Preparation of active SO_2 sorbents from fly ash

摘要

Fly ash samples collected from three different coal fired power plants in Turkey were activated by hydration. Hydration experiments were carried out at different conditions; namely, at temperatures of 333 K and 363 K, time intervals of 4h and 8h and water/fly ash weight ratios of 15 and 20. Effect of hydration conditions on the physical properties of activated fly ashes were determined. It was found that increasing the temperature and hydration time caused an increase in the total surface area. However, surface area values of the fly ashes hydrated at the different water/fly ash weight ratios were not changed significantly. Also the physical properties of activated fly ashes were changed depending on their CaO and SiO_2 contents. Sulphur dioxide sorption capacities of the hydrated fly ashes were determined at 338 K and 55 % relative humidity. It was determined that, the total sulphation capacities were changed in the range between 0.54-0.93 mmole SO_2/g sorbent due to the differences in physical and chemical properties of the sorbents.