Hydrocarbons from sunflower oil over partly reduced catalysts

• Published in: Reaction kinetics, mechanisms and catalysis mechanisms and catalysis, 2012-06, Vol.106 (1), p.99-111
• Main Authors: Harnos, Szabolcs, Onyestyák, György, Kalló, Dénes
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Physical Chemistry
• ISSN: 1878-5190; 1878-5204
• DOI: 10.1007/s11144-012-0424-6

The present work focuses on the study of non-sulfided catalysts in the hydroconversion of sunflower oil to aliphatic paraffins, although sulfided and non-sulfided forms of one commercial catalyst are compared, too. Supported metal and metal oxide catalysts such as palladium on activated carbon or alumina, Ni/Al 2 O 3 with different Ni-loadings and NiMo/Al 2 O 3 samples were compared at 340 °C and 21 bar in a fixed-bed reactor. The reaction proceeded in consecutive steps of hydrogenolysis to carboxylic acids (CA) and propane, and hydrodeoxygenation (HDO) of the CA intermediates. Two HDO routes can be distinguished on the basis of obtained product distributions regarding the dominating alkane products (C 17 and/or C 18 ) characteristic of the different catalysts compared: (i) the hydrodecarbonylation/decarboxylation resulting chain-shortened alkanes (on supported Pd and Ni) or (ii) the reduction of full oxygen content to get alkanes and water preserving the original length of linear C-chains (on NiMo/Al 2 O 3 ). Some of the standard, commercial NiMo/alumina catalysts can be applied for triglyceride transformation to green diesel without modification in sulfided or partly reduced form depending on the requirements of the refinery. Simple Ni/alumina samples without the admission of any other modifying component proved to be too active in side reactions (methanation of CO x evolved and alkane hydrogenolysis).