Catalyst for low-temperature, high-efficiency ammonia cracking reaction, method for producing the same, and method for producing hydrogen using the same

Abstract

The present invention relates to a ruthenium-based ammonia cracking catalyst, and more particularly to an ammonia cracking catalyst in which ruthenium, an active metal, and potassium, an auxiliary metal, are supported on a lanthanum-containing yttria-stabilized zirconia support, and to a method for producing the same. The ammonia cracking catalyst according to the present invention, even when using a low content of ruthenium metal, can achieve very high ammonia conversion rates and hydrogen production efficiencies even at low temperatures compared to catalysts with the same ruthenium metal content by adjusting the ruthenium / potassium ratio together with a lanthanum-containing yttria-stabilized zirconia-alumina support, minimizing the content of chlorine and nitrogen compounds which are impurities in the catalyst, and specifying the position of the active metal in the catalyst.

Claims

1. A catalyst used in the ammonia cracking reaction, An ammonia cracking catalyst characterized by using lanthanum-containing yttria-stabilized zirconia (La-YSZ) as a support, supporting a bimetallic composite metal of ruthenium as the active metal and potassium as the auxiliary metal, and having chlorine and nitrogen compounds present in the catalyst at a concentration of 10 ppm or less relative to the weight of the catalyst.

2. The ammonia cracking catalyst according to claim 1, characterized in that the support is formed into a specific shape by supporting lanthanum on yttria-stabilized zirconia.

3. The ammonia cracking catalyst according to claim 1, characterized in that lanthanum is supported in an amount of 1 to 5 wt% on an yttria-stabilized zirconia support.

4. The ammonia cracking catalyst according to claim 1, characterized in that the yttria content in the yttria-stabilized zirconia support is 5 to 14 wt% relative to the weight of the support.

5. The lanthanum-containing yttria-stabilized zirconia support has a volume density of 0.5 to 1.2 g / ml and a specific surface area of ​​20 to 100 m². ２ / g, stomatal volume of 0.1-0.2 cm ３ The ammonia cracking catalyst according to claim 1, characterized in that it has a concentration of 1 / g and an average pore size distribution in the range of 9 to 20 nm.

6. The ammonia cracking catalyst according to claim 1, characterized in that ruthenium is distributed within 30% of the length from the outer edge of the catalyst to the center, and potassium is uniformly distributed inside the catalyst.

7. Ruthenium is present in an amount of 0.5–3.0 wt% relative to the weight of the catalyst, and in a quantity of 0.005–0.028 wt% / m within 30% of the catalyst's outer edge in the length from the outer edge to the center of the catalyst. ２ The ammonia cracking catalyst according to claim 1, characterized in that it exists in a certain content.

8. The potassium is present in an amount of 4 to 10 wt% relative to the weight of the catalyst, and within the catalyst, it is present in an amount of 0.01 to 0.07 wt% / m³. ２ The ammonia cracking catalyst according to claim 1, characterized in that it is uniformly present in a certain content.

9. The ammonia cracking catalyst according to claim 1, characterized in that the weight ratio of potassium / ruthenium is in the range of 3 to 6.

10. The ammonia cracking catalyst according to claim 1, characterized in that the residual chlorine compounds in the catalyst are removed to 10 ppm or less by an ion exchange method using a basic substance.

11. The ammonia cracking catalyst according to claim 1, characterized in that the residual chlorine compounds in the catalyst are removed to 10 ppm or less by a high-temperature heat treatment method.

12. A method for producing a catalyst used in an ammonia cracking reaction, a) Zirconium precursor (ZrO ２ ) is dissolved in a solvent and then yttria (Y ２ O ３ The process involves coprecipitation of the following and firing at 800-1000°C to produce YSZ powder, b) A step of supporting, by an impregnation method, a solution in which a lanthanum precursor (La(NO ３ )) is dissolved in a solvent, on the produced YSZ powder support; ３ ​ c) The powder on which La is supported is dried at 100-120°C and then calcined at 500-600°C to remove residual NO ３ After removing the material, the molding step is performed. d) La-YSZ molded body containing a ruthenium precursor (RuO ３ The steps include: ) a solution in which the substance is dissolved in a solvent is supported by a pressurized spray method at room temperature, e) After loading, the process involves drying at 100-120°C, firing at 400-600°C, and removing residual Cl by ion exchange. f) A potassium precursor (KNO) is added to the manufactured Ru / La-YSZ molded body. ３ The steps include: ) a solution in which the substance is dissolved in a solvent is supported by a pressurized spray method at room temperature, g) After loading, dry at 100-120°C and then calcine at 500-600°C to remove residual NO ３ The steps to remove, h) A method for producing an ammonia cracking catalyst, characterized by comprising the step of rapidly reducing the manufactured Ru-K / La-YSZ oxidation catalyst at a high temperature using hydrogen gas in the range of 400 to 600°C to produce a final catalyst.

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