High temperature desulfurization using fine sorbent particles under boiler injection conditions

The high temperature reaction of SO2 with CaO was investigated in three reactors: a thermogravimetric reactor (TGA), a volumetric reactor (VR) and an entrained flow reactor (EFR). Several natural limestones with super fine particles were used as sorbents. It was found that the reaction could be well characterized by a two-stage process. The initial stage was very fast and lasted about 0.1-0.4 s. The chemical kinetics of the reaction was studied and modelled. In addition to other parameters, such as particle size and Brunauer-Emmett-Teller (BET) surface area, the pore volume located in the larger pores (> 5.0 nm) was found to contribute somewhat to the high SO2 removal and CaO conversion. At Ca/S = 2 the SO2 removal was more than 90%