Influenced factors study and evaluation for SO2/SO3 conversion rate in SCR process

SO 3 generated in coal-fired boiler and selective catalytic reduction (SCR) process has become a significant problem due to its adverse effects on boiler facilities and air environment. The factors influenced conversion rate of SO 2 to SO 3 (SO 2 /SO 3 ) during SCR process were studied and evaluated, which included the effects of flue gas composition and SCR catalyst components on the conversion of SO 2 /SO 3 . SO 3 was trapped by the condensation and isopropanol absorption method, and SO 4 2− concentration was detected by spectrophotometer. The results showed that a certain concentration of NH 3 in the flue gas significantly promoted the conversion rate, but when NH 3 and NO coexisted, NO inhibited the catalytic action of NH 3 , while NO itself and O 2 had small effect on the conversion rate. Besides, the conversion rate of SO 2 increased with the increase of Ti and V content in the catalyst, and SiO 2 and BaO abated the catalytic oxidation of SO 2 , while WO 3 promoted the formation of SO 3 .