Fluidized bed combustion of tyre derived fuel

Mechanistic aspects of the fluidized bed combustion of tyre derived fuel (TDF) have been analyzed both experimentally and theoretically. The time-resolved rates of carbon fines elutriation during the fluidized bed combustion of TDF have been measured during batch experiments in a bench scale reactor at 850 C, under different operating conditions. Experimental results indicated that both gas superficial velocity and oxygen partial pressure exert influence upon the overall fixed carbon combustion efficiency. The efficiency increases slightly with the oxygen concentration and significantly if the gas superficial velocity decreases. Experimental data are further analyzed in the framework of a fluidized bed combustor model especially suited for high-volatile solid fuels feedings. The model takes into account phenomena that assume particular importance with this kind of fuels, namely fuel particle fragmentation in the bed and combustibles segregation and postcombustion above the bed. Experimental and model results indicate that the efficiency of the fluidized bed combustion of TDF is controlled by the competition between combustion and entrainment of char fines and volatile matter released in the early stage of fuel conversion.