Coupled Catalytic/Gas Phase Ignition of Propane-Oxygen-Inert Mixtures on an Isothermally Heated Platinum Filament Supported on Quartz Bar

Abstract

The ignition of gaseous flammable mixtures on catalytically active hot solid surfaces is an intricate process implying the tight interaction between surface and gas phase reactions. The paper presents the results obtained from the study of coupled catalytic-gas phase ignition of propane-oxygen-inert mixtures on an isothermally heated platinum filament stabilized on a thin quartz bar, measuring the induction periods, ti, rates of heat release, (dQr/dt)t and minimum ignition energies, Qmin. The experiments were conducted at different initial pressures between 73 and 101 kPa and filament temperatures between 1080 and 1184 K for 2.68% propane-air mixture and 4.02% propane-air mixture diluted with Ar or N2 in ratio 2:1. For any total pressure, the fuel concentration is the same in each mixture, the complementary composition containing the necessary oxygen for complete combustion and inerts or/and excess oxygen. The measured properties were rationalized using Arrhenius-type kinetic equations.