Pulsed gas–solid fluidized beds can effectively separate fine coal, and bubbles play an important role in creating suitable separation conditions. The present study performed statistical and image analyses of the evolution of bubbles in a two-dimensional pulsed gas–solid fluidized bed using a high-speed dynamic camera. The effects of apparent gas velocity, pulsation frequency and particle size on bubble characteristics and bed expansion were analyzed. The results indicate that, when a fluctuation frequency is added, the expansion height of the bed increases, the effect of attachment to the bed wall decreases, the leading diameter and rising velocity of the bubbles both decrease and the degree of bubble deformation increases. These trends are also more obvious for fine particles. These findings demonstrate that a high density pulsed gas–solid fluidized bed can effectively combine gases and solids to produce a uniform, stable mixture. The bubble diameter and rising velocity were also simulated in the present work, and the relationship between the two was established using a fitting model with an error within 5%. This model provides an effective means of predicting bubble velocity as well as studying the distribution of the bubble phase and improving the stability of the bed density.

脉冲气固流化床可以有效地分离细煤，而气泡在创造合适的分离条件中起着重要的作用。本研究使用高速动态相机对二维脉冲气固流化床中气泡的演化进行了统计和图像分析。分析了表观气体速度，脉动频率和粒径对气泡特性和床膨胀的影响。结果表明，当增加波动频率时，床的膨胀高度增加，附着到床壁上的作用减小，气泡的前导直径和上升速度都减小，气泡变形程度增加。对于细颗粒，这些趋势也更加明显。这些发现表明，高密度脉冲气固流化床可以有效地将气体和固体混合，产生均匀，稳定的混合物。在当前工作中还模拟了气泡直径和上升速度，并使用误差在5％以内的拟合模型建立了两者之间的关系。该模型提供了预测气泡速度以及研究气泡相分布和提高床密度稳定性的有效手段。