Green ammonia synthesis system and method
By recycling and utilizing air compressed heat and liquid nitrogen vaporization cooling energy in the ammonia synthesis system, the problems of high cost of hydrogen storage and transportation methods and mismatch of production capacity and application distribution are solved, and efficient supply of nitrogen and energy saving and consumption reduction of synthetic ammonia are achieved.
Patent Information
- Application Number
- CN202411774510.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-03-07
AI Technical Summary
The existing hydrogen energy storage and transportation methods are expensive, and the hydrogen production capacity does not match the application distribution, resulting in weak technology in the storage and transportation links.
A ingammonia synthesis system is adopted, including a nitrogen supply system, a renewable energy hydrogen production system and an ammonia synthesis system. By recycling air compression heat and liquid nitrogen vaporization and cooling energy, the system process and thermal engineering scheme are optimized, so as to achieve efficient supply of nitrogen and energy saving and consumption reduction of synthetic ammonia.
It realizes the continuous and stable supply and flexible regulation of nitrogen, reduces energy consumption and carbon emissions during the synthesis of ammonia, and improves the energy-saving and consumption-reduction efficiency of the system.
Smart Images
Figure CN119565501A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of energy and chemical technology, and in particular to a green ammonia synthesis system and method. Background Art
[0002] Hydrogen energy is a secondary energy source with abundant sources, green and low carbon, and wide applications. It is storable, movable, and controllable. It is an ideal carrier of electric energy and an important chemical raw material with a huge scale. At present, the storage and transportation methods of hydrogen energy are single and costly. The storage and transportation link has become a bottleneck that needs to be broken through in the commercial application of hydrogen energy. In addition, the distribution of existing hydrogen production resources in my country is extremely uneven, and the distribution of hydrogen production capacity and hydrogen energy application is extremely mismatched. It is urgent to solve the problem of weak technology and high cost in the storage and transportation link.
[0003] Ammonia is a very important chemical product, which is widely used in various fields such as agriculture and industry. Due to its high energy density, easy liquefaction, and convenient storage and transportation, ammonia can be used as a hydrogen storage carrier to indirectly realize the spatial and temporal configuration of hydrogen energy and meet the flexibility requirements of new energy systems. Using hydrogen produced by electrolysis of water from renewable energy and nitrogen obtained by separation of low-temperature air as raw materials to synthesize ammonia can not only realize the localized and effective consumption of new energy, but also is an important way for the green transformation of the chemical industry. It can significantly reduce carbon emissions in the chemical industry and has huge potential for scale. At the same time, ammonia has the potential to be a transportable renewable energy source, which can replace fossil fuels in most areas in the future and become an important part of renewable energy technology.
[0004] The nitrogen source of the synthetic ammonia system is nitrogen produced by air separation technology. Currently, the most widely used air separation method is cryogenic distillation. This method is mature in technology and easy to realize industrialization and large-scale production, but the air separation uses electric drive to generate cooling capacity, and a large amount of circulating condensed water is required to cool the compressed air, which wastes the compression heat in the separation process. In the process of synthetic ammonia, the raw nitrogen needs to be heated and heated, which consumes a lot of heat energy and wastes a lot of low-temperature cooling energy. How to reasonably and scientifically utilize the air compression heat of the air separation system, the waste heat generated by the ammonia synthesis system, and the low-temperature cooling energy contained in the nitrogen supply system itself, and how to optimize the system process and thermal engineering scheme are of great significance to energy saving and consumption reduction in the synthetic ammonia process, and have considerable economic and social benefits.
[0005] Therefore, there is an urgent need for a clean, low-carbon, flexible and efficient ammonia synthesis system and method. Summary of the invention
[0006] In view of this, the present invention provides a green ammonia synthesis system and method to solve the problems raised in the above background technology.
[0007] In order to achieve the above object, the present invention provides the following technical solutions:
[0008] A green ammonia synthesis system comprises a nitrogen supply system, a renewable energy hydrogen production system and a synthetic ammonia system, wherein the nitrogen supply system comprises an air compressor unit, a heat storage heat exchange mechanism, a cold storage heat exchange mechanism, an oxygen-nitrogen separation device and a liquid nitrogen generation device, wherein the heat storage heat exchange mechanism is provided with a heat storage end 1 at one end and a heat exchange end 1 at the other end, wherein the heat storage end comprises a heat storage end 1, wherein the cold storage heat exchange mechanism is provided with a cold storage end at one end and a heat exchange end 2 at the other end, wherein the oxygen-nitrogen separation device is provided with a separation liquid outlet at one end and a separation gas outlet at the other end, wherein the liquid nitrogen generation device is provided with a generated liquid outlet at one end, wherein the air compressor unit, the heat storage end 1, the heat exchange end 2 and the oxygen-nitrogen separation device inlet are sequentially connected through pipelines, wherein the separation liquid outlet is connected with a liquid oxygen storage mechanism, wherein the separation gas outlet is connected with the liquid nitrogen generation device, wherein the generated liquid outlet is connected with a liquid nitrogen storage mechanism, wherein the liquid nitrogen storage mechanism, the cold storage end and the heat exchange end 1 are sequentially connected through pipelines;
[0009] The renewable energy hydrogen production system is connected to the pipeline between the cold storage end and the heat exchange end 1 through a first three-way valve; the synthetic ammonia system is connected to the pipeline of the heat exchange end 1 away from the cold storage end 1 through a second three-way valve.
[0010] Furthermore, the pipeline between the air compressor unit and the heat storage end one is provided with a filter dryer one, the pipeline between the heat storage end one and the heat exchange end two is provided with a filter dryer two and a valve one in sequence, the pipeline between the heat exchange end two and the oxygen-nitrogen separation equipment is provided with a filter dryer three and a first throttle valve in sequence, the pipeline between the separation gas outlet and the liquid nitrogen generation equipment is provided with a filter purification device and a second throttle valve in sequence, the pipeline between the separation liquid outlet and the liquid oxygen storage mechanism is provided with a valve three, the pipeline between the generated liquid outlet and the liquid nitrogen storage mechanism is provided with a valve two, and the pipeline between the liquid nitrogen storage mechanism and the cold storage end is provided with a valve four and a cryogenic pump in sequence.
[0011] Furthermore, the liquid nitrogen generating equipment is provided with a generated gas outlet at one end away from the generated liquid outlet, and the pipeline between the filter dryer three and the first throttle valve is provided with a branch connected to the generated gas outlet, and a gas booster is provided on the branch.
[0012] Furthermore, the oxygen-nitrogen separation equipment and the liquid nitrogen generation equipment are both equipped with a low-temperature turbine expander or a throttling device for providing cooling supplement when the low-temperature cooling capacity is insufficient.
[0013] Furthermore, the renewable energy hydrogen production system includes an electrolytic water device, which is provided with a hydrogen outlet on one side and an oxygen outlet on the other side. The oxygen outlet is connected to an oxygen storage tank via an oxygen compressor, and the hydrogen outlet is connected to a hydrogen storage tank via a first hydrogen compressor. The end of the hydrogen storage tank away from the first hydrogen compressor is connected to the first three-way valve via a second hydrogen compressor, and the electrolytic water device is electrically connected to a renewable energy power generation device.
[0014] Furthermore, the renewable energy power generation equipment includes a power generation system and a controller, the power generation system is electrically connected to the controller and the water electrolysis equipment, and the controller is used to detect the power generation of the power generation system and control the working state of the water electrolysis equipment according to the power generation.
[0015] Further, the synthetic ammonia system includes an ammonia separation device, an ammonia synthesis device and a regenerator. The synthetic ammonia device is provided with a mixed gas inlet at one end and a synthetic gas outlet at the other end. The regenerator is provided with a heating end at one end and a cooling end at the other end. The second three-way valve, the mixed gas inlet and the heating end are connected in sequence through a pipeline. The heat storage end also includes a second heat storage end. The synthetic gas outlet, the cooling end, the second heat storage end and the ammonia separation device are connected in sequence through a pipeline. The ammonia separation device is provided with an ammonia outlet at one end and an ammonia separation gas outlet at the other end. The ammonia outlet is connected to a liquid ammonia storage tank through a cooling device, and the ammonia separation gas outlet is connected to the second three-way valve.
[0016] Furthermore, a catalyst regeneration unit is provided in the synthetic ammonia device, and the catalyst used in the catalyst regeneration unit is one or more of a molten iron catalyst, a ruthenium-based catalyst, an electronic compound catalyst, a cobalt-based catalyst, a nickel-based catalyst, and a metal nitride catalyst.
[0017] Furthermore, the ammonia separation device is one of a temperature swing adsorption device, a pressure swing adsorption device, and a membrane separation device.
[0018] A green ammonia synthesis method is implemented using any one of the green ammonia synthesis systems described above, comprising the following steps:
[0019] S1: The air compressor unit compresses the raw air at room temperature and pressure into a high-pressure and high-temperature state. After being processed by the filter dryer, it enters the heat storage end of the heat storage heat exchange mechanism for cooling. The heat energy is recovered and stored in the heat storage heat exchange mechanism. At this time, the raw air becomes a normal temperature and high-pressure state.
[0020] S2: Normal temperature and high pressure air is discharged from the heat storage end 1, processed by the filter dryer 2, and then enters the heat storage heat exchange mechanism heat exchange end 2 for cooling after the pressure is adjusted by the valve 1. At this time, the raw air becomes low temperature and high pressure;
[0021] S3: Low-temperature and high-pressure air is discharged from the heat exchange end 2, processed by the filter dryer 3, and enters the oxygen-nitrogen separation device after throttling and pressure regulation by the first throttle valve, and is separated into liquid oxygen and cryogenic nitrogen. The liquid oxygen is stored in the liquid oxygen storage mechanism through the separation liquid outlet through the valve 3, and the cryogenic nitrogen is discharged from the separation gas outlet, processed by the filter purification device, and enters the liquid nitrogen generation device after throttling and pressure regulation by the second throttle valve;
[0022] S4: The liquid nitrogen generated by the liquid nitrogen generating device is discharged from the generated liquid outlet and stored in the liquid nitrogen storage mechanism through valve 2. The uncondensed nitrogen is discharged from the generated gas outlet and, after being pressurized by the gas booster, is returned to the oxygen-nitrogen separation device through a branch line to provide cooling capacity supplement therefor.
[0023] S5: The liquid nitrogen in the liquid nitrogen storage mechanism is discharged under the control of valve 4, and becomes high-pressure liquid nitrogen after being pressurized by the cryogenic pump and enters the cold storage end. The cold storage end recovers the cold energy generated during the vaporization of the high-pressure liquid nitrogen, and heats the high-pressure liquid nitrogen into high-pressure nitrogen gas at room temperature;
[0024] S6: The renewable energy power generation equipment controls the water electrolysis equipment to work, and water molecules generate hydrogen and oxygen in the water electrolysis equipment. The oxygen is compressed by the oxygen compressor and stored in the oxygen storage tank, and the hydrogen is compressed by the first hydrogen compressor and stored in the hydrogen storage tank. The hydrogen in the hydrogen storage tank is compressed again by the second hydrogen compressor and enters the first three-way valve to mix with the high-pressure room temperature nitrogen in S5 and enter the heat exchange end 1;
[0025] S7: The heat energy recovered at the heat storage end 1 is used to heat the mixed hydrogen and high-pressure normal-temperature nitrogen through the heat exchange end 1, and enters the temperature raising end through the second three-way valve, and then enters the synthetic ammonia device through the mixed gas inlet after heating again;
[0026] S8: After the mixed gas in the synthetic ammonia device reacts to generate ammonia under the action of the catalyst, it enters the cooling end from the synthetic gas outlet, enters the heat storage end 2 after cooling, and enters the ammonia separation device after cooling again. The heat energy recovered by the heat storage end 2 is used for the heat exchange end 1;
[0027] S9: The mixed gas is separated in the ammonia separation device, and the separated ammonia flows through the cooling device from the ammonia outlet, and is stored in the liquid ammonia storage tank after cooling. The mixed gas after the ammonia is separated flows from the ammonia separation gas outlet into the second three-way valve and the heat exchange end in S7. The mixed hydrogen and high-pressure and high-temperature nitrogen enter the second three-way valve and then enter the heating end to continue the cycle.
[0028] The beneficial effects of the present invention are:
[0029] The air compression heat in the process of producing liquid nitrogen is recovered and stored in the heat storage heat exchange mechanism, and the cold energy in the vaporization process of high-pressure liquid nitrogen in the process of synthesizing ammonia is stored in the cold storage heat exchange mechanism; at the same time, the stored compression heat is used to heat the nitrogen in the process of synthesizing ammonia, and the stored cold energy is used to reduce the air temperature in the process of producing liquid nitrogen; the air compression heat and the cold energy of liquid nitrogen vaporization are respectively recovered and coupled for utilization, which can not only produce more liquid nitrogen while saving energy and reducing consumption, but also ensure the continuous and stable supply and flexible adjustment of nitrogen in the synthetic ammonia system. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.
[0031] Figure 1 The figure is a schematic diagram of the structure of a green ammonia synthesis system of the present invention.
[0032] Among them, in the figure:
[0033] 1. Air compressor unit; 2. Filter-dryer 1; 3. Heat storage and heat exchange mechanism; 4. Filter-dryer 2; 5. Valve 1; 6. Cold storage and heat exchange mechanism; 7. Filter-dryer 3; 8. First throttle valve; 9. Oxygen-nitrogen separation equipment; 10. Filter purification device; 11. Second throttle valve; 12. Liquid nitrogen generation equipment; 13. Gas booster; 14. Valve 2; 15. Liquid nitrogen storage mechanism; 16. Valve 3; 17. Liquid oxygen storage mechanism; 18. Valve 4; 19. Cryogenic pump; 20. First three-way valve; 21. Renewable energy power generation equipment; 22. Water electrolysis equipment; 23. Oxygen compressor; 24. Oxygen storage tank; 25. First hydrogen compressor; 26. Hydrogen storage tank; 27. Second hydrogen compressor; 28. Second three-way valve; 29. Regenerator; 30. Ammonia synthesis device; 31. Ammonia separation device; 32. Cooling device; 33. Liquid ammonia storage tank. DETAILED DESCRIPTION
[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0036] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.
[0037] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.
[0038] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0039] See attached Figure 1The present invention discloses a green ammonia synthesis system, including a nitrogen supply system, a renewable energy hydrogen production system and a synthetic ammonia system. The nitrogen supply system includes an air compressor unit 1, a heat storage heat exchange mechanism 3, a cold storage heat exchange mechanism 6, an oxygen-nitrogen separation device 9 and a liquid nitrogen generation device 12. The heat storage heat exchange mechanism 3 is provided with a heat storage end at one end and a heat exchange end 1 at the other end. The heat storage end includes a heat storage end 1. The cold storage heat exchange mechanism 6 is provided with a cold storage end at one end and a heat exchange end 2 at the other end. The oxygen-nitrogen separation device 9 is provided with a separation liquid outlet at one end and a separation gas outlet at the other end. The liquid nitrogen generation device 12 is provided with a generated liquid outlet at one end. The air compressor unit 1, the heat storage end 1, the heat exchange end 2 and the inlet of the oxygen-nitrogen separation device 9 are connected in sequence through pipelines. The separation liquid outlet is connected with a liquid oxygen storage mechanism 17. The separation gas outlet is connected with the liquid nitrogen generation device 12. The generated liquid outlet is connected with a liquid nitrogen storage mechanism 15. The liquid nitrogen storage mechanism 15, the cold storage end and the heat exchange end 1 are connected in sequence through pipelines.
[0040] The renewable energy hydrogen production system is connected to the pipeline between the cold storage end and the heat exchange end 1 through the first three-way valve 20; the synthetic ammonia system is connected to the pipeline at the heat exchange end 1 far away from the cold storage end through the second three-way valve 28. The air compression heat in the process of producing liquid nitrogen in the present invention is recovered and stored in the heat storage heat exchange mechanism 3, and the cold energy of the high-pressure liquid nitrogen vaporization process in the synthetic ammonia process is stored in the cold storage heat exchange mechanism 6; at the same time, the stored compression heat is used to heat the nitrogen in the synthetic ammonia process, and the stored cold energy is used to reduce the air temperature in the process of producing liquid nitrogen; the air compression heat and the liquid nitrogen vaporization cold energy are recovered and coupled for use, which can not only produce more liquid nitrogen while saving energy and reducing consumption, but also ensure the continuous and stable supply and flexible adjustment of nitrogen in the synthetic ammonia system.
[0041] The pipeline between the air compressor unit 1 and the heat storage end 1 is provided with a filter dryer 2 for removing carbon dioxide, water vapor and solid impurities in the raw air; the pipeline between the heat storage end 1 and the heat exchange end 2 is provided with a filter dryer 2 4 and a valve 5 in sequence to further remove carbon dioxide and water vapor in the raw air; the pipeline between the heat exchange end 2 and the oxygen-nitrogen separation device 9 is provided with a filter dryer 3 7 and a first throttle valve 8 in sequence, the filter dryer 3 7 further removes carbon dioxide, water vapor and solid impurities in the raw air, and the first throttle valve 8 is used to control the intake pressure of the oxygen-nitrogen separation device 9, thereby controlling the temperature and the liquefaction amount; the separation gas outlet is connected to the liquid nitrogen production line. The pipelines between the generating equipment 12 are provided with a filtering and purifying device 10 and a second throttle valve 11 in sequence. The filtering and purifying device 10 is used to remove liquid oxygen and the like that may be carried in the nitrogen. The second throttle valve 11 is used to control the intake pressure of the liquid nitrogen generating equipment 12, thereby controlling the temperature and the liquefaction amount. The pipeline between the separation liquid outlet and the liquid oxygen storage mechanism 17 is provided with a valve three 16, the pipeline between the generating liquid outlet and the liquid nitrogen storage mechanism 15 is provided with a valve two 14, and the pipeline between the liquid nitrogen storage mechanism 15 and the cold storage end is provided with a valve four 18 and a cryogenic pump 19 in sequence. When providing nitrogen to the synthetic ammonia system, the nitrogen pressure and flow are adjusted by controlling the cryogenic pump 19.
[0042] The liquid nitrogen generating device 12 is provided with a generated gas outlet at one end away from the generated liquid outlet. The pipeline between the filter dryer 3 7 and the first throttle valve 8 is provided with a branch connected to the generated gas outlet. A gas booster 13 is provided on the branch. The low-temperature nitrogen is pressurized and returned to the oxygen-nitrogen separation device 9 to provide cooling supplement.
[0043] The air compressor unit 1 includes one compressor or multiple compressors connected in series or integrated into an integral multi-stage compressor. The compressor inlet is connected to the air source, and the outlet is connected to the filter dryer 2. When there are multiple compressors, the multiple compressors are in a coaxial series form or a split-axis parallel form; in the parallel form, each split-axis is dynamically connected to the main drive shaft; the exhaust gas of each compressor passes through the heat storage and heat exchange mechanism 3, and the compressor adopts piston type, axial flow type, centrifugal type, screw type or mixed type.
[0044] The heat storage and heat exchange mechanism 3 is an insulated container, including a heat storage heat exchanger or a plurality of heat storage heat exchanger groups connected in series or in parallel, and is provided with air pipelines, nitrogen pipelines and heat storage medium, in which air and nitrogen exchange heat with the heat storage medium in a non-direct contact manner. The heat storage medium used by the heat storage and heat exchange mechanism 3 is one or more of water, paraffin, biomass oil, inorganic crystalline hydrated salt, molten salt, metal and its alloy, organic fatty acid, stone, rock and concrete. When producing liquid nitrogen, the heat storage and heat exchange mechanism 3 recovers and stores the compressed heat of air; when providing nitrogen for the synthetic ammonia system, it heats the compressed nitrogen before entering the synthetic ammonia reactor.
[0045] The cold storage heat exchange mechanism 6 is an insulated container, including a cold storage heat exchanger or a plurality of cold storage heat exchanger groups connected in series or in parallel, and is provided with air pipelines, nitrogen pipelines and cold storage medium, in which air and nitrogen are heat exchanged with the cold storage medium in non-direct contact, and the cold storage medium used by the cold storage heat exchange mechanism 6 is one or more of ice, concrete, aluminum strip disc or other metal substances, or one or more of ammonia and its aqueous solution, salt aqueous solution, alkane, olefin substances and their compounds with a solid-liquid phase transition temperature between 81K and 273K. When the synthetic ammonia system provides nitrogen, the cold storage heat exchange mechanism 6 stores the cold energy of liquid and compressed nitrogen; when producing liquid nitrogen, it cools the high-pressure air entering the oxygen-nitrogen separation device 9.
[0046] The oxygen-nitrogen separation device 9 and the liquid nitrogen generation device 12 are both equipped with a low-temperature turbine expander or a throttling device to provide cooling supplement when the low-temperature cooling capacity is insufficient.
[0047] The liquid oxygen storage mechanism 17 is a Dewar tank or a cryogenic storage tank, including one liquid oxygen tank or a combination of multiple parallel liquid oxygen tanks.
[0048] The liquid nitrogen storage mechanism 15 is a Dewar storage tank or a cryogenic storage tank, including one liquid nitrogen storage tank or a combination of multiple parallel liquid nitrogen storage tanks.
[0049] The renewable energy hydrogen production system includes an electrolytic water device 22. A hydrogen outlet is provided on one side of the electrolytic water device 22, and an oxygen outlet is provided on the other side. The oxygen outlet is connected to an oxygen storage tank 24 through an oxygen compressor 23, and the hydrogen outlet is connected to a hydrogen storage tank 26 through a first hydrogen compressor 25. The end of the hydrogen storage tank 26 away from the first hydrogen compressor 25 is connected to a first three-way valve 20 through a second hydrogen compressor 27. The electrolytic water device 22 is electrically connected to a renewable energy power generation device 21.
[0050] The renewable energy power generation equipment 21 includes a power generation system and a controller. The power generation system is electrically connected to the controller and the water electrolysis equipment 22. The controller is used to detect the power generation of the power generation system and control the working state of the water electrolysis equipment 22 according to the power generation.
[0051] The synthetic ammonia system includes an ammonia separation device 31, an ammonia synthesis device 30 and a regenerator 29. The regenerator 29 is a shell and tube heat exchanger or a brazed plate heat exchanger. A mixed gas inlet is provided at one end of the synthetic ammonia device 30, and a synthetic gas outlet is provided at the other end. A heating end is provided at one end of the regenerator 29, and a cooling end is provided at the other end. The second three-way valve 28, the mixed gas inlet and the heating end are connected in sequence through pipelines. The heat storage end also includes a second heat storage end. The synthetic gas outlet, the cooling end, the second heat storage end and the ammonia separation device 31 are connected in sequence through pipelines. An ammonia outlet is provided at one end of the ammonia separation device 31, and an ammonia separation gas outlet is provided at the other end. The ammonia outlet is connected to a liquid ammonia storage tank 33 through a cooling device 32, and the ammonia separation gas outlet is connected to the second three-way valve 28.
[0052] A catalyst regeneration unit is provided in the ammonia synthesis device 30. The catalyst used in the catalyst regeneration unit is one or more of a molten iron catalyst, a ruthenium-based catalyst, an electronic compound catalyst, a cobalt-based catalyst, a nickel-based catalyst, and a metal nitride catalyst.
[0053] The ammonia separation device 31 is one of a temperature swing adsorption device, a pressure swing adsorption device, and a membrane separation device.
[0054] A method for synthesizing green ammonia comprises the following steps:
[0055] S1: The air compressor unit 1 compresses the raw air at normal temperature and pressure to a high-pressure and high-temperature state, and after being processed by the filter dryer 2, it enters the heat storage end of the heat storage heat exchange mechanism 3 for cooling, and the heat energy is recovered and stored in the heat storage heat exchange mechanism 3. At this time, the raw air becomes a normal-temperature and high-pressure state;
[0056] S2: Normal temperature and high pressure air is discharged from the heat storage end 1, processed by the filter dryer 2 4, and then enters the cold storage heat exchange mechanism 6 heat exchange end 2 for cooling after the pressure is adjusted by the valve 1 5. At this time, the raw air becomes low temperature and high pressure state;
[0057] S3: Low-temperature and high-pressure air is discharged from the heat exchange end 2, processed by the filter dryer 3 7, and enters the oxygen-nitrogen separation device 9 after throttling and pressure regulation by the first throttle valve 8, and is separated into liquid oxygen and cryogenic nitrogen. The liquid oxygen is stored in the liquid oxygen storage mechanism 17 through the valve 3 16 from the separation liquid outlet, and the cryogenic nitrogen is discharged from the separation gas outlet, processed by the filter purification device 10, and enters the liquid nitrogen generation device 12 after throttling and pressure regulation by the second throttle valve 11;
[0058] S4: The liquid nitrogen generated by the liquid nitrogen generating device 12 is discharged from the generated liquid outlet and stored in the liquid nitrogen storage mechanism 15 through the valve 2 14. The uncondensed nitrogen is discharged from the generated gas outlet and is pressurized by the gas booster 13 and then returned to the oxygen-nitrogen separation device 9 through a branch line to provide cooling capacity supplement therefor.
[0059] S5: The liquid nitrogen in the liquid nitrogen storage mechanism 15 is discharged under the control of the valve 18, and becomes high-pressure liquid nitrogen after being pressurized by the cryogenic pump 19 and enters the cold storage end. The cold storage end recovers the cold energy generated during the vaporization of the high-pressure liquid nitrogen, and heats the high-pressure liquid nitrogen into high-pressure nitrogen gas at room temperature;
[0060] S6: The renewable energy power generation device 21 controls the water electrolysis device 22 to work, and water molecules generate hydrogen and oxygen in the water electrolysis device 22. The oxygen is compressed by the oxygen compressor 23 and stored in the oxygen storage tank 24. The hydrogen is compressed by the first hydrogen compressor 25 and stored in the hydrogen storage tank 26. The hydrogen in the hydrogen storage tank 26 is compressed again by the second hydrogen compressor 27 and enters the first three-way valve 20 to mix with the high-pressure room-temperature nitrogen in S5 and enter the heat exchange end 1;
[0061] S7: The heat energy recovered at the heat storage end 1 is used to heat the mixed hydrogen and high-pressure normal-temperature nitrogen at the heat exchange end 1, and enters the temperature raising end through the second three-way valve 28, and then enters the synthetic ammonia device 30 through the mixed gas inlet after heating again;
[0062] S8: After the mixed gas in the synthetic ammonia device 30 reacts to generate ammonia under the action of the catalyst, it enters the cooling end through the synthetic gas outlet, enters the heat storage end 2 after cooling, and enters the ammonia separation device 31 after cooling again. The heat energy recovered by the heat storage end 2 is used by the heat exchange end 1;
[0063] S9: The mixed gas is separated in the ammonia separation device 31, and the separated ammonia flows through the cooling device 32 from the ammonia outlet, and is stored in the liquid ammonia storage tank 33 after being cooled. The mixed gas after the ammonia is separated flows into the second three-way valve 28 from the ammonia separation gas outlet and the heat exchange end in S7. The mixed hydrogen and high-pressure and high-temperature nitrogen enter the second three-way valve 28 and then enter the heating end to continue the cycle.
[0064] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A green ammonia synthesis system, characterized in that: The invention comprises a nitrogen supply system, a renewable energy hydrogen production system and a synthetic ammonia system. The nitrogen supply system comprises an air compressor unit (1), a heat storage heat exchange mechanism (3), a cold storage heat exchange mechanism (6), an oxygen-nitrogen separation device (9) and a liquid nitrogen generation device (12). The heat storage heat exchange mechanism (3) is provided with a heat storage end at one end and a heat exchange end 1 at the other end. The heat storage end comprises a heat storage end 1. The cold storage heat exchange mechanism (6) is provided with a cold storage end at one end and a heat exchange end 2 at the other end. The oxygen-nitrogen separation device (9) is provided with a separation liquid outlet at one end and a separation liquid outlet at the other end. A separation gas outlet is provided, one end of the liquid nitrogen generating device (12) is provided with a generated liquid outlet, the air compressor unit (1), the first heat storage end, the second heat exchange end and the inlet of the oxygen-nitrogen separation device (9) are sequentially connected through pipelines, the separation liquid outlet is connected to a liquid oxygen storage mechanism (17), the separation gas outlet is connected to the liquid nitrogen generating device (12), the generated liquid outlet is connected to a liquid nitrogen storage mechanism (15), and the liquid nitrogen storage mechanism (15), the cold storage end and the first heat exchange end are sequentially connected through pipelines; The renewable energy hydrogen production system is connected to the pipeline between the cold storage end and the heat exchange end one through a first three-way valve (20); the synthetic ammonia system is connected to the pipeline at the heat exchange end one far away from the cold storage end one through a second three-way valve (28).
2. A green ammonia synthesis system according to claim 1, characterized in that: The pipeline between the air compressor unit (1) and the heat storage end 1 is provided with a filter dryer 1 (2), the pipeline between the heat storage end 1 and the heat exchange end 2 is provided with a filter dryer 2 (4) and a valve 1 (5) in sequence, the pipeline between the heat exchange end 2 and the oxygen-nitrogen separation device (9) is provided with a filter dryer 3 (7) and a first throttle valve (8) in sequence, the pipeline between the separation gas outlet and the liquid nitrogen generation device (12) is provided with a filter purification device (10) and a second throttle valve (11) in sequence, the pipeline between the separation liquid outlet and the liquid oxygen storage mechanism (17) is provided with a valve 3 (16), the pipeline between the generated liquid outlet and the liquid nitrogen storage mechanism (15) is provided with a valve 2 (14), and the pipeline between the liquid nitrogen storage mechanism (15) and the cold storage end is provided with a valve 4 (18) and a cryogenic pump (19) in sequence.
3. A green ammonia synthesis system according to claim 2, characterized in that: The liquid nitrogen generating device (12) is provided with a generated gas outlet at one end away from the generated liquid outlet, and a branch is provided on the pipeline between the filter dryer (7) and the first throttle valve (8) to communicate with the generated gas outlet, and a gas booster (13) is provided on the branch.
4. A green ammonia synthesis system according to claim 1, characterized in that: The oxygen-nitrogen separation device (9) and the liquid nitrogen generation device (12) are both equipped with a low-temperature turbine expander or a throttling device for providing cooling capacity supplement when the low-temperature cooling capacity is insufficient.
5. A green ammonia synthesis system according to claim 1, characterized in that: The renewable energy hydrogen production system comprises a water electrolysis device (22), wherein one side of the water electrolysis device (22) is provided with a hydrogen outlet, and the other side is provided with an oxygen outlet, wherein the oxygen outlet is connected to an oxygen storage tank (24) via an oxygen compressor (23), and the hydrogen outlet is connected to a hydrogen storage tank (26) via a first hydrogen compressor (25), and an end of the hydrogen storage tank (26) away from the first hydrogen compressor (25) is connected to the first three-way valve (20) via a second hydrogen compressor (27), and the water electrolysis device (22) is electrically connected to a renewable energy power generation device (21).
6. A green ammonia synthesis system according to claim 5, characterized in that: The renewable energy power generation equipment (21) comprises a power generation system and a controller, wherein the power generation system is electrically connected to the controller and the water electrolysis equipment (22), and the controller is used to detect the power generation of the power generation system and control the working state of the water electrolysis equipment (22) according to the power generation.
7. A green ammonia synthesis system according to claim 1, characterized in that: The synthetic ammonia system comprises an ammonia separation device (31), an ammonia synthesis device (30) and a regenerator (29). The synthetic ammonia device (30) is provided with a mixed gas inlet at one end and a synthetic gas outlet at the other end. The regenerator (29) is provided with a heating end at one end and a cooling end at the other end. The second three-way valve (28), the mixed gas inlet and the heating end are connected in sequence through a pipeline. The heat storage end further comprises a second heat storage end. The synthetic gas outlet, the cooling end, the second heat storage end and the ammonia separation device (31) are connected in sequence through a pipeline. The ammonia separation device (31) is provided with an ammonia outlet at one end and an ammonia separation gas outlet at the other end. The ammonia outlet is connected to a liquid ammonia storage tank (33) through a cooling device (32). The ammonia separation gas outlet is connected to the second three-way valve (28).
8. A green ammonia synthesis system according to claim 7, characterized in that: The ammonia synthesis device (30) is provided with a catalyst regeneration unit, and the catalyst used in the catalyst regeneration unit is one or more of a molten iron catalyst, a ruthenium-based catalyst, an electronic compound catalyst, a cobalt-based catalyst, a nickel-based catalyst, and a metal nitride catalyst.
9. A green ammonia synthesis system according to claim 7, characterized in that: The ammonia separation device (31) is one of a temperature swing adsorption device, a pressure swing adsorption device, and a membrane separation device.
10. A method for synthesizing green ammonia, characterized in that: A green ammonia synthesis system according to any one of claims 1 to 9 is used to achieve the above, comprising the following steps: S1: The air compressor unit (1) compresses the raw air at room temperature and pressure to a high pressure and high temperature state, and after being processed by the filter dryer (2), enters the heat storage heat exchange mechanism (3) for cooling at the heat storage end, and the heat energy is recovered and stored in the heat storage heat exchange mechanism (3). At this time, the raw air becomes a state of room temperature and high pressure; S2: Normal temperature and high pressure air is discharged from the heat storage end 1, processed by the filter dryer 2 (4), and then enters the cold storage heat exchange mechanism (6) to cool at the heat exchange end 2 after the pressure is adjusted by the valve 1 (5). At this time, the raw air becomes low temperature and high pressure; S3: Low-temperature and high-pressure air is discharged from the heat exchange end 2, processed by the filter dryer 3 (7), and enters the oxygen-nitrogen separation device (9) after throttling and pressure regulation by the first throttle valve (8), and is separated into liquid oxygen and cryogenic nitrogen. The liquid oxygen is stored in the liquid oxygen storage mechanism (17) through the separation liquid outlet through the valve 3 (16), and the cryogenic nitrogen is discharged from the separation gas outlet, processed by the filter purification device (10), and enters the liquid nitrogen generation device (12) after throttling and pressure regulation by the second throttle valve (11); S4: The liquid nitrogen generated by the liquid nitrogen generating device (12) is discharged from the generated liquid outlet and stored in the liquid nitrogen storage mechanism (15) through the second valve (14). The uncondensed nitrogen is discharged from the generated gas outlet and is pressurized by the gas booster (13) and then returned to the oxygen-nitrogen separation device (9) through a branch line to provide cooling capacity supplement therefor. S5: The liquid nitrogen in the liquid nitrogen storage mechanism (15) is discharged under the control of valve four (18), and becomes high-pressure liquid nitrogen after being pressurized by the cryogenic pump (19) and enters the cold storage end. The cold storage end recovers the cold energy generated during the vaporization process of the high-pressure liquid nitrogen, and heats the high-pressure liquid nitrogen to become high-pressure nitrogen gas at room temperature; S6: The renewable energy power generation device (21) controls the water electrolysis device (22) to work, and water molecules generate hydrogen and oxygen in the water electrolysis device (22). The oxygen is compressed by the oxygen compressor (23) and stored in the oxygen storage tank (24). The hydrogen is compressed by the first hydrogen compressor (25) and stored in the hydrogen storage tank (26). The hydrogen in the hydrogen storage tank (26) is compressed again by the second hydrogen compressor (27) and enters the first three-way valve (20) to mix with the high-pressure room-temperature nitrogen in S5 and enter the heat exchange end 1; S7: The heat energy recovered at the heat storage end 1 is used to heat the mixed hydrogen and high-pressure normal-temperature nitrogen at the heat exchange end 1, and enters the temperature raising end through the second three-way valve (28), and after heating again, enters the synthetic ammonia device (30) through the mixed gas inlet; S8: After the mixed gas in the synthetic ammonia device (30) reacts to generate ammonia under the action of the catalyst, it enters the cooling end through the synthetic gas outlet, enters the heat storage end 2 after cooling, and enters the ammonia separation device (31) after cooling again. The heat energy recovered by the heat storage end 2 is used by the heat exchange end 1; S9: The mixed gas is separated in the ammonia separation device (31), and the separated ammonia flows through the cooling device (32) from the ammonia outlet, and is stored in the liquid ammonia storage tank (33) after being cooled. The mixed gas after the ammonia is separated flows into the second three-way valve (28) from the ammonia separation gas outlet and the mixed hydrogen and high-pressure and high-temperature nitrogen at the heat exchange end of S7 after entering the second three-way valve (28) and then enters the temperature rising end to continue the cycle.