Kinetics of Methyl Ethyl Ketone Combustion in Air at Low Concentrations over a Commercial Pt/Al2O3 Catalyst

Abstract

An investigation on the combustion in air of a common volatile organic compound, methyl ethyl ketone (MEK), over a commercial 0.5% Pt/Al2O3 catalyst has been performed. A tubular fixed-bed reactor operating both in the integral (ignition curves) and differential (kinetic study) modes was used at temperatures between 403 and 485 K, MEK partial pressures ranging from 12 to 191 Pa, and space times between 3160 and 25170 kgcat.·min·kmolMEK-1. Water and CO2 were the only reaction products. The apparent reaction orders for MEK given by an empirical power-law kinetic model decreased with reaction temperature from 0.75 at 478 K to 0.44 at 403 K. Several kinetic equations derived from mechanistic considerations have been investigated to account for this fact. The Mars−van Krevelen rate equation described well the kinetics of MEK combustion. However, it has been found that other rate equations derived from the Langmuir−Hinshelwood−Hougen−Watson formalism fit the kinetic data as well as or even better than the Mars−van Krevelen expression.