Simulations of isothermal oven tests of impregnated activated carbons in cylindrical and cubic sample holders

摘要

Isothermal oven exposure tests using cylindrical and cubic sample holders are conducted in air on a 14% (w/w) K2CO3-impregnated activated carbon at temperatures between 115 and 200 degreesC. Such oven tests are widely performed on potentially selfheating materials in agreement with IATA regulations concerning the transportation of dangerous goods. The thermal behavior of this respirator carbon in both holder geometries of various sizes was simulated successfully at various temperatures, including conditions leading to thermal runaway. Finite element mathematics, oxygen diffusion, heat transfer and kinetic theories are the basis of the simulation algorithm. For the carbon studied here, the reaction takes place in two apparently independent processes. In the first process, the surface functional groups decompose, and the carbon reacts with the oxygen in air in the second process. The vaporization of moisture is also introduced in the reaction model. The kinetic triplets (activation energy, frequency factor and kinetic model) of these processes were previously determined using isothermal DSC and were incorporated into the simulation algorithm. (C) 2004 Elsevier Ltd. All rights reserved.