Thermogravimetric analysis of the combustion of dry distiller's grains with solubles (DDGS) and pyrolysis char under kinetic control

The combustion behavior of dry distiller's grains with solubles (DDGS) and the corresponding pyrolysis charusing a thermogravimetric system is studied. Comparison with beech wood indicates that DDGS devolatilizationoccurs with a slower rate and the char consists of two fractions with different reactivity. Thermogravimetriccurves, obtained with heating rates between 2.5 and 20 K/min, are used to develop a multi-step global reactionmechanism. The description of DDGS devolatilization requires four reactions, representative of the evolution oflumped classes of components, with activation energies of 95, 107, 106 and 100 kJ/mol, which are lower thanthose typically associated with wood devolatilization. DDGS char combustion is well described by two reactionsteps with activation energies of 137 and 153 kJ/mol that again barely touch the lower limit of the typicalrange of values reported for lignocellulosic chars