石油炼制与化工 ›› 2020, Vol. 51 ›› Issue (2): 25-30.

• 催化剂 • 上一篇    下一篇

金属元素改性的超高温氨分解催化剂Ni/Mg-Al的结构及性能

常秋连1,2,3,李培霖1,2,3,陈松清4,赵鹏1,2,3,颜丙峰1,2,3   

  1. 1.煤炭科学技术研究院有限公司煤化工分院
    2.国家能源煤炭高效利用与节能减排技术装备重点实验室
    3.煤基节能环保炭材料北京市重点实验室
    4.马鞍山钢铁股份有限公司煤焦化公司

  • 收稿日期:2019-08-05 修回日期:2019-10-22 出版日期:2020-02-12 发布日期:2020-02-27
  • 通讯作者: 常秋连 E-mail:cqlky2004@sina.com
  • 基金资助:
     

STRUCTURE AND PROPERTIES OF Ni/Mg-Al CATALYST MODIFIED BY DIFFERENT METAL ELEMENTS

    

  1.  
  • Received:2019-08-05 Revised:2019-10-22 Online:2020-02-12 Published:2020-02-27
  • Supported by:
     

摘要: 以MgO、Al2O3和ZrO粉末为载体,金属Ni为活性组分,金属元素Co、La等为助剂,制备超高温氨分解催化剂;采用X射线衍射(XRD)、BET比表面积测试(BET)、H2程序升温还原(H2-TPR)、透射电子显微镜(TEM)对其结构进行表征,并在催化剂评价装置上对其氨分解活性进行评价,考察不同金属元素对催化剂结构和性能的影响。XRD结果表明:制备的几种催化剂中均存在NiAl2O4尖晶石相;金属元素可以促使生成的NiAl2O4尖晶石的晶型更加完整;La对晶型的贡献大于Co和Zr。H2-TPR结果表明:加入金属元素La后,催化剂中形成了更多的晶相NiAl2O4,而加入金属元素Co后,生成了与载体具有强相互作用的类尖晶石结构的固溶体。BET及TEM结果表明:金属元素La有助于提高Ni物种在催化剂表面的分散度和浓度,形成更小的表面Ni粒子,从而提高Ni的活性位分布。在反应温度1 200 ℃、体积空速1 228 h-1的条件下,相比于Ni/Mg-Al和CoNi/ZrMg-Al催化剂,LaNi/ZrMg-Al催化剂表现出更好的高温耐磨损性能、抗烧结性能和热稳定性能。

关键词: 金属元素, 超高温, 氨分解率, Ni/Mg-Al催化剂

Abstract: Using MgO, Al2O3 and ZrO powder as carriers, nickel as active component and cobalt and lanthanum as auxiliary agents, ultra-high temperature ammonia decomposition catalysts were prepared. The structure of which was characterized by XRD, BET, TPR and TEM.To investigate the influence of different metal elements on the structure and performance of catalyst, catalyst evaluation device was used. XRD results show that NiAl2O4 spinel phase exists in all the catalysts; metal elements can promote the crystalline form of NiAl2O4 spinel; compared with Co and Zr, La contributes more to the crystalline form. TPR results show that more crystalline phase of NiAl2O4could be formedafter adding of La, and a stronger interaction with carrier is formed after adding Co. BET and TEM experiment show that La is helpful to improve the dispersion and concentration of Ni species on the catalyst surface, and to form smaller surface nickel particles, so as to improve the active site distribution of nickel. Compared with Ni/Mg-Al and CoNi/ZrMg-Al catalysts, LaNi/ZrMg-Al catalyst shows better high temperature wear resistance, sintering resistance and thermal stability under experimental condition of reaction temperature 1200 ℃, volume space velocity 1228 h-1.

Key words: metallic element, extraordinarily high temperature, ammonia decomposition, Ni/Mg-Al catalyst

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