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Flame Inhibition by Ferrocene, Alone and With CO2 and CF3H.


pdf icon Flame Inhibition by Ferrocene, Alone and With CO2 and CF3H. (1168 K)
Linteris, G. T.; Rumminger, M. D.; Babushok, V. I.

Halon Options Technical Working Conference. Proceedings. HOTWC 2000. Sponsored by: University of New Mexico, Fire Suppression Systems Assoc., Fire and Safety Group, Great Lakes Chemical Corp., Halon Alternative Research Corp., Hughes Associates, Inc., Kidde Fenwal, Inc., Kidde International, Modular Protection, Inc., Next Generation Fire Suppression Technology Program, Sandia National Laboratories, Summit Environmental Corp., Inc. and 3M Specialty Materials. May 2-4, 2000, Albuquerque, NM, 129-140 pp, 2000.

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For more information contact: Center for Global Environmental Technologies, New Mexico Engineering Research Institute, University of New Mexico, 901 University Blvd., SE, Albuquerque, NM 87106-4339 USA.
Telephone: 505-272-7250,
Fax: 505-272-7203. WEB: http://nmeri.unm.edu/cget/confinfo.htm

Keywords:

halon alternatives; flame extinguishment; carbon dioxide; premixed flames; experiments; numerical models; halons

Abstract:

Iron pentacarbony1 (Fe(CO)5) is an extraordinarily effective flame inhibitor, up to two orders of magnitude more efficient than CF3Br at reducing the burning velocity of premixed flames. Recent progress has been made in understanding its mechanism of inhibition. However, it is flammable and highly toxic, and addition at mole fractions above a few hundred ppm does not result in further flame speed reduction. If other non-toxic forms of iron exist, which are also superb inhibitors and which maintain their action up to higher mole fractions, they could lead to the development of very effective fire suppressants. Previous research has shown that iron atom in the gas phase leads to the inhibiting iron-species intermediates, and that the main property required for the parent molecule is that it readily decomposes at flame temperatures to release iron atom. A possible alternative source of Fe is ferrocene (Fe(C5H5)2 or Fec). Ferrocene modifies the sooting tendency of flames, is added to materials as a flame retardant, is an antiknock agent, and is used as a source of iron atoms for kinetic studies. It is also far less toxic than Fe(CO)5. In this work we present the first measurements of flame inhibition by ferrocene, and compare its performance with that of Fe(CO)5 and CF3Br in the same flames. We numerically model Fec's flame inhibition using the iron-species mechanism developed for studies of Fe(CO)5 flame inhibition. Finally, we present results on the performance of Fec in combination with other agents, including CO2, and CF3H. The present research demonstrates that the efficiency of Fe(CO)5 is not unique and that there are methods for overcoming its loss of performance.