Effect of Pt particle density on the hydrocracking of Fischer–Tropsch products over Pt-loaded zeolite catalysts prepared using water-in-oil microemulsions

Abstract

Water-in-oil (w/o) microemulsions are favorable for loading metal particles with a narrow size distribution. In the present paper, Pt-loaded β-type zeolite catalysts were prepared by immobilizing Pt complex particles, which were synthesized using w/o microemulsions, onto a zeolite support. Loaded Pt particles were within the size range of 4.8–5.9nm regardless of Pt content, whereas the Pt particle size of Pt-loaded catalysts prepared by the impregnation method increased from 1.7 to 13.1nm with increasing Pt content. The Pt particle density was estimated based on the characterization data assuming that the Pt particles were equally loaded onto the mesopores. The Pt particle density of the Pt-loaded zeolite catalysts prepared using w/o microemulsions was dependent on the Pt content at a nearly constant Pt particle size. The effect of the Pt particle density on hydrocracking performance, such as jet fuel yield, was investigated using an autoclave at an initial H2 pressure of 3MPa and 300°C in hydrocracking of the Fischer–Tropsch (FT) products over the Pt-loaded catalysts. When a constant amount of Pt was used, the maximum yield of corresponding jet fuel with carbon numbers of 9–15 (31.9%) was obtained at a Pt particle density of 0.9×1012m−2. At a constant catalyst weight, the corresponding jet fuel yield was maximized (27.8%) at a Pt particle density of 0.9×1012–1.1×1012m−2.