Kinetics of high temperature biomass conversion

Biomass pyrolysis at high heating rates was investigated for temperatures between 900 and 1540 K, by means of shock tube experiments. Cellulose, lignin and pinewood were the considered materials. Heat transfer calculations indicate that the burnout times below 1100 K were mainly kinetically dominated. Low activation energies were found, particularly for cellulose and pinewood. This appears to be typical for the first decomposition reaction. A heating wire grid reactor was used to carry out char gasification experiments in CO₂. The char was obtained by pyrolysis of pinewood and produced under different conditions (temperature, pressure, hold time and heating rate). The char gasification rate appeared to depend significantly on the char production conditions. For one char the gasification temperature and pressure was varied. In this way the activation energy and the order of the gasification reaction was investigated.