A catalyst for catalytic cracking of methane to produce hydrogen and carbon black, and a preparation method and application thereof

Abstract

The application provides a catalyst for hydrogen and carbon black production by catalytic cracking of methane, a preparation method and application thereof. The preparation method comprises the following steps: uniformly mixing a main active component, an auxiliary active component and a precursor of a carrier of the catalyst in water, adding a dispersing agent, dropping the obtained mixed solution into an aqueous complexing agent solution, then mixing with an aqueous solution containing ammonium ions, and after evaporation, drying, calcination, crushing and sieving, the catalyst for hydrogen and carbon black production by catalytic cracking of methane is obtained. The catalyst provided by the application is prepared by the preparation method. The catalyst 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 present application relates to a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, as well as a preparation method and application thereof, and belongs to the technical field of catalysts for catalytic cracking of methane. BACKGROUND

[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 a kind of efficient and clean secondary energy, is considered to be one of the most promising alternative energy and clean fuel. At present, the main methods for industrial hydrogen production include coal gasification hydrogen production, methane partial oxidation hydrogen production, methane steam reforming hydrogen production, biomass hydrogen production and water electrolysis hydrogen production. The coal hydrogen production technology has problems such as relatively backward process and low hydrogen production efficiency. Biomass hydrogen production is an industrial technology that meets the sustainable development strategy, but the catalyst activity is low and the reaction process fluctuates. The water electrolysis hydrogen production process is simple, pollution-free and green, but the reaction process has high energy consumption and high production cost, causing certain resource waste, so the application of water electrolysis hydrogen production is limited.

[0003] Natural gas (main component is CH4) 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. This process is simple, has low energy consumption and no environmental pollution. In addition, the carbon materials (carbon nanotubes, carbon black, etc.) generated in the MCD reaction process have excellent physical and chemical properties and are widely used in many fields, having high economic value.

[0004] At present, the catalysts for natural gas cracking to produce hydrogen mainly include metal-supported catalysts and carbon-based catalysts. The methane conversion rate of metal catalysts is low, the space velocity is not high, the hydrogen production rate is low, and the added value of carbon products is not high. The carbon-based catalyst reaction 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 catalytic cracking of methane to produce hydrogen using activated carbon as a catalyst. The catalyst has high activity for catalytic cracking of methane to produce hydrogen, and prolongs the deactivation time of the activated carbon catalyst. However, the carbon product produced by the catalyst has many metal impurities and types of carbon products, increasing 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 shows good catalytic performance for high-temperature methane cracking. However, the catalyst requires high-temperature conditions and has high energy consumption in the reaction process.

[0007] CN110227462A discloses a catalyst for directly catalytic cracking of methane to produce hydrogen and a preparation method thereof. The catalyst takes MO / CNFs as a carrier to load active components Ni, wherein the weight parts of each component are: M element 10-50, MO y 5-70, CNFs 2-45; MO y is one of SiO2, ZrO2, TiO2, Ce (1-x) Zr x O2. The preparation method of the catalyst is to add MO y and pretreated CNFs into a nickel salt aqueous solution, then add lye to adjust the pH value to 6-8, stir and stand, and the obtained precipitate is filtered, washed and dried to obtain the catalyst. The catalyst has high methane conversion rate, strong carbon deposition resistance and good stability.

[0008] CN110683511A discloses a "catalytic oxygen carrier" of Ni x Fe 3-X -Ca2Fe y Al 2-y O5, and a method for catalytically cracking methane to produce hydrogen and reducing CO2 synergistically. The catalytic oxygen carrier can respectively regulate the methane catalytic cracking to produce hydrogen reaction and the CO2 reduction reaction based on the chemical chain cycle. The specific steps of the method are as follows: (1) methane cracking stage, catalytic cracking of methane under the action of the catalytic oxygen carrier to realize high methane conversion rate and high hydrogen selectivity, and obtain byproduct nanocarbon; (2) CO2 reduction stage, realize high CO2 conversion rate and high CO selectivity under the condition of reducing the catalytic oxygen carrier and nanocarbon, and realize regeneration of the catalytic oxygen carrier. The method realizes continuous and efficient production of high-purity H2 and CO2 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 takes Ni and Fe as active components, CeO2 as a catalyst promoter, and fly ash as a carrier. The Ni-Fe-CeO2 fly ash catalyst is prepared by the method of pre-deposition and post-impregnation. The catalyst has high specific surface area and dispersity. The addition of CeO2 can significantly improve the activity of the catalyst in the reaction of catalytic cracking of methane to produce hydrogen, and the catalyst has good cycle performance.

[0010] However, there is still a lack of efficient method for catalytic cracking of methane to produce hydrogen and carbon black in the prior art. SUMMARY

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

[0012] To achieve the above-mentioned purpose, the present application provides a preparation method of a catalyst for methane catalytic cracking to produce hydrogen and carbon black, comprising the following steps:

[0013] (1) uniformly mixing a precursor of a main active component, a precursor of an auxiliary active component and a precursor of a carrier in water to obtain a first mixed solution; adding a dispersing agent to the first mixed solution, and uniformly stirring to obtain a second mixed solution;

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

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

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

[0017] The main active component comprises one or a combination of several of nickel, cobalt, nickel oxide and cobalt oxide.

[0018] The auxiliary active component comprises one or several of Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La metal and / or metal oxide.

[0019] The carrier comprises one or a combination of several of MgO, γ-Al2O3, SiO2, TiO2, ZrO2, MgO-Al2O3 composite oxide, MgO-SiO2 composite oxide, graphite and perovskite.

[0020] In the above preparation method, preferably, the catalyst for methane catalytic cracking to produce hydrogen and carbon black comprises, based on the total mass of 100%, 10-50% of the main active component in terms of oxide, 0.1-30% of the auxiliary active component in terms of oxide and the balance of the carrier.

[0021] In the above preparation method, preferably, in step (1), the precursors of the main active component, the precursors of the auxiliary active component and the precursors of the carrier respectively include soluble salt compounds of the main active component, the auxiliary active component and the carrier, such as but not limited to nitrate, chloride and the like. The precursors of the carrier can also include phosphate and / or sulfate and the like.

[0022] In the above preparation method, preferably, in step (1), the dispersant includes a combination of a first dispersant and a second dispersant, the first dispersant includes a combination of one or more of polyethylene glycol, fatty alcohol polyoxyethylene ether, alkyl phenol polyoxyethylene ether, fatty acid polyoxyethylene ester and polyoxyethylene alkylamine and the like; the second dispersant includes a combination of one or more of ammonium citrate, polystyrene maleate, cetyltrimethylammonium bromide, sodium laurate, polyvinyl alcohol and sodium dodecylbenzenesulfonate and the like. 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 combination of polyethylene glycol (preferably PEG-2000) and ammonium citrate, a combination of fatty alcohol polyoxyethylene ether and polystyrene maleate, a combination of alkyl phenol polyoxyethylene ether and cetyltrimethylammonium bromide, a combination of fatty acid polyoxyethylene ester and sodium laurate, a combination of polyoxyethylene alkylamine and polyvinyl alcohol, or a combination of polyoxyethylene lauryl ether and sodium dodecylbenzenesulfonate.

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

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

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

[0026] In the above preparation method, preferably, in step (2), the mass ratio of the total amount of the precursors of the main active component, the precursors of the auxiliary active component and the precursors 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).

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

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

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

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

[0031] In the above preparation method, preferably, in step (3), the aqueous solution containing ammonium ions comprises an aqueous solution of ammonium salt and / or ammonia water. More preferably, the aqueous solution of ammonium salt is prepared by adding ammonium salt into water, constant temperature stirring at 50-500 r / min for 50-200 min at 50-90℃. More preferably, the aqueous solution of ammonium salt is prepared by adding ammonium salt into water, constant temperature stirring at 100-300 r / min for 60-180 min at 70-80℃. The concentration of the aqueous solution of ammonium salt and the concentration of the ammonia water can be routinely adjusted by those skilled in the art, as long as the mass ratio relationship of 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 is met and the reaction proceeds smoothly.

[0032] In the above preparation method, preferably, in step (3), the ammonium salt comprises one or a combination of several 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 parallel flow into a container.

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

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

[0036] In the above preparation method, preferably, in step (4), the drying temperature is 80-150℃ and the time is 1-24 h.

[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℃ and the time is 1-10 h, and the protective atmosphere comprises one or a combination of several of air, nitrogen, argon, helium, neon, etc. More preferably, the calcination temperature is 650-800℃ and the time is 2-6 h.

[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 sieving uses a 60-120 mesh sieve, more preferably, uses an 80-120 mesh sieve.

[0040] In the above preparation method, preferably, the promoter includes one or more of metals and / or metal oxides of Fe, Zn, Cu, Ce and La.

[0041] In the above preparation method, preferably, the carrier includes one or more of combinations of γ-Al2O3, MgO, perovskite and magnesium aluminate spinel, etc. Among them, the magnesium aluminate spinel is one of MgO-Al2O3 composite oxides.

[0042] In the above preparation method, preferably, the catalyst for catalytic cracking of methane to produce hydrogen and carbon black includes, based on the total mass of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black being 100%, 40-45% of the main active component in terms of oxides, 15-30% of the promoter in terms of oxides and the balance of the carrier.

[0043] The second aspect of the present application provides a catalyst for catalytic cracking of methane to produce hydrogen and carbon black, which is prepared by the above preparation method of 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-a-b)M formula I,

[0045] Wherein, X represents the main active component, Y represents the promoter, and M represents the carrier; a and b respectively represent the mass percentage of components X and Y, and 10≤a≤50, 0.1≤b≤30; the main active component includes one or more of combinations of nickel, cobalt, nickel oxide and cobalt oxide; the promoter includes one or more of metals and / or metal oxides of Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La; the carrier includes one or more of combinations of MgO, γ-Al2O3, SiO2, TiO2, ZrO2, MgO-Al2O3 composite oxide, MgO-SiO2 composite oxide, graphite and perovskite, etc.

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

[0047] In the catalyst for catalytic cracking of methane to produce hydrogen and carbon black, preferably, the carrier comprises one or a combination of several of γ-Al2O3, MgO, perovskite, and magnesium aluminate spinel, etc. Among them, the magnesium aluminate spinel is one of MgO-Al2O3 composite oxides.

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

[0049] The third aspect of the present application provides the use of the 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 the specific embodiment of the present application, preferably, the use comprises: using a fixed bed reactor, and under the action of the catalyst for catalytic cracking of methane to produce hydrogen and carbon black, catalytically cracking a raw gas comprising methane to obtain hydrogen and carbon black; wherein, based on the loading amount of the catalyst being 0.5g, the feeding flow rate of the raw gas is 10-400ml / min; the reaction temperature of the catalytic cracking is 400-900℃, and the reaction pressure is normal pressure.

[0051] In the use, preferably, the raw gas comprises pure methane and / or other methane-rich gas (for example, natural gas after preliminary desulfurization treatment, or refinery gas, etc.).

[0052] In the use, preferably, based on the loading amount of the catalyst being 0.5g, the feeding flow rate of the raw gas is 50-200ml / min.

[0053] In the use, preferably, the reaction temperature of the catalytic cracking is 500-800℃.

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

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

[0056] (1) The catalyst for catalytic cracking of methane to produce hydrogen and carbon black is synthesized by sol-gel method, and in the preparation process of the catalyst, a compounded dispersant is developed, the solution containing the precursor of the active component is pretreated, and the active groups are dispersed, compared with the single nonionic surfactant, the compounded dispersant can efficiently disperse the main active component and the auxiliary active component into the inert carrier, so that the phenomenon of easy aggregation or uneven dispersion of the metal in the synthesis process is avoided, and the dispersity of the active component is improved.

[0057] (2) In the process of synthesizing the catalyst for catalytic cracking of methane to produce hydrogen and carbon black by sol-gel method, the specific ammonium salt complexing agent is used to form a complex with the precursor of the active component, and the free ions are less, when the hydroxide precipitate is generated, the metal ions (i.e. the active component) are slowly released from the complex, the precipitation process is slowed down, and the ultra-fine hydroxide precipitate can be formed, which is beneficial to generate ultra-fine catalyst powder.

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

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

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

[0061] Figure 3 Mapping image of the main active component in the catalyst prepared in Example 1.

[0062] Figure 4 Mapping image of the main active component in the catalyst prepared in Comparative Example 3. DETAILED DESCRIPTION

[0063] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application will be described in detail as follows, but it cannot be understood as a limitation on the implementable scope of the present application.

[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 performing a methane catalytic cracking reaction in a small quartz tube fixed bed reactor, with a catalyst loading of 0.5 g, a reaction temperature of 500-800°C, a reaction pressure of atmospheric pressure, a reaction time of 10 h, and a flow rate of methane (purity of 99.99 vol%, commercially available) of 50 ml / min. The components of the reaction products were analyzed using an external standard method by means of an HP-7890 gas chromatograph; the chromatographic column was a capillary column HP-PLOT-Q with a size of 30 m x 0.53 mm; two detectors were set, a thermal conductivity cell detector (TCD) with argon as the carrier gas at a flow rate of 15 ml / min, and a hydrogen flame detector (FID) with hydrogen and nitrogen as the carrier gases at flow rates of 30 ml / min and 50 ml / min, respectively; the column oven was programmed to start at 80°C and to increase to 180°C, and the corrected normalization method was used for quantification.

[0068] The catalysts were reduced before use at a reduction temperature of 500-700°C; the reduction method was isothermal reduction; and the hydrogen concentration was 10-40%.

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

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

[0071] Methane instantaneous conversion rate:

[0072] Methane average conversion rate:

[0073] wherein, represents the mass concentration of hydrogen in the reaction products.

[0074] Example 1

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

[0076] (1) Put 3.4 g of nickel nitrate as a precursor of the main active component, 1.0 g of lanthanum nitrate and 0.6 g of copper nitrate as precursors of the auxiliary active component, and 2.6 g of aluminum nitrate as a precursor of the carrier into 200 ml of deionized water, and obtain a first mixed solution by stirring at 80°C; weigh 5 g of PEG-2000 and 8 g of ammonium citrate into 100 ml of deionized water, and obtain a PEG-2000-ammonium citrate complex dispersant solution by stirring uniformly; add the PEG-2000-ammonium citrate complex dispersant solution into the first mixed solution, and obtain a second mixed solution by stirring at 80°C for 120 min at a stirring speed of 150 r / min;

[0077] (2) Weigh 4 g of maleic acid and 10 g of ammonium chloride into 200 ml of deionized water, and obtain a maleic acid-ammonium chloride complex complexing agent solution by stirring at 80°C at a speed of 150 r / min for 120 min; add the second mixed solution into the complex complexing agent solution under the condition of stirring at 80°C, and obtain a third mixed solution by dripping at a dripping speed of 10 ml / min;

[0078] (3) Weigh 10 g of ammonium bicarbonate into 500 ml of deionized water, and obtain an aqueous solution containing ammonium ions by stirring at 80°C at a speed of 150 r / min for 60 min; add the third mixed solution and the aqueous solution containing ammonium ions into a flask under the condition of parallel flow at 80°C, and obtain a fourth mixed solution by stirring uniformly;

[0079] (4) Stir the fourth mixed solution at 80°C at a speed of 150 r / min until it is evaporated to a sticky wet gel; increase the stirring speed to 400 r / min and the temperature to 100°C, and continue to evaporate until a fluffy material is formed; then dry the fluffy material in an electric heating constant temperature air drying oven for 12 h, set the drying temperature to 110°C, dry the fluffy material after the drying is completed in a muffle furnace for 5 h at a calcination temperature of 800°C in an air atmosphere, cool, crush with a mortar, and sieve with an 80-mesh sieve to obtain the catalyst for methane catalytic cracking for hydrogen production and carbon black.

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

[0081] The catalyst prepared in this example is subjected to SEM-EDS analysis, and the results are shown in Figure 1 and Figure 3 . Figure 1 The SEM image of the catalyst prepared in this example. Figure 3The mapping picture of the main active component in the catalyst prepared in the embodiment. It can be seen that the main active component in the catalyst prepared in the embodiment is uniformly distributed in the surface layer, and there is no obvious agglomeration, and the main active component has good dispersity.

[0082] The catalyst prepared in the embodiment is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 47.3%, 2.9g of carbon black is obtained, the reaction time is 10h, and the catalyst activity does not obviously decrease. Figure 2 The SEM picture of the carbon black produced by the catalyst prepared in the embodiment.

[0083] Embodiment 2

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

[0085] (1) 3.2g of nickel nitrate as a precursor of the main active component, 1.2g of lanthanum nitrate and 0.7g of chromium nitrate as precursors of the auxiliary active component, and 2.4g of aluminum nitrate as a precursor of the carrier are added into 200ml of deionized water, and a first mixed solution is obtained by fully stirring at 75°C; 5g of fatty alcohol polyoxyethylene ether AEO-7 and 10g of polystyrene maleate are weighed and added into 100ml of deionized water, and a complex dispersant solution is obtained by fully stirring; the complex dispersant solution is added into the first mixed solution, and a second mixed solution is obtained by stirring at 75°C for 100min at a stirring speed of 120r / min;

[0086] (2) 5g of tartaric acid and 12g of ammonium chloride are weighed and added into 200ml of deionized water, and a tartaric acid-ammonium chloride complex complexing agent solution is obtained by stirring at 75°C at a speed of 120r / min for 100min; the second mixed solution is added dropwise into the complex complexing agent solution under the condition of stirring at 75°C, and a third mixed solution is obtained by dropwise adding at a speed of 9ml / min;

[0087] (3) 10g of ammonium bicarbonate is weighed and added into 500ml of deionized water, and an aqueous solution containing ammonium ions is obtained by stirring at 75°C at a speed of 120r / min for 60min; under the condition of 75°C, the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel flow, and a fourth mixed solution is obtained by stirring uniformly.

[0088] (4) the fourth mixed solution is evaporated at 80°C with stirring at a speed of 120 r / min, when the fourth mixed solution is changed into a wet glue in the form of a sticky substance, 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 substance is formed; then the fluffy substance is placed into an electric heating constant temperature air drying oven for drying for 12 h, the drying temperature is set to 110°C, after the drying is completed, the fluffy substance is calcined in a muffle furnace for 5 h, the calcination temperature is 800°C, the calcination atmosphere is air, after cooling, the fluffy substance is crushed with a mortar and sieved with a 60-mesh screen, and the catalyst for hydrogen production and carbon black production by catalytic cracking of methane is obtained.

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

[0090] The catalyst prepared in this embodiment is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 46.8%, 2.8 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not show obvious decrease.

[0091] Example 3

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

[0093] (1) 3.3 g of nickel nitrate as a precursor of a main active component, 1.1 g of molybdenum nitrate, 0.8 g of copper nitrate, and 0.6 g of cerium nitrate as precursors of auxiliary active components, and 2.5 g of aluminum nitrate as a precursor of a carrier are added into 200 ml of deionized water, and a first mixed solution is obtained by fully stirring at 70°C; 12 g of alkylphenol polyoxyethylene ether OP-10 and 20 g of cetyltrimethylammonium bromide are weighed and added into 100 ml of deionized water, and a complex dispersant solution is obtained by fully stirring; the complex dispersant solution is added into the first mixed solution, and a second mixed solution is obtained by stirring at 70°C for 90 min at a stirring speed of 110 r / min;

[0094] (2) 5 g of malic acid and 10 g of ammonium nitrate are weighed and added into 200 ml of deionized water, and a malic acid-ammonium nitrate complexing agent solution is obtained by stirring at 70°C for 90 min at a stirring speed of 110 r / min; the second mixed solution is added dropwise into the complexing agent solution under the condition of stirring at 70°C, and a third mixed solution is obtained at a dropwise speed of 8 ml / min;

[0095] (3) Weigh 10 g of ammonium carbonate into 500 ml of deionized water, and stir at 110 r / min at 70°C for 60 min to obtain an aqueous solution containing ammonium ions; under the condition of 70°C, the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel flow, and after uniform stirring, a fourth mixed solution is obtained;

[0096] (4) The fourth mixed solution is stirred at 110 r / min at 70°C until it is evaporated to dryness. When the fourth mixed solution is converted into a sticky wet gel, 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 heating constant temperature air drying oven for drying for 12 h, the drying temperature is set to 110°C, after drying, calcination is carried out in a muffle furnace for 5 h, the calcination temperature is 800°C, the calcination atmosphere is air, and after cooling, the material is crushed with a mortar and sieved with a 100 mesh sieve to obtain the catalyst for hydrogen production and carbon black production by catalytic cracking of methane.

[0097] The content of nickel in the catalyst is 40%, the content of molybdenum is 13%, the content of copper is 10%, and the content of cerium is 7%, based on the mass of metal oxides.

[0098] The catalyst prepared in this example is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 45.9%, 2.76 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not decrease significantly.

[0099] Example 4

[0100] The catalyst for hydrogen production and carbon black production by catalytic cracking of methane is prepared by the following steps:

[0101] (1) 3.4 g of cobalt nitrate, 0.7 g of copper nitrate, 0.5 g of chromium nitrate, 0.6 g of cerium nitrate, and 2.6 g of magnesium nitrate are added to 200 ml of deionized water to obtain a first mixed solution; 15 g of fatty acid polyoxyethylene ester LAE-9 and 30 g of sodium laurate are added to 100 ml of deionized water, and stirred uniformly to obtain a complex dispersant solution; the complex dispersant solution is added to the first mixed solution, and stirred at 65°C for 80 min to obtain a second mixed solution;

[0102] (2) take 5 g of citric acid and 10 g of ammonium nitrate and add them to 200 ml of deionized water, and stir at 100 r / min at 65 °C for 80 min to obtain a citric acid-ammonium nitrate complexing agent solution; add the second mixed solution dropwise to the complexing agent solution under stirring at 65 °C, and the dropwise speed is 10 ml / min to obtain a third mixed solution;

[0103] (3) take 10 g of ammonium carbonate and add it to 500 ml of deionized water, and stir at 100 r / min at 65 °C for 60 min to obtain an aqueous solution containing ammonium ions; under the condition of 65 °C, the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel flow, and after stirring uniformly, a fourth mixed solution is obtained;

[0104] (4) the fourth mixed solution is stirred and evaporated at 100 r / min at 65 °C, when the fourth mixed solution is changed into a sticky wet gel, 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 heating constant temperature air drying oven and dried for 12 h, the drying temperature is set to 110 °C, after drying, calcination is carried out in a muffle furnace for 5 h, the calcination temperature is 800 °C, 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 methane catalytic cracking to produce hydrogen and carbon black.

[0105] The content of cobalt in the catalyst is 44% by mass of metal oxide, the content of copper is 9%, the content of chromium is 6%, the content of cerium is 8%, and the content of magnesium is 33%.

[0106] The catalyst prepared in this example is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 44.8%, 2.85 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not show obvious decrease.

[0107] Example 5

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

[0109] (1) Put 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 into 200 ml of deionized water, and obtain a first mixed solution by stirring at 85°C; weigh 30 g of polyoxyethylene alkylamine AMIET-105 and 65 g of polyvinyl alcohol (molecular weight 25000-35000) into 100 ml of deionized water, and obtain a polyoxyethylene alkylamine-polyvinyl alcohol complex dispersant solution by stirring uniformly; add the polyoxyethylene alkylamine-polyvinyl alcohol complex dispersant solution into the first mixed solution, and obtain a second mixed solution by stirring at 85°C for 150 min at a stirring speed of 160 r / min;

[0110] (2) Weigh 5 g of alginic acid and 10 g of ammonium chloride into 200 ml of deionized water, and obtain an alginic acid-ammonium chloride complex complexing agent solution by stirring at 85°C at a speed of 150 r / min for 150 min; add the second mixed solution into the complex complexing agent solution dropwise under the condition of 85°C and stirring, and obtain a third mixed solution at a dropping speed of 9 ml / min;

[0111] (3) Weigh 10 g of ammonium bicarbonate into 500 ml of deionized water, and obtain an aqueous solution containing ammonium ions by stirring at 85°C at a speed of 160 r / min for 60 min; under the condition of 85°C, make the third mixed solution and the aqueous solution containing ammonium ions flow into a flask in parallel, and obtain a fourth mixed solution by stirring uniformly;

[0112] (4) Stir and evaporate the fourth mixed solution at 85°C at a speed of 160 r / min, when the fourth mixed solution is changed into a wet glue in the form of a viscous substance, increase the stirring speed to 350 r / min and the temperature to 100°C, continue to evaporate until a fluffy substance is formed; then put the fluffy substance into an electric heating constant temperature air drying oven to dry for 12 h, set the drying temperature to 110°C, after drying, calcine in a muffle furnace for 5 h, the calcination temperature is 800°C, the calcination atmosphere is air, after cooling, crush with a mortar, and sieve with a 60 mesh sieve, to obtain the catalyst for methane catalytic cracking for hydrogen and carbon black.

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

[0114] The catalyst prepared in this example is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 45.2%, 2.84 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not decrease obviously.

[0115] Example 6

[0116] The embodiment provides a catalyst for hydrogen and carbon black produced by catalytic cracking of methane, and a preparation method of the catalyst, which comprises the following steps:

[0117] (1) 3.2 g of nickel nitrate, 1.4 g of cobalt nitrate, 0.4 g of copper nitrate, 0.5 g of cerium nitrate, 0.3 g of lanthanum nitrate, 0.8 g of iron nitrate, 0.9 g of chromium nitrate, and 2.7 g of aluminum nitrate as precursors of a main active component, an auxiliary active component, and a carrier are added into 200 ml of deionized water, and a first mixed solution is obtained by fully stirring at 80 DEG C; 20 g of polyoxyethylene lauryl ether and 28 g of sodium dodecyl benzene sulfonate are weighed and added into 100 ml of deionized water, and a polyoxyethylene lauryl ether-sodium dodecyl benzene sulfonate compound dispersant solution is obtained by fully stirring; the polyoxyethylene lauryl ether-sodium dodecyl benzene sulfonate compound dispersant solution is added into the first mixed solution, and a second mixed solution is obtained by stirring at 80 DEG C for 120 min at a stirring speed of 150 r / min;

[0118] (2) 4 g of glycine and 11 g of ammonium nitrate are weighed and added into 200 ml of deionized water, and a glycine-ammonium nitrate compound complexing agent solution is obtained by stirring at 80 DEG C for 120 min at a speed of 150 r / min; the second mixed solution is added dropwise into the compound complexing agent solution under the condition of stirring at 80 DEG C, and a third mixed solution is obtained by dropwise adding at a speed of 10 ml / min;

[0119] (3) 10 g of ammonium bicarbonate is weighed and added into 500 ml of deionized water, and an aqueous solution containing ammonium ions is obtained by stirring at 80 DEG C for 60 min at a speed of 150 r / min; the third mixed solution and the aqueous solution containing ammonium ions are introduced into a flask under the condition of parallel flow at 80 DEG C, and a fourth mixed solution is obtained by stirring uniformly;

[0120] (4) the fourth mixed solution is stirred and evaporated at 90 DEG C at a speed of 300 r / min, when the fourth mixed solution is changed into a wet glue in the form of a sticky substance, the stirring speed is increased to 500 r / min and the temperature is increased to 110 DEG C, and the evaporation is continued until a fluffy substance is formed; then the fluffy substance is placed into an electric heating constant temperature air drying oven for drying for 12 h, the drying temperature is set to 110 DEG C, after the drying is completed, the fluffy substance is calcined in a muffle furnace for 5 h, the calcination temperature is 800 DEG C, the calcination atmosphere is air, after cooling, the fluffy substance is crushed with a mortar, and then sieved by using a 100 mesh screen, and the catalyst for hydrogen and carbon black produced by catalytic cracking of methane is obtained.

[0121] The content of nickel in the catalyst is 31% in terms of the mass of metal oxides, the content of cobalt is 14%, the content of copper is 4%, the content of cerium is 5%, the content of lanthanum is 3%, the content of iron is 8%, the content of chromium is 9%, and the content of aluminum is 26%.

[0122] The catalyst prepared in this example was subjected to catalyst performance evaluation. 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 show obvious decline.

[0123] Comparative Example 1

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

[0125] (1) 3.4 g of nickel nitrate, a precursor of the main active component, 1.0 g of lanthanum nitrate, a precursor of the auxiliary active component, 0.6 g of copper nitrate, and 2.6 g of aluminum nitrate, a precursor of the carrier, were added to 200 ml of deionized water, and a first mixed solution was obtained by fully stirring at 80°C; 5 g of PEG-2000 and 8 g of ammonium citrate were weighed and added to 100 ml of deionized water, and a complex dispersant solution was obtained by fully stirring until uniform; the complex dispersant solution was added to the first mixed solution, and a second mixed solution was obtained by constant temperature stirring at 80°C for 120 min at a stirring speed of 150 r / min;

[0126] (2) 10 g of ammonium bicarbonate was weighed and added to 500 ml of deionized water, and an aqueous solution containing ammonium ions was obtained by constant temperature stirring at 80°C at a speed of 150 r / min for 60 min; the second mixed solution and the aqueous solution containing ammonium ions were introduced into a flask under the condition of parallel flow at 80°C, and a third mixed solution was obtained by stirring until uniform;

[0127] (3) The third mixed solution was stirred at 80°C at a speed of 150 r / min until it was evaporated to dryness; when the third mixed solution was changed into a sticky wet gel, the stirring speed was increased to 400 r / min and the temperature was increased to 100°C, and the evaporation was continued until a fluffy material was formed; then the fluffy material was placed in an electric heating constant temperature air drying oven for drying for 12 h, the drying temperature was set to 110°C, after drying was completed, calcination was carried out in a muffle furnace for 5 h, the calcination temperature was 800°C, the calcination atmosphere was air, after cooling, the material was crushed with a mortar, and then sieved with an 80 mesh sieve, to obtain the catalyst for hydrogen production and carbon black production by catalytic cracking of methane.

[0128] The content of nickel in the catalyst was 43% by mass of metal oxide, the content of lanthanum was 11%, the content of copper was 7%, and the content of aluminum was 39%.

[0129] The catalyst prepared in this example was subjected to catalyst performance evaluation. 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 show obvious decline.

[0130] Comparative Example 2

[0131] The present comparative example provides a catalyst for hydrogen and carbon black production by catalytic cracking of methane, and a preparation method of the catalyst, which comprises the following steps:

[0132] (1) 3.4 g of nickel nitrate, a precursor of the main active component, 1.0 g of lanthanum nitrate, a precursor of the auxiliary active component, 0.6 g of copper nitrate, and 2.6 g of aluminum nitrate, a precursor of the carrier, were added into 200 ml of deionized water, and a first mixed solution was obtained by stirring at 80°C;

[0133] (2) 4 g of maleic acid and 10 g of ammonium chloride were weighed and added into 200 ml of deionized water, and a maleic acid-ammonium chloride complexing agent solution was obtained by constant temperature stirring at 80°C and at a speed of 150 r / min for 120 min; the first mixed solution was added dropwise into the complexing agent solution under stirring at 80°C, and a second mixed solution was obtained at a dropwise speed of 10 ml / min;

[0134] (3) 10 g of ammonium bicarbonate was weighed and added into 500 ml of deionized water, and an aqueous solution containing ammonium ions was obtained by constant temperature stirring at 80°C and at a speed of 150 r / min for 60 min; the second mixed solution and the aqueous solution containing ammonium ions were introduced into a flask under the condition of 80°C and parallel flow, and a third mixed solution was obtained after uniform stirring;

[0135] (4) the third mixed solution was evaporated to dryness under stirring at 80°C and at a speed of 150 r / min; when the third mixed solution was changed into a wet gel in the form of a sticky substance, the stirring speed was increased to 400 r / min and the temperature was increased to 100°C, and the evaporation to dryness was continued until a fluffy substance was formed; then the fluffy substance was placed into an electric heating constant temperature air drying oven for drying for 12 h, and the drying temperature was set to 110°C; after the drying was completed, the fluffy substance was calcined in a muffle furnace for 5 h, the calcination temperature was 800°C, the calcination atmosphere was air, and after cooling, the fluffy substance was crushed with a mortar and sieved with a 80-mesh screen to obtain the catalyst for hydrogen and carbon black production by catalytic cracking of methane.

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

[0137] The catalyst prepared in the present comparative example was subjected to catalyst performance evaluation. 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 show obvious decrease.

[0138] Comparative Example 3

[0139] The present comparative example provides a catalyst for hydrogen and carbon black production by catalytic cracking of methane, and a preparation method of the catalyst, which comprises the following steps:

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

[0141] (2) Weigh 10 g of ammonium bicarbonate and add it to 500 ml of deionized water, and obtain an aqueous solution containing ammonium ions by stirring at 80°C at a speed of 150 r / min for 60 min; under the condition of 80°C, the first mixed solution and the aqueous solution containing ammonium ions are introduced into a flask in parallel flow, and a second mixed solution is obtained after stirring uniformly;

[0142] (3) The second mixed solution is evaporated to dryness at 80°C at a speed of 150 r / min, when the second mixed solution is changed into a sticky wet gel, the stirring speed is increased to 400 r / min and the temperature is increased to 100°C, and the evaporation to dryness is continued until a fluffy material is formed; then the fluffy material is placed in an electric heating constant temperature air drying oven for drying for 12 h, the drying temperature is set to 110°C, after drying is completed, calcination is carried out in a muffle furnace for 5 h, the calcination temperature is 800°C, the calcination atmosphere is air, after cooling, the catalyst is crushed with a mortar and sieved with an 80 mesh screen, to obtain the catalyst for hydrogen production and carbon black by catalytic cracking of methane.

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

[0144] The catalyst prepared in the present example is subjected to SEM-EDS analysis, Figure 4 The mapping diagram of the active component in the catalyst prepared in the present example is shown in FIG. 1. Figure 4 It can be seen that, in the present example, the main active component nickel in the synthesized catalyst is not easy to agglomerate and has good dispersibility.

[0145] The catalyst prepared in the present example is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 40.9%, 2.08 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not decrease obviously.

[0146] Comparative Example 4

[0147] The present example provides a catalyst for hydrogen production and carbon black by catalytic cracking of methane, and the preparation method of the catalyst comprises the following steps:

[0148] (1) Put 3.4 g of nickel nitrate as a precursor of the main active component, 1.0 g of lanthanum nitrate and 0.6 g of copper nitrate as precursors of the auxiliary active component, and 2.6 g of aluminum nitrate as a precursor of the carrier into 200 ml of deionized water, and obtain a first mixed solution by fully stirring at 80°C; weigh 13 g of PEG-2000 into 100 ml of deionized water, and obtain a PEG-2000 solution by fully stirring until uniform; add the PEG-2000 solution into the first mixed solution, and obtain a second mixed solution by constant temperature stirring at 80°C for 120 min at a stirring speed of 150 r / min;

[0149] (2) Weigh 4 g of maleic acid and 10 g of ammonium chloride into 200 ml of deionized water, and obtain a maleic acid-ammonium chloride complexing agent solution by constant temperature stirring at 80°C for 120 min at a stirring speed of 150 r / min; add the second mixed solution into the complexing agent solution under the condition of constant temperature stirring at 80°C, and obtain a third mixed solution by dropwise adding at a speed of 10 ml / min;

[0150] (3) Weigh 10 g of ammonium bicarbonate into 500 ml of deionized water, and obtain an aqueous solution containing ammonium ions by constant temperature stirring at 80°C for 60 min at a stirring speed of 150 r / min; add the third mixed solution and the aqueous solution containing ammonium ions into a flask under the condition of constant temperature stirring at 80°C, and obtain a fourth mixed solution by fully stirring;

[0151] (4) Stir the fourth mixed solution at 80°C at a stirring speed of 150 r / min until dry, increase the stirring speed to 400 r / min and the temperature to 100°C when the fourth mixed solution turns into a wet gel in the form of viscous matter, continue to dry until a fluffy matter is formed, then dry the fluffy matter in an electric heating constant temperature air drying oven for 12 h, set the drying temperature to 110°C, after drying, calcine in a muffle furnace for 5 h, the calcination temperature is 800°C, the calcination atmosphere is air, after cooling, crush with a mortar, and sieve with an 80 mesh sieve, to obtain the catalyst for methane catalytic cracking for hydrogen and carbon black.

[0152] The content of nickel in the catalyst is 42%, the content of lanthanum is 8%, the content of copper is 11%, and the content of aluminum is 39% in terms of the content of metal oxides.

[0153] The catalyst prepared in this example is subjected to catalyst performance evaluation. The results show that the average conversion rate of methane reaches 43.5%, 2.24 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not decrease obviously.

[0154] Comparative Example 5

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

[0156] (1) Put 3.4 g of nickel nitrate as a precursor of the main active component, 1.0 g of lanthanum nitrate and 0.6 g of copper nitrate as precursors of the auxiliary active component, and 2.6 g of aluminum nitrate as a precursor of the carrier into 200 ml of deionized water, and obtain a first mixed solution by fully stirring at 80°C; weigh 5 g of PEG-2000 and 8 g of ammonium citrate into 100 ml of deionized water, and obtain a PEG-2000-ammonium citrate complex dispersant solution by fully stirring; add the PEG-2000-ammonium citrate complex dispersant solution into the first mixed solution, and obtain a second mixed solution by stirring at 80°C for 120 min at a stirring speed of 150 r / min;

[0157] (2) Weigh 14 g of maleic acid into 200 ml of deionized water, and obtain a maleic acid solution by stirring at 80°C at a speed of 150 r / min for 120 min; add the second mixed solution into the maleic acid solution dropwise under stirring at 80°C at a dropwise speed of 10 ml / min, and obtain a third mixed solution;

[0158] (3) Weigh 10 g of ammonium bicarbonate into 500 ml of deionized water, and obtain an aqueous solution containing ammonium ions by stirring at 80°C at a speed of 150 r / min for 60 min; add the third mixed solution and the aqueous solution containing ammonium ions into a flask under parallel flow at 80°C, and obtain a fourth mixed solution by stirring uniformly;

[0159] (4) Stir the fourth mixed solution at 80°C at a speed of 150 r / min until it is evaporated to dryness; when the fourth mixed solution is changed into a wet gel in a sticky state, increase the stirring speed to 400 r / min and the temperature to 100°C, and continue to evaporate to dryness until a fluffy material is formed; then put the fluffy material into an electric heating constant-temperature air drying oven for drying for 12 h, set the drying temperature to 110°C, and after drying is completed, bake in a muffle furnace for 5 h at a baking temperature of 800°C in an air atmosphere, cool, crush with a mortar, sieve through an 80-mesh sieve, and obtain the catalyst for methane catalytic cracking for hydrogen production and carbon black.

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

[0161] The catalyst prepared in this example is subjected to catalyst performance evaluation. The results show that the average methane conversion rate reaches 43.7%, 2.28 g of carbon black is obtained, the reaction time is 10 h, and the catalyst activity does not decrease obviously.

[0162] Compared with the examples 1-5, the catalyst prepared in the example 1 has the main active component uniformly distributed in the surface layer, and the main active component has good dispersibility. However, the catalyst prepared in the comparative example 3 has the main active component nickel easily agglomerated and poor dispersibility, because the complex dispersant and the ammonium salt complexing agent are not used. Under the same catalytic performance evaluation conditions, the average methane conversion rate of the example 1 reaches 47.3%, and 2.9g of carbon black is obtained. However, the average methane conversion rate and the carbon black yield of the comparative examples 1-5 are obviously lower than those of the example 1.

[0163] In conclusion, the catalyst for the catalytic cracking of methane to produce hydrogen and carbon black is synthesized by the sol-gel method. The catalyst has the advantages of good dispersing effect of the active component, high methane conversion rate, high carbon black production capacity, good stability and the like, because of the synergistic effect of the specific complex dispersant and the ammonium salt complexing agent. The catalyst has simple preparation process and low cost. When the catalyst is used in the reaction of the catalytic cracking of methane to produce hydrogen and carbon black, the high methane conversion rate and the high yield of hydrogen and carbon black can be obtained under the conditions of low reaction temperature and high space velocity.

Claims

1. A method for preparing a catalyst for methane catalytic cracking to produce hydrogen and carbon black, comprising the following steps: (1) mixing a precursor of a main active component, a precursor of an auxiliary 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; the dispersant comprises a combination of a first dispersant and a second dispersant, the first dispersant comprises a combination of one or more of polyethylene glycol, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester and polyoxyethylene alkylamine; the second dispersant comprises a combination of one or more of ammonium citrate, polystyrene maleate, cetyltrimethylammonium bromide, sodium laurate, polyvinyl alcohol and sodium dodecylbenzenesulfonate; the amount of the dispersant added is 1%-30% of the total mass of the second mixed solution; (2) adding the second mixed solution dropwise into an aqueous solution of a complexing agent, and stirring to obtain a third mixed solution; the complexing agent in the aqueous solution of the complexing agent comprises 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 form an ammonium salt complexing agent; (3) mixing the third mixed solution with an aqueous solution containing ammonium ions, and stirring to obtain a fourth mixed solution; (4) evaporating the fourth mixed solution to obtain a fluffy material, drying and calcining the fluffy material, and then crushing and sieving to obtain the catalyst for methane catalytic cracking to produce hydrogen and carbon black; wherein the main active component comprises a combination of one or more of nickel, cobalt, nickel oxide and cobalt oxide; the auxiliary active component comprises a metal and / or metal oxide of one or more of Fe, Mo, Zn, Cu, Cr, W, Ru, Pt, Re, Pd, Ce and La; and the carrier comprises a combination of one or more of MgO, γ-Al2O3, SiO2, TiO2, ZrO2, graphite and perovskite. In terms of the total mass of the catalyst for methane catalytic cracking to produce hydrogen and carbon black, the main active component accounts for 10%-50% in terms of oxide, the auxiliary active component accounts for 0.1%-30% in terms of oxide, and the carrier accounts for the balance. In step (1), the precursor of the main active component, the precursor of the auxiliary active component and the precursor of the carrier respectively comprise soluble salt compounds of the main active component, the auxiliary active component and the carrier. In step (1), the mass ratio of the first dispersant to the second dispersant is 1: (1-2.5). In step (1), the dispersant comprises a combination of polyethylene glycol and ammonium citrate, a combination of fatty alcohol polyoxyethylene ether and polystyrene maleate, a combination of alkylphenol polyoxyethylene ether and cetyltrimethylammonium bromide, a combination of fatty acid polyoxyethylene ester and sodium laurate, a combination of polyoxyethylene alkylamine and polyvinyl alcohol, or a combination of polyoxyethylene lauryl ether and sodium dodecylbenzenesulfonate. ​ ​ ​ ​ ​ ​ ​ 2. The production method according to claim 1, wherein, ​ 3. The production method according to claim 1, wherein ​ 4. The production method according to claim 1, wherein ​ 5. The production method according to claim 1, wherein ​ 6. The production method according to claim 1, wherein In step (2), the mass ratio of the total amount of the precursors of the main active component, the precursors of the auxiliary active component and the precursors 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).

7. The production method according to claim 1, wherein In step (3), the mass ratio of the ammonium ion in the ammonium ion-containing aqueous solution to the total amount of the precursors of the main active component, the precursors of the auxiliary active component and the precursors of the carrier in the second mixed solution is (2-4):(7-11).

8. The production method according to claim 1, wherein In step (3), the ammonium ion-containing aqueous solution comprises an ammonium salt aqueous solution and / or ammonia water.

9. The production method according to claim 8, wherein In step (3), the ammonium salt in the ammonium salt aqueous solution comprises one or a combination of several of ammonium bicarbonate, ammonium carbonate and ammonium nitrate.

10. The production method according to claim 1, wherein, In step (3), the third mixed solution and the ammonium ion-containing aqueous solution are mixed by being introduced into a container in parallel flow.

11. The method of producing according to claim 1, wherein, In step (4), the process of evaporating the fourth mixed solution to dryness specifically comprises: evaporating the fourth mixed solution to dryness at 65-90°C with stirring at a speed of 100-300 r / min, when the fourth mixed solution turns into a sticky wet gel, increasing the stirring speed to 300-500 r / min and increasing the temperature to 90-110°C, and continuing to evaporate until the fluffy material is formed.

12. Use of the catalyst prepared by the method for preparing a catalyst for catalytic cracking of methane to produce hydrogen and carbon black according to any one of claims 1-11 in catalytic cracking of methane to produce hydrogen and carbon black.

13. Use according to claim 12, wherein, The use comprises: using a fixed bed reactor, and catalytically cracking a raw gas comprising methane to produce hydrogen and carbon black under the action of the catalyst; wherein, based on the loading amount of the catalyst being 0.5 g, the feed flow of the raw gas is 10-400 ml / min; the reaction temperature of the catalytic cracking is 400-900°C, and the reaction pressure is normal pressure.

14. Use according to claim 13, wherein, The raw gas comprises pure methane and / or other methane-rich gas.

15. The use according to claim 13, wherein, Based on the loading amount of the catalyst being 0.5 g, the feed flow of the raw gas is 50-200 ml / min.

16. The use according to claim 13, wherein, The reaction temperature of the catalytic cracking is 500-800°C.

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