Kinetics of Sulfur-Oxide Formation in Flames: II. Low Pressure H2S Flames
Open Access
- 1 December 1967
- journal article
- research article
- Published by Taylor & Francis in Journal of the Air Pollution Control Association
- Vol. 17 (12) , 800-806
- https://doi.org/10.1080/00022470.1967.10469073
Abstract
The microstructure of 1/10 and 1/20 atmosphere, lean H2S—O2—N2 flames is developed using the mass-spectrometric flame-sampling technique. The flame mechanism developed is in agreement with that determined from an earlier study on 1-atm H2S flames. The formation of SO2 appears to be primarily related to the production of SH and the ensuing oxidation steps SH + O2 = SO + OH and SO + O2 = SO2 + O. While there is some question whether SO2 formation occurs via an SO or an S2O intermediate, the present study does not give direct support to the role of S2O in the oxidation mechanism. However, the presence of significant quantities of free sulfur in the pre-flame zone may be indicative of S2O formation via SO + S → S2O, and, possibly, via the disproportionation of SO, 3SO → S2O + SO2. Kinetic analyses of some of the pre-flame reactions indicate an apparent activation energy of 17,300 calories/mole for the decomposition of H2S. The actual initiation process in the flame mechanism requires further examination. The specific rate for the reaction step H2S + O = OH + SH is given by k 6 = 1.45 × 1015 exp ( – 6600/RT) cm3 mole–1 sec–1, and the specific rate for the oxidation of SO, SO + O2 = SO2 + O, is given by k 5 = 5.2 × 1014 exp (—19,300/RT) cm3 mole–1 sec–1.Keywords
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