Abstract
The kinetics and mechanisms of soot oxidation were studied at temperatures of 1575 to 1865 K and O2 mole fractions of 10−5 to 0.05 in a two-stage atmospheric-pressure combustion system in which soot-laden gas from a primary flame was partially cooled, mixed with oxygen-containing gas, and burned in a downstream premixed flame. The rate of oxidation of soot was measured using light scattering and absorption techniques to determine the particle size and concentration of soot as a function of distance, and hence of time, in the secondary flame. Complementary measurements of soot particle size were performed using probe sampling, electron microscopy, and electrical mobility analysis, and the specific surface area of the soot at different stages of burnout was measured by the BET technique. Temperature and gas composition profiles in the secondary flame were determined using coated thermocouples with electrical compensation for radiation loss, chromatographic analysis of sampled stable gases, and a spectroscopic technique combined with partial equilibrium calculations for radical species. It was found that OH radical is the principal oxidant of soot under these conditions, with O2 being of secondary importance. The average value of the collision efficiency of OH with soot is found to be 0.28 if the optical (equivalent sphere) diameter of the soot aggregates is used in the calculations, or about 0.13 if the diameter of the individual spherical units within the aggregates is used. The actual value of the collision efficiency is expected to be bounded by these two values. The results indicate that soot burnout rates predicted from the Nagle and Strickland-Constable formula, which assumes O2 to be the oxidant, are drastically underestimated under fuel-rich flame conditions owing to the neglect of the OH contribution. Breakup of soot aggregates during burnout was observed under fuel lean conditions.
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References
J. Nagle, and R. F. Strickland-Constable, Proc% of the Fifth Carbon Conf: l (1962), p. 154.
D. E. Rosner, and H. D. Allendo,f; AIAA Journal, Vol. 6 (1968), p. 650.
F. J. Wright, “Fifteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1975), p. 1449.
C. Park, and J. P. Appleton, Combustion and Flame, Vol. 20 (1973), p. 369.
M. Otterbein, and L. Bonnetain, Carbon, Vol. 7 (1969), P. 539.
J. R. Walls, and R. F. Strickland-Constable, Carbon, Vol. 1 (1964), p. 33.
D. R. Glander, W. Siekhaus, R. Jones and J. A. Schwarz, J. Chem. Phys., Vol. 57 (1972).
K. B. Lee, M. W. Thring, J. M. Beer, Combustion and Flame, Vol. 6 (1962), p. 137.
P. A. TesnerandA. M. Tsibulersky, Combustion, Explosion, and Shock Waves, Vol. 3 (1967), p. 163.
P. A. Te seer, and A. M. Tsibule rsky, Combustion and Flame, Vol. 11 (1967), p. 227.
C. P. Fenimore and G. W. Jones, J. Phys. Chem., Vol. 7/ (1967), p. 593.
J. P. Appleton, “Soot Oxidation Kinetics at Combustion Temperatures”, Paper presented at AGARD Propulsion and Energetics Panel, 41st Meeting, London, England, April (1973).
S. W. Radcliffe, and J. P. Appleton, Combust. Sci. and Tech., Vol. 4 (1971), p. 171.
G. Reinhold, P. Szargan, P. Nan, and K. Richter, Chem. Techn., Vol. 23 (7) (1971), p. 416.
W. J. Thomas, Carbon Vol. 3 (1966), p. 435.
A. D’Alessio, A. DiLorenzo, A. F. Sarofïm, F. Beretta, S. Masi, and C. Venitozzi, “Fifteenth Symposium (International) on Combustion,” The Combustion Institute, Pittsburgh, (1975), p. 1427. -
E. M. Buleu’icz, C. G. James, and T. M. Sugden, Proc. Roy. Soc. A235 (1956), p. 89.
M. J. McEuan, and L. F. Phillips, Combustion and Flame, Vol. 9 (1965), p. 420.
K. G. Neoh, “Soot Burnout in Flames’’, Sc.D. Thesis, Department of Chemical Engineering, Massachusetts Institute of Technology, in preparation.
W. H. Datte/(, G. C. Williams, and H. C. Hottel, Combustion and Flame, Vol. 14 (1970), p. 161.
H. A. Becker, and S. Yamazaki, “Sixteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1977), p. 681.
B. F. Magnussen, “Fifteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1975), p. 1415.
B. F. Magnussen, and B. H. Hjertager, “Sixteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1977), p. 719.
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Neoh, K.G., Howard, J.B., Sarofim, A.F. (1981). Soot Oxidation in Flames. In: Siegla, D.C., Smith, G.W. (eds) Particulate Carbon. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-6137-5_9
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DOI: https://doi.org/10.1007/978-1-4757-6137-5_9
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