WO2021042874A1 - Nickel-based catalyst for carbon dioxide methanation, preparation method therefor and application thereof - Google Patents

Abstract

A supported nickel-based catalyst for carbon dioxide methanation reaction. The supported nickel-based catalyst is a mixed oxide composed of the following components by weight parts: 3 parts of nickel oxide, 4-6 parts of metal oxide support, and 1-3 parts of doped metal oxide. A doped modified support is used for the catalyst; compared with the solution using a single support, the methane yield is greatly increased while maintaining a high selectivity, especially in the low temperature section (250°C), the increase rate exceeds 100%, and the methane yield is up to 78%. In addition, the stability of the catalyst is also higher than that of the catalyst with cerium oxide as the support, so that the bottleneck of inability of realizing high activity, selectivity, and stability of the existing catalytic system is overcome. The catalyst can be prepared by means of co-precipitation; the method is simple, and the cerium/yttrium ratio is adjustable. The present application is suitable for large-scale industrial production.

Description

Nickel-based catalyst for carbon dioxide methanation and preparation method and application thereof Technical field

The invention relates to a catalyst for methanation reaction, in particular to a nickel-based catalyst for carbon dioxide methanation, and a preparation method and application thereof.

Background technique

In recent years, with the large-scale exploitation and use of fossil fuels such as coal, oil, and natural gas, the concentration of carbon dioxide in the atmosphere has remained high and is still increasing year by year. The increase in carbon dioxide content in the atmosphere has led to the greenhouse effect and caused global climate changes, such as sea level rise and global warming. The development of carbon dioxide resource utilization technology is an effective solution to alleviate the pressure of carbon emissions. Among the many utilization technologies, carbon dioxide methanation is very attractive because of its high conversion rate, the large amount of surplus hydrogen produced by new energy technologies, and the complete storage and transportation facilities for product methane.

Methanation of carbon dioxide is a strong exothermic reaction, catalyzed by transition metals, especially group VIII metals with good catalytic activity. The catalysts reported in the current research mainly include metal catalysts based on ruthenium, rhodium, palladium and nickel. As precious metals, ruthenium, rhodium, and palladium are difficult to realize industrialization. The nickel-based catalyst has low cost and good activity, and has a good industrialization prospect.

The current research direction of nickel-based catalysts is mainly supported catalysts. There are many types of supports that can be used as nickel-based methanation catalysts. Cerium oxide is the one with better activity. There are oxygen vacancies on the surface of nickel/cerium oxide, which has good carbon dioxide adsorption capacity. According to the literature (Hiroki Muroyama et al. Journal of Catalysis 2016, 343, 178-184.), it is reported that the methane yield reaches 70%, and the selectivity is close to 100%.

However, the nickel/cerium oxide catalytic system is easy to sinter at high temperatures, and the stability needs to be improved, and the methane yield also has a large room for improvement. Therefore, there is an urgent need in the art to further improve the stability and activity of the nickel-based carbon dioxide methanation catalyst while maintaining high selectivity.

Summary of the invention

The purpose of the present invention is to provide a nickel-based catalyst for carbon dioxide methanation and a preparation method and application thereof in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

The supported nickel-based catalyst used for the methanation of carbon dioxide in the present invention is a mixed oxide composed of the following components by weight:

Nickel oxide 3;

Metal oxide carrier 4～6;

Doping with metal oxides 1-3.

Further, the metal oxide carrier is ceria.

Further, the doped metal oxide is yttrium trioxide.

The preparation method of the above-mentioned supported nickel-based catalyst in the present invention includes the following steps:

S1: Dissolve the metal salts of nickel, cerium and yttrium in water to obtain solution A;

S2: Add the carbonate solution to solution A, mix well, and let stand for 10-12 hours to obtain mixture B;

S3: Suction filtration, washing and drying of mixture B to obtain solid C;

S4: Grind the solid C into a powder, and calcinate it at 400-500°C for 3 to 5 hours to obtain a finished catalyst.

Further, the concentration of the carbonate solution is 0.5 mol/L.

Further, the carbonate solution is an ammonium carbonate solution.

Further, the metal salts of nickel, cerium and yttrium are all corresponding metal nitrates.

In the application of the supported nickel-based catalyst in the present invention, the reaction gas is contacted and reacted with the supported nickel-based catalyst under the conditions of a reaction temperature of 200-450°C, a reaction pressure of normal pressure, and a space velocity of 30000L/(kg·h) Methane.

Further, the reaction gas is a mixed gas composed of hydrogen, carbon dioxide and inert gas.

Further, the supported nickel-based catalyst is activated with a reaction gas for 2 to 3 hours before the reaction, and the activation temperature is 400 to 450 hours.

The results show that compared with the nickel-based catalysts with pure cerium oxide or pure yttrium oxide as the carrier _{, adding yttrium metal to Ni-CeO 2} can significantly increase the activity of the catalyst, not only greatly increase the conversion rate of carbon dioxide, but also increase methane. The selectivity of carbon monoxide also reduces the yield of carbon monoxide and increases the yield of methane.

As shown in the TEM (Figure 2) and XRD spectra (Figure 3), the addition of yttrium also changes the dispersion state of atoms on the catalyst surface, and the nickel particles become smaller, increasing the specific surface area, that is, increasing the active sites of the reaction. , Is conducive to the progress of the reaction.

From the H ₂ -TPR results (Figure 4), it can be seen that the addition of yttrium reduces the reduction temperature of the catalyst, strengthens the intensity of the reduction peak, constructs lattice defects, and improves the activity of oxygen atoms in the catalyst

From the BET specific surface area diagram before and after the reaction (Figure 5), it can be seen that the addition of yttrium improves the stability of the catalyst.

Compared with the prior art, the present invention has the following advantages:

1) The supported nickel-based catalyst synthesized by the present invention is added with doped yttrium metal. The basic sites of yttrium oxide enhance the ability of carbon dioxide adsorption, so that the catalyst has a higher methanation activity than cerium monooxide at the same temperature. On the basis of maintaining high selectivity, the activity of the carrier increases the methane yield by nearly 10% compared to the single carrier, and the highest is 78%. The stability of the catalyst is also higher than that when the cerium monooxide is the carrier. The activity and selectivity bottleneck of the existing catalytic system.

2) The catalyst of the present invention is prepared by co-precipitating nickel metal salt and a precursor of cerium/yttrium metal salt. The method is simple, the ratio of cerium/yttrium can be adjusted, and it can be applied to large-scale industrial production.

Description of the drawings

Figure 1 is an activity data diagram of each catalyst sample in the present invention;

Figure 2 is a TEM image of a 0.3NiO-0.3Y ₂ O ₃ -CeO ₂ catalyst sample in the present invention;

Figure 3 is an XRD pattern of each catalyst sample in the present invention;

_{Figure 4 is an H 2} -TPR diagram of each catalyst sample in the present invention;

Figure 5 is a BET diagram of each catalyst sample in the present invention.

detailed description

The present invention will be described in detail below with reference to the drawings and specific embodiments.

Example 1

The carbon dioxide methanation catalyst was prepared by the co-precipitation method using ammonium carbonate as the precipitant. By adding a certain amount of ammonium carbonate to the salt solution of nickel metal, cerium metal and yttrium metal at a certain rate, the reaction occurred and precipitated. After filtering, drying, grinding and calcining, the catalyst is obtained. By incorporating yttrium metal into the nickel-based catalyst, the activity and stability of the original nickel-based catalyst are improved.

In this example, _{the preparation of NiO-CeO 2} -Y ₂ O ₃ catalyst, the mass ratio NiO:CeO ₂ :Y ₂ O ₃ =3:6:1

making process:

S1: Dissolve 1.168g Ni(NO ₃ ) ₂ ·6H ₂ O, 1.479g Ce(NO ₃ ) ₃ ·6H ₂ O and 0.339g Y(NO ₃ ) ₃ ·6H ₂ O in 75ml deionized water, and stir magnetically To dissolve it

S2: Add 50 mL of 0.5 mol/L ammonium carbonate solution to the solution obtained in step S1, with a dropping rate of 1-2 mL/s;

S3: After continuing to stir the mixture obtained in step S2 for 30 minutes, let it stand for 12 hours;

S4: Suction filtration and washing of the mixture obtained in step S3, and the washing water volume is 300 mL;

S5: Put the solid material obtained in step S4 into a vacuum oven for 12 hours, and set the temperature to 60°C;

S6: Grind the solid obtained in step S5 into powder, and calcinate in a muffle furnace at 400-500° C. for 3-5 hours to obtain the final product.

Testing process:

Catalyst evaluation process:

S1: Put the prepared catalyst in a tubular reactor, the reactor inlet is connected to the reaction mixture, and the outlet is connected to the condenser.

S2: Open the valve and pass in the reaction mixture at a space velocity of 30000L/(kg·h). Heat the reactor to 400-450°C and activate it for 2-3 hours.

S3: Adjust the reaction temperature, and check the gas phase product composition every 20 minutes in the steady state.

The performance test of the catalyst in this experiment was carried out in a micro fixed-bed reactor. The application process for the carbon dioxide methanation catalyst was as follows: Weigh 100mg of the catalyst, and activate it by injecting feed gas at a temperature of 450°C and atmospheric pressure at 50mL/min. The catalyst performance test is carried out after 2h, and several temperature control points are set in the experiment: 200, 225, 250, 275, 300, 350, 400, 450. The temperature is tested from high to low, and each temperature is kept for 80 minutes. The reaction results are shown in the table. 1.

Table 1: Under the above catalyst evaluation conditions, the catalyst performance table in each example and comparative example

Example 2

This example is the preparation of NiO-CeO ₂ -Y ₂ O ₃ catalyst, the mass ratio is NiO:CeO ₂ :Y ₂ O ₃ =3:5:2

making process:

S1: Dissolve 1.168g Ni(NO ₃ ) ₂ ·6H ₂ O, 1.232g Ce(NO ₃ ) ₃ ·6H ₂ O and 0.678g Y(NO ₃ ) ₃ ·6H ₂ O in 75ml deionized water, and stir magnetically To dissolve it

S2: Add 50 mL of 0.5 mol/L ammonium carbonate solution to the solution obtained in step S1, with a dropping rate of 1-2 mL/s;

S3: After continuing to stir the mixture obtained in step S2 for 30 minutes, let it stand for 12 hours;

S4: Suction filtration and washing of the mixture obtained in step S3, and the washing water volume is 300 mL;

S5: Put the solid material obtained in step S4 into a vacuum oven for 12 hours, and set the temperature to 60°C;

S6: Grind the solid obtained in step S5 into powder, and calcinate in a muffle furnace at 400-500° C. for 3-5 hours to obtain the final product.

Testing process:

The performance test of the catalyst in this experiment was carried out in a micro fixed-bed reactor. The application process for the carbon dioxide methanation catalyst was as follows: Weigh 100mg of the catalyst, and activate it by injecting feed gas at a temperature of 450°C and atmospheric pressure at 50mL/min. The catalyst performance test is carried out after 2h, and several temperature control points are set in the experiment: 200, 225, 250, 275, 300, 350, 400, 450. The temperature is tested from high to low, and each temperature is kept for 80 minutes. The reaction results are shown in the table. 1.

Example 3

This example is the preparation of NiO-CeO ₂ -Y ₂ O ₃ catalyst, the mass ratio is NiO:CeO ₂ :Y ₂ O ₃ =3:4:3

making process:

S1: Dissolve 1.168g Ni(NO ₃ ) ₂ ·6H ₂ O, 0.986g Ce(NO ₃ ) ₃ ·6H ₂ O and 1.017g Y(NO ₃ ) ₃ ·6H ₂ O in 75ml deionized water, and stir magnetically To dissolve it

S2: Add 50 mL of 0.5 mol/L ammonium carbonate solution to the solution obtained in step S1, with a dropping rate of 1-2 mL/s;

S3: After continuing to stir the mixture obtained in step S2 for 30 minutes, let it stand for 12 hours;

S4: Suction filtration and washing of the mixture obtained in step S3, and the washing water volume is 300 mL;

S5: Put the solid material obtained in step S4 into a vacuum oven for 12 hours, and set the temperature to 60°C;

S6: Grind the solid obtained in step S5 into powder, and calcinate in a muffle furnace at 400-500° C. for 3-5 hours to obtain the final product.

Testing process:

The performance test of the catalyst in this experiment was carried out in a micro fixed-bed reactor. The application process for the carbon dioxide methanation catalyst was as follows: Weigh 100mg of the catalyst, and activate it by injecting feed gas at a temperature of 450°C and atmospheric pressure at 50mL/min. The catalyst performance test is carried out after 2h, and several temperature control points are set in the experiment: 200, 225, 250, 275, 300, 350, 400, 450. The temperature is tested from high to low, and each temperature is kept for 80 minutes. The reaction results are shown in the table. 1.

Refer to Figure 2 for the TEM image of the 0.3NiO-0.3Y ₂ O ₃ -CeO _{2 catalyst sample in this example.}

It can be seen from the TEM spectrum (Figure 2) that after the reaction, the elements are uniformly dispersed.

Comparative example 1

In this example, _{the preparation of NiO-CeO 2} catalyst, the mass ratio NiO:CeO ₂ =3:7

making process:

S1: Dissolve 1.168g Ni(NO ₃ ) ₂ ·6H ₂ O and 1.725g Ce(NO ₃ ) ₃ ·6H ₂ O in 75ml deionized water, and dissolve it with a magnetic stirrer;

S2: Add 50 mL of 0.5 mol/L ammonium carbonate solution to the solution obtained in step S1, with a dropping rate of 1-2 mL/s;

S3: After continuing to stir the mixture obtained in step S2 for 30 minutes, let it stand for 12 hours;

S4: Suction filtration and washing of the mixture obtained in step S3, and the washing water volume is 300 mL;

S5: Put the solid material obtained in step S4 into a vacuum oven for 12 hours, and set the temperature to 60°C;

S6: Grind the solid obtained in step S5 into powder, and calcinate in a muffle furnace at 400-500° C. for 3-5 hours to obtain the final product.

Testing process:

The performance test of the catalyst in this experiment was carried out in a micro fixed-bed reactor. The application process for the carbon dioxide methanation catalyst was as follows: Weigh 100mg of the catalyst, and activate it by injecting feed gas at a temperature of 450°C and atmospheric pressure at 50mL/min. The catalyst performance test is carried out after 2h, and several temperature control points are set in the experiment: 200, 225, 250, 275, 300, 350, 400, 450. The temperature is tested from high to low, and each temperature is kept for 80 minutes. The reaction results are shown in the table. 1.

Comparative example 2

In this example, _{the preparation of NiO-Y 2} O ₃ catalyst, the mass ratio NiO:Y ₂ O ₃ =3:7

making process:

S1: Dissolve 1.168g Ni(NO ₃ ) ₂ ·6H ₂ O and 2.373g Y(NO ₃ ) ₃ ·6H ₂ O in 75ml of deionized water, and dissolve it with a magnetic stirrer;

S2: Add 50 mL of 0.5 mol/L ammonium carbonate solution to the solution obtained in step S1, with a dropping rate of 1-2 mL/s;

S3: After continuing to stir the mixture obtained in step S2 for 30 minutes, let it stand for 12 hours;

S4: Suction filtration and washing of the mixture obtained in step S3, and the washing water volume is 300 mL;

S5: Put the solid material obtained in step S4 into a vacuum oven for 12 hours, and set the temperature to 60°C;

S6: Grind the solid obtained in step S5 into powder, and calcinate in a muffle furnace at 400-500° C. for 3-5 hours to obtain the final product.

Testing process:

The performance test of the catalyst in this experiment was carried out in a micro fixed-bed reactor. The application process for the carbon dioxide methanation catalyst was as follows: Weigh 100mg of the catalyst, and activate it by injecting feed gas at a temperature of 450°C and atmospheric pressure at 50mL/min. The catalyst performance test was carried out after 2h, and several temperature control points were set in the experiment: 200, 225, 250, 275, 300, 350, 400, 450. The temperature was tested from high to low, and each temperature was kept for 80 minutes. The reaction results are shown in the table. 1.

The results show that compared with the nickel-based catalysts with pure cerium oxide or pure yttrium oxide as the carrier _{, adding yttrium metal to Ni-CeO 2} can significantly increase the activity of the catalyst, not only greatly increase the conversion rate of carbon dioxide, but also increase methane. The selectivity also reduces the yield of by-product carbon monoxide and increases the yield of methane.

The foregoing description of the embodiments is to facilitate those of ordinary skill in the technical field to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative work. Therefore, the present invention is not limited to the above-mentioned embodiments. According to the disclosure of the present invention by those skilled in the art, all improvements and modifications made without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (10)

1. A supported nickel-based catalyst for carbon dioxide methanation reaction is characterized in that the supported nickel-based catalyst is a mixed oxide composed of the following components by weight:

   Nickel oxide 3;

   Metal oxide carrier 4～6;

   Doping with metal oxides 1-3.
2. The supported nickel-based catalyst for the methanation of carbon dioxide according to claim 1, wherein the metal oxide support is ceria.
3. The supported nickel-based catalyst for the methanation of carbon dioxide according to claim 1, wherein the doped metal oxide is yttrium trioxide.
4. A method for preparing the supported nickel-based catalyst according to claim 1, characterized in that it comprises the following steps:

   S1: Dissolve the metal salts of nickel, cerium and yttrium in water to obtain solution A;

   S2: Add the carbonate solution to solution A, mix well, and let stand for 10-12 hours to obtain mixture B;

   S3: Suction filtration, washing and drying of mixture B to obtain solid C;

   S4: Grind the solid C into a powder, and then calcinate it at 400-500°C for 3 to 5 hours to obtain a finished catalyst.
5. The method for preparing a supported nickel-based catalyst according to claim 4, wherein the concentration of the carbonate solution is 0.5 mol/L.
6. The method for preparing a supported nickel-based catalyst according to claim 4, wherein the carbonate solution is an ammonium carbonate solution.
7. The method for preparing a supported nickel-based catalyst according to claim 4, wherein the metal salts of nickel, cerium and yttrium are all corresponding metal nitrates.
8. An application of the supported nickel-based catalyst in claim 1, characterized in that the reaction gas is combined with the load under the conditions of a reaction temperature of 200-450°C, a reaction pressure of normal pressure, and a space velocity of 30000L/(kg·h). Type nickel-based catalyst contact reaction to generate methane.
9. The application of a supported nickel-based catalyst according to claim 8, wherein the reaction gas is a mixed gas composed of hydrogen, carbon dioxide and inert gas.
10. The application of a supported nickel-based catalyst according to claim 8, wherein the supported nickel-based catalyst is activated with a reaction gas for 2 to 3 hours before the reaction, and the activation temperature is 400 to 450 hours.

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