A green ammonia synthesis system

Abstract

The present application relates to the technical field of renewable energy, and discloses a green ammonia synthesis system, which comprises the following steps: a light-heat device is used to heat a heat storage medium by light-heat conversion; a steam generator receives the heated heat storage medium, heats a water medium, and generates steam; a steam turbine receives the steam to do work; a generator generates electricity along with the operation of the steam turbine; a second heat storage structure receives the cooled heat storage medium; an air compression, liquefaction and separation subsystem liquefies air into liquid air, and separates the liquid air into liquid oxygen and liquid nitrogen; a first heat exchanger receives the cooled heat storage medium, and heats the liquid air into gaseous air; a second heat exchanger receives the cooled heat storage medium, and heats the liquid nitrogen into nitrogen gas; a water electrolysis subsystem decomposes water into hydrogen and oxygen; and a green ammonia synthesis subsystem receives the nitrogen and hydrogen, and synthesizes them into ammonia. The sunlight is converted into electric energy to drive the green ammonia synthesis system to operate, the heat storage medium directly provides heat energy for the liquid air and the liquid nitrogen, energy loss caused by multiple conversions is avoided, and the utilization efficiency of solar energy is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of renewable energy technology, in particular to a green ammonia synthesis system. BACKGROUND

[0002] With the increasing depletion of traditional non-renewable energy and the pollution caused by non-renewable energy to the environment, developing renewable green energy has become the focus of the energy field.

[0003] Because 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, so synthesizing ammonia has become a hot spot in the development of domestic new energy. In addition, as one of the most important chemical raw materials, ammonia not only has wide application and huge demand in the fields of chemical industry, agriculture and industry, but also has wide application and huge demand in the fields of chemical industry, agriculture and industry. Accelerating the development of ammonia synthesis technology, especially using solar photothermal technology to produce ammonia, also known as green ammonia synthesis, has become a strategic choice for China to respond to global climate change, ensure national energy supply security and realize industrial high-quality development.

[0004] Solar photothermal technology is a technology that captures and absorbs solar radiation energy and converts it into heat energy for use, which has the advantages of green environmental protection and no pollution. However, due to the intermittent fluctuation of solar energy, the energy output by the sun not only changes with time in a day, but also is affected by factors such as season, illumination and weather; however, the synthesis of ammonia is a continuous production process. Therefore, the intermittent fluctuation of solar energy and the mismatch of continuous synthesis of green ammonia.

[0005] Through continuous research and development, solar photothermal technology can be coupled with the process of synthesizing ammonia, specifically by converting heat energy into kinetic energy of a steam turbine through a steam medium to do work, driving a generator to generate electricity, and then using the generated electricity to liquefy air, separate nitrogen, electrolyze water to produce hydrogen, and synthesize green ammonia. In the above entire production process, almost no carbon emissions are generated, and because it is through the conversion of solar energy into heat energy, and then into electrical energy for power generation, it can ensure the stable output of electrical energy, overcome the mismatch between the intermittent fluctuation of solar energy and the continuous synthesis of green ammonia, and has a positive effect on 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 photothermal energy to convert solar energy into electrical energy required for the operation of the green ammonia synthesis system; from the overall process, the utilization efficiency of solar energy is not high. SUMMARY

[0007] Therefore, the green ammonia synthesis system is provided to solve the problem that the existing photothermal technology for preparing green ammonia only simply utilizes solar energy and converts the solar energy into electric energy required for the operation of the green ammonia synthesis system.

[0008] The green ammonia synthesis system comprises:

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

[0010] The photothermal device is connected with the third heat storage structure, and is adapted to convert sunlight into heat energy and heat the heat storage medium transmitted by the third heat storage structure by using the heat energy;

[0011] The first heat storage structure is connected with the photothermal device, and is adapted to receive the heated heat storage medium;

[0012] The steam generator is connected with the first heat storage structure, and is adapted to receive the heated heat storage medium and heat a water medium by using the heat storage medium to generate steam;

[0013] The steam turbine is connected with the steam generator, and is adapted to receive the steam and drive the steam turbine to work by using the steam;

[0014] The generator is connected with the steam turbine, and is adapted to generate electric energy along with the operation of the steam turbine, and then provide electric energy for the green ammonia synthesis system;

[0015] The second heat storage structure is connected with the steam generator, and is adapted to receive the heat storage medium after the first temperature drop;

[0016] The air compression, liquefaction and separation subsystem is adapted to sequentially compress and liquefy the air into liquid air, separate part of the liquid air into liquid oxygen and liquid nitrogen, and provide electric energy by using the generator;

[0017] The first heat exchanger is connected with the air compression, liquefaction and separation subsystem, the second heat storage structure and the third heat storage structure, and is adapted to receive the heat storage medium after the first temperature drop, heat part of the liquid air of the air compression, liquefaction and separation subsystem into gaseous air by using the heat storage medium after the first temperature drop, and deliver the heat storage medium after the second temperature drop to the third heat storage structure;

[0018] The turbine generator set is connected with the first heat exchanger, and is adapted to receive the gaseous air heated by the first heat exchanger to generate electric energy as a supplement of the electric energy generated by the generator;

[0019] a second heat exchanger connected with the air compression and liquefaction separation subsystem, the second heat storage structure and the photo-thermal device, the second heat exchanger being adapted to receive the once-cooled heat storage medium, heat the liquid nitrogen separated by the air compression and liquefaction separation subsystem with the once-cooled heat storage medium, vaporize the liquid nitrogen into nitrogen gas, and deliver the twice-cooled heat storage medium to the photo-thermal device to reheat the twice-cooled heat storage medium;

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

[0021] a green ammonia synthesis subsystem connected with the second heat exchanger and the water electrolysis subsystem, the green ammonia synthesis subsystem being adapted to receive the nitrogen gas heated by the second heat exchanger and the hydrogen generated by the water electrolysis subsystem, and synthesize the nitrogen gas and the hydrogen into ammonia. The present application has the following beneficial effects. On the one hand, the sunlight is converted into electric energy to drive the green ammonia synthesis system to operate. On the other hand, the heat storage medium of the heat cycle directly provides the required heat energy for the liquid air and the liquid nitrogen, avoiding the loss of energy caused by multiple 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 the sunlight is sufficient, the excess heat energy can be stored. When the sunlight is insufficient and the generated electric energy is insufficient to maintain the normal operation of the green ammonia synthesis system, the stored heat energy can be converted into electric energy for power supply, so that the entire green ammonia synthesis system can operate efficiently, and renewable energy can be effectively utilized more efficiently. When the electric energy generated by the photo-thermal technology is too much to be completely used, the electric power of the photo-thermal conversion generator is used to power the air compression and liquefaction separation subsystem, and the air stores the electric energy in the form of liquid air. When the generated electric energy 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 electric energy by a turbine generator set for the green ammonia synthesis system. That is, the green ammonia synthesis system has a certain flexibility to ensure power supply, overcome the mismatch between the intermittent and fluctuating nature of solar energy and the continuity of the ammonia synthesis process, ensure the stable operation of the green ammonia synthesis system without external power supply, and reasonably utilize the heat energy carried by the heat storage medium, further improve the energy utilization efficiency of the green ammonia synthesis system. At the same time, since 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 and liquefaction separation subsystem comprises:

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

[0024] an air compressor set connected with the first filtering and drying device, the air compressor set being adapted to compress the filtered and dried air and being powered by the generator.

[0025] The first energy-saving heat exchange device is connected with the air compressor unit and the steam generator, and is adapted to heat the water medium by using the compression heat of the air compression process and deliver the heated water medium to the steam generator;

[0026] The liquid air condensing tower is connected with the first energy-saving heat exchange device, and is adapted to condense and cool the compressed and cooled air into liquid air;

[0027] The first liquid air storage unit is connected with the liquid air condensing tower and the first heat exchanger, and is adapted to receive and store the liquid air and 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 is heated to generate the first part of electric energy for the turbine generator unit;

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

[0029] The second liquid air storage unit is connected with the air separation device and the first heat exchanger, and is adapted to receive the remaining liquid air after the air separation device separates the liquid air and 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 is heated to generate the second part of electric energy for the turbine generator unit; the first part of electric energy is supplementary to the second part of electric energy;

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

[0031] The liquid nitrogen rectification equipment is connected with the first filtering and purifying device, and is adapted to rectify and purify the filtered and purified nitrogen to obtain liquid nitrogen;

[0032] The liquid nitrogen storage unit is connected with the liquid nitrogen rectification equipment and the second heat exchanger, and is adapted to receive and store the liquid nitrogen delivered by the liquid nitrogen rectification equipment and deliver the liquid nitrogen to the second heat exchanger;

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

[0034] The liquid oxygen rectification equipment is connected with the second filtering and purifying device, and is adapted to rectify and purify the filtered and purified oxygen to obtain liquid oxygen;

[0035] The liquid oxygen storage unit is connected with the liquid oxygen rectification device, and is adapted to receive and store the liquid oxygen delivered by the liquid oxygen rectification device. Advantage: the application uses the above technical solution to recycle the compression heat by using the first energy-saving heat exchange device, and provides heat energy for the steam generator by preheating the water medium, so as to improve the temperature of the water medium used in the steam generator. The preheated water medium is changed into steam after heat exchange with the heat storage medium, and drives the generator to generate electricity by the gas turbine. In the process of heat exchange between the water medium used in the steam generator and the first energy-saving heat exchange device, the preheated water medium with high temperature is obtained, and the compressed air is cooled. Moreover, the air compression and liquefaction sub-system not only obtains the nitrogen required for green ammonia production, but also produces by-products such as liquid nitrogen and liquid oxygen, which can be sold separately, so as to improve economic benefits and reduce costs. When the power generated by the generator is insufficient to maintain the operation of the green ammonia synthesis system, the second part of the power can be used to supplement the operation of the green ammonia synthesis system, and when the second part of the power is insufficient to maintain the operation of the green ammonia synthesis system, the first part of the power can be used to supplement the operation of the green ammonia synthesis system.

[0036] Optionally, the air compressor set is a multi-stage compressor, and the exhaust of each stage of compressor passes through the first energy-saving heat exchange device. Advantage: the application uses the above technical solution to fully utilize the compression heat to heat the water medium.

[0037] Optionally, the air compression and liquefaction sub-system further comprises:

[0038] The first gas booster is connected between the liquid nitrogen rectification device and the gas inlet of the first filter and purifier, and is adapted to pressurize the uncondensed cryogenic nitrogen and then re-deliver it into the first filter and purifier.

[0039] The second gas booster is connected between the liquid oxygen rectification device and the gas inlet of the second filter and purifier, and is adapted to pressurize the uncondensed cryogenic oxygen and then re-deliver it into the second filter and purifier. Advantage: the application uses the above technical solution to provide nitrogen raw material and cold supplement for the liquid nitrogen rectification device by the first gas booster, so as to save energy and improve the conversion rate. The second gas booster provides oxygen raw material and cold supplement for the liquid oxygen rectification device, so as to save energy and improve the conversion rate.

[0040] Optionally, the water electrolysis sub-system comprises:

[0041] The third filter and purifier is adapted to filter and purify the water.

[0042] The water electrolysis device is connected with the third filter and purifier, and is adapted to electrolyze the filtered and purified water into hydrogen and oxygen.

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

[0044] The second filtering and drying device is connected with the second energy-saving heat exchange device and the liquid oxygen rectification equipment, and is adapted to receive, filter and dry the cooled oxygen, and deliver the filtered and dried oxygen to the liquid oxygen rectification equipment.

[0045] The third filtering and drying device is connected with the water electrolysis device and the green ammonia synthesis subsystem, and is adapted to receive, filter and dry hydrogen electrolyzed by the water electrolysis device, and deliver the filtered and dried hydrogen to the green ammonia synthesis subsystem. The application has the beneficial effects that: the second energy-saving heat exchange device is used to recycle water electrolysis heat of the oxygen, and the preheated water medium is integrated into the steam generator to provide heat energy for the steam generator, so that the temperature of the water medium used in the steam generator is increased, and the preheated water medium is changed into steam after heat exchange of the heat storage medium, and drives the generator to generate electricity through the gas turbine. In the process of heat exchange between the water medium used in the steam generator and the second energy-saving heat exchange device, the preheated water medium with a high temperature is obtained, and the oxygen is cooled. In addition, the water electrolysis subsystem cancels the hydrogen storage unit, and the hydrogen continuously enters the green ammonia synthesis subsystem, so that the water electrolysis subsystem is efficiently produced. Meanwhile, the liquid oxygen in the liquid oxygen rectification equipment and the oxygen can be sold as by-products, so that the economic benefit is improved, and the cost is reduced. In addition, the water electrolysis heat in the hydrogen can provide heat for subsequent reactions, so that the energy-saving effect is further achieved.

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

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

[0048] The ammonia synthesis tower is connected with the synthesis gas compressor, and is adapted to receive the mixed pressurized nitrogen gas and hydrogen gas, and perform a synthesis reaction to generate ammonia gas.

[0049] The gas-liquid separation device is connected with the ammonia synthesis tower, and is adapted to separate liquid ammonia delivered by the ammonia synthesis tower.

[0050] A third energy-saving heat exchange device is connected with the gas-liquid separation device and the steam generator, and is adapted to receive the liquid ammonia separated by the gas-liquid separation device, heat the water medium by using the reaction heat of the liquid ammonia, and deliver the heated water medium to the steam generator;

[0051] A liquid ammonia storage unit is connected with the third energy-saving heat exchange device, and is adapted to receive and store the cooled liquid ammonia delivered by the third energy-saving heat exchange device.

[0052] Optionally, the gas-liquid separation device is further adapted to separate the mixed gas delivered by the ammonia synthesis tower, and deliver the mixed gas into the ammonia synthesis tower again, the mixed gas being a mixture of ammonia, unreacted hydrogen and nitrogen.

[0053] Optionally, the flow of the nitrogen delivered by the second heat exchanger is controlled in real time according to the real-time rate of hydrogen production of the water electrolysis subsystem, so that the hydrogen and the nitrogen enter the synthesis gas compressor at a volume ratio of 3:1.

[0054] Optionally, the photo-thermal device comprises:

[0055] A light concentrator adapted to focus the radiation of sunlight;

[0056] A solar tower;

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

[0058] The light-thermal equipment is suitable for focusing the sunlight radiation into the heat-absorbing device by a condenser, and heating the heat storage medium by the heat-absorbing device.

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

[0060] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0061] Figure 1 The connection diagram of the green ammonia synthesis system provided in the embodiments of the present application.

[0062] Explanation of reference signs:

[0063] 1, light-thermal 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 filtering and drying device; 11, air compressor unit; 12, first energy-saving heat exchange device; 13, third valve; 14, liquid air condensing tower; 15, first liquid air storage unit; 16, fourth valve; 17, first heat exchanger; 18, turbine generator unit; 19, fifth valve; 20, air separation device; 21, sixth valve; 22, second liquid air storage unit; 23, seventh valve; 24, eighth valve; 25, first filtering and purifying device; 26, liquid nitrogen rectification equipment; 27, first gas booster; 28, liquid nitrogen storage unit; 29, ninth valve; 30, second heat exchanger; 31, tenth valve; 32, eleventh valve; 33, second filtering and purifying device; 34, liquid oxygen rectification equipment; 35, second gas booster; 36, liquid oxygen storage unit; 37, third filtering and purifying device; 38, electrolytic water device; 39, second energy-saving heat exchange device; 40, second filtering and drying device; 41, twelfth valve; 42, third filtering and drying device; 43, thirteenth valve; 44, synthesis gas compressor; 45, ammonia synthesis tower; 46, gas-liquid separation device; 47, third energy-saving heat exchange device; 48, fourteenth valve; 49, liquid ammonia storage unit; 50, sunlight; 51, water medium; 52, air; 53, water. DETAILED DESCRIPTION

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] Existing processes for producing green ammonia generate significant waste heat during raw material production and synthesis, which is released into the environment, resulting in substantial energy waste. Furthermore, due to the intermittent nature of solar energy, energy storage systems are required for combined solar energy utilization, significantly increasing the cost of green ammonia synthesis and failing to fully couple solar thermal technology with the green ammonia synthesis system. For these reasons, this application proposes a green ammonia synthesis system.

[0066] like Figure 1 A specific embodiment of the green ammonia synthesis system shown includes: a third thermal storage structure 8, a solar thermal device 1, a first thermal storage structure 2, a steam generator 3, a steam turbine 4, a generator 5, a second thermal storage structure 6, an air compression liquefaction and 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 this application is based on solar thermal technology and features low energy consumption. This system truly achieves bidirectional coupling between solar thermal storage and ammonia synthesis, not only realizing zero carbon emissions throughout the entire green ammonia synthesis process but also maximizing the utilization of solar energy, reducing energy loss, improving the production efficiency and energy utilization efficiency of green ammonia, lowering costs, improving economic efficiency, promoting the consumption of renewable energy, meeting environmental protection and energy storage needs, creating considerable social and economic benefits, and providing certain insights for future industrial production structures. 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, which 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 heat storage medium, specifically, the heat storage medium can be in molten state inorganic salt. The photo-thermal device 1 is connected with the third heat storage structure 8, the photo-thermal device 1 is suitable for converting sunlight 50 into heat energy, and the heat energy is used to heat the heat storage medium transmitted by the third heat storage structure 8. The first heat storage structure 2 is connected with the photo-thermal device 1, and the first heat storage structure 2 is suitable for receiving the heated heat storage medium. The steam generator 3 is connected with the first heat storage structure 2, and the steam generator 3 is suitable for receiving the heated heat storage medium and heating the water medium 51 by using the heat storage medium to generate steam. The steam turbine 4 is connected with the steam generator 3, and the steam turbine 4 is suitable for receiving steam and driving the steam turbine 4 to work by using the steam. The generator 5 is connected with the steam turbine 4, and the generator 5 is suitable for generating electricity with the steam turbine 4, thereby providing electric energy for the green ammonia synthesis system. The second heat storage structure 6 is connected with the steam generator 3; the second heat storage structure 6 is suitable for receiving the heat storage medium cooled once. The second heat storage structure 6 can be connected with the third heat storage structure 8 through the first valve 7.

[0068] The air compression, liquefaction and separation subsystem is suitable for sequentially compressing and liquefying the air 52 into liquid air, and separating part of the liquid air into liquid oxygen and liquid nitrogen, and providing electric energy for the air compression, liquefaction and separation subsystem by the generator 5. The first heat exchanger 17 is connected with the air compression, liquefaction and separation subsystem, the second heat storage structure 6 and the third heat storage structure 8, and the first heat exchanger 17 is suitable for receiving the heat storage medium cooled once, heating part of the liquid air of the air compression, liquefaction and separation subsystem into gaseous air by using the heat storage medium cooled once, and delivering the heat storage medium cooled twice to the third heat storage structure 8. The second valve 9 is arranged between the first heat exchanger 17 and the second heat storage structure 6. The turbine generator set 18 is connected with 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 of the electric energy generated by the generator 5. The second heat exchanger 30 is connected with the air compression, liquefaction and separation subsystem, the second heat storage structure 6 and the photo-thermal device 1, and the second heat exchanger 30 is suitable for receiving the heat storage medium cooled once, heating the liquid nitrogen separated by the air compression, liquefaction and separation subsystem into nitrogen gas by using the heat storage medium cooled once, and delivering the heat storage medium cooled twice to the photo-thermal device 1 to reheat the heat storage medium cooled twice. The tenth valve 31 is arranged between the second heat exchanger 30 and the second heat storage structure 6.

[0069] The water electrolysis subsystem is adapted to decompose water 53 into hydrogen and oxygen. The green ammonia synthesis subsystem is connected with the second heat exchanger 30 and the water electrolysis subsystem, and is adapted to receive the heated nitrogen gas of the second heat exchanger 30 and the hydrogen generated by the water electrolysis subsystem, and synthesize the nitrogen gas and the hydrogen into ammonia.

[0070] Specifically, the air compression, liquefaction and separation subsystem includes a first filtering and drying device 10, an air compressor set 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 equipment 26, a liquid nitrogen storage unit 28, a second filtering and purifying device 33, a liquid oxygen rectification equipment 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 be liquid air storage tanks.

[0071] The first filtering and drying device 10 is adapted to filter and dry the air 52. The air compressor set 11 is connected with the first filtering and drying device 10, and is adapted to compress the filtered and dried air, and the air compressor set 11 is provided with electric energy by the generator 5. The first energy-saving heat exchange device 12 is connected with the air compressor set 11 and the steam generator 3, and is adapted to heat the water medium 51 by using the compression heat of the air compression process, and deliver the heated water medium 51 to the steam generator 3. Further, the air compressor set 11 is a multi-stage compressor, and the exhaust of each stage of compressor passes through the first energy-saving heat exchange device 12.

[0072] The liquid air condensing tower 14 is connected with the first energy-saving heat exchange device 12, and is adapted to condense and cool the compressed and cooled air into liquid air. A third valve 13 is arranged between the liquid air condensing tower 14 and the first energy-saving heat exchange device 12. The first liquid air storage unit 15 is connected with the first heat exchanger 17 of the liquid air condensing tower 14, and is adapted to receive and store liquid air and deliver part of the liquid air to the first heat exchanger 17. The first liquid air storage unit 15 delivers the heated liquid air to the turbine generator set 18 to generate the first part of electric energy. A fourth valve 16 is arranged between the first liquid air storage unit 15 and the first heat exchanger 17. The air separation device 20 is connected with the first liquid air storage unit 15, and is adapted to separate the liquid air delivered by the first liquid air storage unit 15 into oxygen and nitrogen. A fifth valve 19 is arranged between the air separation device 20 and the first liquid air storage unit 15. The second liquid air storage unit 22 is connected with the air separation device 20 and the first heat exchanger 17, and is adapted to receive the remaining liquid air after the air separation device 20 separates the liquid air and deliver the remaining liquid air to the first heat exchanger 17. A sixth valve 21 is arranged 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 arranged between the second liquid air storage unit 22 and the first heat exchanger 17. The second liquid air storage unit 22 delivers the heated liquid air to the turbine generator set 18 to generate the second part of electric energy. The first part of electric energy is supplementary to the second part of electric energy. The first filtering and purifying device 25 is connected with the air separation device 20, and is adapted to filter and purify the nitrogen separated by the air separation device 20. An eighth valve 24 is arranged between the nitrogen outlet of the air separation device 20 and the first filtering and purifying device 25. The liquid nitrogen rectification equipment 26 is connected with the first filtering and purifying device 25, and is adapted to rectify and purify the filtered and purified nitrogen to obtain liquid nitrogen. The liquid nitrogen is high-purity low-temperature liquid nitrogen. The liquid nitrogen rectification equipment 26 is a liquid nitrogen high-pressure rectification equipment. A liquid nitrogen storage unit 28 is connected with the liquid nitrogen rectification equipment 26 and the second heat exchanger 30, and is adapted to receive and store the liquid nitrogen delivered by the liquid nitrogen rectification equipment 26 and deliver the liquid nitrogen to the second heat exchanger 30. A ninth valve 29 is arranged 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 according to needs. The second filtering and purifying device 33 is connected with the air separation device 20, and is adapted to filter and purify the oxygen separated by the air separation device 20.A eleventh valve 32 is arranged between the oxygen outlet of the air separation device 20 and the second filtering and purifying device 33. The liquid oxygen rectification equipment 34 is connected to the second filtering and purifying device 33, and the liquid oxygen rectification equipment 34 is adapted to rectify and purify the filtered and purified oxygen to obtain liquid oxygen. The liquid oxygen rectification equipment 34 is a high-pressure liquid oxygen rectification equipment, and a liquid oxygen storage unit 36 is connected to the liquid oxygen rectification equipment 34, and the liquid oxygen storage unit 36 is adapted to receive and store the liquid oxygen delivered by the liquid oxygen rectification equipment 34.

[0073] The first gas booster 27 is connected between the liquid nitrogen rectification equipment 26 and the gas inlet of the first filtering and purifying device 25, and the first gas booster 27 is adapted to boost the uncondensed cryogenic nitrogen and re-deliver it into the first filtering and purifying device 25. The second gas booster 35 is connected between the liquid oxygen rectification equipment 34 and the gas inlet of the second filtering and purifying device 33, and the second gas booster 35 is adapted to boost the uncondensed cryogenic oxygen and re-deliver it into the second filtering and purifying device 33.

[0074] Specifically, the water electrolysis subsystem includes a third filtering and purifying device 37, an electrolytic water device 38, a second energy-saving heat exchanger 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 adapted to filter and purify the water 53. The electrolytic water device 38 is connected to the third filtering and purifying device 37, and the electrolytic water device 38 is adapted to electrolyze the filtered and purified water 53 into hydrogen and oxygen. The second energy-saving heat exchanger 39 is connected to the electrolytic water device 38 and the steam generator 3, and the second energy-saving heat exchanger 39 is adapted to receive the oxygen electrolyzed by the electrolytic water device 38, heat the water medium 51 using the water electrolysis heat of the oxygen, and deliver 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 exchanger 39 and the liquid oxygen rectification equipment 34, and the second filtering and drying device 40 is adapted to receive, filter, and dry the cooled oxygen, and deliver the filtered and dried oxygen to the liquid oxygen rectification equipment 34. A twelfth valve 41 is arranged between the second filtering and drying device 40 and the liquid oxygen rectification equipment 34. The third filtering and drying device 42 is connected to the electrolytic water device 38 and the green ammonia synthesis subsystem, and the third filtering and drying device 42 is adapted to receive, filter, and dry the hydrogen electrolyzed by the electrolytic water device 38, and deliver the filtered and dried hydrogen to the green ammonia synthesis subsystem. A thirteenth valve 43 is arranged between the third filtering and drying device 42 and the green ammonia synthesis subsystem.

[0076] Specifically, the green ammonia synthesis subsystem comprises 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 with the second heat exchanger 30 and the water electrolysis subsystem. The synthesis gas compressor 44 is adapted to receive the nitrogen gas transmitted by the second heat exchanger 30 and the hydrogen gas transmitted by the third filtering and drying device 42 of the water electrolysis subsystem, and pressurize the mixed nitrogen gas and hydrogen gas. Further, according to the real-time rate of hydrogen production of the water electrolysis subsystem, the flow rate of the nitrogen gas delivered by the second heat exchanger 30 is controlled in real time, so that the hydrogen gas and the nitrogen gas enter the synthesis gas compressor 44 at a volume ratio of 3:1.

[0078] The ammonia synthesis tower 45 is connected with the synthesis gas compressor 44. The ammonia synthesis tower 45 is adapted to receive the mixed pressurized nitrogen gas and hydrogen gas, and perform a synthesis reaction to generate ammonia gas. The gas-liquid separation device 46 is connected with the ammonia synthesis tower 45. The gas-liquid separation device 46 is adapted to separate the liquid ammonia delivered by the ammonia synthesis tower 45. Further, the gas-liquid separation device 46 is also adapted to separate the mixed gas delivered by the ammonia synthesis tower 45, and re-deliver the mixed gas to the ammonia synthesis tower 45. The mixed gas is a mixture of ammonia gas, unreacted hydrogen gas, and nitrogen gas.

[0079] The third energy-saving heat exchange device 47 is connected with 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 using the reaction heat of the liquid ammonia, and deliver the heated water medium 51 to the steam generator 3. The liquid ammonia storage unit 49 is connected with the third energy-saving heat exchange device 47. The liquid ammonia storage unit 49 is adapted to receive and store the cooled liquid ammonia delivered by the third energy-saving heat exchange device 47. A fourteenth valve 48 is arranged between the liquid ammonia storage unit 49 and the third energy-saving heat exchange device 47.

[0080] Specifically, the photo-thermal device 1 comprises a light concentrator, a solar tower, and a heat absorption device. The light concentrator is adapted to focus the radiation of sunlight 50. The heat absorption device is arranged on the top of the solar tower. The photo-thermal device 1 is adapted to focus the radiation of sunlight 50 into the heat absorption device by the light concentrator, and heat the heat storage medium by 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 light and heat equipment 1, the heat storage medium enters the first heat storage structure 2 at a temperature of 480-550°C, 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, heats the water medium 51 in the steam generator 3 which has been preheated into steam, the steam is introduced into the steam inlet of the steam turbine 4 from the steam outlet of the steam generator 3 through a pipeline, drives the steam turbine 4 to work, the steam turbine 4 is coaxially connected with 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 transported into the second heat storage structure 6; the temperature in the second heat storage structure 6 is between 300-350°C.

[0082] The working medium heat exchange outlet of the second heat storage structure 6 is connected with the working medium heat exchange inlet of the third heat storage structure 8 through a pipeline and the first valve 7; the second heat storage structure 6 is connected with the working medium heat exchange inlet of the first heat exchanger 17 through a pipeline and the second valve 9; the second heat storage structure 6 is connected with the working medium heat exchange inlet of the second heat exchanger 30 through a pipeline and the tenth valve 31. The third heat storage structure 8 is connected with the working medium heat exchange outlet of the first heat exchanger 17 through a pipeline. After heat release, the heat storage medium enters the third heat storage structure 8, and the temperature of the heat storage medium is between 150-220°C. The third heat storage structure 8 is connected with the working medium heat exchange inlet of the light and heat equipment 1 through a pipeline, reabsorbs the heat generated by the solar energy in the light and heat equipment 1, and prepares for a new round of circulation.

[0083] The raw air 52 is first filtered and dried by the first filtering and drying device 10, then sent into the air compressor set 11 for compression, the air compressor set 11 includes multiple integrated multi-stage compressors, the multiple-stage compressors are split shafts, and each split shaft is connected with the main drive shaft in parallel, the exhaust gas of each stage of compressor passes through the first energy-saving heat exchange device 12. The raw air 52 at normal temperature and pressure is filtered and dried, compressed to a high-pressure and high-temperature state by the air compressor set 11, cooled in the first energy-saving heat exchange device 12, the first energy-saving heat exchange device 12 is provided with a feed water inlet connected with the water medium 51 conveying pipeline, 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 water medium 51 conveying pipeline, the water medium 51 in the first energy-saving heat exchange device 12 is further heated into steam after recovering the heat generated in the compression process of the air 52, and the raw air 52 becomes normal-temperature and high-pressure state at this time; the normal-temperature and high-pressure air 52 discharged from the first energy-saving heat exchange device 12 enters the liquid air condensing tower 14 after passing through the third valve 13, is condensed and cooled into liquid air, and finally is sent into 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, is converted from liquid to gas by absorbing the heat of the heat storage medium in the first heat exchanger 17, and is converted from the stored molecular potential energy to power by the turbine action of the turbine generator set 18, drives the dedicated generator of the turbine generator set 18 to generate electricity, and applies the electricity to the entire green ammonia synthesis system; especially when the electricity produced 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 almost exhausted, the electricity generated by the turbine generator set 18 serves 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 electricity produced by the generator 5 is surplus and sufficient to bear the entire green ammonia synthesis system, part of the electricity can be used for the air compressor set 11 and the like to perform liquid treatment on the external air 52, and store the liquid air in the first liquid air storage unit 15; when the electricity produced by the generator 5 is insufficient to completely bear the operation of the entire green ammonia synthesis system, and the liquid air in the second liquid air storage unit 22 is almost exhausted, the liquid air in the first liquid air storage unit 15 can be converted into gaseous air to perform energy conversion, the energy is converted into the power of the turbine generator set 18 to generate electricity, and the electricity is 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 to be processed into oxygen, nitrogen and remaining liquid gas. The remaining liquid gas separated by the air separation device 20 is stored in the second liquid air storage unit 22 through the sixth valve 21, and the second liquid air storage unit 22 is connected to the first heat exchanger 17 through the seventh valve 23. When the electricity produced 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, absorbs the heat of the heat storage medium to vaporize, and 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 filter purification device 25, and then enters the liquid nitrogen rectification equipment 26 for rectification and purification. The nitrogen is separated into cryogenic nitrogen and high-purity liquid nitrogen. The high-purity liquid nitrogen is discharged from the separated liquid outlet and stored in the liquid nitrogen storage unit 28. The uncondensed cryogenic nitrogen is discharged from the separated gas outlet, enters the branch pipeline, is pressurized by the first gas booster 27, is treated by the first filter purification device 25 again, and then reenters the liquid nitrogen rectification equipment 26 to provide nitrogen raw material and cold supplement for the liquid nitrogen rectification equipment 26, 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. The liquid nitrogen absorbs the heat of the heat storage medium and is vaporized into high-temperature nitrogen gas, which enters the synthesis gas compressor 44. The heat storage medium after heat exchange enters the light-heat equipment 1.

[0088] The oxygen separated by the air separation device 20 is purified by the eleventh valve 32 and the second filter purification device 33, and then enters the liquid oxygen rectification equipment 34 for rectification and purification. The oxygen is separated into cryogenic oxygen and high-purity liquid oxygen. The high-purity liquid oxygen is discharged from the separated liquid outlet and stored in the liquid oxygen storage unit 36. The uncondensed cryogenic oxygen is discharged from the separated gas outlet, enters the branch pipeline, is pressurized by the second gas booster 35, is treated by the second filter purification device 33 again, and then reenters the liquid oxygen rectification equipment 34 to provide oxygen raw material and cold supplement for the liquid oxygen rectification equipment 34, so as to save energy and improve the conversion rate.

[0089] The external water 53 is purified by the third filter purification device 37, and then subjected to water electrolysis reaction by the electrolytic water device 38 to obtain hydrogen and oxygen. The oxygen is discharged from the oxygen outlet of the electrolytic water device 38, enters the second energy-saving heat exchanger 39, and exchanges heat with the water medium 51 entering from the water inlet. The water medium 51 is further heated into steam by the steam generator 3 after absorbing the water electrolysis heat of the oxygen. The oxygen in the second energy-saving heat exchanger 39 is cooled by heat exchange, passes through the second filter drying device 40 and the twelfth valve 41 in sequence, and is combined with the oxygen generated by the air separation device 20 to enter the liquid oxygen rectification equipment 34 for rectification. Finally, the oxygen is discharged from the separated liquid outlet and stored in the liquid oxygen storage unit 36.

[0090] The hydrogen gas with electrolytic heat generated by the water electrolysis device 38 is discharged from the hydrogen gas outlet, passes through the third filtering and drying device 42 and the thirteenth valve 43, enters the synthesis gas compressor 44, is mixed with high-temperature nitrogen gas at a ratio of 3:1, and is lifted to a reaction pressure to obtain high-temperature synthesis gas; the high-temperature synthesis gas is discharged from the outlet of the synthesis gas compressor 44 and is transmitted to the mixed gas inlet of the ammonia synthesis tower 45, and an ammonia synthesis reaction is carried out in the ammonia synthesis tower 45 to generate ammonia gas; 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 and is separated by the gas-liquid separation device 46 into mixed gas and liquid ammonia; 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 is returned to the ammonia synthesis tower 45 again, the mixed gas contains part of unreacted hydrogen and nitrogen and ammonia obtained by synthesis, provides ammonia gas for the ammonia synthesis tower 45, and unreacted hydrogen, nitrogen and other raw materials and heat are supplemented to promote the conversion rate, save energy and fully utilize raw materials.

[0091] The liquid ammonia separated by the gas-liquid separation device 46 is discharged from the liquid outlet, enters the liquid ammonia inlet of the third energy-saving heat exchange device 47, and the third energy-saving heat exchange device 47 is provided with a feed water inlet; water medium 51 enters the third energy-saving heat exchange device 47 and exchanges heat with the liquid ammonia; the liquid ammonia is cooled in the third energy-saving heat exchange device 47, and 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, and the water medium 51 is further heated into steam after absorbing the synthesis reaction heat of the liquid ammonia; the liquid ammonia in the third energy-saving heat exchange device 47 is cooled by heat exchange and is stored in the liquid ammonia storage unit 49 under the control of the fourteenth valve 48.

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

[0093] η=ΔH 氨气 / QL (1)

[0094] Wherein ΔH 氨气 is the heat of combustion of unit mass of ammonia gas, and the unit is kJ / kg; QL is the total amount of solar energy received by the green ammonia synthesis system.

[0095] It has been verified that when 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 about 4.3% higher than the energy conversion efficiency of the existing system in which the photo-thermal subsystem and the green ammonia synthesis subsystem operate independently. If 2 tons of water are consumed for every ton of green ammonia produced, about 2.85*106 kJ ~ 3.12 x 10 6 kJ of energy saving. In addition, the technical scheme of the present application sets up an air compression liquefaction and separation subsystem, uses liquid air energy storage, does not need to additionally build a special energy storage system, cancels the hydrogen storage unit, controls the flow of nitrogen gas delivered by the second heat exchanger 30 in real time according to the real-time rate of hydrogen production of the water electrolysis subsystem, replaces the design of the previous hydrogen storage equipment, and not only reduces the safety risk, but also reduces the cost.

[0096] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A green ammonia synthesis system, characterized by, The system comprises: a third heat storage structure (8) storing heat storage medium; a photo-thermal device (1) connected with the third heat storage structure (8), the photo-thermal device (1) being adapted to convert sunlight (50) into heat energy, and use the heat energy to heat the heat storage medium delivered by the third heat storage structure (8); a first heat storage structure (2) connected with the photo-thermal device (1), the first heat storage structure (2) being adapted to receive the heated heat storage medium; a steam generator (3) connected with the first heat storage structure (2), the steam generator (3) being adapted to receive the heated heat storage medium, and use the heat storage medium to heat water medium (51) to generate steam; a steam turbine (4) connected with the steam generator (3), the steam turbine (4) being adapted to receive the steam, and use the steam to drive the steam turbine (4) to work; a generator (5) connected with the steam turbine (4), the generator (5) being adapted to generate electricity along with the operation of the steam turbine (4), and provide electric energy for a green ammonia synthesis system; a second heat storage structure (6) connected with the steam generator (3), the second heat storage structure (6) being adapted to receive the heat storage medium cooled once; an air compression, liquefaction and separation sub-system adapted to sequentially compress and liquefy the air (52) into liquid air, and separate part of the liquid air into liquid oxygen and liquid nitrogen, and provide electric energy by the generator (5); a first heat exchanger (17) connected with the air compression, liquefaction and separation sub-system, the second heat storage structure (6) and the third heat storage structure (8), the first heat exchanger (17) being adapted to receive the heat storage medium cooled once, use the heat storage medium cooled once to heat part of the liquid air of the air compression, liquefaction and separation sub-system into gaseous air, and deliver the heat storage medium cooled twice to the third heat storage structure (8); a turbine generator set (18) connected with 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, and supplement the electric energy generated by the generator (5); a second heat exchanger (30) connected with the air compression, liquefaction and separation sub-system, the second heat storage structure (6) and the photo-thermal device (1), the second heat exchanger (30) being adapted to receive the heat storage medium cooled once, use the heat storage medium cooled once to heat the liquid nitrogen separated by the air compression, liquefaction and separation sub-system into nitrogen gas, and deliver the heat storage medium cooled twice to the photo-thermal device (1) to reheat the heat storage medium cooled twice; a water electrolysis sub-system adapted to decompose water (53) into hydrogen and oxygen; a green ammonia synthesis sub-system connected with the second heat exchanger (30) and the water electrolysis sub-system, the green ammonia synthesis sub-system being adapted to receive the nitrogen gas heated by the second heat exchanger (30) and the hydrogen generated by the water electrolysis sub-system, and synthesize the nitrogen gas and the hydrogen into ammonia; the air compression, liquefaction and separation sub-system comprises: a first filtering and drying device (10) adapted to filter and dry the air (52); An air compressor unit (11) is connected with the first filtering and drying device (10), and is adapted to compress the filtered and dried air and provide electric energy for the air compressor unit (11) by the generator (5); A first energy-saving heat exchange device (12) is connected with the air compressor unit (11) and the steam generator (3), and is adapted to heat the water medium (51) by using the compression heat of the air compression process, and deliver the heated water medium (51) to the steam generator (3); A liquid air condensing tower (14) is connected with the first energy-saving heat exchange device (12), and is adapted to condense and cool the compressed and cooled air into liquid air; A first liquid air storage unit (15) is connected with the liquid air condensing tower (14) and the first heat exchanger (17), and is adapted to receive and store the liquid air, and deliver part of the liquid air to the first heat exchanger (17); the liquid air heated by the first liquid air storage unit (15) delivered to the first heat exchanger (17) is used to generate the first part of electric energy for the turbine generator unit (18); An air separation device (20) is connected with the first liquid air storage unit (15), and is adapted to separate the liquid air delivered by the first liquid air storage unit (15) into oxygen and nitrogen; A second liquid air storage unit (22) is connected with the air separation device (20) and the first heat exchanger (17), and is adapted to receive the remaining liquid air after the air separation device (20) separates the liquid air, and deliver the remaining liquid air to the first heat exchanger (17); the liquid air heated by the second liquid air storage unit (22) delivered to the first heat exchanger (17) is used to generate the second part of electric energy for the turbine generator unit (18); the first part of electric energy is used as a supplement of the second part of electric energy; A first filtering and purifying device (25) is connected with the air separation device (20), and is adapted to filter and purify the nitrogen separated by the air separation device (20); A liquid nitrogen rectification device (26) is connected with the first filtering and purifying device (25), and is adapted to rectify and purify the filtered and purified nitrogen to obtain liquid nitrogen; A liquid nitrogen storage unit (28) is connected with the liquid nitrogen rectification device (26) and the second heat exchanger (30), and is adapted to receive and store the liquid nitrogen delivered by the liquid nitrogen rectification device (26), and deliver the liquid nitrogen to the second heat exchanger (30); A second filtering and purifying device (33) is connected with the air separation device (20), and is adapted to filter and purify the oxygen separated by the air separation device (20); A liquid oxygen rectification device (34) is connected with the second filtering and purifying device (33), and is adapted to rectify and purify the filtered and purified oxygen to obtain liquid oxygen; A liquid oxygen storage unit (36) is connected with the liquid oxygen rectification device (34), and the liquid oxygen storage unit (36) is adapted to receive the liquid oxygen delivered by the liquid oxygen rectification device (34); The air compression and liquefaction sub-system further comprises: A first gas booster (27) is connected between the liquid nitrogen rectification device (26) and the air inlet of the first filtering and purifying device (25), and the first gas booster (27) is adapted to pressurize the uncondensed cryogenic nitrogen and then deliver it into the first filtering and purifying device (25); A second gas booster (35) is connected between the liquid oxygen rectification device (34) and the air inlet of the second filtering and purifying device (33), and the second gas booster (35) is adapted to pressurize the uncondensed cryogenic oxygen and then deliver it into the second filtering and purifying device (33); The green ammonia synthesis sub-system comprises: A synthesis gas compressor (44) is connected with the second heat exchanger (30) and the water electrolysis sub-system, and the synthesis gas compressor (44) is adapted to receive the nitrogen delivered by the second heat exchanger (30) and the hydrogen delivered by the water electrolysis sub-system, and pressurize the mixed nitrogen and hydrogen; An ammonia synthesis tower (45) is connected with the synthesis gas compressor (44), and the ammonia synthesis tower (45) is adapted to receive the mixed and pressurized nitrogen and hydrogen, and generate ammonia through a synthesis reaction; A gas-liquid separation device (46) is connected with the ammonia synthesis tower (45), and the gas-liquid separation device (46) is adapted to separate the liquid ammonia delivered by the ammonia synthesis tower (45); A third energy-saving heat exchange device (47) is connected with the gas-liquid separation device (46) and the steam generator (3), and 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 using the reaction heat of the liquid ammonia, and deliver the heated water medium (51) to the steam generator (3); A liquid ammonia storage unit (49) is connected with the third energy-saving heat exchange device (47), and the liquid ammonia storage unit (49) is adapted to receive and store the cooled liquid ammonia delivered by the third energy-saving heat exchange device (47); The gas-liquid separation device (46) is further adapted to separate the mixed gas delivered by the ammonia synthesis tower (45), and deliver the mixed gas into the ammonia synthesis tower (45) again, wherein the mixed gas is a mixture of ammonia, unreacted hydrogen and nitrogen.

2. The green ammonia synthesis system of claim 1, wherein, The air compressor set (11) is a multi-stage compressor, and the exhaust of each stage of compressor passes through the first energy-saving heat exchange device (12).

3. The green ammonia synthesis system according to claim 1 or 2, characterized in that, The water electrolysis sub-system comprises: A third filtering and purifying device (37) is adapted to filter and purify the water (53); An electrolytic water device (38) is connected with the third filtering and purifying device (37), and the electrolytic water device (38) is adapted to electrolyze the filtered and purified water (53) into hydrogen and oxygen. A second energy-saving heat exchange device (39) is connected with the electrolytic water device (38) and the steam generator (3), and is adapted to receive oxygen electrolyzed by the electrolytic water device (38), heat a water medium (51) by using water electrolysis heat of the oxygen, and deliver the heated water medium (51) to the steam generator (3); A second filtering and drying device (40) is connected with the second energy-saving heat exchange device (39) and the liquid oxygen rectification equipment (34), and is adapted to receive, filter and dry the cooled oxygen, and deliver the filtered and dried oxygen to the liquid oxygen rectification equipment (34); A third filtering and drying device (42) is connected with the electrolytic water device (38) and the green ammonia synthesis subsystem, and is adapted to receive, filter and dry hydrogen electrolyzed by the electrolytic water device (38), and deliver the filtered and dried hydrogen to the green ammonia synthesis subsystem.

4. The green ammonia synthesis system of claim 1, wherein, According to a real-time rate of hydrogen production of the water electrolysis subsystem, a flow 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.

5. The green ammonia synthesis system of claim 1 or 2, wherein, The light-thermal equipment (1) comprises: A light concentrator adapted to focus radiation of sunlight (50); A solar tower; A heat absorption device arranged on the solar tower; The light-thermal equipment (1) is adapted to focus the radiation of sunlight (50) into the heat absorption device by the light concentrator, and heat the heat storage medium by the heat absorption device.

6. The green ammonia synthesis system of claim 1 or 2, wherein, The second heat storage structure (6) is connected with the third heat storage structure (8) through a first valve (7).

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