Feasibility study of acoustic agglomeration of fly ash in shaped resonators

Abstract

An interesting method for controlling fine particulate emission is acoustic agglomeration. Acoustic agglomeration is a process where fine particles coalesce and grow into bigger particles when they are subjected to a high intensity sound field. As a result the particle size distribution shifts to larger sizes. Acoustic agglomeration can thus be used as a preconditioner prior to a conventional filter and improve the overall capture rate of the filter. An experimental study was performed to evaluate the potential of a new high intensity acoustics technology, resonant macrosonic synthesis (RMS), to agglomerate fly ash. RMS allows the generation of very high amplitude shock-free acoustic standing waves within shaped resonators. Experiments were performed in a football shaped resonator at 570 Hz under varying fly ash loadings and sound pressure levels. Particle size measurements were obtained using a laser diffraction particle-sizing instrument. Reduction of fine particulate matter (diameter of particles less than 5 micron) of up to 50% has been achieved. [Work supported by Dominion Corp.]