Enhancement of Sulfation of CaO by Fe2O3in the Oxidative-Sorption Process for SO2Removal Using Fe2O3/CaO Binary Sorbents

Abstract For the oxidative sorption of SO2 using Fe2O3/CaO binary sorbents prepared by the usual impregnation method, reactivities and capacities for SO2 removal have been investigated with TG measurements at temperatures near 500 °C in a stream of air containing SO2 in concentration from 2 to 11%. Both the reactivities and the capacities of the sorbents were exceedingly enhanced by addition of Fe2O3 into CaO such small amounts as 0.1–0.8wt%, and further Fe2O3-loading over 1.0wt% resulted in a lowering in promoting effects. The changes in surface area and pore-size distribution with a variation of Fe2O3 content were also measured in order to discuss the correlation between chemical reactivity for SO2 removal and physical property of the Fe2O3/CaO sorbents. In addition, Fe2O3–CaO mechanically mixed sorbents and the other binary sorbents such as Fe2O3/MgO or V2O5/CaO were tested to compare with the Fe2O3/CaO sorbents.