Direct Coupled Catalytic Upgrading of Multi-Stage Pyrolysis Bio-Oil Vapors

A two-stage pyrolysis was conducted in this work. The purpose of the multiple stages is to provide a segregated product evolution in which the vapor products maybe be more selectively treated by catalysts to improve product quality and catalyst stability in comparison to one step pyrolysis in which all components of the bio-oil vapor are present, complicating the upgrading requirements to achieve high yield. This particular two-stage configuration is designed to remove much of the light oxygenates (acetic acid, water, acetol, acetaldehyde) and sugar derived components (furfurals, levoglucosan, pyrans, etc.) in the first stage, with a more concentrated lignin derived phenolics stream produced from the high temperature fast pyrolysis stage. The phenolics rich vapor from the high temperature stage is treated by a dual function metal and oxide catalyst bed with hydrogen at atmospheric pressure coupled to the exit of the pyrolysis reactor.