Modeling Tools for Environmental Engineers and Scientists

\5.2.2 HETEROGENEOUS REACTORSHeterogeneous reactors entail reactions within two or more differentphases such as gas-liquid, gas-solid, and liquid-solid systems. Classificationof heterogeneous reactors commonly used in environmental studies is shownin Table 5.2.While transport at the macro and reactor scales and reaction rates arethe significant factors in homogeneous systems, micro- and macro-transportscales and inter- and intraphase mass transfer processes are significant inheterogeneous systems. As such, hydraulic retention times and reaction rateconstants characterize homogeneous systems, and reaction rates and masstransfer coefficients characterize heterogeneous systems. The amounts ofinterfacial surface areas and path lengths for intraphase transport as well asbulk fluid dynamics contribute to the effectiveness of various heterogeneousreactor configurations.5.3 MODELING OF HOMOGENEOUS REACTORSIn the following sections, development of the MB equation for variousconfigurations of homogeneous reactors is summarized. The goal of this sectionis not to provide a formal treatment of reactor engineering, but instead toillustrate the different forms of MB equations, mathematical formulations,and the solution procedures that are involved in the modeling of commonengineered environmental reactors.Table 5.2 Classification of Heterogeneous Reactors© 2002 by CRC Press LLC