In order to prevent bed agglomeration during fluidized bed combustion processes, it is necessary to be model is able to predict the extent of agglomerate formation. In this study, a thermodynamic equilibrium used to predict the extent of agglomerate formation during fluidized bed combustion processes for various wastes and fuels. According to the simulation results, silicate melts such as sodium silicate melt and/or potassium silicate melt are the main components involved in bed agglomeration. The amounts of silicate melts predicted in the agglomeration and non-agglomeration groups were significantly different. An assessment criterion for predicting bed agglomeration in the fluidized bed combustion process was established using a thermodynamic equilibrium model. This criterion can be used as a fool for predicting the bed agglomeration potential in the fluidized bed combustion of various fuels. Therefore, it was found that control technology for bed agglomeration can be applied to the fluidized bed incineration of wastes and fuels based on the model simulation results.