An anti-sulfur methanation dry reforming catalyst, a preparation method and application thereof

Abstract

The application discloses a sulfur-resistant dry-reforming catalyst for methane, a preparation method and application thereof, and belongs to the technical field of catalysts. The catalyst is of a core-shell structure, the active component supported by a carrier is the core, and SiO2 is the shell. The novel sulfur-resistant dry-reforming catalyst for methane prepared by the application has the characteristics of high catalytic activity and anti-carbon deposition by adopting NiRu nano-alloy as the active component; the anti-sulfur capacity is enhanced by adopting MoO3 and V2O5 as H2S adsorption-promoting species to promote the oxidative removal of the H2S species. The oxygen storage capacity of the CeO2 carrier can adjust the oxidation-reduction environment, reduce the H2S species, and stabilize the metal particles, and the porous SiO2 shell can form a high-transparency skeleton structure, so that the multi-component jointly delays sulfur poisoning, and the catalyst has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, and more specifically to an anti-sulfur catalyst for methane dry reforming, its preparation method, and its application. Background Technology

[0002] Dry reforming (DRM) technology can synergistically utilize methane and carbon dioxide, two greenhouse gases, to produce syngas with a suitable H2 / CO ratio. This gas can be used to synthesize high-value-added oxygen-containing chemicals. Although inhibiting carbon deposition and resisting metal sintering remain the core technical bottlenecks for the long-term operation of DRM catalysts, the poisoning effect of trace sulfur components in the feed gas on nickel-based catalysts in industrial applications cannot be ignored—for example, in mainstream methane sources such as natural gas and biogas, the H2S concentration can reach 200 ppm, which can easily lead to catalyst deactivation. Although modern industrial desulfurization processes are relatively mature, their high infrastructure costs and continuous operation consume significant capital investment; at the same time, fluctuations in the sulfur content of upstream gas sources may cause a sharp increase in the sulfur concentration in the reaction gas, posing a potential threat to the downstream catalytic system. Therefore, developing sulfur-tolerant DRM catalysts has become a research hotspot, and developing a methane dry reforming catalyst that is resistant to sulfur poisoning and maintains high activity during the reaction process is a key technical direction that urgently needs to be overcome.

[0003] Common catalysts used for dry reforming of methane, such as nickel-based catalysts, are unfavorable for the large-scale application of sulfur-resistant catalysts for dry reforming of methane due to their sintering and poisoning properties.

[0004] Therefore, providing a highly active noble metal-based anti-sulfur methane dry reforming catalyst and its preparation method is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a highly active noble metal-based methane dry reforming catalyst, its preparation method and application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A sulfur-resistant dry reforming catalyst, wherein the sulfur-resistant dry reforming catalyst has a core-shell structure with an active component supported on a support as the core and SiO2 as the shell;

[0008] The carrier is CeO2; the active component is NiRu-MoO3-V2O5.

[0009] The catalyst provided by this invention has a core-shell structure, with SiO2 as the shell, an active metal supported on a support as the core, and CeO2 as the support. The active metal is mainly a Ni and Ru alloy, and MoO3 and V2O5 are auxiliary agents. It is a methane dry reforming catalyst with high sulfur resistance.

[0010] The sulfur-resistant catalyst prepared by this invention exhibits excellent encapsulation properties. The material described in this invention has an encapsulation structure and a morphological appearance, which can isolate H2S particles from direct contact, thereby enhancing its sulfur resistance, providing excellent catalytic activity, and making it less susceptible to poisoning in an H2S atmosphere, demonstrating promising potential applications.

[0011] Furthermore, the Ni and Ru particles in the sulfur-resistant methane dry reforming catalyst are both 3-5 nm in size.

[0012] Furthermore, the catalyst is composed of uniformly sized nanoparticles stacked together, wherein the particle size distribution of the nanoparticles is 10–20 nm.

[0013] This invention also provides a method for preparing the above-mentioned anti-sulfur methane dry reforming catalyst, comprising the following steps:

[0014] (1) Prepare an aqueous solution of the precursor containing Ce source, then add a precipitant to obtain a precipitate, and dry the precipitate.

[0015] (2) The dried precipitate was placed in a Joule heating device for calcination to obtain CeO2 support;

[0016] (3) The Ru source, Mo source, V source and Ni source are mixed and dissolved in water and stirred evenly to form a mixed solution. An alkaline solution is prepared. The CeO2 support is dissolved in water and ultrasonically treated to obtain a support aqueous solution. The mixed solution is added to the support aqueous solution using a constant flow titration pump, and the alkaline solution is added at the same time. After the addition is completed, the mixture is stirred evenly. After aging and centrifugation, the collected product is dried and placed in a Joule heating device for calcination to obtain the NiRu-MoO3-V2O5 / CeO2 catalyst.

[0017] (4) Cyclohexane, polyethylene glycol octylphenyl ether, and n-hexanol were dissolved in water to form a microemulsion, and the NiRu-MoO3-V2O5 / CeO2 catalyst was dissolved in water to form a catalyst aqueous solution. The microemulsion and the catalyst aqueous solution were then mixed and ultrasonically stirred until homogeneous. TEOS solution was then slowly added, centrifuged and dried, and then rapidly calcined using a Joule heating instrument to obtain a core-shell structured NiRu-MoO3-V2O5 / CeO2@SiO2 anti-sulfur methane dry reforming catalyst.

[0018] The preparation method of this invention uses relatively simple raw materials and is prepared with specialized equipment, showing great application potential. The precipitant and ultrasonic titration mixing method used in this invention is highly beneficial for the high dispersibility and size standardization of the product, while simultaneously forming better encapsulation, resulting in encapsulated nanoparticles. This invention discloses a sulfur-resistant methane dry reforming catalyst and its preparation method. After calcination, it exhibits good crystallization and an encapsulated morphology, enabling its sulfur resistance to remain active for extended periods below 600℃. This method is simple to prepare and has significant industrial production value.

[0019] Furthermore, the Ce source mentioned in step (1) is at least one of Ce nitrate, sulfate, and chloride;

[0020] The precipitant is ammonia water with a mass concentration of 5-15%.

[0021] Furthermore, the Joule heating device described in step (2) has a heating rate of 500℃-1000℃ / s and a calcination time of 0.1-10s.

[0022] Further, in step (3), the Mo source is at least one of Mo nitrate, acetate, sulfate, and chloride; the Ru source is at least one of Ru nitrate, acetate, sulfate, and chloride; the V source is at least one of V nitrate, acetate, sulfate, and chloride; the Ni source is at least one of Ni nitrate, acetate, sulfate, and chloride; and the molar concentration of metal ions in the mixed solution is 0.1–0.50 mol / L.

[0023] Furthermore, the alkaline solution is an aqueous solution of hydroxide and / or citric acid, preferably hydroxide; the concentration of the alkaline solution is 0.1–5.0 mol / L.

[0024] The concentration of the carrier aqueous solution is 0.03-0.04 g / mL.

[0025] Furthermore, the volume ratio of the mixed solution, alkaline solution, and carrier aqueous solution in step (3) is (0.1-10):1:(0.1-10);

[0026] The Joule heating device has a heating rate of 500℃-1000℃ / s and a calcination time of 0.1-10s.

[0027] The mixed solution and alkaline solution described in step (3) are stirred with the carrier aqueous solution at 0 to 100°C for 1 to 24 hours.

[0028] The mixing method for the mixed solution and alkaline solution with the carrier aqueous solution is to slowly pump the mixed solution and alkaline solution into the carrier aqueous solution; or, the mixed solution and alkaline solution and the carrier aqueous solution are mixed and precipitated in parallel.

[0029] Preferably, the mixed solution and alkaline solution are slowly pumped into the carrier aqueous solution.

[0030] Furthermore, the aging process in step (3) is a 30°C water bath for 1 hour, and the centrifugation process is a 10,000 rpm centrifugation for 5 minutes.

[0031] Furthermore, in step (4), the volume ratio of the microemulsion to the alkaline solution is 0.1 to 10:1;

[0032] The mass ratio of the NiRu-MoO3-V2O5 / CeO2 catalyst to the volume ratio of the TEOS solution is 0.5 g: 3 mL;

[0033] The TEOS solution has a mass concentration of 98%.

[0034] The calcination heating rate is 500-1000℃ / s, preferably 800℃ / s; the calcination atmosphere is static air or flowing air, preferably static air; and the calcination time is 0.1-10s.

[0035] The microemulsion and catalyst aqueous solution described in step (4) are stirred at 0 to 100°C for 1 to 24 hours.

[0036] The TEOS solution is slowly dripped into the mixture using a constant flow pump.

[0037] Furthermore, in step (4), the TEOS solution can be replaced with any one or more of sodium silicate, potassium silicate, silica sol, methyl orthosilicate, ethyl orthosilicate, butyl orthosilicate, and propyl orthosilicate.

[0038] The beneficial effects of this invention are as follows:

[0039] (1) The sulfur-resistant catalyst prepared by this invention combines the high activity of bimetals with the sulfur resistance of the additives, and further isolates the poisoning of sulfur species by utilizing the core-shell structure, thus solving the problem that the activity and sulfur resistance cannot be improved together, and has a wide range of application value.

[0040] (2) This invention utilizes the characteristics of Joule heating for rapid heating and cooling. The heating and cooling time during calcination can be ignored, and the calcined sample has the characteristics of high specific surface area and small particle size. Attached Figure Description

[0041] Figure 1 The graph shows the anti-poisoning effect of the sulfur-resistant methane dry reforming catalyst prepared in Example 1 of this invention on H2S compared with that of a conventional sulfur-resistant methane dry reforming catalyst.

[0042] Figure 2The graph shows the anti-poisoning effect of the sulfur-resistant methane dry reforming catalyst prepared in Example 1 of this invention on different concentrations of H2S.

[0043] Figure 3 This is a schematic diagram of the sulfur-resistant methane dry reforming catalyst prepared in Example 1 of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1

[0046] In this embodiment, a sulfur-resistant methane dry reforming catalyst NiRu-MoO3-V2O5 / CeO2@SiO2 was prepared. The catalyst has a core-shell structure, with SiO2 as the shell and the active component supported on a support as the core.

[0047] Mass percentage of active components in the catalyst: Ru 1%, Ni 10%.

[0048] Step 1: Preparation of CeO2 support

[0049] 21.7 g of Ce(NO3)3·6H2O was dissolved in 200 mL of water to obtain a solution A containing Ce source (hereinafter referred to as solution A). The solution was then placed in a water bath at 30 °C. 10% ammonia solution was added dropwise to solution A at a rate of 1 mL / min using a constant flow pump until the pH reached 10. The solution was stirred for 3 h and aged for 1 h. After filtration and washing, the solution was dried at 110 °C for 12 h and then calcined at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the CeO2 support.

[0050] Step 2: Preparation of NiRu-MoO3-V2O5 / CeO2

[0051] Weigh 1g of CeO2 obtained in step 1 and dissolve it in 50mL of deionized water to prepare solution B (hereinafter referred to as solution B). Heat the solution in a water bath at 30℃. Prepare 100mL of aqueous solution with 0.55g of Ni(NO3)2·6H2O, 50mL of aqueous solution with 0.02g of RuCl3, 50mL of aqueous solution with 0.17g of VCl3, 50mL of aqueous solution with 0.12g of Na2MoO4, and 350mL of alkaline solution with 0.7g of NaOH. Stir each solution thoroughly and then add it dropwise to solution B at a rate of 1mL / min using a constant flow pump. When the pH = 10.5, stop adding the alkaline solution. Stir for 3h, age for 1h, filter and wash, dry at 80℃ for 12h, and then calcine at 800℃ / s for 1s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2 catalyst.

[0052] Step 3: Preparation of NiRu-MoO3-V2O5 / CeO2@SiO2

[0053] Weigh 0.5 g of the catalyst prepared in step 2 and prepare a 200 mL solution; take 100 mL of cyclohexane, 50 mL of polyethylene glycol octylphenyl ether, and 30 mL of n-hexanol to prepare a 180 mL microemulsion; mix the two and stir under ultrasonic conditions for 30 min, during which 80 mL of 10% ammonia water is added, and then 3 mL of TEOS solution is added dropwise through a constant flow pump. Continue stirring for 20 h to obtain the microemulsion. After centrifugation and washing, dry at 110 °C for 12 h, and then calcine at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2@SiO2 catalyst.

[0054] Example 2

[0055] In this embodiment, a sulfur-resistant methane dry reforming catalyst NiRu-MoO3-V2O5 / CeO2@SiO2 was prepared. The catalyst has a core-shell structure, with SiO2 as the shell and the active component supported on a support as the core.

[0056] Mass percentage of active components in the catalyst: Ru 0.5%, Ni 10%.

[0057] Step 1: Preparation of CeO2 support

[0058] 21.7 g of Ce(NO3)3·6H2O was dissolved in 200 mL of water to obtain a solution A containing Ce source (hereinafter referred to as solution A). The solution was then placed in a water bath at 30 °C. 10% ammonia solution was added dropwise to solution A at a rate of 1 mL / min using a constant flow pump until the pH reached 10. The solution was stirred for 3 h and aged for 1 h. After filtration and washing, the solution was dried at 110 °C for 12 h and then calcined at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the CeO2 support.

[0059] Step 2: Preparation of NiRu-MoO3-V2O5 / CeO2

[0060] Weigh 1g of CeO2 obtained in step 1 and dissolve it in 50mL of deionized water to prepare solution B (hereinafter referred to as solution B). Heat the solution in a water bath at 30℃. Prepare 100mL of aqueous solution with 0.55g of Ni(NO3)2·6H2O, 50mL of aqueous solution with 0.01g of RuCl3, 50mL of aqueous solution with 0.17g of VCl3, 50mL of aqueous solution with 0.12g of Na2MoO4, and 350mL of alkaline solution with 0.7g of NaOH. Stir each solution thoroughly and then add it dropwise to solution B at a rate of 1mL / min using a constant flow pump. When the pH = 10.5, stop adding the alkaline solution. Stir for 3h, age for 1h, filter and wash, dry at 80℃ for 12h, and then calcine at 800℃ / s for 1s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2 catalyst.

[0061] Step 3: Preparation of NiRu-MoO3-V2O5 / CeO2@SiO2

[0062] Weigh 0.5 g of the substance prepared in step 2 and prepare a 200 mL solution; take 100 mL of cyclohexane, 50 mL of polyethylene glycol octylphenyl ether, and 30 mL of n-hexanol to prepare a 180 mL microemulsion; mix the two and stir under ultrasonic conditions for 30 min, during which 80 mL of 10% ammonia water is added, and then 3 mL of TEOS solution is added dropwise through a constant flow pump. Continue stirring for 20 h to obtain a microemulsion. After centrifugation and washing, dry at 110 °C for 12 h, and then calcine at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2@SiO2 catalyst.

[0063] Example 3

[0064] In this embodiment, a sulfur-resistant methane dry reforming catalyst NiRu-MoO3-V2O5 / CeO2@SiO2 was prepared. The catalyst has a core-shell structure, with SiO2 as the shell and the active component supported on a support as the core.

[0065] Mass percentage of active components in the catalyst: Ru 2%, Ni 10%.

[0066] Step 1: Preparation of CeO2 support

[0067] 21.7 g of Ce(NO3)3·6H2O was dissolved in 200 mL of water to obtain a solution A containing Ce source (hereinafter referred to as solution A). The solution was then placed in a water bath at 30 °C. 10% ammonia solution was added dropwise to solution A at a rate of 1 mL / min using a constant flow pump until the pH reached 10. The solution was stirred for 3 h and aged for 1 h. After filtration and washing, the solution was dried at 110 °C for 12 h and then calcined at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the CeO2 support.

[0068] Step 2: Preparation of NiRu-MoO3-V2O5 / CeO2

[0069] Weigh 1g of CeO2 obtained in step 1 and dissolve it in 50mL of deionized water to prepare solution B (hereinafter referred to as solution B). Heat the solution in a water bath at 30℃. Prepare 100mL of aqueous solution with 0.55g of Ni(NO3)2·6H2O, 50mL of aqueous solution with 0.04g of RuCl3, 50mL of aqueous solution with 0.17g of VCl3, 50mL of aqueous solution with 0.12g of Na2MoO4, and 350mL of alkaline solution with 0.7g of NaOH. Stir each solution thoroughly and then add it dropwise to solution B at a rate of 1mL / min using a constant flow pump. When the pH = 10.5, stop adding the alkaline solution. Stir for 3h, age for 1h, filter and wash, dry at 80℃ for 12h, and then calcine at a rate of 800℃ / s for 1s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2 catalyst.

[0070] Step 3: Preparation of NiRu-MoO3-V2O5 / CeO2@SiO2

[0071] Weigh 0.5 g of the substance prepared in step 2 and prepare a 200 mL solution; take 100 mL of cyclohexane, 50 mL of polyethylene glycol octylphenyl ether, and 30 mL of n-hexanol to prepare a 180 mL microemulsion; mix the two and stir under ultrasonic conditions for 30 min, during which 80 mL of 10% ammonia water is added, and then 3 mL of TEOS solution is added dropwise through a constant flow pump. Continue stirring for 20 h to obtain a microemulsion. After centrifugation and washing, dry at 110 °C for 12 h, and then calcine at a rate of 800 °C / s for 1 s using a Joule heating device to obtain the NiRu-MoO3-V2O5 / CeO2@SiO2 catalyst.

[0072] Comparative Example 1

[0073] The bimetallic catalyst (Ni / Al2O3)-SiO2 in this comparative example was prepared using a conventional method, the specific steps of which are as follows:

[0074] Step 1: Preparation of Ni / Al2O3 support

[0075] γ-Al2O3 was dispersed in an aqueous solution of Ni(NO3)2·6H2O and stirred until homogeneous. The solution was then evaporated at 90°C, and residual moisture was removed in an oven at 120°C. The solution was then placed in a muffle furnace and heated to 500°C at a heating rate of 5°C / min and calcined in air for 2 hours to obtain the Ni / Al2O3 support.

[0076] Step 2: Preparation of (Ni / Al2O3)-SiO2

[0077] Weigh 0.5 g of the substance prepared in step 1 and disperse it in 20 mL of ethanol solution; prepare 180 mL of tetraethoxysilane ethanol solution; mix the two and stir under ultrasonic conditions for 30 min, during which 200 mL of 10% ammonia water is added and stirred for 5 h to obtain a microemulsion. After centrifugation and washing, dry at 90 °C for 12 h and then calcine at 300 °C for 1 h by air forging at a rate of 1 °C / s to obtain (Ni / Al2O3)-SiO2 catalyst.

[0078] The catalyst in this invention is a highly active sulfur-resistant methane dry reforming catalyst with good crystallinity and well-dispersed encapsulated morphology. This catalyst has potential applications in areas such as industrial exhaust gas emissions.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a sulfur-resistant methane dry reforming catalyst, characterized in that, The anti-sulfur methane dry reforming catalyst has a core-shell structure with an active component supported on a support as the core and SiO2 as the shell; wherein, the support is CeO2; and the active component is NiRu-MoO3-V2O5. The size of Ni and Ru particles in the anti-sulfur methane dry reforming catalyst is 3-5 nm, and the particle size of the anti-sulfur methane dry reforming catalyst is 10-20 nm. The preparation steps of the anti-sulfur methane dry reforming catalyst are as follows: (1) Prepare an aqueous solution of the precursor containing Ce source, then add a precipitant to obtain a precipitate, and dry the precipitate; (2) The dried precipitate was placed in a Joule heating device for calcination to obtain CeO2 support; (3) The Ru source, Mo source, V source and Ni source are mixed and dissolved in water and stirred evenly to form a mixed solution. An alkaline solution is prepared. The CeO2 support is dissolved in water and ultrasonically treated to obtain a support aqueous solution. The mixed solution is added to the support aqueous solution using a constant flow titration pump, and the alkaline solution is added at the same time. After the addition is completed, the mixture is stirred evenly. After aging and centrifugation, the collected product is dried and placed in a Joule heating device for calcination to obtain the NiRu-MoO3-V2O5 / CeO2 catalyst. The Mo source is at least one of the nitrate, acetate, sulfate and chloride of Mo. The Ru source is at least one of the nitrate, acetate, sulfate and chloride of Ru. The V source is at least one of the nitrate, acetate, sulfate and chloride of V. The Ni source is at least one of the nitrate, acetate, sulfate and chloride of Ni. The molar concentration of metal ions in the mixed solution is 0.1 to 0.

50. The alkaline solution is an aqueous solution of hydroxide with a concentration of 0.1–5.0 mol / L; the aqueous solution of the carrier has a concentration of 0.03–0.04 g / mL. (4) Cyclohexane, polyethylene glycol octylphenyl ether, and n-hexanol were dissolved in water to form a microemulsion, and the NiRu-MoO3-V2O5 / CeO2 catalyst was dissolved in water to form a catalyst aqueous solution. The microemulsion and the catalyst aqueous solution were then mixed and ultrasonically stirred until homogeneous. Then, tetraethyl orthosilicate (TEOS) solution was slowly added, centrifuged and dried, and rapidly calcined using a Joule heating instrument to obtain a core-shell structured NiRu-MoO3-V2O5 / CeO2@SiO2 anti-sulfur methane dry reforming catalyst. The volume ratio of the microemulsion to the alkaline solution was 0.1–10:

1. The mass ratio of the NiRu-MoO3-V2O5 / CeO2 catalyst to the TEOS solution was 0.5 g:3 mL. The mass concentration of the TEOS solution was 98%. The heating rate of the calcination was 500–1000 °C / s, and the calcination time was 0.1–10 s.

2. The method for preparing a sulfur-resistant methane dry reforming catalyst according to claim 1, characterized in that, The Ce source mentioned in step (1) is at least one of Ce nitrate, sulfate, and chloride.

3. The method for preparing a sulfur-resistant methane dry reforming catalyst according to claim 1, characterized in that, The Joule heating device described in step (2) has a heating rate of 500℃-1000℃ / s and a calcination time of 0.1-10s.

4. The method for preparing a sulfur-resistant methane dry reforming catalyst according to claim 1, characterized in that, The volume ratio of the mixed solution, alkaline solution and carrier aqueous solution in step (3) is (0.1-10):1:(0.1-10), the heating rate of the Joule heating device is 500℃-1000℃ / s, and the calcination time is 0.1-10s.

5. The application of a sulfur-resistant methane dry reforming catalyst prepared by the method of any one of claims 1-4 in a sulfur-resistant methane dry reforming reaction.

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