ELUCIDATING THE DRIVING FACTORS IN SULFUR TRIOXIDE FORMATION UNDER SIMULATED ACTUAL ULTRA-LOW EMISSION PROCESS

Current flue gas pollution control technologies compliant with ultra-low emission standards exhibit limited effectiveness in removing sulfur trioxide (SO 3 )—a key condensable particulate matter (CPM) precursor—necessitating high-efficiency, low-consumption control strategies. To address the poorly elucidated formation mechanisms of SO 3 across ultra-low emission systems, particularly within the SCR+WFGD process chain, this study employed experimental simulations where SO 3 was prepared via the contact process and quantified through controlled condensation coupled with sulfate titration. Catalytic oxidation experiments on cesium-doped V 2 O 5 in a temperature-controlled fixed-bed reactor under simulated actual flue gas revealed reaction temperature as the governing factor for SO 3 conversion, achieving peak efficiency at 485–505°C. Whereas SO 2 concentration exerted non-dominant effects due to sustained catalytic stability, space velocity proved negligible under high-temperature regimes. These mechanistic insights establish fundamental pathways for developing targeted SO 3 mitigation technologies.