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1706676 
Journal Article 
OXIDATION OF SO2 TO SO3 OVER HONEYCOMB DENOXING CATALYSTS 
Svachula, J; Alemany, LJ; Ferlazzo, N; Forzatti, P; Tronconi, E; Bregani, F 
1993 
Yes 
Industrial and Engineering Chemistry Research
ISSN: 0888-5885
EISSN: 1520-5045 
32 
826-834 
A systematic study addressing the effects of the operating conditions (contact time, temperature), of feed composition (O2, SO2, H2O, NH3, NO(x), NH3 + NO(x), concentrations), and of catalyst design parameters (wall thickness, V content) in the oxidation Of SO2 to SO3 over honeycomb commercial-type DeNoxing catalysts is described. Data are presented which refer to transient behavior of the catalysts, indicating that long conditioning times are required associated with the buildup of surface sulfate species. The steady-state reaction rate is of variable order in SO2, the order increasing with SO2 concentration as long as this is below 200 ppm and then decreasing; it is asymptotically independent of oxygen, depressed by water, strongly inhibited by ammonia, and slightly enhanced by NO(x). The apparent activation energy changes from almost-equal-to 50 to almost-equal-to 20 kcal/mol on increasing the reaction temperature. A redox steady-state kinetic model is presented which accommodates qualitatively all of the observed effects. Once properly modified the same model has the potential to explain also transient effects during conditioning of the catalyst.