Process simulation of gas-to-particle-synthesis via population balances:: Investigation of three models

The simulation of complex gas-phase reactors for the synthesis of fine particles requires the coupling of particle and fluid dynamics. A previously developed CFD-coupled simulation technique based on a monodisperse population balance model is an efficient tool but seriously restricted when the product's polydispersity is of interest. Therefore, two other sectional population balance models have been developed: an extended 1-dimensional model and a simplified 2-dimensional model. Comparing calculations were performed with all three models, and temperature, concentration and sintering time were chosen as varying parameters. Using the 2-dimensional model as a benchmark, the conformity with the 1-dimensional sectional model is excellent for all cases investigated. Hence, due to the enormous difference in computational effort and time, clear preference can be given to the simpler sectional model. With respect to the monodisperse model, quite satisfactory results are found deviating mainly because of the typical, slower coagulation behavior of monodisperse particle systems. As a CFD-coupled technique only the 1-dimensional model is considered as an alternative to the simple monodisperse model as the computational demand of the 2-dimensional model is extremely high. A simple test simulation proves that the 1-dimensional model coupled with a commercial CFD software is a generally feasible technique. However, the computational time required is tremendous and impedes the present application. (C) 2002 Elsevier Science Ltd. All rights reserved.