Tuesday, November 20, 2012

Effect of Tetralin, Decalin and Naphthalene as Hydrogen Donors in the Upgrading of Heavy Oils

Procedia Engineering, Volume 42, 2012, Pages 585–594
Effect of Tetralin, Decalin and Naphthalene as Hydrogen Donors in the Upgrading of Heavy Oils
L.O. Alemán-Vázquez a, J.L.Cano-Domínguez b, J.L. García-Gutiérrez b
a Mexican Petroleum Institute. Transformation Processes Program, Pachuca-Cd. Sahagún Road km.7.5, Canacintra Industrial Park, Mineral de la Reforma, Hgo., C.P. 42186, Mexico
b Mexican Petroleum Institute. Transformation Processes Program, Eje Central Lázaro Cárdenas Norte 152, San Bartolo Atepehuacan, Mexico, D. F., C.P. 07730, Mexico
Abstract
Heavy crude oils typically are upgraded by thermal cracking or hydrocracking.  These methods are based on carbon rejection and hydrogen addition routes.  The processes have a number of unresolved problems yet to be solved.  They include coke deposition both on the reactor walls and on the catalyst, low quality of products and low efficiency of usage of hydrogen.  An efficient technology for the production of high quality distillates from heavy oils or residua has yet to be developed.
The use of hydrogen donors is an interesting alternative for improving the yield of valuable liquid products in the hydroprocessing of heavy feeds.  The donors usually consist of polycyclic naphthenic-aromatic or naphthenic compounds that can be reversibly hydrogenated-dehydrogenated in the reacting mixture.  The molecules of the hydrogen donors are dehydrogenated, transferring hydrogen atoms to the heavy hydrocarbons in the oil.  This improves the quality of the cracked products and minimizes the polymerization of the heavier molecules via a free radicals mechanism.  Authors focus on the effect of tetralin, decalin and naphthalene as hydrogen donors (Hdonors) in the thermal cracking of a Mexican heavy crude oil (12.1 °API) in the presence of hydrogen or methane as reducing agents.
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