[0055] concentrators, suitable for focusing the radiation of sunlight;

[0056] Sun Tower;

[0057] A heat absorbing device is arranged on the solar tower;

[0058] The photothermal device is suitable for focusing the radiation of sunlight into a heat absorption device by using a concentrator, and heating the heat storage medium by using the heat absorption device.

[0059] Optionally, the second heat storage structure is connected to the third heat storage structure via a first valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 It is a connection schematic diagram of the green ammonia synthesis system provided in an embodiment of the present invention.

[0062] Description of reference numerals:

[0063] 1. Photothermal equipment; 2. First heat storage structure; 3. Steam generator; 4. Steam turbine; 5. Generator; 6. Second heat storage structure; 7. First valve; 8. Third heat storage structure; 9. Second valve; 10. First filter and dryer; 11. Air compressor unit; 12. First energy-saving heat exchanger; 13. Third valve; 14. Liquid air condensation tower; 15. First liquid air storage unit; 16. Fourth valve; 17. First heat exchanger; 18. Turbine generator unit; 19. Fifth valve; 20. Air separation unit; 21. Sixth valve; 22. Second liquid air storage unit; 23. Seventh valve; 24. Eighth valve; 25. First filter and purification device; 26. Liquid nitrogen distillation equipment; 27. First gas booster 1. The second heat exchanger; 2. The tenth valve; 3. The eleventh valve; 3. The second filter and purification device; 3. The liquid oxygen distillation equipment; 3. The second gas booster; 3. The liquid oxygen storage unit; 3. The third filter and purification device; 3. The water electrolysis device; 3. The second energy-saving heat exchange device; 4. The second filter and drying device; 4. The twelfth valve; 4. The third filter and drying device; 4. The thirteenth valve; 4. The synthesis gas compressor; 4. The ammonia synthesis tower; 4. The gas-liquid separation device; 4. The third energy-saving heat exchange device; 4. The fourteenth valve; 49. The liquid ammonia storage unit; 50. Sunlight; 51. Aqueous medium; 52. Air; 53. Water. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0065] In the existing raw material production and synthesis process of green ammonia, a large amount of waste heat is generated, which is discharged into the environment, resulting in a huge waste of energy. In addition, due to the intermittent volatility of solar energy itself, it is necessary to build an energy storage system and use it in conjunction with solar energy, which significantly increases the cost of green ammonia synthesis and does not completely couple the photothermal technology with the green ammonia synthesis system. It is also due to the above reasons that this application proposes a green ammonia synthesis system.

[0066] like Figure 1 A specific implementation of the green ammonia synthesis system shown includes: a third heat storage structure 8, a photothermal device 1, a first heat storage structure 2, a steam generator 3, a steam turbine 4, a generator 5, a second heat storage structure 6, an air compression liquefaction separation subsystem, a first heat exchanger 17, a turbine generator set 18, a second heat exchanger 30, a water electrolysis subsystem and a green ammonia synthesis subsystem. The green ammonia synthesis system described in the present application is based on photothermal technology and has the characteristics of low energy consumption. The green ammonia synthesis system described in the present application truly realizes the two-way coupling of solar energy heat storage and ammonia synthesis process, which not only realizes zero carbon emissions in the whole process of green ammonia synthesis, but also makes the most of solar energy, reduces energy loss, improves the production efficiency and energy utilization efficiency of green ammonia, reduces costs, improves economy, promotes the consumption of renewable energy, meets the needs of environmental protection and energy storage, creates considerable social and economic benefits, and has a certain enlightenment effect on the future industrial production structure. Specifically, the first heat storage structure 2, the second heat storage structure 6 and the third heat storage structure 8 can all be heat storage and heat exchange containers, and the heat storage and heat exchange containers have strong insulation properties; the steam turbine 4 is an industrial steam turbine; the first heat exchanger 17 and the second heat exchanger 30 can both be vaporization heat exchange devices;

[0067] The third heat storage structure 8 stores a heat storage medium, and specifically, the heat storage medium can be a molten inorganic salt. The photothermal device 1 is connected to the third heat storage structure 8, and the photothermal device 1 is suitable for converting sunlight 50 into thermal energy, and using the thermal energy to heat the heat storage medium transmitted by the third heat storage structure 8. The first heat storage structure 2 is connected to the photothermal device 1, and the first heat storage structure 2 is suitable for receiving the heated heat storage medium. The steam generator 3 is connected to the first heat storage structure 2, and the steam generator 3 is suitable for receiving the heated heat storage medium, and using the heat storage medium to heat the water medium 51 to generate steam. The steam turbine 4 is connected to the steam generator 3, and the steam turbine 4 is suitable for receiving steam and using steam to drive the steam turbine 4 to work. The generator 5 is connected to the steam turbine 4, and the generator 5 is suitable for generating electricity as the steam turbine 4 runs, thereby providing electrical energy for the green ammonia synthesis system. The second heat storage structure 6 is connected to the steam generator 3; the second heat storage structure 6 is suitable for receiving the heat storage medium that has been cooled once. The second heat storage structure 6 can be connected to the third heat storage structure 8 via a first valve 7 .

[0068] The air compression and liquefaction separation subsystem is suitable for compressing and liquefying air 52 into liquid air in sequence, and separating part of the liquid air into liquid oxygen and liquid nitrogen, and the generator 5 provides electric energy for the air compression and liquefaction separation subsystem. The first heat exchanger 17 is connected to the air compression and liquefaction separation subsystem, the second heat storage structure 6, and the third heat storage structure 8. The first heat exchanger 17 is suitable for receiving the heat storage medium with a primary cooling, using the heat storage medium with a primary cooling to heat part of the liquid air of the air compression and liquefaction separation subsystem into gaseous air, and transporting the heat storage medium with a secondary cooling to the third heat storage structure 8. A second valve 9 is provided between the first heat exchanger 17 and the second heat storage structure 6. The turbine generator set 18 is connected to the first heat exchanger 17, and the turbine generator set 18 is suitable for receiving the gaseous air heated by the first heat exchanger 17 to generate electricity as a supplement to the electric energy generated by the generator 5. The second heat exchanger 30 is connected to the air compression liquefaction separation subsystem, the second heat storage structure 6, and the photothermal device 1. The second heat exchanger 30 is suitable for receiving the heat storage medium with a primary cooling, using the heat storage medium with a primary cooling to heat the liquid nitrogen separated by the air compression liquefaction separation subsystem, and vaporizing the liquid nitrogen into nitrogen gas, and transporting the heat storage medium with a secondary cooling to the photothermal device 1 to reheat the heat storage medium with a secondary cooling. A tenth valve 31 is provided between the second heat exchanger 30 and the second heat storage structure 6.

[0069] The water electrolysis subsystem is suitable for decomposing water 53 into hydrogen and oxygen. The green ammonia synthesis subsystem is connected to the second heat exchanger 30 and the water electrolysis subsystem, and is suitable for receiving the nitrogen heated by the second heat exchanger 30 and the hydrogen generated by the water electrolysis subsystem, and synthesizing the nitrogen and hydrogen into ammonia.

[0070] Specifically, the air compression liquefaction separation subsystem includes: a first filtering and drying device 10, an air compressor unit 11, a first energy-saving heat exchange device 12, a liquid air condensation tower 14, a first liquid air storage unit 15, an air separation device 20, a second liquid air storage unit 22, a first filtering and purifying device 25, a liquid nitrogen rectification device 26, a liquid nitrogen storage unit 28, a second filtering and purifying device 33, a liquid oxygen rectification device 34, a liquid oxygen storage unit 36, a first gas booster 27 and a second gas booster 35. The first liquid air storage unit 15 and the second liquid air storage unit 22 can both be liquid air storage tanks.

[0071] The first filtering and drying device 10 is suitable for filtering and drying the air 52. The air compressor unit 11 is connected to the first filtering and drying device 10, and the air compressor unit 11 is suitable for compressing the filtered and dried air, and the generator 5 provides electric energy for the air compressor unit 11. The first energy-saving heat exchange device 12 is connected to both the air compressor unit 11 and the steam generator 3; the first energy-saving heat exchange device 12 is suitable for heating the water medium 51 by using the compression heat of the air compression process, and transporting the heated water medium 51 to the steam generator 3. Further, the air compressor unit 11 is a multi-stage compressor, and the exhaust gas of each stage of the compressor passes through the first energy-saving heat exchange device 12.

[0072] The liquid air condensation tower 14 is connected to the first energy-saving heat exchange device 12, and the liquid air condensation tower 14 is suitable for condensing and cooling the compressed and cooled air into liquid air. A third valve 13 is provided between the liquid air condensation tower 14 and the first energy-saving heat exchange device 12. The first liquid air storage unit 15 is connected to the first heat exchanger 17 of the liquid air condensation tower 14, and the first liquid air storage unit 15 is suitable for receiving and storing liquid air, and delivering part of the liquid air to the first heat exchanger 17; the liquid air delivered to the first heat exchanger 17 by the first liquid air storage unit 15 after heating acts on the electric energy generated by the turbine generator set 18 as the first part of the electric energy. A fourth valve 16 is provided between the first liquid air storage unit 15 and the first heat exchanger 17. The air separation device 20 is connected to the first liquid air storage unit 15, and the air separation device 20 is suitable for separating the liquid air delivered by the first liquid air storage unit 15 into oxygen and nitrogen. A fifth valve 19 is provided between the air separation device 20 and the first liquid air storage unit 15. The second liquid air storage unit 22 is connected to both the air separation device 20 and the first heat exchanger 17. The second liquid air storage unit 22 is suitable for receiving the remaining liquid air after the air separation device 20 separates the liquid air, and transporting the remaining liquid air to the first heat exchanger 17; a sixth valve 21 is provided between the liquid air outlet of the air separation device 20 and the second liquid air storage unit 22, and a seventh valve 23 is provided between the second liquid air storage unit 22 and the first heat exchanger 17. The liquid air transported to the first heat exchanger 17 by the second liquid air storage unit 22 after heating acts on the turbine generator set 18 to generate electric energy as the second part of electric energy; the first part of electric energy is used as a supplement to the second part of electric energy. The first filtering and purifying device 25 is connected to the air separation device 20, and the first filtering and purifying device 25 is suitable for filtering and purifying the nitrogen separated by the air separation device 20. An eighth valve 24 is provided between the nitrogen outlet of the air separation device 20 and the first filtering and purifying device 25. The liquid nitrogen distillation device 26 is connected to the first filtering and purifying device 25, and the liquid nitrogen distillation device 26 is suitable for distilling and purifying the filtered and purified nitrogen to obtain liquid nitrogen, and the liquid nitrogen is high-purity low-temperature liquid nitrogen. The liquid nitrogen distillation device 26 is a liquid nitrogen high-pressure distillation device, and the liquid nitrogen storage unit 28 is connected to the liquid nitrogen distillation device 26 and the second heat exchanger 30. The liquid nitrogen storage unit 28 is suitable for receiving and storing the liquid nitrogen transported by the liquid nitrogen distillation device 26, and transporting the liquid nitrogen to the second heat exchanger 30. A ninth valve 29 is provided between the liquid nitrogen storage unit 28 and the second heat exchanger 30. The liquid nitrogen in the liquid nitrogen storage unit 28 can be directly sold as needed. The second filtering and purifying device 33 is connected to the air separation device 20, and the second filtering and purifying device 33 is suitable for filtering and purifying the oxygen separated by the air separation device 20.An eleventh valve 32 is provided between the oxygen outlet of the air separation device 20 and the second filtering and purifying device 33. The liquid oxygen distillation device 34 is connected to the second filtering and purifying device 33, and the liquid oxygen distillation device 34 is suitable for distilling and purifying the filtered and purified oxygen to obtain liquid oxygen. The liquid oxygen distillation device 34 is a liquid oxygen high-pressure distillation device, and the liquid oxygen storage unit 36 ​​is connected to the liquid oxygen distillation device 34, and the liquid oxygen storage unit 36 ​​is suitable for receiving and storing the liquid oxygen delivered by the liquid oxygen distillation device 34.

[0073] The first gas booster 27 is connected between the liquid nitrogen rectification device 26 and the gas inlet of the first filtering and purifying device 25; the first gas booster 27 is suitable for boosting the pressure of the uncondensed cryogenic nitrogen and then delivering it to the first filtering and purifying device 25. The second gas booster 35 is connected between the liquid oxygen rectification device 34 and the gas inlet of the second filtering and purifying device 33; the second gas booster 35 is suitable for boosting the pressure of the uncondensed cryogenic oxygen and then delivering it to the second filtering and purifying device 33.

[0074] Specifically, the water electrolysis subsystem includes: a third filtering and purifying device 37 , a water electrolysis device 38 , a second energy-saving heat exchange device 39 , a second filtering and drying device 40 and a third filtering and drying device 42 .

[0075] The third filtering and purifying device 37 is suitable for filtering and purifying water 53. The electrolytic water device 38 is connected to the third filtering and purifying device 37, and the electrolytic water device 38 is suitable for electrolyzing the filtered and purified water 53 into hydrogen and oxygen. The second energy-saving heat exchange device 39 is connected to the electrolytic water device 38 and the steam generator 3, and the second energy-saving heat exchange device 39 is suitable for receiving the oxygen electrolyzed by the electrolytic water device 38, using the water electrolysis heat of oxygen to heat the water medium 51, and delivering the heated water medium 51 to the steam generator 3. The second filtering and drying device 40 is connected to the second energy-saving heat exchange device 39 and the liquid oxygen distillation equipment 34, and the second filtering and drying device 40 is suitable for receiving, filtering and drying the cooled oxygen, and delivering the filtered and dried oxygen to the liquid oxygen distillation equipment 34. A twelfth valve 41 is provided between the second filtering and drying device 40 and the liquid oxygen distillation equipment 34. The third filtering and drying device 42 is connected to both the water electrolysis device 38 and the green ammonia synthesis subsystem. The third filtering and drying device 42 is suitable for receiving, filtering and drying hydrogen electrolyzed by the water electrolysis device 38, and delivering the filtered and dried hydrogen to the green ammonia synthesis subsystem. A thirteenth valve 43 is provided between the third filtering and drying device 42 and the green ammonia synthesis subsystem.

[0076] Specifically, the green ammonia synthesis subsystem includes: a synthesis gas compressor 44 , an ammonia synthesis tower 45 , a gas-liquid separation device 46 , a third energy-saving heat exchange device 47 and a liquid ammonia storage unit 49 .

[0077] The synthesis gas compressor 44 is connected to the second heat exchanger 30 and the water electrolysis subsystem; the synthesis gas compressor 44 is suitable for receiving nitrogen transmitted by the second heat exchanger 30 and hydrogen transmitted by the third filtering and drying device 42 of the water electrolysis subsystem, and pressurizing the mixed nitrogen and hydrogen. Further, according to the real-time rate of hydrogen production of the water electrolysis subsystem, the flow rate of nitrogen delivered by the second heat exchanger 30 is controlled in real time, so that hydrogen and nitrogen enter the synthesis gas compressor 44 according to the volume ratio of 3:1.

[0078] The ammonia synthesis tower 45 is connected to the synthesis gas compressor 44, and is suitable for receiving the mixed pressurized nitrogen and hydrogen to perform a synthesis reaction to generate ammonia. The gas-liquid separation device 46 is connected to the ammonia synthesis tower 45, and is suitable for separating the liquid ammonia transported by the ammonia synthesis tower 45. Further, the gas-liquid separation device 46 is also suitable for separating the mixed gas transported by the ammonia synthesis tower 45 and transporting the mixed gas back to the ammonia synthesis tower 45, and the mixed gas is a mixture of ammonia, unreacted hydrogen and nitrogen.

[0079] The third energy-saving heat exchange device 47 is connected to the gas-liquid separation device 46 and the steam generator 3. The third energy-saving heat exchange device 47 is suitable for receiving the liquid ammonia separated by the gas-liquid separation device 46, heating the water medium 51 by using the reaction heat of the liquid ammonia, and delivering the heated water medium 51 to the steam generator 3. The liquid ammonia storage unit 49 is connected to the third energy-saving heat exchange device 47. The liquid ammonia storage unit 49 is suitable for receiving and storing the cooled liquid ammonia delivered by the third energy-saving heat exchange device 47. A fourteenth valve 48 is provided between the liquid ammonia storage unit 49 and the third energy-saving heat exchange device 47.

[0080] Specifically, the photothermal device 1 includes: a concentrator, a solar tower and a heat absorption device. The concentrator is suitable for focusing the radiation of sunlight 50. The heat absorption device is arranged on the top of the solar tower. The photothermal device 1 is suitable for focusing the radiation of sunlight 50 into the heat absorption device by using the concentrator, and heating the heat storage medium by using the heat absorption device.

[0081] The main working process principle of the green ammonia synthesis system described in the present application is briefly described as follows: after absorbing the solar energy collected by the photothermal device 1, the temperature of the heat storage medium entering the first heat storage structure 2 can reach 480°C to 550°C, and then enters the working medium inlet of the steam generator 3 from the working medium heat exchange outlet of the first heat storage structure 2, heating the preheated water medium 51 in the steam generator 3 into steam, and the steam is introduced from the steam outlet of the steam generator 3 to the steam inlet of the steam turbine 4 through a pipeline, driving the steam turbine 4 to do work, and the steam turbine 4 is coaxially connected to the generator 5 to provide mechanical energy for the generator 5 to generate electricity; the electric energy generated by the generator 5 is used in the entire green ammonia synthesis system, and the heat storage medium after heat exchange with the water medium 51 is discharged from the heat exchange outlet of the steam generator 3 and is transported to the second heat storage structure 6; the temperature in the second heat storage structure 6 is between 300°C and 350°C.

[0082] The working fluid heat exchange outlet of the second heat storage structure 6 is connected to the working fluid heat exchange inlet of the third heat storage structure 8 through the pipeline and the first valve 7; the second heat storage structure 6 is connected to the working fluid heat exchange inlet of the first heat exchanger 17 through the pipeline and the second valve 9; the second heat storage structure 6 is connected to the working fluid heat exchange inlet of the second heat exchanger 30 through the pipeline and the tenth valve 31. The third heat storage structure 8 is connected to the working fluid heat exchange outlet of the first heat exchanger 17 through a pipeline. After the heat storage medium releases heat and enters the third heat storage structure 8, the temperature of the heat storage medium is between 150°C and 220°C. The third heat storage structure 8 is then connected to the working fluid heat exchange inlet of the photothermal device 1 through a pipeline, and absorbs the heat generated by solar energy in the photothermal device 1 again, ready to enter a new round of circulation.

[0083] The raw air 52 is first filtered and dried by the first filter-drying device 10, and then sent to the air compressor unit 11 for compression. The air compressor unit 11 includes a plurality of integrated multi-stage compressors. The multi-stage compressors are split-shafts and are respectively connected in parallel with the first energy-saving heat exchange device 12. Each split-shaft is dynamically connected to the main drive shaft, and the exhaust of each stage of the compressor passes through the first energy-saving heat exchange device 12. The raw air 52 at normal temperature and pressure is filtered and dried, and then compressed to a high-pressure and high-temperature state by the air compressor unit 11, and cooled in the first energy-saving heat exchange device 12. The first energy-saving heat exchange device 12 is provided with a water supply inlet, which is connected to the delivery pipeline of the water medium 51. The hot water outlet of the first energy-saving heat exchange device 12 is connected to the hot water inlet of the steam generator 3 through the delivery pipeline of the water medium 51. After the water medium 51 in the first energy-saving heat exchange device 12 recovers the heat generated by the air 52 during the compression process, it enters the steam generator 3 and is further heated into steam. At this time, the raw air 52 becomes a normal temperature and high-pressure state; the normal temperature and high-pressure air 52 discharged from the first energy-saving heat exchange device 12 enters the liquid air condensation tower 14 after passing through the third valve 13, is condensed and cooled into liquid air, and is finally sent to the first liquid air storage unit 15 for storage.

[0084] The liquid air in the first liquid air storage unit 15 enters the first heat exchanger 17 through the fourth valve 16, absorbs the heat of the heat storage medium in the first heat exchanger 17 and is converted from liquid to gas, and the stored molecular potential energy is converted into power through the turbine action of the turbine generator set 18, driving the dedicated generator of the turbine generator set 18 to generate electricity, and the electricity is applied to the entire green ammonia synthesis system; especially when the electricity generated by the generator 5 is insufficient to maintain the smooth operation of the entire green ammonia synthesis system and the liquid air in the second liquid air storage unit 22 is exhausted, the power generation of the turbine generator set 18 is used as a supplement. The heat storage medium after heat exchange in the first heat exchanger 17 enters the third heat storage structure 8. Specifically, when the power produced by the generator 5 is in excess and sufficient to support the entire green ammonia synthesis system, part of the power can be used for the air compressor unit 11, etc. to liquefy the outside air 52 and store the liquid air in the first liquid air storage unit 15; when the power produced by the generator 5 is insufficient to fully support the operation of the entire green ammonia synthesis system, and the liquid air in the second liquid air storage unit 22 is exhausted, the liquid air in the first liquid air storage unit 15 can be converted into gaseous air to perform energy conversion, and the energy can be converted into power for the turbine generator set 18 to generate electricity, and then the electricity can be used for the entire green ammonia synthesis system.

[0085] More specifically, the first liquid air storage unit 15 is connected to the air separation device 20 through the fifth valve 19, and the liquid air is separated in the air separation device 20 through the fifth valve 19 and processed into oxygen, nitrogen and the remaining liquid gas. The remaining liquid gas separated by the air separation device 20 passes through the sixth valve 21 and is stored in the second liquid air storage unit 22, and the second liquid air storage unit 22 is connected to the first heat exchanger 17 through the seventh valve 23. When the power generated by the generator 5 is insufficient, the remaining liquid air in the second liquid air storage unit 22 enters the first heat exchanger 17 through the seventh valve 23, where it absorbs the heat of the heat storage medium and vaporizes. The power generated by the liquid-gas conversion drives the turbine generator set 18 to generate electricity to maintain the operation of the entire green ammonia synthesis system. The heat storage medium after heat exchange enters the third heat storage structure 8.

[0086] The nitrogen separated by the air separation device 20 is purified by the eighth valve 24 and the first filtering and purifying device 25, and then enters the liquid nitrogen distillation device 26 for distillation and purification. The nitrogen is separated into cryogenic nitrogen and high-purity liquid nitrogen. The high-purity liquid nitrogen is discharged from the separation liquid outlet and stored in the liquid nitrogen storage unit 28. The uncondensed cryogenic nitrogen is discharged from the separation gas outlet and enters the branch pipeline. After being pressurized by the first gas booster 27, it is processed by the first filtering and purifying device 25 again and enters the liquid nitrogen distillation device 26 again to provide nitrogen raw material and cold supplement for it, so as to save energy and improve the conversion rate.

[0087] The high-purity liquid nitrogen in the liquid nitrogen storage unit 28 is sent to the second heat exchanger 30 under the control of the ninth valve 29, where the liquid nitrogen absorbs the heat of the heat storage medium and heats up and vaporizes. After becoming high-temperature nitrogen, it enters the synthesis gas compressor 44, and the heat storage medium after heat exchange enters the photothermal equipment 1.

[0088] The oxygen separated by the air separation device 20 is purified by the eleventh valve 32 and the second filtering and purifying device 33, and then enters the liquid oxygen distillation equipment 34 for distillation and purification. The oxygen is separated into cryogenic oxygen and high-purity liquid oxygen. The high-purity liquid oxygen is discharged from the separation liquid outlet and stored in the liquid oxygen storage unit 36. The uncondensed cryogenic oxygen is discharged from the separation gas outlet and enters the branch pipeline. After being pressurized by the second gas booster 35, it is re-processed by the second filtering and purifying device 33 and enters the liquid oxygen distillation equipment 34 again to provide oxygen raw materials and cold capacity supplement for the liquid oxygen distillation equipment 34 to save energy and improve the conversion rate.

[0089] After the external water 53 is purified by the third filtering and purifying device 37, the water electrolysis reaction is carried out by the water electrolysis device 38 to obtain hydrogen and oxygen. After the oxygen is discharged from the oxygen outlet of the water electrolysis device 38, it enters the second energy-saving heat exchange device 39, and exchanges heat with the water medium 51 entering from the water supply inlet. After absorbing the water electrolysis heat of oxygen, the water medium 51 is connected to the hot water inlet of the steam generator 3 through the hot water outlet of the second energy-saving heat exchange device 39 through a transmission pipeline, and is further heated into steam; after the oxygen in the second energy-saving heat exchange device 39 is cooled by heat exchange, it passes through the second filtering and drying device 40 and the twelfth valve 41 in turn, and is merged with the oxygen generated by the air separation device 20 into the liquid oxygen distillation equipment 34 for distillation, and finally discharged from the separation liquid outlet and stored in the liquid oxygen storage unit 36.

[0090] The hydrogen with electrolysis heat generated by the water electrolysis device 38 is discharged from the hydrogen outlet, passes through the third filtering and drying device 42 and the thirteenth valve 43, and enters the synthesis gas compressor 44, where it is mixed with the high-temperature nitrogen in a ratio of 3:1 and raised to the reaction pressure to obtain the high-temperature synthesis gas; the high-temperature synthesis gas is discharged from the outlet of the synthesis gas compressor 44 and transmitted to the mixed gas inlet of the ammonia synthesis tower 45, where an ammonia synthesis reaction is carried out inside the ammonia synthesis tower 45 to generate ammonia; the gas-liquid mixture in the ammonia synthesis tower 45 is discharged from the outlet of the ammonia synthesis tower 45 and enters the inlet of the gas-liquid separation device 46, where it is separated into a mixed gas and liquid ammonia by the gas-liquid separation device 46; the gas outlet of the gas-liquid separation device 46 is connected to the inlet of the ammonia synthesis tower 45 again, so that the separated mixed gas returns to the ammonia synthesis tower 45; the mixed gas contains part of the unreacted hydrogen and nitrogen, as well as the synthesized ammonia, and provides ammonia for the ammonia synthesis tower 45, and the raw materials and heat such as the unreacted hydrogen and nitrogen are supplemented, thereby promoting the conversion rate, saving energy, and making full use of the raw materials.

[0091] The liquid ammonia separated by the gas-liquid separation device 46 is discharged from the liquid outlet and enters the liquid ammonia inlet of the third energy-saving heat exchange device 47. The third energy-saving heat exchange device 47 is provided with a water supply inlet. The water medium 51 enters the third energy-saving heat exchange device 47 to exchange heat with the liquid ammonia. The liquid ammonia is cooled in the third energy-saving heat exchange device 47. At the same time, the hot water outlet of the third energy-saving heat exchange device 47 is connected to the hot water inlet of the steam generator 3 through a conveying pipeline. After absorbing the synthesis reaction heat of the liquid ammonia, the water medium 51 is connected to the hot water inlet of the steam generator 3 from the hot water outlet of the third energy-saving heat exchange device 47 through a conveying pipeline, and is further heated into steam. After the liquid ammonia in the third energy-saving heat exchange device 47 is cooled by heat exchange, it is stored in the liquid ammonia storage unit 49 under the control of the fourteenth valve 48.

[0092] The energy required by the green ammonia synthesis system described in the present application in the process of synthesizing green ammonia is all provided by solar energy, and the energy conversion efficiency η can be calculated using formula (1).

[0093] η=ΔH 氨气 / QL (1)

[0094] Where ΔH 氨气 It is the heat of combustion of unit mass of ammonia, expressed in kJ / kg; QL is the sum of solar energy received by the green ammonia synthesis system.

[0095] It has been verified that in ΔH 氨气 =18610 kJ / kg, the energy conversion efficiency η of the green ammonia synthesis system described in the present application is about 13.8%, which is at least 4.3% higher than that of the existing system where the photothermal subsystem and the synthetic green ammonia subsystem operate independently. If 2 tons of water are consumed for every ton of green ammonia produced, about 2.85×106 kJ~3.12×10 6 kJ of energy saving. In addition, the technical solution of the present application uses liquid air to store energy by setting up an air compression liquefaction separation subsystem, and does not need to build an additional special energy storage system; and the hydrogen storage unit is eliminated, and the flow rate of nitrogen delivered by the second heat exchanger 30 is controlled in real time according to the real-time rate of hydrogen production of the water electrolysis subsystem, replacing the design of the previous hydrogen storage equipment, which not only reduces safety risks but also reduces costs.

[0096] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A green ammonia synthesis system, characterized in that: include: A third heat storage structure (8) stores a heat storage medium; A photothermal device (1) connected to the third heat storage structure (8), wherein the photothermal device (1) is suitable for converting sunlight (50) into thermal energy and using the thermal energy to heat the heat storage medium transmitted by the third heat storage structure (8); A first heat storage structure (2) connected to the photothermal device (1), wherein the first heat storage structure (2) is suitable for receiving the heated heat storage medium; A steam generator (3) connected to the first heat storage structure (2), the steam generator (3) being adapted to receive the heated heat storage medium and utilize the heat storage medium to heat the water medium (51) to generate steam; A steam turbine (4) connected to the steam generator (3), wherein the steam turbine (4) is adapted to receive steam and utilize the steam to drive the steam turbine (4) to perform work; A generator (5) connected to the steam turbine (4), wherein the generator (5) is adapted to generate electricity as the steam turbine (4) operates, thereby providing electrical energy for the green ammonia synthesis system; A second heat storage structure (6) connected to the steam generator (3); the second heat storage structure (6) is suitable for receiving the heat storage medium that has been cooled once; an air compression, liquefaction and separation subsystem, adapted to compress and liquefy the air (52) into liquid air in sequence, and to separate part of the liquid air into liquid oxygen and liquid nitrogen, and to provide electrical energy from the generator (5); a first heat exchanger (17) connected to the air compression liquefaction separation subsystem, the second heat storage structure (6), and the third heat storage structure (8); the first heat exchanger (17) is adapted to receive the heat storage medium that has been cooled once, to heat part of the liquid air in the air compression liquefaction separation subsystem into gaseous air using the heat storage medium that has been cooled once, and to transport the heat storage medium that has been cooled twice to the third heat storage structure (8); a turbine generator set (18) connected to the first heat exchanger (17), the turbine generator set (18) being adapted to receive the gaseous air heated by the first heat exchanger (17) to generate electricity as a supplement to the electricity generated by the generator (5); a second heat exchanger (30) connected to the air compression liquefaction separation subsystem, the second heat storage structure (6), and the photothermal device (1); the second heat exchanger (30) is adapted to receive the heat storage medium that has been cooled once, use the heat storage medium that has been cooled once to heat the liquid nitrogen separated by the air compression liquefaction separation subsystem, vaporize the liquid nitrogen into nitrogen gas, and transport the heat storage medium that has been cooled twice to the photothermal device (1) to reheat the heat storage medium that has been cooled twice; a water electrolysis subsystem adapted to decompose water (53) into hydrogen and oxygen; The green ammonia synthesis subsystem is connected to the second heat exchanger (30) and the water electrolysis subsystem. The green ammonia synthesis subsystem is suitable for receiving the nitrogen heated by the second heat exchanger (30) and the hydrogen generated by the water electrolysis subsystem, and synthesizing the nitrogen and hydrogen into ammonia.

2. The green ammonia synthesis system according to claim 1, characterized in that: The air compression liquefaction separation subsystem comprises: A first filtering and drying device (10) adapted to filter and dry the air (52); An air compressor unit (11) connected to the first filtering and drying device (10), the air compressor unit (11) being suitable for compressing the filtered and dried air and being provided with electric energy by the generator (5); a first energy-saving heat exchange device (12) connected to the air compressor unit (11) and the steam generator (3); the first energy-saving heat exchange device (12) is suitable for heating the water medium (51) by using the compression heat of the air compression process, and transporting the heated water medium (51) to the steam generator (3); A liquid air condensation tower (14) connected to the first energy-saving heat exchange device (12), wherein the liquid air condensation tower (14) is suitable for condensing and cooling compressed and cooled air into liquid air; A first liquid air storage unit (15) is connected to the liquid air condensation tower (14) and the first heat exchanger (17); the first liquid air storage unit (15) is suitable for receiving and storing liquid air, and transmitting part of the liquid air to the first heat exchanger (17); the liquid air heated by the first liquid air storage unit (15) and transmitted to the first heat exchanger (17) acts on the turbine generator set (18) to generate electric energy as the first part of electric energy; an air separation device (20), connected to the first liquid air storage unit (15), the air separation device (20) being suitable for separating the liquid air delivered by the first liquid air storage unit (15) into oxygen and nitrogen; a second liquid air storage unit (22) connected to the air separation device (20) and the first heat exchanger (17); the second liquid air storage unit (22) is suitable for receiving liquid air remaining after the air separation device (20) separates the liquid air, and transporting the remaining liquid air to the first heat exchanger (17); the liquid air heated by the second liquid air storage unit (22) transported to the first heat exchanger (17) acts on the turbine generator set (18) to generate electric energy as the second part of electric energy; the first part of electric energy serves as a supplement to the second part of electric energy; a first filtering and purifying device (25), connected to the air separation device (20), wherein the first filtering and purifying device (25) is suitable for filtering and purifying the nitrogen separated by the air separation device (20); a liquid nitrogen distillation device (26) connected to the first filtering and purifying device (25), wherein the liquid nitrogen distillation device (26) is suitable for distilling and purifying liquid nitrogen from filtered and purified nitrogen; a liquid nitrogen storage unit (28) connected to the liquid nitrogen rectification device (26) and the second heat exchanger (30), wherein the liquid nitrogen storage unit (28) is suitable for receiving and storing liquid nitrogen delivered by the liquid nitrogen rectification device (26), and delivering the liquid nitrogen to the second heat exchanger (30); a second filtering and purifying device (33), connected to the air separation device (20), wherein the second filtering and purifying device (33) is suitable for filtering and purifying oxygen separated by the air separation device (20); A liquid oxygen distillation device (34) connected to the second filtering and purifying device (33), wherein the liquid oxygen distillation device (34) is suitable for distilling and purifying liquid oxygen from the filtered and purified oxygen; A liquid oxygen storage unit (36) is connected to the liquid oxygen distillation device (34), and the liquid oxygen storage unit (36) is suitable for receiving and storing liquid oxygen delivered by the liquid oxygen distillation device (34).

3. The green ammonia synthesis system according to claim 2, characterized in that: The air compressor unit (11) is a multi-stage compressor, and exhaust gas from each stage of the compressor passes through the first energy-saving heat exchange device (12).

4. The green ammonia synthesis system according to claim 2, characterized in that: The air compression liquefaction separation subsystem also includes: a first gas booster (27) connected between the liquid nitrogen rectification device (26) and the gas inlet of the first filtering and purifying device (25); the first gas booster (27) is suitable for boosting the pressure of the uncondensed cryogenic nitrogen and then re-transporting it to the first filtering and purifying device (25); The second gas booster (35) is connected between the liquid oxygen distillation equipment (34) and the air inlet of the second filtering and purifying device (33); the second gas booster (35) is suitable for boosting the pressure of uncondensed cryogenic oxygen and then transporting it back to the second filtering and purifying device (33).

5. The green ammonia synthesis system according to any one of claims 2 to 4, characterized in that: The water electrolysis subsystem comprises: A third filtering and purifying device (37) adapted to filter and purify the water (53); a water electrolysis device (38) connected to the third filtering and purifying device (37), wherein the water electrolysis device (38) is suitable for electrolyzing the filtered and purified water (53) into hydrogen and oxygen; a second energy-saving heat exchange device (39) connected to the water electrolysis device (38) and the steam generator (3), the second energy-saving heat exchange device (39) being adapted to receive oxygen electrolyzed by the water electrolysis device (38), heating the water medium (51) by utilizing the water electrolysis heat of the oxygen, and transporting the heated water medium (51) to the steam generator (3); a second filtering and drying device (40), connected to the second energy-saving heat exchange device (39) and the liquid oxygen distillation device (34), the second filtering and drying device (40) being adapted to receive, filter and dry the cooled oxygen, and to deliver the filtered and dried oxygen to the liquid oxygen distillation device (34); The third filtering and drying device (42) is connected to the water electrolysis device (38) and the green ammonia synthesis subsystem. The third filtering and drying device (42) is suitable for receiving, filtering and drying the hydrogen electrolyzed by the water electrolysis device (38), and transporting the filtered and dried hydrogen to the green ammonia synthesis subsystem.

6. The green ammonia synthesis system according to any one of claims 1 to 4, characterized in that: The green ammonia synthesis subsystem comprises: a synthesis gas compressor (44), connected to the second heat exchanger (30) and the water electrolysis subsystem; the synthesis gas compressor (44) is suitable for receiving nitrogen transmitted by the second heat exchanger (30) and hydrogen transmitted by the water electrolysis subsystem, and pressurizing the mixed nitrogen and hydrogen; an ammonia synthesis tower (45), connected to the synthesis gas compressor (44), the ammonia synthesis tower (45) being adapted to receive the mixed pressurized nitrogen and hydrogen to perform a synthesis reaction to generate ammonia; a gas-liquid separation device (46) connected to the ammonia synthesis tower (45), wherein the gas-liquid separation device (46) is suitable for separating liquid ammonia transported by the ammonia synthesis tower (45); a third energy-saving heat exchange device (47) connected to the gas-liquid separation device (46) and the steam generator (3); the third energy-saving heat exchange device (47) is adapted to receive the liquid ammonia separated by the gas-liquid separation device (46), heat the water medium (51) by utilizing the reaction heat of the liquid ammonia, and transport the heated water medium (51) to the steam generator (3); A liquid ammonia storage unit (49) is connected to the third energy-saving heat exchange device (47), and the liquid ammonia storage unit (49) is suitable for receiving and storing the cooled liquid ammonia delivered by the third energy-saving heat exchange device (47).

7. The green ammonia synthesis system according to claim 6, characterized in that: The gas-liquid separation device (46) is also suitable for separating the mixed gas transported by the ammonia synthesis tower (45) and transporting the mixed gas back into the ammonia synthesis tower (45), wherein the mixed gas is a mixture of ammonia, unreacted hydrogen and nitrogen.

8. The green ammonia synthesis system according to claim 6, characterized in that: According to the real-time rate of hydrogen production of the water electrolysis subsystem, the flow rate of nitrogen delivered by the second heat exchanger (30) is controlled in real time so that hydrogen and nitrogen enter the synthesis gas compressor (44) at a volume ratio of 3:

1.

9. The green ammonia synthesis system according to any one of claims 1 to 4, characterized in that: The photothermal device (1) comprises: a concentrator adapted to focus radiation from sunlight (50); Sun Tower; A heat absorbing device is arranged on the solar tower; The photothermal device (1) is suitable for focusing the radiation of sunlight (50) into a heat absorption device using a concentrator, and heating the heat storage medium using the heat absorption device.

10. The green ammonia synthesis system according to any one of claims 1 to 4, characterized in that: The second heat storage structure (6) is connected to the third heat storage structure (8) via a first valve (7).

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