LAUSR

ABSTRACT In the present work, based on the traditional air dense medium fluidized bed (ADMFB), the constant gas velocity was substituted with pulsating velocity to propose pulsating fluidized bed (PFB) to investigate the distinct advantages in separating the fine coal particles in PFB over ADMFB. In this regard, the two-fluid model (TFM) was used to study the formation of bubbles, the distribution of density, and the gas-solid motion in PFB. The simulation results showed that lower bed height could decrease the energies of collision and mergers. The reason why the diameter of bubbles in PFB was much smaller than ADMFB was that the pulsating mechanism could effectively cut off the aggregation channels of gas below the lower pressure domain of bubbles. Moreover, the dense medium particles presented the upward movement in the middle of the bed and downward movement near the side walls. The distribution of bed density in PFB showed more stable condition from the spatial and temporal aspects. Finally, based on the orthogonal experiments, a correlation for estimating the fluctuations in bed density was established to illustrate the optimum values for bed height and pulsation frequency for airflow, which had values of approximately 100 mm and 2.0 hz, respectively.