Multi-scale modeling of microstructured reactors for the oxidative dehydrogenation of ethane to ethylene

A novel ethylene production process has been developed via oxidative dehydrogenation of ethane in microstructured reactors. This process, where hydrogen is combusted in close contact with the endothermic dehydrogenation reaction, has the potential to significantly improve the economics of ethylene production. The oxidative dehydrogenation reactor walls are coated with a novel catalyst that enables both high activity and high selectivity to ethylene. Overall reactor performance has exceeded 75% ethane conversion and 84% ethylene selectivity without performance degradation over several 100 h in laboratory experiments. The reactor operated with a peak temperature near 950 degrees C and a reaction contact time less than 50 ms. Single pass ethylene yield far exceeded that possible in a conventional stream cracker. Reactor design was enabled by the use of computational flow dynamic (CFD) models at three levels: local, intermediate and global. A local model reduced the set of kinetic equations to a manageable few. An intermediate model assessed the reactor performance in a single channel with a simplified set of kinetics. A global model set the required performance parameters, including flowrate per reactor volume, conversion and selectivity for practical, commercial implementation in a reactor with thousands of parallel microchannels. (C) 2007 Elsevier B.V. All rights reserved.