Experiemental Studies of Intra-Particle Forced Convection in Large-Pore Materials

大孔材料在催化、色谱、陶瓷膜、吸附和固定化细胞发酵等化学工程领域有着广泛的应用。在每种情况下，材料的有效性都被认为是通过粒子内强制对流来增强的，这改善了粒子内的传质。一些研究人员提出了这种现象的模型，旨在提供预测这些材料在各种操作条件下性能的方法。然而，所有的模型都依赖于粒子内速度的理论估计来确定传质速率，而没有提供实验证实。本项目旨在利用一种独特的颗粒流装置来测量颗粒内速度与压降的关系。对结果的分析将提供粒子达西常数的定量测量。该常数可用于任何压力梯度场，包括填料床和流化床，以确定相应的颗粒内流体流场。这个领域的知识将允许发展一个更全面的粒子内传质模型，包括扩散和对流。该模型应适用于使用大孔隙材料的任何类型的工艺，因此可用于确定其最佳操作条件。＊＊＊

9311457 Hsu Large-pore materials have been used in many chemical engineering applications such as catalysis, chromatography, ceramic membranes, adsorption and immobilized cell fermentation. In each case, the effectiveness of the material is believed to be enhanced by intraparticle forced convection which improves the intraparticle mass transfer. Several investigators have presented models of this phenomenon which are intended to provide methods of predicting the performance of these materials under various operating conditions. However, all of the models rely on theoretical estimates of the intraparticle velocity in determining the mass transfer rates without providing experimental confirmation. This project seeks to measure the intraparticle velocity versus pressure drop relationship using a unique particle flow apparatus. Analysis of the results will provide a quantitative measure of Darcy's constant for the particle. This constant can then be used in any pressure gradient field, including packed and fluidized beds, to determine the corresponding intraparticle fluid flow field. Knowledge of this field will allow for the development of a more comprehensive model of intraparticle mass transfer which includes both diffusion and convection. Such a model should be applicable to any type of process which uses the large-pore materials and therefore can be used to determine their optimum operating conditions. ***