Preparation method of hydrogen production catalyst and application thereof

Abstract

The application relates to a preparation method of a hydrogen production catalyst and application thereof, and belongs to the technical field of catalysts. The preparation method comprises the following steps: 1) weighing gamma-Al2O3, calcium aluminate cement and calcium carbonate, adding a binder and a pore-forming agent, ball-milling and mixing, adding deionized water, and then performing compression molding; under the atmosphere of nitrogen and water vapor, roasting is carried out; immediately after being hot, quenching is carried out by immersing in deionized water; cooling is carried out; roasting is carried out again in the nitrogen atmosphere, and a carrier is obtained; 2) the carrier is immersed in a nickel nitrate solution twice through ultrasonic immersion, and is filtered and dried; roasting and decomposition are carried out in an air atmosphere, and the hydrogen production catalyst is obtained. The hydrogen production catalyst obtained through the preparation method has high activity, high stability and strong carbon deposition resistance, and can be applied to the hydrogen production in a hydrocarbon steam conversion reaction.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a hydrogen production catalyst and application thereof, and belongs to the technical field of catalysts. BACKGROUND

[0002] Hydrogen is widely used and highly efficient and environmentally friendly, and is increasingly widely concerned as a carrier connecting different forms of energy. The hydrocarbon steam reforming method has the advantages of low investment, mature and reliable process, flexible and convenient operation and low cost, and is the most widely used hydrogen production method in industry.

[0003] The core part of the hydrocarbon steam reforming method is the reforming reaction, and the reforming catalyst is the key to the reforming reaction. The commonly used reforming catalyst is mainly a relatively low-cost and excellent-activity nickel-based catalyst. The nickel-based catalyst mainly includes a pre-sintered type and a potassium-containing type. The pre-sintered catalyst is generally prepared by using high-temperature pre-sintered alumina as a carrier and then impregnating an active component nickel. The specific surface area of the catalyst is low, and the carbon deposition resistance is poor. The traditional way to solve the carbon deposition problem is to mix potassium feldspar with the active component and then form a potassium-containing catalyst, so as to use alkali to achieve the carbon deposition resistance. However, the addition of potassium alkali reduces the activity of the catalyst, and the potassium alkali is easy to be lost during the reaction, resulting in poor stability of the catalyst.

[0004] Chinese patent CN113198544A discloses a honeycomb catalyst for treating tail gas and other industrial waste gas. The catalyst is prepared by mixing, dispersing and aging the active component after high-temperature melting and rapid cooling of the carrier. The patent does not generate the key card detritus component, and only involves low shrinkage and uniform pore size of the catalyst, but cannot achieve the carbon deposition resistance effect.

[0005] Chinese patent CN107321354B discloses a high-temperature and high-selectivity carbon dioxide methanation catalyst and a preparation method thereof. The catalyst is prepared by improving the traditional impregnation method. First, a magnesium-aluminum spinel carrier is prepared by a hydrothermal synthesis method, and then a nickel nitrate salt is used as an impregnation liquid to uniformly load the nickel-containing component on the carrier. Finally, the impregnated catalyst precursor is subjected to acid washing treatment, so that the nickel oxide is distributed in the "egg yolk type" on the carrier. Hydrogen is small in molecule and large in diffusion coefficient, which is more conducive to diffusion into the catalyst, thereby improving the hydrogen-carbon ratio in the catalyst, and the improvement of the hydrogen-carbon ratio can obviously improve the selectivity of the catalyst, but cannot obviously improve the carbon deposition resistance effect of the catalyst.

[0006] The document "Concerning Multiple Properties and Quenching of Tricalcium Aluminate" introduces the change in the form of tricalcium aluminate in cement after high-temperature quenching treatment, but does not involve the application in the catalyst field and the carbon deposition resistance effect.

[0007] Traditional hydrocarbon steam reforming catalysts for hydrogen production suffer from a series of problems, including low specific surface area, easy loss of potassium alkali, poor resistance to coking, and poor stability. With the continuous expansion of the range of hydrogen feedstocks in recent years, higher requirements have been placed on the activity, stability, and other properties of hydrocarbon steam reforming catalysts, especially their resistance to coking.

[0008] Overcoming the shortcomings of existing nickel-based catalysts and producing catalysts with high activity, high stability, and strong resistance to coking is the key research and development focus of hydrocarbon steam reforming hydrogen production catalysts. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a hydrogen production catalyst and its application, wherein the catalyst has high activity, high stability and strong resistance to carbon deposition.

[0010] A method for preparing a hydrogen production catalyst includes the following steps:

[0011] 1) Weigh γ-Al2O3, calcium aluminate cement and calcium carbonate and mix them. Then add binder and pore-forming agent, ball mill and mix thoroughly. After adding deionized water, press and mold. Under the atmosphere of nitrogen and water vapor, perform the first calcination to obtain the crude carrier product a. Immediately immerse the calcined crude carrier product a in deionized water while hot and quench it. After cooling, obtain the crude carrier product b. Calcin the crude carrier product b again in the atmosphere of nitrogen to obtain the carrier.

[0012] 2) The support is placed in a nickel nitrate solution, ultrasonically impregnated for the first time, filtered, and dried; then it is placed in a nickel nitrate solution again for a second ultrasonic impregnation, filtered, and calcined in air to decompose, thus obtaining the hydrogen production catalyst.

[0013] In step 1), the volume ratio of nitrogen to water vapor is 1:0.4~0.6.

[0014] Step 1) The specific operation of the initial roasting is: roasting at 1300℃~1550℃ for 4~8 hours.

[0015] Step 1) The specific operation of the second roasting is: roasting at 1000℃~1350℃ for 10min~30min.

[0016] The specific operation of quenching by immersion in deionized water in step 1) is as follows: immerse in deionized water at 15℃~150℃ for quenching for 10min~30min.

[0017] In step 1), the mass ratio of γ-Al2O3, calcium aluminate cement, and calcium carbonate is 1:1.2~1.3:0.2~0.3.

[0018] Step 1) The mass ratio of γ-Al2O3, binder and pore-forming agent is 100:3~6:2-4.

[0019] Step 1) The binder is one or more of graphite, paraffin wax, and stearic acid; the pore-forming agent is one or more of guar gum powder, nitrate, and carbonate.

[0020] In the hydrogen production catalyst described in step 2), the active component, calculated as nickel oxide (hereinafter referred to as nickel oxide), is 10-18 wt%. Preferably, in the hydrogen production catalyst described in step 2), the active component, calculated as nickel oxide, is 10.2-17.8 wt%. More preferably, in the hydrogen production catalyst described in step 2), the active component, calculated as nickel oxide, is 16.7 wt%. In this invention, the mass percentage of the active component is the same as the mass percentage of nickel oxide.

[0021] The hydrogen production catalyst prepared by this method is used in the production of hydrogen through hydrocarbon steam reforming. Specifically, the hydrogen production catalyst can be reduced to the active component nickel at 800℃~1000℃ under a hydrogen atmosphere, and is suitable for steam reforming reactions using light hydrocarbons, oilfield gas, or natural gas as feedstocks to produce product hydrogen.

[0022] In industrial settings, the steam reforming reaction is carried out under the following conditions: furnace inlet temperature 400°C–600°C, outlet temperature 700–850°C, and carbon space velocity 600 h⁻¹. -1 -1000h -1 The water-to-carbon ratio is 2.0~4.5, and the pressure is 2.0~4.0 MPa.

[0023] The calcium aluminate cement mentioned in step 1) is pure calcium aluminate cement, with an Al2O3 content of 50:50 CaO content.

[0024] The frequency of the ultrasound in step 2) is 20kHz-60kHz.

[0025] Step 2) The roasting in the air atmosphere is roasting in a muffle furnace.

[0026] The ball milling time in step 1) is 2-4 hours.

[0027] Step 1) The shape of the carrier includes Raschig ring, four-hole cylindrical, seven-hole cylindrical, seven-ribbed wheel-shaped, and other porous spherical or cylindrical shapes.

[0028] The specific drying operation described in step 2) is as follows: dry at 120℃~180℃ for 8h~24h.

[0029] The first ultrasonic immersion in step 2) has an immersion time of 30 min to 60 min; the second ultrasonic immersion in step 2) has an immersion time of 30 min to 60 min.

[0030] The frequency of the ultrasound in step 2) is 20kHz-60kHz.

[0031] Step 2) The concentration of the nickel nitrate solution is 100~400g / L, preferably 200g / L.

[0032] The specific operation of roasting and decomposition in step 2) is: roasting and decomposition at 350℃~550℃ for 2h~8h.

[0033] Step 2) The muffle furnace mentioned refers to the furnace used for baking in an air atmosphere.

[0034] The hydrogen production catalyst can be prepared by the above method. The obtained hydrogen production catalyst comprises the following components in the following mass percentages: active component (calculated as nickel oxide) 10-18 wt%, carbide 5-15 wt%, α-Al₂O₃ 30-40 wt%, CaO 5-15 wt%, and the balance being calcium aluminate.

[0035] The hydrogen production catalyst has a pore volume of 0.172~0.278 cm³. 3 / g, specific surface area 58.79~86.9m² 2 / g, lateral compressive strength 321~407N / particle, bulk density 0.80~1.20kg / L.

[0036] The applicant discovered in their research that the water-to-carbon ratio is a crucial and sensitive process parameter in hydrocarbon steam reforming reactions. Increasing the water-to-carbon ratio can significantly reduce catalyst coking, because water vapor can react with the coke deposits formed on the catalyst as follows:

[0037] C + H₂O = CO + H₂

[0038] The active oxygen in the steam oxidizes the carbon deposited during the conversion process into gaseous CO. However, an excessively high water-to-carbon ratio increases energy consumption and causes a greater pressure difference between the inlet and outlet of the converter, which increases the growth rate of nickel grains and is detrimental to the stability of the reaction system.

[0039] Katoite, also known as non-silica hydrochloride, has the general chemical formula Ca3Al2(O4H4)3. It can be obtained from the final hydrated stable phase of calcium aluminate, etc., and contains a considerable amount of OH. - , and OH - It also contains a large amount of active oxygen, which can provide oxygen to the active metal components in the catalyst. Furthermore, carbosite decomposes to produce H₂O.

[0040] Ca3Al2(O4H4)3=3Ca(OH)2+Al2O3+3H2O

[0041] Carbohydrate contains a large amount of OH - The generation of H2O increases the water-to-carbon ratio, and the high content of active oxygen can re-oxidize the C deposited on the catalyst into CO and CO2, thereby improving the catalyst's resistance to carbon deposition, thus improving the catalyst's stability and extending its lifespan.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. The preparation method of the hydrogen production catalyst of the present invention, wherein the design of calcination-quenching-calcination during preparation causes the support to generate a catalyst containing a large amount of OH. - The active oxygen-containing carbide component helps to inhibit catalyst coking and can oxidize the existing coke deposits on the catalyst into CO and CO2, thereby enhancing the catalyst's anti-coking performance, improving its stability and lifespan, and making it more adaptable to a wider range of hydrogen production feedstocks and better suited for application in hydrocarbon steam reforming hydrogen production.

[0044] 2. The preparation method of the hydrogen production catalyst of the present invention utilizes the huge temperature difference and rapid temperature change between calcination and quenching. The calcination-quenching-calcination process in step 1) is the key step in generating the carbosite component. This causes the deionized water in the catalyst pores to undergo a phase change and vaporize into water vapor. The water vapor expands rapidly in the pores, which greatly increases the number of mesoporous structures in the catalyst, improves the specific surface area of ​​the catalyst, and thus improves the dispersion of the active component nickel.

[0045] 3. The preparation method of the hydrogen production catalyst of the present invention allows for controllable composition, structure, and support amount of the resulting hydrogen production catalyst. Compared with hydrogen production catalysts prepared by the traditional impregnation method, the hydrogen production catalyst prepared by the present invention does not require the addition of additional anti-carbon potassium alkali additives, has no effect of potassium alkali on catalyst activity, and eliminates the risk of potassium alkali loss affecting downstream processes. Attached Figure Description

[0046] Figure 1 This is the X-ray diffraction (XRD) pattern of the catalyst described in this invention.

[0047] Figure 2 This is a schematic diagram of the process of a miniature atmospheric pressure evaluation device in performance testing.

[0048] The components include: 1. Hydrogen cylinder; 101. First mass flow meter; 2. Methane cylinder; 201. Second mass flow meter; 3. Water tank; 301. Water pump; 4. Mixer; 5. Preheater; 6. Reactor; 7. Cooler; 8. Gas-liquid separator; 801. Tail gas vent pipe; 802. Drain pipe; 9. Chromatograph. Detailed Implementation

[0049] The present invention will be further described below with reference to specific embodiments, wherein Embodiment 1 is the preferred embodiment. The comparative example is designed by the applicant to compare the effects of the embodiments, and the specific design is as follows.

[0050] γ-Al2O3 was purchased from Wenzhou Jingjing Alumina Co., Ltd., Zhejiang Province, model Q / WYL01-2001;

[0051] The calcium aluminate cement was purchased from Shandong Refractory Materials Co., Ltd. It is No. 75 cement with an Al2O3:CaO content of 50:50.

[0052] Nickel nitrate solution is an aqueous solution of nickel nitrate, and water is the solvent.

[0053] The industrial catalyst used in Comparative Example 10 (designated D-CAT-10) was purchased from Chengdu Shengli Technology Co., Ltd., model Z118Y, with an active component (calculated as nickel oxide) content of 19%.

[0054] The ultrasonic impregnation equipment was purchased from Kunshan Ultrasonic Instrument Co., Ltd., model KQ2200, with an ultrasonic input power of 100W and a frequency of 20kHz-60kHz.

[0055] Step 1) The equipment used for the two roasting processes is from Luoyang Juxing Co., Ltd., model GWL-1200XAD;

[0056] The muffle furnace roasting used in the examples and comparative examples refers to roasting in an air atmosphere.

[0057] To minimize variations, the carriers used in both the examples and comparative examples were press-molded into a four-hole cylindrical shape, with a diameter of 1.1 cm and a height of 1.6 cm.

[0058] Example 1

[0059] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0060] 1) Weigh 100g γ-Al2O3, 125g high-temperature pre-calcined calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a in deionized water at 30℃ for quenching for 20min until completely cooled; calcine the cooled carrier again at 1100℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0061] 2) The support was immersed in 200 mL of a 200 g / L nickel nitrate solution and ultrasonically soaked for 40 min. After filtration, it was dried in an oven at 150 °C for 12 h. Then, it was immersed in the nickel nitrate solution again and ultrasonically soaked for 40 min, filtered, and calcined in a muffle furnace at 450 °C for 6 h to obtain the hydrogen production catalyst, designated CAT-1. The nickel oxide content in the hydrogen production catalyst was 16.7 wt%.

[0062] Example 2

[0063] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0064] 1) Weigh 100g γ-Al2O3, 120g high-temperature pre-fired calcium aluminate cement, and 20g calcium carbonate and mix them. Then add 3g graphite and 2g guar gum powder. Ball mill for 2 hours to fully mix the components. After adding deionized water, press and mold the mixture. The subsequent steps are the same as in Example 1.

[0065] 2) Step 2 is the same as in Example 1, obtaining a hydrogen production catalyst, designated CAT-2. The hydrogen production catalyst contains 15.1 wt% nickel oxide.

[0066] Example 3

[0067] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0068] 1) Weigh 100g γ-Al2O3, 130g high-temperature pre-fired calcium aluminate cement, and 30g calcium carbonate and mix them together. Then add 6g graphite and 4g guar gum powder. Ball mill for 4 hours to fully mix the components. After adding deionized water, press and mold the mixture. The subsequent steps are the same as in Example 1.

[0069] 2) Step 2 is the same as in Example 1, obtaining a hydrogen production catalyst, designated CAT-3. The hydrogen production catalyst contains 17.8 wt% nickel oxide.

[0070] Example 4

[0071] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0072] 1) Weigh 100g γ-Al2O3, 125g high-temperature pre-calcined calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1300℃ for 4h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.4; immediately immerse the calcined carrier completely in deionized water at 30℃ for 20min until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1000℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0073] 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, designated CAT-4. The hydrogen production catalyst contains 11.3 wt% nickel oxide.

[0074] Example 5

[0075] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0076] 1) Weigh 100g γ-Al2O3, 125g high-temperature pre-calcined calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1550℃ for 4h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.6 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1350℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0077] 2) Step 2) is the same as in Example 1, to obtain a hydrogen production catalyst, designated CAT-5. The hydrogen production catalyst contains 14.3 wt% nickel oxide.

[0078] Example 6

[0079] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0080] 1) Weigh 100g γ-Al2O3, 125g high-temperature pre-calcined calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 15℃ while hot and quench for 30min until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1100℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0081] 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, designated CAT-6. The hydrogen production catalyst contains 13.9 wt% nickel oxide.

[0082] Example 7

[0083] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0084] 1) Weigh 100g γ-Al2O3, 125g high-temperature pre-calcined calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; while still hot, immediately immerse crude carrier a completely in deionized water at 150℃ and quench for 10min until completely cooled to obtain crude carrier b; calcine crude carrier b again in a nitrogen atmosphere at 1100℃ for 20min to obtain the carrier.

[0085] 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, designated CAT-7. The hydrogen production catalyst contains 10.2 wt% nickel oxide.

[0086] Example 8

[0087] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0088] 1) The carrier preparation steps are the same as in Example 1;

[0089] 2) The support was immersed in 200 mL of a 200 g / L nickel nitrate solution for 30 min under ultrasonic conditions, filtered, and dried in an oven at 120 °C for 8 h. It was then immersed again in the nickel nitrate solution for 30 min under ultrasonic conditions, filtered, and calcined in a muffle furnace at 350 °C for 2 h to obtain the hydrogen production catalyst, designated CAT-8. The nickel oxide content in the hydrogen production catalyst was 14.2 wt%.

[0090] Example 9

[0091] The preparation method of the hydrogen production catalyst in this embodiment includes the following steps:

[0092] 1) The carrier preparation steps are the same as in Example 1;

[0093] 2) The support was immersed in 200 mL of a 200 g / L nickel nitrate solution for 60 min under ultrasonic conditions, filtered, and dried in an oven at 180 °C for 24 h. It was then immersed again in the nickel nitrate solution for 60 min under ultrasonic conditions, filtered, and calcined in a muffle furnace at 550 °C for 8 h to obtain the hydrogen production catalyst, designated CAT-9. The nickel oxide content in the hydrogen production catalyst was 17.3 wt%.

[0094] Comparative Example 1

[0095] In this comparative example, step 1) involves initial roasting, but no quenching or re-roasting;

[0096] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0097] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h under an atmosphere of nitrogen and water vapor mixed in a volume ratio of N2:H2O=1:0.5 to obtain the carrier;

[0098] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-1.

[0099] Comparative Example 2

[0100] In step 1) of this comparative example, there is an initial roasting and quenching, but after quenching, there is no second roasting;

[0101] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0102] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h under an atmosphere of nitrogen and water vapor mixed in a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; while still hot, immediately immerse crude carrier a completely in deionized water at 30℃ and quench for 20min until all carriers are completely cooled, then place it in an oven and dry at 120℃ for 12h to obtain the carrier;

[0103] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-2.

[0104] Comparative Example 3

[0105] This comparative example varied the roasting atmosphere;

[0106] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0107] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate and mix them together. Then add 5g graphite and 3g guar gum powder. Ball mill for 3 hours to ensure that all components are fully mixed. After adding deionized water, press the mixture into shape and calcine it in a muffle furnace at 1450℃ for 6 hours to obtain crude carrier product a. Immediately immerse the calcined crude carrier product a in deionized water at 30℃ while it is still hot and quench it for 20 minutes until it is completely cooled to obtain crude carrier product b. Calcin the cooled crude carrier product b again in a nitrogen atmosphere at 1100℃ for 20 minutes to obtain the carrier.

[0108] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-3.

[0109] Comparative Example 4

[0110] This comparative example did not use ultrasonic impregnation.

[0111] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0112] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1100℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0113] 2) The support was immersed in 200 mL of 200 g / L nickel nitrate solution for 40 min, filtered dry, and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again for 40 min, filtered dry, and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-4.

[0114] Comparative Example 5

[0115] In this comparative example, step 1) was too low in the roasting temperature;

[0116] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0117] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 800℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 800℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0118] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-5.

[0119] Comparative Example 6

[0120] Step 2) of this comparative example uses only a single ultrasonic immersion.

[0121] The preparation method of this comparative hydrogen production catalyst includes the following steps:

[0122] 1) Weigh 100g γ-Al2O3, 125g calcium aluminate cement, and 25g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1100℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0123] 2) The support was immersed in 200 mL of 200 g / L nickel nitrate solution under ultrasonic conditions for 40 min, filtered dry, and then calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-6.

[0124] Comparative Example 7

[0125] This comparative example changed the carrier component in step 1);

[0126] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0127] 1) Weigh 100g of γ-Al2O 3、 Calcium carbonate, after being mixed with deionized water and pressed into shape, was calcined at 1450℃ for 6 hours in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier product a; the calcined crude carrier product a was immediately and completely immersed in deionized water at 30℃ for 20 minutes until it was completely cooled to obtain crude carrier product b; the cooled crude carrier product b was calcined again at 1100℃ for 20 minutes in a nitrogen atmosphere to obtain the carrier.

[0128] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-7.

[0129] Comparative Example 8

[0130] This comparative example changed the component ratio in step 1), reducing the proportion of calcium aluminate cement and calcium carbonate.

[0131] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0132] 1) Weigh 100g γ-Al2O3, 50g calcium aluminate cement, and 5g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1100℃ for 20min in a nitrogen atmosphere to obtain the carrier.

[0133] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-8.

[0134] Comparative Example 9

[0135] This comparative example changed the component ratio in step 1), increasing the proportion of calcium aluminate cement and calcium carbonate.

[0136] The preparation method of the hydrogen production catalyst in this comparative example includes the following steps:

[0137] 1) Weigh 100g γ-Al2O3, 200g calcium aluminate cement, and 50g calcium carbonate, mix them, then add 5g graphite and 3g guar gum powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, calcine at 1450℃ for 6h under an atmosphere of nitrogen and water vapor with a volume ratio of N2:H2O=1:0.5 to obtain crude carrier a; immediately immerse the calcined crude carrier a completely in deionized water at 30℃ for 20min while hot and quench until completely cooled to obtain crude carrier b; calcine the cooled crude carrier b again at 1100℃ for 20min under a nitrogen atmosphere to obtain the carrier.

[0138] 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered dry and dried in an oven at 150 °C for 12 h. Then it was immersed in nickel nitrate solution again under ultrasonic conditions for 40 min, filtered dry and calcined in a muffle furnace at 450 °C for 6 h to obtain hydrogen production catalyst D-CAT-9.

[0139] Comparative Example 10

[0140] The industrial catalyst is designated as D-CAT-10.

[0141] Performance testing

[0142] Test 1: Catalyst performance testing was conducted using a self-made micro-atmospheric pressure evaluation device, such as... Figure 2 As shown, the catalyst is packed in Figure 2 The catalyst was placed in reactor 6. The catalyst particle size was 40-60 mesh, and the loading was 0.2 g (0.2 mL, reaction tube inner diameter 6 mm), with a bed height of 9 mm. First, the catalyst sample was reduced at 850℃ in an H2 atmosphere for 2 h. After reduction, the reactor temperature was lowered to the reaction temperature of 750℃, and the reaction was carried out at a carbon space velocity of 20000 h⁻¹. -1The catalytic performance of the catalyst was evaluated under the conditions of a water-to-carbon ratio of 4 and a water-to-hydrogen ratio of <7.5. The carbon space velocity (CSH) mentioned above refers to the CSH under laboratory conditions. During the reaction, the flow rates of H2 and CH4 were controlled by mass flow meters, and the water feed rate was controlled by a micro-pump. H2, CH4, and water were first heated in a preheater and then mixed uniformly in a mixer before entering the reactor. Both the preheater and the reactor were heated by electric heating wires, and the inner walls were equipped with K-type thermocouples. The preheating and reaction temperatures were measured and controlled by a temperature controller. After the system stabilized, the reaction tail gas was analyzed online using an Agilent 8860 gas chromatograph. The conversion rate of methane was calculated using the following formula. The specific test results of the catalysts obtained in the examples and comparative examples are shown in Table 1.

[0143] Methane conversion rate (X):

[0144] ;

[0145] In the formula: The percentage (%) of each component in the chromatographically analyzed conversion gas.

[0146] Test 2: The specific surface area and pore structure of the hydrogen production catalysts prepared in Examples 1-9 and Comparative Examples 1-10 should be determined. The specific method is as follows: Approximately 0.1 g of sample was weighed, pretreated by degassing at 200°C for 6 h, and then tested using nitrogen as the adsorbent at -196°C in a liquid nitrogen environment. The pore volume, pore size, and specific surface area of ​​the catalyst were calculated from the adsorption-desorption curves using the Barrett-Joyner-Halenda (BJH) method. The specific results are shown in Table 1.

[0147] Test 3: The grain size of the active component in the hydrogen production catalysts prepared in Examples 1-9 and Comparative Examples 1-10 should be determined. The specific method is as follows: X-ray diffraction (XRD). Before testing, the samples were pressed into thin sheets. A Rigaku Smart-lab3 diffractometer was used with a Cu-Ka target line, an incident wavelength of 1.54056 Å, a scanning range of 0° to 90°, and a scanning speed of 10° / min. The NiO grain sizes of the series of catalysts were calculated using the Scherrer equation and are shown in Table 1.

[0148] Test 4: The side pressure strength of the hydrogen production catalysts prepared in Examples 1-9 and Comparative Examples 1-10 should be measured. The specific method is as follows: The formed catalyst particles are placed on the sample platform of the strength tester (Jinan Yinuo Century Test Instrument Co., Ltd., 100KNSCR) according to the pore direction. Pressure is applied uniformly and gradually to the catalyst until it breaks, and the side pressure strength of the catalyst is measured. The specific results are shown in Table 1.

[0149] Test 5: The carbon content in the unloaded samples of the hydrogen production catalysts prepared in Examples 1-9 and Comparative Examples 1-10 should be determined after evaluation, using an HIR-944C infrared carbon-sulfur analyzer and a matching SK2 high-pressure tubular combustion furnace.

[0150] The content of components such as nickel oxide in the hydrocarbon steam reforming catalyst of this invention was determined by a ZSX Primus II X-ray fluorescence spectrometer (XRF).

[0151] Table 1. Performance test results of the examples and comparative examples.

[0152] .

[0153] As shown in Table 1, step 1) of the calcination-quenching-calcination process after support formation is a key step in the generation of carbide, and plays a crucial role in providing suitable strength, pore structure, and specific surface area for the catalyst of this invention. The catalyst prepared using this method exhibits excellent anti-coking performance, high strength, large specific surface area and pore volume, higher methane conversion rate than existing industrial catalysts, and good dispersion of the active component NiO, with well-controlled grain size. The use of an atmosphere of N2:H2O=1:0.5 during support calcination helps in the formation of the catalyst's pore structure and the stability of its strength. Repeating the impregnation of the active component under ultrasonic conditions twice significantly increases the loading and dispersion of the active component in the catalyst, thereby improving the methane conversion rate and stability. The catalyst exhibits the highest activity and best performance in all aspects when the weight ratio of γ-Al2O3:calcium aluminate cement:calcium carbonate in the support is 1:1.25:0.25, and the nickel oxide content in the finished catalyst is 16.7wt%. The optimal conditions for carbide formation, with the carrier initially calcined at 1450℃, quenched at 30℃, and then calcined again at 1100℃, were the best for the formation of carbide and the resulting material exhibited the best strength and pore structure. Graphite and guar gum powder acted as effective binders and pore-forming agents, facilitating the formation of the pore structure and the loading of the active component, nickel.

[0154] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a hydrogen production catalyst, characterized in that, Includes the following steps: 1) Weigh γ-Al2O3, calcium aluminate cement and calcium carbonate and mix them. Then add binder and pore-forming agent, ball mill and mix thoroughly. After adding deionized water, press and mold. Under the atmosphere of nitrogen and water vapor, perform the first calcination to obtain the crude carrier product a. Immediately immerse the calcined crude carrier product a in deionized water while hot and quench it. After cooling, obtain the crude carrier product b. Calcin the crude carrier product b again in the atmosphere of nitrogen to obtain the carrier. 2) The support is placed in a nickel nitrate solution, ultrasonically impregnated for the first time, filtered, and dried; then it is placed in a nickel nitrate solution again for a second ultrasonic impregnation, filtered, and calcined in air to decompose, thus obtaining the hydrogen production catalyst. Step 1) The specific operation of the initial roasting is: roasting at 1300℃~1550℃ for 4~8 hours; Step 1) The specific operation of the second roasting is: roasting at 1000℃~1350℃ for 10min~30min; In step 1), the mass ratio of γ-Al2O3, calcium aluminate cement, and calcium carbonate is 1:1.2~1.3:0.2~0.

3.

2. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: In step 1), the volume ratio of nitrogen to water vapor is 1:0.4~0.

6.

3. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: The specific operation of quenching by immersion in deionized water in step 1) is as follows: immerse in deionized water at 15℃~150℃ for quenching for 10min~30min.

4. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: Step 1) The mass ratio of γ-Al2O3, binder and pore-forming agent is 100:3~6:2-4.

5. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: Step 1) The binder is one or more of graphite, paraffin wax, and stearic acid; the pore-forming agent is one or more of guar gum powder, nitrate, and carbonate.

6. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: In the hydrogen production catalyst described in step 2), the active component, calculated as nickel oxide, is 10~18 wt%.

7. The application of the hydrogen production catalyst prepared by the preparation method according to any one of claims 1 to 6, characterized in that: Application in hydrogen production via hydrocarbon steam reforming.

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