(521ca) Designing a Concentration-Modulated Microreactor with Integrated Activity Analysis for Dynamic Catalytic Partial Oxidation of Methane

The next-generation distributed reactor concept relaxes assumptions conventionally applied to large scale reactors – namely steady state, isothermal reactor operation. In this work, we consider the design requirements needed to achieve 10-millisecond gas phase switching of a catalytic reaction system, thus allowing us to access a dynamic operating regime on the timescale of the surface kinetics. We then use residence time distributions and pressure drop measurements to characterize the square wave transient achieved in the capillary microreactors used in this study. Residence time distributions were found to be sensitive to delays in trigger time logging, requiring short response time for gas injection, high sampling frequency for gas concentration and averaging to obtain mean residence time and Peclet number from the open-open boundary dispersion model. The results revealed near plug flow and 10 millisecond residence times at pressures as low as 6 psig. Feed modulation achieved square waveforms at frequencies up to 25 Hz, with a maximum operating frequency of 50 Hz. The reactor is integrated in a gas chromatograph, providing fast MS/FID for analysis of products and temperature programmed oxidation to measure catalyst activity, selectivity, and coking.