A New Design of Reverse-Flow Reactors with Enhanced Thermal Dispersion

Recent research has demonstrated the superiority of reverse-flow catalytic oxidation reactors for the combustion of volatile organic compounds in gaseous industrial effluents, yet widespread industrial use is limited because of its tendency toward thermal runaway. In this paper, runaway is alleviated through a proposed basic redesign of the reactor, where metal rods or pins are imbedded in an optimal configuration within the packed bed. Although the rods only occupy 10% of the bed volume, their presence induces a transient Taylor−Aris thermal diffusivity which is orders of magnitude larger than that of the original bed, and effectively stabilizes the bed against hot spot formation. Analytical design correlations are derived for the optimal insert spacing and reversal time for arbitrary reactions and flow conditions using asymptotic expansion and scaling theories.