III International Conference

THE EFFECT OF THE SUPPORT ON THE PERFORMANCE OF Со/Al 2 O 3CATALYST IN FISCHER-TROPSCH SYNTHESISPP-II-79Mikhailova Y.V., Svidersky S.A., Sineva L.V., Mishin I.V. 1 , Mikhailov M.N., Krylova A.Y.United research and development centre, Moscow, Russia1 N.D. Zelinsky Institute of organic chemistry RAS, Moscow, RussiaE-mail: MikhailovaYV@yrd.ruThe Со/Al 2 O 3 catalysts of Fischer-Tropsch synthesis are efficient in producing heavyhydrocarbons. Catalytic properties of such systems depend on the nature of the precursor(gibbsite, boehmite, bayerite) used to produce the support.To examine the effect of the nature of the aluminum compound on the performance of theСо/Al 2 O 3 catalyst, the gibbsite, boehmite and bayerite based samples (30%Со/Al 2 O 3 ) weretested in Fischer-Tropsch synthesis. The catalytic results were compared with phasecomposition of Al 2 O 3 support as indicated by the XRD study.The Al 2 O 3 support was prepared by calcining aluminum hydroxide (gibbsite, boehmite,bayerite). The 30%Со/Al 2 O 3 catalysts were prepared by triple impregnation of the support byCo(NO 3 ) 2·6H 2 O water solution. Hydrocarbon synthesis was carried out in a fixed-bed reactorat atmospheric pressure. Before synthesis all samples were pre-reduced in hydrogen flow.The XRD study showed that the nature of aluminum hydroxide (gibbsite, boehmite,bayerite) has a marked effect on the sample phase composition. In particular, boehmite basedsamples contain much more γ-Al 2 O 3 , than gibbsite based support, in which most of aluminaoccurs as amorphous phase. Results obtained by XRD correlate with catalytic data describedbelow.The catalytic tests confirmed that aluminum hydroxide structure in 30%Со/Al 2 O 3 catalystsupport influences the yield of С 5+ hydrocarbons. The С 5+ hydrocarbons yield decreases in arow: gibbsite (105 g/m 3 ) > boehmite (96 g/m 3 ) > bayerite (86 g/m 3 ). The С 5+ hydrocarbonsselectivity varied insignificantly (85-90 %). All samples are characterized by lower methaneselectivity (4-7 %). SF alpha values for all samples were 0.95-0.97. Fractional composition ofliquid hydrocarbons depends on the aluminum precursor nature. For the gibbsite-basedcatalyst the contribution from C 19+ fraction was essentially higher than in the case of theboehmite and bayerite based samples.Hence, the nature of aluminum hydroxide in 30%Co/Al 2 O 3 catalyst influences both theactivity and selectivity of the catalyst in the hydrocarbon synthesis from СО and Н 2 . The307