Multi-scale modeling of a mixing-precipitation process in a semibatch stirred tank

In this work the influence of turbulent mixing on the course of barium sulfate precipitation is investigated for a process carried out in a semibatch stirred tank reactor. A time-scale analysis for the controlling process mechanisms is presented to highlight the multi-scale nature of the process. A detailed CFD based process model is presented which accounts for all relevant phenomena from the micro- to the macro-scale and interactions between mechanisms on different scales. Computational results of the models for various operating conditions, i.e., different agitation rates, reactant concentrations and feed addition modes, are compared with experimental data and simulation results obtained using a simpler mechanistic model, thus highlighting the strengths of the complex model. (c) 2007 Elsevier Ltd. All rights reserved.