Combustion

Flue gas

Chemistry

Catalysis

Boiler (water heating)

Organic chemistry

Selective catalytic reduction

Inorganic chemistry

Waste management

Flue-gas desulfurization

Engineering

Fuel

SO3 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 SO2 to SO3 (SO2/SO3) during SCR process were studied and evaluated, which included the effects of flue gas composition and SCR catalyst components on the conversion of SO2/SO3. SO3 was trapped by the condensation and isopropanol absorption method, and SO42− concentration was detected by spectrophotometer. The results showed that a certain concentration of NH3 in the flue gas significantly promoted the conversion rate, but when NH3 and NO coexisted, NO inhibited the catalytic action of NH3, while NO itself and O2 had small effect on the conversion rate. Besides, the conversion rate of SO2 increased with the increase of Ti and V content in the catalyst, and SiO2 and BaO abated the catalytic oxidation of SO2, while WO3 promoted the formation of SO3.

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