Shock tube study on homogeneous thermal oxidation of methanol

Abstract

Homogeneous thermal oxidation of methanoloxygen mixtures, highly diluted with argon, was studied in shock waves by following infrared emission of various species during the course of the reaction. The equivalence ratio φ = 1.5 [CH 3OH] [O 2] was varied from 0.2 to 2.0. The total density extended from 1 × 10 −5 to 2 × 10 −4 mol/cm 3. For mixtures of methanol and oxygen between 0.05 and 1.0%, the following expression describes the induction period: r i = 1.4 × 10 −16 [ CH 3>OH ] −0.1[ O 2] −O.19[ Ar] −O.62 X exp (201 kJ/mol/RT) s. For very dilute mixtures, the experiments indicated a decrease of the power dependency of argon density. In order to obtain the mechanism for the oxidation of methanol, profiles of some species were obtained from the numerical integration of 57 reactions and were compared with the measured results. The calculated induction periods agreed well with the measured ones. The argon density strongly influences the induction period in the mixtures with less than 1% CH 3OH since the decomposition of H 2O 2 plays an important role during the induction period.