SINGLE-EVENT KINETICS OF CATALYTIC CRACKING

A fundamental kinetic model of catalytic cracking on zeolite catalysts has been developed. The complete network of elementary steps of the carbenium ion reaction intermediates is generated by means of an algorithm based on Boolean relation matrices. Elementary steps on Lewis and Bronsted sites are taken into consideration. Single-event rate parameters are estimated for the cracking of paraffins, accounting for the thermodynamic constraints. Because of their fundamental chemical nature, these rate parameters are independent of the feedstock. It is shown how the model can be adapted to the availability of a lumped analysis of the feedstock. Lumped Hougen-Watson rate equations, incorporating a maximum of information about the complex reaction networks, are derived. The lumped rate parameters are reconstructed from the fundamental kinetics by means of multiplication with lumping coefficients.