采用自主研发的狭缝型分布板流化床,对Geldart D 类颗粒物料核桃壳（2～2.8mm）的流化特性进行了实验研究.结果表明：与传统多孔型分布板相比,空床时狭缝型分布板的分布板压力降较小,加入物料时狭缝型分布板的床层压力降大,更多的能量...采用自主研发的狭缝型分布板流化床,对Geldart D 类颗粒物料核桃壳（2～2.8mm）的流化特性进行了实验研究.结果表明：与传统多孔型分布板相比,空床时狭缝型分布板的分布板压力降较小,加入物料时狭缝型分布板的床层压力降大,更多的能量用于物料的流化,特殊的瓦楞结构也可改善物料的流化特性;Geldart D 类颗粒物料在狭缝型分布板流化床内流化效果较好,相应的床层膨胀比也较大.展开更多
Hydrodynamic characteristics of fluidization in a conical or tapered bed differ from those in a columnar bed because the superficial velocity in the bed varies in the axial direction. Fixed and fluidized regions could...Hydrodynamic characteristics of fluidization in a conical or tapered bed differ from those in a columnar bed because the superficial velocity in the bed varies in the axial direction. Fixed and fluidized regions could coexist and sharp variations in pressure drop could occur, thereby giving rise to a noticeable pressure drop-flow rate hysteresis loop under incipient fluidization conditions. To explore these unique properties, several experiments were carried out using homogeneous, well-mixed, ternary mixtures with three dif- ferent particle sizes at varying composition in gas-solid conical fluidized beds with varying cone angles. The hydrodynamic characteristics determined include the minimum fluidization velocity, bed fluctuation, and bed expansion ratios. The dependence of these quantities on average particle diameter, mass fraction of the fines in the mixture, initial static bed height, and cone angle is discussed. Based on dimensional analysis and factorial design, correlations are developed using the system parameters, i.e. geometry of the bed （cone angle）, particle diameter, initial static bed height, density of the solid, and superficial velocity of the fluidizing medium. Experimental values of minimum fluidization velocity, bed fluctuation, and bed expansion ratios were found to agree well with the developed correlations.展开更多
文摘采用自主研发的狭缝型分布板流化床,对Geldart D 类颗粒物料核桃壳（2～2.8mm）的流化特性进行了实验研究.结果表明：与传统多孔型分布板相比,空床时狭缝型分布板的分布板压力降较小,加入物料时狭缝型分布板的床层压力降大,更多的能量用于物料的流化,特殊的瓦楞结构也可改善物料的流化特性;Geldart D 类颗粒物料在狭缝型分布板流化床内流化效果较好,相应的床层膨胀比也较大.
文摘Hydrodynamic characteristics of fluidization in a conical or tapered bed differ from those in a columnar bed because the superficial velocity in the bed varies in the axial direction. Fixed and fluidized regions could coexist and sharp variations in pressure drop could occur, thereby giving rise to a noticeable pressure drop-flow rate hysteresis loop under incipient fluidization conditions. To explore these unique properties, several experiments were carried out using homogeneous, well-mixed, ternary mixtures with three dif- ferent particle sizes at varying composition in gas-solid conical fluidized beds with varying cone angles. The hydrodynamic characteristics determined include the minimum fluidization velocity, bed fluctuation, and bed expansion ratios. The dependence of these quantities on average particle diameter, mass fraction of the fines in the mixture, initial static bed height, and cone angle is discussed. Based on dimensional analysis and factorial design, correlations are developed using the system parameters, i.e. geometry of the bed （cone angle）, particle diameter, initial static bed height, density of the solid, and superficial velocity of the fluidizing medium. Experimental values of minimum fluidization velocity, bed fluctuation, and bed expansion ratios were found to agree well with the developed correlations.
