阅读说明：本技术 一种Ni基催化剂的制备方法 (Preparation method of Ni-based catalyst ) 是由 何素芳 杨欢 刘能生 罗永明 何素云 张磊 王云珠 泮子恒 赵燚 陆继长 何德东 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种Ni基催化剂的制备方法,该方法以柠檬酸、硝酸铈或硝酸镧、硝酸钙、硝酸镍为原料,经过水浴加热形成湿凝胶后,采用微波煅烧法直接加热湿凝胶快速合成Ni基催化剂Ni/CaO-CeO<Sub>2</Sub>或Ni/CaO-La<Sub>2</Sub>O<Sub>3</Sub>；本发明制备的催化剂在中低温下对乙醇重整制氢的催化活性和稳定性均较好,450℃就能使乙醇转化率达到100%,20Ni/CaO-10CeO<Sub>2</Sub>催化剂在550℃连续反应200h乙醇转化率还能保持100%；与传统马弗炉煅烧法制备的催化剂相比,本发明方法制备的催化剂对氢气的选择性更好,并且本发明方法中催化剂的合成时间短和能耗低,从而大大降低生产成本,这也为醇类重整制氢催化剂的工业化进程开辟了一条新的途径。(The invention discloses a preparation method of a Ni-based catalyst, which takes citric acid, cerium nitrate or lanthanum nitrate, calcium nitrate and nickel nitrate as raw materials, forms wet gel by water bath heating, and directly heats the wet gel by a microwave calcination method to quickly synthesize the Ni-based catalyst Ni/CaO-CeO 2 Or Ni/CaO-La 2 O 3 (ii) a The catalyst prepared by the invention has good catalytic activity and stability for reforming ethanol to prepare hydrogen at medium and low temperature, the ethanol conversion rate can reach 100% at 450 ℃, and 20Ni/CaO-10CeO 2 The catalyst can continuously react for 200h at 550 ℃ and the ethanol conversion rate can also be kept at 100 percent; compared with the catalyst prepared by the traditional muffle furnace calcination method, the catalyst prepared by the method has better selectivity to hydrogen, and the catalyst in the method has short synthesis time and low energy consumption, so that the production cost is greatly reduced, and a new way is opened up for the industrial process of the alcohol reforming hydrogen production catalyst.)

1. A method for preparing a Ni-based catalyst, comprising the steps of:

(1) adding cerium nitrate or lanthanum nitrate, calcium nitrate and nickel nitrate into deionized water, stirring until the cerium nitrate or the lanthanum nitrate, the calcium nitrate and the nickel nitrate are completely dissolved, then adding citric acid into the mixed solution, and stirring until the citric acid is completely dissolved;

(2) heating the solution obtained in the step (1) in a water bath at 75-85 ℃ for 4-5h to obtain wet gel;

(3) calcining the wet gel obtained in the step (2) in a microwave muffle furnace at the temperature of 850 ℃ under the microwave condition of 800-₂Or Ni/CaO-La₂O₃Wherein the content of Ni is 8-20%, CeO₂Or La₂O₃The content is 5-15%, and the content of CaO is 87-65%.

2. The method for producing a Ni-based catalyst according to claim 1, characterized in that: the mass ratio of the nickel nitrate to the citric acid is 1: 3.4-9.5.

3. The method for producing a Ni-based catalyst according to claim 1, characterized in that: in the step (3), the temperature rising rate is 10 ℃/min, and the temperature reducing rate is 10 ℃/min.

4. Use of the Ni-based catalyst produced by the Ni-based catalyst production method according to any one of claims 1 to 3 in hydrogen production, characterized in that: ethanol and water are used as raw materials, a Ni-based catalyst is used as a catalyst, an ethanol aqueous solution is gasified and then is introduced into a fixed bed reactor filled with the catalyst, and hydrogen is prepared at the temperature of 450-700 ℃ and under the pressure of 0.3 MPa.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a preparation method of a Ni-based catalyst and application of the Ni-based catalyst in hydrogen production by ethanol steam reforming.

Background

Ethanol is a renewable energy source with low toxicity, already industrialized production and easy storage, and hydrogen production by steam reforming has become a hotspot in hydrogen energy development. The nickel-based catalyst is widely applied to the research of the hydrogen production reaction by reforming ethanol steam due to low price and superior catalytic performance. However, the nickel-based catalyst has poor stability and is easy to be deactivated by sintering and carbon deposition. The prior methods mostly select a proper carrier or add an auxiliary agent on the basis of the carrier to improve the stability of the nickel-based catalyst. The carriers commonly used at present comprise alkaline materials (ZnO, CaO, MgO and the like) and amphoteric materials (A1)₂0₃、Ti0₂、Ce0₂Etc.), acidic materials (diatomaceous earth, zeolite, etc.), neutral materials (asbestos, activated carbon, etc.), but the single-component carrier always has the defects of low stability, poor selectivity or low carbon deposition resistance (such as Ni-A1)₂0₃ Catalyst A1 ₂0₃Catalysts with more acidic sites are prone to carbon deposition and deactivation). Addition of promoters (e.g., Ce 0) to single-component nickel-based catalysts₂、La₂O₃Etc.) can well regulate the acidity and alkalinity of the carrier so as to achieve the aim of improving the stability and the activity of the catalyst, but in general, a nickel-based catalyst which has relatively good stability and activity and is suitable for industrial large-scale production is not found.

Addition of promoters (e.g. Ce 0) to the catalyst₂、La₂O₃Etc.) are known, and impregnation, coprecipitation or coprecipitation followed by impregnation are conventional methodsBasically, the method has the problems of complicated or difficult control of preparation process, harsh preparation conditions and the like, and has high cost, which restricts the application of the current catalyst in the hydrogen production of industrial alcohols to a certain extent.

Disclosure of Invention

Aiming at the defects of complex synthesis process and high synthesis cost in the prior art, the invention provides the preparation method of the Ni-based catalyst with simple preparation method, low cost and excellent performance.

The method comprises the following steps:

(1) adding cerium nitrate or lanthanum nitrate, calcium nitrate and nickel nitrate into deionized water, stirring until the cerium nitrate or the lanthanum nitrate, the calcium nitrate and the nickel nitrate are completely dissolved, then adding citric acid into the mixed solution, and stirring until the citric acid is completely dissolved;

the mass ratio of the nickel nitrate to the citric acid is 1: 3.4-9.5;

(2) heating the solution obtained in the step (1) in a water bath at 75-85 ℃ for 4-5h to obtain wet gel;

(3) calcining the wet gel obtained in the step (2) in a microwave muffle furnace at the temperature of 850 ℃ under the microwave condition of 800-₂Or Ni/CaO-La₂O₃Wherein the content of Ni is 8-20%, CeO₂Or La₂O₃The content is 5-15%, and the content of CaO is 87-65%;

the heating rate is 10 ℃/min, and the cooling rate is 10 ℃/min.

The invention also aims to apply the Ni-based catalyst prepared by the method in the preparation of hydrogen, namely ethanol and water vapor are taken as raw materials, the Ni-based catalyst is taken as the catalyst, an ethanol aqueous solution is gasified and then is introduced into a fixed bed reactor filled with the catalyst, and the hydrogen is prepared at the temperature of 450-700 ℃ and under the pressure of 0.3 MPa.

Compared with the prior art, the invention has the outstanding effects that:

1. the microwave is adopted to directly heat and calcine the wet gel, the heating is more uniform than that of a solid catalyst, and the performance of the synthesized Ni-based catalyst is better, thereby providing reference value for the preferential selection of the currently prepared catalyst;

2. the catalyst prepared by the method has good catalytic performance and stability, simple preparation process and low energy consumption, and saves nearly 80% of preparation time;

3. the catalyst prepared by the invention is also suitable for other hydrogen production reactions, and the multi-field application of the catalyst is really realized.

Drawings

FIG. 1 shows microwave-prepared 20Ni/CaO-10CeO₂catalyst-W and 20Ni/CaO-10CeO prepared by traditional calcination method₂-C catalyst ethanol conversion vs. graph;

FIG. 2 shows microwave-prepared 20Ni/CaO-10CeO₂catalyst-W and 20Ni/CaO-10CeO prepared by traditional calcination method₂-C catalyst hydrogen selectivity contrast plot;

FIG. 3 shows microwave-prepared 20Ni/CaO-10CeO₂Stability diagram of W catalyst at reaction temperature 550 ℃.

Detailed Description

The present invention is further illustrated by the following examples, but the scope of the invention is not limited to the above-described examples.