Investigation of the Combustion Performance of Residues from Vineyards and Processing Industry via Fluidized Bed Experiments, Factorial Design, and Modeling

Abstract

ABSTRACTResidues from vineyards and wine/spirits industry, as being abundant in South European countries, were investigated for their application in thermal processes for energy production. The thermal behavior and the reactivity of the fuels and their blends were determined by thermogravimetric analysis tests. The combustion performance of the residues in terms of efficiency and emissions was studied by carrying out experiments in a fluidized bed unit. The effects of excess air ratio, fuel loading, and blending ratio were examined and a factorial design and modeling was developed in order to provide optimal values of process variables for minimizing emissions. The results showed that CO emissions were low, SO2 emissions were negligible, while NOx emissions from grape husks were high. A mitigation of CO and NOx levels could be achieved by decreasing excess air from 50% to 30% or reducing reactor loading. By increasing the percentage of grape husks in the mixtures, flue gas emissions were increased, however, combustion efficiency was maintained at high levels. Factorial design analysis and modeling indicated that the optimum combustion and emission performance was accomplished when the combustor was fed with vine shoots at reduced loading and excess air below 40%.