Ammonia decomposition hydrogen production system and hydrogen production method

Abstract

This invention discloses an ammonia decomposition reaction hydrogen production system and method. The system includes an ammonia storage device, a heat exchange device, an ammonia decomposition reaction device, a first compression device, and a first adsorption device. The ammonia storage device is connected to the gas inlet of the ammonia decomposition reaction device through a cold liquid channel on the heat exchange device. The gas outlet of the ammonia decomposition reaction device is connected to the first adsorption device through a gas channel on the heat exchange device and via the first compression device. The first adsorption device includes multiple adsorption columns arranged in parallel. The first compression device is simultaneously connected to the inlets of multiple adsorption columns. A control valve is installed between the adsorption inlet of each adsorption column and the first compression device. The adsorption outlets of the multiple adsorption columns are interconnected. A control valve is installed between the adsorption outlets of two adjacent adsorption columns. The adsorption inlet of each adsorption column is connected to the ammonia decomposition reaction device. This system enables the recycling of the tail gas after desorption from the adsorption columns, reducing the environmental damage caused by ammonia and nitrogen oxides.

Description

Technical Field

[0001] This invention relates to the field of clean energy equipment, specifically to an ammonia decomposition hydrogen production system and method. Background Technology

[0002] Hydrogen is an abundant and clean green energy source with high energy density, high calorific value, abundant reserves, wide availability, and high conversion efficiency. Furthermore, its combustion produces water, resulting in no carbon emissions. However, the transportation and storage of hydrogen are key challenges hindering the widespread application of hydrogen energy technology. Ammonia is a carbon-free hydrogen-rich carrier, and ammonia-based hydrogen storage offers unique advantages such as high energy density, ease of storage and transportation, high safety, a mature industrial base, and zero carbon emissions at the end-use stage. Using ammonia as a hydrogen storage carrier, hydrogen can be produced on-site at the energy terminal through ammonia decomposition reactions, directly producing a hydrogen-nitrogen mixture or high-purity hydrogen. Ammonia decomposition for hydrogen production is a crucial reaction process in the "ammonia-hydrogen" energy technology route. In this process, ammonia undergoes thermocatalytic decomposition to generate hydrogen and nitrogen in a volume ratio of 3:1. Due to thermodynamic equilibrium limitations, a small amount of undecomposed ammonia remains in the hydrogen-nitrogen mixture after ammonia decomposition. This low concentration of ammonia typically needs to be removed to the ppm level or even lower through adsorption before it can be used for downstream applications. However, with long-term use, the adsorbent will reach saturation and can no longer adsorb ammonia, requiring periodic desorption and regeneration. In existing technologies, more than two adsorption columns are typically required to perform an alternating "adsorption-desorption" cycle to ensure a long-term gas supply for the ammonia decomposition hydrogen production system. However, during the desorption process in existing processes, not only is additional N2 required to purge the adsorption columns, increasing the system's raw material costs, but the adsorbed ammonia is also inevitably released. Without treatment, this ammonia will be directly emitted into the atmosphere or converted into high concentrations of nitrogen oxides (NOx) through combustion. x NH3 and NO are emitted into the atmosphere. x Both are pollutants in the atmosphere that need to be controlled. In order to truly achieve clean and efficient "ammonia-hydrogen" conversion and utilization, it is necessary to effectively control the emission of ammonia or nitrogen oxides generated during the continuous operation of the system.

[0003] Chinese patent CN208308426U discloses an ammonia decomposition hydrogen production device, including a base plate, a housing, a first adsorption tower, and a second adsorption tower. The housing is located above the base plate, and a heat insulation plate is installed inside the housing. A heat exchanger is installed above the heat insulation plate, and a valve is installed between the heat exchanger and the housing. One end of the heat exchanger passes through the housing and is equipped with a valve, while the other end of the heat exchanger passes through a partition and connects to the interior of a decomposition furnace. A gas pipe is installed at the lower end of the decomposition furnace, and the gas pipe passes through the housing and connects to the first and second adsorption towers. Molecular sieves are installed inside the first and second adsorption towers. The adsorption tower and the second adsorption tower are connected by a valve. This patent converts liquid ammonia into ammonia gas through a heat exchanger, and then converts the ammonia gas into nitrogen and hydrogen gas through a decomposition furnace to reduce the environmental damage caused by ammonia gas. After the decomposition is completed, the hydrogen and nitrogen gas is introduced into the adsorption tower for adsorption to improve the purity of the hydrogen and nitrogen gas. The ammonia decomposition hydrogen production device of this patent requires additional nitrogen gas to purge the adsorption tower, and the saturated adsorption tower needs to be unloaded during the purging process. The system has high raw material costs and poor adsorption efficiency. In addition, there is a risk of ammonia gas leakage and environmental damage during the adsorption process. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes an ammonia decomposition hydrogen production system and method. This system does not release ammonia or nitrogen oxides during adsorption, is suitable for long-term ammonia decomposition gas supply, has low raw material costs, high energy utilization rate, and low energy consumption.

[0005] The present invention adopts the following technical solution:

[0006] A hydrogen production system based on ammonia decomposition reaction includes an ammonia storage device, a heat exchange device, a first compression device of the ammonia decomposition reaction device, and a first adsorption device. The outlet of the ammonia storage device is connected to the gas inlet of the ammonia decomposition reaction device through a cold liquid channel on the heat exchange device, and the gas outlet of the ammonia decomposition reaction device is connected to the first compression device through a gas channel on the heat exchange device. Liquid ammonia discharged from the ammonia storage device and mixed gas discharged from the ammonia decomposition reaction device exchange heat through the heat exchange device, and the gas after heat exchange is introduced into the first compression device.

[0007] The first adsorption device includes multiple adsorption columns arranged in parallel. The outlet of the first compression device is simultaneously connected to the adsorption inlets of the multiple adsorption columns arranged in parallel. A control valve is correspondingly provided on the pipeline between the adsorption inlet of each adsorption column and the first compression device. The adsorption outlets of the multiple adsorption columns are connected to each other. A control valve is provided between the adsorption outlets of two adjacent adsorption columns. The adsorption inlet of each adsorption column is also connected to the gas inlet of the ammonia decomposition reaction device through a pipeline. A control valve is provided on the pipeline between the adsorption inlet of each adsorption column and the ammonia decomposition reaction device. When the control valve located between the adsorption outlets of two adjacent adsorption columns is opened, the mixed gas after adsorption by the adsorption column can be introduced into the ammonia decomposition reaction device through the adsorption inlet of one of the adsorption columns.

[0008] Preferably, the heat exchange device includes a first heat exchanger and a second heat exchanger. The first heat exchanger is provided with a first cold liquid inlet, a first cold liquid outlet, a first hot gas inlet, and a first hot gas outlet. The first cold liquid inlet and the first cold liquid outlet are connected as a pair, and the first hot gas inlet and the first hot gas outlet are also connected as a pair. The second heat exchanger is provided with a second cold gas inlet, a second cold gas outlet, a second hot gas inlet, and a second hot gas outlet. The second cold gas inlet and the second cold gas outlet are also connected as a pair, and the second hot gas inlet and the second hot gas outlet are also connected as a pair. The outlet of the ammonia storage device is connected to the ammonia storage device via the first cold liquid inlet, the first cold liquid outlet, the second cold gas inlet, and the second cold gas outlet in sequence. The gas inlet of the decomposition reaction device is connected, and the gas outlet of the ammonia decomposition reaction device is connected to the inlet of the first compression device in sequence through a second hot gas inlet, a second hot gas outlet, a first hot gas inlet, and a first hot gas outlet; the first heat exchanger can exchange heat between the gas discharged from the second heat exchanger and the gas discharged from the ammonia storage device, and discharge the gas after heat exchange from the first heat exchanger; the second heat exchanger can introduce the gas discharged from the first heat exchanger into the ammonia decomposition reaction device, exchange heat between the gas discharged from the first heat exchanger and the gas discharged from the ammonia decomposition reaction device, and guide the gas after heat exchange back into the first heat exchanger.

[0009] A second compression device is also provided on the pipeline between the gas inlet of the first adsorption device and the ammonia decomposition reaction device.

[0010] A regulating valve is installed on the pipeline between the first cold liquid outlet and the second cold air inlet; an air-cooling device is also installed on the pipeline between the second hot air outlet and the first hot air inlet.

[0011] Buffer tanks are provided at the inlet and outlet ends of the first compression device and at the inlet and outlet ends of the second compression device.

[0012] Preferably, the first adsorption device includes a first adsorption column and a second adsorption column arranged in parallel, and a first control valve, a second control valve, a third control valve, a fourth control valve, a fifth control valve, a sixth control valve, and a seventh control valve disposed at the adsorption inlet and adsorption outlet of the first adsorption device. The first adsorption column has a first adsorption inlet and a first adsorption outlet, and the second adsorption column has a second adsorption inlet and a second adsorption outlet. A first pipe is disposed between the first adsorption inlet and the second adsorption inlet, and the first adsorption outlet and the second adsorption outlet are connected through a second pipe. A third pipe is connected in parallel below the first pipe, a fourth pipe is disposed at the first adsorption outlet, and a fifth pipe is disposed at the second adsorption outlet. The first compression device and the first adsorption inlet are connected by the first control valve, the first compression device and the second adsorption inlet are connected by the third control valve, the second pipe is disposed by the fifth control valve, the fourth pipe is disposed by the second control valve, the fifth pipe is disposed by the fourth control valve, the first adsorption inlet and the ammonia decomposition reaction device are connected by the sixth control valve, and the second adsorption inlet and the ammonia decomposition reaction device are connected by the seventh control valve.

[0013] The system also includes a buffer device and a second adsorption device. The second adsorption device includes multiple adsorption columns arranged in parallel. The adsorption outlet of the adsorption column of the first adsorption device is connected to one end of the buffer device, and the other end of the buffer device is connected to the adsorption inlet of the adsorption column of the second adsorption device.

[0014] Preferably, the second adsorption device includes a third adsorption column and a fourth adsorption column arranged in parallel, and an eighth, ninth, tenth, eleventh, twelfth, thirteenth, and fourteenth control valves disposed at the adsorption inlet and adsorption outlet of the second adsorption device. The third adsorption column is provided with a third adsorption inlet and a third adsorption outlet, and the fourth adsorption column is provided with a fourth adsorption inlet and a fourth adsorption outlet. A sixth pipe is provided between the third adsorption inlet and the fourth adsorption inlet, and the third adsorption outlet and the fourth adsorption outlet are connected through a seventh pipe. An eighth pipe is connected in parallel below the sixth pipe, and a ninth pipe is connected to the third adsorption outlet, and a tenth pipe is connected to the fourth adsorption outlet. A thirteenth control valve is disposed near the third adsorption column on the sixth pipe, and a fourteenth control valve is disposed near the fourth adsorption column on the sixth pipe. An eighth control valve is disposed between the buffer device and the third adsorption inlet, and a tenth control valve is disposed between the buffer device and the fourth adsorption inlet. A twelfth control valve is disposed on the seventh pipe, a ninth control valve is disposed on the ninth pipe, and an eleventh control valve is disposed on the tenth pipe.

[0015] The system also includes a combustion device, wherein the third adsorption inlet of the third adsorption column and the fourth adsorption inlet of the fourth adsorption column are respectively connected to the inlet of the combustion device, and the outlet of the combustion device is connected to the ammonia decomposition reaction device.

[0016] The system also includes a hydrogen fuel cell, the adsorption outlet of the first adsorption device is connected to the hydrogen fuel cell, the outlet of the hydrogen fuel cell is connected to the inlet of the combustion device, and the outlet of the combustion device is connected to the ammonia decomposition reaction device.

[0017] A method for producing hydrogen using an ammonia decomposition reaction hydrogen production system includes the following steps:

[0018] S1. Introduce liquid ammonia into the heat exchanger and heat the liquid ammonia to above 550°C;

[0019] S2. Ammonia gas is introduced into the ammonia decomposition reaction device to carry out the ammonia decomposition reaction;

[0020] S3. Discharge the decomposed mixed gas from the ammonia decomposition reactor and cool it to room temperature;

[0021] S4. The cooled mixed gas is introduced into the first compression device for compression;

[0022] S5. The mixed gas compressed by the first compression device is introduced into the first adsorption column of the first adsorption device, so that the first adsorption column adsorbs the mixed gas until the first adsorption column reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the first adsorption column is passed to the second adsorption column to purge the second adsorption column.

[0023] S6. After the purging is completed, the mixed gas is discharged from the second adsorption column and re-introduced into the ammonia decomposition reaction device to carry out the ammonia decomposition reaction.

[0024] S7. The mixed gas compressed by the first compression device is introduced into the second adsorption column of the adsorption device, so that the second adsorption column adsorbs the mixed gas until the second adsorption column reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the second adsorption column is passed to the first adsorption column to purge the first adsorption column.

[0025] S8. After the purging is completed, the mixed gas is discharged from the first adsorption column and then reintroduced into the ammonia decomposition reaction device to carry out the ammonia decomposition reaction.

[0026] Steps S9, S5-S8 are repeated in a loop.

[0027] The technical solution of this invention has the following advantages:

[0028] A. This invention, by setting up multiple heat exchangers and using valves to control the adsorption columns in the adsorption device, enables simultaneous adsorption and desorption of the adsorption columns. Furthermore, the parallel arrangement of multiple adsorption columns improves the adsorption efficiency of the system. The purge gas from the adsorption columns is compressed by the compressor and then returned to the inlet of the ammonia decomposition reactor. It then merges with the preheated ammonia gas and enters the ammonia decomposition reactor, realizing the ammonia recirculation of the desorption outlet gas and achieving 100% utilization of ammonia.

[0029] B. The entire system of this invention only provides a hydrogen-nitrogen mixture (75% H2 + 25% N2) after deep adsorption and removal of ammonia, with no other exhaust emissions. This reduces the risk of environmental damage from ammonia and nitrogen oxides, achieves zero emissions for the entire system, and improves the purity of hydrogen in the mixed gas. After the ammonia decomposition reaction device decomposes the ammonia, it is connected to the adsorption device for adsorption. After adsorption is completed, a portion of the mixed gas is used to purge the adsorption column that has become saturated. This eliminates the need to introduce an additional gas source as a purging gas, reduces the raw material cost and energy consumption of the system, improves the system's compactness, and also reduces environmental pollution during the production process. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall structure of the hydrogen production system for ammonia decomposition reaction of the present invention (I).

[0032] Figure 2 This is a schematic diagram (II) of the overall structure of the ammonia decomposition reaction hydrogen production system of the present invention.

[0033] Figure 3 This is a schematic diagram (III) of the overall structure of the hydrogen production system for ammonia decomposition reaction of the present invention.

[0034] Figure 4 This is a schematic diagram (IV) of the overall structure of the hydrogen production system for ammonia decomposition reaction of the present invention.

[0035] Figure 5 This is a schematic diagram (V) of the overall structure of the hydrogen production system for ammonia decomposition reaction of the present invention.

[0036] The diagram is labeled as follows:

[0037] 1-Ammonia storage device; 11-Stop valve; 12-Liquid pump;

[0038] 2-Heat exchange device, 21-First heat exchanger, 211-First cold liquid inlet, 212-First cold liquid outlet, 213-First hot gas inlet, 214-First hot gas outlet, 22-Second heat exchanger, 221-Second cold gas inlet, 222-Second cold gas outlet, 223-Second hot gas inlet, 224-Second hot gas outlet, 23-Regulating valve, 24-Air-cooled device;

[0039] 3-Ammonia decomposition reaction apparatus, 31-Gas inlet, 32-Gas outlet;

[0040] 4-First compression device;

[0041] 5-First adsorption device, 51-First adsorption column, 511-First adsorption inlet, 512-First adsorption outlet, 52-Second adsorption column, 521-Second adsorption inlet, 522-Second adsorption outlet, 53-First pipe, 54-Second pipe, 55-Third pipe, 56-Fourth pipe, 57-Fifth pipe;

[0042] 6-Second compression device;

[0043] 7-Buffer device;

[0044] 8-Second adsorption device, 81-Third adsorption column, 811-Third adsorption inlet, 812-Third adsorption outlet, 82-Fourth adsorption column, 821-Fourth adsorption inlet, 822-Fourth adsorption outlet, 83-Sixth pipe, 84-Seventh pipe, 85-Eighth pipe, 86-Ninth pipe, 87-Tenth pipe;

[0045] 9- Combustion device;

[0046] 10- Hydrogen fuel cell;

[0047] 20 - Connecting device;

[0048] a - First control valve, b - Second control valve, c - Third control valve, d - Fourth control valve, e - Fifth control valve, f - Sixth control valve, g - Seventh control valve, h - Eighth control valve, i - Ninth control valve, j - Tenth control valve, k - Eleventh control valve, m - Twelfth control valve, n - Thirteenth control valve, p - Fourteenth control valve. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] like Figure 1As shown, the present invention provides an ammonia decomposition hydrogen production system, including an ammonia storage device 1, a heat exchange device 2, an ammonia decomposition reaction device 3, a first compression device 4, and a first adsorption device 5. The ammonia decomposition reaction device 3 is filled with an ammonia decomposition catalyst. The liquid outlet of the ammonia storage device 1 is connected to the gas inlet 31 of the ammonia decomposition reaction device 3 through a cold liquid channel on the heat exchange device 2. The gas outlet 32 ​​of the ammonia decomposition reaction device 3 is connected to the first compression device 4 through a gas channel on the heat exchange device 2. The liquid ammonia discharged from the ammonia storage device 1 and the mixed gas discharged from the ammonia decomposition reaction device 3 exchange heat through the heat exchange device 2, and the gas after heat exchange is introduced into the first compression device 4. The first adsorption device 5 includes multiple adsorption columns arranged in parallel. The outlet of the first compression device 4 is simultaneously connected to the adsorption inlets of the multiple adsorption columns arranged in parallel. A control valve is correspondingly provided on the pipeline between the adsorption inlet of each adsorption column and the first compression device 4. The adsorption outlets of the multiple adsorption columns are connected to each other. A control valve is provided between the adsorption outlets of two adjacent adsorption columns. The adsorption inlet of each adsorption column is also connected to the gas inlet 31 of the ammonia decomposition reaction device 3 through a pipeline. A control valve is provided on the pipeline between the adsorption inlet of each adsorption column and the ammonia decomposition reaction device 3. When the control valve located between the adsorption outlets of two adjacent adsorption columns is opened, the mixed gas after adsorption by the adsorption column can be introduced into the ammonia decomposition reaction device 3 through the adsorption inlet of one of the adsorption columns for further ammonia decomposition reaction.

[0051] This application's ammonia decomposition hydrogen production system enables simultaneous adsorption and desorption on the adsorption columns, and employs a parallel arrangement of multiple adsorption columns to improve system adsorption efficiency. The purge gas from the adsorption columns is compressed and then returned to the inlet of the ammonia decomposition reactor, where it merges with preheated ammonia gas before entering the reactor, achieving ammonia recirculation in the desorption outlet gas and 100% ammonia utilization. This reduces system energy loss and improves energy utilization. The entire system only provides a hydrogen-nitrogen mixture (75% H2 + 25% N2) after deep adsorption and ammonia removal, with no other tail gas emissions, achieving zero emissions and improving the purity of hydrogen in the mixed gas. The ammonia decomposition hydrogen production system provided by this invention eliminates the need for an additional gas source as purge gas by using partially adsorbed gas for purging, reducing raw material costs and improving system production efficiency.

[0052] Furthermore, the heat exchange device 2 includes a first heat exchanger 21 and a second heat exchanger 22. The first heat exchanger 21 is provided with a first cold liquid inlet 211, a first cold liquid outlet 212, a first hot gas inlet 213 and a first hot gas outlet 214. The first cold liquid inlet 211 and the first cold liquid outlet 212 are connected as a pair, and the first hot gas inlet 213 and the first hot gas outlet 214 are connected as a pair. The second heat exchanger 22 is provided with a second cold gas inlet 221, a second cold gas outlet 222, a second hot gas inlet 223 and a second hot gas outlet 224. The second cold gas inlet 221 and the second cold gas outlet 222 are connected as a pair, and the second hot gas inlet 223 and the second hot gas outlet 224 are connected as a pair. The outlet of the ammonia storage device 1 is connected to the gas inlet 31 of the ammonia decomposition reaction device 3 in sequence through the first cold liquid inlet 211, the first cold liquid outlet 212, the second cold gas inlet 221, and the second cold gas outlet 222. The gas outlet 32 ​​of the ammonia decomposition reaction device 3 is connected to the inlet of the first compression device 4 in sequence through the second hot gas inlet 223, the second hot gas outlet 224, the first hot gas inlet 213, and the first hot gas outlet 214. Specifically, the first cold liquid inlet 211 and the first cold liquid outlet 212 are used to transfer liquid ammonia flowing out of the ammonia storage device 1, and the first hot gas inlet 213 and the first hot gas outlet 214 are used to transfer the mixed gas discharged from the ammonia decomposition reaction device 3 after being cooled by the second heat exchanger 22. The first heat exchanger 21 can heat the liquid ammonia between the first cold liquid inlet 211 and the first cold liquid outlet 212 to vaporize it into ammonia gas. The heat exchange element of the first heat exchanger 21 can transfer the heat of the mixed gas between the first hot gas inlet 213 and the first hot gas outlet 214 to the liquid ammonia flowing between the first cold liquid inlet 211 and the first cold liquid outlet 212, thereby increasing the temperature of the liquid ammonia to accelerate the vaporization of the liquid ammonia into ammonia gas, thereby reducing the heat required for subsequent heating of liquid ammonia, reducing heat consumption, and also effectively utilizing the heat generated by the system. To further control the amount of ammonia flowing into the second heat exchanger 22, so that the ammonia can be fully decomposed to generate enough hydrogen, a regulating valve 23 is provided between the first heat exchanger 21 and the second heat exchanger 22. The regulating valve 23 is used to adjust the gas flow rate of ammonia generated by the vaporization of liquid ammonia into the second heat exchanger 22, thereby controlling the flow rate inside the subsequent ammonia decomposition reaction device 3, so that the heat in the second heat exchanger 22 can be fully converted.The second cold gas inlet 221 and the second cold gas outlet 222 are used to transfer ammonia gas flowing out of the ammonia storage device 1 and vaporized by the first heat exchanger 21; the second hot gas inlet 223 and the second hot gas outlet 224 are used to transfer the mixed gas discharged from the ammonia decomposition reaction device 3. The heat exchange element of the second heat exchanger 22 can further heat the gas heated by the first heat exchanger 21 between the second cold gas inlet 221 and the second cold gas outlet 222 to reach the temperature required for ammonia decomposition. The heat exchange element of the second heat exchanger 22 can convert the heat of the mixed gas between the second hot gas inlet 223 and the second hot gas outlet 224 to the heat of the ammonia gas flowing between the second cold gas inlet 221 and the second cold gas outlet 222, reducing the energy required to heat the ammonia gas to the ammonia decomposition reaction temperature and achieving the effect of saving energy loss; at the same time, it effectively utilizes the heat of the gas after ammonia decomposition and improves the system utilization rate.

[0053] To better control the inflow of liquid ammonia and enable the system to adjust the supply of liquid ammonia according to actual production conditions to obtain a suitable and sufficient amount of hydrogen, the outlet of the ammonia storage device 1 is connected to a shut-off valve 11, which is then connected to a liquid pump 12. Preferably, the liquid pump 12 is externally connected to a pressure transmitter. Through the pressure transmitter, the liquid pump 12 can adjust the inflow of liquid ammonia according to the pressure of the gas in the system, thereby ensuring that the hydrogen generated by the system reaction is within a stable range. This improves both system stability and flexibility, ensuring a sufficient supply of ammonia to the ammonia decomposition system. One end of the liquid pump 12 is connected to the first cold liquid inlet 211 of the first heat exchanger 21 via a pipeline.

[0054] A second compression device 6 is also installed on the pipeline between the gas inlet of the first adsorption device 5 and the ammonia decomposition reaction device 3. The ammonia decomposition reaction device 3 is provided with a gas inlet 31 and a gas outlet 32, which are located at opposite ends of the reaction body of the ammonia decomposition reaction device 3. A connecting device 20 is provided near the gas inlet 31 of the ammonia decomposition reaction device 3. One side of the connecting device 20 is connected to the reaction body of the ammonia decomposition reaction device 3, and the other side is connected to the second cold gas outlet 222 of the second heat exchanger 22. The ammonia gas that has reached the ammonia decomposition temperature discharged from the second heat exchanger 22 and the mixed gas discharged from the second compression device 6 can enter the ammonia decomposition reaction device 3 simultaneously through the connecting device 20 to react and decompose the ammonia gas into hydrogen and nitrogen. The gas outlet 32 ​​of the ammonia decomposition reaction device 3 is connected to the second hot gas inlet 223 of the second heat exchanger 22. The decomposed hydrogen and nitrogen mixed gas is then discharged into the second heat exchanger 22 to heat the ammonia gas introduced from the first heat exchanger 21.

[0055] After being heated by the second heat exchanger 22, the ammonia gas flows into the ammonia decomposition reaction device 3 through the connecting device 20. After undergoing the ammonia decomposition reaction, a mixed gas containing hydrogen, nitrogen and residual ammonia is generated. The mixed gas is then reintroduced into the second hot gas inlet 223 of the second heat exchanger 22 through the gas outlet of the ammonia decomposition reaction device 3. Subsequently, the heat of the mixed gas is transferred to the ammonia gas through the second heat exchange element inside the second heat exchanger 22, so as to reduce the temperature of the mixed gas and increase the temperature of the ammonia gas at the same time, thereby reducing energy loss. Since the gas produced after ammonia decomposition has a high temperature, in order to further reduce the temperature of the mixed gas and make it suitable for the adsorption of the subsequent adsorption device and the purging of the adsorption column, thereby improving the adsorption and purging effects of the adsorption device, an air-cooling device 24 is connected between the second hot gas outlet 224 of the second heat exchanger 22 and the first hot gas inlet 213 of the first heat exchanger 21. The air-cooling device 24 is used to further reduce the temperature of the mixed gas discharged from the second heat exchanger 22, so that the mixed gas can be better applied to the adsorption and purging of the subsequent adsorption device. At the same time, it also reduces the energy required for the first heat exchanger 22 to convert heat, improving the purging and adsorption effects while reducing the overall energy consumption of the system. After being cooled by the air-cooling device 24, the cooled mixed gas is then introduced into the first hot gas inlet 213 of the first heat exchanger 21, and then flows through the first heat exchange element in the first heat exchanger 21. The first heat exchange element transfers the remaining heat of the cooled mixed gas to the liquid ammonia to reduce the temperature of the mixed gas. The cooled mixed gas is then introduced into the first compression device 4 through the first hot gas outlet 214. The first compression device 4 can compress the cooled mixed gas for subsequent adsorption and purging by the first adsorption device 5. Preferably, buffer tanks are provided at both the inlet and outlet ends of the first compression device 4 to improve the compression effect of the first compression device 4 on the gas.

[0056] By setting up a first heat exchanger 21 and a second heat exchanger 22 connected in series, a regulating valve 23 for adjusting the flow rate, and an air-cooling device 24 for cooling the mixed gas, the temperature of the liquid ammonia discharged from the ammonia storage device 1 can be increased, allowing the liquid ammonia to heat up more quickly to reach the temperature required for the subsequent ammonia decomposition reaction, thus improving the efficiency of the ammonia decomposition reaction. At the same time, the first heat exchanger 21 and the second heat exchanger 22 transfer the heat of the gas discharged from the ammonia decomposition reaction device 3 to the ammonia, reducing system heat loss and improving the system's energy utilization rate. Furthermore, the mixed gas after the ammonia decomposition reaction can reach a stable temperature after heat exchange through the first heat exchanger 21 and the second heat exchanger 22, which is also beneficial for the subsequent adsorption of ammonia in the mixed gas by the first adsorption device 5, thereby improving the purity of hydrogen in the mixed gas.

[0057] The first adsorption device 5 includes a first adsorption column 51 and a second adsorption column 52 arranged in parallel, and a first control valve a, a second control valve b, a third control valve c, a fourth control valve d, a fifth control valve e, a sixth control valve f, and a seventh control valve g arranged at the adsorption inlet and adsorption outlet of the first adsorption device 5. The first adsorption column 51 is provided with a first adsorption inlet 511 and a first adsorption outlet 512, and the second adsorption column 52 is provided with a second adsorption inlet 521 and a second adsorption outlet 522. A first pipe 53 is arranged between the first adsorption inlet 511 and the second adsorption inlet 521. The first adsorption outlet 512 and the second adsorption outlet 522 are connected through a second pipe 54. A third pipe 55 is connected in parallel below the first pipe 53. A fourth pipe 56 is arranged on the first adsorption outlet 512, and a fifth pipe 57 is arranged on the second adsorption outlet 522. The fourth pipe 56 is used to discharge the gas adsorbed by the first adsorption column 51, and the fifth pipe 57 is used to discharge the gas adsorbed by the second adsorption column 52. A first control valve a is provided between the first compression device 4 and the first adsorption inlet 511; a third control valve c is provided between the first compression device 4 and the second adsorption inlet 521; a fifth control valve e is provided on the second pipeline 54; a second control valve b is provided on the fourth pipeline 56; a fourth control valve d is provided on the fifth pipeline 57; a sixth control valve f is provided between the first adsorption inlet 511 and the ammonia decomposition reaction device 3; and a seventh control valve g is provided between the second adsorption inlet 521 and the ammonia decomposition reaction device 3. The first compression device 4 is connected to the first adsorption inlet 511 of the first adsorption column 51 through the first control valve a; the first compression device 4 is connected to the second adsorption inlet 521 of the second adsorption column 52 through the third control valve c; the first adsorption inlet 511 of the first adsorption column 51 is connected to the gas inlet 31 of the ammonia decomposition reaction device 3 through the sixth control valve f; and the second adsorption inlet 521 of the second adsorption column 52 is connected to the gas inlet 31 of the ammonia decomposition reaction device 3 through the seventh control valve g.

[0058] To more effectively promote the decomposition reaction of residual ammonia and increase the hydrogen production of the entire system, preferably, a second compression device 6 is provided between the gas inlet 31 of the first adsorption device 5 and the ammonia decomposition reaction device 3. The first adsorption inlet 511 of the first adsorption column 51 is connected to the second compression device 6 through a sixth control valve f, and the second adsorption inlet 521 of the second adsorption column 52 is connected to the second compression device 6 through a seventh control valve g. Furthermore, to improve the compression effect of the second compression device 6, buffer tanks are provided at both the inlet and outlet ends of the second compression device 6.

[0059] After the mixed gas is compressed by the first compression device 4, it flows into the first adsorption device 5 through a pipeline. At this time, the first control valve a is opened, and the mixed gas passes through the first control valve a and enters the first adsorption column 51 for adsorption at room temperature. Subsequently, the second control valve b, the fifth control valve e, and the seventh control valve g are opened. After adsorption is completed, the mixed gas is discharged from the first adsorption column 51 through the second control valve b. At the same time, 5-15% of the mixed gas enters the second adsorption column 52 through the second pipeline 54 to purge the second adsorption column 52. The purged gas is discharged from the second adsorption column 52 through the seventh control valve g and enters the second compression device 6. When the first adsorption column 51 has completed adsorption and reached saturation, the first control valve a and the second control valve b are closed, and the third control valve c, the fifth control valve e, and the sixth control valve g are opened. Valve f allows the mixed gas, compressed by the first compression device 4, to enter the second adsorption column 52 for adsorption. Simultaneously, 5-15% of the mixed gas is introduced into the first adsorption column 51 through the second pipe 54 to purge the first adsorption column 51. At the same time, the fourth control valve d is opened to discharge the remaining mixed gas after adsorption by the second adsorption column 52 through the fourth control valve d. After purging, the mixed gas is discharged from the first adsorption column 51 through the sixth control valve f and enters the second compression device 6 for further compression. The compressed mixed gas enters the ammonia decomposition reaction device 3 to further decompose the residual ammonia in the mixed gas, thereby preventing the risk of ammonia being emitted into the air and causing air pollution. It also reduces the residual ammonia in the mixed gas and increases the hydrogen content in the mixed gas.

[0060] When the second adsorption column 52 is saturated and the first adsorption column 51 has been purged, adsorption can proceed again: first, the third control valve c, the fifth control valve e, and the sixth control valve f are opened, allowing the compressed mixed gas to pass through the second adsorption column 52, where it adsorbs the mixed gas and purges the first adsorption column 51; when the second adsorption column 52 reaches saturation, the third control valve c is closed, and the first control valve a, the fifth control valve e, and the seventh control valve g are opened, allowing the mixed gas to pass through the first adsorption column 51 for adsorption and purge the second adsorption column 52.

[0061] By employing multiple adsorption columns connected in parallel, and installing control valves between the adsorption outlets of adjacent adsorption columns, and connecting the adsorption inlet of each adsorption column to a compression device, adsorption and purging of the adsorption columns can be performed simultaneously. This ensures that the adsorption device continuously adsorbs the mixed gas, reducing the need to replace saturated adsorption columns and thus improving the adsorption effect and working efficiency of the adsorption device. Furthermore, by connecting the outlets of two adjacent adsorption columns and using the adsorbed mixed gas to purge another adsorption column, the mixed gas generated by the system is effectively utilized, reducing the system's demand for and consumption of external nitrogen, thereby reducing system energy loss, improving system energy utilization, and also reducing the emission of harmful gases. The purged gas can be further compressed and enter the ammonia decomposition reactor for decomposition reaction, improving the system's gas utilization rate, increasing the hydrogen content in the mixed gas, and reducing the ammonia content, achieving 100% ammonia recycling. The mixed gas after ammonia decomposition is adsorbed by the two adsorption columns in the first adsorption device 5, so that the mixed gas finally discharged from the first adsorption device 5 is a hydrogen-nitrogen mixed gas that has undergone deep adsorption and ammonia removal, reducing the emission of harmful gases. The ammonia decomposition hydrogen production system of this invention uses a mixed gas and valves to purge the adsorption column, eliminating the need for additional nitrogen purging and reducing system operating costs.

[0062] To further improve the purity of hydrogen produced by the ammonia decomposition hydrogen production system, while also increasing the system's utilization rate of tail gas, enhancing the system's adsorption effect, and reducing the system's overall energy consumption, according to... Figures 2-5 Optimize the system.

[0063] like Figure 2As shown, the system also includes a buffer device 7 and a second adsorption device 8. The second adsorption device 8 includes multiple adsorption columns arranged in parallel. The adsorption outlet of the adsorption column on the first adsorption device 5 is connected to one end of the buffer device 7, and the other end of the buffer device 7 is connected to the adsorption inlet of the adsorption column on the second adsorption device 8. Preferably, the second adsorption device 8 includes a third adsorption column 81 and a fourth adsorption column 82 arranged in parallel, and an eighth control valve h, a ninth control valve i, a tenth control valve j, an eleventh control valve k, a twelfth control valve m, a thirteenth control valve n, and a fourteenth control valve p disposed at the adsorption inlet and adsorption outlet of the second adsorption device 8. The third adsorption column 81 is provided with a third adsorption inlet 811 and a third adsorption outlet 812, and the fourth adsorption column 82 is provided with a fourth adsorption inlet 821 and a fourth adsorption outlet 822. A sixth pipe 83 is provided between the third adsorption inlet 811 and the fourth adsorption inlet 821. The third adsorption outlet 812 and the fourth adsorption outlet 822 are connected through a seventh pipe 84. An eighth pipe 85 is connected in parallel below the sixth pipe 83. A ninth pipe 86 is connected to the adsorption outlet 812, and a tenth pipe 87 is connected to the fourth adsorption outlet 822. The ninth pipe 86 is used to discharge the gas adsorbed by the third adsorption column 81, and the tenth pipe 87 is used to discharge the gas adsorbed by the fourth adsorption column 82. A thirteenth control valve n is installed on the sixth pipe 83 near the third adsorption column 81, and a fourteenth control valve p is installed on the sixth pipe 83 near the fourth adsorption column 82. An eighth control valve h is installed between the buffer device 7 and the third adsorption inlet 811, and a tenth control valve j is installed between the buffer device 7 and the fourth adsorption inlet 821. A twelfth control valve m is installed on the seventh pipe 84, a ninth control valve i is installed on the ninth pipe 86, and an eleventh control valve k is installed on the tenth pipe 87.

[0064] To better utilize the gas adsorbed by the third adsorption column 81 or the fourth adsorption column 82, and to reduce the harm of exhaust gases, especially nitrogen oxides, being directly emitted into the air, such as... Figure 3 As shown, the third adsorption inlet 811 of the third adsorption column 81 and the fourth adsorption inlet 821 of the fourth adsorption column 82 are respectively connected to the inlet of the combustion device 9, and the outlet of the combustion device 9 is connected to the ammonia decomposition reaction device 3. The combustion device 9 can heat and burn the gas used to purge the third adsorption column 81 and the fourth adsorption column 82 to generate combustion gas with a higher temperature. The combusted gas is then introduced into the ammonia decomposition reaction device 3, using the heat of the gas itself to provide heat for the ammonia decomposition process, so as to promote the ammonia in the ammonia decomposition reaction device 3 to undergo a faster and more complete decomposition reaction to generate hydrogen and nitrogen, thereby better reducing the energy consumption of the system.

[0065] Furthermore, such as Figure 4 and Figure 5As shown, the ninth pipe 86 and the tenth pipe 87 of the second adsorption device 8 are both connected to hydrogen energy terminal equipment, such as hydrogen fuel cells or hydrogen refueling stations. The ninth pipe 86 and the tenth pipe 87 of the second adsorption device 8 can introduce the gas adsorbed by the third adsorption column 81 and the fourth adsorption column 82 into the hydrogen energy terminal equipment for use as fuel. For example, Figure 5 As shown, when the hydrogen energy terminal device is a hydrogen fuel cell 10, one end of the hydrogen energy terminal device is connected to the combustion device 9, and the other end of the combustion device 9 is connected to the ammonia decomposition reaction device 3. The combustion device 9 can burn the exhaust gas emitted by the hydrogen fuel cell 10, and then introduce the burned gas into the ammonia decomposition reaction device 3 for heating ammonia. This not only effectively utilizes the exhaust gas of the hydrogen fuel cell, but also reduces the pollution of the environment caused by the exhaust gas emissions of the hydrogen fuel cell.

[0066] Similarly, when the first adsorption device 5 is connected to the second adsorption device 8, the mixed gas adsorbed by the first adsorption device 5 flows into the buffer device 7, and after being buffered by the buffer device 7, it is discharged into the second adsorption device 8. At this time, the eighth control valve h is opened first, and the mixed gas passes through the first control valve a and then enters the third adsorption column 81 for gas pressure adsorption. Then, the ninth control valve i, the twelfth control valve m, and the fourteenth control valve p are opened. After the adsorption is completed, the mixed gas is discharged from the third adsorption column 81 through the ninth control valve i. The mixed gas also purges the fourth adsorption column 82 through the twelfth control valve m, and then is discharged from the second adsorption device 8 through the fourteenth control valve p. When the third adsorption column 81 is saturated after adsorption, the eighth control valve h and the ninth control valve i are closed, and the tenth control valve j, the eleventh control valve k, the twelfth control valve m, and the thirteenth control valve n are opened, so that the buffered mixed gas enters the fourth adsorption column 82 for adsorption, and purges the third adsorption column 81 through the twelfth control valve m. The gas after purging is discharged from the third adsorption column 81 through the thirteenth control valve n.

[0067] After the fourth adsorption column 82 is saturated and the third adsorption column 81 is purged, adsorption can be performed again: first, the tenth control valve j and the twelfth control valve m are opened, so that the compressed mixed gas passes through the fourth adsorption column 82 for adsorption and purges the third adsorption column 81; when the fourth adsorption column 82 reaches saturation, the tenth control valve j is closed, and the eighth control valve h and the twelfth control valve m are opened, so that the mixed gas passes through the third adsorption column 81 for adsorption and purges the fourth adsorption column 82.

[0068] In addition, the present invention also discloses a hydrogen production method using the ammonia decomposition hydrogen production system, the specific steps of which are as follows:

[0069] S1. The liquid ammonia in the ammonia storage device 1 is introduced into the heat exchange device 2, and the liquid ammonia is heated to above 550°C;

[0070] S2. Ammonia gas at or above 550°C in heat exchanger 2 is introduced into ammonia decomposition reaction device 3 to carry out ammonia decomposition reaction.

[0071] S3. The mixed gas after being decomposed by the ammonia decomposition reaction device 3 is discharged from the ammonia decomposition reaction device 3 and introduced into the heat exchange device 2 to cool the mixed gas to room temperature.

[0072] S4. The mixed gas cooled to room temperature is introduced into the first compression device 4 for compression;

[0073] S5. The mixed gas compressed by the first compression device 4 is introduced into the first adsorption column 51 of the first adsorption device 5, so that the first adsorption column 51 adsorbs the mixed gas until the first adsorption column 21 reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the first adsorption column 51 is passed to the second adsorption column 52 to purge the second adsorption column 52.

[0074] S6. After the purging is completed, the mixed gas is discharged from the second adsorption column 52 and reintroduced into the ammonia decomposition reaction device 3 to carry out the ammonia decomposition reaction.

[0075] S7. The mixed gas compressed by the first compression device 4 is introduced into the second adsorption column 52 of the first adsorption device 5, so that the second adsorption column 52 adsorbs the mixed gas until the second adsorption column 52 reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the second adsorption column 52 is passed to the first adsorption column 51 to purge the first adsorption column 51.

[0076] S8. After the purging is completed, the mixed gas is discharged from the second adsorption column 52 and reintroduced into the ammonia decomposition reaction device 3 to carry out the ammonia decomposition reaction.

[0077] Steps S9, S5-S8 are repeated in a loop.

[0078] In step S5, the first control valve a of the first adsorption device 5 is opened, and the mixed gas is introduced into the first adsorption column 51 through the corresponding connected pipe. At the same time, the fifth control valve e of the first adsorption device 5 is opened, and 5-15% of the mixed gas is introduced into the second adsorption column 52 for purging. The remaining gas is discharged from the first adsorption column 51 through the second control valve b for subsequent gas collection and utilization. In step S6, the purged gas is discharged from the first adsorption device 5 through the seventh control valve g and enters the ammonia decomposition reaction device 3. In step S7, the third control valve c of the first adsorption device 5 is opened, and the mixed gas is introduced into the second adsorption column 52 through the corresponding connected pipe for adsorption. At the same time, the fifth control valve e of the first adsorption device 5 is opened, and 5-15% of the mixed gas is purged through the fifth control valve e. The remaining gas is discharged through the fourth control valve d. In step S8, the purged gas is discharged from the first adsorption device 5 through the sixth control valve f and enters the ammonia decomposition reaction device 3.

[0079] Similarly, the second adsorption column 52 can be adsorbed first and the first adsorption column 51 can be purged first; when the second adsorption column 52 is saturated, the first adsorption column 51 can be adsorbed, while the second adsorption column 52 is purged at the same time; after purging, the purged gas is introduced into the ammonia decomposition reaction device 3 through the seventh control valve g and the sixth control valve f to complete the reuse of the purging gas.

[0080] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A hydrogen production system based on ammonia decomposition reaction, comprising an ammonia storage device (1), a heat exchange device (2), an ammonia decomposition reaction device (3), a first compression device (4), and a first adsorption device (5), characterized in that: The outlet of the ammonia storage device (1) is connected to the gas inlet (31) of the ammonia decomposition reaction device (3) through the cold liquid channel on the heat exchange device (2). The gas outlet (32) of the ammonia decomposition reaction device (3) is connected to the first compression device (4) through the gas channel on the heat exchange device (2). The liquid ammonia discharged from the ammonia storage device (1) and the mixed gas discharged from the ammonia decomposition reaction device (3) exchange heat through the heat exchange device (2) and the gas after heat exchange is introduced into the first compression device (4). The first adsorption device (5) includes multiple adsorption columns arranged in parallel. The outlet of the first compression device (4) is simultaneously connected to the adsorption inlet of the multiple adsorption columns arranged in parallel. A control valve is provided on the pipeline between the adsorption inlet of each adsorption column and the first compression device (4). The adsorption outlets of the multiple adsorption columns are connected to each other. A control valve is provided between the adsorption outlets of two adjacent adsorption columns. The adsorption inlet of each adsorption column is also connected to the gas inlet (31) of the ammonia decomposition reaction device (3) through a pipeline. A control valve is provided on the pipeline between the adsorption inlet of each adsorption column and the ammonia decomposition reaction device (3). When the control valve located between the adsorption outlets of two adjacent adsorption columns is opened, the mixed gas after being adsorbed by the adsorption column can be introduced into the ammonia decomposition reaction device (3) through the adsorption inlet of one of the adsorption columns. The heat exchange device (2) includes a first heat exchanger (21) and a second heat exchanger (22). The first heat exchanger (21) is provided with a first cold liquid inlet (211), a first cold liquid outlet (212), a first hot gas inlet (213), and a first hot gas outlet (214). The first cold liquid inlet (211) and the first cold liquid outlet (212) are connected as a pair, and the first hot gas inlet (213) and the first hot gas outlet (214) are connected as a pair. The second heat exchanger (22) is provided with a second cold gas inlet (221), a second cold gas outlet (222), a second hot gas inlet (223), and a second hot gas outlet (224). The second cold gas inlet (221) and the second hot gas outlet (224) are connected as a pair. The second cold air outlet (222) is connected to the second hot air inlet (223) and the second hot air outlet (224) are connected to the second hot air outlet (224); the liquid outlet of the ammonia storage device (1) is connected to the gas inlet (31) of the ammonia decomposition reaction device (3) in sequence through the first cold liquid inlet (211), the first cold liquid outlet (212), the second cold air inlet (221) and the second cold air outlet (222); the gas outlet (32) of the ammonia decomposition reaction device (3) is connected to the inlet of the first compression device (4) in sequence through the second hot air inlet (223), the second hot air outlet (224), the first hot air inlet (213) and the first hot air outlet (214); A second compression device (6) is also provided on the pipeline between the gas inlet of the first adsorption device (5) and the ammonia decomposition reaction device (3).

2. The ammonia decomposition reaction hydrogen production system according to claim 1, characterized in that: A regulating valve (23) is provided on the pipeline between the first cold liquid outlet (212) and the second cold air inlet (221); an air-cooling device (24) is also provided on the pipeline between the second hot air outlet (224) and the first hot air inlet (213).

3. The ammonia decomposition reaction hydrogen production system according to claim 2, characterized in that: The inlet and outlet ends of the first compression device (4) and the inlet and outlet ends of the second compression device (6) are all provided with buffer tanks.

4. The ammonia decomposition reaction hydrogen production system according to claim 1, characterized in that: The first adsorption device (5) includes a first adsorption column (51) and a second adsorption column (52) arranged in parallel, and a first control valve (a), a second control valve (b), a third control valve (c), a fourth control valve (d), a fifth control valve (e), a sixth control valve (f), and a seventh control valve (g) arranged at the adsorption inlet and adsorption outlet of the first adsorption device (5). The first adsorption column (51) is provided with a first adsorption inlet (511) and a first adsorption outlet (512), and the second adsorption column (52) is provided with a second adsorption inlet (521) and a second adsorption outlet (522). A first pipe (53) is provided between the first adsorption inlet (511) and the second adsorption inlet (521), and the first adsorption outlet (512) and the second adsorption outlet (522) are connected through a second pipe (54). The lower part of the first pipe (53) is connected to the second adsorption outlet (522). A third pipe (55) is connected to the first adsorption outlet (512), a fourth pipe (56) is provided on the first adsorption outlet (512), and a fifth pipe (57) is provided on the second adsorption outlet (522); a first control valve (a) is provided between the first compression device (4) and the first adsorption inlet (511), a third control valve (c) is provided between the first compression device (4) and the second adsorption inlet (521), a fifth control valve (e) is provided on the second pipe (54), a second control valve (b) is provided on the fourth pipe (56), a fourth control valve (d) is provided on the fifth pipe (57), a sixth control valve (f) is provided between the first adsorption inlet (511) and the ammonia decomposition reaction device (3), and a seventh control valve (g) is provided between the second adsorption inlet (521) and the ammonia decomposition reaction device (3).

5. The ammonia decomposition reaction hydrogen production system according to claim 1, characterized in that: The system also includes a buffer device (7) and a second adsorption device (8). The second adsorption device (8) includes multiple adsorption columns arranged in parallel. The adsorption outlet of the adsorption column on the first adsorption device (5) is connected to one end of the buffer device (7), and the other end of the buffer device (7) is connected to the adsorption inlet of the adsorption column on the second adsorption device (8).

6. The ammonia decomposition reaction hydrogen production system according to claim 5, characterized in that: The second adsorption device (8) includes a third adsorption column (81) and a fourth adsorption column (82) arranged in parallel, and an eighth control valve (h), a ninth control valve (i), a tenth control valve (j), an eleventh control valve (k), a twelfth control valve (m), a thirteenth control valve (n), and a fourteenth control valve (p) arranged at the adsorption inlet and adsorption outlet of the second adsorption device (8). The third adsorption column (81) is provided with a third adsorption inlet (811) and a third adsorption outlet (812), and the fourth adsorption column (82) is provided with a fourth adsorption inlet (821) and a fourth adsorption outlet (822). A sixth pipe (83) is provided between the third adsorption inlet (811) and the fourth adsorption inlet (821), and the third adsorption outlet (812) and the fourth adsorption outlet (822) are connected by a seventh pipe (84). Below (83), there is an eighth pipe (85), the third adsorption outlet (812) is connected to a ninth pipe (86), and the fourth adsorption outlet (822) is connected to a tenth pipe (87); the sixth pipe (83) is provided with a thirteenth control valve (n) near the third adsorption column (81), the sixth pipe (83) is provided with a fourteenth control valve (p) near the fourth adsorption column (82), the buffer device (7) is provided with an eighth control valve (h) between the buffer device (7) and the third adsorption inlet (811), the buffer device (7) is provided with a tenth control valve (j) between the buffer device (7) and the fourth adsorption inlet (821), the seventh pipe (84) is provided with a twelfth control valve (m), the ninth pipe (86) is provided with a ninth control valve (i), and the tenth pipe (87) is provided with an eleventh control valve (k).

7. The ammonia decomposition reaction hydrogen production system according to claim 6, characterized in that: The system also includes a combustion device (9), the third adsorption inlet (811) of the third adsorption column (81) and the fourth adsorption inlet (821) of the fourth adsorption column (82) are respectively connected to the inlet of the combustion device (9), and the outlet of the combustion device (9) is connected to the ammonia decomposition reaction device (3).

8. The ammonia decomposition reaction hydrogen production system according to claim 7, characterized in that: The system also includes a hydrogen fuel cell (10), the adsorption outlet of the first adsorption device (5) is connected to the hydrogen fuel cell (10), the outlet of the hydrogen fuel cell (10) is connected to the inlet of the combustion device (9), and the outlet of the combustion device (9) is connected to the ammonia decomposition reaction device (3).

9. A method for producing hydrogen using the ammonia decomposition reaction hydrogen production system according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Introduce liquid ammonia into the heat exchanger (2) and heat the liquid ammonia to above 550°C; S2. Introduce ammonia gas into the ammonia decomposition reaction device (3) to carry out the ammonia decomposition reaction; S3. Discharge the decomposed mixed gas from the ammonia decomposition reaction device (3) and cool it to room temperature; S4. The cooled mixed gas is introduced into the first compression device (4) for compression; S5. The mixed gas compressed by the first compression device (4) is introduced into the first adsorption column (51) of the first adsorption device (5) so that the first adsorption column (51) adsorbs the mixed gas until the first adsorption column (51) reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the first adsorption column (51) is passed to the second adsorption column (52) to purge the second adsorption column (52). S6. After the purging is completed, the mixed gas is discharged from the second adsorption column (52) and re-introduced into the ammonia decomposition reaction device (3) to carry out the ammonia decomposition reaction. S7. The mixed gas compressed by the first compression device (4) is introduced into the second adsorption column (52) of the adsorption device, so that the second adsorption column (52) adsorbs the mixed gas until the second adsorption column (52) reaches saturation. At the same time as adsorption, 5 to 15% of the mixed gas in the second adsorption column (52) is passed to the first adsorption column (51) to purge the first adsorption column (51). S8. After the purging is completed, the mixed gas is discharged from the first adsorption column (51) and re-introduced into the ammonia decomposition reaction device (3) to carry out the ammonia decomposition reaction. Steps S9, S5-S8 are repeated in a loop.

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