This work presents a comprehensive approach to estimate kinetic parameters when the involved reactions contain lumped chemical species. This approach is based on representing rate constants with a continuous probability distribution function. In particular, the beta function is used to estimate kinetic parameters in catalytic cracking reactions. Thus, several kinetic models for the catalytic process containing different number of lumps are selected and a discretization procedure is carried out to estimate the corresponding kinetic parameters. The kinetic representation based on the probability distribution substantially reduces the computational and experimental effort involved in the numerical evaluation of kinetic parameters. Published by Elsevier Ltd.