Reactivity of char from pyrolysis of birch wood

Abstract

Pyrolysis of biomass from birch was carried out both in a free-fall tubular reactor and a thermobalance. The char obtained was further gasified with carbon dioxide and steam in the thermobalance. It was observed that the reaction rates of the char with the reagents were strongly affected by the time-temperature history of the char formation. A rapid heating rate of the raw material in free-fall reactor gives a char which possesses higher reactivity in reaction both with carbon dioxide and steam compared with the char formed under slow heating rate in the thermobalance. The treatment condition and environment of the char precursor during devolatilization are the most important factors affecting the reactivity of the char in gasification with the used reagents. The kinetic study focused on whether a surrounding pyrolysis gas atmosphere exerts negative effects on the reactivity of the formed char.