Application of an extended shrinking film model to limestone dissolution

The reactions of soluble and reactive solids with components in the liquid phase are of high relevance in the field of chemical engineering. A mathematical model was recently developed applying an extended film theory, where the reactive solid material dissolves in the liquid phase and diffuses through a dynamic liquid film surrounding the particle. In the present work, this Extended Shrinking Film Model (E.S.F.M.) was applied to a very challenging reaction, the limestone dissolution in an acid environment. The model was applied to experimental data collected under a wide range of operation conditions, i.e., varying temperature, particle size, stirring rate, and type of limestone. A very good fit of the model to experimental data was obtained, and the chemical and physical phenomena were clearly identified, significantly contributing to understanding of the reaction kinetics. The work clearly demonstrates that the data interpretation can be considerably enhanced by rigorously taking into account the physical phenomena and that E.S.F.M. can be used in planning larger reactors, due to its flexibility in predicting the reaction kinetics at different conditions.