High conversion hydrogen peroxide microchannel reactors: Design and two-phase flow instability investigation

Abstract

Novel micro-scale reaction devices are progressing in various applications. Whereas, specialized gas-producing reactors of high conversion at micro/mini scale remain challenging and are rarely explored, but are needed urgently in new generation vehicles and aerospace applications. In this work, two kinds of high-aspect-ratio flat channel (200 μm depth, 5.0 mm width, and 40.0 mm length) microreactors with platinum foil catalyst, named as inlet reactors and outlet reactors, are designed and tested for H2O2 decomposition. The wavelet transform method is applied to analyze the effects of reactant flow rate and pin–fin configuration on flow instability in both the time domain and the frequency domain. The inlet reactors utilize periodic flow pattern transitions to achieve an independence of conversion on reactant flow rate. For outlet reactors, the upstream compressible slug volume and the backflow are restricted by the pin–fin array, and thus the H2O2 decomposition reaches a conversion of 59.0% at 5 ml/h reactant flow rate. This conversion is 300% higher than those of H2O2 decomposition in microchannel reactors ever reported in the literature. The results from this work can be used for the design and manufacturing of micro-scale reactors for gas involved applications.