COMPARISON OF 2-PHASE UPFLOW AND DOWNFLOW FIXED-BED REACTORS PERFORMANCE - CATALYTIC SO2 OXIDATION

A time- and space-dependent model based on the piston-dispersion-excha nge model for liquid flow was developed to analyze the performance of two-phase upflow and downflow fixed bed reactors and was applied to th e catalytic SO2 oxidation. The hydrodynamic parameters were determined from residence time distribution measurements, using an imperfect pul se method for time-domain analysis of nonideal pulse tracer response. A transient diffusion model of the tracer in the porous particle coupl ed with the PDE model was used to interpret the obtained RTD curves. G as-liquid mass transfer parameters were determined by a stationary met hod based on the least square fit of the calculated concentration prof iles in gas phase to the experimental values, It is shown that two-pha se downflow fixed bed reactor performs better at low liquid flow rates , while two-phase upflow performs better at high liquid flow rates.