A molecular sieve for hydrogen production from ammonia decomposition and its preparation process

Abstract

This application relates to the field of molecular sieve technology, specifically disclosing a molecular sieve for ammonia decomposition to hydrogen production and its preparation process. The molecular sieve of this application is made from raw material particles after calcination. The raw material particles include the following components by weight: 70-80 parts of molecular sieve powder, 20-30 parts of clay, 3-5 parts of pore-forming agent, 8-12 parts of nickel nitrate, and 6-8 parts of binder; the clay includes attapulgite clay, the pore-forming agent includes rice husk powder, and the molecular sieve powder includes 5A molecular sieve powder, ZSM-5 molecular sieve powder, and MCM-41 mesoporous molecular sieve powder. The molecular sieve of this application exhibits high crushing resistance and strong static water adsorption capacity, and can be desorbed and regenerated at relatively low temperatures, fully overcoming the defects in related technologies and demonstrating ideal performance in ammonia decomposition to hydrogen production processes.

Description

Technical Field

[0001] This application relates to the field of molecular sieve technology, and more specifically, to a molecular sieve for hydrogen production from ammonia decomposition and its preparation process. Background Technology

[0002] The ammonia decomposition reaction refers to the chemical reaction in which ammonia gas decomposes under certain conditions. The chemical equation is 2NH3→3H2+N2-Q (where Q represents the heat absorbed). The hydrogen-nitrogen mixture obtained from ammonia decomposition is an excellent protective gas and can be widely used in the semiconductor industry, metallurgical industry, and other industries and scientific research requiring a protective atmosphere. It can also be used to produce pure hydrogen gas.

[0003] Ammonia molecules have a diameter of approximately 0.444 nm. Among commercially available molecular sieves, both 5A and 13X molecular sieves, based on pore size, can be used to adsorb ammonia molecules in a hydrogen-nitrogen mixture. 5A molecular sieves offer better economic efficiency and practicality. Currently, commercially available 5A molecular sieves have a crushing resistance of around 70 N and a static water adsorption capacity of around 21%. Desorption and regeneration require heating to above 300°C.

[0004] Regarding the aforementioned technologies, the inventors believe that the commercially available 5A molecular sieves have limited crush resistance, are prone to pulverization during use, have a short service life, and have poor adsorption effects on moisture and residual ammonia. They also require desorption and regeneration at high temperatures, resulting in less than ideal performance. Summary of the Invention

[0005] In related technologies, 5A molecular sieves are prone to pulverization and have poor adsorption effects on moisture and residual ammonia. They also require desorption and regeneration at high temperatures, resulting in less than ideal performance. To overcome these shortcomings, this application provides a molecular sieve for ammonia decomposition to produce hydrogen and its preparation process.

[0006] In a first aspect, this application provides a molecular sieve for hydrogen production from ammonia decomposition, employing the following technical solution:

[0007] A molecular sieve for hydrogen production by ammonia decomposition, wherein the molecular sieve is made from raw material particles after calcination, and the raw material particles comprise the following components in parts by weight: 70-80 parts of molecular sieve raw powder, 20-30 parts of clay, 3-5 parts of pore-forming agent, 8-12 parts of nickel nitrate, and 6-8 parts of binder; wherein the clay includes attapulgite clay, the pore-forming agent includes rice husk powder, and the molecular sieve raw powder includes 5A molecular sieve raw powder, ZSM-5 molecular sieve raw powder, and MCM-41 mesoporous molecular sieve raw powder.

[0008] By adopting the above technical solution, this application prepares a molecular sieve for ammonia decomposition to hydrogen production using three types of molecular sieve powders as the main raw materials. In the raw material system of this application, nickel nitrate decomposes into nickel oxide after calcination. Nickel oxide can work together with the calcined molecular sieve powder to catalytically degrade ammonia. Clay and binder can bind the components together, enabling them to form raw material particles with a certain strength. Rice husk powder in the raw material particles is converted into powdered rice husk ash after calcination. Rice husk ash is mainly composed of silicon dioxide and has high strength. Through synergistic cooperation with binder and clay, rice husk ash can provide good mechanical properties for the molecular sieve, helping to fully resist the working pressure in the ammonia decomposition to hydrogen production process and reducing the pulverization of the molecular sieve. Meanwhile, rice husk ash contains a large number of mesopores and macropores (i.e., mesopores and macropores as defined by IUPAC, the same below), while MCM-41 mesoporous molecular sieve powder can provide mesopores with a pore size of 2-3 nm, and 5A molecular sieve powder and ZSM-5 molecular sieve powder can provide micropores with a pore size of about 0.5 nm, thus forming a hierarchical structure of macropores, mesopores, and micropores. Among them, micropores and clay particles can adsorb small molecules such as water molecules and ammonia molecules, while macropores and mesopores can work together as diffusion channels, which is conducive to the passage of small molecules such as water molecules and ammonia molecules and reduces the obstacles encountered by small molecules such as water molecules and ammonia molecules during adsorption and desorption. This allows the molecular sieve to fully adsorb water molecules and ammonia molecules during operation, and desorption and regeneration are also easier. In summary, the molecular sieve of this application exhibits high crushing resistance and strong static water adsorption capacity, and can achieve good desorption and regeneration effects at relatively low temperatures, which helps to reduce energy consumption and achieve energy conservation and emission reduction. It fully overcomes the defects in related technologies and has a relatively ideal application effect in the ammonia decomposition hydrogen production process.

[0009] Preferably, the adhesive comprises sodium carboxymethyl cellulose and sodium silicate.

[0010] By adopting the above technical solution, this application preferably uses sodium carboxymethyl cellulose and sodium silicate as components as binders, which can improve the crushing resistance of molecular sieves and help reduce the pulverization of molecular sieves during use.

[0011] Preferably, the adhesive also includes glycerin.

[0012] By adopting the above technical solution, when the binder contains both sodium carboxymethyl cellulose and glycerol, the components in the raw material particles can be more fully bonded, thereby improving the crushing resistance of the molecular sieve and helping to reduce the pulverization of the molecular sieve during use.

[0013] Preferably, the adhesive also includes an inorganic sol.

[0014] By adopting the above technical solution, the inorganic sol can form a strong bond with the inorganic components such as clay and molecular sieve powder in the raw material particles after calcination, which can improve the crushing resistance of the molecular sieve and help reduce the pulverization of the molecular sieve during use.

[0015] Preferably, the inorganic sol is a silica sol or an aluminum sol, wherein the weight of the silica sol is based on the weight of silicon in the silica sol, and the weight of the aluminum sol is based on the weight of aluminum in the aluminum sol.

[0016] By adopting the above technical solution, this application further optimizes the type of inorganic sol, wherein aluminum sol has a good effect on improving the mechanical properties of molecular sieves and helps to improve the crushing resistance of catalysts.

[0017] Preferably, the clay further includes bentonite, which is sodium-based bentonite or calcium-based bentonite.

[0018] By adopting the above technical solution, this application selects bentonite as a clay component based on attapulgite. Bentonite has a better water absorption effect than attapulgite, which helps to improve the static water adsorption capacity of the molecular sieve. Among them, sodium-based bentonite has better water absorption performance, which helps to fully improve the static water adsorption capacity of the molecular sieve. As a preferred option, the molecular sieve has a crushing force ≥120N and a static water adsorption capacity ≥23%.

[0019] By adopting the above technical solution, the molecular sieve of this application has a crushing resistance of over 120N, while the crushing resistance of the national standard superior grade is 70N. Therefore, the molecular sieve of this application is not prone to pulverization during use, thus greatly extending its service life. Simultaneously, since the static water adsorption capacity of the molecular sieve of this application is higher than 23%, it is also superior to the commonly available 5A molecular sieves in terms of static water adsorption capacity.

[0020] Secondly, this application provides a process for preparing molecular sieves for hydrogen production from ammonia decomposition, using the following technical solution.

[0021] A process for preparing a molecular sieve for hydrogen production from ammonia decomposition includes the following steps:

[0022] (1) Dry the molecular sieve raw powder, pore-forming agent, nickel nitrate and clay separately and then mix them to obtain a mixed dry powder for later use; mix the binder and water to obtain a binder solution for later use;

[0023] (2) Mix the dry powder and a portion of the binder solution and add them to the rotary granulator. Start the rotary granulator to granulate and spray the remaining binder solution during the granulation process. After granulation, raw material granules are obtained.

[0024] (3) The raw material particles are dried and then roasted. After roasting, they are naturally cooled to obtain a molecular sieve for hydrogen production by ammonia decomposition.

[0025] By adopting the above technical solution, this application first prepares a mixed dry powder and a binder solution, and then mixes and granulates the mixed dry powder and binder solution to obtain raw material particles. After drying to fix the shape of the raw material particles, calcination is used to decompose nickel nitrate into nickel oxide, thereby obtaining a molecular sieve for ammonia decomposition to produce hydrogen.

[0026] Preferably, in step (3) of the preparation process, the dried raw material particles are roasted in two stages: a first roasting stage and a second roasting stage. The first roasting stage is carried out in an air atmosphere, and the second roasting stage is carried out in a hydrogen atmosphere.

[0027] By adopting the above technical solution, this application has selected a preferred calcination method. By calcining first in an air atmosphere and then in a hydrogen atmosphere, the nickel nitrate in the molecular sieve can be converted into nickel oxide and then reduced to elemental nickel, which helps to improve the catalytic decomposition effect of the molecular sieve on ammonia.

[0028] Preferably, the highest temperature in the first roasting stage is 500-600℃.

[0029] By adopting the above technical solution, this application has selected the highest temperature in the first calcination stage, which helps to improve the crushing resistance of the molecular sieve.

[0030] In summary, this application has the following beneficial effects:

[0031] 1. The molecular sieve of this application can exhibit high crushing resistance and strong static water adsorption capacity, and can be desorbed and regenerated at relatively low temperatures, which fully overcomes the defects in related technologies and has a more ideal application effect in the ammonia decomposition hydrogen production process.

[0032] 2. This application preferably uses sodium carboxymethyl cellulose, sodium silicate, glycerol, and inorganic sol as binders, which can significantly improve the crushing resistance of the molecular sieve and help reduce the pulverization of the molecular sieve during use.

[0033] 3. This application prefers a roasting method, which first roasts in an air atmosphere and then in a hydrogen atmosphere, so that the nickel nitrate in the molecular sieve can be converted into nickel oxide and then reduced to elemental nickel, which helps to improve the catalytic decomposition effect of the molecular sieve on ammonia. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0035] Example

[0036] Examples 1-5

[0037] The following description uses Example 1 as an example.

[0038] Example 1

[0039] This embodiment provides a molecular sieve for hydrogen production from ammonia decomposition, which is made from raw material particles after calcination. The raw material particles include the following components: 7 kg of molecular sieve raw powder, 2 kg of clay, 0.3 kg of pore-forming agent, 0.8 kg of nickel nitrate, and 0.6 kg of binder. The clay is attapulgite clay, the pore-forming agent is rice husk powder, and the molecular sieve raw powder is a mixture of 5A molecular sieve raw powder, ZSM-5 molecular sieve raw powder, and MCM-41 mesoporous molecular sieve raw powder in a weight ratio of 1:1.5:3.3. The binder is water glass with a modulus of 2.1 (the weight of water glass is based on sodium metasilicate, the same below) and sodium carboxymethyl cellulose (CAS:9004-32-4), and the weight ratio of water glass to sodium carboxymethyl cellulose is 1:1.

[0040] This embodiment provides a process for preparing molecular sieves for hydrogen production from ammonia decomposition, including the following steps:

[0041] (1) The molecular sieve raw powder, pore-forming agent, nickel nitrate and clay are dried at 105℃ and then mixed to obtain a mixed dry powder for later use; the binder and water are mixed to obtain a binder solution for later use; in this step, the amount of water used is 15% of the weight of the mixed dry powder.

[0042] (2) Mix the dry powder and half of the binder solution and add them to the rotary granulator. Start the rotary granulator and set the rotation speed to 26 r / min for granulation. Spray the remaining half of the binder solution during the granulation process. After granulation, raw material particles with an average particle size of 3.0 mm are obtained.

[0043] (3) The raw material particles are dried at 105℃ and then roasted. The roasting method is to preheat in an air atmosphere at 300℃ for 1 hour, then raise the temperature to 480℃ and roast for 2 hours. After the roasting is completed, the particles are naturally cooled to obtain a molecular sieve for hydrogen production by ammonia decomposition.

[0044] As shown in Table 1, the main difference between Examples 1-5 is that the raw material ratio of the raw material pellets is different.

[0045] Table 1 Raw material ratio of raw meal pellets

[0046] sample Example 1 Example 2 Example 3 Example 4 Example 5 Molecular sieve raw powder / kg 7 7.2 7.5 7.8 8 Clay / kg 2 2.2 2.5 2.8 3 Pore-forming agent / kg 0.3 0.35 0.4 0.45 0.5 Nickel nitrate / kg 0.8 0.9 1.0 1.1 1.2 Adhesive / kg 0.60 0.65 0.7 0.75 0.8

[0047] Example 6

[0048] The difference between this embodiment and Embodiment 5 is that the adhesive is composed of water glass, sodium carboxymethyl cellulose and glycerin in a weight ratio of 1:1:0.2.

[0049] Example 7

[0050] The difference between this embodiment and Embodiment 6 is that the binder is composed of water glass, sodium carboxymethyl cellulose, glycerol and inorganic sol in a weight ratio of 1:1:0.2:0.5. The inorganic sol is selected as silica sol with a solid content of 15% (the weight of silica sol is based on the weight of silicon element in silica sol, the same below).

[0051] Example 8

[0052] The difference between this embodiment and Embodiment 7 is that the inorganic sol used is an aluminum sol with a solid content of 15% (the weight of the aluminum sol is based on the weight of the aluminum element in the aluminum sol, the same below).

[0053] Example 9

[0054] The difference between this embodiment and embodiment 8 is that the clay is a mixture of attapulgite and bentonite in a weight ratio of 2:1, and the bentonite is calcium-based bentonite.

[0055] Example 10

[0056] The difference between this embodiment and Embodiment 9 is that the bentonite is sodium-based bentonite.

[0057] Example 11

[0058] The difference between this embodiment and Embodiment 10 is that step (3) of the preparation process involves calcining the dried raw material particles in two stages: a first calcination stage and a second calcination stage. The first calcination stage is carried out in an air atmosphere, while the second calcination stage is carried out in a hydrogen atmosphere. In the first calcination stage, the material is preheated in an air atmosphere at 300°C for 1 hour, then heated to 480°C and held at that temperature for 2 hours before proceeding to the second calcination stage. In the second calcination stage, the temperature is maintained, argon gas is first introduced to purge the air, and then hydrogen gas is introduced at a rate of 25 mL / min for reduction. The calcination is completed after 1 hour.

[0059] As shown in Table 2, the difference between Examples 11-15 is that after preheating in the first stage, the temperature is raised to different temperatures (referred to as roasting temperature / °C) for roasting.

[0060] Table 2 Calcination Temperature

[0061] sample Calcination temperature / °C Example 11 480 Example 12 500 Example 13 550 Example 14 600 Example 15 630

[0062] Example 16

[0063] The difference between this embodiment and Embodiment 1 is that sodium silicate is completely replaced with sodium carboxymethyl cellulose.

[0064] Example 17

[0065] The difference between this embodiment and Embodiment 1 is that sodium carboxymethyl cellulose is completely replaced with sodium silicate.

[0066] Comparative Example

[0067] Comparative Example 1

[0068] This comparative example provides a molecular sieve for hydrogen production from ammonia decomposition, which is made from raw material particles after calcination. The raw material particles include the following components: 9.3 kg of molecular sieve raw powder, 0.8 kg of nickel nitrate, and 0.4 kg of binder. The molecular sieve raw powder is a mixture of 5A molecular sieve raw powder and ZSM-5 molecular sieve raw powder in a weight ratio of 1:1.5. The binder is selected from water glass and sodium carboxymethyl cellulose, and the weight ratio of water glass and sodium carboxymethyl cellulose is 1:1.

[0069] This comparative example provides a process for preparing molecular sieves for hydrogen production from ammonia decomposition, including the following steps:

[0070] (1) The molecular sieve raw powder and nickel nitrate are dried at 105°C and then mixed to obtain a mixed dry powder for later use; the binder and water are mixed to obtain a binder solution for later use; in this step, the amount of water used is 15% of the weight of the mixed dry powder.

[0071] (2) Mix the dry powder and half of the binder solution and add them to the rotary granulator. Start the rotary granulator and set the rotation speed to 26 r / min for granulation. Spray the remaining half of the binder solution during the granulation process. After granulation, raw material particles with an average particle size of 3.0 mm are obtained.

[0072] (3) The raw material particles are dried at 105℃ and then roasted. The roasting method is to preheat in an air atmosphere at 300℃ for 1 hour, then raise the temperature to 480℃ and roast for 2 hours. After the roasting is completed, the particles are naturally cooled to obtain a molecular sieve for hydrogen production by ammonia decomposition.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that, based on Example 1, the clay in the raw material pellet formulation is replaced with molecular sieve powder (the three types of molecular sieve powder are still compounded according to the proportions of Example 1).

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that, based on Example 1, the pore-forming agent in the raw material pellet formulation is replaced with molecular sieve powder (the three types of molecular sieve powder are still compounded according to the proportions of Example 1).

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that, based on Example 1, the MCM-41 mesoporous molecular sieve powder is replaced with a mixture of 5A molecular sieve powder and ZSM-5 molecular sieve powder (mixed at a weight ratio of 1:1.5).

[0079] Performance testing methods

[0080] I. Crushing resistance

[0081] The test shall be conducted in accordance with the provisions of "HG / T 2783-2020 Test Method for Crushing Resistance of Molecular Sieves".

[0082] II. Static water adsorption capacity

[0083] The procedure was performed in accordance with the provisions of GB / T 6287-2021, "Determination of Static Water Adsorption by Molecular Sieves".

[0084] III. Desorption effect

[0085] The sample was placed in a muffle furnace and dried at 200℃ for 6 hours to remove adsorbed moisture and other impurity gases. The dried sample was then placed in a sealed container filled with a saturated magnesium nitrate solution. This sealed container was incubated at 30℃ and 50℃ for 6 hours each. Thermal analysis was then performed on the sample, with a heating range of 30-500℃ and a heating rate of 10℃ / min. The weight loss W of the molecular sieve at 200℃ was measured. 200 Total weight loss of the sample W T Calculate W 200 and W T The ratio of the two values ​​is the desorption efficiency.

[0086] The ratio between the desorption efficiency of each embodiment and the desorption efficiency of Comparative Example 1 was calculated and recorded as the relative desorption efficiency. The results are shown in Table 3.

[0087] IV. Catalytic Decomposition Effect

[0088] Using the molecular sieves of Examples 10 and 11-15 as the test objects, the ammonia decomposition performance of the molecular sieves was evaluated in a fixed-bed reactor under normal pressure. 0.1 g of molecular sieve was weighed and added to the fixed-bed reactor, and the reactor was purged with ammonia gas at 300℃ for 30 min. Then, the ammonia decomposition hydrogen production performance was evaluated at 650℃. The content of each component was analyzed online by gas chromatography (GC4000A), and the ammonia decomposition conversion rate was calculated. The results are shown in Table 4.

[0089] Table 3 Performance Testing

[0090]

[0091]

[0092] Table 4 Ammonia decomposition conversion rate

[0093] sample Ammonia decomposition conversion rate / % Example 10 72.6 Example 11 74.7 Example 12 74.8 Example 13 75.1 Example 14 75.0 Example 15 75.1

[0094] As can be seen from Examples 1-5 and Comparative Example 1, and Table 3, the crushing resistance, static water adsorption capacity, and relative desorption efficiency measured in Examples 1-5 are significantly higher than those in Comparative Example 1. This is because the combination of rice husk ash, binder, clay, and other components provides good mechanical properties for the molecular sieve. Moreover, the hierarchical structure of macropores, mesopores, and micropores reduces the obstacles encountered by small molecules such as water molecules and ammonia molecules during adsorption and desorption, enabling the molecular sieve to fully adsorb water molecules and ammonia molecules during operation, and making desorption and regeneration easier.

[0095] Combining Example 1 and Comparative Example 2 with Table 3, it can be seen that Comparative Example 2 has low static water adsorption capacity and crushing resistance. This indicates that in the absence of clay, it is difficult for the molecular sieve to have high strength by relying solely on the binder. Moreover, due to the lack of clay, the water absorption performance of the molecular sieve is relatively poor.

[0096] Based on Example 1 and Comparative Examples 3-4, and in conjunction with Table 3, it can be seen that when the pore-forming agent or MCM-41 mesoporous molecular sieve powder is lacking, the static water adsorption capacity and relative desorption efficiency of the molecular sieve are both low, indicating that the macropores, mesopores, and micropores in the molecular sieve have not formed an ideal hierarchical structure.

[0097] Combining Examples 5 and 6 with Table 3, it can be seen that the crushing resistance measured in Example 6 is greater than that in Example 5. This indicates that when the binder contains both sodium carboxymethyl cellulose and glycerol, the components in the raw material particles can be more fully bonded, thereby improving the crushing resistance of the molecular sieve and helping to reduce the pulverization of the molecular sieve during use.

[0098] Combining Examples 6 and 7-8 with Table 3, it can be seen that the crushing resistance measured in Examples 7-8 is greater than that in Example 6, indicating that the addition of inorganic sol can further improve the crushing resistance of the molecular sieve and help reduce pulverization during use. The crushing resistance measured in Example 8 is greater than that in Example 7, indicating that aluminum sol is more helpful in improving the crushing resistance of the molecular sieve than silica sol.

[0099] Combining Examples 8 and 9-10 with Table 3, it can be seen that the static water adsorption capacity measured in Examples 9-10 is greater than that in Example 8, indicating that replacing part of the attapulgite with bentonite helps to improve the static water adsorption capacity of the molecular sieve. The static water adsorption capacity measured in Example 10 is greater than that in Example 9. This is because sodium-based bentonite has better water absorption properties, which helps to fully improve the static water adsorption capacity of the molecular sieve.

[0100] Combining Examples 10 and 11-15 with Table 4, it can be seen that the ammonia decomposition conversion rates measured in Examples 11-15 are all higher than those in Example 10, indicating that hydrogen roasting after air roasting helps improve the catalytic decomposition effect of the molecular sieve on ammonia. Furthermore, as shown in Table 3, among Examples 11-15, Examples 12-14 exhibit higher crushing resistance, while the crushing resistance of Example 15 shows a decrease, indicating that setting the maximum temperature of the first roasting stage at 500-600℃ is more appropriate.

[0101] As can be seen from Examples 1 and 16-17 and Table 3, when sodium carboxymethyl cellulose and water glass are not used together, the crushing resistance of the molecular sieve is relatively low.

[0102] The above embodiments are merely explanations of this application and are not intended to limit it. After reading this specification, those skilled in the art can make modifications to the embodiments of this application without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of this application.

Claims

1. A molecular sieve for hydrogen production from ammonia decomposition, characterized in that, The molecular sieve is made from raw material particles after calcination. The raw material particles include the following components in parts by weight: 70-80 parts of molecular sieve raw powder, 20-30 parts of clay, 3-5 parts of pore-forming agent, 8-12 parts of nickel nitrate, and 6-8 parts of binder. The clay includes attapulgite clay, the pore-forming agent includes rice husk powder, and the molecular sieve raw powder includes 5A molecular sieve raw powder, ZSM-5 molecular sieve raw powder, and MCM-41 mesoporous molecular sieve raw powder. The method for preparing the molecular sieve for hydrogen production from ammonia decomposition includes the following steps: (1) Dry the molecular sieve raw powder, pore-forming agent, nickel nitrate and clay separately and then mix them to obtain a mixed dry powder for later use; mix the binder and water to obtain a binder solution for later use; (2) Mix the dry powder and a portion of the binder solution and add them to the rotary granulator. Start the rotary granulator to granulate and spray the remaining binder solution during the granulation process. After granulation, raw material granules are obtained. (3) The raw material particles are dried and then roasted. After roasting, they are naturally cooled to obtain a molecular sieve for hydrogen production by ammonia decomposition.

2. The molecular sieve for hydrogen production from ammonia decomposition according to claim 1, characterized in that, The adhesive comprises sodium carboxymethyl cellulose and sodium silicate.

3. The molecular sieve for hydrogen production from ammonia decomposition according to claim 2, characterized in that, The adhesive also includes glycerin.

4. The molecular sieve for hydrogen production from ammonia decomposition according to claim 2, characterized in that, The adhesive also includes inorganic sol.

5. The molecular sieve for hydrogen production from ammonia decomposition according to claim 4, characterized in that, The inorganic sol is a silica sol or an aluminum sol, the weight of which is based on the weight of silicon in the silica sol and the weight of which is based on the weight of aluminum in the aluminum sol.

6. The molecular sieve for hydrogen production from ammonia decomposition according to claim 1, characterized in that, The clay also includes bentonite; the bentonite is sodium-based bentonite or calcium-based bentonite.

7. The molecular sieve for hydrogen production from ammonia decomposition according to claim 1, characterized in that, The molecular sieve has a crushing resistance of ≥120N and a static water adsorption capacity of ≥23%.

8. The preparation process of molecular sieves for hydrogen production from ammonia decomposition according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Dry the molecular sieve raw powder, pore-forming agent, nickel nitrate and clay separately and then mix them to obtain a mixed dry powder for later use; mix the binder and water to obtain a binder solution for later use; (2) Mix the dry powder and a portion of the binder solution and add them to the rotary granulator. Start the rotary granulator to granulate and spray the remaining binder solution during the granulation process. After granulation, raw material granules are obtained. (3) The raw material particles are dried and then roasted. After roasting, they are naturally cooled to obtain a molecular sieve for hydrogen production by ammonia decomposition.

9. The preparation process of molecular sieve for hydrogen production from ammonia decomposition according to claim 8, characterized in that, In step (3) of the preparation process, the dried raw material particles are roasted in two stages: a first roasting stage and a second roasting stage. The first roasting stage is carried out in an air atmosphere, and the second roasting stage is carried out in a hydrogen atmosphere.

10. The preparation process of molecular sieve for hydrogen production from ammonia decomposition according to claim 9, characterized in that, The highest temperature in the first roasting stage is 500-600℃.

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