Pyrolysis behavior of cellulose in a fixed bed reactor: Residue evolution and effects of parameters on products distribution and bio-oil composition

Abstract

Significant discrepancies of cellulose pyrolysis behavior in a micro-scale pyrolyzer and that in a large-scale reactor hinder the industrial application of those findings obtained from the former reactor. In this work, the pyrolysis behavior of cellulose in a fixed bed reactor was investigated, especially the residue evolution and the effects of temperature, material thickness and carrier gas flow rate on the products distribution and bio-oil composition. And a possible pathway for the cyclopentanones formation was proposed and competing reactions during cellulose pyrolysis with the consideration of heat and mass transfer effect were analyzed. It was found that high temperature promoted the cellulose decomposition and favored the cellulose to produce furfural, cyclopentanones and light linear compounds (such as acetic acid, hydroxy actaldehyde), and relative low temperature (<450 °C) and thicker material thickness (>2 mm) favored the dehydration of cellulose to yield levoglucosenone and furans compounds, and fast carrier gas flow rate declined the yield of most compounds but favored the recovery of levoglucosan. The findings of present study, to some extent, could provide guidance on process optimization of cellulose pyrolysis in a large-scale reactor to produce desired chemicals.