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先后在高10 m,提升管截面分别为边长0.27 m方形和内径0.187 m圆形的冷态循环流化床实验台上开展针对B类石英砂颗粒的实验,研究提升管结构及操作条件对床内流动特性的影响,并分析实现高密度循环流动的条件。圆床中固体循环流量Gs超过300 kg/(m2s),实现了高密度循环;方床中由于装置结构因素,影响了Gs的提高。与A类颗粒不同,对于实验采用的B类颗粒,固体循环流率超过饱和循环流率时,轴向固体颗粒浓度依然呈现指数型分布,未出现S型分布。实验操作条件下,圆床和方床中提升管总压降均与固气比成线性关系,但线性斜率差别明显。通过无量纲提升管高径比关联固气比和提升管总压降,正确反映了提升管结构对流动的影响,通过实验值的比较,采用高径比关联后,固气比与不同结构下提升管总压降的线性关系较一致。
Successively in the height of 10 m, riser cross-section of 0.27 m for the side of the square and the inner diameter of 0.187 m round cold circulating fluidized bed test bed for Class B quartz sand particles experiments to study the riser structure and operating conditions of Bed flow characteristics of the impact and analysis of high-density circulating flow conditions. In the round bed, the solid circulating flow rate Gs exceeded 300 kg / (m2s), realizing a high density circulation. The square bed affected the improvement of Gs due to the structural factors of the unit. Different from the type A particles, for the type B particles used in the experiment, when the circulating flow rate of the solid exceeds the saturated circulating flow rate, the axial solid particle concentration still shows an exponential type distribution, and no S type distribution occurs. Under the experimental operating conditions, the total pressure drop of the riser in the round bed and the cot has a linear relationship with the solid-gas ratio, but the linear slope is obviously different. Through the dimensionless riser VSWR and the total pressure drop in the riser, the influence of the riser structure on the flow is correctly reflected. Through the comparison of the experimental values and the correlation of the height-diameter ratio, The linear relationship between the total tube pressure drop is more consistent.