A kinetic model for the direct thermal liquefaction of pine wood
Reaction network and quantitative kinetic model for lignocellulosic biomass conversion via direct thermal liquefaction
A kinetic model has been developed for the conversion of lignocellulosic biomass, namely pine wood, using the direct thermal liquefaction technique into three major products: vacuum residue (\(M_w\) > 1000 Da), distillate (\(M_w\) < 1000 Da), and gases. The kinetic model incorporates primary as well as secondary reactions, with parameters fitted using experimental data available in the literature.
Examination of the rate constants shows vacuum residue, distillate, and gases forming directly from the wood. Secondary reactions - such as VR to distillate, VR to gases, or distillate to gases - were found to be insignificant. A study of the solvent effect shows that a mixture of guaiacol and water (8:1 weight ratio) gave the highest overall rate constants of 2.2 \(\times\) 10\(^{-3}\) s\(^{-1}\) at 310°C. The use of water as a co-solvent (20 wt% of the total feed) was found to enhance all primary reactions by more than twice.
Among the individual studied constituents of wood, cellulose was revealed to be the least reactive constituent, while the whole wood shows the highest reactivity - in fact, wood was found almost 50% faster to decompose than cellulose.
Published in Biomass Conversion and Biorefinery (2025). BTech Thesis - Best Bachelor’s Thesis Award, IIT Roorkee. Advisor: Dr. Shushil Kumar.