Tutorials Manual

Chapter 2: Combustion in Gas-phase Processes
Tutorials Manual
2.8.3 NOx and CH 4 , C 2 H 4 , C 2 H 6 , C 3 H 6 , and C 3 H 8
This reaction mechanism is made available by Lawrence-Livermore National Labs.
The gas-phase kinetics input file contains 5 elements, Ar, C, H, O, and N, 126
chemical species, and 638 reversible reactions. The chemical kinetic mechanism was
validated to describe the promotion effect of hydrocarbons (methane, ethane, ethene,
propene and propane) on NO to NO 2 conversion in an atmospheric flow reactor. The
NO level was 20 ppm and the hydrocarbon level was 50 ppm. The flow reactor
temperature ranged from 600 to 1100 K.
2.8.4 Propane/Air
This mechanism is the result of work at the Center for Energy Research (CER),
University of California, San Diego. It consists of 46 species and 235 reactions. The
elements constituting the species are N, H, C, O, Ar, and He. The thermodynamic and
transport data in this chemistry set are included from the same source. All reactions
are reversible, and some of the reactions include pressure-dependencies on the rate
constant using the Troe formulation (see Equation 3-27 in the CHEMKIN Theory
Manual). Enhanced collision efficiencies are used for some reactions. The references
for the reaction rate parameters as well as for thermodynamic and transport data can
be obtained from the CER website:
http://maemail.ucsd.edu/combustion/cermech/
2.8.5 Ethylene/Air Combustion and Soot Formation and Growth
2.8.5.1 Combustion Mechanism and Soot Nucleation Reaction
The C 2 H 4 -air combustion mechanism of Appel et al. 25 is used in the simulation. This
reaction mechanism consists of 101 species and 543 reactions which include PAH
growth reactions up to pyrene, A4.
According to Frenklach and coworkers 25,26 , soot particles are created by the
dimerization of pyrene molecules. However, the Particle Tracking Module does allow
multiple inception paths as suggested by Marr 23 (see p. 78) . The kinetic parameters of
the soot nucleation reaction are derived by matching the nucleation-only soot mass
concentration prediction at PFR inlet to the measurement.
(S1) 2A4=>32C(B)+20H(S)+28.72(S) 2.00E08 0.5 0.0
25. J. Appel, H. Bockhorn, and M. Frenklach, Combust. and Flame, 121:122-136 (2000).
26. M. Frenklach and H. Wang, in Soot Formation in Combustion: Mechanisms and Models,
H. Bockhorn (Ed.), Springer-Verlag, pp. 165-192 (1994).
RD0411-C20-000-001 87 © 2007 Reaction Design