Drying characteristics of porous material in a fluidized bed of fluidizing particles with superheated steam
Drying characteristics of porous material in a fluidized bed of fluidizing particles with superheated steam
复制标题
过热蒸汽流化颗粒流化床中多孔材料的干燥特性
DOI：
10.1252/jcej.36.655
复制
发表时间：
2003
影响因子：
0.8
通讯作者：
N. Komatsu
中科院分区：
文献类型：
--
作者：
Y. Tatemoto;Y. Mawatari;Kazunori Sakurai;K. Noda;N. Komatsu
研究了多孔物料在过热蒸汽流化床中的干燥特性。气体扩散受努森扩散控制的B-1砖球用作干燥样品，玻璃珠（直径0.12 mm）用作流化颗粒。N2气也用作比较的干燥气体。N2气体是空气的替代品。分别改变流化床温度和干燥气质量流速。同时对样品中气体的对流传递和蒸汽在样品中的冷凝进行了理论分析，发现在过热蒸汽和热风流化床干燥中，样品中心温度都存在一个几乎恒定的阶段。过热蒸汽中试样中心温度高于热空气中试样中心温度。在过热蒸汽的情况下，在样品中心的温度几乎恒定的时间段期间的温度等于水的沸点。当样品中的传质阻力较大时，由于样品中的压力增加，样品中的温度升高。通过计算样品中的压力证实了这一现象。床层温度对干燥特性的影响较大，而干燥气的质量流速对干燥特性的影响很小。
The drying characteristics of porous materials immersed in the fluidized bed of fluidizing particles with superheated steam were examined. A B-1 brick ball, in which the gas diffusion was governed by Knudsen diffusion, was used as the drying sample and the glass beads (0.12 mm in diameter) were used as the fluidizing particles. N2 gas was also used as the drying gas for the comparison. N2 gas was the substitute of air. The temperature of the fluidized bed and the mass velocity of drying gas were changed, respectively. The theoretical analysis including the convective gas transfer in the sample and condensation of the steam in the sample was also preformed.There is a period when the temperature of the sample center is almost constant in the fluidized bed drying with superheated steam and with hot air. The temperature of the sample center in superheated steam is higher than that in hot air. In the case of superheated steam, the temperature during the period when the temperature of the sample center is almost constant is equal to the boiling point of water. When the mass transfer resistance in a sample is large, the temperature in the sample increases because of the increment of the pressure in the sample. This phenomenon was confirmed by the calculated pressure in the sample. The effect of the bed temperature on the drying characteristics is significant, while that of the mass velocity of drying gas is very slight.