Monitoring pine wood thermolysis under hydrogen atmosphere by in situ and ex situ techniques

The behavior of lignocellulose and the products released during decomposition under hydrogen or argon were investigated through two different approaches: (i) in situ techniques by TGA coupled with gas phase FTIR spectroscopy and temperature resolved DRIFTS with online GCMS. These techniques provide the decomposition profile, the evolution of the wood surface structure and identification of the released compounds. (ii) Ex situ experiments where three fractions (gas, liquid, solid) were obtained in notable quantity and separated after the decomposition. GC, GCMS, NMR, FTIR and elemental analysis were used to characterize the products. The combination of these characterization techniques showed that the decomposition of the pine wood starts from the holocellulosic part around 275 °C producing light oxygenated compounds such as furfural derivate. Lignin structure degrades at temperatures higher than 350 °C leading to formation of phenolic compounds.