3.3. Bed material agglomeration The elemental analyses of the fly ash and bottom ash are given
in Table 3. The fly ash was collected from the baghouse. The ash deposited on the distributor after a 12 h combustion test was scooped up as the bottom ash. From Table 3, the concentrations
of alkali and alkaline-earth metals of fly ash are higher than those of the bottom ash. Owing to the accumulation of ash in the bed, the amount of alkali and alkaline-earth metals remained in the bed is increased with operating time. Meanwhile, there is no sign of bed agglomeration from 12 h combustion tests due to the lower operating temperatures in the bed.