Methane promotion catalyst for chemical gasification process and preparation method thereof

Abstract

The application discloses a kind of chemical coal gasification process methane promotion catalyst and its preparation method, belong to coal gasification and catalytic chemistry technical field.The catalyst includes composite carrier, active metal nickel and catalytic adjuvant molybdenum oxide;Composite carrier is the composite metal oxide with core-shell structure, inner core is lanthanum oxide particle, shell is cerium-zirconium solid solution of mesoporous structure.Preparation method includes: first, prepare lanthanum oxide inner core particle, then form cerium-zirconium solid solution shell on its surface by sol-gel method to build core-shell carrier, then load molybdenum adjuvant and nickel active component in sequence, finally, it is activated by reduction and is prepared.The catalyst utilizes the structural stability of core-shell carrier, the oxygen storage capacity of cerium-zirconium solid solution, the alkalinity of lanthanum oxide and the synergistic effect of molybdenum adjuvant, and shows high activity, high methane selectivity, excellent sintering resistance, carbon deposition resistance and sulfur resistance in coal gasification synthesis gas methanation reaction, and is suitable for the treatment of industrial coal gasification crude synthesis gas containing complex impurities.

Description

Technical Field

[0001] This invention relates to the fields of coal gasification and catalytic chemistry, specifically to a methane boosting catalyst for chemical coal gasification processes and its preparation method. Background Technology

[0002] Coal gasification is used to convert carbonaceous feedstocks such as coal, coke, and biomass into syngas, whose main components are CO and H2. With the increasing demand for high-calorific-value clean energy sources and chemical feedstocks such as natural gas substitutes and synthetic natural gas (SNG), how to directionally promote methane generation and increase the methane concentration in the product gas during coal gasification has become an important research direction.

[0003] Existing coal gasification technologies typically influence methane yield by adjusting process conditions such as gasification temperature and pressure, but the adjustment range is limited and energy consumption is high. Some studies have attempted to introduce catalysts into the gasifier or syngas post-processing stage to promote reactions such as CO methanation, but these methods suffer from problems such as catalyst sintering, carbon deposition and deactivation, loss of active components, and low methane selectivity in the high-temperature, high-moisture-pressure crude coal gas environment.

[0004] Therefore, developing a methane boosting catalyst with high activity, high selectivity, high stability and long lifespan under typical coal gasification environments is of great significance for improving the economy and added value of coal gasification processes. Summary of the Invention

[0005] In view of this, and in view of the shortcomings of the prior art, the present invention aims to provide a methane boosting catalyst for the chemical coal gasification process and its preparation method. The catalyst can effectively promote the methanation of syngas and related reactions under coal gasification conditions, significantly increase the concentration and yield of methane in the outlet gas, and has good anti-carbon deposition, anti-sintering and hydrothermal stability.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a methane-enhancing catalyst for a chemical coal gasification process, comprising a composite support, an active metal component, and a catalyst promoter; the composite support is a core-shell structured composite metal oxide, wherein the core is lanthanum oxide (La₂O₃) particles, and the outer shell is a mesoporous cerium-zirconium solid solution (Ce₂O₃). x Zr 1-x O2), where 0.7≤x≤0.9; the active metal component is metallic nickel (Ni) supported on the composite support; the catalyst is an oxide of molybdenum (Mo) supported on the composite support.

[0007] As a further embodiment of the present invention, based on the total mass of the catalyst, the content of each component is as follows: the content of metallic nickel (Ni) is 8-15 wt%, the content of molybdenum (calculated as MoO3) is 3-8 wt%, the content of lanthanum oxide (La2O3) core is 10-20 wt%, and the balance is the outer shell of the cerium-zirconium solid solution.

[0008] As a further aspect of the present invention, the cerium-zirconium solid solution of the outer shell (Ce x Zr 1-x O2 has a bimodal mesoporous structure, including primary mesopores with a pore size of 3-5 nm and secondary mesopores with a pore size of 10-20 nm.

[0009] As a further aspect of the present invention, the active metal component, nickel, exists in the form of nanoparticles with an average particle size of 5-15 nm, and is highly dispersed on the surface and within the pores of the composite carrier.

[0010] As a further aspect of the present invention, the average particle size of the lanthanum oxide (La2O3) core particles is 50-200 nm.

[0011] Secondly, the present invention also provides a method for preparing a methane boosting catalyst in a chemical coal gasification process, comprising the following steps: S1. Preparation of lanthanum oxide (La2O3) core particles: Using a uniform precipitation method, lanthanum salt and urea are used as raw materials to generate La(OH)3 precursor through hydrothermal or heating reaction. After separation, washing, drying and calcination, lanthanum oxide (La2O3) particles are obtained. S2. Construction of a core-shell composite carrier: Using a sol-gel encapsulation method, the lanthanum oxide (La₂O₃) particles obtained in step S1 are dispersed in a solvent of ethanol, isopropanol, or aqueous phase. A mixed solution containing a cerium source, a zirconium source, and a complexing agent is added. A gel layer is formed on the surface of the lanthanum oxide (La₂O₃) particles through a hydrolysis-condensation reaction. Subsequently, after aging, drying, and calcination, Ce₂O₃ is obtained. x Zr 1-x O2@La2O3 composite carrier; S3. Loading molybdenum additive: The molybdenum source solution is loaded onto the composite support obtained in step S2 by impregnation, and then dried and calcined to obtain a molybdenum-containing intermediate; S4. Loading nickel active components and reduction activation: The nickel source solution is loaded onto the molybdenum-containing intermediate obtained in step S3 by impregnation. After drying, the intermediate is subjected to programmed temperature reduction in a reducing atmosphere to obtain the methane boosting catalyst.

[0012] As a further aspect of the present invention, in step S1, the roasting temperature is 500-700°C and the roasting time is 3-6 hours.

[0013] As a further embodiment of the present invention, in step S2, the cerium source is one of cerium nitrate, cerium ammonium nitrate, or cerium chloride; the zirconium source is zirconium oxynitrate or zirconium oxychloride; the complexing agent is one of citric acid, tartaric acid, or ethylenediaminetetraacetic acid, and the total molar ratio of the complexing agent to cerium and zirconium metal ions is (1.0-1.5):1.

[0014] As a further embodiment of the present invention, in step S2, the roasting temperature is 550-700°C and the roasting time is 3-6 hours; in step S3, the roasting temperature is 550-700°C and the roasting time is 3-6 hours.

[0015] As a further aspect of the present invention, in step S4, the reducing atmosphere is hydrogen or a mixture containing hydrogen; the conditions for the programmed temperature reduction are: heating from room temperature to 400-600 at a rate of 1-5 / min, and maintaining at that temperature for 2-6 hours.

[0016] Compared with existing technologies, the methane enhancement catalyst for chemical coal gasification processes and its preparation method of the present invention improve the activity, selectivity, and stability of the catalyst in the coal gasification methanation reaction, and have the following beneficial effects: 1. Possesses excellent catalytic performance and high methane selectivity: In this invention, the basic sites of the La2O3 core and the Ce2O3 shell of the catalyst... x Zr 1-x The oxygen storage properties of O2 and the electronic modulation effect of MoO3 promoter produce a synergistic effect, effectively promoting the dissociation and directional hydrogenation of CO, and strongly guiding the reaction to generate CH4. Under typical coal gasification crude syngas atmosphere, and under the conditions shown in the examples, this catalyst can achieve an initial CO conversion rate of over 94%, and maintain high activity stability in long-term testing, significantly improving the yield and purity of the target product.

[0017] 2. Possesses excellent thermal stability and anti-sintering ability: This invention uses a cerium-zirconium solid solution with high cerium content (Ce). x Zr 1-x O2, acting as the outer shell, possesses excellent high-temperature thermal stability. The bimodal mesoporous structure of 3-5 nm and 10-20 nm provides a stable framework, effectively inhibiting the migration and aggregation of active nickel nanoparticles under high-temperature reaction conditions, thus maintaining highly dispersed active centers and extending catalyst lifetime. Furthermore, it inhibits carbon deposition from both physical structure and chemical properties perspectives. On the one hand, Ce... x Zr 1-x The excellent oxygen storage capacity (OSC) of the O2 shell can dynamically remove carbon precursors formed during the reaction; on the other hand, the La2O3 component can effectively regulate surface carbon chemistry and inhibit deep carbon deposition.

[0018] 3. Significant Sulfur Resistance and Long-Term Stability: The MoO3 additive plays a crucial role in this invention. In H2S-containing feed gas, molybdenum (Mo) species preferentially react with sulfur to form a stable phase, effectively protecting active Ni sites from irreversible deep sulfur poisoning. This enhances the catalyst's tolerance to common sulfur impurities in raw coal gasification gas, broadening its feed gas adaptability. The core-shell structure constructed via the sol-gel method achieves a strong chemical bond between the outer shell and the core, preventing the functional layers from peeling off during use. This integrated design ensures the catalyst's mechanical strength and structural integrity under high-speed gas flow impact and temperature cycling, guaranteeing its long-term stable operation.

[0019] In summary, this invention utilizes the La2O3 kernel @Ce x Zr 1-x The innovative combination of the O2 shell composite support structure and the "Ni-Mo" active-auxiliary system provides a methanation catalyst with balanced and significantly improved performance in terms of activity, selectivity, anti-coking, anti-sintering, and sulfur resistance. The preparation process is mature and controllable, which can effectively meet the industrial demand for efficient, stable, and long-life methane enhancement catalysts in chemical coal gasification processes, and has significant technical and economic benefits.

[0020] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to specific embodiments. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0022] Example 1 This embodiment provides a method for preparing a methane boosting catalyst for a chemical coal gasification process, which has the following composition: Ni 12 wt%, MoO 35 wt%, La2O3 15 wt%, Ce 0.8 Zr 0.2 A methane-boosting catalyst for industrial coal gasification, with an oxidation state of 68 wt%, was named sample Cat-1. Its preparation steps are as follows: Step S1: Preparation of lanthanum oxide (La2O3) core particles: 1. Weigh 14.33 g of lanthanum nitrate hexahydrate (La(NO3)3·6H2O) and dissolve it in 200 mL of deionized water to prepare solution A.

[0023] 2. Weigh 12.01 g of urea (CO(NH2)2) and dissolve it in 100 mL of deionized water to prepare solution B.

[0024] 3. Mix solutions A and B, place in a 90℃ water bath and stir magnetically for 4 hours. Urea decomposes and releases OH-. -The La(OH)3 precursor is uniformly precipitated.

[0025] 4. Cool the resulting suspension to room temperature, centrifuge, and wash three times each with deionized water and ethanol.

[0026] 5. Dry the washed precipitate at 110℃ for 12 hours.

[0027] 6. The dried powder was placed in a muffle furnace and calcined at 600°C at a rate of 2°C / min in air atmosphere for 4 hours to obtain white, porous La2O3 particles.

[0028] Step S2: Constructing a core-shell composite carrier (Ce 0.8 Zr 0.2 O2@La2O3): 1. Take 3.0 g of the La2O3 particles obtained in step S1, disperse them in 150 mL of anhydrous ethanol, and sonicate for 30 minutes to form a uniform suspension.

[0029] 2. Weigh 19.36 g of cerium nitrate hexahydrate ((NH4)2Ce(NO3)6) and 3.22 g of zirconium nitrate pentahydrate (ZrO(NO3)2·5H2O) (Ce:Zr molar ratio = 4:1, corresponding to Ce... 0.8 Zr 0.2 O2) was dissolved in 50 mL of deionized water.

[0030] 3. Add 12.61 g of citric acid monohydrate (C6H8O7·H2O) to the solution from the previous step as a complexing agent, and stir until completely dissolved. The total molar ratio of citric acid to cerium and zirconium metal ions is 1.2:1.

[0031] 4. The mixed solution prepared in steps 2 and 3 is slowly added dropwise to the La2O3 ethanol suspension from step 1 under vigorous stirring. After the addition is complete, stirring continues for 6 hours to allow the sol-gel process to fully occur on the surface of the La2O3 particles.

[0032] 5. After standing for 12 hours, the solvent was evaporated at 80°C to obtain a gel-like solid.

[0033] 6. The gel solid was dried at 110℃ overnight, then placed in a muffle furnace and calcined in air at a rate of 3℃ / min to 600℃ for 5 hours to obtain a pale yellow core-shell composite support Ce. 0.8 Zr 0.2 O2@La2O3.

[0034] Step S3: Loading molybdenum (Mo) additive: 1. Weigh 0.50 g of ammonium heptamolybdate ((NH4)6Mo7O) 24Dissolve 4H2O in deionized water to prepare an impregnation solution with a volume exactly equal to the water absorption rate of the composite carrier obtained in step S2 (equal volume impregnation).

[0035] 2. Add the above impregnation solution dropwise to 5.0 g of the composite carrier prepared in step S2, and let it stand at room temperature for 12 hours for impregnation.

[0036] 3. The impregnated material is dried at 110°C for 6 hours, and then calcined in a muffle furnace at 400°C in air atmosphere for 3 hours to obtain an intermediate loaded with MoO3 (denoted as MoO3 / Ce). 0.8 Zr 0.2 O2@La2O3).

[0037] Step S4: Loading nickel (Ni) active components and reduction activation: 1. Weigh 3.10 g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and dissolve it in deionized water to prepare an impregnation solution with a volume exactly equal to the water absorption rate of the intermediate obtained in step S3.

[0038] 2. Add the above impregnation solution dropwise to 5.0 g of the intermediate obtained in step S3, and let it stand at room temperature for 12 hours for impregnation.

[0039] 3. Dry the impregnated material at 110℃ for 12 hours.

[0040] 4. The dried precursor powder is loaded into a tube-type reduction furnace and heated from room temperature to 500°C at a rate of 2°C / min under a pure H2 atmosphere (flow rate 50 mL / min), and maintained at this temperature for 4 hours.

[0041] 5. After the reduction is complete, the sample is cooled to room temperature under H2 atmosphere to obtain the final catalyst sample, denoted as Cat-1.

[0042] The catalyst sample (Cat-1) prepared above was determined by inductively coupled plasma atomic emission spectrometry to have a Ni content of 11.8 wt% and a Mo content (calculated as Mo) of 3.3 wt% (corresponding to a MoO3 content of 5.0 wt%), which meets the preparation requirements.

[0043] Example 2 This embodiment provides a method for preparing a methane boosting catalyst for a chemical coal gasification process, which has the following composition: Ni 10 wt%, MoO3 6.5 wt%, La2O3 12 wt%, Ce 0.75 Zr 0.25 A 71.5 wt% methane-boosting catalyst for industrial coal gasification, named sample Cat-2, was prepared as follows: Step S1: Preparation of lanthanum oxide (La2O3) core particles: 1. Weigh 11.46 g of lanthanum nitrate hexahydrate (La(NO3)3·6H2O) and 9.61 g of urea (CO(NH2)2), and dissolve them separately in 150 mL of deionized water.

[0044] 2. After mixing the two solutions, transfer them to a 100 mL polytetrafluoroethylene-lined hydrothermal reactor and react at 120°C for 12 hours to carry out hydrothermal synthesis.

[0045] 3. After the reaction is complete, allow the mixture to cool naturally, centrifuge to collect the precipitate, and wash it three times each with deionized water and ethanol, alternating between the two.

[0046] 4. Dry the precipitate at 100℃ for 10 hours.

[0047] 5. The dried powder was calcined in air at a temperature increased to 550°C at a rate of 2.5°C / min for 5 hours to obtain La2O3 particles. Particle size analysis showed that the average particle size was approximately 80 nm, which meets the requirements of claim 5.

[0048] Step S2: Constructing a core-shell composite carrier (Ce 0.75 Zr 0.25 O2@La2O3): 1. Take 2.4 g of the La2O3 particles obtained in step S1, disperse them in 200 mL of isopropanol, and sonicate for 40 minutes.

[0049] 2. Weigh out 16.28 g of cerium nitrate hexahydrate ((NH4)2Ce(NO3)6) and 4.83 g of zirconium nitrate pentahydrate (ZrO(NO3)2·5H2O) respectively (Ce:Zr molar ratio = 3:1, corresponding to Ce... 0.75 Zr 0.25 O2) were dissolved together in 60 mL of deionized water.

[0050] 3. Add 13.0 g of tartaric acid (C4H6O6) as a complexing agent to the solution from the previous step, and stir to dissolve. The total molar ratio of the complexing agent to cerium and zirconium metal ions is 1.3:1, which meets the requirements of claim 8.

[0051] 4. Under vigorous stirring, slowly add the mixed solution prepared in steps 2 and 3 to the La2O3 isopropanol suspension in step 1. After the addition is complete, continue stirring for 8 hours.

[0052] 5. Allow the mixture to stand at room temperature for 24 hours to age, then remove most of the solvent by rotary evaporation at 70°C, and then dry it in an oven at 100°C for 12 hours.

[0053] 6. After grinding the dried solid, place it in a muffle furnace and calcine it at 580℃ for 5.5 hours in air atmosphere at a rate of 2℃ / min to obtain the core-shell structured composite support Ce. 0.75 Zr 0.25 O2@La2O3.

[0054] Step S3: Loading molybdenum (Mo) additive: 1. Weigh 0.675 g of ammonium heptamolybdate ((NH4)6Mo7O 24 Dissolve 4H2O in deionized water to prepare an equal volume of impregnation solution.

[0055] 2. The impregnation solution is evenly applied to 4.0 g of the composite carrier prepared in step S2, and allowed to stand at room temperature for 10 hours.

[0056] 3. After drying at 110℃ for 6 hours, the product was calcined in a tube furnace at 380℃ for 4 hours with flowing air (100 mL / min) at a rate of 2℃ / min to obtain a molybdenum-containing intermediate.

[0057] Step S4: Loading nickel (Ni) active components and reduction activation: 1. Weigh 2.07 g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and prepare an equal volume of impregnation solution.

[0058] 2. Impregnate 4.0 g of the molybdenum-containing intermediate obtained in step S3 with the impregnation solution and let it stand at room temperature for 10 hours.

[0059] 3. Dry at 100℃ for 10 hours.

[0060] 4. Place the dried sample in a tube furnace and heat it from room temperature to 480°C at a rate of 3°C / min under a 10% H2 / Ar mixed gas atmosphere (flow rate 100 mL / min). Maintain the temperature at this point for 3 hours.

[0061] 5. After reduction, the catalyst was cooled to below 50°C under an H2 / Ar atmosphere and then passivated with nitrogen containing trace amounts of oxygen to obtain the catalyst sample, denoted as Cat-2.

[0062] The catalyst sample (Cat-2) prepared above was determined by inductively coupled plasma atomic emission spectrometry to have a Ni content of 9.7 wt% and a Mo content (calculated as Mo) of 4.34 wt% (corresponding to a MoO3 content of 6.5 wt%), which meets the preparation requirements.

[0063] Example 3 This embodiment provides a method for preparing a methane boosting catalyst for a chemical coal gasification process, which has the following composition: Ni 8 wt%, MoO3 7 wt%, La2O3 18 wt%, Ce0.7 Zr 0.3 A methane-boosting catalyst for industrial coal gasification, with an oxidation state of 67 wt%, was named sample Cat-3. Its preparation steps are as follows: Step S1: Preparation of lanthanum oxide (La2O3) core particles: 1. Weigh 17.20 g of lanthanum nitrate hexahydrate (La(NO3)3·6H2O) and 14.41 g of urea (CO(NH2)2), dissolve them separately in 200 mL of deionized water, and mix them.

[0064] 2. The mixed solution was vigorously stirred and heated in an oil bath at 95°C for 6 hours to allow for uniform precipitation.

[0065] 3. The La(OH)3 precipitate obtained by centrifugation was washed with deionized water until neutral, and then washed twice with ethanol.

[0066] 4. Dry the precipitate at 120℃ for 10 hours.

[0067] 5. The dried precursor was calcined in air at a temperature increased to 680°C at a rate of 3°C / min for 3.5 hours to obtain La2O3 particles. Particle size analysis showed that the average particle size was approximately 180 nm, which is within the upper limit of the range described in claim 5.

[0068] Step S2: Constructing a core-shell composite carrier (Ce 0.7 Zr 0.3 O2@La2O3): 1. Take 3.6 g of the La2O3 particles obtained in step S1, disperse them in 200 mL of deionized water, add an appropriate amount of polyethylene glycol (PEG-20000) as a dispersant, and sonicate for 1 hour.

[0069] 2. Weigh 15.31 g of cerium nitrate hexahydrate ((NH4)2Ce(NO3)6) and 7.25 g of zirconium nitrate pentahydrate (ZrO(NO3)2·5H2O) (Ce:Zr molar ratio = 7:3, corresponding to Ce... 0.7 Zr 0.3 O2) were dissolved together in 80 mL of deionized water.

[0070] 3. Add 16.8 g of disodium ethylenediaminetetraacetate (Na2H2EDTA·2H2O) to the solution from the previous step as a complexing agent, adjust the pH to 5-6 with ammonia water, and stir until completely dissolved. The total molar ratio of EDTA to cerium and zirconium metal ions is 1.1:1.

[0071] 4. Under vigorous stirring, slowly add the mixed solution prepared in steps 2 and 3 to the La2O3 aqueous suspension in step 1. After the addition is complete, continue stirring for 10 hours to ensure a complete hydrolysis-condensation reaction.

[0072] 5. The resulting slurry was aged at 60°C for 36 hours, and then dried at 100°C for 24 hours.

[0073] 6. Grind the dried lumps and calcine them in air at a rate of 2°C / min to 680°C for 4 hours to obtain Ce. 0.7 Zr 0.3 O2@La2O3 composite carrier.

[0074] Step S3: Loading molybdenum (Mo) additive: 1. Weigh 0.98 g of ammonium heptamolybdate ((NH4)6Mo7O) 24 Prepare an equal volume of impregnation solution by adding 4H2O.

[0075] 2. The impregnation solution is evenly applied to 5.0 g of the composite carrier prepared in step S2, and allowed to stand at room temperature for 15 hours.

[0076] 3. After drying at 120℃ for 8 hours, the product was calcined in air at 400℃ for 3 hours to obtain a molybdenum-containing intermediate.

[0077] Step S4: Loading nickel (Ni) active components and reduction activation: 1. Weigh 2.48 g of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and prepare an equal volume of impregnation solution.

[0078] 2. Impregnate 5.0 g of the molybdenum-containing intermediate obtained in step S3 with the impregnation solution and let it stand at room temperature for 15 hours.

[0079] 3. Dry at 120℃ for 10 hours.

[0080] 4. The dried precursor was heated to 450℃ at a rate of 1.5℃ / min under a pure H2 atmosphere and reduced for 5 hours to obtain the final catalyst sample, denoted as Cat-3.

[0081] The catalyst sample (Cat-3) prepared above was determined by inductively coupled plasma atomic emission spectrometry to have a Ni content of 7.9 wt% and a Mo content (calculated as Mo) of 4.67 wt% (corresponding to a MoO3 content of 7.0 wt%), which meets the preparation requirements.

[0082] Comparative experiment: Comparative Example 1 To verify the importance of the core-shell structure, a physical hybrid support comparison sample was prepared. This comparison example provides a method for preparing a methane-boosting catalyst for a chemical coal gasification process, which differs from Example 3 in that: The La2O3 particles obtained in step S1 are combined with the Ce particles prepared separately in step S2. 0.7 Zr0.3 O2 powder (preparation method is the same as S2 but without adding La2O3 core, directly generating Ce) 0.7 Zr 0.3 O2), mechanically mixed at the same mass ratio as Cat-3, and then Mo and Ni were loaded according to the exact same S3 and S4 steps to obtain control sample D1 (Ni-Mo / Ce). 0.7 Zr 0.3 O2@La2O3).

[0083] Comparative Example 2 To verify the role of the Mo additive, this comparative example provides a method for preparing a methane boosting catalyst for a chemical coal gasification process, which differs from Example 3 in that: Ce obtained in step S2 0.7 Zr 0.3 On the O2@La2O3 support, step S3 is skipped, and step S4 is performed directly to load Ni, resulting in the control sample D2 (Ni / Ce). 0.7 Zr 0.3 O2@La2O3), controlling the Ni loading to be the same as Cat-3.

[0084] Performance testing: The evaluation was conducted in a fixed-bed reactor, and the tests were divided into three groups: Test A (Standard Conditions): Same as Example 1 and Example 2, conditions are: 400℃, 2.0 MPa, GHSV=5000 h. -1 The reaction gas contained 100 ppm H2S. The reactor was run for 100 hours. The catalyst loading was 0.5 mL (40-60 mesh). The composition of the reactor outlet gas was analyzed by online gas chromatography. The evaluation consisted of two phases: 1) Initial activity test: data were collected after the reaction had stabilized for 2 hours; 2) Stability test: data were collected after 100 hours of continuous reaction to examine activity decay.

[0085] Test B (High Sulfur Conditions): Same harsh conditions as Example 2 (simulated crude coal gas containing 100 ppm H2S, 400℃, 2.0 MPa, GHSV=5000 h). -1 The H2S concentration was increased to 300 ppm, with other conditions the same as in test A. The system was run continuously for 150 hours under the same temperature and pressure.

[0086] Test C (High Moisture Conditions): To investigate the resistance to hydrothermal sintering, the moisture concentration was increased to 20 vol% based on Test A conditions, and the reaction temperature was increased to 420℃. The test was run for 200 hours.

[0087] The test results are shown in Table 1 below:

[0088] The above tests show that even with a lower Ni loading (8 wt%) and different preparation parameters—a higher calcination temperature of 680℃ and the use of EDTA complexing agent—Cat-3 still exhibited excellent initial activity (90.5% CO conversion, 96.2% CH4 selectivity) and good 100-hour stability in the standard tests, with an activity retention rate of 97%, fully demonstrating the feasibility and robustness of the technical solution within the scope of the claims of this invention. Comparative Example D1 (without a core-shell structure) showed significantly lower performance than Cat-3 in all tests. Especially under high moisture conditions (test C), the stability of Comparative Example D1 decreased more significantly, with a conversion rate of 71.8% after 200 hours compared to Cat-3's 84.3%. This indicates that Ce... x Zr 1-x The core-shell structure, in which the O2 shell tightly encloses the La2O3 core, is crucial for stabilizing the active center and preventing component separation and sintering under harsh hydrothermal conditions. It is a core structural feature for achieving high stability.

[0089] Compared to sample D2 (without Mo additive), which showed acceptable activity in the initial testing phase, its stability was extremely poor under the sulfur-containing conditions of tests A and B, with activity decaying much faster than Cat-3. This directly demonstrates the decisive role of Mo additive in improving the catalyst's sulfur resistance. Mo species, acting as sulfur traps, effectively mitigated the poisoning of active Ni sites by H2S. Cat-1, Cat-2, and Cat-3 all exhibited the best overall performance under the three stringent testing conditions, especially in long-term stability under high moisture conditions. The activity retention rate of over 94% after 200 hours was particularly outstanding, attributed to the synergistic effect of the core-shell structure and the Mo additive: the core-shell support provides physical stability and resistance to hydrothermal sintering, while the Mo additive provides chemical resistance to sulfur toxicity. The combination of these two factors ensures the long-term operation of the catalyst in the complex and realistic coal gasification atmosphere.

[0090] Therefore, this invention utilizes the La2O3 kernel @Ce x Zr 1-x The innovative combination of the O2 shell composite support structure and the "Ni-Mo" active-auxiliary system provides a methanation catalyst with balanced and significantly improved performance in terms of activity, selectivity, anti-coking, anti-sintering, and sulfur resistance. The preparation process is mature and controllable, which can effectively meet the industrial demand for efficient, stable, and long-life methane enhancement catalysts in chemical coal gasification processes, and has significant technical and economic benefits.

[0091] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A methane boosting catalyst for a chemical coal gasification process, characterized in that, Includes composite supports, active metal components, and catalyst promoters; The composite carrier is a core-shell structured composite metal oxide, wherein the core is lanthanum oxide (La₂O₃) particles and the outer shell is a mesoporous cerium-zirconium solid solution (Ce). x Zr 1-x O2, wherein 0.7≤x≤0.9; the active metal component is nickel (Ni) supported on the composite support; the catalyst is an oxide of molybdenum (Mo) supported on the composite support.

2. The methane boosting catalyst for chemical coal gasification process according to claim 1, characterized in that, Based on the total mass of the catalyst, the contents of each component are as follows: the content of metallic nickel (Ni) is 8-15 wt%, the content of molybdenum (calculated as MoO3) is 3-8 wt%, the content of lanthanum oxide (La2O3) core is 10-20 wt%, and the balance is the outer shell of the cerium-zirconium solid solution.

3. The methane boosting catalyst for chemical coal gasification process according to claim 2, characterized in that, The cerium-zirconium solid solution of the outer shell. x Zr 1-x O2 has a bimodal mesoporous structure, including primary mesopores with a pore size of 3-5 nm and secondary mesopores with a pore size of 10-20 nm.

4. The methane boosting catalyst for chemical coal gasification process according to claim 1, characterized in that, The active metal component, nickel, exists in the form of nanoparticles with an average particle size of 5-15 nm and is highly dispersed on the surface and within the pores of the composite carrier.

5. The methane boosting catalyst for chemical coal gasification process according to claim 1, characterized in that, The average particle size of the lanthanum oxide La2O3 core particles is 50-200 nm.

6. A method for preparing a methane boosting catalyst for a chemical coal gasification process as described in any one of claims 1-5, characterized in that, The steps are as follows: S1. Preparation of lanthanum oxide La2O3 core particles: Using a uniform precipitation method, lanthanum salt and urea are used as raw materials to generate La(OH)3 precursor through hydrothermal or heating reaction. After separation, washing, drying and calcination, lanthanum oxide La2O3 particles are obtained. S2. Construction of a core-shell composite carrier: Using a sol-gel encapsulation method, the lanthanum oxide (La₂O₃) particles obtained in step S1 are dispersed in a solvent of ethanol, isopropanol, or aqueous phase. A mixed solution containing a cerium source, a zirconium source, and a complexing agent is added. A gel layer is formed on the surface of the lanthanum oxide (La₂O₃) particles through a hydrolysis-condensation reaction. Subsequently, the gel layer is aged, dried, and calcined to obtain Ce. x Zr 1-x O2@La2O3 composite carrier; S3. Loading molybdenum additive: The molybdenum source solution is loaded onto the composite support obtained in step S2 by impregnation, and then dried and calcined to obtain a molybdenum-containing intermediate; S4. Loading nickel active components and reduction activation: The nickel source solution is loaded onto the molybdenum-containing intermediate obtained in step S3 by impregnation. After drying, the intermediate is subjected to programmed temperature reduction in a reducing atmosphere to obtain the methane boosting catalyst.

7. The method for preparing the methane boosting catalyst in the chemical coal gasification process according to claim 6, characterized in that, In step S1, the roasting temperature is 500-700°C and the roasting time is 3-6 hours.

8. The method for preparing the methane boosting catalyst in the chemical coal gasification process according to claim 6, characterized in that, In step S2, the cerium source is one of cerium nitrate, cerium ammonium nitrate, or cerium chloride; the zirconium source is zirconium oxynitrate or zirconium oxychloride; the complexing agent is one of citric acid, tartaric acid, or ethylenediaminetetraacetic acid, and the total molar ratio of the complexing agent to cerium and zirconium metal ions is (1.0-1.5):

1.

9. The method for preparing the methane boosting catalyst for the chemical coal gasification process according to claim 6, characterized in that, In step S2, the roasting temperature is 550-700°C and the roasting time is 3-6 hours; in step S3, the roasting temperature is 550-700°C and the roasting time is 3-6 hours.

10. The method for preparing the methane boosting catalyst for the chemical coal gasification process according to claim 6, characterized in that, In step S4, the reducing atmosphere is hydrogen or a mixture containing hydrogen; the conditions for the programmed temperature reduction are: heating from room temperature to 400-600°C at a rate of 1-5°C / min, and maintaining at that temperature for 2-6 hours.

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