Modeling of a radial-flow moving-bed reactor for dehydrogenation of isobutane

A mathematical model for the performance of a radial-flow moving-bed reactor for dehydrogenation of light paraffins was developed. Assuming relevant kinetic expressions for the main reaction and catalyst deactivation, the kinetic parameters were obtained through lab-scale fixed-bed reactor testing using the integral method of analysis. The conversion was found to be a function of a dimensionless decay time, i.e., the ratio of a “catalyst deactivation time constant” to the residence time of the catalyst within the reactor. For a large dimensionless decay time (negligible catalyst decay), the performance equation approached that of a simple packed-bed reactor. The predictions of the model were compared with those of a commercial unit, and fair agreements were observed.