催化作用
钒
催化裂化
镍
焦炭
化学工程
开裂
材料科学
碳纤维
催化剂载体
非阻塞I/O
工业催化剂
冶金
化学
复合材料
有机化学
复合数
工程类
作者
U.J. Etim,Pingping Wu,Peng Bai,Wei Xing,Rooh Ullah,Fazle Subhan,Zifeng Yan
出处
期刊:Energy & Fuels
[American Chemical Society]
日期:2016-11-25
卷期号:30 (12): 10371-10382
被引量:17
标识
DOI:10.1021/acs.energyfuels.6b02505
摘要
The deposition of appreciable amounts of metal poisons and carbon poses serious problems to the refiner during fluid catalytic cracking (FCC) unit operation. To check the effects of these contaminants on the catalyst, an in-depth understanding of their locations and existing states becomes necessary. In this work, the location and nature of vanadium, nickel, and coke species on the FCC catalyst were investigated. Detailed analyses of catalyst samples, including industrial equilibrium catalysts (E-cats), were accomplished using a variety of characterization techniques. It was found that nickel and vanadium concentrated mainly in meso- and micropores of the FCC catalyst, respectively. On the surface of E-cats, vanadium exists mainly in +4 and +5 oxidation states, while nickel is present as NiO, NiAl2O4, and surface nickel hydrosilicates and as NiO and NiAl2O4 in the bulk. The formation of a large amount of NiAl2O4 on the alumina support by nickel indicates its preferential location in the alumina component of the FCC catalyst. When co-existing, a synergic effect between vanadium and nickel is likely. On the other hand, coke distributed within the catalyst pore spaces, exhibiting different behaviors in different catalysts as a result of the effects of the metals and steam treatment. The coke deposits consist of a layer of graphitized carbon with both hydrocarbon and aromatic carbon species. Results obtained in this study provide insights into the nature of contaminants of FCC catalysts and could help in the rational design of catalysts to alleviate the metal poisons during catalytic cracking.
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