Preparation method and application of hydrogen production catalyst

Abstract

The invention discloses a preparation method and application of a hydrogen production catalyst, 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, mixing, adding a binder and a pore-forming agent, carrying out ball-milling mixing, adding deionized water, carrying out compression molding, and roasting in the atmosphere of nitrogen and water vapor; immediately immersing into deionized water to quench while hot, and cooling; roasting again in a nitrogen atmosphere to obtain a carrier; 2, the carrier is subjected to ultrasonic soaking in a nickel nitrate solution twice, filtering and drying are conducted, the carrier is placed in the air atmosphere to be roasted and decomposed, and the hydrogen production catalyst.The hydrogen production catalyst obtained through the preparation method is high in activity and stability, has high carbon deposition resistance and can be applied to hydrogen production through hydrocarbon steam conversion reaction.

Description

Technical Field

[0001] The invention discloses a preparation method of a hydrogen production catalyst and application thereof, belonging to the technical field of catalysts. Background Art

[0002] Hydrogen has been gaining more and more attention due to its wide range of uses, high efficiency and environmental protection, and as a carrier that can link different forms of energy. Hydrocarbon steam reforming is the most widely used hydrogen production method in industrial applications, with low investment, mature and reliable technology, flexible and convenient operation, and low cost.

[0003] The core part of hydrocarbon steam reforming to produce hydrogen is the reforming reaction, and the reforming catalyst is the key to the reforming reaction. Commonly used reforming catalysts are mainly nickel-based catalysts with relatively low prices and excellent activity. Nickel-based catalysts are mainly divided into two categories: pre-sintered type and potassium-containing type. Pre-sintered catalysts are generally made of high-temperature pre-sintered alumina as a carrier, and then impregnated with the active component nickel; this type of catalyst has a low specific surface area and poor resistance to carbon deposition. The traditional way to solve the carbon deposition problem is to mix potassium nephrite with the active component and then shape it to obtain a potassium-containing catalyst, using alkali metals to achieve the purpose of anti-carbon deposition; but the addition of potassium alkali reduces the activity of the catalyst, and as the reaction proceeds, potassium alkali is easily lost, resulting in poor stability of the catalyst.

[0004] Chinese patent CN113198544A discloses a honeycomb catalyst for treating tail gas and other industrial waste gases. In the process of preparing the carrier, the catalyst is melted at high temperature and then rapidly cooled. The catalyst is then mixed with active components, broken up, and aged. The patent does not generate the key catorite component and only involves the catalyst having low shrinkage and uniform pores, but cannot achieve the anti-coking effect.

[0005] Chinese patent CN107321354B discloses a high-temperature, high-selectivity carbon dioxide methanation catalyst and a preparation method thereof. The catalyst is improved on the basis of the traditional impregnation method. First, a magnesium aluminum spinel carrier is prepared by a hydrothermal synthesis method, and then nickel nitrate is used as an impregnation liquid to uniformly load the nickel-containing component onto the carrier; finally, the impregnated catalyst precursor is acid-washed to make the nickel oxide distributed on the carrier in an "egg yolk type"; hydrogen is more conducive to diffusion into the interior of the catalyst due to its small molecule and large diffusion coefficient, thereby increasing the hydrogen-carbon ratio inside the catalyst, and the increase in the hydrogen-carbon ratio can significantly improve the selectivity of the catalyst, but cannot significantly improve the anti-coking effect of the catalyst.

[0006] The document "Focus on the Multiple Properties and Quenching of Tricalcium Aluminate" introduces the changes in the form of tricalcium aluminate, a cement component, in cement after high-temperature quenching treatment, but does not involve its application in the field of catalysts and its application in anti-coking effects.

[0007] Traditional hydrocarbon steam reforming hydrogen production catalysts have a series of problems such as low specific surface area, easy loss of potash and alkali, poor anti-coking performance, and poor stability. With the continuous expansion of the range of hydrogen production raw materials in recent years, higher requirements have been put forward for the activity, stability and other properties of hydrocarbon steam reforming hydrogen production catalysts, especially the anti-coking ability of the catalyst.

[0008] How to overcome the shortcomings of existing nickel-based catalysts and produce catalysts with high activity, high stability and strong resistance to carbon deposition is the 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 deficiencies 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 comprises the following steps: 1) Weigh γ-Al2O3, calcium aluminate cement and calcium carbonate, mix them, add a binder and a pore-forming agent, mix them thoroughly by ball milling, add deionized water and press them into shape, and perform a primary roasting in an atmosphere of nitrogen and water vapor to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in deionized water while hot to quench, and cool to obtain a carrier crude product b; roast the carrier crude product b again in a nitrogen atmosphere to obtain a carrier; 2) The carrier is placed in a nickel nitrate solution for the first ultrasonic impregnation, filtered and dried; then placed in the nickel nitrate solution for the second ultrasonic impregnation, filtered and dried; placed in an air atmosphere for calcination and decomposition to obtain a hydrogen production catalyst.

[0011] Step 1) The volume ratio of nitrogen to water vapor is 1:0.4-0.6.

[0012] Step 1) The specific operation of the initial calcination is: calcination at 1300° C. to 1550° C. for 4 to 8 hours.

[0013] The specific operation of the re-calcination in step 1) is: calcination at 1000° C. to 1350° C. for 10 min to 30 min.

[0014] The specific operation of immersing in deionized water for quenching in step 1) is: immersing in deionized water at 15° C. to 150° C. for quenching for 10 min to 30 min.

[0015] Step 1) The mass ratio of γ-Al2O3, calcium aluminate cement and calcium carbonate is 1:1.2~1.3:0.2~0.3.

[0016] Step 1) The mass ratio of the γ-Al2O3, the binder and the pore former is 100:3~6:2-4.

[0017] Step 1) The binder is one or more of graphite, paraffin, and stearic acid; the pore-forming agent is one or more of sesbania powder, nitrate, and carbonate.

[0018] In the hydrogen production catalyst described in step 2), the active component is calculated as nickel oxide (referred to as nickel oxide), and the amount is 10-18wt%. Preferably, in the hydrogen production catalyst described in step 2), the active component is calculated as nickel oxide, and the amount is 10.2-17.8wt%. Further preferably, in the hydrogen production catalyst described in step 2), the active component is calculated as nickel oxide, and the amount is 16.7wt%. In the present invention, the mass percentage of the active component is the mass percentage of nickel oxide.

[0019] The hydrogen production catalyst prepared by the preparation method is used in the production of hydrogen by steam reforming reaction of hydrocarbons. Specifically, the hydrogen production catalyst can be reduced to the active component nickel under hydrogen atmosphere at 800°C to 1000°C, and is suitable for steam reforming reaction with light hydrocarbons, oilfield gas or natural gas as raw materials to produce product hydrogen.

[0020] The steam reforming reaction, in an industrial device, has the following reaction conditions: the reforming furnace inlet temperature is 400°C to 600°C, the outlet temperature is 700°C to 850°C, the carbon space velocity is 600h -1 -1000h -1 , water-carbon ratio is 2.0~4.5, and pressure is 2.0~4.0MPa.

[0021] The calcium aluminate cement described in step 1) is pure calcium aluminate cement, and the Al2O3 content:CaO content=50:50.

[0022] The frequency of the ultrasonic wave in step 2) is 20kHz-60kHz.

[0023] Step 2) the calcination in air atmosphere is calcination in a muffle furnace.

[0024] Step 1) The ball milling time is 2 to 4 hours.

[0025] Step 1) The shape of the carrier includes Raschig ring, four-hole cylinder, seven-hole cylinder, seven-rib wheel and other porous spherical or cylindrical shapes.

[0026] The specific operation of drying in step 2) is: drying at 120°C to 180°C for 8h to 24h.

[0027] The immersion time of the first ultrasonic immersion in step 2) is 30 min to 60 min; the immersion time of the second ultrasonic immersion in step 2) is 30 min to 60 min.

[0028] The frequency of the ultrasonic wave in step 2) is 20kHz-60kHz.

[0029] The concentration of the nickel nitrate solution in step 2) is 100-400 g / L. Preferably, the concentration of the nickel nitrate solution in step 2) is 200 g / L.

[0030] The specific operation of the calcination and decomposition in step 2) is: calcination and decomposition at 350° C. to 550° C. for 2 h to 8 h.

[0031] Step 2) The muffle furnace refers to calcination in an air atmosphere.

[0032] The hydrogen production catalyst can be prepared by the above method. The obtained hydrogen production catalyst includes the following components in mass percentage: the active component is calculated as nickel oxide (referred to as nickel oxide) 10-18wt%, catorite 5-15wt%, ɑ-Al2O3 30-40wt%, CaO 5-15wt%, and the balance is calcium aluminate.

[0033] The hydrogen production catalyst has a pore volume of 0.172-0.278 cm 3 / g, specific surface area 58.79~86.9m 2 / g, lateral compression strength 321~407N / particle, bulk density 0.80~1.20kg / L.

[0034] The applicant found in the study that the water-carbon ratio is an extremely important and sensitive process parameter in the hydrocarbon steam reforming reaction. Improving the water-carbon ratio can greatly reduce the carbon deposition on the catalyst, because water vapor can react with the carbon deposits on the catalyst as follows: C+H2O=CO+H2 The active oxygen in the water vapor oxidizes the C deposited during the conversion process into gaseous CO. However, a too high water-carbon ratio will increase energy consumption, increase the pressure difference between the inlet and outlet of the converter, increase the growth rate of nickel grains, and be detrimental to the stability of the reaction system.

[0035] Katoite, i.e., silicon-free hydrogen salt, has a general chemical formula of Ca3Al2(O4H4)3, and can be obtained from the final hydrated stable phase of calcium aluminate, etc., with a considerable content of OH - , while OH - It also contains a large amount of active oxygen, which can provide oxygen to the active metal components in the catalyst. And the decomposition of catorite can generate H2O: Ca3Al2(O4H4)3=3Ca(OH)2+Al2O3+3H2O A large amount of OH in catorite -The generation of H2O achieves the effect of increasing the water-carbon ratio. 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, thereby improving the catalyst's stability and extending its life.

[0036] Compared with the prior art, the present invention has the following beneficial effects: 1. The preparation method of the hydrogen production catalyst of the present invention comprises the following steps: calcination-quenching-calcination is used to generate a carrier containing a large amount of OH - The catorite component containing active oxygen is beneficial to inhibiting the carbonization of the catalyst, and can oxidize the carbon deposits already formed on the catalyst into CO and CO2, thereby enhancing the anti-carbon performance of the catalyst, thereby improving the stability and life of the catalyst, and can better adapt to a wider range of hydrogen production raw materials and be better used in the application of hydrogen production by hydrocarbon steam reforming reaction.

[0037] 2. The preparation method of the hydrogen production catalyst of the present invention utilizes the huge temperature difference between calcination and quenching and the rapid change of temperature. The calcination-quenching-calcination process in step 1) is a key step in generating a catalyst having a catonite component, so that the deionized water in the catalyst pores instantly undergoes a phase change and vaporizes into water vapor. The water vapor rapidly expands in the pores, greatly increasing the number of mesoporous structures of the catalyst, increasing the specific surface area of ​​the catalyst, and thereby increasing the dispersion of the active component nickel.

[0038] 3. The preparation method of the hydrogen production catalyst of the present invention can adjust the composition, structure and carrier amount of the obtained hydrogen production catalyst. Compared with the hydrogen production catalyst prepared by the traditional impregnation method, the hydrogen production catalyst prepared by the present invention does not need to add additional carbon-resistant potash additives, has no effect of potash on the activity of the catalyst, and has no risk of potash loss affecting the downstream. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The X-ray diffraction (XRD) diagram of the catalyst of the present invention.

[0040] Figure 2 It is a schematic diagram of the process of the micro normal pressure evaluation device in performance testing.

[0041] Among them: 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 DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments, wherein embodiment 1 is the best embodiment. The comparative example is designed by the applicant to compare the effects of the embodiments, and the specific design is as follows.

[0043] γ-Al2O3 was purchased from Wenzhou Jingjing Alumina Co., Ltd., Zhejiang Province, model Q / WYL01-2001; Calcium aluminate cement was purchased from Shandong Refractory Materials Co., Ltd., No. 75 cement, in which the Al2O3:CaO content was 50:50; The nickel nitrate solution is an aqueous solution of nickel nitrate, and the solvent is water; The industrial catalyst used in Comparative Example 10 (labeled D-CAT-10) was purchased from Chengdu Shengli Technology Co., Ltd., model Z118Y, with an active component (calculated as nickel oxide) content of 19%; The equipment used for ultrasonic immersion was purchased from Kunshan Ultrasonic Instrument Co., Ltd., model KQ2200, ultrasonic input power 100 W, frequency 20 kHz-60 kHz; Step 1) The equipment used for the two roastings is from Luoyang Juxing Co., Ltd., model GWL-1200XAD; The muffle furnace calcination used in the embodiments and comparative examples refers to calcination in an air atmosphere.

[0044] In order to reduce variables, the shapes of the carriers pressed and molded in the examples and comparative examples were all four-hole cylindrical, with a diameter of 1.1 cm and a column height of 1.6 cm.

[0045] Example 1 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of high-temperature pre-burned calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until it is completely cooled; the cooled carrier is roasted again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The carrier was placed in 200 mL of 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 minutes, filtered and dried in an oven at 150°C for 12 hours, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 minutes, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 hours to obtain a hydrogen production catalyst, labeled CAT-1. Nickel oxide accounts for 16.7 wt% of the hydrogen production catalyst.

[0046] Example 2 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 120g of high temperature pre-burned calcium aluminate cement, and 20g of calcium carbonate, and then add 3g of graphite and 2g of sesbania powder, ball mill for 2h to fully mix the components, add deionized water and press into shape, and the subsequent steps are the same as in Example 1; 2) Step 2 is the same as in Example 1, and a hydrogen production catalyst is obtained, which is labeled CAT-2. Nickel oxide accounts for 15.1 wt% in the hydrogen production catalyst.

[0047] Example 3 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 130g of high temperature pre-burned calcium aluminate cement, and 30g of calcium carbonate, and then add 6g of graphite and 4g of sesbania powder, ball mill for 4h to fully mix the components, add deionized water and press into shape, and the subsequent steps are the same as in Example 1; 2) Step 2 is the same as in Example 1, and a hydrogen production catalyst is obtained, which is labeled CAT-3. Nickel oxide accounts for 17.8 wt% in the hydrogen production catalyst.

[0048] Example 4 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of high-temperature pre-burned calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1300℃ for 4h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.4; immediately immerse the roasted carrier in 30℃ deionized water for quenching for 20min until it is completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1000℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, labeled CAT-4. Nickel oxide accounts for 11.3 wt% in the hydrogen production catalyst.

[0049] Example 5 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of high-temperature pre-burned calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder. Ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1550℃ for 4h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.6 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1350℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) Step 2) is the same as in Example 1, to obtain a hydrogen production catalyst, labeled CAT-5. Nickel oxide accounts for 14.3 wt% in the hydrogen production catalyst.

[0050] Example 6 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of high-temperature pre-burned calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; the roasted carrier crude product a is immediately and completely immersed in 15℃ deionized water while hot and quenched for 30min until it is completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is again roasted at 1100℃ for 20min in a nitrogen atmosphere to obtain a carrier; 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, labeled CAT-6. Nickel oxide accounts for 13.9 wt% in the hydrogen production catalyst.

[0051] Example 7 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of high-temperature pre-burned calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; the roasted carrier crude product a is immediately and completely immersed in 150℃ deionized water while hot and quenched for 10min until it is completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is again roasted at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) Step 2) is the same as in Example 1, obtaining a hydrogen production catalyst, labeled CAT-7. Nickel oxide accounts for 10.2 wt% in the hydrogen production catalyst.

[0052] Example 8 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) The steps for preparing the carrier are the same as those in Example 1; 2) The carrier was placed in 200 mL of 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 30 minutes, filtered and dried in an oven at 120°C for 8 hours, and then placed in the nickel nitrate solution again for ultrasonic immersion for 30 minutes, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 350°C for 2 hours to obtain a hydrogen production catalyst, labeled CAT-8. Nickel oxide accounts for 14.2 wt% of the hydrogen production catalyst.

[0053] Example 9 The preparation method of the hydrogen production catalyst of this embodiment comprises the following steps: 1) The steps for preparing the carrier are the same as those in Example 1; 2) The carrier was placed in 200 mL of 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 60 minutes, filtered and dried in an oven at 180°C for 24 hours, and then placed in the nickel nitrate solution again for ultrasonic immersion for 60 minutes, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 550°C for 8 hours to obtain a hydrogen production catalyst, labeled CAT-9. Nickel oxide accounts for 17.3 wt% of the hydrogen production catalyst.

[0054] Comparative Example 1 In this comparative example, step 1) there is a primary roasting, no quenching, and no re-roasting; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed in a volume ratio of N2:H2O=1:0.5 to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-1.

[0055] Comparative Example 2 In step 1) of this comparative example, there is initial roasting and quenching, but after quenching, there is no re-roasting; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and calcine at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; the calcined carrier crude product a is immediately and completely immersed in 30℃ deionized water while hot and quenched for 20min, until all the carriers are completely cooled, and then placed in an oven at 120℃ for drying for 12h to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-2.

[0056] Comparative Example 3 This comparative example changes the calcination atmosphere; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and calcine in a muffle furnace at 1450℃ for 6h to obtain a carrier crude product a; immediately immerse the calcined carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is calcined again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-3.

[0057] Comparative Example 4 This comparative example did not use ultrasonic impregnation; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The carrier was immersed in 200 mL of 200 g / L nickel nitrate solution for 40 min, filtered and dried in an oven at 150° C. for 12 h, then immersed in the nickel nitrate solution again for 40 min, filtered and dried, and calcined in a muffle furnace at 450° C. for 6 h to obtain hydrogen production catalyst D-CAT-4.

[0058] Comparative Example 5 This comparative example step 1) the roasting temperature is too low; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 800℃ for 6h in an atmosphere of nitrogen and water vapor mixed in a volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; the roasted carrier crude product a is immediately immersed in 30℃ deionized water while hot and quenched for 20min until it is completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 800℃ for 20min in a nitrogen atmosphere to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed under ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-5.

[0059] Comparative Example 6 Step 2) of this comparative example only uses a single ultrasonic immersion; The preparation method of the hydrogen production catalyst in this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 125g of calcium aluminate cement, and 25g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The support was placed in 200 mL of 200 g / L nickel nitrate solution and immersed under ultrasonic conditions for 40 min, then filtered and dried, and then placed in a muffle furnace and calcined and decomposed at 450 °C for 6 h to obtain the hydrogen production catalyst D-CAT-6.

[0060] Comparative Example 7 This comparative example changes step 1) carrier component; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O 3、 Calcium carbonate is pressed into shape after adding deionized water, and is calcined at 1450°C for 6 hours in an atmosphere of nitrogen and water vapor mixed in a volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; the calcined carrier crude product a is immediately and completely immersed in 30°C deionized water while hot and quenched for 20 minutes until it is completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is calcined again at 1100°C for 20 minutes in a nitrogen atmosphere to obtain a carrier; 2) The carrier was placed in 200 mL of 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution for ultrasonic immersion for 40 min again, filtered and dried, placed in a muffle furnace at 450°C for calcination and decomposition for 6 h to obtain the hydrogen production catalyst D-CAT-7.

[0061] Comparative Example 8 This comparative example changes the proportion of components in step 1), and the proportion of calcium aluminate cement and calcium carbonate is reduced; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 50g of calcium aluminate cement, and 5g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-8.

[0062] Comparative Example 9 This comparative example changes the proportion of components in step 1), and increases the proportion of calcium aluminate cement and calcium carbonate; The preparation method of the hydrogen production catalyst of this comparative example comprises the following steps: 1) Weigh 100g of γ-Al2O3, 200g of calcium aluminate cement, and 50g of calcium carbonate, and then add 5g of graphite and 3g of sesbania powder, ball mill for 3h to fully mix the components, add deionized water and press into shape, and roast at 1450℃ for 6h in an atmosphere of nitrogen and water vapor mixed volume ratio of N2:H2O=1:0.5 to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in 30℃ deionized water while hot and quench for 20min until completely cooled to obtain a carrier crude product b; the cooled carrier crude product b is roasted again at 1100℃ in a nitrogen atmosphere for 20min to obtain a carrier; 2) The carrier was placed in 200 mL of a 200 g / L nickel nitrate solution, immersed in ultrasonic conditions for 40 min, filtered and dried in an oven at 150°C for 12 h, and then placed in the nickel nitrate solution again for ultrasonic immersion for 40 min, filtered and dried, and placed in a muffle furnace for calcination and decomposition at 450°C for 6 h to obtain a hydrogen production catalyst D-CAT-9.

[0063] Comparative Example 10 Take the industrial catalyst marked D-CAT-10.

[0064] Performance Testing Test 1: The catalyst performance test was carried out in a self-made micro atmospheric pressure evaluation device. Figure 2 As shown, the catalyst is loaded in Figure 2The catalyst was placed in the reactor 6. The catalyst particle size was 40-60 mesh particles, the loading amount was 0.2 g (0.2 mL, the inner diameter of the reaction tube was 6 mm), and the loading bed height was 9 mm. First, the catalyst sample was reduced at 850 ° C in a H2 atmosphere for 2 h. After the reduction was completed, the temperature in the reactor was lowered to the reaction temperature of 750 ° C. At a carbon space velocity of 20000 h -1 , water-carbon ratio of 4, water-hydrogen ratio <7.5, the catalytic performance of the catalyst was evaluated. The above carbon space velocity is the carbon space velocity under laboratory conditions. During the reaction, the flow rates of H2 and CH4 are controlled by mass flow meters, and the water feed rate is controlled by a micro pump. H2, CH4 and water are first heated in a preheater and then mixed evenly in a mixer before entering the reactor. The preheater and the reactor are both heated by electric furnace wires, and the inner wall is equipped with a K-type thermocouple. The preheating and reaction temperatures are measured and controlled by a temperature controller. After the system is stable, an Agilent 8860 gas chromatograph is used to analyze the reaction exhaust gas online. The conversion rate of methane is calculated by the following formula. The specific test results of the catalysts obtained in the embodiments and comparative examples are shown in Table 1; Methane conversion rate (X): ; Where: It is the percentage (%) of each component in the conversion gas analyzed by chromatography.

[0065] Test 2: The specific surface area and pore structure of the hydrogen production catalyst prepared in Examples 1-9 and Comparative Examples 1-10 were measured. The specific method is as follows: weigh about 0.1 g of the sample, degas for 6 hours at 200°C, and then test it in a liquid nitrogen environment at -196°C using nitrogen as an adsorbent. The Barrett-Joyner-Halenda (BJH) method was used to calculate the pore volume, pore diameter and specific surface area of ​​the catalyst based on the adsorption-desorption curve. The specific results are shown in Table 1.

[0066] Test 3: The crystal size of the active component of the hydrogen production catalyst prepared in Examples 1-9 and Comparative Examples 1-10 was determined. The specific method is as follows: X-ray diffraction (XRD), the sample was pressed into a thin sheet before testing, and a Smart-lab 3 diffractometer of Rigaku Corporation was used, using a Cu-Kɑ target line, an incident wavelength of 1.54056Å, a scanning range of 0°~90°, and a scanning speed of 10° / min. The NiO crystal size of the series of catalysts calculated by the Scherrer equation is shown in Table 1.

[0067] Test 4: The lateral compressive strength of the hydrogen production catalyst prepared in Examples 1-9 and Comparative Examples 1-10 was measured. The specific method is as follows: the formed catalyst particles are placed on the sample platform of a strength tester (Jinan Yinuo Century Testing Instrument Co., Ltd., 100KNSCR) according to the hole position, and pressure is gradually applied to the catalyst uniformly until it breaks, and the lateral compressive strength of the catalyst is measured. The specific results are shown in Table 1.

[0068] 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 a HIR-944C infrared carbon-sulfur analyzer and a matching SK2 high-pressure tubular combustion furnace.

[0069] The content of nickel oxide and other components in the hydrocarbon steam reforming catalyst of the present invention is determined by a ZSX Primus II type X-ray fluorescence spectrometer (XRF).

[0070] Table 1 Performance test results of embodiments and comparative examples .

[0071] It can be seen from Table 1 that the calcination-quenching-calcination process after the carrier is formed in step 1) is a key step in the formation of catorite, and plays a key role in providing the catalyst of the present invention with suitable strength, pore structure and specific surface area. The catalyst prepared by this method has excellent anti-coking performance, high strength, large specific surface area and pore volume, and the methane conversion rate is higher than that of existing industrial catalysts. The active component NiO has good dispersion and the grain size is well controlled. The atmosphere of N2:H2O=1:0.5 is used during the carrier calcination, which is conducive to the formation of the catalyst pore structure and the stability of the strength. When the carrier is impregnated with the active component, the impregnation is repeated twice under ultrasonic conditions, which can significantly increase the loading amount and dispersion of the active component in the catalyst, thereby improving the methane conversion rate and stability. When the weight ratio of γ-Al2O3: calcium aluminate cement: calcium carbonate in the carrier is 1:1.25:0.25, and the nickel oxide content in the obtained finished catalyst is 16.7wt%, the catalyst activity is the highest and the performance in all aspects is the best. The carrier is first calcined at 1450℃, quenched at 30℃, and calcined again at 1100℃, which is most conducive to the formation of catonite, and has the best strength and pore structure. Graphite and sesbania powder play the role of good binder and pore former, which is conducive to the formation of pore structure and the loading of active component nickel.

[0072] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a hydrogen production catalyst, characterized in that: The steps include: 1) Weigh γ-Al2O3, calcium aluminate cement and calcium carbonate, mix them, add a binder and a pore-forming agent, mix them thoroughly by ball milling, add deionized water and press them into shape, and perform a primary roasting in an atmosphere of nitrogen and water vapor to obtain a carrier crude product a; immediately immerse the roasted carrier crude product a in deionized water while hot to quench, and cool to obtain a carrier crude product b; roast the carrier crude product b again in a nitrogen atmosphere to obtain a carrier; 2) The carrier is placed in a nickel nitrate solution for the first ultrasonic impregnation, filtered and dried; then placed in the nickel nitrate solution for the second ultrasonic impregnation, filtered and dried; placed in an air atmosphere for calcination and decomposition to obtain a hydrogen production catalyst.

2. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: 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: Step 1) The specific operation of the initial calcination is: calcination at 1300° C. to 1550° C. for 4 to 8 hours.

4. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: The specific operation of the re-calcination in step 1) is: calcination at 1000° C. to 1350° C. for 10 min to 30 min.

5. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: The specific operation of immersing in deionized water for quenching in step 1) is: immersing in deionized water at 15° C. to 150° C. for quenching for 10 min to 30 min.

6. The method for preparing a hydrogen production catalyst according to claim 1, characterized in that: Step 1) The mass ratio of γ-Al2O3, calcium aluminate cement and calcium carbonate is 1:1.2~1.3:0.2~0.

3.

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

8. 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, and stearic acid; the pore-forming agent is one or more of sesbania powder, nitrate, and carbonate.

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

10. Use of the hydrogen production catalyst prepared by the preparation method according to any one of claims 1 to 9, characterized in that: Application in hydrogen production from hydrocarbon steam reforming reaction.

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