abstracts - Институт катализа им. Г.К. Борескова

OP-I-35METHODS TO STUDY THE KINETICS OF ELEMENTARY STEPS OFFISCHER-TROPSCH SYNTHESIS ON COBALT CATALYSTSKhodakov A.Y. 1 , Fongarland P. 1 , Anfray J. 1,2 , Bremaud M. 1 , Jallais S. 3 , Peregryn B. 1 ,Lermontov A.S. 1 , Pietrzyk S. 1 and Schweich D. 21 Laboratoire de Catalyse de Lille, USTL, Bâtiment C3, 59655 Villeneuve d'Ascq, France2 Laboratoire de Génie des Procédés Catalytiques, 43 Bd du 11 novembre 1918, BP 2077,69616 Villeurbanne Cedex, France3 Air Liquide, CRCD, 78354 Jouy-en-Josas, FranceE-mail: andrei.khodakov@univ-lille1.frAnnotationTwo different but complementary methods were used to study the kinetics of Fischer-Tropsch synthesis on cobalt supported catalysts. The first method focuses on the transientkinetic measurements and analysis of several elementary steps of Fischer-Tropsch synthesisover cobalt supported catalysts in a pulse fixed bed microreatcor. The second methodaddresses measuring and modeling intrinsic steady-state Fischer-Tropsch kinetics in a slurrystirred tank reactor. The results on the mechanism and kinetics of Fischer-Tropsch synthesisobtained by both methods are discussed in the paper.1. IntroductionFischer-Tropsch (FT) synthesis produces clean fuels from natural gas, coal and biomass.Cobalt supported catalysts have been particularly suitable for production of diesel fuels andwax. The efficient control of the selectivity is one of the key issues of FT synthesis. Thereaction proceeds at the conditions far from the equilibrium; the hydrocarbon selectivity isprincipally governed by the reaction kinetics. The reaction starts by chemisorption ofhydrogen and carbon monoxide followed by the formation of the first CH x monomer species.The reaction involves polymerization of surface CH x monomers. Linear α-olefins andparaffins are the primary products of FT synthesis. This scheme leads to the Anderson-Schulz-Flory (ASF) distribution of hydrocarbons. The secondary reactions lead to deviationsfrom ASF statistics, which are generally attributed to readsorption of α-olefins produced bythe FT reaction. This paper addresses two different methods to study the kinetics ofelementary steps of FT synthesis. The first method involves measuring and modeling transientresponses of carbon monoxide, hydrogen and reaction products in a pulse fixed bedmicroreactor. The second method is based on the steady-state kinetic studies of Fischer-Tropsch synthesis in a slurry stirred tank reactor.2. ExperimentalFor transient experiments in a pulse microreactor 10 wt. % cobalt catalysts were preparedby impregnation of silica or alumina using aqueous solution of cobalt nitrate or cobalt acetate.Dihydrogen hexachloroplatinate (IV) and ruthenium nitrosyl nitrate were added to the160