The effectiveness factor of a catalyst pellet in the liquid-phase hydrogenation of styrene.

Abstract

The reaction characteristics of a catalyst pellet is examined in the liquid-phase hydrogenation of styrene in a stirred basket reactor. The catalyst used is a 0.5 % Pt-Al2O3 cylindrical pellet. The intrinsic kinetic expression of the Langmuir-Hinshelwood form is fashioned from the rate measurements in a stirred slurry reactor in which the finely crushed pellets are suspended. With the catalyst pellets the pore diffusion of hydrogen is observed to be significant. The effectiveness factor of the catalyst pellet is computed on the basis of a simplified theoretical model. The connection between the catalytic effectiveness factors obtained experimentally and theoretically makes it possible to estimate the effective diffusivity of hydrogen and the tortuosity factor of the catalyst pellet. The tortuosities ranging from 2.5 to 3.2, secured at the three temperature levels, are shown to be reasonable values for the pore diffusion within a liquid filled catalyst.