SO2 Removal by Limestone in a 71 MWe Pressurized Fluidized Bed Combustor

Part.1 Attrition and Fragmentation of Limestone

Abstract

Attrition and fragmentation of limestone in a 71MWe pressurized flu-idized bed combustor were estimated. Formation of Ca-containing fine particles due to attrition rate was calculated from the material balance of calcium in fly-ash which was captured at the exit of combustor. The average rate of attrition (rate of reduction of radius) of limestone was estimated to be approximately 1μm/h.
A population balance model was established to estimate the particle size distiribu-tion in the bed from the size distribution of fed limestone and attrition rate of bed materi-al in the bed. For some cases, the measured bed material size was far smaller than that of the estimated size distirbution. These results suggest that the fragmentation of lime-stone particle took place in the bed. The size distribution of limestone after fragmenta-tion was estimated so that the difference between estimated bed material size distribu-tion and measured size distribution should be minimized. The results indicates that the large limestone particles (greater than approximately 1mm) were broken into small parti-cles when they were fed into the combusotor.