Abstract

A kinetic model to describe the catalytic pyrolysis of tars is proposed and validated through the experimental pyrolysis of three tars of different characteristics and origin; calcined limestone (11 m2/g) was used as catalyst. Experiments were carried out in a catalytic fixed bed reactor. The model assumes that tars are composed of two pseudo-components, described as heavy and light tars, which can be experimentally determined by a split temperature. Tar pyrolysis is described by two simultaneous chemical reactions; catalyst deactivation due to carbon deposition is also considered. Expressions for product concentrations as functions of residence time, selectivity and deactivation were obtained and the kinetic parameters evaluated.