Catalyst for producing hydrogen and carbon black by catalytic cracking of methane as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for producing hydrogen and carbon black by catalytic cracking of methane as well as a preparation method and application of the catalyst. The preparation method of the catalyst comprises the following steps: uniformly mixing the main active component, the auxiliary active component and the precursor of the carrier in water, adding the dispersing agent, dropwise adding the obtained mixed solution into the aqueous solution of the complexing agent, then mixing with the aqueous solution containing ammonium ions, and drying by distillation, drying, roasting, crushing and screening to obtain the catalyst. And obtaining the catalyst for producing hydrogen and carbon black by catalytic cracking of methane. The catalyst provided by the invention is prepared by the preparation method. The catalyst provided by the invention has the advantages of high methane conversion rate, strong carbon black production capacity, good stability, simple preparation process, low cost and the like.

Description

Technical Field

[0001] The invention relates to a catalyst for producing hydrogen and carbon black by catalytic cracking of methane, and a preparation method and application thereof, belonging to the technical field of methane catalytic cracking catalysts. Background Art

[0002] With the reduction of fossil energy and the environmental pollution problems caused by its use, it is urgent to develop clean and efficient new energy to replace fossil energy. Hydrogen energy, as an efficient and clean secondary energy source, is considered to be one of the most promising alternative energy sources and clean fuels. At present, the main methods of industrial hydrogen production are coal gasification hydrogen production, methane partial oxidation hydrogen production, methane steam reforming hydrogen production, biomass hydrogen production and water electrolysis hydrogen production. Coal hydrogen production technology has problems such as backward process and low hydrogen production efficiency. Biomass hydrogen production is an industrial technology that conforms to the sustainable development strategy, but the catalyst activity is low and the reaction process fluctuates. The process of water electrolysis hydrogen production is simple, pollution-free, green and environmentally friendly, but the reaction process has high energy consumption and high production cost, resulting in a certain waste of resources. Therefore, the application of water electrolysis hydrogen production is subject to certain restrictions.

[0003] Natural gas (mainly CH 4 ) is considered to be the best raw material for hydrogen production. The methane catalytic cracking (MCD) hydrogen production process can directly decompose methane to obtain high-purity hydrogen without carbon oxides. The process is simple, energy-saving and environmentally friendly. In addition, the carbon materials (carbon nanotubes, carbon black, etc.) generated during the MCD reaction are widely used in many fields due to their excellent physical and chemical properties and have high economic value.

[0004] At present, the catalysts used for natural gas cracking to produce hydrogen mainly include metal-supported catalysts and carbon-based catalysts. Among them, the methane conversion rate of metal catalysts is low, the space velocity is not high, the hydrogen yield is low, and the added value of carbon products is not high. The reaction of carbon-based catalysts needs to be carried out at high temperature, and the methane conversion rate is low, the carbon product has many impurities, and the carbon product is difficult to separate.

[0005] CN111689467A discloses a method for producing hydrogen by catalyzing methane cracking using activated carbon as a catalyst, which has a high activity in catalyzing methane cracking to produce hydrogen and prolongs the deactivation time of the activated carbon catalyst. However, the carbon product produced by the catalyst contains many types of metal impurities and carbon products, which increases the difficulty of product separation.

[0006] CN114804023A discloses a solid active metal porous nickel metal-molten salt as an active non-supported catalyst, the molten salt used can be recycled and reused, and exhibits good catalytic performance for high-temperature methane cracking. However, the catalyst requires high temperature conditions and the reaction process has high energy consumption.

[0007] CN110227462A discloses a catalyst for producing hydrogen by direct catalytic cracking of methane and its preparation method. The catalyst uses MO / CNFs as a carrier to load the active component Ni, wherein the weight parts of each component are: M element 10-50, MO y 5~70, CNFs 2~45; MO y SiO 2 、ZrO 2 、TiO 2 、Ce (1-x) Zr x O 2 The catalyst is prepared by: y The pretreated CNFs are added to a nickel salt aqueous solution, and then an alkali solution is added to adjust the pH value to 6-8, and the mixture is stirred and allowed to stand, and the obtained precipitate is filtered, washed, and dried to obtain the catalyst. The catalyst has a high methane conversion rate, strong anti-coking ability, and good stability.

[0008] CN110683511A discloses a method for x Fe 3-X -Ca 2 Fe y Al 2-y O 5 The invention also discloses a catalytic oxygen carrier for catalyzing methane to efficiently produce hydrogen by catalyzing methane and cooperating with CO 2 The catalytic oxygen carrier can regulate the occurrence of methane catalytic cracking hydrogen production reaction based on chemical chain cycle and CO 2 The specific steps of the method are as follows: (1) methane cracking stage, in which methane is cracked under the action of the catalytic oxygen carrier to achieve high methane conversion rate and high hydrogen selectivity, and at the same time obtain nanocarbon as a by-product; (2) CO 2 In the reduction stage, high CO is achieved in the presence of reduction catalytic oxygen carriers and nanocarbon. 2 The method achieves continuous and efficient production of high-purity H 2 With CO 2 Gas emission reduction.

[0009] CN113522297A discloses a preparation method and application of a fly ash catalyst for catalytic cracking of methane to produce hydrogen. The preparation method of the catalyst uses Ni and Fe as active components, CeO 2 As a catalyst, fly ash was used as a carrier, and Ni-Fe-CeO was prepared by precipitation followed by impregnation. 2 Fly ash catalyst. The catalyst has a high specific surface area and dispersion, among which CeO 2The addition of can significantly improve the activity of the catalyst in the catalytic cracking of methane to produce hydrogen, and the catalyst has good cycle performance.

[0010] However, the prior art still lacks an efficient method for producing hydrogen and carbon black by catalytic cracking of methane. Summary of the invention

[0011] In order to solve the above technical problems, the purpose of the present invention is to provide a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and its preparation method and application. The catalyst provided by the present invention has the advantages of high methane conversion rate and strong carbon black production capacity.

[0012] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, which comprises the following steps:

[0013] (1) mixing a precursor of a main active component of the catalyst, a precursor of a co-active component and a precursor of a carrier in water to obtain a first mixed solution; adding a dispersant to the first mixed solution and stirring to obtain a second mixed solution;

[0014] (2) adding the second mixed solution dropwise to the complexing agent aqueous solution and stirring evenly to obtain a third mixed solution;

[0015] (3) mixing the third mixed solution with an aqueous solution containing ammonium ions, and stirring them uniformly to obtain a fourth mixed solution;

[0016] (4) evaporating the fourth mixed solution to dryness to obtain a fluffy substance, drying and roasting the fluffy substance, and then crushing and sieving the fluffy substance to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black;

[0017] Wherein, the main active component includes one or a combination of nickel, cobalt, nickel oxide and cobalt oxide;

[0018] The auxiliary active component includes one or more metals and / or metal oxides selected from Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La;

[0019] The carrier includes MgO, γ-Al 2 O 3 、SiO 2 、TiO 2 、ZrO 2 MgO-Al 2 O 3 Composite oxide, MgO-SiO 2 One or a combination of composite oxides, graphite and perovskite.

[0020] In the above-mentioned preparation method, preferably, taking the total mass of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black as 100%, it includes: 10% to 50% of the main active component calculated as oxide, 0.1% to 30% of the auxiliary active component calculated as oxide and the balance of the carrier.

[0021] In the above preparation method, preferably, in step (1), the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier respectively include soluble salt compounds of the main active component, the auxiliary active component and the carrier. For example, but not limited to nitrates, chlorides, etc. The precursor of the carrier may also include phosphates and / or sulfates, etc.

[0022] In the above preparation method, preferably, in step (1), the dispersant includes a combination of a first dispersant and a second dispersant, wherein the first dispersant includes one or more of polyethylene glycol, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester and polyoxyethylene alkylamine, etc.; the second dispersant includes one or more of ammonium citrate, polystyrene maleate, hexadecyltrimethylammonium bromide, sodium laurate, polyvinyl alcohol and sodium dodecylbenzene sulfonate, etc. More preferably, the mass ratio of the first dispersant to the second dispersant is 1:(1-2.5), and particularly preferably 1:(1.4-2.2). Further preferably, the dispersant includes a composition of polyethylene glycol (preferably PEG-2000) and ammonium citrate, a composition of fatty alcohol polyoxyethylene ether and polystyrene maleate, a composition of alkylphenol polyoxyethylene ether and cetyltrimethylammonium bromide, a composition of fatty acid polyoxyethylene ester and sodium laurate, a composition of polyoxyethylene alkylamine and polyvinyl alcohol, or a composition of polyoxyethylene lauryl ether and sodium dodecylbenzene sulfonate.

[0023] In the above preparation method, preferably, in step (1), the amount of the dispersant added is 1% to 30% of the total mass of the second mixed solution, more preferably 3 to 25%.

[0024] In the above-mentioned preparation method, preferably, in step (1), a dispersant aqueous solution is added to the first mixed solution, and the mixture is stirred at a constant temperature of 50 to 90° C. for 50 to 200 min, and the stirring speed is 50 to 500 r / min to obtain a second mixed solution. More preferably, a dispersant aqueous solution is added to the first mixed solution, and the mixture is stirred at a constant temperature of 70 to 80° C. for 60 to 180 min, and the stirring speed is 100 to 300 r / min to obtain a second mixed solution. The concentration of the dispersant aqueous solution can be conventionally adjusted by a person skilled in the art, as long as the dispersant addition ratio of the present invention is met.

[0025] In the above-mentioned preparation method, preferably, in step (2), the complexing agent includes an ammonium salt composite complexing agent formed by a combination of one or more of maleic acid, tartaric acid, malic acid, glycine, alginic acid, pyrophosphoric acid and citric acid and an ammonium salt. More preferably, the ammonium salt includes ammonium chloride and / or ammonium nitrate. More preferably, the mass ratio of the combination of one or more of maleic acid, tartaric acid, malic acid, glycine, alginic acid, pyrophosphoric acid and citric acid to the ammonium salt is (4-5):(10-12).

[0026] In the above-mentioned preparation method, preferably, in step (2), the mass ratio of the total amount of the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier in the second mixed solution to the ammonium salt complex complexing agent in the complexing agent aqueous solution is (7-11):(13-18).

[0027] In the above-mentioned preparation method, preferably, in step (2), the complexing agent aqueous solution is prepared by adding a combination of one or more of maleic acid, tartaric acid, malic acid, glycine, alginic acid, pyrophosphoric acid and citric acid and ammonium salt to water, and stirring at a constant temperature of 50 to 90° C. at a speed of 50 to 500 r / min for 50 to 200 min. More preferably, the complexing agent aqueous solution is prepared by adding a combination of one or more of maleic acid, tartaric acid, malic acid, glycine, alginic acid, pyrophosphoric acid and citric acid and ammonium salt to water, and stirring at a constant temperature of 100 to 300 r / min for 60 to 180 min at 70 to 80° C. The concentration of the ammonium salt composite complexing agent in the complexing agent aqueous solution can be conventionally adjusted by a person skilled in the art, as long as the mass ratio of the total amount of the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier to the ammonium salt composite complexing agent is satisfied and the reaction proceeds smoothly.

[0028] In the above preparation method, preferably, in step (2), the dropping speed of adding the second mixed solution dropwise to the complexing agent aqueous solution is 1 to 20 ml / min, more preferably 5 to 10 ml / min.

[0029] In the above preparation method, preferably, step (2) is carried out at 50-90°C.

[0030] In the above-mentioned preparation method, preferably, in step (3), the mass ratio of ammonium ions in the aqueous solution containing ammonium ions to the total amount of the precursor of the main active component, the precursor of the co-active component and the precursor of the carrier in the second mixed solution is (2-4):(7-11).

[0031] In the above-mentioned preparation method, preferably, in step (3), the aqueous solution containing ammonium ions includes an aqueous ammonium salt solution and / or ammonia water. More preferably, the aqueous ammonium salt solution is prepared by adding an ammonium salt to water and stirring at a constant temperature of 50 to 90°C at a speed of 50 to 500 r / min for 50 to 200 min. More preferably, the aqueous ammonium salt solution is prepared by adding an ammonium salt to water and stirring at a constant temperature of 100 to 300 r / min for 60 to 180 min at a speed of 70 to 80°C. The concentration of the aqueous ammonium salt solution and the concentration of the ammonia water can be conventionally adjusted by a person skilled in the art, as long as the mass ratio relationship of the ammonium ions to the total amount of the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier of the present invention is satisfied and the reaction proceeds smoothly.

[0032] In the above preparation method, preferably, in step (3), the ammonium salt includes one or a combination of ammonium bicarbonate, ammonium carbonate and ammonium nitrate.

[0033] In the above preparation method, preferably, in step (3), the third mixed solution and the aqueous solution containing ammonium ions are mixed by flowing into a container.

[0034] In the above preparation method, preferably, step (3) is carried out at 50-90°C.

[0035] In the above-mentioned preparation method, preferably, in step (4), the process of evaporating the fourth mixed solution to dryness specifically includes: evaporating the fourth mixed solution at 65-90°C at a speed of 100-300 r / min, and when the fourth mixed solution is transformed into a viscous wet glue, increasing the stirring speed to 300-500 r / min and the temperature to 90-110°C, and continuing to evaporate until the fluffy material is formed.

[0036] In the above preparation method, preferably, in step (4), the drying temperature is 80 to 150° C. and the drying time is 1 to 24 hours.

[0037] In the above preparation method, preferably, in step (4), the calcination is carried out in a protective atmosphere, and the calcination temperature is 600-1000°C, and the time is 1-10 hours, and the protective atmosphere includes one or a combination of air, nitrogen, argon, helium, neon, etc. More preferably, the calcination temperature is 650-800°C, and the time is 2-6 hours.

[0038] In the above preparation method, preferably, in step (4), the pulverization can be carried out by grinding.

[0039] In the above preparation method, preferably, in step (4), the screening uses a 60-120 mesh sieve, more preferably a 80-120 mesh sieve.

[0040] In the above preparation method, preferably, the auxiliary active component includes one or more metals and / or metal oxides selected from Fe, Zn, Cu, Ce and La.

[0041] In the above preparation method, preferably, the carrier comprises γ-Al 2 O 3 , MgO, perovskite and magnesium aluminum spinel, etc., or a combination of them. Among them, magnesium aluminum spinel is MgO-Al 2 O 3 A type of composite oxide.

[0042] In the above-mentioned preparation method, preferably, taking the total mass of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black as 100%, it includes: 40% to 45% of the main active component calculated as oxide, 15% to 30% of the auxiliary active component calculated as oxide and the balance of the carrier.

[0043] The second aspect of the present invention provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, which is prepared by the above-mentioned method for preparing the catalyst for catalytic cracking of methane to produce hydrogen and carbon black; the general formula of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black is shown in Formula I:

[0044] aX·bY·(100-ab)M Formula I,

[0045] Wherein, X represents the main active component, Y represents the auxiliary active component, and M represents the carrier; a and b represent the mass percentages of components X and Y respectively, and 10≤a≤50, 0.1≤b≤30; the main active component comprises one or a combination of nickel, cobalt, nickel oxide and cobalt oxide; the auxiliary active component comprises one or a combination of metals and / or metal oxides of Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La; the carrier comprises MgO, γ-Al 2 O 3 、SiO 2 、TiO 2 、ZrO 2 MgO-Al 2 O 3 Composite oxide, MgO-SiO 2 One or a combination of composite oxides, graphite and perovskite.

[0046] In the above-mentioned catalyst for catalytic cracking of methane to produce hydrogen and carbon black, preferably, the auxiliary active component includes one or more metals and / or metal oxides selected from Fe, Zn, Cu, Ce and La.

[0047] In the above-mentioned catalyst for catalytic cracking of methane to produce hydrogen and carbon black, preferably, the carrier comprises γ-Al 2 O 3 , MgO, perovskite and magnesium aluminum spinel, etc., or a combination of them. Among them, magnesium aluminum spinel is MgO-Al 2 O 3 A type of composite oxide.

[0048] In the above-mentioned catalyst for catalytic cracking of methane to produce hydrogen and carbon black, preferably, in formula I, 40≤a≤45, 15≤b≤30.

[0049] The third aspect of the present invention provides the use of the above-mentioned catalyst for catalytic cracking of methane to produce hydrogen and carbon black in catalytic cracking of methane to produce hydrogen and carbon black.

[0050] According to a specific embodiment of the present invention, preferably, the application includes: using a fixed bed reactor, under the action of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black, catalytic cracking of the raw gas including methane is carried out to obtain hydrogen and carbon black; wherein, based on the loading amount of the catalyst being 0.5g, the feed flow rate of the raw gas is 10-400ml / min; the reaction temperature of the catalytic cracking is 400-900°C, and the reaction pressure is normal pressure.

[0051] In the above application, preferably, the raw gas includes pure methane and / or other methane-rich gases (such as natural gas after preliminary desulfurization treatment, or refinery gas, etc.).

[0052] In the above application, preferably, based on the loading amount of the catalyst being 0.5 g, the feed flow rate of the raw material gas is 50 to 200 ml / min.

[0053] In the above application, preferably, the reaction temperature of the catalytic cracking is 500-800°C.

[0054] In the above application, preferably, the catalyst for catalytic cracking of methane to produce hydrogen and carbon black is reduced before use, the reduction temperature is 300-900°C, preferably 500-700°C; the reduction method is constant temperature reduction; the hydrogen concentration is 5-90%, preferably 10-40%.

[0055] The technical solution of the present invention has at least the following beneficial effects:

[0056] (1) The present invention adopts a sol-gel method to synthesize a catalyst for catalytic cracking of methane to produce hydrogen and carbon black. During the preparation of the catalyst, a compound dispersant is developed to pretreat a solution containing an active component precursor to disperse the active groups. Compared with the use of a single non-ionic surfactant, the compound dispersant of the present invention can efficiently disperse the main active component and the auxiliary active component into an inert carrier to avoid the phenomenon that the metal is easily agglomerated or unevenly dispersed during the synthesis process, thereby improving the dispersibility of the active component.

[0057] (2) In the process of synthesizing the catalyst for catalytic cracking of methane to produce hydrogen and carbon black by the sol-gel method of the present invention, after a complex is formed by using a specific ammonium salt composite complexing agent and a precursor of an active component, there are fewer free ions. When a hydroxide precipitate is generated, the metal ions (i.e., the active component) are slowly released from the complex, slowing down the precipitation process, and forming an ultrafine hydroxide precipitate, which is conducive to the generation of an ultrafine catalyst powder.

[0058] In summary, the present invention adopts the sol-gel method to synthesize a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the catalyst includes a composite metal oxide containing multiple components. The catalyst has the advantages of good dispersion effect of active components, high methane conversion rate, strong carbon black production ability, good stability, simple preparation process, low cost, etc. The catalyst is used in the reaction of catalytic cracking of methane to produce hydrogen and carbon black, and a higher methane conversion rate and a higher yield of hydrogen and carbon black can be obtained under the conditions of lower reaction temperature and higher space velocity. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is the SEM image of the catalyst prepared in Example 1.

[0060] Figure 2 This is the SEM image of carbon black produced by the catalyst prepared in Example 1.

[0061] Figure 3 This is a mapping diagram of the main active components in the catalyst prepared in Example 1.

[0062] Figure 4 This is the mapping diagram of the main active components in the catalyst prepared in Comparative Example 3. DETAILED DESCRIPTION

[0063] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0064] The raw materials used in the following examples and comparative examples are shown in Table 1.

[0065] Table 1

[0066]

[0067] The catalysts prepared in the following examples and comparative examples were evaluated for performance by the following method: methane catalytic cracking reaction was carried out in a small quartz tube fixed bed reactor, the catalyst loading was 0.5 g, the reaction temperature was 500-800°C, the reaction pressure was normal pressure, the reaction time was 10 h, and the flow rate of methane (purity of 99.99 vol%, commercially available) was 50 ml / min. The components of the reaction product were analyzed by HP-7890 gas chromatograph using the external standard method; the chromatographic column was a capillary column HP-PLOT-Q with a size of 30 m×0.53 mm; two detectors were set, a thermal conductivity cell detector (TCD), the carrier gas was argon, and the flow rate was 15 ml / min; a hydrogen flame detector (FID), the carrier gas was hydrogen and nitrogen, and the flow rates were 30 ml / min and 50 ml / min respectively; the column box starting temperature was 80°C, the temperature was programmed to 180°C, and the calibration normalization method was used for quantification.

[0068] The catalyst is reduced before use, the reduction temperature is 500-700°C, the reduction method is constant temperature reduction, and the hydrogen concentration is 10-40%.

[0069] The reduction conditions and performance evaluation conditions of the catalysts prepared in the following examples and comparative examples are the same.

[0070] The calculation formulas for methane conversion rate and hydrogen production rate are as follows:

[0071] Instantaneous conversion of methane:

[0072] Average methane conversion rate:

[0073] in, Represents the mass concentration of hydrogen in the reaction product.

[0074] Example 1

[0075] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0076] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring at 80° C. to obtain a first mixed solution; weighing 5 g PEG-2000 and 8 g ammonium citrate, adding them to 100 ml of deionized water, and stirring them evenly to obtain a PEG-2000-ammonium citrate composite dispersant solution; adding the PEG-2000-ammonium citrate composite dispersant solution to the first mixed solution, stirring at a constant temperature of 80° C. for 120 min, and stirring at a speed of 150 r / min, to obtain a second mixed solution;

[0077] (2) Weighing 4 g of maleic acid and 10 g of ammonium chloride, adding them to 200 ml of deionized water, and stirring them at 80° C. at a speed of 150 r / min for 120 min to obtain a maleic acid-ammonium chloride composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 80° C. with stirring at a dropping speed of 10 ml / min to obtain a third mixed solution;

[0078] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; adding the third mixed solution and the aqueous solution containing ammonium ions into a flask at 80° C. in parallel, stirring the mixture to obtain a fourth mixed solution;

[0079] (4) The fourth mixed solution is evaporated at 80°C at a speed of 150 r / min, and when the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110°C. After drying, it is roasted in a muffle furnace for 5 hours, the roasting temperature is 800°C, and the roasting atmosphere is air. After cooling, it is crushed with a mortar, and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0080] Calculated by the mass of metal oxides, the nickel content of the catalyst is 44%, the lanthanum content is 13%, the copper content is 8% and the aluminum content is 35%.

[0081] The catalyst prepared in this example was subjected to SEM-EDS analysis, and the results were as follows: Figure 1 and Figure 3 shown. Figure 1 This is the SEM image of the catalyst prepared in this example. Figure 3This is a mapping diagram of the main active components in the catalyst prepared in this embodiment. It can be seen that the main active components in the surface layer of the catalyst prepared in this embodiment are evenly distributed without obvious agglomeration, and the main active components have good dispersion.

[0082] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 47.3%, 2.9 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly. Figure 2 This is the SEM image of carbon black produced by the catalyst prepared in this example.

[0083] Example 2

[0084] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0085] (1) adding 3.2 g nickel nitrate as a precursor of the main active component, 1.2 g lanthanum nitrate and 0.7 g chromium nitrate as precursors of the auxiliary active component, and 2.4 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 75° C. to obtain a first mixed solution; weighing 5 g fatty alcohol polyoxyethylene ether AEO-7 and 10 g polystyrene maleate, adding them to 100 ml of deionized water, and stirring them evenly to obtain a composite dispersant solution; adding the composite dispersant solution to the first mixed solution, stirring at a constant temperature of 75° C. for 100 min, and stirring at a speed of 120 r / min to obtain a second mixed solution;

[0086] (2) weighing 5 g of tartaric acid and 12 g of ammonium chloride and adding them to 200 ml of deionized water, stirring at a constant temperature of 120 r / min at 75° C. for 100 min to obtain a tartaric acid-ammonium chloride composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 75° C. with stirring at a dropping speed of 9 ml / min to obtain a third mixed solution;

[0087] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring at a constant temperature of 75° C. and a speed of 120 r / min for 60 min to obtain an aqueous solution containing ammonium ions; at 75° C., the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel, and stirred evenly to obtain a fourth mixed solution;

[0088] (4) The fourth mixed solution is evaporated at 80° C. and a speed of 120 r / min with stirring. When the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 350 r / min and the temperature is increased to 90° C., and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 h, and the drying temperature is set to 110° C. After drying, it is roasted in a muffle furnace for 5 h, the roasting temperature is 800° C., the roasting atmosphere is air, and after cooling, it is crushed with a mortar and then sieved with a 60-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0089] Calculated by the mass of metal oxides, the nickel content of the catalyst is 43%, the lanthanum content is 16%, the chromium content is 10%, and the aluminum content is 31%.

[0090] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 46.8%, 2.8 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0091] Example 3

[0092] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0093] (1) adding 3.3 g of nickel nitrate as a precursor of the main active component, 1.1 g of molybdenum nitrate, 0.8 g of copper nitrate, 0.6 g of cerium nitrate as precursors of the auxiliary active component, and 2.5 g of aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 70° C. to obtain a first mixed solution; weighing 12 g of alkylphenol polyoxyethylene ether OP-10 and 20 g of hexadecyltrimethylammonium bromide, adding them to 100 ml of deionized water, and stirring them evenly to obtain a composite dispersant solution; adding the composite dispersant solution to the first mixed solution, stirring at a constant temperature of 70° C. for 90 min, and stirring at a speed of 110 r / min to obtain a second mixed solution;

[0094] (2) weighing 5 g of malic acid and 10 g of ammonium nitrate and adding them to 200 ml of deionized water, stirring at 70° C. at a speed of 110 r / min for 90 min to obtain a malic acid-ammonium nitrate composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 70° C. with stirring at a dropping speed of 8 ml / min to obtain a third mixed solution;

[0095] (3) Weighing 10 g of ammonium carbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 110 r / min at 70° C. for 60 min to obtain an aqueous solution containing ammonium ions; adding the third mixed solution and the aqueous solution containing ammonium ions into a flask at 70° C. in parallel, stirring the mixture to obtain a fourth mixed solution;

[0096] (4) The fourth mixed solution is stirred and evaporated at 70° C. and a speed of 110 r / min. When the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 300 r / min and the temperature is increased to 100° C., and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110° C. After drying, it is roasted in a muffle furnace for 5 hours, the roasting temperature is 800° C., and the roasting atmosphere is air. After cooling, it is crushed with a mortar and then sieved with a 100-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0097] Calculated by the mass of metal oxides, the nickel content of the catalyst is 40%, the molybdenum content is 13%, the copper content is 10%, the cerium content is 7%, and the aluminum content is 30%.

[0098] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 45.9%, 2.76 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0099] Example 4

[0100] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0101] (1) adding 3.4 g of cobalt nitrate as a precursor of the main active component, 0.7 g of copper nitrate, 0.5 g of chromium nitrate, and 0.6 g of cerium nitrate as precursors of the auxiliary active component, and 2.6 g of magnesium nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 65° C. to obtain a first mixed solution; weighing 15 g of fatty acid polyoxyethylene ester LAE-9 and 30 g of sodium laurate, adding them to 100 ml of deionized water, and stirring them evenly to obtain a composite dispersant solution; adding the composite dispersant solution to the first mixed solution, stirring at a constant temperature of 65° C. for 80 min, and stirring at a speed of 100 r / min, to obtain a second mixed solution;

[0102] (2) weighing 5 g of citric acid and 10 g of ammonium nitrate and adding them to 200 ml of deionized water, stirring at a constant temperature of 100 r / min at 65° C. for 80 min to obtain a citric acid-ammonium nitrate composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 65° C. with stirring at a dropping speed of 10 ml / min to obtain a third mixed solution;

[0103] (3) Weighing 10 g of ammonium carbonate and adding it to 500 ml of deionized water, stirring at a constant temperature of 100 r / min at 65° C. for 60 min to obtain an aqueous solution containing ammonium ions; at 65° C., the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel, and stirred evenly to obtain a fourth mixed solution;

[0104] (4) The fourth mixed solution is evaporated at 65° C. and a speed of 100 r / min. When the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 300 r / min and the temperature is increased to 100° C., and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 h, and the drying temperature is set to 110° C. After drying, it is roasted in a muffle furnace for 5 h, the roasting temperature is 800° C., and the roasting atmosphere is air. After cooling, it is crushed with a mortar and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0105] Calculated by the mass of metal oxides, the catalyst contains 44% cobalt, 9% copper, 6% chromium, 8% cerium and 33% magnesium.

[0106] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 44.8%, 2.85 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0107] Example 5

[0108] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0109] (1) adding 3.3 g of cobalt nitrate as a precursor of the main active component, 0.6 g of copper nitrate, 0.4 g of cerium nitrate, 0.5 g of lanthanum nitrate as precursors of the auxiliary active component, and 2.9 g of magnesium nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 85° C. to obtain a first mixed solution; weighing 30 g of polyoxyethylene alkylamine AMIET-105 and 65 g of polyvinyl alcohol (molecular weight 25,000 to 35,000) and adding them to 100 ml of deionized water, stirring them evenly to obtain a polyoxyethylene alkylamine-polyvinyl alcohol composite dispersant solution; adding the polyoxyethylene alkylamine-polyvinyl alcohol composite dispersant solution to the first mixed solution, stirring at a constant temperature of 85° C. for 150 min, and stirring at a speed of 160 r / min to obtain a second mixed solution;

[0110] (2) weighing 5 g of alginic acid and 10 g of ammonium chloride and adding them to 200 ml of deionized water, stirring them at 85° C. at a speed of 150 r / min for 150 min to obtain an alginate-ammonium chloride composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 85° C. with stirring at a dropping speed of 9 ml / min to obtain a third mixed solution;

[0111] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring at a constant temperature of 85° C. and a speed of 160 r / min for 60 min to obtain an aqueous solution containing ammonium ions; at 85° C., the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel, and stirred evenly to obtain a fourth mixed solution;

[0112] (4) The fourth mixed solution is evaporated at 85° C. and a speed of 160 r / min with stirring. When the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 350 r / min and the temperature is increased to 100° C., and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 h, and the drying temperature is set to 110° C. After drying, it is roasted in a muffle furnace for 5 h, the roasting temperature is 800° C., and the roasting atmosphere is air. After cooling, it is crushed with a mortar and then sieved with a 60-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0113] Calculated by the mass of metal oxides, the catalyst contains 43% cobalt, 8% copper, 5% cerium, 6% lanthanum and 38% magnesium.

[0114] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 45.2%, 2.84 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0115] Example 6

[0116] This embodiment provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0117] (1) adding 3.2g nickel nitrate and 1.4g cobalt nitrate as precursors of the main active component, 0.4g copper nitrate, 0.5g cerium nitrate, 0.3g lanthanum nitrate, 0.8g iron nitrate, 0.9g chromium nitrate as precursors of the auxiliary active component, and 2.7g aluminum nitrate as a precursor of the carrier to 200ml deionized water, and stirring them at 80°C to obtain a first mixed solution; weighing 20g polyoxyethylene lauryl ether and 28g sodium dodecylbenzene sulfonate, adding them to 100ml deionized water, and stirring them evenly to obtain a polyoxyethylene lauryl ether-sodium dodecylbenzene sulfonate composite dispersant solution; adding the polyoxyethylene lauryl ether-sodium dodecylbenzene sulfonate composite dispersant solution to the first mixed solution, stirring at a constant temperature of 80°C for 120min, and stirring at a speed of 150r / min to obtain a second mixed solution;

[0118] (2) Weighing 4 g of glycine and 11 g of ammonium nitrate, adding them to 200 ml of deionized water, and stirring them at 80° C. at a speed of 150 r / min for 120 min to obtain a glycine-ammonium nitrate composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 80° C. with stirring at a dropping speed of 10 ml / min to obtain a third mixed solution;

[0119] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; adding the third mixed solution and the aqueous solution containing ammonium ions into a flask at 80° C. in parallel, stirring the mixture to obtain a fourth mixed solution;

[0120] (4) The fourth mixed solution is evaporated at 90° C. and 300 r / min with stirring. When the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 500 r / min and the temperature is increased to 110° C., and the evaporation is continued until a fluffy material is formed; the fluffy material is then placed in an electric constant temperature blast drying oven and dried for 12 h, and the drying temperature is set to 110° C. After drying, it is calcined in a muffle furnace for 5 h, the calcination temperature is 800° C., the calcination atmosphere is air, and after cooling, it is crushed with a mortar and then sieved with a 100-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0121] Calculated by the mass of metal oxides, the catalyst contains 31% nickel, 14% cobalt, 4% copper, 5% cerium, 3% lanthanum, 8% iron, 9% chromium and 26% aluminum.

[0122] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 44.5%, 2.74 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0123] Comparative Example 1

[0124] This comparative example provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0125] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 80° C. to obtain a first mixed solution; weighing 5 g PEG-2000 and 8 g ammonium citrate, adding them to 100 ml of deionized water, and stirring them evenly to obtain a composite dispersant solution; adding the composite dispersant solution to the first mixed solution, stirring at a constant temperature of 80° C. for 120 min, and stirring at a speed of 150 r / min, to obtain a second mixed solution;

[0126] (2) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; adding the second mixed solution and the aqueous solution containing ammonium ions into a flask at 80° C. in parallel, stirring the mixture to obtain a third mixed solution;

[0127] (3) The third mixed solution is evaporated at 80° C. and 150 r / min with stirring. When the third mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100° C., and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 h, and the drying temperature is set to 110° C. After drying, it is roasted in a muffle furnace for 5 h, the roasting temperature is 800° C., the roasting atmosphere is air, and after cooling, it is crushed with a mortar and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0128] Calculated by the mass of metal oxides, the nickel content of the catalyst is 43%, the lanthanum content is 11%, the copper content is 7% and the aluminum content is 39%.

[0129] The catalyst prepared in this comparative example was evaluated for its catalytic performance. The results showed that the average conversion rate of methane reached 42.9%, 2.20 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0130] Comparative Example 2

[0131] This comparative example provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0132] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them thoroughly at 80° C. to obtain a first mixed solution;

[0133] (2) Weighing 4 g of maleic acid and 10 g of ammonium chloride, adding them to 200 ml of deionized water, and stirring them at 80° C. at a speed of 150 r / min for 120 min to obtain a maleic acid-ammonium chloride composite complexing agent solution; adding the first mixed solution dropwise to the composite complexing agent solution at 80° C. with stirring at a dropping speed of 10 ml / min to obtain a second mixed solution;

[0134] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; at 80° C., the second mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel, and stirred evenly to obtain a third mixed solution;

[0135] (4) The third mixed solution is evaporated at 80°C at a speed of 150 r / min, and when the third mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110°C. After drying, it is roasted in a muffle furnace for 5 hours, the roasting temperature is 800°C, and the roasting atmosphere is air. After cooling, it is crushed with a mortar, and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0136] Calculated by the mass of metal oxides, the nickel content of the catalyst is 39%, the lanthanum content is 7%, the copper content is 10%, and the aluminum content is 44%.

[0137] The catalyst prepared in this comparative example was evaluated for its catalytic performance. The results showed that the average conversion rate of methane reached 41.6%, 2.14 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0138] Comparative Example 3

[0139] This comparative example provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0140] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them thoroughly at 80° C. to obtain a first mixed solution;

[0141] (2) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; at 80° C., the first mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel, and stirred evenly to obtain a second mixed solution;

[0142] (3) The second mixed solution is evaporated at 80°C at a speed of 150 r / min, and when the second mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110°C. After drying, it is calcined in a muffle furnace for 5 hours, the calcination temperature is 800°C, and the calcination atmosphere is air. After cooling, it is crushed with a mortar, and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0143] Calculated by the mass of metal oxides, the nickel content of the catalyst is 37%, the lanthanum content is 6%, the copper content is 11% and the aluminum content is 46%.

[0144] The catalyst prepared in this comparative example was subjected to SEM-EDS analysis. Figure 4 This is a mapping diagram of the active components in the catalyst prepared in this comparative example. Figure 4 It can be seen that in this comparative example, the composite dispersant and ammonium salt composite complexing agent are not added, and the main active component nickel of the synthesized catalyst is easy to agglomerate and has poor dispersibility.

[0145] The catalyst prepared in this comparative example was evaluated for its catalytic performance. The results showed that the average conversion rate of methane reached 40.9%, 2.08 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0146] Comparative Example 4

[0147] This comparative example provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0148] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring them at 80° C. to obtain a first mixed solution; weighing 13 g PEG-2000, adding it to 100 ml of deionized water, and stirring it evenly to obtain a PEG-2000 solution; adding the PEG-2000 solution to the first mixed solution, and stirring at a constant temperature of 80° C. for 120 min at a stirring speed of 150 r / min to obtain a second mixed solution;

[0149] (2) Weighing 4 g of maleic acid and 10 g of ammonium chloride, adding them to 200 ml of deionized water, and stirring them at 80° C. at a speed of 150 r / min for 120 min to obtain a maleic acid-ammonium chloride composite complexing agent solution; adding the second mixed solution dropwise to the composite complexing agent solution at 80° C. with stirring at a dropping speed of 10 ml / min to obtain a third mixed solution;

[0150] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; adding the third mixed solution and the aqueous solution containing ammonium ions into a flask at 80° C. in parallel, stirring the mixture to obtain a fourth mixed solution;

[0151] (4) The fourth mixed solution is evaporated at 80°C at a speed of 150 r / min, and when the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110°C. After drying, it is roasted in a muffle furnace for 5 hours, the roasting temperature is 800°C, and the roasting atmosphere is air. After cooling, it is crushed with a mortar, and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0152] Calculated in terms of metal oxide content, the catalyst contains 42% nickel, 8% lanthanum, 11% copper and 39% aluminum.

[0153] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 43.5%, 2.24 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0154] Comparative Example 5

[0155] This comparative example provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and the preparation method of the catalyst comprises the following steps:

[0156] (1) adding 3.4 g nickel nitrate as a precursor of the main active component, 1.0 g lanthanum nitrate and 0.6 g copper nitrate as precursors of the auxiliary active component, and 2.6 g aluminum nitrate as a precursor of the carrier to 200 ml of deionized water, and stirring at 80° C. to obtain a first mixed solution; weighing 5 g PEG-2000 and 8 g ammonium citrate, adding them to 100 ml of deionized water, and stirring them evenly to obtain a PEG-2000-ammonium citrate composite dispersant solution; adding the PEG-2000-ammonium citrate composite dispersant solution to the first mixed solution, stirring at a constant temperature of 80° C. for 120 min, and stirring at a speed of 150 r / min, to obtain a second mixed solution;

[0157] (2) weighing 14 g of maleic acid and adding it to 200 ml of deionized water, stirring the mixture at 80° C. at a speed of 150 r / min for 120 min to obtain a maleic acid solution; adding the second mixed solution dropwise to the maleic acid solution at 80° C. with stirring at a dropping speed of 10 ml / min to obtain a third mixed solution;

[0158] (3) Weighing 10 g of ammonium bicarbonate and adding it to 500 ml of deionized water, stirring the mixture at a constant temperature of 80° C. and a speed of 150 r / min for 60 min to obtain an aqueous solution containing ammonium ions; adding the third mixed solution and the aqueous solution containing ammonium ions into a flask at 80° C. in parallel, stirring the mixture to obtain a fourth mixed solution;

[0159] (4) The fourth mixed solution is evaporated at 80°C at a speed of 150 r / min, and when the fourth mixed solution is transformed into a viscous wet glue, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation is continued until a fluffy material is formed; then the fluffy material is placed in an electric constant temperature blast drying oven and dried for 12 hours, and the drying temperature is set to 110°C. After drying, it is roasted in a muffle furnace for 5 hours, the roasting temperature is 800°C, and the roasting atmosphere is air. After cooling, it is crushed with a mortar, and then sieved with an 80-mesh screen to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black.

[0160] Calculated by the mass of metal oxides, the nickel content of the catalyst is 41%, the lanthanum content is 9%, the copper content is 12% and the aluminum content is 38%.

[0161] The catalyst prepared in this example was evaluated for its performance. The results showed that the average conversion rate of methane reached 43.7%, 2.28 g of carbon black was obtained, the reaction time was 10 h, and the catalyst activity did not decrease significantly.

[0162] By comparing Comparative Examples 1 to 5 with Example 1, it can be seen that the main active component in the surface layer of the catalyst prepared in Example 1 is evenly distributed, there is no obvious agglomeration, and the main active component has good dispersibility. However, Comparative Example 3 does not use a compounded dispersant and ammonium salt complexing agent, and the main active component nickel of the synthesized catalyst is easy to agglomerate and has poor dispersibility. Moreover, under the same catalytic performance evaluation conditions, the average methane conversion rate of Example 1 reaches 47.3%, and 2.9g of carbon black is obtained; while the average methane conversion rate and carbon black output of Comparative Examples 1 to 5 are significantly lower than those of Example 1.

[0163] In summary, the present invention adopts a sol-gel method to synthesize a catalyst for catalytic cracking of methane to produce hydrogen and carbon black. Through the synergistic effect of a specific compound dispersant and an ammonium salt composite complexing agent, the prepared catalyst has the advantages of good active component dispersion effect, high methane conversion rate, strong carbon black production ability, good stability, etc. The preparation process of the catalyst is simple and the cost is low. The catalyst is used in the reaction of catalytic cracking of methane to produce hydrogen and carbon black, and a higher methane conversion rate and a higher yield of hydrogen and carbon black can be obtained under the conditions of a lower reaction temperature and a higher space velocity.

Claims

1. A method for preparing a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, comprising the following steps: (1) mixing a precursor of a main active component of the catalyst, a precursor of a co-active component and a precursor of a carrier in water to obtain a first mixed solution; Adding a dispersant to the first mixed solution and stirring evenly to obtain a second mixed solution; (2) adding the second mixed solution dropwise to the complexing agent aqueous solution and stirring evenly to obtain a third mixed solution; (3) mixing the third mixed solution with an aqueous solution containing ammonium ions, and stirring them uniformly to obtain a fourth mixed solution; (4) evaporating the fourth mixed solution to dryness to obtain a fluffy substance, drying and roasting the fluffy substance, and then crushing and sieving the fluffy substance to obtain the catalyst for catalytic cracking of methane to produce hydrogen and carbon black; Wherein, the main active component includes one or a combination of nickel, cobalt, nickel oxide and cobalt oxide; The auxiliary active component includes one or more metals and / or metal oxides selected from Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La; The carrier includes one or a combination of MgO, γ-Al2O3, SiO2, TiO2, ZrO2, MgO-Al2O3 composite oxide, MgO-SiO2 composite oxide, graphite and perovskite.

2. The preparation method according to claim 1, wherein Taking the total mass of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black as 100%, it comprises: 10% to 50% of the main active component calculated as oxide, 0.1% to 30% of the auxiliary active component calculated as oxide and the balance of the carrier.

3. The preparation method according to claim 1, wherein In step (1), the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier respectively include soluble salt compounds of the main active component, the auxiliary active component and the carrier.

4. The preparation method according to claim 1, wherein In step (1), the dispersant comprises a combination of a first dispersant and a second dispersant, wherein the first dispersant comprises one or a combination of polyethylene glycol, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester and polyoxyethylene alkylamine; and the second dispersant comprises one or a combination of ammonium citrate, polystyrene maleate, hexadecyltrimethylammonium bromide, sodium laurate, polyvinyl alcohol and sodium dodecylbenzene sulfonate. Preferably, the mass ratio of the first dispersant to the second dispersant is 1:(1-2.5); Preferably, the dispersant comprises a composition of polyethylene glycol and ammonium citrate, a composition of fatty alcohol polyoxyethylene ether and polystyrene maleate, a composition of alkylphenol polyoxyethylene ether and cetyltrimethylammonium bromide, a composition of fatty acid polyoxyethylene ester and sodium laurate, a composition of polyoxyethylene alkylamine and polyvinyl alcohol, or a composition of polyoxyethylene lauryl ether and sodium dodecylbenzene sulfonate; Preferably, in step (1), the amount of the dispersant added is 1% to 30% of the total mass of the second mixed solution.

5. The preparation method according to claim 1, wherein In step (2), the complexing agent includes an ammonium salt composite complexing agent formed by a combination of one or more of maleic acid, tartaric acid, malic acid, glycine, alginic acid, pyrophosphoric acid and citric acid and an ammonium salt; Preferably, in step (2), the mass ratio of the total amount of the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier in the second mixed solution to the ammonium salt complexing agent in the complexing agent aqueous solution is (7-11):(13-18).

6. The preparation method according to claim 1, wherein In step (3), the mass ratio of the ammonium ions in the aqueous solution containing ammonium ions to the total amount of the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier in the second mixed solution is (2-4):(7-11); Preferably, in step (3), the aqueous solution containing ammonium ions comprises an aqueous solution of ammonium salts and / or aqueous ammonia; Preferably, in step (3), the ammonium salt comprises one or a combination of ammonium bicarbonate, ammonium carbonate and ammonium nitrate; Preferably, in step (3), the third mixed solution and the aqueous solution containing ammonium ions are mixed by flowing into a container.

7. The preparation method according to claim 1, wherein In step (4), the process of evaporating the fourth mixed solution specifically includes: evaporating the fourth mixed solution at 65-90° C. at a speed of 100-300 r / min, and when the fourth mixed solution is transformed into a viscous wet glue, increasing the stirring speed to 300-500 r / min and the temperature to 90-110° C., and continuing to evaporate until the fluffy material is formed.

8. A catalyst for catalytic cracking of methane to produce hydrogen and carbon black, which is prepared by the preparation method of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to any one of claims 1 to 7; the general formula of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black is shown in Formula I: aX·bY·(100-ab)M Formula I, in, X represents the main active component, Y represents the auxiliary active component, and M represents the carrier; a, b represent the mass percentage of components X and Y respectively, and 10≤a≤50, 0.1≤b≤30; the main active component includes one or more of nickel, cobalt, nickel oxide and cobalt oxide; the auxiliary active component includes one or more of metals and / or metal oxides selected from Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La; the carrier includes one or more of MgO, γ-Al2O3, SiO2, TiO2, ZrO2, MgO-Al2O3 composite oxide, MgO-SiO2 composite oxide, graphite and perovskite.

9. The catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to claim 8, wherein: The auxiliary active component includes one or more metals and / or metal oxides selected from the group consisting of Fe, Zn, Cu, Ce and La.

10. The catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to claim 8, wherein: The carrier includes one or a combination of γ-Al2O3, MgO, perovskite and magnesium aluminum spinel.

11. The catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to claim 8, wherein: In formula I, 40≤a≤45, 15≤b≤30.

12. Use of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to any one of claims 8 to 11 in catalytic cracking of methane to produce hydrogen and carbon black.

13. The use according to claim 12, wherein: The application includes: using a fixed bed reactor, under the action of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black, catalytic cracking of raw gas including methane is carried out to obtain hydrogen and carbon black; wherein, based on the loading amount of the catalyst being 0.5g, the feed flow rate of the raw gas is 10-400ml / min; the reaction temperature of the catalytic cracking is 400-900°C, and the reaction pressure is normal pressure; Preferably, the feed gas comprises pure methane and / or other methane-rich gas; Preferably, based on the loading amount of the catalyst being 0.5 g, the feed flow rate of the raw gas is 50 to 200 ml / min; Preferably, the reaction temperature of the catalytic cracking is 500-800°C.

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