Biomass Pyrolysis Oil Feedstocks for Phenolic Adhesives

Fast pyrolysis of pine sawdust in a small vortex reactor operating at 10 to 20 kg/h and 480 to 520 °C produces high yields of primary pyrolysis oils (over 55% by weight on a dry basis). The vortex reactor transmits very high heat fluxes to the sawdust, causing primarily depolymerization of the constituent polymers into monomers and oligomers. A preliminary scheme separates the raw oils into a carbohydrate-derived aqueous fraction and a phenolic-rich ethyl acetate (EA) soluble fraction. The EA fraction is washed with water and with aqueous sodium bicarbonate to remove acids yielding 20% to 25% of the feed as phenols and neutrals (P/N) in the EA solution. After EA evaporation, a novolak formulation with 50% phenol and 50% of the P/N fraction was successfully prepared. Gel times for the P/N fractions suitably prepared are intermediate between resorcinol and traditional phenol-formaldehyde resins. Preliminary projected amortized production costs for the P/N fraction are 10(16) cents per pound for a 1,000(250) tons per day plant ($10/dry ton feedstock, 15% interest with 20-year amortization).