Direct liquefaction of lignin and lignin rich biomasses by heterogenic catalytic hydrogenolysis

As part of an ongoing project at Karlsruhe Institute of Technology (KIT), Germany, this work examines the liquefaction of varying feedstocks under conditions of the Bergius process of direct coal liquefaction by high pressure heterogeneous catalytic hydrogenolysis. Applying this process onto renewable resources like lignin and lignin-rich biomass has the potential to produce aromatic components for chemical industry.The performed experiments investigate the chemical conversion of different lignin types alongside samples of beech bark and beech wood fiber residues from pulp and paper industry using different heterogeneous catalysts and catalyst preparations. Reaction conditions such as catalyst concentration, temperature and concentration of sulfur were varied in order to optimize the conditions of liquefaction for the chosen setup.It will be shown that lignin and lignin-rich biomass can be liquefied under conditions of direct coal liquefaction using molybdic acid and sulfidic iron catalysts. The liquid oil product can be obtained in good yields up to 60% mass fraction of the input feedstock, consisting of alkylated phenols and alkyl benzenes while removing the majority of hetero atomic functional groups. This can be achieved while producing only a minimal amount of solid residue, reaction water and a valuable gas byproduct.