Influence of Bond Energies on Catalytic Flame Inhibition: Implications for the Search for New Fire Suppressants

摘要

We have conducted computational investigations of the conditions necessary for a substance to be an efficient flame suppressant. Of particular interest is identification of additional chemical elements, which might be expected to have promising suppression properties, particularly by catalytic scavenging of flame radicals. Bromine, sodium, and iron are used as examples of prototypical H + H, H + OH, and 0+ 0 scavenging cycles, respectively. For each element, a simplified kinetic mechanism involving a single scavenging cycle was employed. The effect of hypothetical changes in bond dissociation energies on reduction of burning velocity of a premixed methane/air flame by these elements is determined. Efficient radical scavenging is possible only if a suppressant atom or radical binds to one of the primary flame radicals (H, 0, or OH) with a bond energy in the range of 70-100 kcal/mole.