Hydrogen storage and ammonia separation integrated system and method

Abstract

The invention relates to a hydrogen storage and ammonia separation integrated system, which belongs to the technical field of ammonia preparation and comprises a hydrogen production device, a nitrogen production device, an ammonia synthesis device, a first liquid ammonia separation device, a circulating compressor, a plurality of high-pressure gas storage tanks and a plurality of liquid-driven gas compressors, the exhaust ends of the hydrogen production device and the nitrogen production device are jointly connected with the gas inlet end of the liquid-driven gas compressor; the liquid-driven gas compressors are in one-to-one correspondence with the high-pressure gas storage tanks, and the exhaust ends of the liquid-driven gas compressors are connected with the fresh gas inlet ends of the high-pressure gas storage tanks; the gas inlet end of the ammonia synthesis device is connected with the gas exhaust ends of all the high-pressure gas storage tanks; the exhaust end of the ammonia synthesis device is connected with the gas inlet end of the first liquid ammonia separation device; the exhaust end of the first liquid ammonia separation device is connected with the gas inlet end of the circulating compressor; and the exhaust end of the circulating compressor is connected with the gas inlet end of the ammonia synthesis device. The device and the method have the effects of adapting to the hydrogen supply fluctuation condition of green electricity hydrogen production and ensuring that the ammonia synthesis device is stable and can continuously operate.

Description

Technical Field

[0001] This application relates to the technical field of ammonia preparation, and particularly to a hydrogen storage and ammonia separation integrated system and method. Background Art

[0002] In the current hydrogen energy industry chain, the production, storage, and application of hydrogen are one of the key links. There are various ways to produce hydrogen, which can be mainly divided into hydrogen production from fossil fuels, electrolytic water hydrogen production, and biomass hydrogen production, etc. Among them, electrolytic water hydrogen production is a relatively concerned clean hydrogen production method at present. Wind power generation, nuclear power, hydropower, and thermal power can all be used for electrolytic water hydrogen production, and wind power generation, as an important way of renewable energy hydrogen production, has the advantage of low-carbon environmental protection.

[0003] In terms of hydrogen storage, the synthesis of ammonia (NH3) from hydrogen is a relatively popular hydrogen storage method, mainly because the storage and transportation of ammonia are more economical and safe than those of hydrogen. When hydrogen is needed, ammonia, as a hydrogen carrier, can be catalytically decomposed to be reconverted into hydrogen.

[0004] Existing hydrogen storage and ammonia separation usually use a syngas compressor to pressurize hydrogen and nitrogen and then transport them into an ammonia production device for synthesizing liquid ammonia. However, the syngas compressor requires a continuous and stable gas flow during use and cannot be started and stopped frequently. When using green electricity (wind power generation) to produce hydrogen, due to the instability of renewable energy, the hydrogen supply fluctuates. If a syngas compressor is used for ammonia synthesis, it will affect the service life of the syngas compressor. And when the hydrogen production decreases or production stops, the syngas compressor must be shut down, which will also cause the ammonia synthesis device to stop. Restarting either the syngas compressor or the ammonia synthesis equipment requires wasting a large amount of energy and time. Summary of the Invention

[0005] In order to adapt to the hydrogen supply fluctuations of green electricity hydrogen production, ensure the stable and sustainable operation of the ammonia synthesis device, reduce the energy consumption caused by equipment start and stop, and improve production efficiency, this application provides a hydrogen storage and ammonia separation integrated system and method.

[0006] The hydrogen storage and ammonia separation integrated system provided by this application adopts the following technical solutions: A hydrogen storage and ammonia separation integrated system includes a hydrogen production device, a nitrogen production device, an ammonia synthesis device, a first liquid ammonia separation device, a recycle compressor, a plurality of high-pressure gas storage tanks, and a plurality of liquid-driven gas compressors; The exhaust ends of the hydrogen production device and the nitrogen production device are jointly connected to the intake end of the liquid-driven gas compressor; The liquid-driven gas compressors correspond to the high-pressure gas storage tanks one by one, and the exhaust end of the liquid-driven gas compressor is connected to the fresh gas intake end of the high-pressure gas storage tank; The intake end of the ammonia synthesis device is connected to the exhaust ends of all the high-pressure gas storage tanks; The exhaust end of the ammonia synthesis device is connected to the intake end of the first liquid ammonia separation device; The exhaust end of the first liquid ammonia separation device is connected to the intake end of the recycle compressor; The exhaust end of the recycle compressor is connected to the intake end of the ammonia synthesis device.

[0007] By adopting the above technical solution, when the hydrogen supply is insufficient, the hydrogen and nitrogen stored in the high-pressure gas storage tank are discharged to the ammonia synthesis device at a stable air pressure, and then the discharged ammonia gas is liquefied, collected and stored through the first liquid ammonia separation device. The recycle compressor pressurizes and refluxes the mixed gas (nitrogen, hydrogen and ammonia) discharged from the ammonia synthesis device to the ammonia synthesis device for continuous ammonia synthesis. When the air pressure in the high-pressure gas storage tank drops to be close to the air pressure at the ammonia synthesis device, another high-pressure gas storage tank is switched to supply gas.

[0008] When the hydrogen supply is sufficient, the liquid-driven gas compressor pressurizes and injects hydrogen and nitrogen into the high-pressure gas storage tank for storage, and at the same time, the gas in the high-pressure gas storage tank can still be continuously supplied to the ammonia synthesis device.

[0009] When the hydrogen production capacity of the hydrogen production device decreases or fluctuates, the high-pressure gas storage tank can be used as a buffer device to supply gas to the ammonia synthesis device at a stable pressure, ensuring the continuity and synthesis efficiency of the synthesis process.

[0010] By means of the high-pressure gas storage tank for storing hydrogen and nitrogen, it is possible to avoid the shutdown of the ammonia synthesis device due to insufficient hydrogen supply.

[0011] Moreover, when the hydrogen supply is sufficient, the liquid-driven gas compressor can quickly resume operation, pressurize and store hydrogen and nitrogen in the high-pressure gas storage tank, and the operation of the liquid-driven gas compressor is not affected by the fluctuation of the hydrogen supply air pressure. When the hydrogen supply is insufficient, the liquid-driven gas compressor can be directly shut down, while the high-pressure gas storage tank continues to supply gas stably, without affecting the operation of the ammonia synthesis device.

[0012] In summary, the present technical solution solves the adverse effects of hydrogen supply fluctuations in green electricity hydrogen production on ammonia synthesis. Through the coordinated operation of the high-pressure gas storage tank and the liquid-driven gas compressor, stable gas supply is achieved, ensuring the stable and sustainable operation of the ammonia synthesis device, reducing the energy consumption caused by equipment start-stop, and improving production efficiency.

[0013] Optionally, the high-pressure gas storage tank is a high-pressure syngas separation tank. The exhaust end of the recycle compressor is also connected to the recycle gas inlet of the high-pressure gas storage tank. A first control valve is arranged at the recycle gas inlet of the high-pressure gas storage tank. An ammonia collection well is arranged in the high-pressure gas storage tank, and the ammonia collection well is used for separating liquid ammonia from the high-pressure gas storage tank.

[0014] By adopting the above technical solutions, the recycle compressor can not only boost the pressure of the tail gas discharged from the ammonia synthesis unit and recycle it to the ammonia synthesis unit to recover the unreacted gas, thereby improving the reaction efficiency, but also boost the pressure of the tail gas discharged from the ammonia synthesis unit and recycle it into the high-pressure gas storage tank, so that the gas pressure in the high-pressure gas storage tank can slowly decrease. At the same time, since the gas pressure in the high-pressure gas storage tank is higher than that at the ammonia synthesis unit, it is also beneficial to liquefy and collect more ammonia gas, realizing the secondary diversion of liquid ammonia. Under the same raw material consumption, more liquid ammonia can be recovered, and the liquid ammonia yield can be increased.

[0015] The decreasing speed of the gas pressure in the high-pressure gas storage tank becomes lower, which is beneficial to extending the service life of each gas storage tank. When there is no hydrogen production for a long time (such as at night without solar energy), it ensures that the high-pressure gas storage tank will not be consumed too quickly and cause the equipment to shut down, further guaranteeing the continuity of the ammonia synthesis process. At the same time, the layout of the high-pressure gas storage tank can be reasonably and appropriately reduced, reducing the occupation of the plant area.

[0016] The first control valve can control whether to supply recycled gas to the high-pressure gas storage tank according to the pressure condition of the high-pressure gas storage tank.

[0017] Optionally, it further includes a second liquid ammonia separation device. The exhaust end of the high-pressure gas storage tank is connected to the intake end of the second liquid ammonia separation device, and the exhaust end of the second liquid ammonia separation device is connected to the intake end of the ammonia synthesis unit; A second control valve is arranged between the high-pressure gas storage tank and the second liquid ammonia separation device, and a third control valve is arranged between the second liquid ammonia separation device and the ammonia synthesis unit.

[0018] By adopting the above technical solutions, the recycle compressor pressurizes and injects the mixed gas into the high-pressure gas storage tank. Although some ammonia gas will liquefy under high pressure, the pressurization will cause the temperature to rise, which will also affect the liquefaction of ammonia gas. Therefore, before the mixed gas discharged from the high-pressure gas storage tank enters the ammonia synthesis unit, it is further cooled and liquefied by the second liquid ammonia separation device. More ammonia gas can be produced under high pressure and low temperature, realizing the tertiary diversion of liquid ammonia and further increasing the liquid ammonia yield.

[0019] The second control valve serves as the switch for discharging gas from the high-pressure gas storage tank, and the third control valve can reduce the pressure of the gas discharged from the high-pressure gas storage tank.

[0020] Optionally, both the first liquid ammonia separation device and the second liquid ammonia separation device include a water cooler and a separator, and the exhaust end of the water cooler is connected to the intake end of the separator; The intake end of the water cooler of the first liquid ammonia separation device is connected to the exhaust end of the ammonia synthesis unit, and the exhaust end of the separator of the first liquid ammonia separation device is connected to the intake end of the recycle compressor; The intake end of the water cooler of the second liquid ammonia separation device is connected to the exhaust end of the high-pressure gas storage tank, and the exhaust end of the separator of the second liquid ammonia separation device is connected to the intake end of the ammonia compound device.

[0021] Optionally, a fourth control valve is connected to the exhaust end of the nitrogen production device, and a first pressure transmitter and a gas dryer are installed at the exhaust end of the hydrogen production device. The first pressure transmitter is used to monitor the air pressure at the exhaust end of the hydrogen production device and output a signal.

[0022] By adopting the above technical solution, the hydrogen production situation is judged according to the situation of the first pressure transmitter, so as to judge whether the liquid-driven gas compressor, the first control valve, the second control valve and the third control valve start and stop, and the fourth control valve is adjusted according to the signal of the first pressure transmitter to ensure the accurate ratio of nitrogen and hydrogen. The gas dryer can remove the moisture in the hydrogen to avoid system corrosion or affecting the catalyst performance.

[0023] Optionally, a second pressure transmitter is arranged between the liquid-driven gas compressor and the high-pressure gas storage tank. The second pressure transmitter is used to monitor the air pressure at the exhaust end of the liquid-driven gas compressor and output a signal; A third pressure transmitter is arranged between the high-pressure gas storage tank and the second liquid ammonia separator. The third pressure transmitter is used to monitor the air pressure in the high-pressure gas storage tank and output a signal; A fourth pressure transmitter is installed at the intake end of the ammonia synthesis device. The fourth pressure transmitter is used to detect the gas pressure discharged into the ammonia synthesis device and output a signal; A fifth pressure transmitter is arranged at the exhaust end of the recycle compressor. The fifth pressure transmitter is used to detect the gas pressure discharged by the recycle compressor and output a signal.

[0024] By adopting the above technical solution, the air pressure at multiple positions is detected and signals are transmitted to control the corresponding control valves to open and close and adjust, realizing dynamic adjustment, improving the intelligent level and ensuring the stable operation of the system.

[0025] The present application also provides a hydrogen storage and ammonia separation method adopting the following technical solution: A hydrogen storage and ammonia separation method, applied to the above hydrogen storage and ammonia separation integrated system, includes the following steps: When the hydrogen supply is sufficient, nitrogen and hydrogen are stored in multiple paths under high pressure in proportion, and at the same time, nitrogen and hydrogen are transported under reduced pressure and ammonia synthesis is carried out; When the hydrogen supply is insufficient, nitrogen and hydrogen in multiple paths are transported under reduced pressure in groups in sequence, and ammonia synthesis is carried out. When the air pressure at the high-pressure storage of a group of nitrogen and hydrogen is reduced to be close to the air pressure for ammonia synthesis, another group of nitrogen and hydrogen is switched for transportation under reduced pressure.

[0026] Optionally, when the hydrogen supply is insufficient, the mixed gas discharged from ammonia synthesis is pressurized and transported in a branched manner to the high-pressure storage of nitrogen and ammonia, and then the mixed ammonia, nitrogen, and ammonia are depressurized and transported for ammonia synthesis; When the hydrogen supply resumes to a sufficient state, the newly produced hydrogen and ammonia are pressurized to the high-pressure storage in proportion, so that the gas pressure in the high-pressure storage returns from the pressure close to ammonia synthesis to the initial storage pressure. During the recovery process of the gas pressure in the high-pressure storage, part of the ammonia in the high-pressure storage liquefies, and the liquid ammonia generated in the high-pressure storage is collected.

[0027] Optionally, during the process of depressurizing and transporting the mixed ammonia, nitrogen, and ammonia, the mixed hydrogen, nitrogen, and ammonia are cooled to liquefy part of the ammonia, and the liquid ammonia generated during the process of depressurizing and cooling transportation is collected.

[0028] Optionally, according to the gas pressure value between the hydrogen production site and the hydraulic pressurization site, it is judged whether the hydrogen supply is sufficient; If the hydrogen supply is sufficient, the newly produced hydrogen and nitrogen are supplied and pressurized to the high-pressure storage in proportion, and according to the gas pressure value between the high-pressure storage and the cooling site, it is judged whether the gas in the high-pressure storage is full; If the hydrogen supply is insufficient, the pressurized storage of hydrogen and nitrogen is stopped, and according to the gas pressure value between the high-pressure storage and the cooling site, it is used as the opening signal for the reflux path between the high-pressure storage and the ammonia synthesis site; When the gas pressure value between the high-pressure storage and the cooling site approaches the gas pressure value between the cooling site and the ammonia synthesis site, another group of ammonia and nitrogen is switched for depressurizing and transporting.

[0029] In summary, the present application includes at least one of the following beneficial technical effects: 1. Solved the adverse effect of hydrogen supply fluctuations in green hydrogen production on ammonia synthesis. Through the coordinated operation of the high-pressure gas storage tank and the liquid-driven gas compressor, stable gas supply is achieved, ensuring the stable and sustainable operation of the ammonia synthesis device, reducing the energy consumption caused by equipment start-stop, and improving production efficiency; 2. The tail gas discharged from the ammonia synthesis device is boosted and circulated into the high-pressure gas storage tank, so that the gas pressure in the high-pressure gas storage tank can slowly decrease, which is beneficial to extending the service life of each gas storage tank. When there is no hydrogen production for a long time (such as no solar energy at night), it is ensured that the high-pressure gas storage tank will not be consumed too quickly and cause equipment shutdown, further ensuring the continuity of the ammonia synthesis process. At the same time, the layout of the high-pressure gas storage tank can be reasonably reduced, reducing the occupation of the factory area space; 3. Boost the tail gas discharged from the ammonia synthesis device and recycle it into the high-pressure gas storage tank. Since the air pressure in the high-pressure gas storage tank is higher than that at the ammonia synthesis device, it is also conducive to liquefying and collecting more ammonia gas, realizing the secondary diversion of liquid ammonia. And before the mixed gas discharged from the high-pressure gas storage tank enters the ammonia synthesis device, it is cooled and liquefied again through the second liquid ammonia separation device. More ammonia gas can be produced under high pressure and low temperature, realizing the tertiary diversion of liquid ammonia. Under the same raw material consumption, more liquid ammonia can be recovered, improving the liquid ammonia production rate; 4. By detecting the air pressure at multiple positions and transmitting signals, control the corresponding control valves to open, close and adjust, realizing dynamic adjustment, improving the intelligent level, and ensuring the stable operation of the system. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application.

[0031] Figure 2 It is a flowchart of the method of an embodiment of the present application.

[0032] Description of the reference numerals: 1, hydrogen production device; 11, first pressure transmitter; 12, gas dryer; 2, nitrogen production device; 21, fourth control valve; 3, liquid-driven gas compressor; 31, second pressure transmitter; 4, high-pressure gas storage tank; 41, first control valve; 5, second liquid ammonia separation device; 51, second control valve; 52, third pressure transmitter; 53, third control valve; 6, ammonia synthesis device; 61, fourth pressure transmitter; 7, first liquid ammonia separation device; 8, recycle compressor; 81, fifth pressure transmitter; 91, water cooler; 92, separator. Detailed Embodiment

[0033] The following is a further detailed description of the present application in conjunction with the attached Figure 1-2 drawings.

[0034] An embodiment of the present application discloses a hydrogen storage and ammonia separation integrated system.

[0035] As Figure 1 , a hydrogen storage and ammonia separation integrated system includes a hydrogen production device 1, a nitrogen production device 2, several liquid-driven gas compressors 3, several high-pressure gas storage tanks 4, several second liquid ammonia separation devices 5, an ammonia synthesis device 6, a first liquid ammonia separation device 7 and a recycle compressor 8.

[0036] The hydrogen production device 1 includes a PEM electrolyzer for producing hydrogen by electrolyzing water and using green electricity for hydrogen production. The nitrogen production device 2 includes PSA nitrogen production. In other embodiments, cryogenic air separation nitrogen production can be used. A first pressure transmitter 11 is installed at the exhaust end of the hydrogen production device 1, and a fourth control valve 21 is installed at the exhaust end of the nitrogen production device 2. After nitrogen passes through the fourth control valve 21 and hydrogen passes through the first pressure transmitter 11, nitrogen and hydrogen merge, and a gas dryer 12 is installed on the merging pipe of nitrogen and hydrogen.

[0037] The merging pipe of nitrogen and hydrogen is connected to a number of liquid-driven gas compressors 3 through a first shunt pipe. The liquid-driven gas compressors 3 correspond to the high-pressure gas storage tanks 4 one by one. Each liquid-driven gas compressor 3 is connected to the fresh gas inlet end of the corresponding high-pressure gas storage tank 4. A second pressure transmitter 31 is installed on the connecting pipeline between the liquid-driven gas compressor 3 and the high-pressure gas storage tank 4.

[0038] The high-pressure gas storage tank 4 is a high-pressure syngas separation tank with a design pressure of 22 MPaG. An ammonia collecting well (not shown in the figure) is provided inside the high-pressure gas storage tank 4, and liquid ammonia can be discharged through the high-pressure gas storage tank 4. The high-pressure gas storage tank 4 corresponds to the second liquid ammonia separation device 5 one by one.

[0039] The second liquid ammonia separation device 5 includes a water cooler 91 and a separator 92. The inlet end of the water cooler 91 of the second liquid ammonia separation device 5 is connected to the exhaust end of the high-pressure gas storage tank 4, and a second control valve 51 is installed on the connecting pipeline between the water cooler 91 of the second liquid ammonia separation device 5 and the high-pressure gas storage tank 4; A third pressure transmitter 52 is installed on the connecting pipeline between the water cooler 91 and the separator 92 of the second liquid ammonia separation device 5; The separators 92 of a number of second liquid ammonia separation devices 5 are connected to the inlet end of the ammonia synthesis device 6 through a second shunt pipe. A third control valve 53 is installed on each branch pipe of the second shunt pipe. The third control valve 53 is a pressure reducing valve, and a fourth pressure transmitter 61 is installed on the main pipe of the second shunt pipe.

[0040] Ammonia synthesis uses a low-pressure ammonia synthesis process with a pressure range of 10 - 15 MPaG. The synthesis tower uses a heat removal reactor and by-produces saturated steam.

[0041] The first liquid ammonia separation device 7 also includes a water cooler 91 and a separator 92. The exhaust end of the ammonia synthesis device 6 is connected to the inlet end of the water cooler 91 of the first liquid ammonia separation device 7. The exhaust end of the water cooler 91 of the first liquid ammonia separation device 7 is connected to the inlet end of the separator 92 of the first liquid ammonia separation device 7. The exhaust end of the separator 92 of the first liquid ammonia separation device 7 is connected to the inlet end of the recycle compressor 8.

[0042] The intake end of the recycle compressor 8 is divided into two paths. One intake end of the recycle compressor 8 is connected to the intake end of the ammonia synthesis unit 6. One intake end of the recycle compressor 8 is connected to a third shunt pipe, and the third shunt pipe is connected to the recycle gas intake ends of all the high-pressure gas storage tanks 4. A first control valve 41 is installed on each branch pipe of the third shunt pipe, and a fifth pressure transmitter 81 is installed on the main pipe of the third shunt pipe.

[0043] The recycle compressor 8 can pressurize and output two gases with different air pressures and transport them to the ammonia synthesis unit 6 and the high-pressure gas storage tank 4 respectively. The recycle compressor 8 can be a parallel turbine recycle machine / two-stage turbine compressor, which is achieved by inter-stage extraction of gas. Or only a first-stage gas compressor can be set, and the air pressure of the gas entering the ammonia synthesis unit 6 is adjusted by a pressure reducing valve.

[0044] The implementation principle of the embodiment of this application is as follows: When the hydrogen supply is insufficient, the hydrogen and nitrogen stored in the high-pressure gas storage tank 4 are discharged to the ammonia synthesis unit 6 at a stable air pressure. Then the discharged ammonia gas is liquefied and collected and stored through the first liquid ammonia separation device 7. The recycle compressor 8 pressurizes the mixed gas (nitrogen, hydrogen and ammonia) discharged from the ammonia synthesis unit 6 and returns it to the ammonia synthesis unit 6 for continuous ammonia synthesis. And the tail gas discharged from the ammonia synthesis unit 6 is boosted and recycled into the high-pressure gas storage tank 4, so that the gas pressure in the high-pressure gas storage tank 4 can slowly drop. Since the air pressure in the high-pressure gas storage tank 4 is higher than the air pressure at the ammonia synthesis unit 6, it is also beneficial to liquefy and collect more ammonia gas, realizing secondary shunt of liquid ammonia. Before the mixed gas discharged from the high-pressure gas storage tank 4 enters the ammonia synthesis unit 6, it is cooled and liquefied again through the second liquid ammonia separation device 5, and more ammonia gas can be produced under high pressure and low temperature, realizing tertiary shunt of liquid ammonia. When the air pressure in the high-pressure gas storage tank 4 drops to be close to the air pressure at the ammonia synthesis unit 6, another high-pressure gas storage tank 4 is switched to supply gas again.

[0045] When the hydrogen supply is sufficient, the liquid-driven gas compressor 3 pressurizes and injects hydrogen and nitrogen into the high-pressure gas storage tank 4 for storage, and at the same time, the gas in the high-pressure gas storage tank 4 can still be continuously supplied to the ammonia synthesis unit 6.

[0046] In summary, this technical solution solves the adverse effect of hydrogen supply fluctuations in green hydrogen production on ammonia synthesis. Through the coordinated operation of the high-pressure gas storage tank 4 and the liquid-driven gas compressor 3, stable gas supply is achieved, ensuring the stable and sustainable operation of the ammonia synthesis unit 6, reducing the energy consumption caused by equipment start-stop, and improving production efficiency; Moreover, when there is no hydrogen production for a long time (for example, there is no solar energy at night), it is ensured that the high-pressure gas storage tank 4 will not be consumed too quickly and cause equipment shutdown, further ensuring the continuity of the ammonia synthesis process. At the same time, the layout of the high-pressure gas storage tank 4 can be reasonably and appropriately reduced, reducing the occupation of the factory area space; Meanwhile, under the same raw material consumption, more liquid ammonia can be recovered, improving the liquid ammonia yield.

[0047] For example Figure 2 , the embodiment of the present application also discloses a hydrogen storage and ammonia separation method, including the following steps: Judge whether the hydrogen supply is sufficient according to the air pressure value between the hydrogen production site and the hydraulic pressurization site: Specifically, according to the value of the first pressure transmitter 11, judge whether the hydrogen supply is sufficient.

[0048] If the hydrogen supply is insufficient, execute step a1; if the hydrogen supply is sufficient, execute step b1.

[0049] a1. Stop the high-pressure storage of nitrogen and hydrogen; Specifically, close the fourth control valve 21 and stop the liquid-driven gas compressor 3.

[0050] a2. Sequentially depressurize and cool multiple paths of nitrogen and hydrogen in groups, and at the same time separate and collect the liquid ammonia; Each group can have only one path of nitrogen and hydrogen for transportation, or two or more paths of nitrogen and hydrogen for transportation simultaneously. In the embodiment of the present application, one path of nitrogen and hydrogen is used for transportation.

[0051] The specific operation of gas depressurization transportation is to open the second control valve 51 to discharge the gas in the high-pressure storage tank, and adjust the third control valve 53 according to the value of the fourth pressure transmitter 61, so that the pressure of the gas discharged from the third control valve 53 drops to be close to and greater than the air pressure of the ammonia synthesis device 6. For example, if the air pressure value of the ammonia synthesis device 6 is 15 MPa, the pressure of the gas discharged from the third control valve 53 can be in the range of 15 - 16 MPa.

[0052] The specific operation of multi-stage separation and collection of liquid ammonia is that the gas in the high-pressure gas storage tank 4 is mixed with a small amount of ammonia for forward production cycle. After the second control valve 51 is opened, the gas in the high-pressure gas storage tank 4 first passes through the water cooler 91 for cooling and is separated from liquid ammonia in the separator 92. The ammonia separation here is three-stage ammonia separation, and only a small amount of liquid ammonia is separated, and then the gas is depressurized and transported.

[0053] a3. Perform ammonia synthesis and collect liquid ammonia; The specific operation steps are that the gas is depressurized and enters the ammonia synthesis device 6 to produce ammonia. The ammonia passes through the water cooler 91 for cooling and then through the separator 92 to separate liquid ammonia. The ammonia separation here is first-stage ammonia separation, and a large amount of liquid ammonia can be separated.

[0054] a4. When the gas pressure at the high-altitude storage site drops to the set value, the mixed gas discharged from ammonia synthesis is divided into paths and pressurized and transported to the high-pressure storage sites of nitrogen and ammonia, and at the same time the liquid ammonia is separated and collected; The specific operation steps for the split discharge of the mixed gas are as follows. The design pressure of the high-pressure gas storage tank 4 is 22.5 MPa. When the design pressure of the high-pressure gas storage tank 4 drops to 20 MPa (this data is for illustration), the first control valve 41 is opened. The mixed gas (ammonia, nitrogen, and hydrogen) discharged after the first-stage ammonia separation is divided into two paths by the recycle compressor 8. One path of the mixed gas is pressurized to be close to and greater than the gas pressure required by the ammonia synthesis unit 6. For example, the gas pressure required by the ammonia synthesis unit 6 is 15 MPa, and this path of the mixed gas is pressurized to between 15 - 16.2 MPa. The other path of the mixed gas is pressurized to be close to and greater than the current gas pressure value of the high-pressure gas storage tank 4. Specifically, the current gas pressure value of the high-pressure gas storage tank 4 is judged by the third pressure transmitter 52, and the supply gas pressure of the recycle compressor 8 is adjusted according to the fifth pressure transmitter 81.

[0055] The operation steps for liquid ammonia separation are as follows. The mixed gas is pressurized and squeezed into the high-pressure gas storage tank 4. Due to the increase in pressure, the ammonia in the mixed gas liquefies and is discharged from the ammonia collecting well in the high-pressure gas storage tank 4. The ammonia separation at this point is the second-stage ammonia separation, and a certain amount of liquid ammonia can be separated.

[0056] a5. Continuously repeat steps a2 - a4 until the gas pressure value between the high-pressure storage location and the cooling location approaches the gas pressure value between the cooling location and the ammonia synthesis location, then switch to another group of ammonia and nitrogen for pressure reduction transportation; The specific operation steps are as follows. Close the first control valve 41 and the second control valve 51 of the current gas storage tank, and open the first control valve 41, the second control valve 51, and the third control valve 53 of other gas storage tanks.

[0057] b1. For the high-pressure storage of nitrogen and hydrogen, stop the split pressure transportation of the mixed gas discharged from ammonia synthesis to the high-pressure storage location of nitrogen and ammonia, and separate and collect the liquid ammonia; The specific operation steps are as follows. Start the liquid-driven gas compressor 3, close the first control valve 41, open the second control valve 51 of the corresponding high-pressure gas storage tank 4, adjust the liquid-driven gas compressor 3 according to the second pressure transmitter 31, and the liquid-driven gas compressor 3 injects gas into the high-pressure gas storage tank 4. The first pressure transmitter 11 is used to judge whether the gas is full. When the gas is injected into the high-pressure gas storage tank 4, the increase in pressure will cause the ammonia in the high-pressure gas storage tank 4 to liquefy and be discharged. The ammonia separation at this point is the second-stage ammonia separation.

[0058] b2. Conduct pressure reduction and temperature reduction transportation for nitrogen and hydrogen, and at the same time separate and collect the liquid ammonia; The specific operation steps are as follows. Inflate one group of high-pressure gas storage tanks 4 without exhausting, and do not inflate another group of gas storage tanks. Open the third control valve 53 to directly exhaust. It is also possible to exhaust while inflating the high-pressure gas storage tank 4, and the specific choice is based on the usage situation of the high-pressure gas storage tank 4. The liquid ammonia collection is the third-stage ammonia separation, which is the same as the above third-stage ammonia separation operation.

[0059] b3. Carry out ammonia synthesis and collect liquid ammonia; b4. Repeat steps b1 - b3. When the air pressure value between the high - pressure storage and the cooling place approaches the air pressure value between the cooling place and the ammonia synthesis place, switch to another group of ammonia and nitrogen for pressure - reducing transportation.

[0060] The above are all preferred embodiments of the present application. It does not limit the protection scope of the present application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A hydrogen storage and ammonia separation integrated system, characterized in that: It includes a hydrogen production device (1), a nitrogen production device (2), an ammonia synthesis device (6), a first liquid ammonia separation device (7), a recycle compressor (8), a number of high-pressure gas storage tanks (4) and a number of liquid-driven gas compressors (3); The exhaust ends of the hydrogen production device (1) and the nitrogen production device (2) are jointly connected to the intake end of the liquid-driven gas compressor (3); The liquid-driven gas compressors (3) correspond one-to-one to the high-pressure gas storage tanks (4), and the exhaust end of the liquid-driven gas compressor (3) is connected to the fresh gas intake end of the high-pressure gas storage tank (4); The intake end of the ammonia synthesis device (6) is connected to the exhaust ends of all the high-pressure gas storage tanks (4); The exhaust end of the ammonia synthesis device (6) is connected to the intake end of the first liquid ammonia separation device (7); The exhaust end of the first liquid ammonia separation device (7) is connected to the intake end of the recycle compressor (8); The exhaust end of the recycle compressor (8) is connected to the intake end of the ammonia synthesis device (6).

2. The integrated hydrogen storage and ammonia separation system according to claim 1, wherein: The high-pressure gas storage tank (4) is a high-pressure synthesis gas separation tank. The exhaust end of the recycle compressor (8) is also connected to the recycle gas inlet of the high-pressure gas storage tank (4). A first control valve (41) is provided at the recycle gas inlet of the high-pressure gas storage tank (4). An ammonia collection well is provided in the high-pressure gas storage tank (4) for separating liquid ammonia from the high-pressure gas storage tank (4).

3. The integrated hydrogen storage and ammonia separation system according to claim 2, characterized in that: It further includes a second liquid ammonia separation device (5). The exhaust end of the high-pressure gas storage tank (4) is connected to the intake end of the second liquid ammonia separation device (5), and the exhaust end of the second liquid ammonia separation device (5) is connected to the intake end of the ammonia synthesis device (6); A second control valve (51) is provided between the high-pressure gas storage tank (4) and the second liquid ammonia separation device (5), and a third control valve (53) is provided between the second liquid ammonia separation device (5) and the ammonia synthesis device (6).

4. The integrated hydrogen storage and ammonia separation system according to claim 3, characterized in that: Both the first liquid ammonia separation device (7) and the second liquid ammonia separation device (5) include a water cooler (91) and a separator (92). The exhaust end of the water cooler (91) is connected to the intake end of the separator (92); The intake end of the water cooler (91) of the first liquid ammonia separation device (7) is connected to the exhaust end of the ammonia synthesis device (6), and the exhaust end of the separator (92) of the first liquid ammonia separation device (7) is connected to the intake end of the recycle compressor (8); The intake end of the water cooler (91) of the second liquid ammonia separation device (5) is connected to the exhaust end of the high-pressure gas storage tank (4), and the exhaust end of the separator (92) of the second liquid ammonia separation device (5) is connected to the intake end of the ammonia synthesis device (6).

5. The integrated hydrogen storage and ammonia separation system according to claim 1, characterized in that: A fourth control valve (21) is connected to the exhaust end of the nitrogen production device (2). A first pressure transmitter (11) and a gas dryer (12) are installed at the exhaust end of the hydrogen production device (1). The first pressure transmitter (11) is used to monitor the air pressure at the exhaust end of the hydrogen production device (1) and output a signal.

6. The integrated hydrogen storage and ammonia separation system according to claim 4, characterized in that: A second pressure transmitter (31) is provided between the liquid-driven gas compressor (3) and the high-pressure gas storage tank (4), and the second pressure transmitter (31) is used to monitor the air pressure at the exhaust end of the liquid-driven gas compressor (3) and output a signal; A third pressure transmitter (52) is provided between the high-pressure gas storage tank (4) and the second liquid ammonia separator (92), and the third pressure transmitter (52) is used to monitor the air pressure in the high-pressure gas storage tank (4) and output a signal; A fourth pressure transmitter (61) is installed at the intake end of the ammonia synthesis device (6), and the fourth pressure transmitter (61) is used to detect the gas pressure of the gas discharged into the ammonia synthesis device (6) and output a signal; A fifth pressure transmitter (81) is provided at the exhaust end of the circulation compressor (8), and the fifth pressure transmitter (81) is used to detect the gas pressure of the gas discharged by the circulation compressor (8) and output a signal.

7. A method for storing hydrogen and separating ammonia, characterized in that: It includes the following steps: When the hydrogen supply is sufficient, nitrogen and hydrogen are stored in multiple paths under high pressure in proportion, and at the same time, nitrogen and hydrogen are transported under reduced pressure and ammonia synthesis is carried out; When the hydrogen supply is insufficient, nitrogen and hydrogen in multiple paths are transported under reduced pressure in groups in sequence, and ammonia synthesis is carried out. When the air pressure at the high-pressure storage of a group of nitrogen and hydrogen decreases during transportation to be close to the air pressure for ammonia synthesis, another group of nitrogen and hydrogen is switched for transportation under reduced pressure.

8. The hydrogen storage and ammonia separation method according to claim 7, characterized in that: When the hydrogen supply is insufficient, the mixed gas discharged from ammonia synthesis is transported under pressure in multiple paths to the high-pressure storage of nitrogen and ammonia, and then the mixed ammonia, nitrogen and ammonia are transported under reduced pressure for ammonia synthesis; When the hydrogen resumes to a sufficient supply state, the newly produced hydrogen and ammonia are pressurized to the high-pressure storage in proportion, so that the air pressure at the high-pressure storage returns from the air pressure close to ammonia synthesis to the initial storage air pressure. And during the recovery process of the air pressure at the high-pressure storage, part of the ammonia in the high-pressure storage liquefies, and the liquid ammonia generated at the high-pressure storage is collected.

9. The hydrogen storage and ammonia separation method according to claim 8, characterized in that: During the process of transporting the mixed ammonia, nitrogen and ammonia under reduced pressure, the mixed hydrogen, nitrogen and ammonia are cooled to liquefy part of the ammonia, and the liquid ammonia generated during the process of transporting under reduced pressure and cooling is collected.

10. The hydrogen storage and ammonia separation method according to claim 9, characterized in that: Judge whether the hydrogen supply is sufficient according to the air pressure value between the hydrogen production place and the hydraulic pressurization place; If the hydrogen supply is sufficient, the newly produced hydrogen and nitrogen are supplied and pressurized to the high-pressure storage in proportion, and it is judged whether the gas in the high-pressure storage is full according to the air pressure value between the high-pressure storage and the cooling place; If the hydrogen supply is insufficient, the pressurized storage of hydrogen and nitrogen is stopped, and according to the air pressure value between the high-pressure storage and the cooling place, it is used as a signal to open the reflux path between the high-pressure storage and the ammonia synthesis place; When the air pressure value between the high-pressure storage and the cooling place approaches the air pressure value between the cooling place and the ammonia synthesis place, another group of ammonia and nitrogen is switched for transportation under reduced pressure.

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