Effect of pyrolysis reaction kinetics modified by adding inorganics on flame spread of cellulose

The influence of pyrolysis reaction parameters on the flame spread rate over a thin cellulose strip was examined for varying additive amounts of an inorganic compound (K2CO3). The increase in the mass fraction of K2CO3 in the sample causes a decrease in the flame spread rate. Above 1.8% in K2CO3, the flame experiences extinction and smoldering occurs. The results of kinetic analysis reveal that the rate of pyrolysis reaction rate is decreased with the increase of K2CO3. To elucidate the decrease in the flame spread rate by the suppression of the pyrolysis reactions, the influence of the change of the flame temperature by various pyrolysis gas compositions or the pyrolysis reaction rate on the flame spread rate is examined theoretically. With regard to the temperature effect, the estimated adiabatic flame temperature decreases weakly with the increase of the K2CO3, which implies a weak contribution of the flame temperature to the flame spread rate. The results of theoretical analysis reveal that the reduction of the flame spread rate comes from the suppression of the pyrolysis reactions by adding K2CO3.