مطالعه عددي پديده هاي انتقال و احتراق در گازي كردن سوخت چوب

In gasification and combustion of biomass including wood, the main problem is the transfer of alkali compounds on the surfaces of the energy systems. The deposition of these compounds on the surfaces may lead to erosion and corrosion of surfaces as well as flow blockage and vibrations. In this paper the gasification and combustion of wood particles in cyclone gasifiers are simulated and the parameters that affect on the reduction of alkali compound transfer to energy systems are studied. The Euelerian conservation equations of the gas phase are solved using the control volume approach and the Lagrangian equations of motion of solid particles are solved by a step-wise integration. The verifying of results including the distributions of temperature and chemical species, devolatilization time, particle trajectory and residence time of wood particles shows that the equivalence ratios ranging from 0.15 to 0.4 and particle sizes from 150 to 600 microns, provide satisfactory conditions for reduction alkali compounds and effective combustion of particles. Comparisons between predicted and measured results show good agreement.