Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Computational Fluid Dynamics Simulation of Palm Kernel Shell Combustion in a Bubbling Fluidized Bed Combustor
by Nordiana O. Joseph, Ighodalo Osagie and Ajuwa I. Christopher

Abstract:
A computational fluid dynamics approach was applied to simulate the combustion characteristics of palm kernel shell (PKS) in a bubbling fluidized bed combustor (BFBC). The combustor was divided into two regions: the bed and the freeboard. The calculation of mass and energy fluxes from the bed provided the boundary conditions for the subsequent CFD analysis. The freeboard model implemented by means of FLUENT 6.3.26 was mainly concerned with employing the two-mixture fraction-pdf approach to track both the flue gases coming from the bed and the PKS fuel particles that did not burn in the bed but above it. The freeboard operation was simulated using PKS fuel feed rate of 7.32kg/hr for excess air ranging from 20% to 100%. The simulated temperature distribution along the freeboard axial height and the simulated CO2, CO and O2 concentrations from the combustor outlet were validated with experimental results. The model was also used to simulate and optimize the combustion characteristics of PKS for various operating conditions. Optimum operating condition obtained from the simulation were 94.2% combustion efficiency, 80% excess air, 7.98kg/hr fuel feed rate, 8150C bed temperature, fuel particle size range of 1.5mm � 6.0mm and 9ppm CO emissions at 6% O2 in the flue gases. Results indicate that CFD modeling is a promising way to analyze and optimize the performance of a full-scale fluidized bed combustor fed by biomass waste.

Keywords: CFD, excess air, combustion, palm kernel shell, simulation, temperature distribution

Download full paper