Bed Particle Agglomeration and Defluidization in the Rubber Wood and Coir-Fired Fluidized Bed

The behaviors of the bed particle agglomeration and the bed defluidization during the fluidized bed combustion of the rubber wood and the coir were experimentally studied. This work focused on (1) the effects of the bed operating variables on the bed agglomeration tendency and (2) the behaviors of the fuel inorganic elements and the governing mechanisms associated the bed agglomeration. During the combustion, the fluidized bed underwent the defluidization from partial to complete by the growth of the bed particles and the accumulation of the agglomerates. The fuel composition was the significant effect. The defluidization was promoted by the increasing bed temperature and bed particle size, and the decreasing air velocity. The morphological and chemical analyses revealed that the molten K-silicates formed via the reactions between the fuel's potassium and silicon of the bed particle contributed towards the bed agglomeration. The migration of the inorganic compounds from the fuel particle to the bed particle was likely dominated by the deposition of the released gaseous/aerosol inorganic species. The thermodynamic examination corroborated that the K-Si adhesive materials which presented as the liquid phase at the observed bed conditions caused the agglomeration. The large melt fractions in the materials were shown.