A natural gas steam reforming catalyst and a method of making

Abstract

The present application relates to natural gas steam reforming catalyst technical field, especially in kind of natural gas steam reforming catalyst and preparation method. The catalyst includes noble metal active component and carrier material, the noble metal active component is at least one or two combinations of Pt, Pd, Ru, Ir, the content of noble metal active component is 0.1-5wt%, the carrier material includes at least one or two combinations of alumina, oxygen storage material or SBA-15 molecular sieve, the content of carrier material is 40-95wt%. The technical scheme of the present application uses the noble metal with higher adsorption activity for natural gas cracking as active substance, so that the working temperature of the catalyst is significantly reduced. At least one of alumina and oxygen storage material is used as a carrier to disperse the noble metal, and through the synergistic effect of the carrier and the noble metal, the catalytic activity is further improved. The operating temperature of the methane steam reforming catalyst is low, and the energy consumption is low. 550 DEG C can reach 60% conversion rate.

Description

Technical Field

[0001] This invention relates to the field of natural gas steam reforming catalyst technology, and particularly to a natural gas steam reforming catalyst and its preparation method. Background Technology

[0002] my country has proposed a carbon peaking and carbon neutrality strategy, aiming to peak CO2 emissions by 2030 and achieve net-zero CO2 emissions by 2060, thus reducing CO2 emissions from fossil fuel combustion. Replacing traditional fossil fuels with hydrogen as an energy carrier is a key direction. Hydrogen reacts with oxygen to produce only water, without emitting CO2 or pollutants, and natural gas reforming is currently the most important method for hydrogen production. However, this technology still has the following drawbacks: Methane steam reforming reactions commonly use nickel-based catalysts, and existing nickel-based catalysts face significant problems such as weak resistance to coking and short service life; nickel-based catalysts generally operate at temperatures of 800–900℃, while the flue gas temperature of gas generators is 500–600℃, making it difficult for ordinary nickel-based catalysts to exert their catalytic effect within this temperature range, requiring additional heat for the reaction. Summary of the Invention

[0003] The purpose of this invention is to address the technical shortcomings of existing nickel-based hydrogen production catalysts, such as high operating temperature, weak resistance to coking, and short service life, by providing a natural gas steam reforming catalyst and its preparation method.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A natural gas steam reforming catalyst, characterized in that it comprises a noble metal active component and a support material, wherein the noble metal active component is at least one or a combination of two of Pt, Pd, Ru, and Ir, and the content of the noble metal active component is 0.1-5 wt%.

[0006] The carrier material includes at least one or a combination of two of alumina, oxygen storage material, or SBA-15 molecular sieve, and the content of the carrier material is 82-95 wt%.

[0007] The methane steam reforming catalyst described in this invention is mainly used in the methane steam reforming reaction. Because the methane steam reforming reaction is a strongly endothermic reaction, it requires a high temperature. Existing nickel-based catalysts have low activity, resulting in very high reaction temperatures, typically 700–900°C. Additional heat must be supplied for the reaction, leading to high energy consumption during the heating process. The methane steam reforming catalyst provided in this application can lower the reaction temperature and effectively catalyze the reaction.

[0008] This invention employs a precious metal with higher adsorption activity for natural gas cracking as the active material, resulting in a significant reduction in the catalyst's operating temperature. At least one of alumina and oxygen storage materials is used as a support to disperse the precious metal; through the synergistic effect of the support and the precious metal, its catalytic activity is further enhanced. Due to the high price of precious metals, this invention controls the amount of precious metal used to within 5%, and the amount of support is 40-95%.

[0009] The oxygen storage material is a cerium-zirconium mixed oxide, preferably with a CeO2 content of 10%-60% and a ZrO2 content of 90%-40%.

[0010] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst further includes a structural aid, which comprises an oxide of any one of the metals La, Pr, Zr, Y, and Mg. The content of the structural aid is preferably 2-8 wt%.

[0011] By adding the above-mentioned structural additives to natural gas steam reforming catalysts, the high temperature resistance of the catalysts can be effectively improved, and the catalysts will not be deactivated under long-term high temperature conditions of 30,000 hours.

[0012] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst further includes an active additive, which includes at least one selected from Na2O, K2O, BaO, CaO, and MgO. The content of the active additive is preferably 0.1-5 wt%, more preferably 0.1-3 wt%. Using alkali metals or alkaline earth metals as additives neutralizes the acidity on the catalyst surface, improves the catalyst's reducibility, thereby promoting CO2 generation and enhancing the catalytic resistance to coking.

[0013] The active additive can work synergistically with the noble metal active component to reduce carbon buildup on the catalyst during the reforming process and extend the catalyst's service life.

[0014] As a preferred embodiment of the present invention, the specific surface area of ​​the carrier material ranges from 5 to 250 m². 2 / g. Further optimization yields a specific surface area of ​​60-200m². 2 / g.

[0015] As a preferred embodiment of the present invention, the particle size of the natural gas steam reforming catalyst is 0.5-500 μm. More preferably, the particle size range of the natural gas steam reforming catalyst is 1-200 μm.

[0016] As a preferred embodiment of the present invention, the pore volume of the natural gas steam reforming catalyst is 0.05-0.7 cm³. 3 / g.

[0017] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst is used to prepare a particulate natural gas steam reforming catalyst.

[0018] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst is used to prepare a honeycomb natural gas steam reforming catalyst.

[0019] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst is used to prepare a flat-plate natural gas steam reforming catalyst.

[0020] As a preferred embodiment of the present invention, the natural gas steam reforming catalyst is prepared according to the following method:

[0021] S1. Based on the mass ratio of each component, the precious metal active component, structural aid, and metal salt solution of the active aid are loaded onto the carrier material by equal volume impregnation method, and then dried and calcined to obtain catalyst powder.

[0022] S2. Add water and aluminum sol to the catalyst powder, grind it to form a slurry, coat it on a honeycomb ceramic substrate, dry it, and calcine it to obtain a honeycomb catalyst.

[0023] Preferably, a drying temperature range of 60-300℃ satisfies both drying effect and efficiency while reducing energy consumption. A calcination temperature of 200-1000℃ results in good activity and low energy consumption.

[0024] Preferably, the amount of impregnation solution used is 0.3-10 times the volume of the water pores in the carrier material.

[0025] Preferably, the equipment used in the impregnation step is any one of a reaction vessel, a water bath, or a mixer.

[0026] Organic compounds containing carboxyl or amine groups are added as dispersants during the impregnation process.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] 1. In the technical solution of the present invention, the methane steam reforming catalyst operates at a low temperature and consumes little energy, achieving a conversion rate of 60% at 550℃.

[0029] 2. Excellent resistance to carbon buildup, less prone to deactivation, and long service life. Alkali metals or alkaline earth metals are used as additives to neutralize the acidity on the catalyst surface, improving the catalyst's reducibility and thus promoting CO2 generation and enhancing its resistance to carbon buildup. Attached Figure Description

[0030] Figure 1 This is a graph showing the conversion rate of the catalyst fresh sample to CH4.

[0031] Figure 2 It is a graph showing the conversion rate of CH4 to the catalyst aged sample; Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings.

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example 1

[0035] This embodiment provides a Pt-Ir / Ce honeycomb monolithic catalyst with a Pt content of 0.4 wt% and an Ir content of 2.5 wt%; the support content is 92 wt%, the La2O3 content is 3%, the Na2O content is 0.1 wt%, and the BaO content is 2 wt%, with a specific surface area of ​​50 m². 2 / g, with a particle size of 4μm.

[0036] Preparation method:

[0037] 1. Pt(NO3)2, Ir(NO3)3, Ba(NO3)2, La(NO3)3, and NaNO3 solution were loaded onto CeO2 by an equal-volume impregnation method. After drying and calcination, catalyst powder was obtained. Water and aluminum sol were added to the catalyst powder, and the mixture was ground to form a slurry. The slurry was coated onto a honeycomb ceramic substrate, and after drying and calcination, a honeycomb catalyst was obtained.

[0038] Example 2

[0039] This embodiment provides a Pd / Al-based honeycomb monolithic catalyst with a Pd content of 2wt%, an Al2O3 support of 95wt%, and Pr6O4. 11 The dosage is 2%, K₂O is 0.1wt%, BaO is 0.9wt%, and its specific surface area is 200m². 2 / g, with a particle size of 3μm. The catalyst preparation method in this example is the same as in Example 1; subsequent examples will all use the same preparation method as in Example 1 by default.

[0040] Example 3

[0041] This embodiment provides a Ru / Ce-Al honeycomb monolithic catalyst with a Ru content of 5 wt%, a CeO2 content of 38 wt%, an Al2O3 content of 54 wt%, a Y2O3 content of 2%, a Na2O content of 0.1 wt%, a K2O content of 0.1 wt%, a BaO content of 0.8%, and a specific surface area of ​​120 m².2 / g, with a particle size of 4.5μm.

[0042] Example 4

[0043] A Pt-Pd-Ru-Ir / Ce honeycomb monolithic catalyst with Pt content of 0.5wt%, Pd content of 0.1wt%, Ru content of 1.4wt%, and Ir content of 2.0wt% has a CeO2 content of 91wt%, MgO content of 4%, BaO content of 1.0wt%, and a specific surface area of ​​200m². 2 / g, with a particle size of 5μm.

[0044] Example 5

[0045] A Pt / Al granular catalyst with a Pt content of 5 wt%, comprising 90 wt% Al₂O₃, 4% ZrO₂, and 1.0 wt% NaO, has a specific surface area of ​​500 m². 2 / g, with a particle size of 5μm.

[0046] Example 6

[0047] A Pt-Pd-Ru / Ce plate-shaped monolithic catalyst with Pt content of 0.5wt%, Pd content of 0.1wt%, and Ru content of 3.4wt% has a CeO2 content of 87wt%, ZrO2 content of 8%, BaO content of 1.0wt%, and a specific surface area of ​​200m². 2 / g, with a particle size of 5μm.

[0048] Comparative Example 1

[0049] This comparative example provides a NiO / Al2O3 honeycomb monolithic catalyst with a NiO content of 20 wt%; the Al2O3 support content is 77.9 wt%, the Na2O content is 0.1 wt%, the BaO content is 2 wt%, and the specific surface area of ​​its Al2O3 is 105 m². 2 / g, with a particle size of 4μm.

[0050] Preparation method:

[0051] Ni(NO3)2, Ba(NO3)2 and NaNO3 solutions were loaded onto CeO2 by an equal-volume impregnation method. After drying and calcination, catalyst powder was obtained. Water and aluminum sol were added to the catalyst powder, and the mixture was ground into a slurry. The slurry was coated onto a honeycomb ceramic substrate, and after drying and calcination, a honeycomb catalyst was obtained.

[0052] Comparative Example 2

[0053] This comparative example provides a Pt-Ir / Ce honeycomb monolithic catalyst with a Pt content of 0.4 wt% and an Ir content of 2.5 wt%; the support content is 95 wt%, the Na₂O content is 0.1 wt%, and the BaO content is 2 wt%, with a specific surface area of ​​50 m². 2 / g, with a particle size of 4μm.

[0054] Preparation method:

[0055] Pt(NO3)2, Ir(NO3)3, Ba(NO3)2, and NaNO3 solution were loaded onto CeO2 by an equal-volume impregnation method. After drying and calcination, catalyst powder was obtained. Water and aluminum sol were added to the catalyst powder, and the mixture was ground to form a slurry. This slurry was coated onto a honeycomb ceramic substrate, and after drying and calcination, a honeycomb catalyst was obtained.

[0056] Comparative Example 3

[0057] This comparative example provides a Pt-Ir / Ce honeycomb monolithic catalyst with a Pt content of 0.4 wt% and an Ir content of 2.5 wt%; the support content is 95.1 wt%, the La2O3 content is 3%, and its specific surface area is 50 m². 2 / g, with a particle size of 4μm.

[0058] Preparation method:

[0059] Pt(NO3)2, Ir(NO3)3 and La(NO3)3 solutions were loaded onto CeO2 by an equal-volume impregnation method. After drying and calcination, catalyst powder was obtained. Water and aluminum sol were added to the catalyst powder, and the mixture was ground to form a slurry. This slurry was coated onto a honeycomb ceramic substrate, and after drying and calcination, a honeycomb catalyst was obtained.

[0060] Table 1 summarizes the components of each embodiment.

[0061]

[0062] The catalysts obtained in Examples 1-6 above were subjected to aging treatment, and activity tests were performed on fresh and aged samples. Specifically, the aging conditions were: aging atmosphere of CH4 25% and H2O 75%, and space velocity of 1000 h⁻¹. -1 The catalyst was continuously aged at 950℃ for 20 hours. The test conditions were: a test atmosphere of 25% CH4 and 75% H2O, and a space velocity of 2000 h⁻¹. -1 The catalyst was continuously tested at 550℃, 600℃, 700℃, 750℃, 800℃, and 900℃ for 10 hours. The conversion rate of CH4 by the catalyst is shown in Table 2. Figure 1 and Figure 2The conversion curves of CH4 for fresh and aged catalyst samples are shown below:

[0063] Table 2 summarizes the CH4 conversion data of the catalysts in Examples 1-6 (550℃).

[0064]

[0065]

[0066] In this invention, by optimizing the structure of the natural gas reforming catalyst and using a noble metal with higher adsorption activity for natural gas cracking as the active material, the operating temperature of the catalyst is significantly reduced. At least one of alumina and oxygen storage materials is used as a support to disperse the noble metal; through the synergistic effect of the support and the noble metal, its catalytic activity is further enhanced. Due to the high price of noble metals, this invention controls the amount of noble metal used to within 5%, and the amount of support is 40-95%.

[0067] During catalyst structure optimization, the synergistic effect of adding structural and activating agents on the precious metal components effectively improves the catalyst's high-temperature resistance, ensuring it remains activated even under prolonged high-temperature conditions (30,000 hours). This also reduces carbon buildup during the reforming process and extends the catalyst's lifespan.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A natural gas steam reforming catalyst, characterized in that, It includes a noble metal active component and a carrier material, wherein the noble metal active component is at least one or a combination of two of Pt, Pd, Ru, and Ir, and the content of the noble metal active component is 0.1-5 wt%. The carrier material comprises at least one or a combination of two of alumina, oxygen storage material, or SBA-15 molecular sieve, wherein the content of the carrier material is 87-95 wt%, and the content of the oxygen storage material CeO2 is 10-60 wt%; the specific surface area of ​​the carrier material ranges from 60 to 200 m². 2 / g; It also includes structural additives, which include metal oxides of any one of the metals La, Pr, Zr, Y, and Mg, and the content of the structural additives is 2-8 wt%. It also includes an active ingredient, which includes at least one selected from Na₂O, K₂O, BaO, CaO, and MgO, and the content of the active ingredient is 0.1-5 wt%. The natural gas steam reforming catalyst is prepared by an equal-volume impregnation method, specifically including the following steps: S1. Pretreatment is performed by adding an organic compound with carboxyl or amine groups as a dispersant to a salt solution containing precious metal active components. S2. The metal salt solution of structural additives and active additives is loaded onto the support material by equal volume impregnation method, and then dried and calcined to obtain catalyst powder. S3. Add water and aluminum sol to the catalyst powder, grind it into a slurry, coat it onto a honeycomb ceramic substrate, dry it, and calcine it to obtain the honeycomb catalyst.

2. The natural gas steam reforming catalyst according to claim 1, characterized in that, The amount of impregnation solution used is 0.3-10 times the volume of the water pores in the carrier material.

3. The natural gas steam reforming catalyst according to claim 1, characterized in that, The drying temperature range is 60-300℃, and the calcination temperature is 200-1000℃.

4. The natural gas steam reforming catalyst according to claim 1, characterized in that, The particle size of the natural gas steam reforming catalyst is 0.5-500 μm.

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