Effects of Excess Air and Energy Fraction on Heat Transfer for Co-firing of Eucalyptus Bark and Peanut Shell Blended Fuel in a Twin-Cyclonic Swirling Fluidized-Bed Combustor

Biomass plays an important role in mitigating greenhouse gas (GHG) emissions. However, the major problem in using biomass is that inconsistent amounts are available throughout the year. The use of mixed fuels is one way to solve this problem. Based on the lumped system analysis method, this experimental study investigated the effects of excess air ( EA ) and energy fraction on the heat transfer coefficients of co-firing eucalyptus bark and peanut shell in a twin-cyclonic swirling fluidized-bed combustor. The blended fuel was fired at a fixed heat rate for various energy fractions of secondary fuel ( EF 2 ) and EA . The radial and axial heat transfer coefficients were observed: the average heat transfer coefficient of each operating condition showed significant effects for EA , while the effect for EF 2 was not obvious. The heat transfer coefficient could be improved by up to 11% in the bed region and by as much as 22% in the freeboard area when EA was increased from 40–80%.