The performance of a circulating fluidized bed strongly depends on its parameter settings, including that of riser geometry. In this study, a laboratory-scale circulating fluidized bed with three different riser geometries (circular, square, and rectangular) that had the same cross-sectional area and height was operated under two static bed heights (20, and 35 cm). Electrical capacitance tomography was combined with differential pressure transducers and an optical-fiber probe to measure the solids’ volume fraction, differential pressure fluctuations, and radial particle concentration variations. Computational particle fluid dynamics simulations were also performed. The results showed that single bubbles appeared in the bottom region of the circular and square risers and double bubbles in the bottom region of the rectangular riser. The autocorrelation of capacitance signals was periodic for the circular and square risers and non-periodic for the rectangular riser. The radial particle concentration profiles showed a single-core annulus structure in the circular and square risers, but a double-core annulus structure along the long side and single-core annulus structure along the short side in the rectangular riser. Shannon entropy analysis showed that fluidization was less disordered and most predictable for the rectangular riser.

循环流化床的性能在很大程度上取决于其参数设置，包括提升管的几何形状。在这项研究中，在两个静态床高（20和35 cm）下运行具有三个相同横截面积和高度的立管几何形状（圆形，正方形和矩形）的实验室规模的循环流化床。电容层析成像与差压传感器和光纤探头相结合，可测量固体的体积分数，压差波动和径向颗粒浓度变化。还进行了计算粒子流体动力学模拟。结果表明，在圆形和方形立管的底部出现单个气泡，在矩形立管的底部出现双气泡。对于圆形和方形立管，电容信号的自相关是周期性的，对于矩形立管，电容信号的自相关是非周期性的。径向颗粒浓度分布在矩形和垂直立管中显示出单芯环形结构，而在长边上则为双芯环形结构，而在短立管中则为短边具有单芯环形结构。Shannon熵分析表明，对于矩形立管，流化的混乱程度较小，并且最容易预测。但在矩形立管中，沿长边的双芯环结构和沿短边的单芯环结构。Shannon熵分析表明，对于矩形立管，流化的混乱程度较小，并且最容易预测。但在矩形立管中，沿长边的双芯环结构和沿短边的单芯环结构。Shannon熵分析表明，对于矩形立管，流化的混乱程度较小，并且最容易预测。