Alkali Migration during Corncob Combustion in Fluidized Bed

Corncob is combusted in a bench-scale atmospheric fluidized bed. Inductive Coupled Plasma Spectrometer (ICP-AES) is used to detect alkali content which moved into gas or remained in bed material in order to study the effect of bed temperature and air excess coefficient. The results show that bed temperature is the major factor on alkali migration, when bed temperature increases, alkali content into gas increases greatly, while alkali content in bed material decreases, potassium is more easily to vaporize into gas than sodium does during combustion. The result also shows that the proportion of water-solubility potassium in total potassium of bed material decreases also with the rise of temperature. The effect of air excess coefficient on alkali migration is less significant than temperature. When air excess coefficient increases from 1.12 to 1.35, alkali content in gas increased while alkali content in bed material decreased.