阅读说明：本技术 一种中空结构钨酸镍基甲烷化催化剂 (Nickel tungstate-based methanation catalyst with hollow structure ) 是由 刘庆 杨洪远 于 2019-10-12 设计创作，主要内容包括：本发明涉及能源催化领域,具体地,本发明涉及一种中空结构钨酸镍基甲烷化催化剂。所述催化剂以不同植物花粉为硬模板剂,采用连续吸附反应法制备NiWO<Sub>4</Sub>催化剂。本发明得到的甲烷化催化剂具有中空形貌、高比表面积、高机械强度、高活性、热稳定性好、抗积碳、抗烧结性能强和成本低廉的优点。(The invention relates to the field of energy catalysis, in particular to a nickel tungstate-based methanation catalyst with a hollow structure. The catalyst takes different plant pollen as a hard template agent and adopts a continuous adsorption reaction method to prepare NiWO 4 A catalyst. The methanation catalyst obtained by the invention has the advantages of hollow appearance, high specific surface area, high mechanical strength, high activity, good thermal stability, carbon deposition resistance, strong sintering resistance and low cost.)

1. A nickel tungstate-based methanation catalyst with a hollow structure is characterized in that an active component precursor of the catalyst is NiWO₄。

2. The hollow structure nickel tungstate based methanation catalyst as claimed in claim 1, wherein the catalyst active component is Ni.

3. A nickel tungstate-based methanation catalyst with a hollow structure is characterized by being prepared by the following method:

(1) pretreatment of plant pollen with hard template agent

(1-1) using <58 μm size plant pollen as a hard template;

(1-2) ultrasonically washing the plant pollen obtained in the step (1-1) with an ethanol solution for 4 ~ 7 times, each time for 20 ~ 50 min;

(1-3) filtering the suspension obtained in the step (1-2) at 40 ~ 70^oDrying for 24 h at C to obtain required pollen as hard template agent;

(2) NiWO prepared by hard template continuous adsorption reaction method₄Catalyst and process for preparing same

(2-1) dispersing plant pollen with a certain mass in 100mL of ethanol solution to form suspension;

(2-2) preparing 100mL of soluble nickel salt aqueous solution with a certain concentration, and marking as A solution;

adding the solution A into the suspension of the step (2-1), and mixing the mixture at 40^oSoaking for 12 hr, centrifuging, washing with water and ethanol, and soaking at 40 ~ 70^oDrying for 8 ~ 12 h under C;

(2-3) dispersing the plant pollen obtained in the step (2-2) in 100mL of ethanol solution again to form a suspension;

(2-4) preparing 100mL of sodium tungstate aqueous solution with a certain concentration, and recording as a solution B;

adding the solution B into the suspension obtained in the step (2-3), and mixing the mixture at 40^oSoaking for 12 hr, centrifuging, washing with water and ethanol, and soaking at 40 ~ 70^oDrying for 8 ~ 12 h under C;

(2-5) recording the plant pollen obtained in the step (2-4) as a circulation unit, and then repeating the operation of the step (2-1) ~ (2-4) on the plant pollen for 3 ~ 7 cycles;

(2-6) placing the plant pollen finally obtained in the step (2-5) in a muffle furnace at 500 ~ 650^oCalcining for 2 ~ 5 h to obtain the target NiWO₄A catalyst.

4. The hollow structure nickel tungstate-based methanation catalyst as claimed in claim 3, wherein the plant pollen in the steps (1) and (2) is lotus pollen, rape pollen, sweet potato pollen or sunflower pollen.

5. The hollow structure nickel tungstate-based methanation catalyst as claimed in claim 3, wherein the soluble nickel salt in step (2-2) is nickel acetate, nickel sulfate, nickel nitrate or nickel chloride.

Technical Field

The invention relates to the field of energy catalysis, in particular to a nickel tungstate-based methanation catalyst with a hollow structure.

Background

Natural gas is considered the cleanest fossil fuel that can meet industry stringent air emission standards. However, in view of the energy resource characteristics of rich coal, poor oil and less gas in China, coal is still the main body of energy consumption in China, but about 80% of coal consumption is directly converted through combustion, the heat energy utilization rate is low, and a large amount of pollutants are discharged. Therefore, the development of a high-efficiency, low-carbon and clean coal resource utilization technology has very important significance. The gas obtained by pyrolyzing and gasifying coal or biomass mainly contains H₂And CO, the main components of the coke oven gas in the coking industry areIs also H₂And CO, wherein the mixed gas containing CO can be subjected to conversion, purification and other processes and then can be subjected to methanation reaction to generate CH₄. The method can promote the efficient and clean comprehensive utilization of coal, improve the heat density of fuel gas and provide a feasible way for filling the gap of natural gas requirements in China. The methanation process mainly involves the following reactions:

CO + 3H₂→ CH₄+ H₂O Δ_r H _m= –206 kJ/mol

the reaction is a strong exothermic reaction, and excessive reaction heat easily causes local overheating and temperature runaway phenomena, so that sintering and carbon deposition of active components are caused. Obviously, the carbon deposition resistance and high temperature resistance of the catalyst will directly affect the life of the catalyst. Therefore, the development of a methanation catalyst which is highly active and capable of operating stably at high temperatures for a long time is one of the key factors of the synthesis gas methanation process.

Carried on Al₂O₃、SiO₂、TiO₂、ZrO₂Ni-based metal catalysts on oxides such as MgO are widely used as CO methanation catalysts. The catalysts can basically achieve ideal effects in applications of ammonia synthesis and low-concentration CO removal in the fuel cell industry, but the carbon deposition and sintering phenomena are serious due to the fact that the CO concentration in the methanation reaction of the synthesis gas obtained by coal or biomass gasification is high, and the heat release of the methanation reaction is strong. Therefore, the development of a novel catalyst suitable for high-concentration CO methanation is of great significance.

Nickel tungstate (NiWO)₄) Is one of the important inorganic materials in the metal tungstate family, and is widely applied due to the high activity of the inorganic materials on the hydrodesulfurization of crude oil fractions, the preparation of propylene by the hydrogenation of propylene oxide and humidity sensors. In addition, NiWO₄Have been explored in other potential applications, such as photoanodes. However, NiWO₄The application of the material in the methanation reaction of CO is rarely reported, so the material has a very wide application prospect.

Disclosure of Invention

The invention uses plant pollen as a hard template agent and adopts coptis rootNiWO with hollow appearance, high specific surface area, high activity, sintering resistance and carbon deposition resistance prepared by continuous adsorption reaction method₄A CO-based methanation catalyst. The invention not only improves the activity and stability of the catalyst, but also widens the application of the tungstate material in the field of catalysis.

Based on the above, one of the purposes of the invention is to provide a nickel tungstate-based methanation catalyst with a hollow structure.

In order to achieve the purpose, the invention adopts the following technical scheme:

a nickel tungstate-based methanation catalyst with a hollow structure, wherein active components of the catalyst exist in NiWO₄Wherein the active component is Ni.

The invention relates to a nickel tungstate-based methanation catalyst with a hollow structure, which is NiWO prepared by using plant pollen as a hard template agent and adopting a continuous adsorption reaction method₄Has excellent mechanical strength and thermal stability; the NiWO formed by adopting plant pollen as a hard template agent₄The catalyst has a certain micro-nano structure, so that the specific surface area of the catalyst is increased, and the catalytic performance of the catalyst is further improved.

The second object of the present invention is to provide a process for producing the above catalyst.

The invention relates to a nickel tungstate-based methanation catalyst with a hollow structure, which is prepared by the following steps:

(1) pretreatment of plant pollen with hard template agent

(1-1) crushing plant pollen by using a universal crusher, and screening parts with the size of less than 58 mu m;

(1-2) washing the plant pollen obtained in the step (1-1) with an ethanol solution for 4 ~ 7 times under ultrasonic radiation, each time for 20 ~ 50 min;

(1-3) filtering the suspension obtained in the step (1-2) to obtain plant pollen at 40 ~ 70^oAnd drying for 24 hours at the temperature of C to obtain the required pollen serving as the hard template agent.

(2) NiWO prepared by hard template continuous adsorption reaction method₄Catalyst and process for preparing same

(2-1) dispersing plant pollen with a certain mass in 100mL of ethanol solution to form suspension;

(2-2) preparing 100mL of soluble nickel salt aqueous solution with a certain concentration, and marking as A solution. Adding the solution A into the suspension of the step (2-1), and mixing the mixture at 40^oSoaking for 12 hr, centrifuging, washing with water and ethanol, and soaking at 40 ~ 70^oDrying for 8 ~ 12 h under C;

(2-3) dispersing the plant pollen obtained in the step (2-2) in 100mL of ethanol solution again to form a suspension;

and (2-4) preparing 100mL of sodium tungstate aqueous solution with a certain concentration, and recording as a solution B. Adding the solution B into the suspension obtained in the step (2-3), and mixing the mixture at 40^oSoaking for 12 hr, centrifuging, washing with water and ethanol, and soaking at 40 ~ 70^oDrying for 8 ~ 12 h under C;

(2-5) recording the plant pollen obtained in the step (2-4) as a circulation unit, and then repeating the operation of the step (2-1) ~ (2-4) on the plant pollen for 3 ~ 7 cycles;

(2-6) placing the plant pollen finally obtained in the step (2-5) in a muffle furnace 500 ~ 650^oCalcining for 2 ~ 5 h to obtain NiWO₄A catalyst.

Preferably, the plant pollen selected in the step (1-1) is any one of lotus pollen, rape pollen, sweet potato pollen or sunflower pollen.

Preferably, the mass of the plant pollen in the step (2-1) is 1 ~ 4 g.

Preferably, the ethanol solution in the steps (2-1) and (2-3) is EtOH/H₂O =1:1, volume ratio.

Preferably, the soluble nickel salt used in step (2-2) is any one of nickel acetate, nickel sulfate, nickel nitrate and nickel chloride.

Preferably, the concentration of the soluble nickel salt in the step (2-2) is 0.0005 ~ 0.001.001 mol/L.

Preferably, the concentration of sodium tungstate in the step (2-4) is 0.0005 ~ 0.001.001 mol/L.

Compared with the prior art, the invention has the following beneficial effects:

the invention takes different plant pollen as hard template agent and adopts a continuous adsorption reaction method to prepare NiWO₄The catalyst has the characteristics of hollow appearance, high specific surface area, high mechanical strength, high catalytic activity, good thermal stability, carbon deposition resistance, strong sintering resistance and the like, and shows excellent catalytic performance in the methanation reaction of CO.

Drawings

Figure 1 is an XRD spectrum of the sample of example 1.

FIG. 2 is a 240000-fold SEM image of the magnification of a sample of example 1.

Detailed Description

The following examples further illustrate the technical solution of the present invention, but the present invention is not limited to the following examples.