Pulsed Micro-reactor: An alternative to estimating kinetic parameters of non-catalytic gas–solid reactions

Abstract

A Pulsed Micro-reactor (PMR) technique is demonstrated as a simple and viable alternative to generate kinetic data for non-catalytic gas–solid reactions. An experimental test rig was designed and fabricated for this purpose. Oxidation of Cu using air and reduction of CuO using methane, encountered in a novel form of combustion known as Unmixed Combustion (UMC), were chosen as representative reactions in this study. Plug flow conditions in the reactor, essential for accurate estimation of kinetic parameters, was confirmed using a Residence Time Distribution (RTD) approach. A simple generic methodology, based on a uniform reaction model is presented which allowed for easy interpretation of data from this reactor system. While the methodology has been validated for both reactions which were prima facie found to be surface reaction controlled, it can easily be extended to pore diffusion limited reactions. The estimated values of reaction orders and activation energies for both reactions and the pre-exponential factor for oxidation were found to be in excellent agreement with those obtained using Thermo Gravimetric Analysis (TGA). A lower value of pre-exponential factor for reduction however was obtained in the present investigation. While the PMR, can provide an initial insight into the reaction mechanism, it can also be used to obtain reaction engineering data related to process development.