Preparation of fly ash Ca(OH)(2) sorbents by pressure hydration for SO2 removal

Reactive sorbents for SO2 removal from humidified flue gas were prepared fr om fly ash-Ca(OH)(2) mixtures using the pressure hydration technique. The f ly ash samples were taken from three different coal-fired power plants in T urkey. The fly ash/Ca(OH)(2) weight ratio, hydration time, and temperature were varied during the sorbent preparation step. Effects of these variation s on the physical properties of activated sorbents were investigated. A sta tistical design technique was applied by use of a two-level factorial desig n matrix to interpret experimental results. It was found that increasing th e temperature and fly ash/Ca(OH)(2) weight ratio caused a decrease in the t otal surface area of sorbents. However, surface area values of sorbents wer e not generally affected by the hydration time variation. Finally, fly ash- Ca(OH)(2) sorbents prepared at the optimum hydration conditions were sulpha ted at 338 K with a synthetic gaseous mixture containing 5000 ppm SO2 and 5 5% relative humidity.