A detailed chemical kinetic model for high temperature ethanol oxidation

A detailed chemical kinetic model for ethanol oxidation has been developed and validated against a variety of experimental data sets. Laminar flame speed data (obtained from a constant volume bomb and counterflow twin-flame), ignition delay data behind a reflected shock wave, and ethanol oxidation product profiles from a jet-stirred and turbulent flow reactor were used in this computational study. Good agreement was found in modeling of the data sets obtained from the five different experimental systems. The computational results show that high temperature ethanol oxidation exhibits strong sensitivity to the fall-off kinetics of ethanol decomposition, branching ratio selection for C2H5OH + OH ↔ Products, and reactions involving the hydroperoxyl (HO2) radical. The multichanneled ethanol decomposition process is analyzed by RRKM/Master Equation theory, and the results are compared with those obtained from earlier studies. The ten-parameter Troe form is used to define the C2H5OH(+M) ↔ CH3 + CH2OH(+M) rate expression as k∞ = 5.94E23 T−1.68 exp(−45880 K/T) (s−1) ko = 2.88E85 T−18.9 exp(−55317 K/T) (cm3/mol/sec) Fcent = 0.5 exp(−T/200 K) + 0.5 exp(−T/890 K) + exp(−4600 K/T) and the C2H5OH(+M) ↔ C2H4 + H2O(+M) rate expression as k∞ = 2.79E13 T0.09 exp(−33284 K/T) (s−1) ko = 2.57E83 T−18.85 exp(−43509 K/T) (cm3/mol/sec) F cent = 0.3 exp(−T/350 K) + 0.7 exp(−T/800 K) + exp(−3800 K/T) with an applied energy transfer per collision value of = 500 cm−1. An empirical branching ratio estimation procedure is presented which determines the temperature dependent branching ratios of the three distinct sites of hydrogen abstraction from ethanol. The calculated branching ratios for C2H5OH + OH, C2H5OH + O, C2H5OH + H, and C2H5OH + CH3 are compared to experimental data. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 183–220, 1999