Base-catalysed depolymerization of lignins in supercritical water: Influence of lignin nature and valorisation of pulping and biorefinery by-products

Different lignins from different sources (hardwoods, softwoods and crop residues) obtained as by-products of processes such pulping or biorefining were depolymerized in alkaline supercritical water (SCW: 386 °C 260 bar) an intensified continuous process to produce high value-added compounds with low-molecular-weight only 300 ms reaction time. The products analysed determine the yield, selectivity monomers, chemical structure molecular weight distribution. char formation was low most cases, but proportion heavy light oils variable upon starting material used. monoaromatics yield depends mostly on type lignin utilized being non-wood biorefinery less suitable for monomers production than technical wood ones (13-8%). monomer distribution biomass origin method. This technology is equally effective when directly treating a black liquor better results are if compared corresponding isolated lignin.