Kinetic characteristics of the particles in a dense-phase pulsed fluidized bed for dry beneficiation

Coal is one of the most important primary energy sources all over the world. Dry coal beneficiation is a hot topic in the mineral processing field because of severe environmental pollution and shortage of water resources. A dense-phase pulsed fluidized bed (DPPFB) is proposed for the dry coal beneficiation of fine coal; an active pulsating airflow was introduced into an air dense medium fluidized bed (ADMFB). In this study, the kinetic characteristics of the particles in a DPPFB were investigated by computational particle fluid dynamics. The results show that the bubbles present in the DPPFB were much smaller than those in the ADMFB, and the motion of the dilute-phase region replaced the motion of the large bubbles. Because of the action of the pulsating airflow, the motion of the heavy medium became uniform and steady. The back-mixing phenomenon caused by the circulation motion of the heavy medium was suppressed significantly.