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Anionic Effects in Hot Surface Combustions.


pdf icon Anionic Effects in Hot Surface Combustions. (573 K)
Bannister, W. W.; Donatelli, A.; Bonner, F.; Lai, F.; Kurup, P.; Egan, J.; Jahngen, E. G. E.; Muanchareon, P.; Paramasawat, W.; Sriseubsai, W.; Chiang, S. K.; Kongkadee, V.; Sengupta, S.; Nagarajan, R.; Euaphantasate, N.; Parma, V.; Cazeca, M.; Chen, E.; Morales, A.

Paper 22; HOTWC 2005;

Halon Options Technical Working Conference, 15th Proceedings. HOTWC 2005. Sponsored by: 3M Specialty Materials, Boeing, Chemical Development Studies, Inc., DuPont Fire Extinguishants, Halon Alternative Research Corp., Hughes Associates, Inc., Kidde-Fenwal, Inc., Sandia National Laboratories, SEVO Systems, Next Generation Fire Suppression Technology Program. May 24-26, 2005, Albuquerque, NM, 1-13 pp, 2005.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Keywords:

halon alternatives; halons; halon 1301; combustion; hot surfaces; equations; oxidation; ignition; hydrocarbons; electrostatic charges

Abstract:

Hot surface oxidations are commonly thought to involve initial free radical hydrogen atom abstraction. Our evidence implicates initial Lewis base deprotonation by O atomic oxygen radical anions to form negatively charged carbanions. Subsequent rate determining electron transfers generate free radicals which only then give rise to combustion. Correlations regarding ignition temperatures and hydrocarbon oxidation product identity are consistent with carbanionic but not free radical effects. Highly polarized surfaces (e.g., quartz and corroded surfaces), and addition of polar compounds to fuel/air mixtures facilitate ignitions. EFM confirms increased electrostatic intensities at microscopic surface defects. For seemingly uniformly hot surfaces there are transient widely disparate high temperature incandescent "red spot" zones due to flameless oxidations induced by concentrated electrostatic negative charges at surface defects. Isotope, ignition temperatures and combustion trends are consistent with Seebeck effects (ease of electron migration in unevenly heated areas). There are preliminary though not yet verified indications that electrostatic charges on hot surfaces may facilitate combustion. Implications would then involve fire mitigation and enhancement, and industrial manufacture of many important organic combustion products.