A NOVEL PERIODIC REACTOR FOR SCRUBBING SO2 FROM INDUSTRIAL STACK GASES

A laboratory-scale investigation of SO2 scrubbing was carried out in t wo parts: (1) screening of catalysts, and (2) continuous runs in a 50 mm (diameter) x 190 mm trickle bed using periodic interruption ofliqui d flow. The screening study disclosed that impregnating activated carb ons with platinum substantially increased the activity for SO2 oxidati on. However, the continuous runs indicated that 95% SO2 removal from s imulated stack gas can be achieved with either an activated carbon or with one impregnated with Pt. Scrubbing at 80 degrees C removes much m ore SO2 from the gas phase than at room temperature and converts SO2 t o H2SO4. Cycle periods should exceed 30 min and the duration of liquid Row through the trickle bed should be greater than 3 min. Projecting results to an industrial scale indicates that the impregnated carbon s hould be chosen if a high by-product sulfuric acid strength is needed. For installations handling large gas volumes, activated carbon is the preferred catalyst and only weak sulfuric acid can be produced. The a dvantage of periodic flow interruption appears to be higher by product acid strength and lower pressure drop in the scrubbing operation.