(635b) Pyrolysis and Electrocatalysis of Biorefinery-Derived Lignin to Make Hydrocarbon Fuels

Conversion of the more than one billion tons of biomass that may be available in 2030, as per the U.S. Billion-ton Study, could result in as much as 300 million dry tons of lignin. Uses of this lignin span from low value combustion heat to high value food flavorings and antioxidants.  Routes to liquid hydrocarbon fuels could improve the economics and energetics of biorefineries that produce ethanol.  Lignin, comprising up to 30% of the mass and 40% of the energy stored in biomass, offers great potential as feedstock for biomass-based liquid fuel production when using fast pyrolysis as an intermediate step. Lignin is and will continue to be a major byproduct of cellulosic ethanol production. We propose implementing pyrolysis for lignin depolymerization and conversion to liquid fuels or value added products. However, the most valuable of the pyrolysis products, bio-oil is highly oxygenated, corrosive, low in energy content and unstable during storage. As a means of improving bio-oil properties, electrocatalytic hydrogenation (ECH) is employed to reduce and deoxygenate reactive compounds. In this study, lignin model compounds representative of bio-oil components are subjected to ECH under mild conditions (80°C and 1atm) using ruthenium on activated carbon cloth  (Ru/ACC) as a catalytic cathode.  To date, model monomers (guaiacol, syringol and phenol) and model dimer (4-pehnoxyphenol) have successfully been reduced using this method. Further work in this area focuses on pyrolysis and electrocatalysis of ammonia extracted lignin.