Method for producing hydrogen by promoting ammonia cracking through multistage selective hydrogen oxidation and adiabatic reaction system

Abstract

The invention discloses a method for producing hydrogen by promoting ammonia cracking through multistage selective hydrogen oxidation and an adiabatic reaction system. The method comprises the following steps: A, heating ammonia to convert the ammonia into ammonia gas, then promoting decomposition of the ammonia through a first adiabatic catalytic reaction unit to obtain hydrogen and unconverted ammonia, and enabling the hydrogen and unconverted ammonia to enter a subsequent adiabatic catalytic reaction unit; b, introducing oxygen-containing gas into each subsequent adiabatic catalytic reaction unit, reacting the introduced oxidizing atmosphere with hydrogen in the output material, and releasing heat to promote the temperature rise of the material so as to promote the decomposition of ammonia; and C, repeating the process of the step B, and introducing oxygen-containing gas into each subsequent adiabatic catalytic reaction unit for multiple times to further promote ammonia decomposition until the decomposition rate of the ammonia reaches the standard. The device has the advantages of being capable of meeting the requirements of different flow rates of hydrogen in the downstream, low in manufacturing cost, compact in structure, flexible to operate and the like, is suitable for both mobile hydrogen production and fixed hydrogen production, and can adopt air and oxygen as an oxidizing medium.

Description

Technical Field

[0001] The present invention relates to an ammonia cracking hydrogen production technology, and more specifically to a multi-stage selective hydrogen oxidation promoted ammonia cracking hydrogen production method and an adiabatic reaction system. Background Art

[0002] Ammonia is not only an important chemical, but also regarded as an important energy carrier, for example, it can be used as a future shipping fuel; in addition, ammonia is also an excellent hydrogen carrier with a high hydrogen storage capacity (17.6%). Under the same volume, the hydrogen content of liquid ammonia is higher than that of liquid hydrogen. However, ammonia is a very stable molecule, and its decomposition reaction is reversible and endothermic, requiring a relatively high temperature to completely decompose. If it is desired to decompose at a lower temperature, noble metal catalysts (usually 400 o °C) are often needed, which greatly increases the cost of hydrogen production. Common non-precious metals such as Fe, Co, and Ni can also catalyze ammonia decomposition, but their activity is not high, and a relatively high reaction temperature (usually 600 o °C) is required, and it is difficult to reach a high temperature above 600 o °C by external heating.

[0003] To address this problem, the corresponding heat can be obtained by burning ammonia in oxygen to heat the raw material gas. For example, Topsøe of Denmark proposed a patent for an invention with the publication number CN110799451B and the invention name of a method for autothermal cracking of ammonia. The technical solution adopted is: non-catalytically partially oxidizing ammonia with a gas containing oxygen into a process gas containing nitrogen, water, a certain amount of nitrogen oxides, and residual ammonia; cracking at least a part of the residual ammonia in the process gas into hydrogen and nitrogen by contacting with a nickel-containing catalyst, and at the same time reacting a certain amount of nitrogen oxides with a part of the hydrogen formed during the cracking of the process gas by contacting the process gas with the nickel-containing catalyst to be reduced to nitrogen and water, and taking out a product gas containing a certain amount of nitrogen and hydrogen.

[0004] However, the disadvantage of this autothermal ammonia cracking hydrogen production technology is that oxygen is added to the reactor at one time to react with ammonia, and the large amount of heat released by combustion causes the temperature of the raw material gas to rise sharply (700 - 1100 degrees Celsius), which requires a high temperature resistance performance for the reactor; at the same time, the high-temperature combustion of ammonia will inevitably generate a large amount of NO X, and subsequent processing is required through specialized equipment. This self-heating reaction device is more suitable for occasions where the hydrogen consumption scale is large and the hydrogen demand and raw material supply are stable (such as chemical plants), and is not suitable for being made into a mobile device (such as vehicles, ships, etc. in the mobile field and small distributed hydrogen production devices), nor is it suitable for occasions where the hydrogen demand is unstable (such as applications in the mobile field of vehicles, ships, etc.). Therefore, the current technical pain points are mainly that an external NOx treatment device is required, the device scale is large, and it is suitable for fixed hydrogen production. This mode is not applicable to distributed energy systems or mobile field applications, such as the shipping field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for promoting the decomposition of ammonia to obtain a mixture of hydrogen and nitrogen, which is suitable for both mobile hydrogen production and fixed hydrogen production, and can use either air or oxygen as the oxidation medium, as well as an adiabatic reaction system for multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production.

[0006] To solve the above technical problems, the multi-stage selective hydrogen oxidation method for promoting ammonia cracking for hydrogen production according to the present invention includes the following steps: A. Heat ammonia to a suitable temperature to convert it into ammonia gas or a mixture of ammonia and hydrogen, and then promote the decomposition of ammonia through the first adiabatic catalytic reaction unit to obtain a mixture containing hydrogen and unreacted ammonia, which enters the subsequent adiabatic catalytic reaction units; B. Introduce an oxygen-containing gas into each subsequent adiabatic catalytic reaction unit, and the oxygen introduced reacts with the hydrogen in the mixed gas output from the adiabatic catalytic reaction unit in step A. The heat released by the oxidation of hydrogen raises the temperature of the mixed gas to a temperature suitable for ammonia cracking, thereby promoting the catalytic cracking of ammonia; C. Repeat the process of step B, and introduce an oxygen-containing gas into each subsequent adiabatic catalytic reaction unit multiple times to react with hydrogen to generate heat, increase the temperature of the mixed gas to further promote the catalytic cracking of ammonia until the decomposition rate of ammonia reaches the standard.

[0007] Further, the oxygen-containing gas in step B is pure oxygen or a mixture containing oxygen and one or more other gases, which can be nitrogen, water vapor, carbon dioxide, and their mixtures. The concentration of oxygen can be between 1% and 99.99%, and the molar ratio of oxygen / NH 3 is between 0.05 and 0.2.

[0008] Still further, the reaction temperature in step A is 350 o °C to 900 o °C, and the more suitable temperature is 500 to 700 o °C, and the pressure of the reactor can be between atmospheric pressure and 6.0 MPa.

[0009] Furthermore, a solid catalyst is loaded in the adiabatic catalytic reaction unit, and the active components of the solid catalyst are Co, Ni or Fe.

[0010] Furthermore, the catalyst is a monazite-type structural catalyst or a shaped catalyst.

[0011] Furthermore, the concentration of oxygen in step B is 1% - 99.99%.

[0012] An adiabatic reaction system for the above-mentioned multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method, comprising a primary adiabatic reactor as the first adiabatic catalytic reaction unit, and at least two N secondary adiabatic reactors connected in sequence behind the primary adiabatic reactor as subsequent adiabatic catalytic reaction units. An inlet end of the primary adiabatic reactor is provided with a primary heat exchanger for heating ammonia to a suitable temperature to convert it into superheated ammonia gas. A secondary heat exchanger is provided between each of the secondary adiabatic reactors and at the end of the last secondary heat exchanger. An oxygen-containing gas inlet is also provided on each of the secondary adiabatic reactors.

[0013] An adiabatic reaction system for the above-mentioned multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method, comprising an adiabatic reactor having multiple catalyst beds and a heat exchanger connected to an inlet end of the adiabatic reactor for heating ammonia to a suitable temperature to convert it into superheated ammonia gas. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, and at least one layer of the subsequent catalyst beds in the adiabatic reactor serves as subsequent adiabatic catalytic reaction units. An oxygen-containing gas inlet is provided between the first adiabatic catalytic reaction unit and the subsequent adiabatic catalytic reaction units in the adiabatic reactor.

[0014] An adiabatic reaction system for the above-mentioned multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method, comprising an adiabatic reactor having multiple catalyst beds arranged in sequence from top to bottom and a heat exchanger connected to an inlet end of the adiabatic reactor for heating ammonia to a suitable temperature to convert it into superheated ammonia gas. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, and the subsequent catalyst beds in the adiabatic reactor serve as subsequent adiabatic catalytic reaction units. An oxygen-containing gas inlet is provided between adjacent catalyst beds in the adiabatic reactor.

[0015] An adiabatic reaction system for the above-mentioned multi-stage selective hydrogen oxidation promoted ammonia cracking hydrogen production method, which serially connects at least one independent adiabatic reactor, an adiabatic reactor with multiple catalyst beds arranged successively from top to bottom, and / or an adiabatic reactor with multiple catalyst beds. The first adiabatic reactor serves as the first adiabatic catalytic reaction unit, and the remaining adiabatic reactors serve as subsequent adiabatic catalytic reaction units. The inlet end of the first adiabatic catalytic reaction unit is provided with a primary heat exchanger for heating ammonia to a suitable temperature to convert it into superheated ammonia gas. A secondary heat exchanger is provided at the end between each subsequent adiabatic catalytic reaction unit. An oxygen-containing gas inlet is also provided on each of the subsequent adiabatic catalytic reaction units.

[0016] The advantages of the present invention are as follows: The oxygen-containing gas is added to the reaction unit in segments to selectively oxidize hydrogen in the mixture of ammonia and hydrogen (hydrogen can be recycled or generated by ammonia decomposition) into water, thereby providing heat to promote the decomposition of ammonia. (The purpose of adding oxygen in segments is to control the oxidation reaction and gradually release the heat of the oxidation reaction, so that the temperature of the raw material gas can be controlled at a lower level, reducing and even avoiding the direct oxidation of ammonia, thereby reducing the generation of NO X .); As the number of adiabatic segments or the number of reactors increases, ammonia gradually approaches complete conversion; The outlet product of the last or one reactor in the reactor structure can be combusted or the ammonia therein can be removed according to the requirements of the downstream, and finally a mixture of relatively pure hydrogen and nitrogen can be obtained; In this process, there is no need to use an ammonia decomposition catalyst containing precious metals, and the high-efficiency conversion of ammonia is completely achieved by common iron, cobalt or nickel catalysts; Although there are multiple reactors, the volume and height of each reactor can be freely adjusted and can be adjusted according to different hydrogen production amounts; The design of introducing oxygen in segments can control the temperature of the raw material gas in the reactor at a lower level, so that oxygen only reacts with hydrogen to generate water and release heat, while avoiding the direct reaction of ammonia with oxygen to generate NO X ; Since the structure of each sub-reactor can be freely adjusted, the entire system can be made into a structured system, similar to a container, with a compact structure and can be used in mobile field applications; Compared with a single autothermal ammonia cracking reactor, the temperature in the reactor is lower and the temperature distribution is more moderate, and the cost is low; Reacting through the above process method and adiabatic reaction system, which promotes ammonia decomposition through multiple adiabatic reactors or multiple sections of adiabatic reactors. An oxygen-containing atmosphere is introduced in sections at the inlet of each reactor or in the middle sections between reactors. The introduced oxygen-containing atmosphere reacts with hydrogen in the material coming from upstream, and the released heat promotes the gradual decomposition of ammonia. After introducing the oxygen-containing atmosphere into the system multiple times, almost complete decomposition of ammonia can be promoted, which can meet the downstream demand for hydrogen with different flow rates. The staged introduction of oxygen can control the temperature of the raw material gas in the reactor at a relatively low level, so that oxygen only reacts with hydrogen to generate water and release heat, while avoiding the direct reaction of ammonia with oxygen to generate NO X The temperature in the reactor is relatively low and the temperature distribution is relatively mild, with low cost. This system has the advantages of low cost, compact structure, and flexible operation. The hydrogen generated by selective oxidation provides heat, thus promoting the process of ammonia decomposition to obtain a hydrogen-nitrogen mixture. It is suitable for both mobile hydrogen production and fixed hydrogen production, and can use either air or oxygen as the oxidation medium. Brief Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the second embodiment of the present invention; Figure 2 It is a schematic structural diagram of the third embodiment of the present invention; Figure 3 It is a schematic structural diagram of the fourth embodiment of the present invention; Detailed Description of the Invention

[0018] The following further describes in detail the method for producing hydrogen by promoting ammonia cracking through multi-stage selective hydrogen oxidation and the adiabatic reaction system of the present invention in conjunction with the drawings and specific embodiments. Embodiment

[0019] As shown in the figure, the method for producing hydrogen by promoting ammonia cracking through multi-stage selective hydrogen oxidation in this embodiment. The present invention is a method proposed for the efficient conversion of ammonia on non-noble metal catalysts. The main raw materials are superheated ammonia preheated to a certain temperature or a mixture of superheated ammonia and hydrogen, which are passed through several adiabatic catalytic reactors or several catalytic layers in an adiabatic reactor, or a combination thereof; a certain amount of oxygen-containing gas is introduced at the inlet of each section to react with hydrogen in the raw materials to form water to promote the temperature rise of the materials. After the heated materials pass through the catalytic bed layer, ammonia decomposes. The above process is gradually advanced, and finally ammonia is completely decomposed. It includes the following steps: A. Heat a part of the ammonia in the raw material ammonia to an appropriate temperature by external heating, or heat the raw material gas to an appropriate temperature by adding a small amount of oxygen to burn with a part of the ammonia to generate heat; or add a small amount of hydrogen to the raw material ammonia and react with the subsequently added oxygen to heat the raw material gas to an appropriate temperature; then promote the decomposition of ammonia through the first adiabatic catalytic reaction unit, and the mixed gas containing hydrogen, nitrogen and unreacted ammonia enters the subsequent adiabatic catalytic reaction units. Since the cracking of ammonia is an endothermic reaction, the temperature of the mixed gas leaving the reactor will drop to a temperature unsuitable for ammonia cracking; B. Introduce an oxygen-containing gas into each subsequent adiabatic catalytic reaction unit (i.e., each adiabatic catalytic reaction unit after the first adiabatic catalytic reaction unit). The introduced oxygen reacts with the hydrogen in the mixed gas output from the adiabatic catalytic reaction unit in step A. The heat released by the oxidation of hydrogen raises the temperature of the mixed gas to a temperature suitable for ammonia cracking (i.e., achieving rapid mixing and reacting quickly with the hydrogen in the raw material to form water), promoting the temperature rise of the material, and thus promoting the catalytic cracking of ammonia; C. Repeat the process of step B. Pass the oxygen-containing gas into each subsequent adiabatic catalytic reaction unit multiple times to further promote ammonia decomposition until the decomposition rate of ammonia reaches more than 80%.

[0020] To achieve this goal, a solid catalyst can be loaded in the adiabatic catalytic reaction unit. The active components of the solid catalyst are Co, Ni or Fe, which can be supported on an oxide carrier. The catalyst can be a structured catalyst (monazite type) or a shaped catalyst prepared by traditional shaping methods.

[0021] Among them, the adiabatic catalytic reaction unit can be operated at a pressure from atmospheric pressure to 60 kg. The lowest temperature in the adiabatic catalytic reaction unit is not less than 350 o C, and the highest temperature does not exceed 900 o C; the oxygen-containing gas is pure oxygen or a mixture containing oxygen and one or more other gases, and this gas can be nitrogen, water vapor, carbon dioxide, etc. The concentration of oxygen can be in the range of 1% - 99.99%. The molar ratio of oxygen / NH 3 is in the range of 5 - 20%. Examples

[0022] An adiabatic reaction system for implementing the multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method in Example 1, comprising a primary adiabatic reactor as the first adiabatic catalytic reaction unit, and at least two N secondary adiabatic reactors connected in sequence behind the primary adiabatic reactor as subsequent adiabatic catalytic reaction units. The number of secondary adiabatic reactors is preferably 2 - 6. The inlet end of the primary adiabatic reactor is provided with a primary heat exchanger for heating ammonia to a suitable temperature to convert it into hot ammonia. A secondary heat exchanger is provided between each secondary adiabatic reactor and at the end of the last secondary heat exchanger. An oxygen-containing gas inlet is also provided on each secondary adiabatic reactor.

[0023] In this embodiment, the process equipment consists of a first (the first) adiabatic fixed-bed reactor, a first off-reactor heat exchanger, a second adiabatic fixed-bed reactor, a second off-reactor heat exchanger, a third adiabatic fixed-bed reactor, a third off-reactor heat exchanger, a fourth adiabatic fixed-bed reactor, a waste heat boiler, and a post-heat exchanger in sequence.

[0024] The specific process is as follows. As Figure 1 shown, ammonia is heated to a suitable temperature to convert it into hot ammonia, and then the decomposition of ammonia is promoted through the primary adiabatic reactor, obtaining hydrogen and unreacted ammonia which enter the second stage (i.e., subsequent secondary adiabatic reactors). An appropriate amount of oxygen is introduced to react with hydrogen to generate water, and heat is released to promote the temperature rise of the material, thereby further promoting the decomposition of ammonia. The above process is repeated until the decomposition rate of ammonia reaches more than 80%. For the two adjacent adiabatic reactors, the inlet temperature of the reactor can be adjusted by heating with the corresponding heat exchanger.

[0025] Example

[0026] This embodiment is an adiabatic reaction system for implementing the multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method in Example 1, comprising an adiabatic reactor with multiple catalyst beds and a heat exchanger connected to the inlet end of the adiabatic reactor for heating ammonia to a suitable temperature to convert it into hot ammonia. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, and at least one layer of catalyst beds in the subsequent section of the adiabatic reactor serves as subsequent adiabatic catalytic reaction units. An oxygen-containing gas inlet is provided between the first adiabatic catalytic reaction unit and the subsequent adiabatic catalytic reaction units in the adiabatic reactor. In this embodiment, an adiabatic reactor is used, and there are multiple catalyst beds in this adiabatic reactor. An inter-stage heat exchanger is provided between each catalyst bed. After the reactor outlet material passes through the waste heat boiler and the post-heat exchanger, a mixture of hydrogen and nitrogen is obtained through purification; the number of catalyst beds is at least 2 and no more than 6 sections; by Figure 2It can be seen that this solution is an adiabatic reactor with inter-stage heat exchange. The figure shows the introduction of oxygen-containing gas between two catalyst beds (the inter-stage heat exchanger is not shown in the figure, which is located between the oxygen-containing gas inlet and below the gas distribution plate and above the second catalyst bed). Example

[0027] This example is an adiabatic reaction system for implementing the multi-stage selective hydrogen oxidation to promote ammonia cracking for hydrogen production method in Example 1, including an adiabatic reactor with multiple catalyst beds arranged in sequence from top to bottom and a heat exchanger connected to the inlet end of the adiabatic reactor for heating ammonia to a suitable temperature to convert it into hot ammonia gas. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, and the subsequent catalyst beds in the adiabatic reactor serve as subsequent adiabatic catalytic reaction units. An oxygen-containing gas inlet is provided between adjacent catalyst beds in the adiabatic reactor. Among them, there are multiple catalyst beds in the adiabatic reactor, and heat exchange occurs between the catalyst beds. The heat exchange method can be to set an inter-stage heat exchanger or raw material quench heat exchange. The number of catalyst bed segments is 2 - 6 segments. Part of the raw material reacts through the first catalyst bed and then is directly mixed with part of the raw material to cool down to the inlet temperature of the second catalyst bed and enters the second catalyst bed. The material passing through the second catalyst bed is mixed with part of the raw material again to reach the third catalyst bed. The material leaving the third catalyst bed is mixed and reacted with part of the raw material again, passes through the fourth bed at a certain temperature, then passes through a waste heat boiler and a post-heat exchanger, and then enters the refining unit; Figure 3 It can be seen that it shows four catalyst beds in an adiabatic reactor and the introduction of oxygen-containing gas at three places. For simplicity, the heat exchanger between the catalyst beds is not shown, and the quench of the hot mixed gas leaving the catalyst bed with part of the raw material is also not shown. Example

[0028] This example mainly involves the combination of Examples 2 - 4. The specific structure is: at least one independent adiabatic reactor, an adiabatic reactor with multiple catalyst beds arranged in sequence from top to bottom, and / or an adiabatic reactor with multiple catalyst bed segments are connected in series in sequence. The first adiabatic reactor serves as the first adiabatic catalytic reaction unit, and the remaining adiabatic reactors serve as subsequent adiabatic catalytic reaction units. A primary heat exchanger for heating ammonia to a suitable temperature to convert it into superheated ammonia gas is provided at the inlet end of the first adiabatic catalytic reaction unit. A secondary heat exchanger is provided at the end between each subsequent adiabatic catalytic reaction unit. An oxygen-containing gas inlet is also provided on each subsequent adiabatic catalytic reaction unit. For the catalyst in the adiabatic reactor, the main active components can be Ni, Co, or Fe, or a combination of the above active metals, as well as a combination of the above active metals and other promoters; the catalyst can be a structured catalyst or a general shaped catalyst.

[0029] That is, the flow direction of the fluid in the adiabatic reactor can be axial, radial or axial-radial. It can be fed from the upper part or the lower part. The material can enter the reactor bed from the reactor wall and finally converge in the central flow tube or the central distributed flow tube and flow towards the wall through the catalyst bed. It can be summarized as follows: the process of the adiabatic reactor can be multiple adiabatic reactors or a single adiabatic reactor with multiple catalyst beds. Inter-stage heat exchange reactors can be used between multiple catalyst beds, or it can be directly obtained by mixing the raw material at a lower temperature with the outlet material of the upper catalyst bed. Multiple adiabatic reactors can be connected in series, with multiple catalyst beds in each adiabatic reactor, and oxygen-containing gas is added to the catalyst beds. For the series connection mode of multiple adiabatic reactors, the adiabatic fixed bed can be an axial fixed bed, a radial fixed bed or an axial-radial fixed bed. For a single adiabatic reactor process, the fluid flow direction in the adiabatic reactor can be radial, axial or axial-radial.

[0030] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for producing hydrogen by multi-stage selective hydrogen oxidation to promote ammonia cracking, characterized in that: The following steps are involved: A. Heating ammonia to a suitable temperature to convert it into ammonia gas or a mixture of ammonia and hydrogen, and then promoting the decomposition of ammonia through a first adiabatic catalytic reaction unit to obtain ammonia containing hydrogen gas and unconverted ammonia and enter a subsequent adiabatic catalytic reaction unit; B. introducing oxygen-containing gas into each subsequent adiabatic catalytic reaction unit, the introduced oxygen reacts with hydrogen in the mixed gas output from the adiabatic catalytic reaction unit in step A, and the heat released by the oxidation of hydrogen raises the temperature of the mixed gas to a temperature suitable for ammonia cracking, thereby promoting the catalytic cracking of ammonia; C. Repeat the process of step B, and introduce oxygen-containing gas into each subsequent adiabatic catalytic reaction unit for multiple times to react with hydrogen to generate heat, thereby increasing the temperature of the mixed gas to further promote the catalytic cracking of ammonia, until the decomposition rate of ammonia reaches the standard.

2. The method for producing hydrogen by multi-stage selective hydrogen oxidation promoting ammonia cracking according to claim 1, characterized in that: The oxygen-containing gas in step B is pure oxygen or a mixture containing oxygen and one or more other gases.

3. The method for producing hydrogen by multi-stage selective hydrogen oxidation promoting ammonia cracking according to claim 1, characterized in that: The reaction temperature in step A is 350 o C~900 o C.

4. The method for producing hydrogen by multi-stage selective hydrogen oxidation promoting ammonia cracking according to claim 1, characterized in that: The adiabatic catalytic reaction unit is loaded with a solid catalyst, and the active component of the solid catalyst is Co, Ni or Fe.

5. The method for producing hydrogen by multi-stage selective hydrogen oxidation promoting ammonia cracking according to claim 4, characterized in that: The catalyst is a structured catalyst or a shaped catalyst.

6. The method for producing hydrogen by multi-stage selective hydrogen oxidation promoting ammonia cracking according to claim 1, characterized in that: The concentration of oxygen in step B is 1%-99.99%.

7. An adiabatic reaction system for the multi-stage selective hydrogen oxidation-promoted ammonia cracking hydrogen production method according to claims 1-6, characterized in that: The invention comprises a primary adiabatic reactor as the first adiabatic catalytic reaction unit, and at least two N secondary adiabatic reactors connected in sequence behind the primary adiabatic reactor as subsequent adiabatic catalytic reaction units. The inlet end of the primary adiabatic reactor is provided with a primary heat exchanger for heating ammonia to a suitable temperature and converting it into superheated ammonia gas. A secondary heat exchanger is provided between each of the secondary adiabatic reactors and at the end of the last secondary heat exchanger. Each of the secondary adiabatic reactors is also provided with an oxygen-containing gas inlet.

8. An adiabatic reaction system for the multi-stage selective hydrogen oxidation-promoted ammonia cracking hydrogen production method according to claims 1-6, characterized in that: The invention comprises an adiabatic reactor with multiple catalyst beds and a heat exchanger connected to the inlet of the adiabatic reactor for heating ammonia to a suitable temperature and converting it into superheated ammonia gas. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, and at least one catalyst bed in the rear section of the adiabatic reactor serves as the subsequent adiabatic catalytic reaction unit. An oxygen-containing gas inlet is arranged between the first adiabatic catalytic reaction unit and the subsequent adiabatic catalytic reaction unit of the adiabatic reactor.

9. An adiabatic reaction system for the multi-stage selective hydrogen oxidation-promoted ammonia cracking hydrogen production method according to claims 1-6, characterized in that: The invention comprises an adiabatic reactor having a plurality of catalyst beds arranged in sequence up and down, and a heat exchanger connected to the inlet end of the adiabatic reactor for heating ammonia to a suitable temperature and converting it into superheated ammonia gas. The first catalyst bed in the adiabatic reactor serves as the first adiabatic catalytic reaction unit, the rear catalyst bed in the adiabatic reactor serves as the subsequent adiabatic catalytic reaction unit, and oxygen-containing gas inlets are arranged between adjacent catalyst beds in the adiabatic reactor.

10. An adiabatic reaction system for the multi-stage selective hydrogen oxidation-promoted ammonia cracking hydrogen production method according to claims 1-6, characterized in that: At least one independent adiabatic reactor, an adiabatic reactor with multiple catalyst beds arranged in sequence up and down, and / or an adiabatic reactor with multiple catalyst beds are connected in series in sequence, the first adiabatic reactor serves as the first adiabatic catalytic reaction unit, and the remaining adiabatic reactors serve as subsequent adiabatic catalytic reaction units. The inlet end of the first adiabatic catalytic reaction unit is provided with a primary heat exchanger for heating ammonia to a suitable temperature to convert it into superheated ammonia gas, and the ends of the subsequent adiabatic catalytic reaction units are each provided with a secondary heat exchanger, and each of the subsequent adiabatic catalytic reaction units is also provided with an oxygen-containing gas inlet.

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