29. Studies on SO_2 removal in a PFBC plant

Abstract

Characteristics of SO_2 emission of a PFBC (Pressurized Fluidized Bed Combustion) were studied with the data of a test apparatus and a commercial plant. Concentration of SO_2 at the furnace exit decreased as oxygen concentration and bed temperature increased. And SO_2 concentration decreased with decreasing load of the plant. This load dependence was thought to be caused by the high CaO concentration in bed material (BM). As the load decreased, CO_2 partial pressure decreased and low CO_2 partial pressure accelerated a production of CaO from CaCO_3. On the other hand, gradual change of SO_2 removal was observed in the operation. This phenomenon occurred because of the change of the condition of BM surfaces.