CO2 methanation catalyst, preparation method and application thereof, and application of obtained methane

Abstract

The invention belongs to the technical field of carbon dioxide methanation, and particularly relates to a carbon dioxide methanation catalyst, a preparation method and application thereof and application of an obtained methane product. The carbon dioxide methanation catalyst comprises a composite carrier and nickel oxide serving as an active component, the composite carrier is a compound of mesoporous silica and metal oxide; the metal oxide is selected from cerium oxide and / or calcium oxide; in the composite carrier, the content of cerium oxide is 10-70 wt%, and the content of calcium oxide is 10-25 wt%. The preparation method of the catalyst comprises the following steps: preparing a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer into an aqueous solution, adding soluble cerium salt or calcium salt, uniformly stirring, adding a hydrochloric acid aqueous solution, and drying and calcining a product to obtain a porous composite carrier; and dissolving a soluble nickel precursor salt in ethanol, adding the porous composite carrier, and dispersing to obtain the NiO-loaded catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide methanation, and in particular relates to a carbon dioxide methanation catalyst, a preparation method and application thereof, and application of the obtained methane product. Background Art

[0002] As a green and efficient secondary energy carrier, hydrogen has the characteristics of abundant sources, light weight, high calorific value, green and environmental protection, and various forms of utilization and storage. It can not only meet human needs for low-carbon development, but also play an important role in the future energy layout. It is also of great significance to build a green, low-carbon, safe and efficient energy system and achieve the dual carbon goals of carbon peak and carbon neutrality. A large number of domestic scholars have conducted research and analysis on the mixing of hydrogen into natural gas (methane) pipelines for mixed hydrogen transportation. The results show that the mixing of low-concentration hydrogen into natural gas (methane) pipelines will not affect the natural gas pipeline system and process, highlighting the possibility of natural gas (methane) mixed with hydrogen for hydrogen transportation. However, there is almost no natural gas (methane) in places where green hydrogen is produced by renewable electricity, and it is difficult to achieve hydrogen transportation by mixing natural gas (methane) with hydrogen.

[0003] Sabatier et al. discovered CO in 1902 2 Methanation reaction. In the context of carbon neutrality, through CO 2 Capture and storage or CO 2 Conversion into useful fuels or chemicals is the key to achieving CO 2 An effective means of emission reduction and recycling. Among them, methane is a clean fuel and an important new C1 basic chemical raw material with huge market demand. With the rapid development of renewable energy, green hydrogen will gradually become the mainstream of hydrogen source. CO captured from industrial or coal-fired power exhaust and atmosphere 2 After adding green hydrogen to convert it into green methane, it can be directly injected into the natural gas pipeline, realizing the interconnection between the power grid and the natural gas pipeline network and CO 2 Recycling can meet my country's growing energy and carbon reduction needs. 2 Catalytic hydrogenation to produce CH 4 (Methanation) is expected to become a promising and sustainable technology route.

[0004] CO 2 The chemical inertness of CO is very high, and activation often needs to be achieved at high temperatures, which consumes a lot of energy. 2 Methanation is a spontaneous and highly exothermic reaction. Lower temperatures are conducive to methanation and prevent side reactions. Therefore, the development of low-temperature and high-efficiency CO 2 Methanation catalysts are of great significance.

[0005] Carbon dioxide methanation is a chemical process achieved by the reduction reaction of carbon dioxide and green hydrogen through a catalyst bed. The catalyst used can be selected from different carriers (for example, cerium dioxide composite mesoporous SBA-15 can be used as a carrier) and prepared by loading ruthenium, cobalt, platinum, rhodium, palladium, iron, nickel, etc.

[0006] Noble metals such as Rh, Ru, and Pd have excellent activity and CH 4 Selectivity is often considered for CO 2 Compared with precious metal catalysts, Ni-based catalysts are increasingly used in CO methanation due to their low price and excellent catalytic activity and selectivity. 2 Methanation reaction.

[0007] Carbon dioxide methanation and its selected catalysts and other related technologies are described in the scientific literature - "Nickel-based catalysts for the catalytic conversion of CO 2 Progress in Methanation Reaction Research" and scientific literature - "CO 2 These issues are all involved in the "Research Progress of Nickel-Based Methanation Catalysts", and the advantages and disadvantages of catalysts prepared by different carriers and active components are reviewed.

[0008] Scientific and technological literature - "Nickel-based catalysts for the catalysis of CO 2 The progress of methanogenic reaction research reported that high CO 2 Conversion rate and 100% CH 4 Selective methanation can be achieved, but the use of nitrogen to dilute the reaction gas makes the methanation efficiency low, and the need to separate the products will inevitably lead to higher energy consumption.

[0009] Scientific and technological literature - CO 2 The progress of nickel-based catalysts for methanation reported that high CO 2 Conversion rate and 100% CH 4 Selective methanation, however, has a very narrow high-performance temperature range for methanation and a small reaction gas volume, resulting in significantly low efficiency.

[0010] Lower methanation temperature is beneficial to the reaction, while the product CH 4 The selectivity will also be improved accordingly. However, the current methanation temperature is still generally high, and the operating temperature range is narrow, which is not conducive to the control of the exothermic methanation reaction process. Therefore, it is necessary to develop low-temperature and high-efficiency catalysts, especially Ni-based catalysts, for CO 2 Methanation is of great importance. Summary of the invention

[0011] The purpose of the present invention is to provide a carbon dioxide methanation catalyst and its preparation method and application, as well as the application of the obtained methane product, in view of the problem that the current methanation temperature is generally high and the operating temperature range is narrow. The methanation catalyst is applied to the carbon dioxide methanation reaction, and the selectivity of the obtained methane product can reach 100%, the carbon dioxide conversion rate remains high, the methanation operating temperature is low and the temperature range is wide, and it is expected that the methanation technology can be realized by using industrial waste heat; and the methanation system can utilize carbon dioxide generated or captured by biomass combustion to react with green hydrogen, and while storing green hydrogen, it can realize the transportation of green hydrogen in places without natural gas, thereby solving the bottleneck problem of hydrogen storage and blending in the hydrogen energy industry chain.

[0012] In order to achieve the above object, the present invention provides the following technical solutions:

[0013] In a first aspect, a carbon dioxide methanation catalyst is provided, comprising: a composite carrier and nickel oxide as an active component;

[0014] The composite carrier is a composite of mesoporous silica and metal oxide; the metal oxide is selected from cerium oxide and / or calcium oxide.

[0015] According to the catalyst provided by the present invention, in some embodiments, the composite carrier is a composite of mesoporous silica and cerium oxide, or a composite of mesoporous silica and calcium oxide.

[0016] In some embodiments, based on the total weight of the composite carrier, the content of cerium oxide in the composite of mesoporous silica and cerium oxide is 10-70wt% (for example, 12wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 45wt%, 50wt%, 60wt%), preferably 10-40wt%.

[0017] In some embodiments, based on the total weight of the composite carrier, the content of calcium oxide in the composite of mesoporous silica and calcium oxide is 10-25wt% (e.g., 12wt%, 14wt%, 15wt%, 16wt%, 18wt%, 22wt%), preferably 10-20wt%.

[0018] In some embodiments, the mesoporous silica has a pore size ranging from 5 to 10 nm (e.g., 6 nm, 8 nm); a pore volume ranging from 0.5 to 0.9 cm 3 g -1 (For example, 0.55 cm 3 g -1 、0.6cm 3 g -1 、0.8cm 3 g -1).

[0019] In some embodiments, the nickel oxide loading is 10-40 wt% (e.g., 12 wt%, 15 wt%, 20 wt%, 25 wt%, 28 wt%, 32 wt%, 35 wt%), preferably 10-30 wt%, based on the total weight of the catalyst.

[0020] In a second aspect, a method for preparing the carbon dioxide methanation catalyst as described above is provided, comprising the following steps:

[0021] (1) at room temperature, dissolving a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer (abbreviated as P123) in water to prepare an aqueous solution, adding a soluble cerium salt or calcium salt to dissolve the mixture, adding tetraethyl orthosilicate, stirring the mixture evenly, and then adding a hydrochloric acid aqueous solution to carry out a heating reaction; after the reaction is completed, filtering and washing the solid product with water, drying and calcining the solid product to obtain a porous composite support of mesoporous metal oxide-SBA-15;

[0022] (2) dissolving a soluble nickel precursor salt in an alcohol solvent, adding the porous composite support obtained in step (1) and performing a dispersion treatment; after the treatment, volatilizing the solvent and calcining to obtain a NiO-loaded catalyst; the alcohol solvent is preferably a monohydric alcohol, more preferably ethanol.

[0023] According to the preparation method provided by the present invention, the carbon dioxide methanation catalyst as described in the first aspect above is prepared.

[0024] According to the preparation method provided by the present invention, in some embodiments, the soluble cerium salt or calcium salt can be, but is not limited to, cerium nitrate, cerium chloride, calcium nitrate, calcium chloride, or hydrates thereof.

[0025] In some embodiments, the soluble nickel precursor salt may be, but is not limited to, nickel nitrate, nickel chloride, nickel sulfate, or hydrates thereof.

[0026] According to the preparation method provided by the present invention, in some embodiments, in step (1), the process conditions of the heating reaction include: the reaction temperature is 60-100°C (for example, 65°C, 80°C, 90°C), and the reaction time is 12-48h (for example, 16h, 20h, 30h, 40h).

[0027] In some embodiments, in step (1), the molar ratio of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer:ethyl orthosilicate is 1:(55-61), for example, 1:58, 1:59, 1:60.

[0028] In some embodiments, in step (1), the molar ratio of tetraethyl orthosilicate: cerium in a soluble cerium salt is 1:(0.03-0.3), for example, 1:0.035, 1:0.039, 1:0.045, 1:0.06, 1:0.08, 1:0.1, 1:0.15, 1:0.2, 1:0.25, preferably 1:(0.05-0.23).

[0029] In some embodiments, in step (1), the molar ratio of tetraethyl orthosilicate: calcium in a soluble calcium salt is 1:(0.12-0.46), for example, 1:0.14, 1:0.18, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, preferably 1:(0.15-0.3).

[0030] In some embodiments, in step (1), the molar ratio of tetraethyl orthosilicate to the solute in the hydrochloric acid aqueous solution can be 1:(5-7), for example, 1:5.5, 1:6, 1:6.5, 1:6.9.

[0031] The concentration of the aqueous hydrochloric acid solution may be, for example, 35-40 wt%, such as 36 wt%, 38 wt%.

[0032] In some embodiments, in step (1), the process steps and conditions for drying and calcining the solid product are conventional operations in the art and are not described here. For example, the solid product is dried at 60-100°C (e.g., 80°C, 90°C) for 1-3h (e.g., 2h), or vacuum dried at 60-100°C (e.g., 80°C, 90°C) for 1-3h (e.g., 2h). The calcination temperature is, for example, 400-550°C, and the calcination time is 1-6h (e.g., 3h, 4h, 5h).

[0033] In some embodiments, the amount of water or deionized water in the aqueous solution prepared in step (1) is expressed as the concentration of the solute in the aqueous solution; for example, the concentration of the polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer in the aqueous solution can be 0.5-5wt% (e.g., 0.6wt%, 1wt%, 2wt%, 3wt%, 4wt%). The concentration of the soluble cerium salt or calcium salt in the aqueous solution can be 0.28-5.8wt% (e.g., 0.4wt%, 0.8wt%, 1.5wt%, 2wt%, 4wt%, 5wt%). The concentration of the hydrochloric acid aqueous solution can be, for example, 35-37wt%.

[0034] In some embodiments, in step (2), the process conditions of the dispersion treatment include: the treatment temperature is room temperature to 40°C (e.g., 25°C, 30°C, 35°C), and the treatment time is 0.5-2h (e.g., 1h, 1.5h);

[0035] In some embodiments, in step (2), the weight ratio of the nickel precursor salt to the porous composite support is 1:(0.5-10), for example, 1:0.6, 1:0.8, 1:0.9, 1:1, 1:2, 1:4, 1:5, 1:6, 1:8, preferably 1:(3-9).

[0036] In some embodiments, in step (2), the processes of solvent evaporation and calcination are conventional operations in the art and are not described in detail here. For example, the solvent can be evaporated by heating. The calcination temperature is, for example, 400-550° C. (e.g., 450° C., 500° C.); the calcination time is, for example, 1-6 h (e.g., 3 h, 4 h, 5 h).

[0037] In some embodiments, in step (2), the mass ratio of the soluble nickel precursor salt to ethanol can be, for example, 1:(2-8), such as 1:4, 1:5, or 1:6.

[0038] In a third aspect, a catalyst as described above or a catalyst prepared by the preparation method as described above is provided for use in a carbon dioxide methanation reaction.

[0039] In some embodiments, the process conditions for the carbon dioxide methanation reaction include: the reaction pressure is normal pressure, the reaction temperature is 260-360° C. (e.g., 270° C., 300° C., 320° C., 350° C.), preferably 280-340° C.; the reaction gas is H 2 With CO 2 The reaction gas is H 2 / CO 2 Volume ratio, H 2 / CO 2 =4, volume space velocity is 1000-10000h -1 , for example, 1200h -1 , 1400h -1 、1500h -1 、2000h -1 、3000h -1 , 4000h -1 , 5000h -1 、6000h -1 、8000h -1 , 9000h -1 、9500h -1 .

[0040] In the carbon dioxide methanation reaction, CO 2 They come from a variety of sources, for example, power plants, capture plants or biomass burning.

[0041] In a fourth aspect, there is provided a use of a methane product obtained by the methanation reaction of carbon dioxide as described above in hydrogen storage, hydrogen blending or hydrogen transport.

[0042] Hydrogen storage and transportation system: Methane products can produce hydrogen through steam reforming or pyrolysis.

[0043] Hydrogen storage and transportation system: After the methane product is mixed with hydrogen and transported to the destination, it can be burned to generate electricity or provide heat source, or it can be separated to provide hydrogen.

[0044] The present invention provides a method having high CO in a relatively wide temperature range of 280-360°C. 2 Conversion rate and 100% CH 4 Selective methanation technology solution. That is, by loading nickel oxide on a composite carrier of mesoporous silica and metal oxides, and selecting the ratio of silica and metal oxides, a catalyst with improved catalytic performance for carbon dioxide methanation can be obtained. When the catalyst is used in the carbon dioxide methanation process, the methanation process does not need to use other gases to dilute the reaction gas, does not require product separation engineering, and has a large reaction gas volume and high reaction efficiency, achieving high CO in a relatively wide temperature range of 280-360°C. 2 Conversion rate and 100% CH 4 Selective.

[0045] The methanation technology provided by the present invention has a low operating temperature, and thus the methanation process can be realized by utilizing residual heat, waste heat, etc.

[0046] The methanation technology solution of the present invention provides hydrogen-blended natural gas for the hydrogen transmission system, solving the problem of green hydrogen transportation in areas without natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 (A1)-(A2) show the composite support (CeO 2 -SiO 2 ) XRD pattern of supported NiO catalyst;

[0048] Figure 2 (A1)-(A2) show the composite support (CaO-SiO 2 ) The methanation results of NiO-supported catalyst (NiO: 10 wt%) are shown in Figure 2.

[0049] Figure 3 A schematic diagram of hydrogen storage and hydrogen blending and transmission using carbon dioxide methanation products is shown. DETAILED DESCRIPTION

[0050] In order to understand the technical features and contents of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described here.

[0051] <Source of raw materials>

[0052] The reagents used in the following examples and comparative examples without indicating the manufacturer are all conventional products that can be purchased from the market.

[0053] Polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer (P123) was purchased from a commercial source.

[0054] Tetraethyl orthosilicate, purchased from commercial sources.

[0055] Cerium nitrate or its hydrate, calcium nitrate or its hydrate, and nickel nitrate or its hydrate are all commercially available.

[0056] 1. Preparation of Catalyst

[0057] Catalyst Preparation Comparative Example 1:

[0058] The catalyst of NiO supported by SBA-15 porous carrier is prepared by:

[0059] (1) At room temperature, 4 g of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer (abbreviated as P123) was dissolved in distilled water to prepare an aqueous solution with a concentration of 3.7 wt%, and then 8.52 g of tetraethyl orthosilicate was added and stirred evenly, and then 28.6 g of a 36 wt% hydrochloric acid aqueous solution (i.e., the mass of HCl solute in the aqueous solution was 10.3 g) was added, and then heated to react; wherein, the reaction temperature was 80°C and the reaction time was 24 h; after the reaction was completed, the solid product was filtered and washed with water, and then dried at 80°C for 2 h and calcined at 550°C for 5 h to obtain a mesoporous SBA-15 porous body carrier; its pore diameter was 6.83 nm and the pore volume was 0.86 cm 3 g -1 .

[0060] (2) 2.92 g of nickel nitrate hexahydrate was dissolved in an ethanol solvent to prepare an ethanol solution with a concentration of 14.2 wt%, and 3 g of the mesoporous SBA-15 porous body carrier prepared in step (1) was added to the solution for dispersion treatment at room temperature for 1 h. After the dispersion was completed, the solvent was evaporated and the solution was calcined at 500° C. for 3 h to obtain a NiO-loaded SBA-15 porous body catalyst.

[0061] Catalyst Preparation Comparative Example 2:

[0062] CeO 2The catalyst of NiO supported by the carrier is prepared by:

[0063] 2.92 g of nickel nitrate hexahydrate was dissolved in ethanol solvent to prepare an ethanol solution with a concentration of 14.2 wt%, and then 3 g of CeO 2 The dispersion treatment was carried out at room temperature for 1 h. After the dispersion was completed, the solvent was evaporated and calcined at 500 °C for 3 h to obtain NiO-loaded CeO 2 catalyst.

[0064] Catalyst Preparation Comparative Example 3:

[0065] The catalyst of CaO carrier supporting NiO is prepared by:

[0066] 2.92 g of nickel nitrate hexahydrate was dissolved in an ethanol solvent to prepare an ethanol solution with a concentration of 14.2 wt%, and then 3 g of CaO was added to perform dispersion treatment at room temperature for 1 hour. After the dispersion was completed, the solvent was evaporated and calcined at 500° C. for 3 hours to obtain a NiO-loaded CaO catalyst.

[0067] Catalyst Preparation Examples 1-10:

[0068] The catalyst of NiO supported by a metal oxide-SBA-15 composite porous body carrier is prepared by:

[0069] (1) At room temperature, 4 g of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer (abbreviated as P123) was dissolved in distilled water to prepare a 3.7 wt% aqueous solution, cerium nitrate hexahydrate or calcium nitrate tetrahydrate was added to dissolve, and then 8.52 g of tetraethyl orthosilicate was added and stirred evenly, and then 28.6 g of a 36 wt% aqueous hydrochloric acid solution (i.e., the mass of HCl solute in the aqueous solution was 10.3 g) was added, and then heated to react; wherein the reaction temperature was 80°C and the reaction time was 24 h; after the reaction was completed, the solid product was filtered and washed with water, and then dried at 80°C for 2 h and calcined at 550°C for 5 h to obtain a porous composite carrier of mesoporous metal oxide-SBA-15;

[0070] (2) Nickel nitrate hexahydrate was dissolved in an ethanol solvent to prepare an ethanol solution with a concentration of 1.5, and the porous composite support of the mesoporous metal oxide-SBA-15 prepared in step (1) was added to perform dispersion treatment at room temperature for 1 hour. After the dispersion was completed, the solvent was evaporated and calcined at 500° C. for 3 hours to obtain a metal oxide-SBA-15 porous body catalyst loaded with NiO, the composition of which is shown in Table 1. The formula of each raw material in the catalyst preparation process is shown in Table 2.

[0071] Catalyst Preparation Comparative Example 4:

[0072] The preparation process of the catalyst refers to the steps of Preparation Example 9, except that the proportion of calcium oxide in the composite carrier is 30wt%. The formula of each raw material in the catalyst preparation process is shown in Table 2.

[0073] Table 1 Composition of the catalysts obtained in each preparation example and preparation comparative example

[0074]

[0075] Note: In the catalyst composition shown in Table 1, except for the NiO loading, the remainder is the carrier or composite carrier.

[0076] Table 2 Raw material composition formula during catalyst preparation

[0077]

[0078]

[0079] 2. CO 2 Performance evaluation of methanation reactions

[0080] A 6.28 cm 3 Each catalyst prepared as above was fixed at both ends with quartz wool, and a temperature sensor was inserted in the center of the catalyst to monitor the reaction temperature. Before evaluating the methanogenic reaction performance, each catalyst was reduced at 500°C for 5 hours using a mixture of 40 ml / min hydrogen and 10 ml / min nitrogen. 2 :CO 2 =4:1) the reaction gas enters the reactor at a flow rate of 150 ml / min, and the volume space velocity is 1400 h -1 , the methanation performance of each catalyst prepared was evaluated; wherein, the reaction temperature was 240°C-440°C, the catalytic effect at the reaction temperature of 280°C-360°C was observed and the results were recorded, as shown in Table 3-5.

[0081] Table 3 Methanation performance evaluation results when the methanation reaction temperature is 280°C

[0082]

[0083]

[0084] Table 4 Methanation performance evaluation results when the methanation reaction temperature is 320°C

[0085] serial number <![CDATA[CO 2 Conversion rate / %]]> Methane selectivity / % Preparation Example 1 73 99.4 Preparation Example 2 74 100 Preparation Example 3 75 100 Preparation Example 4 77 100 Preparation Example 5 84 100 Preparation Example 6 84 100 Preparation Example 7 74 100 Preparation Example 8 78 100 Preparation Example 9 79.6 100 Preparation Example 10 80 100 Preparation Comparative Example 1 44 98.1 Preparation Comparative Example 2 32 70 Preparation Comparative Example 3 12 49 Preparation Comparative Example 4 44 98.1

[0086] Table 5 Methanation performance evaluation results when the methanation reaction temperature is 340°C

[0087]

[0088]

[0089] From the experimental results in Table 3-5, we can see that:

[0090] For the composite support (CeO 2 -SiO 2 ) loaded with NiO catalyst, CeO 2 The content is controlled to be 10-40wt%, and as CeO 2 The increase in carbon dioxide content, the low temperature zone of carbon dioxide methanation reaction (e.g., 280-360℃), CO 2 Conversion rate and CH 4 The selectivity increases; when CeO 2 When the content reaches 20wt% or more, CH 4 The selectivity can reach 100% below 340°C.

[0091] For the composite support (CeO 2 -SiO 2 , where CeO 2 :40wt%) loaded with different NiO contents, with the increase of NiO content, CO2 methanation reaction in low temperature zone (e.g., 280-360℃), CO 2 Conversion rate and CH 4 The selectivity increased; when the NiO content was 20wt% and 30wt%, CO 2 The conversion rate did not change; when the NiO content reached above 20wt%, CH 4 The selectivity can reach 100% below 360°C.

[0092] For the composite support (CaO-SiO 2 ) supported NiO catalyst, the CaO content in the composite carrier is controlled at 10-20wt%. As the CaO content increases, the CO2 methanation reaction in the low temperature zone (e.g., 280-360°C) 2 Conversion rate and CH 4 The selectivity increased when the CaO content was 10wt% compared with 20wt%, CO 2 The conversion rate does not change much; when the CaO content reaches more than 10wt%, CH 4 The selectivity can reach 100% below 340°C.

[0093] For the composite support (CaO-SiO 2, wherein CaO: 20wt%) supported catalysts with different NiO contents, with the increase of NiO content, the low temperature zone (e.g., 280-360°C) of CO2 methanation reaction, CO 2 Conversion rate and CH 4 Increased selectivity.

[0094] The catalysts prepared in Examples 1-3 all used a single carrier loaded with NiO. In the low temperature region (e.g., 280-360°C) of the carbon dioxide methanation reaction, CO 2 Conversion rate and CH 4 In addition, at the same NiO loading, when the CaO content in the composite carrier exceeds 20wt%, CH 4 The selectivity decreases and is less than 100%.

[0095] pass Figure 1 (A1)-(A2) shows that the composite support (CeO 2 -SiO 2 ) in the NiO-supported catalyst, the catalyst has a regular and orderly mesoporous structure. The wide-angle XRD diffraction pattern on the right clearly shows that CeO 2 and characteristic peaks of NiO.

[0096] pass Figure 2 (A1)-(A2) also show that the composite supports with different CaO contents (CaO-SiO 2 ) Changing trend of methanation results of NiO-supported catalyst (NiO: 10wt%).

[0097] pass Figure 3 It can be seen that the methane product obtained from the methanation reaction of carbon dioxide can be used as a hydrogen storage carrier, or it can be mixed with hydrogen to transport hydrogen; after reaching the destination, hydrogen is released through steam reforming or hydrogen and methane are separated to utilize hydrogen energy, or the mixture of methane and hydrogen can be used as fuel and burned for energy or to generate electricity.

[0098] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A carbon dioxide methanation catalyst, characterized in that: It includes: A composite support and nickel oxide as an active component; The composite carrier is a composite of mesoporous silica and metal oxide; the metal oxide is selected from cerium oxide and / or calcium oxide.

2. The carbon dioxide methanation catalyst according to claim 1, characterized in that The composite carrier is a composite of mesoporous silica and cerium oxide, or a composite of mesoporous silica and calcium oxide; Based on the total weight of the composite carrier, the content of cerium oxide in the composite of mesoporous silica and cerium oxide is 10-70wt%, preferably 10-40wt%; and / or Based on the total weight of the composite carrier, the content of calcium oxide in the composite of mesoporous silica and calcium oxide is 10-25wt%, preferably 10-20wt%.

3. The carbon dioxide methanation catalyst according to claim 1 or 2, characterized in that: The pore size of the mesoporous silica is in the range of 5-10 nm and the pore volume is in the range of 0.5-0.9 cm 3 g -1 .

4. The carbon dioxide methanation catalyst according to any one of claims 1 to 3, characterized in that Based on the total weight of the catalyst, the loading amount of the nickel oxide is 10-40wt%, preferably 10-30wt%.

5. The method for preparing a carbon dioxide methanation catalyst according to claim 1, characterized in that: The steps include: (1) dissolving a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer in water to prepare an aqueous solution, adding a soluble cerium salt or calcium salt to dissolve the mixture, adding tetraethyl orthosilicate, stirring the mixture evenly, and then adding a hydrochloric acid aqueous solution to carry out a heating reaction; after the reaction is completed, filtering and washing the solid product with water, drying and calcining the solid product to obtain a porous composite carrier of mesoporous metal oxide-SBA-15; (2) dissolving a soluble nickel precursor salt in an alcohol solvent, adding the porous composite support obtained in step (1) and performing a dispersion treatment; after the treatment, volatilizing the solvent and calcining to obtain a NiO-loaded catalyst; the alcohol solvent is preferably a monohydric alcohol, more preferably ethanol; Preferably, the NiO-loaded catalyst is the carbon dioxide methanation catalyst according to any one of claims 2-4.

6. The preparation method according to claim 5, characterized in that: In step (1), the process conditions of the heating reaction include: reaction temperature of 60-100° C., and reaction time of 12-48 h.

7. The preparation method according to claim 5, characterized in that: In step (1), The molar ratio of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock polymer:ethyl orthosilicate is 1:(55-61); The molar ratio of tetraethyl orthosilicate to cerium in the soluble cerium salt is 1:(0.03-0.3), preferably 1:(0.05-0.23); The molar ratio of tetraethyl orthosilicate: calcium in the soluble calcium salt is 1:(0.12-0.46), preferably 1:(0.15-0.3).

8. The preparation method according to claim 5, characterized in that: In step (2), the process conditions of the dispersion treatment include: the treatment temperature is room temperature to 40° C., and the treatment time is 0.5-2 h; In step (2), the weight ratio of the nickel precursor salt to the porous composite carrier is 1:(0.5-10), preferably 1:(3-9).

9. The catalyst according to any one of claims 1 to 4 or the catalyst prepared by the preparation method according to any one of claims 5 to 8 is used in the methanation reaction of carbon dioxide; Preferably, the process conditions for the carbon dioxide methanation reaction include: The reaction temperature is 260-360°C, preferably 280-340°C; the reaction gas is a mixture of H2 and CO2, in which H2 / CO2=4; the volume space velocity is 1000-10000h -1 .

10. Use of the methane product obtained by the methanation reaction of carbon dioxide as claimed in claim 9 in hydrogen storage, hydrogen blending or hydrogen transportation.

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