Fire hazard evaluation of activated carbons

Abstract

Activated carbons are widely used in the iodine adsorbers in nuclear plants, but little information about their combustibility is available for fire engineers. Series of TGA experiments were conducted for activated carbons, charcoal and XPS foam. The results show that the activated carbons oxidize strongly in air atmosphere but little in N₂ atmosphere. The calculated activation energies of the wood AC, anthracite AC and coconut shell AC are, respectively, 100.56, 96.34 and 91.00 kJ mol⁻¹, which are larger than that of the XPS foam, 55.95 kJ mol⁻¹. However, the calculated activation energies of impregnated coconut shell activated carbon is 48.60 kJ mol⁻¹, which is smaller than that of XPS foam. A new parameter, A₁₂, is introduced to describe the amount of evaporative mass fraction during the fast pyrolysis stage. Additionally, the (T_p, DTG_p) map and quarter division method is introduced to compare fire hazard of different materials. Finally, a quantitative fire hazard evaluation model is developed based on four important parameters: E, DTG_p, T_p and A₁₂. The calculated Relative Fire Safety Factors by this model for wood AC, anthracite AC, coconut shell AC, impregnated coconut shell activated carbon, charcoal and XPS foam are 1.49, 1.91, 1.51, 1.37 and 1.0, respectively.