INHIBITOR INFLUENCE ON THE BISTABILITY OF A CSTR

Methane combustion in a continuously stirred flow tank reactor (CSTR) in the presence and absence of chemical inhibitors such as CF3I, CF3Br , CF3H, and a chemically inert gas witt high heat capacity is simulate d with the CHEMKIN program. The aim of the work is to determine the di fferences in results arising from the use of the various inhibitors wi th the aim of establishing the capability of CSTR experiments to give a rank ordering of suppressant power. The chemical inhibitors have the general tendency to raise the steady-state temperature. A high heat c apacity inert gas leads to the opposite effect. Only near extinction a nd self-ignition can one obtain a proper scale of flame suppression ca pability. The curves for combustion efficiency, (CO2/[CO + CO2]), near the extinction point lead to results where the data for the additives all fall within the envelope for stoichiometric methane/air combustio n in the extinction region. For self-ignition, the transition from the mushroom to the isola form of the stability curves appears to be anot her property that is highly sensitive to suppression power. These obse rvations may serve as a basis for testing inhibition capabilities. Cop yright (C) 1997 by The Combustion Institute