Formation of Anhydro-sugars in the Primary Volatiles and Solid Residues from Cellulose Fast Pyrolysis in a Wire-Mesh Reactor

Abstract

The unique design of wire-mesh reactors (WMR) enables the collection of primary volatiles with minimized secondary reactions from fast pyrolysis of solid fuels. This paper reports the formation of anhydro-sugars in both primary volatiles and solid residues from the fast pyrolysis of microcrystalline cellulose in a WMR. Under fast pyrolysis, cellulose is rapidly converted into an intermediate phase, and the maximal yield of the water-soluble intermediates achieved in this study is ∼21% on a carbon basis at 450 °C, much higher than those achieved in other pyrolysis reactor systems. The solid residue consists of sugar and anhydro-sugar oligomers with a wide range of degrees of polymerization (DPs). However, only anhydro-sugars with DPs up to 3 can be identified in the primary volatiles, and the presence of these anhydro-sugars is evident even at 300 °C. Because of high boiling points, cellobiosan and cellotriosan are impossible to be released into the vapor phase via evaporation under the conditions. These h...