Fast Pyrolysis of Biomass for Recovery of Specialty Chemicals

Abstract

Many plant materials contain minor amounts, often only in the 100 ppm range, of complex compounds which may have a considerable present or potential application in biological or pharmaceutical areas. Extraction and concentration of these specialty chemicals by conventional technology can be a laborious and costly process.

Examples are given in which fast fluid bed pyrolysis has been used in our research to obtain pyrolysis liquids considerably enriched in such compounds, even when they have very low volatilities. One example involves the recovery of an alkaloid from plant leaves. Another feedstock gives complex terpene-based compounds (taxanes) which can be precursors for synthesis of new antitumor agents, or that can be used as a potential plant fungicide. Additional examples of complex compounds obtained in significant yields in fast pyrolysis oils can be found in the high molecular weight lignin fragments, largely aromatic in character, which are a part of the “pyrolytic lignin” fraction of a pyrolysis oil; and in the anhydrosugar monomers, dimers and oligomers obtained from the carbohydrate fraction of biomass on fast pyrolysis.

Some unique features, and some speculations on mechanisms, of such specialized pyrolytic processes are discussed.