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CN-119897111-B - Supported nickel-based catalyst, preparation method and application thereof, and ammonia decomposition hydrogen production method

CN119897111BCN 119897111 BCN119897111 BCN 119897111BCN-119897111-B

Abstract

The invention relates to the field of ammonia decomposition catalyst preparation, and discloses a supported nickel-based catalyst, a preparation method and application thereof, and a method for preparing hydrogen by ammonia decomposition. The supported nickel-based catalyst comprises a barium titanate carrier and nickel element supported on the barium titanate carrier, wherein the nickel content is 2-15 wt% based on the total weight of the catalyst and calculated on the basis of nickel oxide, and the average particle size of the catalyst is 1-10 microns. The catalyst has higher activity, is applied to ammonia decomposition hydrogen production, and has higher ammonia decomposition conversion rate at low temperature and larger airspeed.

Inventors

  • GAO DI
  • SUN SHANGCONG
  • Jiang Qiuqiao
  • ZHAO DONGYUE

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260508
Application Date
20231027

Claims (18)

  1. 1. The supported nickel-based catalyst is characterized by comprising a barium titanate carrier and nickel element supported on the barium titanate carrier, wherein the content of nickel is 2-15% by weight based on the total weight of the catalyst and calculated on the basis of nickel oxide; wherein the average particle size of the catalyst is 1-10 microns; The preparation method of the supported nickel-based catalyst comprises the following steps: s1, grinding a titanium-containing compound and a barium-containing compound to obtain powder with an average particle size of 0.1-7 microns; s2, drying and first roasting the powder obtained in the step S1 to obtain a barium titanate carrier, wherein in the step S2, the first roasting condition comprises 600-800 ℃ for 2-6 hours; And S3, loading nickel element on the barium titanate carrier by adopting an impregnation method, and then performing second roasting and reduction.
  2. 2. The catalyst according to claim 1, wherein, The nickel content is 5-15 wt%, based on the total weight of the catalyst, calculated as nickel oxide.
  3. 3. The catalyst according to claim 1, wherein, The average particle size of the catalyst is 2-8 microns.
  4. 4. A method of preparing a supported nickel-based catalyst, the method comprising the steps of: s1, grinding a titanium-containing compound and a barium-containing compound to obtain powder with an average particle size of 0.1-7 microns; s2, drying and first roasting the powder obtained in the step S1 to obtain a barium titanate carrier, wherein in the step S2, the first roasting condition comprises 600-800 ℃ for 2-6 hours; s3, loading nickel element on a barium titanate carrier by adopting an impregnation method, and then performing second roasting and reduction; In the catalyst, the content of nickel is 2-15 wt% based on the total weight of the catalyst and calculated by nickel oxide; Wherein the average particle size of the catalyst is 1-10 microns.
  5. 5. The method of claim 4, wherein, In S1, the molar ratio of the barium-containing compound to the titanium-containing compound is 1:2-8.
  6. 6. The method of claim 5, wherein, In S1, the molar ratio of the barium-containing compound to the titanium-containing compound is 1:2-6.
  7. 7. The method of claim 4, wherein, The titanium-containing compound is titanium dioxide and/or metatitanic acid; The barium-containing compound is barium carbonate and/or barium hydroxide.
  8. 8. The method of claim 4, wherein, S1, the average grain diameter of the obtained powder is 1-6 microns; the grinding conditions in the step S1 comprise the rotating speed of 150-600rpm and the grinding time of 3-60min.
  9. 9. The method of claim 4, wherein, In S2, the drying condition comprises that the temperature is 70-120 ℃ and the time is 8-48 hours.
  10. 10. The method according to any one of claims 4-9, wherein, The impregnation method of S3 comprises the following steps: (1) Adding the aqueous solution containing nickel salt to a barium titanate carrier to obtain a catalyst precursor; (2) The catalyst precursor is aged, then dried and second calcined.
  11. 11. The method of claim 10, wherein, The nickel salt is used in an amount such that the catalyst is prepared with a nickel content of 2 to 15 wt% based on the total weight of the catalyst, calculated as nickel oxide.
  12. 12. The method of claim 11, wherein, The nickel salt is used in an amount such that the catalyst is prepared with a nickel content of 5 to 15 wt% based on the total weight of the catalyst, calculated as nickel oxide.
  13. 13. The method of claim 10, wherein, The aging conditions in the step (2) comprise the temperature of 40-60 ℃ and the time of 1-3 hours; the conditions of the second roasting in the step (2) comprise the temperature of 550-780 ℃ and the time of 2-5 hours.
  14. 14. The method of claim 10, wherein, The reduction conditions comprise 600-800 ℃ and 1-3 hours; the reduction is carried out in a reducing gas comprising hydrogen and optionally nitrogen and optionally an inert gas, the hydrogen being present in the reducing gas in a volume content of 10-100%.
  15. 15. The method of claim 14, wherein, The inert gas is selected from at least one of helium, argon and neon.
  16. 16. Use of a catalyst according to any one of claims 1 to 3 or a catalyst prepared by a process according to any one of claims 4 to 15 in the production of hydrogen by ammonia decomposition.
  17. 17. A process for producing hydrogen by ammonia decomposition, comprising contacting ammonia with a catalyst under ammonia decomposition conditions; Wherein the catalyst is the catalyst of any one of claims 1 to 3 or the catalyst prepared by the preparation method of any one of claims 4 to 15.
  18. 18. The method of claim 17, wherein, The ammonia decomposition conditions comprise a temperature of 550-650 ℃ and a volume space velocity of 5000-20000 mL/(g.h).

Description

Supported nickel-based catalyst, preparation method and application thereof, and ammonia decomposition hydrogen production method Technical Field The invention relates to the field of ammonia decomposition catalyst preparation, in particular to a supported nickel-based catalyst, a preparation method and application thereof, and a method for preparing hydrogen by ammonia decomposition. Background Hydrogen is currently almost derived from the catalytic steam reforming of fossil fuels, which is also the most established hydrogen production technology currently commercialized. However, the hydrogen gas obtained by catalytic reforming is accompanied by impurity gases such as carbon monoxide and carbon dioxide, and cannot be directly used as fuel for fuel cells. Therefore, the hydrogen-rich carrier ammonia is used as a raw material to produce the hydrogen without carbon emission, and the hydrogen production technology is efficient, clean and safe. In order to realize safe and green hydrogen production, it is important to develop a catalyst capable of efficiently catalyzing ammonia decomposition. The existing ammonia decomposition catalysts are divided into noble metal catalysts with ruthenium and platinum as active components and non-noble metal catalysts with iron and nickel as active components. Precious metals limit their use in large-scale industrialization due to high cost and low reserves. Therefore, the core of developing the high-efficiency low-cost ammonia decomposition hydrogen production technology is a non-noble metal catalyst with low cost, high activity and high stability. However, the non-noble metal catalyst needs more severe reaction conditions, the use temperature is generally higher than 800 ℃, and for this reason, extensive researches are conducted on a low-temperature non-noble metal ammonia decomposition catalyst, for example, CN1506299A discloses a nickel-based ammonia decomposition hydrogen-nitrogen mixed gas catalyst, the main active component of which is Ni, the carrier of which is SiO 2 or Al 2O3, and the auxiliary agent of which is one or more of IA, IIA, IIIB, VIII or rare earth elements, wherein the weight percentage of the nickel is 1-40%, and the weight percentage of the auxiliary agent component is 0.1-20%. SiO 2 or Al 2O3 is used as a carrier to prepare the catalyst, and although the performance of the catalyst is improved by introducing the auxiliary agent, ammonia decomposition can be carried out at 650 ℃, compared with the industrial catalyst, the reaction temperature at 800 ℃ is obviously reduced, but large particles are easily formed due to poor dispersion degree of the auxiliary agent on the surface of the carrier, so that the ammonia decomposition activity at low temperature is poor. CN115646500a discloses a catalyst for producing hydrogen by decomposing ammonia, the catalyst comprises an active metal component, an alkaline earth metal component, a lanthanide metal component and an auxiliary agent, the patent application adopts doped alkaline earth metal to improve the dispersity of a nickel-based catalyst, reduce the particle size, and has a certain improvement on the activity of the catalyst compared with an unmodified catalyst, although the reaction temperature is reduced to 550 ℃, the reaction space velocity is only 6000 mL/(g.h), and the improvement still remains. Disclosure of Invention The invention aims to solve the problem that the activity and stability of the existing ammonia decomposition catalyst at low temperature are to be further improved, and provides a supported nickel-based catalyst, a preparation method and application thereof and a method for preparing hydrogen by ammonia decomposition. The catalyst has higher activity, is applied to ammonia decomposition hydrogen production, and has higher ammonia decomposition conversion rate at low temperature and larger airspeed. In order to achieve the above object, according to one aspect of the present invention, there is provided a supported nickel-based catalyst comprising a barium titanate support and nickel element supported on the barium titanate support, wherein the content of nickel is 2 to 15wt% in terms of nickel oxide based on the total weight of the catalyst; Wherein the average particle size of the catalyst is 1-10 microns. The second aspect of the present invention provides a method for preparing a supported nickel-based catalyst, the method comprising the steps of: s1, grinding a titanium-containing compound and a barium-containing compound to obtain powder with an average particle size of 0.1-7 microns; S2, drying and first roasting the powder obtained in the step S1 to obtain a barium titanate carrier; s3, loading nickel element on the barium titanate carrier by adopting an impregnation method. The third aspect of the invention provides an application of the supported nickel-based catalyst in the first aspect or the supported nickel-based catalyst prepared by the preparation method in the second