Development of a Mini-Channel Heat Exchanger Reactor with Arborescent Structures for Fast Exothermic Reactions

Abstract

Uniform flow distribution, efficient mixing of reactants, and rapid removal of reaction heat are very crucial to ensure a safe operation and high product yield for fast and highly exothermic reactions. In this study, a plate-type mini-channel heat exchanger reactor with arborescent structures (AR reactor) was developed. A numerical simulation is first performed to investigate the effects of the arborescent structures and configurations of heat exchange channels on the fluid flow and heat transfer characteristics. The simulation results show that the arborescent structure with smoothed junctions presents better heat transfer performance with a lower pressure drop than the original one with a rectangular cross-section, and more uniform flow rates and temperature distributions can be achieved when the parallel flow channels of the heat exchange plates are arranged based on the uniform flow resistance by adding two micropillars. A better AR reactor based on the simulation results was then fabricated, and its overall heat transfer coefficient was measured experimentally, which is in good agreement with the simulation data. The AR reactor is further utilized to conduct the nitration of phenol, and it is demonstrated that this reactor endows more aim product in a very short time in comparison with the traditional reactor. The insights gained here could provide a new avenue for the design of microchannel heat exchange reactors suitable for fast exothermic reactions.