Ignition of Premixed Methanol/Air in a Heated Flow Tube and the Effect of NO₂ Addition

Abstract

Abstract-The wall temperature at which a premixed methanol/air mixture ignited was determined as a certain measure of ignition delay in a quartz tube around 1000 K as a function of equivalence ratio under several different flow velocities. The kinetic model of methanol combustion proposed by Westbrook and Dryer (1979) was successfully applied for analysing the ignition process. When a small amount of NO₂ was added, the temperature decreased appreciably; this was analysed in terms of the above combustion model combined with a series of reactions initiated by the hydrogen atom abstraction from methanol by NO₂: CH₃OH + NO₂→CH₂OH + HNO₂. The corresponding rate constant was determined as 10^11.3±0.3 exp[-22.6(kcaI.mol^-1)/RT] cm3 mol^-1 s^-1 in the temperature range of 900-1100 K.