Formation of a ceramic structure of promoted iron oxide catalyst

Abstract

The paper concerns with the mechanism of the promoters influence on the ceramic structure of the iron oxide catalyst for the dehydrogenation of olefin and alkylaromatic hydrocarbons. The research shows the dynamics of changes in the porous structure of alloyed and unalloyed catalysts as a result of heat treatment in air at several temperatures significantly exceeding the operating temperature. Moreover, the paper presents data on the mechanical strength of alloyed and unalloyed model catalysts. Indeed, the particles are sintered to each other at the contact points of the globules forming a mechanically strong and thermally stable framework. However, the particles are sintered to each other at the contact points of the globules forming. Supposedly, potassium performs the function of a kind of flux. It lowers the temperature of the melting phase formation, which ensures a strong sintering of the ceramic material (catalyst) particles to each other. Hereby, there is a formation of a stable framework without a noticeable reduction of the catalyst working surface. The addition of zirconium oxide as an alloying agent provides an increase in the depth and degree of annealing of imperfections during the restructuring of the catalyst structure. Additionally, it provides the redistribution of the released energy. This assumption is confirmed by increasing of the alloyed catalyst granules mechanical strength. The results of research can be used for development and modification of iron-oxide catalysts for dehydrogenation of olefinic and alkylaromatic hydrocarbons.