In the present work, sound-assisted fluidized bed combustion has been investigated by means of a 41mm laboratory scale apparatus fed with combustible powders of different fuels: a tyre derived fuel, a lignite and a petroleum coke. The experiments aim at studying the effect of sound intensity and frequency on carbon conversion of elutriable fines generally produced during fluidized bed combustion of solid fuels. The effectiveness of sound application is evaluated in terms of effects on bed carbon loading, carbon elutriation rate, combustion time and degree of conversion of fixed carbon. Experimental data prove that application of acoustic fields of appropriate intensity and frequency may: increase bed carbon loading and combustion time, reduce elutriation of carbon fines and increase efficiency of fixed carbon conversion. The effects are different for each fuel depending on its characteristics. A simplified model of sound-assisted fluidized bed has been developed. The model has been validated by comparing the experimental optimum intensity and frequency with calculated values of minimum intensity and optimum frequency. The present formulation of the model is useful for the design of the acoustic field to be used in sound-assisted fluidized bed combustors.
