Abstract
Although numerous chemical mechanisms have been postulated for the formation of soot in hydrocarbon combustion, none have received quantitative support. Understanding of this process is complicated by the large number of species involved and by the phase change associated with nucleation.
An experimental program is underway at AeroChem to determine the role of ionic processes in soot formation in premixed hydrocarbon flames. The hypothesis being tested is that ions produced via chemi-ionization serve as nuclei for initial formation of soot particles. Rapid ion-molecular kinetics, rapid structural rearrangements, and thermochemistry favorable toward growth to larger species are characteristics of the ion chemistry, in agreement with observations about the soot formation process.
Mass spectrometric measurements of flame ion concentration profiles have been made in low pressure rich and sooting acetylene/oxygen and benzene/oxygen flames. As both flames are made increasingly fuel rich and approach sooting the predominant ion C3H3 + is replaced by large positive aromatic ions with mass greater than 300. It is argued that these ions are the soot precursors.
Similarities and differences betweeen the ion spectra of rich and sooting acetylene and benzene flames are discussed along with possible reasons for dual maxima in ion concentration profiles observed in sooting flames. A detailed chemical mechanism considering both neutral and ionic flame chemistry is being developed for which it is necessary to estimate the thermochemical parameters for large ionic species. Preliminary results of computer simulations of the chemical kinetics using this scheme are presented. The results are consistent with an ionic mechanism of soot formation.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
H. B. Palmer and C. F. Cullis, in “Chemistry and Physics of Carbon,” P. L. Walker, Ed., Marcel Dekker, New York, Vol. 1(1965), p. 265.
H. F. Calcote, March, 1980; Accepted for publication in Combust. and Flame.
D. B. Olson and H. F. Calcote, “Eighteenth Symposium (International) on Combustion,” The Combustion Institute, Pittsburgh, (in press).
H. F. Calcote, “Eighth Symposium ( International) on Combustion,” Williams and Wilkins Co., Baltimore, (1962), p. 184.
J. Peeters and C. Vinckier, “Fifteenth Symposium ( International) on Combustion,” The Combusition Institute, Pittsburgh, (1975), p. 969.
J. W. McGowan, P. M. Mul, V. S. D’Angelo, J. B. A. Mitchell, P. Defiance and H. R. Froelich, Phys. Rev. Lett., Vol. 42 (1979), p. 373.
H. F. Calcote and W. J. Miller, in “Reactions Under Plasma Conditions,” M. Venugopalan, Ed., John Wiley & Sons, New York, Vol. 2 (1971), p. 327.
J. M. Goodings, D. K. Bohme and T. M. Sugden, “Sixteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1977), p. 891.
H. F. Calcote, in “Ion-Molecule Reactions,” J. L. Franklin, Ed., Plenum Press, New York, Vol. 2 (1972), p. 673.
W. J. Miller, “Eleventh Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1967), p. 311.
H. F. Calcote, S. C. Kurzius and W. J. Miller, “Tenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1965), p. 605.
G. P. Glass, G. B. Kistiakowsky, J. V. Michael and H. Niki, J. Chem. Phys., Vol. 42 (196.5)p. 608.
P. F. Knewstubb and T.M., Sugden, “Seventh Symposium ( International) on Combustion,” Butterworths, London, (1959), p. 247.
W. J. Miller, Oxid. Combust. Rev., Vol. 3 (1968), p. 97.
R. J. Bowser, and F. J. Weinberg, Combust. Flame, Vol. 27 (1976), p. 21.
G. Prado and J. B. Howard, in “Evaporation-Combustion of Fuels,” J. T. Zung, Ed., American Chemical Society, Washington, DC, (1978) p. 153.
B. L. Wersborg, A. C. Yeung and J. B. Howard, “Fifteenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1975), p. 1439.
J. L. Delfau, P. Michaud and A. Barassin, Combust. Sci. Technol., Vol. 20 (1979), p. 165.
K. H. Homann, Ber. Bunsenges. Phys. Chem., Vol. 83 (1979), p. 738.
D. E. Jensen and W. J. Miller, J. Chem. Phys., Vol. 53 (1970), p. 3287.
J. D. Bittner, and J. B. Howard, “Eighteenth Symposium (International) on Combustion,” The Combustion Institute, Pittsburgh, (in press).
P. Michaud, personal communication, (1980).
S. G. Lias and P. Ausloos, “Ion-Molecule Reactions. Their Role in Radiation Chemistry,” The American Chemical Society, Washington, DC, (1975), p. 94.
T. Tanzawa and W. C. Gardiner, Jr., “Seventeenth Symposium ( International) on Combustion,” The Combustion Institute, Pittsburgh, (1979), p. 563.
T. Tanzawa and W. C. Gardiner, Jr., J. Phys. Chem., Vol. 84 (1980), p. 236.
S. E. Stein, J. Phys. Chem., Vol. 82 (1978), p. 566.
S. E. Stein, D. M. Golden and S. W. Benson, J. Phys. Chem., Vol. 81 (1977), p. 314.
H. M. Rosenstock, K. Draxl, B. W. Steimer and J. T. Herron, J. Phys. Chem. Ref. Data, Vol. 6 (1977), Suppl. No. 1.
R. G. McLoughlin, J. D. Morrison and J. C. Troeger, Organic Mass Spectr. Vol. 14 (1979), p. 104.
R. D. Bowen and D. H. Williams, J. Amer. Chem. Soc., Vol. 100 (1978), p. 7454.
D. R. Stull and H. Prophet, “JANAFThermochemical Tables,” Second Ed., NSRDSNBS-37, National Bureau of Standards, Washington, DC, (1971).
R. S. Duff and S. H. Bauer, J. Chem. Phys., 36 (1962), p. 1754.
C. J. Jachimowski, Combust. Flame, Vol. 29 (1977), p. 55.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1981 Springer Science+Business Media New York
About this chapter
Cite this chapter
Olson, D.B., Calcote, H.F. (1981). Ionic Mechanisms of Soot Nucleation in Premixed Flames. In: Siegla, D.C., Smith, G.W. (eds) Particulate Carbon. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-6137-5_7
Download citation
DOI: https://doi.org/10.1007/978-1-4757-6137-5_7
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4757-6139-9
Online ISBN: 978-1-4757-6137-5
eBook Packages: Springer Book Archive