SO2 OXIDATION IN A REVERSE-FLOW REACTOR - INFLUENCE OF A VANADIUM CATALYST DYNAMIC PROPERTIES

The process of sulphur dioxide oxidation over vanadium oxide catalyst in a fixed-bed reactor with periodic gas flow reversal was analyzed on the basis of a mathematical model. The mathematical description of unsteady-state processes in the reactor includes the dynamic model of SO2 oxidation in the melt of active component of catalyst developed recently by Balzhinimaev and Ivanov. It describes both the main catalytic reaction steps and side processes involving changes in the catalyst state. Estimation of time scales of various unsteady-state processes in the catalyst and fixed-bed reactor allowed to include only essential dynamic elements of the model. The moving profiles of the temperature, gas phase composition and catalyst phase intermediate concentrations are calculated and analyzed. The effects of various factors governing the catalyst state dynamics are elucidated for performance parameters, such as cycle-average SO2 conversion and maximum temperature in the catalyst bed. Results obtained provide a background for an explanation of the discrepancies between the predictions for the process performance using a steady state kinetic model and experimental results obtained from pilot and industrial units.