Vandooren, J., de Guertechin, L.O., and Van Tiggelen, P.J. (1986)
Kinetics in a Lean Formaldehyde Flame
Combust. Flame 1986, 64, 127.
Abstract
The structure of a lean formaldehyde-oxygen flame burning at 22.5 Torr has been
investigated experimentally using molecular beam sampling coupled with mass
spectrometric analysis. Mole fraction profiles have been obtained for stable
species as well as for atoms and radicals in a 17.9% CH2O - 82.1% O2 flame. From
data reduction it appears that about 80% of the formaldehyde is consumed in
radical reactions and about 20% by bimolecular decomposition. The fast reactions
of formaldehyde with atoms and hydroxyl radicals have the rate constants shown
below. Besides these processes, the decomposition reaction of formaldehyde (-83) could play a role in the
production of molecular hydrogen in this flame. Formyl radicals disappear mainly
by reaction (168) and this reaction
is the principal path for the hydroperoxyl radical production. This last species
reacts mainly with radicals and atoms (H, O, and OH). In the low temperature zone
of the flame, CO2 is produced by reaction (99) but also to some extent through
reaction (120).
REACTION RATE COEFFICIENTS SUGGESTED IN THIS WORK:
GRI-Mech
Number
('-' sign
means
reverse) |
Reaction |
Rate Coefficient
A T^n exp(-E/RT) |
Temperature
Range
(K) |
A
(mol,cm3,s) |
n
(T in K) |
E
(cal/mol) |
| 15 |
O + CH2O -> OH + HCO |
6.0E+13 |
|
3775 |
300-1600 |
| 58 |
H + CH2O -> HCO + H2 |
1.0E+14 |
|
4930 |
300-1600 |
| -83 |
CH2O + M -> H2 + CO + M |
2.5E+14 |
|
28315 |
1100-1600 |
| 101 |
OH + CH2O -> HCO + H2O |
1.8E+13 |
|
437 |
300-1600 |
| 120 |
HO2 + CO -> OH + CO2 |
3.5E+12 |
|
8196 |
1100-1500 |
| 167 |
HCO + M -> H + CO + M |
2.51E+15 |
|
18480 |
300-1600 |
| 168 |
HCO + O2 -> HO2 + CO |
2.7E+13 |
|
1195 |
300-1600 |