The shape of solids undergoing a reaction with a fluid influences how the reaction proceeds with conversion. Complex numerical solutions are needed in general to calculate the conversion–time relation for reactions involving nonbasic solids. This paper presents two simplified, although approximate, methods for obtaining conversion–time relations for such solids. In the shape-factor method, a shape factor is determined for a nonporous solid of the same shape reacting under interfacial reaction control and this shape factor is used to predict the conversion–time relation under pore-diffusion control. In the Sohn–Wall method, the progress of the reaction front under pore-diffusion control is simplified so that a closed-form equation approximately describing its position, and thus the conversion, may be found. Good agreement was observed between the exact numerical solution of nonbasic solids and these two approximate methods. Either of these methods can be combined with Sohn’s law of fluid–solid reactions to describe the overall conversion–time relationship of a fluid–solid reaction under a simultaneous rate control by chemical reaction and pore diffusion.

中文翻译：

---

非基本几何形状的固体的流固反应动力学：Sohn-Wall方法与形状因子方法的比较

与流体进行反应的固体的形状影响反应如何进行转化。通常需要复杂的数值解来计算涉及非基本固体的反应的转化时间关系。本文介绍了两种简化但近似的方法来获得此类固体的转化时间关系。在形状因子方法中，确定了在界面反应控制下反应的相同形状的无孔固体的形状因子，该形状因子用于预测在孔扩散控制下的转化时间关系。在Sohn-Wall方法中，简化了在孔扩散控制下反应前沿的进展，以便可以找到近似描述其位置并由此转化的闭合形式方程。非基本固体的精确数值解与这两种近似方法之间观察到很好的一致性。这些方法中的任何一种都可以与Sohn固-固反应定律结合起来，以描述在化学反应和孔扩散同时进行速率控制下，固-固反应的总转化时间关系。