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Combust. Sci. and Tech.,
1991. Vol. 79, pp. 97-128
Photocopying permitted by license only
© Gordon and Breach Science Publishers S.A.
Printed in United Kingdom
A Comprehensive Reaction Mechanism For Carbon
R. A. YETTER and F. L. DRYER
Department of Mechanical and Aerospace
Engineering. Princeton Universitv, Princeton. NJ 08544
and H. RABITZ
Department of Chemistry, Princeton University. Princeton.
(Received October 17, 1990; in final form March 12, 1991)
Abstract-A comprehensive reaction mechanism for the oxidation ofcarbon monoxide in the presence of
hydrogen is described. Model
predictions are compared with experimental data over wide ranges of
physical conditions. The data. obtained from shock
tube experiments and
various types of reactor
experiments, encompassed a combined temperature range of 823-2870 K, fuel-oxidizer equivalence ratios
between 0.0005 and 6.0. C/H ratios between 0.005 and: 28, and pressures between 0.3 and 2.2 atmospheres.
Validation of the reaction mechanism is obtained with reproduction of the experimental results by the
model predictions and from sensitivity analysis calculations. Results from the latter calculations provided
a quantitative measure of the sensitivity of the model predictions to the imposed input parameters over the
complete range of experimental parameters noted above.
reaction mechanisms. CO/H
oxidation, modelling, sensitivity analysis.
A comprehensive reaction mechanism is a set of reactions which has been tested and
validated against experimental data over a wide range of physical conditions. The
purpose of a comprehensive mechanism is to have a generalized reaction mechanism
which can reproduce
modification all of the available experimental data and
furthermore predict, with some degree of confidence, the kinetic behavior of systems
for which experimental data are not available. This latter condition is generally valid
when the kinetics to be predicted fall within the boundaries for which the mechanism
has been validated. Outside this region of calibration, predictions from comprehen-
sive mechanisms should be used cautiously.
In the present paper, a comprehensive reaction mechanism for moist CO oxidation
is reported. The mechanism for the carbon monoxide/hydrogen/oxygen system, like
the hydrogen/oxygen system, is an integral part of all hydrocarbon mechanisms. In
the hierarchical structure ofcomplex hydrocarbons, it is a fundamental sub-mechan-
ism falling between the simpler H,/O, system and the more complex formaldehyde
The carbon monoxide/hydrogen/oxygen system has been reviewed in detail by
Dixon-Lewis and Williams (1977) through the 1975literature, by Gardiner and Olson
(1980) through 1979, and subsequently by Westbrook and Dryer (1984). The general
conclusions of these reviews are that most of the important elementary reactions and
chemical species have been identified and that the rates ofmost reactions are reason-
ably well known over an extended temperature range. However, past modeling studies