Sulfur-catalyzed recombination of atomic oxygen in a CO/O/sub 2/Ar flame
Flame structure has been determined for two fuel lean, premixed laminar CO/O/sub 2//Ar flames, one of which contained 1.2% SO/sub 2/ by volume. At distances greater than 0.3 cm from the flameholder, the structure of the SO/sub 2/ doped flame was found to be consistent with a state of balance between the reactions O + SO/sub 2/ + M reversible SO/sub 3/ + M and SO/sub 3/ + O ..-->.. SO/sub 2/ + O/sub 2/. The catalytic recombination of O atoms practically eliminated the approx. 30% O-atom superequilibrium overshoot for the sulfur free flame. Sulfur addition resulted in a considerable increase in temperature, ranging from 50/sup 0/K near the flameholder to approx. 200/sup 0/K 1 cm downstream. Flame structures were modeled by solving simultaneously the one-dimensional, unsteady conservation equations using an oxidation mechanism including 14 species and 24 elementary reactions. Good agreement was obtained with the experiment. Both the experimental measurements and calculations indicate that sulfur addition has an inhibiting effect on the flame by catalyzing the recombination of chain carriers. The reaction H + O/sub 2/ ..-->.. OH + O is responsible for most of the chain branching and therefore strongly influences both flame speed and thickness. The CO + O + M ..-->.. CO/sub 2/ + M is the major channel for consumption of atomic oxygen and also produces about half of the CO/sub 2/. HSO/sub 2/ chemistry should also be included to accurately predict O, OH, or H profiles in the presence of sulfur, even for a flame with as little as 150 ppM H.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5454965
- Report Number(s):
- UCRL-87178; CONF-820320-1; ON: DE82010752
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ARGON
ATOMS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COMBUSTION
ELEMENTS
FLAMES
FLUIDS
GASES
NONMETALS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
RARE GASES
RECOMBINATION
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SULFUR TRIOXIDE
THERMOCHEMICAL PROCESSES