Numerical Simulation of Acoustic Agglomeration and Experimental Verification

Abstract

Acoustic agglomeration is proposed as an intermediate treatment in the flue gas cleanup train of the effluents from coal burning power plants. Acoustic agglomeration causes the micron and submicron sized particles to collide, adhere and form large particles which can be more efficiently removed from the flue gases with particle removal devices. This paper describes the results of acoustic agglomeration tests of coal fly-ash aerosols in a 200-mm dia device at acoustic levels from 140 to 160 dB, frequencies in the 2–3 kHz range and mass loadings in the 1 to 30 g/m3 range with initial log-normal particle size distributions having geometric mean diameters of about 5 micrometers. The primary thrust of the paper is to present a numerical simulation model of the acoustic agglomeration process. The model is based on the recently proven assumption of complete fillup of the agglomeration volume and neglects the effects of gravitational settling, Brownian motion, and acoustically generated turbulence. Good agreement is found between the model predictions and the experimental data.