Numerical analysis of wood combustion in an updraft gasifier

Waste wood, a renewable energy source is used as feedstock for Universiti Teknologi Malaysia´s newly-developed two-stage incinerator system. The research goals are to optimize the operation of the thermal system, to improve its combustion efficiency and to minimize its pollutants formation. During experimental work, the feedstock will undergo four different processes; drying, devolatilisation, gasification and combustion. For optimum operating condition, where the gasification efficiency is 95.53%, the moisture content of the fuel is best set at 17%; giving outlet operating temperature of 550°C and exhaust gas concentrations with 66 ppm of NO. In line to the experimental work, a computational fluid dynamics software FLUENT is used to simulate the performance of the primary chamber at optimum operating condition. A steady state model is formulated for the updraft fixed bed reactor. Here the predicted optimum gasification efficiency stands at 95.49% with NO is 53.7 ppm.