Advanced experimental analysis of the reaction of Ca(OH) 2 with HCl and SO 2 during the spray dry scrubbing process

Abstract

This work evaluates both the removal efficiencies of HCl and SO 2 at different points in a spray dryer using Ca(OH) 2 as the absorbent. The operating conditions were specified in terms of the temperature of the flue gas (200–300 °C), the HCl concentration (120–1000 ppm), the SO 2 concentration (150–500 ppm) and the amount of CaCl 2 added (10–30 wt.%). The experimental results showed that the SO 2 removal efficiencies were higher in the presence of HCl (120–500 ppm) than in the absence of HCl at 250 °C and 20% relative humidity (RH). However, the removal efficiency of SO 2 decreased as the HCl concentration increased. The removal efficiency of SO 2 also increased with the amount of CaCl 2 in the spray dryer.