Preparation method of high-temperature-resistant methane catalyst for preparing natural gas from coke-oven gas

Abstract

The invention discloses a preparation method of a high-temperature-resistant methane catalyst for preparing natural gas from coke-oven gas, and belongs to the technical field of coal chemical industry. Comprising a carrier, a catalyst active component and an auxiliary agent, the catalyst active component is NiO, the catalyst auxiliary agent is MgO, La2O3 and SiO2, the carrier is Al2O3, and the catalyst comprises the following components in percentage by mass: 35 to 45 percent of NiO, 9 to 12 percent of MgO, 2.5 to 5 percent of La2O3, 3 to 5 percent of SiO2 and the balance of Al2O3. The invention also provides preparation steps of the catalyst and a method for enhancing interaction of metal carriers, and raw materials which do not cause pollution are selected at the same time. The prepared catalyst has high strength, sintering resistance, carbon deposition resistance and good high temperature resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of preparation of a methanation catalyst for coal chemical natural gas, and particularly relates to a preparation method of a high-temperature-resistant methanation catalyst for coke oven gas natural gas. BACKGROUND

[0002] China is the largest coke producer in the world, and coke oven gas natural gas is an important link. The methanation catalyst is the core and important carrier in the coke oven gas natural gas device, and is crucial to improve the methanation efficiency. The production and processing of high-temperature-resistant catalysts are expensive, and are restricted by technical and long-distance transportation conditions and other uncertain factors, and there is a potential risk of supply interruption. Therefore, the development of a new type of high-temperature-resistant methanation catalyst for coke oven gas natural gas is an urgent and difficult problem to be solved.

[0003] In recent years, domestic research institutions have carried out research work in the field of preparation and performance of methanation catalysts. Chinese patent CN1051985160 develops an isothermal methanation catalyst and a preparation method thereof, first prepares a mixed carrier by using a mechanical mixing method, and then prepares a methanation catalyst by stepwise impregnation of an additive and an active component; Chinese patent CN102139218A develops a coal-to-syngas complete methanation catalyst, which uses NiO as an active component, Al2O3 and MgO mixed to form a magnesium-aluminum spinel as a carrier, and one or two of rare earth metal oxides La2O3, CeO2 and Sm2O3 and one of alkaline oxides CaO, BaO and SrO as an additive. Chinese patent CN201110420364.1 discloses a catalyst for coal-to-natural gas and a preparation method thereof, which uses alumina as a carrier, nickel as a main active component, and rare earth as an additive. The mass percentage of the main components is respectively NiO 20-40%, La2O3 10-20%, Al2O3 40-60%, and graphite 3-10%. The catalyst preparation method for coal-to-natural gas includes a step of preparing a catalyst semi-product by a precipitation reaction, a drying step, a calcination step and a pressing forming step. The catalyst in the patent has high strength, good activity, thermal stability, good carbon resistance and good high-temperature resistance. However, there is still a sintering phenomenon under long-term high-temperature conditions, and it cannot meet the needs of high-temperature methanation. The thermal stability and carbon resistance of domestic methanation catalysts have not been obtained in industrial application data, especially under the condition of low recycle ratio of coke oven gas natural gas, the stability and activity of the methanation catalyst under the condition of long-term operation at an inlet total carbon content of about 6-7% and a bed temperature of more than 600℃ need to be further optimized. SUMMARY

[0004] The purpose of the present application is to provide a high-temperature-resistant and carbon-resistant methanation catalyst for use in the process of coke oven gas natural gas, which has good methanation activity and thermal stability under high temperature.

[0005] The application further provides a preparation method of the methane catalyst.

[0006] A preparation method of a high-temperature-resistant methane catalyst for preparing natural gas from coke oven gas, which comprises a carrier, a catalyst active component and an additive, the catalyst active component is NiO, the catalyst additive is MgO, La2O3 and SiO2, and the carrier is Al2O3, wherein the mass percentage of each component of the catalyst is as follows: 35-45% of NiO, 9-12% of MgO, 2.5-5% of La2O3, 3-5% of SiO2, and the rest is Al2O3.

[0007] A preparation method of a high-temperature-resistant methane catalyst for preparing natural gas from coke oven gas, which comprises the following steps: (1) first, a certain pseudo-boehmite is calcined at 800-1000 DEG C for 4h to prepare alumina; (2) a nickel-containing compound, a magnesium-containing compound, alumina and pseudo-boehmite are uniformly kneaded, then acetylacetone lanthanum acetylacetone solution is added to continue the uniform kneading, the mixture is dried and the solvent is recovered to obtain a required precursor; (3) the precursor obtained in step (2) is added into a methanol solution containing organosilicon ester and stirred uniformly, then a nickel-ammonium complex solution is added, soaked for 8-12h, and then dried at 90-110 DEG C to obtain a required powder; (4) the powder obtained in step (3) is added into an aqueous solution containing a reducing agent and soaked for 4h, filtered and dried, and then calcined at 600-800 DEG C for 4h to obtain a required semi-finished product; (5) the semi-finished product obtained in step (4) is added into graphite and cement to be tablet-shaped, and then treated in a water vapor and nitrogen atmosphere at 550-600 DEG C for 2-4h to obtain a product catalyst.

[0008] The nickel-containing compound is one of basic nickel carbonate, acetylacetone nickel or nickel acetate; the magnesium-containing compound is one or both of magnesium oxide and magnesium hydroxide; the mass ratio of alumina to pseudo-boehmite used in step (2) is 1:1-2; the solid-liquid volume ratio between the precursor and the methanol liquid in step (3) is 0.4-0.7, the amount of organosilicon ester, which is tetraethyl orthosilicate, accounts for 4-8% of the total silicon in the product catalyst; the nickel-ammonium complex solution used is an ammonium hydroxide and nickel acetate or basic nickel carbonate and ammonium carbonate complex solution, the molar ratio of NH3 / Ni is 4-8:1, and the amount of nickel accounts for 5-10% of the nickel in the product catalyst.

[0009] The reducing agent is one of hydrazine hydrate, L-ascorbic acid and glucose, the amount of the reducing agent is 0.2-0.5 mole ratio of the reducing agent to Ni, the water vapor content in the water vapor and nitrogen atmosphere in the step (5) is 60-75%, the methane catalyst is used for preparing natural gas from coke oven gas, the reaction temperature is 600-800 DEG C, and the catalyst needs to be reduced in a hydrogen atmosphere at 550 DEG C for 8 hours before use.

[0010] The application discloses the high thermal stability, anti-carbon deposition and high-strength methanation catalyst prepared by the preparation method.

[0011] Compared with the prior art, the application has the following beneficial technical effects: The application discloses a preparation method of a high-temperature-resistant methane catalyst for preparing natural gas from coke oven gas, which utilizes non-nitride-polluted raw materials, recycles organic solvents, uses mutual mixing of alumina and pseudo-boehmite as a carrier structure, adjusts catalyst sintering problems, and improves the overall catalyst structural strength. In the application, dry mixing and wet mixing are combined, a nickel source, a magnesium source and an aluminum source are mechanically mixed, and then acetylacetone solution of lanthanum acetylacetone is used for wet mixing. The acetylacetone lanthanum and acetylacetone nickel of the nickel source form hydrogen bonds with aluminum hydroxyl on the surface of Al2O3 and are highly dispersed and adsorbed on the surface of the carrier, the interaction between nickel and lanthanum and the carrier is strengthened, and migration and aggregation of active components are prevented. In addition, the nickel salt is added twice, the first time, the nickel salt is added in the form of powder, and the particle size is micron grade, which is difficult to form stable nickel aluminate spinel, and the second time, the nickel salt is added in the form of a nickel ammonium complex solution, and stable nickel aluminate spinel is formed. The chemical interaction force between nickel oxide and the carrier in unstable nickel aluminate spinel is moderate, the interaction between nickel oxide and the carrier in stable nickel aluminate spinel is relatively strong, the two complement each other, the low-temperature activity required by the catalyst is ensured, and long-term high-temperature activity is ensured. Organic silicon ester and magnesium hydroxide are added to adjust the carrier structural strength, the high-temperature strength of the carrier is improved, the organic silicon ester reacts with the nickel ammonium complex solution to generate nickel silicate by hydrolysis to generate SiO2, and the structure is good in heat resistance and stability. After the catalyst is formed, the catalyst is treated by high-temperature water vapor, the carrier surface is activated by water vapor, active MOxHy species are formed, strong electronic interaction is formed between the metal nanoparticles, the carrier is driven to migrate to the surface of the metal nanoparticles under high-temperature conditions, the strong interaction is still stable under the conditions of oxidation, reduction and water vapor atmosphere, the agglomeration of the methane reaction metal Ni particles under the water vapor atmosphere condition is effectively inhibited, the sintering resistance of the methane catalyst is improved, and finally, the methane catalyst with high activity, good thermal stability, anti-carbon deposition and high strength is obtained through the comprehensive interaction of the above aspects. DETAILED DESCRIPTION

[0012] The application is further described below in combination with specific embodiments, and the content is an explanation rather than a limitation of the application: The high-temperature-resistant methane catalyst comprises the following components in mass fraction: 35-45% of NiO, 9-12% of MgO, 2.5-5% of La2O3, 4-8% of SiO2 and the rest of Al2O3. Example 1

[0013] 1) 200g pseudo-boehmite was weighed and calcined at 800℃ for 4h to obtain alumina.

[0014] 2) 78.6g nickel acetylacetonate, 7.59g magnesium oxide, 11.4g alumina and 16.2g pseudo-boehmite were uniformly kneaded, 10.1g lanthanum acetylacetonate was dissolved in 45.5g acetylacetonate, and then the lanthanum acetylacetonate solution was added to the above-mentioned powder and uniformly kneaded again, and then the precursor I was obtained by drying and recovering the solvent acetylacetonate.

[0015] 3) 13.5g tetraethyl orthosilicate was dissolved in 50mL methanol, 9.76g ammonium carbonate was dissolved in 63g water, and then 6.9g basic nickel carbonate complex was added to clarify, the tetraethyl orthosilicate solution was added to the precursor I and uniformly mixed, then the nickel-ammonium complex solution was added and uniformly mixed, soaked for 8h, and then dried at 90℃ to obtain the precursor II.

[0016] 4) the precursor II was added to excess water, 4.19g hydrazine hydrate (content 85%) was added and uniformly mixed, soaked for 4h, filtered and dried, and then calcined at 600℃ for 4h, and then the obtained semi-finished product was mixed with graphite and cement to form a tablet, and then the tablet was treated at 600℃ in a nitrogen atmosphere containing 75% water vapor for 3h to obtain the product catalyst A, wherein NiO is 35%, MgO is 10%, La2O3 is 5%, SiO2 is 5%, and the rest is Al2O3. Example 2

[0017] 1) 100g pseudo-boehmite was weighed and calcined at 900℃ for 4h to obtain alumina.

[0018] 2) 44.2g basic nickel carbonate, 4.56g magnesium oxide, 6.61g magnesium hydroxide, 11.2g alumina and 24.1g pseudo-boehmite were uniformly kneaded, 6.11g lanthanum acetylacetonate was dissolved in 67.4g acetylacetonate, and then the lanthanum acetylacetonate solution was added to the above-mentioned powder and uniformly kneaded again, and then the precursor I was obtained by drying and recovering the solvent acetylacetonate.

[0019] 3) 21.7g tetraethyl orthosilicate was dissolved in 60mL methanol, 44.2g ammonia water was dissolved in 64g water, and then 14.4g nickel acetate was added to clarify, the tetraethyl orthosilicate solution was added to the precursor I and uniformly mixed, then the nickel-ammonium complex solution was added and uniformly mixed, soaked for 10h, and then dried at 100℃ to obtain the precursor II.

[0020] 4) Put the precursor II into excess water, then add 21.5 g L-ascorbic acid, mix well, soak for 4 h, filter and dry, then calcine the obtained semi-product at 700°C for 4 h, add graphite and cement to form tablets, then treat the tablets in a nitrogen atmosphere containing 60% water vapor at 550°C for 4 h, and the obtained product catalyst B is obtained, wherein NiO is 40%, MgO is 12%, La2O3 is 3%, SiO2 is 8%, and the rest is Al2O3. Example 3

[0021] 1) Weigh 100 g pseudo-boehmite, calcine at 1000°C for 4 h to obtain alumina.

[0022] 2) Weigh 63 g nickel acetate, 9.92 g magnesium hydroxide, 10.0 g alumina and 28.5 g pseudo-boehmite, mix well, dissolve 5.09 g lanthanum acetylacetate in 59 g acetylacetone, then add the lanthanum acetylacetone solution to the above-mentioned powder, continue to mix well, dry and recover the solvent acetylacetone to obtain the precursor I.

[0023] 3) Weigh 10.9 g tetraethyl orthosilicate and dissolve in 40 mL methanol, weigh 41.5 g ammonia water and dissolve in 60 g water, then add 18 g nickel acetate to complex and clarify, first add the tetraethyl orthosilicate solution to the precursor I and mix well, then add the nickel-ammonium complex solution and mix well, soak for 12 h, then evaporate at 110°C to obtain the precursor II.

[0024] 4) Put the precursor II into excess water, then add 41.2 g glucose, mix well, soak for 4 h, filter and dry, then calcine the obtained semi-product at 800°C for 4 h, add graphite and cement to form tablets, then treat the tablets in a nitrogen atmosphere containing 70% water vapor at 580°C for 2 h, and the obtained product catalyst C is obtained, wherein NiO is 45%, MgO is 9%, La2O3 is 2.5%, SiO2 is 4%, and the rest is Al2O3. Example 4

[0025] 1) Weigh 100 g pseudo-boehmite, calcine at 1000°C for 4 h to obtain alumina.

[0026] 2) Weigh 83.8 g nickel acetylacetate, 6.07 g magnesium oxide, 2.21 g magnesium hydroxide, 16.5 g alumina and 23.6 g pseudo-boehmite, mix well, dissolve 5.09 g lanthanum acetylacetone in 59 g acetylacetone, then add the lanthanum acetylacetone solution to the above-mentioned powder, continue to mix well, dry and recover the solvent acetylacetone to obtain the precursor I.

[0027] 3) Weigh 10.9 g of tetraethyl orthosilicate into 40 mL of methanol, weigh 44.2 g of ammonia water into 64 g of water, then add 14.4 g of nickel acetate to complex and clarify. First, add the tetraethyl orthosilicate solution into the precursor I and mix uniformly, then add the nickel-ammonium complex solution and mix uniformly, soak for 12 h, and then evaporate at 110°C to obtain the precursor II.

[0028] 4) Add the precursor II into excess water, then add 21.5 g of L-ascorbic acid and mix uniformly, soak for 4 h, filter and dry, and then calcine at 700°C for 4 h. Add the obtained semi-finished product into graphite and cement to form tablets, and then treat at 600°C in a nitrogen atmosphere containing 65% water vapor for 2 h to obtain the product catalyst D, wherein NiO is 40%, MgO is 10%, La2O3 is 2.5%, SiO2 is 4%, and the rest is Al2O3. Example 5

[0029] 1) Weigh 63 g of nickel acetate, 6.81 g of magnesium oxide, and 42.8 g of pseudo-boehmite and mix uniformly. Dissolve 5.09 g of lanthanum acetylacetonate in 59 g of acetylacetone, then add the lanthanum acetylacetonate solution into the above powder and continue to mix uniformly, dry, and recover the solvent acetylacetone to obtain the precursor I.

[0030] 2) Weigh 10.9 g of tetraethyl orthosilicate into 40 mL of methanol, weigh 41.5 g of ammonia water into 60 g of water, then add 18 g of nickel acetate to complex and clarify. First, add the tetraethyl orthosilicate solution into the precursor I and mix uniformly, then add the nickel-ammonium complex solution and mix uniformly, soak for 12 h, and then evaporate at 110°C to obtain the precursor II.

[0031] 3) Add the precursor II into excess water, then add 41.2 g of glucose and mix uniformly, soak for 4 h, filter and dry, and then calcine at 800°C for 4 h. Add the obtained semi-finished product into graphite and cement to form tablets, and then treat at 580°C in a nitrogen atmosphere containing 75% water vapor for 2 h to obtain the product catalyst E, wherein NiO is 45%, MgO is 9%, La2O3 is 2.5%, SiO2 is 4%, and the rest is Al2O3. Example 6

[0032] 1) Weigh 100 g of pseudo-boehmite and calcine at 1000°C for 4 h to obtain alumina.

[0033] 2) Weigh 63 g of nickel acetate, 9.92 g of magnesium hydroxide, 10.0 g of alumina, and 28.5 g of pseudo-boehmite and mix uniformly. Dissolve 5.09 g of lanthanum acetylacetonate in 59 g of acetylacetone, then add the lanthanum acetylacetonate solution into the above powder and continue to mix uniformly, dry, and recover the solvent acetylacetone to obtain the precursor I.

[0034] 3) Weigh 10.9 g of tetraethyl orthosilicate into 40 mL of methanol, weigh 41.5 g of ammonia water into 60 g of water, then add 18 g of nickel acetate complex to clarify. First, add the tetraethyl orthosilicate solution to the precursor I and mix well, then add the nickel ammonium complex solution and mix well. Soak for 12 h, then evaporate at 110°C to obtain precursor II.

[0035] 4) Add the precursor II to excess water, then add 41.2 g of glucose and mix well. Soak for 4 h, filter and dry, then calcine at 800°C for 4 h. Add the obtained semi-finished product to graphite and cement to form a tablet, and then age in water vapor at 90°C for 24 h to obtain the product catalyst C-1, which contains 45% NiO, 9% MgO, 2.5% La2O3, 4% SiO2, and the rest Al2O3. Comparative Example 1

[0036] Take commercial methanation catalyst J-1, which contains 50% NiO, 9% MgO, 3.1% La2O3, and the rest Al2O3. Comparative Example 2

[0037] Weigh 81 g of nickel acetate, 6.81 g of magnesium oxide, and 55.7 g of pseudo-boehmite, and mix well. Dissolve 6.06 g of lanthanum nitrate in 59 g of water, then simultaneously add the lanthanum nitrate solution and 10.3 g of silica sol to the above powder and continue to mix well. Dry, then calcine at 800°C for 4 h. Add the obtained semi-finished product to graphite and cement to form a tablet, and then age in water vapor at 90°C for 24 h to obtain the product catalyst J-2, which contains 45% NiO, 9% MgO, 3% La2O3, 4% SiO2, and the rest Al2O3. Comparative Example 3

[0038] 1) Weigh 62.1 g of basic nickel carbonate, 6.81 g of magnesium oxide, and 55.7 g of pseudo-boehmite, and mix well. Dissolve 6.06 g of lanthanum nitrate in 59 g of water, then add the lanthanum nitrate solution to the above powder and continue to mix well. Dry to obtain precursor I.

[0039] 2) Weigh 10.9 g of tetraethyl orthosilicate into 40 mL of methanol, add 30 g of water and 21.5 g of ammonia water and mix well, then add the precursor I and soak for 12 h. Evaporate at 110°C, then calcine at 800°C for 4 h. Add the obtained semi-finished product to graphite and cement to form a tablet, and then age in water vapor at 90°C for 24 h to obtain the product catalyst J-3, which contains 45% NiO, 9% MgO, 3% La2O3, 4% SiO2, and the rest Al2O3. Example 7

[0040] Methanation activity test of each catalyst in Examples 1-6 and Comparative Examples 1-3 at high temperature.

[0041] The raw material gas used in the test is prepared cylinder gas, which is prepared according to the component of industrial coke oven gas. The raw material water is pressurized by a horizontal flow pump, evaporated in an evaporator, mixed with the raw material gas, and then introduced into a reactor to react. The reactor is heated externally to control the outlet temperature. The outlet gas is cooled, separated, and part of it is sent to a chromatograph for component analysis, and the other part is directly discharged. The component of the raw material gas is shown in Table 1.

[0042] Table 1: Component of raw material gas

[0043] Catalyst reduction: at a temperature of 550℃, the hydrogen pressure is increased to 0.3MPa, and the reduction is carried out for 8h at a space velocity of 1000h-1.

[0044] High-temperature methanation activity test: after the reduction is completed, the hydrogen is disconnected, water vapor and raw material gas are introduced, the pressure is increased to 1.7MPa, the temperature is increased to 650℃, the raw material gas space velocity is 10000h-1, and the steam-gas ratio is 0.17. The coal gas high-temperature methanation reaction is carried out.

[0045] Heat resistance experiment: the temperature is 800℃, the pressure is 1.0MPa, the hydrogen is pressurized, and the time is 12h.

[0046] The test results are shown in Table 2.

[0047] Table 2: Component of outlet gas

[0048] From the above results, it can be seen that the catalysts 1-5 of the present application exhibit good activity and high-temperature resistance and anti-sintering performance. The activity is basically unchanged after heat resistance treatment, and the total conversion rate of CO and CO2 is 79%, which indicates that the catalysts 1-5 of the present application have good thermal stability. Except that the catalyst C-1 without high-temperature water vapor treatment has slightly poor heat resistance, the overall performance is better than that of the comparative examples. In order to further illustrate that the catalysts of the present application have good high-temperature resistance and anti-sintering performance, the catalyst B in Example 2 and the catalyst J-1 in Comparative Example 1 are subjected to a heat resistance experiment at 800℃ for 150h, and the activity test is carried out after cooling, as shown in Table 3. Table 3: Activity of catalyst B and J-1 after running for 150h

[0049] From the results in Table 3, it can be seen that the catalyst B still maintains good activity after long-time high-temperature treatment, and the catalyst does not appear sintering and deactivation, which indicates that the catalysts of the present application can be operated for a long time in a high-temperature environment after being improved by a series of methods in the above examples, and have good high-temperature resistance, anti-sintering, and anti-carbon deposition performance.

[0050] The application is not restricted to the foregoing specific embodiments. The application extends to any novel one, or any novel combination, of the features disclosed in this specification, and to any novel method or process disclosed in this specification or any novel combination thereof.

Claims

1. A method for preparing a high-temperature resistant methane catalyst for converting coke oven gas into natural gas, comprising a carrier, a catalyst active ingredient, and an additive, wherein the catalyst active ingredient is NiO, the catalyst additives are MgO, La2O3, and SiO2, the carrier is Al2O3, and the mass percentages of the catalyst components are as follows: NiO is 35-45%, MgO is 9-12%, La2O3 is 2.5-5%, SiO2 is 3-5%, and the remainder is Al2O3; The catalyst is characterized in that The method comprises the following preparation steps: (1) First, a certain amount of pseudo-boehmite is calcined at 800℃-1000℃ for 4 hours to obtain alumina; (2) mixing the nickel-containing compound with the magnesium-containing compound, alumina and pseudo-boehmite, adding the acetylacetone solution of lanthanum acetylacetonate and continuing to mix, drying and recovering the solvent to obtain the desired precursor; (3) Add the precursor obtained in step (2) to the methanol solution containing organosilicone ester and stir evenly, then add nickel ammonium complex solution, soak for 8-12 hours, and then evaporate to dryness at 90-110°C to obtain the desired powder; (4) The powder obtained in step (3) is added to an aqueous solution containing a reducing agent and soaked for 4 hours, filtered and dried, and calcined at 600-800°C for 4 hours to obtain the desired semi-finished product; (5) The semi-finished product obtained in step (4) is added with graphite and cement to form a sheet, and treated at 550-600°C in a steam and nitrogen atmosphere for 2-4 hours to obtain the resulting catalyst product.

2. The method for preparing a high-temperature resistant methane catalyst for producing natural gas from coke oven gas according to claim 1, characterized in that: The nickel-containing compound is one of basic nickel carbonate, nickel acetylacetonate or nickel acetate; the magnesium-containing compound is one or two of magnesium oxide and magnesium hydroxide.

3. The method for preparing a high-temperature resistant methane catalyst for converting coke oven gas into natural gas according to claim 1, characterized in that: The mass ratio of alumina to pseudo-boehmite used in step (2) is 1:1-2.

4. The method for preparing a high-temperature resistant methane catalyst for converting coke oven gas into natural gas according to claim 1, characterized in that: The solid-liquid volume ratio between the precursor and the methanol liquid in the step (3) is 0.4-0.7, the organic silicone ester is ethyl orthosilicate, and the amount used is 4-8% of the total silicon content in the product catalyst calculated as SiO2; the nickel ammonium complex liquid used is a complex solution of ammonia water and nickel acetate or basic nickel carbonate and ammonium carbonate, with an NH3 / Ni molar ratio of 4-8:1, and the amount of nickel used is 5-10% of the nickel in the product catalyst calculated as NiO.

5. The method for preparing a high-temperature resistant methane catalyst for producing natural gas from coke oven gas according to claim 2, characterized in that: The reducing agent is one of hydrazine hydrate, L-ascorbic acid and glucose.

6. The method for preparing a high-temperature resistant methane catalyst for converting coke oven gas into natural gas according to claim 2, characterized in that: In the step (5), the water vapor content in the water vapor and nitrogen atmosphere is 60-75%.

7. The method for preparing a high-temperature resistant methane catalyst for converting coke oven gas to natural gas according to claims 1 and 2, characterized in that: The methane catalyst is used to produce natural gas from coke oven gas at a reaction temperature of 600-800°C and needs to be reduced in a hydrogen atmosphere at 550°C for 8 hours before use.

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