Reaction Engineering for Microreactor Systems

Finite element simulations of two-and three-dimensional fluid flow, thermal fields, and chemical species concentrations in microfluidic devices are presented as a means for obtaining accurate predictions of microreactor performance. The chemical reaction engineering methodology is illustrated with case studies of a prototype microreactor for partial oxidation reactions. Platinum catalyzed ammonia oxidation serves as a demonstration chemistry. The reactor simulations are in excellent agreement with experimental observations. The results also mirror observed ignition-extinction behavior by revealing that ignition occurs downstream and the reaction front subsequently travels upstream due both to heat conduction and the presence of fresh reactants upstream. The utility of the simulation strategy in the design of microfluidic devices for chemical reactions is exemplified with a case study of placement of thermal shunts to control the shape of the reaction front.