Influence of ultrasonic waves on the gas-solid flow and the solids dispersion in a CFB riser: Numerical and experimental study

Abstract

There are different ways to enhance the solids dispersion in the CFB risers, and the use of acoustic waves for this purpose is under-explored. In this context, a CFB-based design of experiments was proposed to investigate the influence of lower ultrasonic frequency and high intensity on the solids dispersion in a lab-scale CFB riser using Geldart B particles fluidized by ambient air at 5.7 m/s, with a solid mass flux of 1.60 kg/m2∙s. Maps of solids dispersion were developed in a range of sound frequencies from 20 kHz to 100 kHz and input power from 10 W to 50 W. The results indicated that ultrasounds enhanced solids distribution and the best dispersion was reached with 20 kHz and input power between 10 W and 50 W. It contributes to reducing cluster formation in the bottom region of the CFB riser and avoids the development of the core-annulus profile.