Fluidized bed combustion of residues from oranges’ plantations and processing

Some of the major agricultural residues of Mediterranean countries, orange tree pruning, leaves and peels and their blends, were evaluated for heat production. The experiments were conducted in a lab-scale fluidized bed facility. Temperature distributions along the reactor and flue gas emissions were measured at different excess air ratios, fuel feed rates and fuel mixing ratios. The combustion performance of the residues was studied in terms of emissions and efficiency. The results showed that a higher excess air ratio or feed rate improved combustion efficiency. Flue gas emissions were not significantly affected, when the excess air factor λ varied between 1.4 and 1.7. CO emissions were found to increase with volatiles and ash contents of the fuels. A large amount of volatiles was burnt in the freeboard. SO2 emissions were negligible, while NOx emissions were generally high. Of the biomass fuels tested, orange tree pruning offered the higher efficiency and was the most environmentally friendly.