화학공학소재연구정보센터
Fuel Processing Technology, Vol.88, No.9, 883-889, 2007
Effect of the addition of potassium and lithium in Pt-Sn/Al2O3 catalysts for the dehydrogenation of isobutane
Dehydrogenation of isobutane (iC(4)) to isobutene has recently received considerable attention because of the increasing demand for methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE), as additives for gasoline to increase the octane number and to substitute lead. Among several catalysts, Pt-Sn/gamma-Al2O3 catalyst is one of the most suitable ones. In this study, Pt-Sn, Pt-Sn-K and Pt-Sn-Li catalysts supported on gamma-Al2O3 have been investigated. The catalysts were prepared by co-impregnation using H2PtCl6, SnCl2 as the metal precursors and K2CrO4 and LiOH as the promoters. The obtained catalysts were characterized by TPR and XRD techniques. Reaction temperature, feed flow rate (Q), iC(4)/H-2 ratio and the catalyst type were the main variables that were investigated. Initially, primary experiments were carried out for the identification of the optimum range of operating variables, then, Taguchi's algorithm was employed to design the experiment. The results revealed that the Pt-Sn-K catalyst showed higher selectivity than Pt-Sn-Li. Under the optimum operating conditions i.e. at 550 degrees C, feed flow rate of 50 cm(3)/min and iC(4)/H-2 ratio of 1/3, selectivity toward isobutene of higher than 90% was achieved with the corresponding conversion values of about 15%. (c) 2007 Elsevier B.V. All rights reserved.