VOLATILE PRODUCTS OF OXIDATIVE PYROLYSIS OF WOOD - INFLUENCE OF METAL-IONS

The volatile products from pyrolysis of wood in air have been determined by coupled thermal gravimetry/Fourier transform infrared spectrometry (TG/FTIR), both isothermally at 523 K and with progressive heating to 750 K. The results are compared with a similar early study of pyrolysis in nitrogen. The presence of oxygen increases the rate and extent of formation of water and of carbon dioxide at 523 K and induces the formation of carbon monoxide. Removal of indigenous metal ions and replacement by potassium or by calcium ions showed that catalysis by potassium of both pyrolysis and oxidation is dominant in wood for most types of reaction channel. At higher temperatures the influence of the potassium ions is very marked in catalysis of char oxidation by air, resulting in ignition and sudden formation of carbon monoxide, carbon dioxide, and water. © 1990.