Dispersion Trajectory and Dynamics of Particles Injected from the Sidewall in the Gas–Solid Fluidized Bed

Abstract

The dispersion trajectory and dynamics of particles injected from the sidewall were investigated in a pseudo-two-dimensional fluidized bed based on digital image analysis, and the effect of the injection position on the dispersion trajectory was revealed. Image analysis showed that the dispersion trajectory could be divided into two stages, including the initial dispersion stage and the bed dispersion stage, and the former one was affected by the injection position severely. As injected near the gas distributor (distributor zone), it showed the central-upward trajectory; when injected in the middle area, it was the sidewall-downward trajectory; while as injected near the bed height (splash zone), it demonstrated as the lateral-dispersion coupled sidewall-downward trajectory. As a result, the dispersion time was the smallest when injected near the gas distributor. Furthermore, the effect of the superficial gas velocity was also considered when particles were injected at different heights. When injected close to the gas distributor, the initial dispersion stage was negligible and the bed dispersion stage decreased with increasing superficial gas velocity. When injected far away from the gas distributor, duration times of both stages decreased with the superficial gas velocity increasing.