Cobalt supported on CNTs-covered γ- and nano-structured alumina catalysts utilized for wax selective Fischer-Tropsch synthesis

• Published in: Journal of natural gas chemistry Vol. 21; no. 6; pp. 713 - 721
• Main Authors: Hemmati, Mohammad Reza, Kazemeini, Mohammad, Khorasheh, Farhad, Zarkesh, Jamshid, Rashidi, Alimorad
• Format: Journal Article
• Language: English
• Published: Chengdu Elsevier B.V 01.11.2012; Dalian Institute of Chemical Physics
• Subjects: Aluminum oxide; carbon nanotubes; Catalysis; catalyst deactivation; Catalysts; Catalysts: preparations and properties; Chemistry; Cobalt; Exact sciences and technology; Fischer-Tropsch synthesis; gamma alumina; General and physical chemistry; Materials selection; nano-structured alumina; Nanomaterials; Nanostructure; Selectivity; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; 合成蜡; 氧化铝催化剂; 氧化铝载体; 碳纳米管; 纳米结构; 覆盖; 钴基催化剂; 钴溶液; Fischer-Tropsch synthesis; gamma alumina; carbon nanotubes; catalyst deactivation; nano-structured alumina; Performance evaluation; Deactivation; Fischer Tropsch synthesis; Carbon nanotubes; Nanostructure; Paraffin; Cobalt; Supported catalyst; Wax; Sol gel process; Catalyst activity; Alumina
• ISSN: 1003-9953
• DOI: 10.1016/S1003-9953(11)60424-6

Cobalt supported on carbon nanotubes （CNTs）-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis （FTS）. Problems associated with shaping of Co/CNTs into extrudates or pellets as well as catalyst attrition rendered these materials unfavorable for industrial applications. In this investigation regular γ- and nano-structured （N-S） alumina as well as CNTs-covered regular γ- and N-S-alumina supports were impregnated by cobalt nitrate solution to make new cobalt-based catalysts which were also promoted by Ru. The catalysts were characterized and tested in a micro reactor to evaluate their applicability in FTS. γ-Al2O3 was prepared by calcination of bohemite and N-S-Al2O3 was prepared by sol-gel method using aluminum chloride as starting material. Catalyst evaluations indicated that N-S-Al2O3 was superior to regular γ-Al2O3 and that CNTs-covered alumina supports were favored over non-covered ones in terms of activity and heavy hydrocarbon selectivity. These were justified by porosimetric characteristics of the catalysts and existence of CNTs points of view. CNTs-covered catalysts also showed higher wax selectivity and better resistance to deactivation. Furthermore, TPR analysis indicated that the cobalt aluminate phase, which is responsible for the permanent deactivation of alumina supported Co-based catalysts, did not form on alumina supported Co-based catalysts covered with CNTs due to weaker interactions between cobalt and alumina.