Abstract
Sand is the most important part in the combustion process of fluidised bed combustor (FBC). The size of the sand particle has an effect on the fluidisation phenomenon, thus having an impact on the heat transfer process that occurs in bed material. By using wood pellet as fuel, there is a possibility of fluidisation phenomenon which is unfavorable due to the formation of sand agglomeration. This is proven in an experiment where 100 % of wood pellet was used as fuel for start-up and other things. It was difficult for the bed to achieve stability in a temperature range of 500 - 700 °C even though this range of temperature is a performance criterion in FBC to generate a self-sustain condition. To counter agglomeration, the easiest method of operational measurements was by mixing wood pellet with other fuels. This method is called co- combustion or co-feeding. In this experiment, we used coconut shells as co-combustion fuel. To observe the agglomeration, the temperature was measured in three points, where two of them were located above the distributor plate at a height of 3.5 cm and 24.5 cm. The result shows that both fuel mixtures were able to reduce and eliminate the agglomeration. In a mixture of coconut shells, the best result was obtained in the mixture of 30 % coconut shells.
