A framework for modeling particle size effects in emulsion polymerization systems using computational fluid dynamics linked to a detailed population balance model Rebecca C. Elgebrandt a , David F. Fletcher a , Vincent G. Gomes a , Jose A. Romagnoli a,b a Department of Chemical Engineering, The University of Sydney, NSW 2006, Australia b Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803 Abstract To improve modeling of emulsion polymerization systems at a reasonable computational cost, a hybrid-multizonal framework is being developed using the process simulation software gPROMS and the computational fluid dynamics (CFD) package FLUENT. The use of a detailed kinetic model in conjunction with CFD enables the incorporation of information about a number of additional phenomena that might affect the PSD, into the kinetic model. One phenomenon in particular is the shear dependence of coagulation which can now be treated in much greater detail. Additionally, information from the kinetic model, such as changes in the viscosity of the latex due to the evolution of the PSD that may affect the flow field is also passed to the CFD package. The details of the framework is presented, as is a preliminary study on the effect of the exchange flows between the zones and the effect of the shear rates on the PSD. Keywords: emulsion polymerization, hybrid-multizonal model, CFD, process simulation 1. Introduction Modeling and simulation of emulsion polymerisation is a challenging task because of the complex physico-chemical sub-processes existing within the multiphase process. The particle size distribution (PSD) is of major importance to product characteristics and a number of kinetic models have been developed in order to predict its evolution. These kinetic models assume perfect mixing within the reactor. However, in reality this is not valid, as the flow field in the reactor also plays an important role in the evolution of the PSD. Not only does it affect reactor homogeneity, it also plays an important part in reactor heat transfer and controls the coagulation behaviour. Additionally, the flow field alters the dynamic viscosity of latex in an emulsion polymerization reaction because of the non-Newtonian rheology. This effect is particularly strong for latices with high solid content. The effect of the kinetics, as well as the flow field, on the PSD in emulsion polymerization is thus of major interest to the polymer industry. While extensive models of either of the two processes are readily available, combined models are still in their infancy. and 9th International Symposium on Process Systems Engineering W. Marquardt, C. Pantelides (Editors) © 2006 Published by Elsevier B.V. 16th European Symposium on Computer Aided Process Engineering 551