INVESTIGATION OF SO2 OXIDATION RATES IN TRICKLE BED REACTORS OPERATING AT LOW LIQUID FLOW-RATES

Published measurements of the rates of sulfur dioxide oxidation over active carbon in trickle-bed reactors exhibit conflicting behaviour as the water flow is decreased. Experiments were undertaken to find the source of this unexpected behaviour. These indicate that at low liquid flow rates, steady state is attained remarkably slowly, requiring up to 5 h. During this period, rates continually increase. From their descriptions of experimental procedures, some investigators assumed steady state to exist after a set time interval, regardless of liquid flow rate. This seems to explain the conflicting measurements.