Résumé
This study introduces a novel analytical method to decouple the two main decomposition steps of bio-based materials during smouldering: pyrolysis and char thermo-oxidation. Using mass-loss deconvolution and methane as a tracer, the approach tracks the initial pyrolysis stage, as methane is produced exclusively during this first step. Analysis of gases at microscale using a PCFC-FTIR coupling, and additional tests on charcoal under varying heat fluxes (15, 20, 50 kW/m²), confirm that methane is not emitted during char thermo-oxidation. (1). The method relies on mass-loss and heat-release deconvolution, where the total MLR [1] and HRR [2] are expressed as the sum of contributions from pyrolysis and char oxidation [3], using their respective effective heats of combustion. Methane emissions are incorporated through a proportionality factor RCH4, defined as the ratio of total methane production to total mass loss, enabling methane to be used as a specific tracer of the pyrolysis stage [4,5]. This combined condensed and gas-phase approach provides a consistent framework to better interpret smouldering degradation mechanisms in bio-based materials.