Experimental and numerical investigation of a propane-fueled, catalytic mesoscale combustor

Abstract

Small-scale thermochemical devices driven by hydrocarbon-fueled combustors have attracted increased attention for portable power generation applications due to their superior power density compared to state of the art Li-ion batteries. A combined experimental and numerical investigation is presented for the performance characteristics of a mesoscale, propane-fueled, catalytic combustor, to be used in an integrated, gas-turbine-based, mesoscale (ca. 100 W el) power generation system. Experiments in an optically accessible reactor led to a global reaction rate for the total oxidation of propane on platinum, valid over the pressure range 1 bar ≤ p ≤ 7 bar. Parametric numerical studies were subsequently carried out in a single catalytic channel, using a 2D elliptic code with the aforementioned validated kinetic scheme and all relevant heat transfer mechanisms. The predictions identified favorable materials and operating conditions for the burner under consideration. A subscale monolithic honeycomb reactor was finally constructed, based on the findings of the parametric study. The reactor met the set goals for power output as a function of mass throughput. However, heat losses to the environment were responsible for measuring reduced combustor efficiency at certain operating conditions. A continuum model for the entire monolithic structure complemented the experiments and provided the 2D temperature field. Computed exhaust gas temperatures of the monolith were in good agreement with the measurements.