Modeling of Semibatch Agglomerative Gas−Liquid Precipitation of CaCO3 in a Bubble Column Reactor

Abstract

The outcome of gas−liquid precipitation in industrial reactors, such as bubble columns, is determined by the interplay between multiphase fluid dynamics; gas−liquid reaction engineering; and crystallization mechanisms such as nucleation, growth, and agglomeration. In this work, a modeling approach that takes the above phenomena into account is proposed and applied to investigate the semibatch precipitation of CaCO3. The main elements of the approach are a dynamic population balance equation including nucleation, growth, and agglomeration, discretized with a finite element method; a phenomenological model of interfacial mass transfer and reaction based on penetration theory; and rigorous prediction of gas holdup via an Eulerian−Eulerian multiphase CFD code. Experiments on CaCO3 precipitation via reaction of CO2 and Ca(OH)2 in a 21-L bubble column are conducted and simulated with the aid of the model. The evolution of the process is adequately reproduced, and qualitative comparisons with the product CSD are...