Adsorption of SO2 from sintering flue gas by alkali modified fly ash in electrostatic precipitator

In this study, fly ash was modified with NaOH and Ca(OH)(2) and discussed the feasibility of its adsorption of SO2 from flue gas in electrostatic precipitator (ESP). The optimal modification conditions were determined by comparing the changes of SO2 adsorption performance of different modified fly ashes in flue gas. The effect of modification and adsorption of SO2 before and after on the electrical conductivity of fly ash was investigated by testing the specific resistance characteristics. The results showed that when the solid-liquid ratio was 1:5 and the modification time was 90 min, the Ca(OH)(2) modified fly ash has the best adsorption capacity for SO2 in flue gas, and the adsorption capacity of SO2 was 31.44 mg/g. Compared with the raw fly ash, the adsorption capacity increased by 141.85%. The modified fly ash has better conductivity than that before modification, and the peak-specific resistance can be reduced by two orders of magnitude. After SO2 adsorption, the specific resistance of alkali modified fly ash was increased, but it was still lower than that of the raw fly ash, which was favorable to be removed in the dust removal stage.

Automated summary

This study investigates the modification of fly ash with NaOH and Ca(OH)(2) and discusses its feasibility in adsorbing SO2 from flue gas in an electrostatic precipitator (ESP). The optimal modification conditions are determined by comparing the changes in SO2 adsorption performance of different modified fly ashes. The effect of modification and adsorption of SO2 on the electrical conductivity of fly ash is also examined. The results show that Ca(OH)(2) modified fly ash has the best adsorption capacity for SO2 in flue gas, with an adsorption capacity of 31.44 mg/g, representing a 141.85% increase compared to raw fly ash. The modified fly ash exhibits improved conductivity and can be effectively removed during the dust removal stage.