Sawdust pyrolysis oils, fractionation

Figure 3. Pine sawdust pyrolysis oil fractionation scheme. Yields are on a dry basis.

Figure 6. CP/MAS 13C-NMR of novolaks a) phenol-formaldehyde b) phe-nol phenols/neutrals (1 1) pine sawdust pyrolysis oil fraction and formaldehyde.

Table II. Fractionation of Sawdust Pyrolysis Oils Yields (% on dry oil basis)...

Figure 5. High-performance size exclusion chromatograms of pine sawdust pyrolysis oils and fractions of acids, phenols, and neutrals contained in the ethyl acetate soluble oil.

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. 

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