Sonic agglomeration of aerosol particles

Abstract

Carbon black was used to study the behavior of an aerosol in a sound field. The primary objective of this work was to determine the feasibility of using sonic agglomeration at low sound pressure levels (100 to 120 dB) to coagulate particles. If coagulation could be achieved, the larger particles could be collected in a subsequent removal device. Prediction of optimum conditions for maximum agglomeration was also an integral part of this analysis. Separate experiments to determine the effect of varying sound pressure level, frequency, particle mass loading in an air stream, and exposure time were conducted. Increasing the mass loading, sound pressure level and exposure time resulted in increased agglomerate size. For all tests using carbon black, optimum growth occurred at 3 kHz. It is noted that the mean particle diameter in a carbon black aerosol can be increased an order of magnitude using sonic agglomeration at low sound pressure levels suggesting that this mechanism can be used effectively in industrial processes.