MODELING OF EVACUATED PULSE MICRO-REACTORS

The system for temporal analysis of products consists of a micro-react or, a high-speed gas pulsing valve, and a computer-controlled real-tim e quadrupole mass spectrometer. A pulse of reactant is introduced at t he entrance of the micro-reactor and evacuated through the catalyst be d creating a mass spectrometer response. Quantification of kinetic par ameters from such measurements requires a well-defined flow mechanism in the micro-reactor and an appropriate model of the system. Experimen tal methods for establishing Knudsen flow in the catalyst bed are outl ined. The governing differential equation for the packed-bed micro-rea ctor is established, and the suitability of various boundary condition s is discussed. The effect of the inlet section on the response is ill ustrated and quantified. A simple boundary condition of zero exit conc entration is justified. The developed model provides the foundation fo r quantification of results obtained in transient response experimenta l systems that utilize evacuated packed-bed micro-reactors.