Experimental and Numerical Investigation of a Propane-Fueled, Catalytic, Mesoscale Combustor

Abstract

The present work undertakes a combined experimental and numerical investigation of a propane-fueled, platinum-coated, mesoscale combustor, which is candidate for portable power generation applications. As a first step, the heterogeneous reactivity of propane on platinum has been assessed with gas-phase Raman spectroscopy and an appropriate global reaction step for lean propane/air combustion was constructed, valid at pressures 1 ≤ p ≤ 7 bar, a range of interest to microreactors and small-scale industrial turbines. In a second step, a detailed numerical parametric study in a single catalytic channel has been performed, with inlet conditions and combustor material properties as the parameters of main interest, aimed at defining regimes of optimal power output and fuel conversion. Detailed numerical treatment was provided for the heat transfer mechanisms inside the channel, which included heat conduction in the solid and surface radiation heat exchange between the reactor elements themselves and between the reactor and its surroundings. Based on the findings of the aforementioned parametric study, the third and final step involved the construction and testing of a mesoscale catalytic combustor for a range of operational parameters relevant to micro- and mesoscale power generation applications. A continuum model for the entire combustor monolith was developed to complement the experiments, thus allowing for the simulation of the temperature 2-D distribution inside the combustor. This numerical tool facilitated the detailed modeling of the heat losses from the catalytic combustor, evident in the experiments, and allowed for further design improvements.