The fluidization quality of fine particles can be substantially improved by vibration caused by proper acoustic fields compared with an ordinary fluidized bed. To investigate the effect of acoustic field on hydrodynamic behaviour of solid particles is essential to understand the segregation behavior of fine coal particles (-6mm) with the aid of acoustic field. The effect of sound on the fluidization behaviour, including the variation of the bed pressure drop, the minimum fluidization gas velocity, the motion of bubbles and the bed collapse tests has been investigated under the application of acoustic fields of different intensities (110–130 dB) and frequencies (50–500 Hz). The results obtained show that the pressure drop after full fluidization is reduced due to the change of the particle arrangement structure induced by acoustic field. The fluidization quality of the bed can be enhanced by increasing sound pressure level. Unlike the effect of sound pressure level on fluidization quality, the sound frequency have more complicated influence that is not monotone changing relation, due to an oscillatory motion of both gas molecules and solid particle. The application of an acoustic wave, ensuring the stability of the bed density, can improve the separation performance of a gas-solid separation fluidized bed.
 

acoustic field, fluidization characteristics; frequency; sound pressure level; separation performance.