Flow-field analysis of a continuous gas–solid separation fluidized bed equipped with a moving scraper

Abstract Continuous gas–solid separation fluidized beds are one of the most widely used practical operation units for the dry separation of coal in China, particularly in Northwest China, and they can effectively promote the efficient and clean utilization of raw coal. In a continuous gas–solid separation fluidized bed, the bed flow field is the concrete manifestation of the fluidization characteristics. However, the complexity of the flow field increases under the action of a moving scraper. In this study, a combination of computational fluid dynamics (CFD) simulations and experimental measurements was used to study the changes in the flow field of a fluidized bed. The results showed that when the scraper moved, the local flow field (mainly characterized by the movement of medium particles) near the scraper was affected not only by the common airflow or bubbles, but also by the lateral driving force of the scraper. When the scraper speed was vl