Millisecond reaction processes utilizing catalytic monoliths provide high throughput and commercially interesting conversions for important basic chemical production such as synthesis gas production, ethane oxidative dehydrogenation and HCN synthesis. Although these reactors exhibit high productivity per reactor volume, safe mixing and preheating of the hydrocarbon and the oxygen and delivery to the catalytic monolith are still serious concerns. Prior efforts focused on distributing the safety risk by using several small mixing elements. This approach however diminishes capital cost reduction, which is the main economic advantage of millisecond reaction processes. Praxair has developed a new method for mixing and preheating hydrocarbon/oxygen mixtures. The basis for this novel reactor design is a unique system that can produce a high temperature (1600C) and high velocity (Mach >1) oxygen stream. This oxygen stream is rapidly mixed with the hydrocarbon in a mixing chamber and then the reaction mixture is delivered to the catalyst before the onset of any significant homogeneous reaction. The main advantage of this design is that the oxygen temperature and velocity are regulated with great precision, and are used to enhance mixing with natural gas. In collaboration with U. Delaware and Foster Wheeler and with the support of National Energy Technology Laboratory, Praxair has completed a development program that included reactor experiments with natural gas and O2 at pressures up to 20 atm, detailed kinetic simulations and process analysis for using this reactor as a basis for a gas to liquid (GTL) plant. Results of this program with emphasis on reactor design and process economics will be presented.

This paper was prepared with the support of the U.S. Department of Energy, under Award No. DE-FC26-00NT41027. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE