Flame inhibition by halogen compounds

Molecular basis of flame inhibition

“…The need for such models has recently been emphasized by Fristrom and Sawyer [9], and these authors have developed a model which allows the definition [42] where, in the presence of an inhibitor, the pre flame zone is extended and the reaction zone narrows. Inhibition is considered to occur primarily in the pre flame region where the chain branching reaction is slow and radical recombination is more important.…”

“…A more detailed description of the likely flame inhibiting mechanism has been derived from experiments carried out at the molecular level, such as the mass spectrometric microprobe sampling experiments described by Wilson et al [42], or by Pownall and Simmons [54].…”

“…Wilson et al [42] have obtained indirect evidence for an increase in the maximum OR level in low pressure lean CH 4 -0 2 flames containing HBr. However, using 1 atm lean propane fueled flames, Pownall and Simmons [54] provide indirect evidence for a reduction in the maximum OH concentration in the presence of HBr.…”

“…However, more recently, Wilson and co-workers [42] have suggested an alternative mechanism involving H-atom reactions.…”

“…The primary reactions responsible for flame propagation are generally agreed to be: From the low pressure flame mass spectrometric studies reported by Wilson et al [42], it is evident that the introduction of halogen species into a premixed C~/02 flame ler.ds to the production of the hydrogen halide, HX, early in the flame. It was observed that the formation of H2CO is inhibited and the production of H2 enhanced.…”