Combustion kinetics of cyclooctane and its binary mixture with o-xylene over a Pt/γ-alumina catalyst

Abstract

Combustion kinetics of the cyclooctane and o-xylene, alone and in their binary mixture, have been experimentally investigated over a commercial Pt/γ-alumina catalyst. The studies were carried out in a laboratory set-up, with diluted hydrocarbon-air mixtures, typical for depollution applications. The experiments were conducted at atmospheric pressure and temperatures between 140 and 400°C, hydrocarbons concentration 200–1000ppmv and WHSW (mass flow rate to catalyst weight ratios) in the range 280–590h−1. The results evidenced an important inhibition of cyclooctane combustion by the presence of o-xylene, throughout the working domain. Based on the experimental measurements and postulating surface mechanisms, rate expressions were developed for the combustion of the two hydrocarbons, in pure state and as binary mixtures. The cyclooctane was found to react by an Eley–Rideal type mechanism, whereas the o-xylene combustion was explained by a Langmuir-Hinshelwood scheme.