A study in the swirling fluidizing pattern

An innovative swirling fluidizing pattern generated by a multi-horizontal nozzle distributor was developed to minimize the axial momentum of fluidizing air and to provide momentum in both the radial and tangential directions. Experiments in pressure fluctuations and fines elutriation in the fluidized-bed system were conducted in 0.29-m I.D. and 0.19-m I.D. fluidized-bed cold models respectively to investigate the influence of the fluidizing pattern. The performances of the "swirling fluidizing pattern" and the conventional "axial fluidizing pattern" caused by a perforated plate were compared. In pressure fluctuation experiments, the pressure signals within the bed were converted into the frequency spectra using a Fast Fourier Transform (FFT) to proceed the spectral analysis. Effects of superficial air velocity, static bed height and distributor open-area ratio were taken into account. At a low nozzle air-discharge velocity, a stable concentration of fines within the bed would be attained. The first-order elutriation rate equation cannot describe the elutriation behavior of fines under a swirling fluidizing pattern, except at an extremely high air-discharge velocity. The swirling fluidizing pattern proved to produce a remarkable improvement in both the fluidization quality and elutriation reduction.