Pyrolytic spray increases levoglucosan production during fast pyrolysis

Levoglucosan is the major anhydrosugar component of bio-oil produced by fast pyrolysis. Previous research has shown that levoglucosan yield can be greatly increased if a mild acid pretreatment is applied to demineralize the feedstock prior to pyrolysis. The interest in levoglucosan production is that it provides a route to production of monomeric sugars, primarily glucose, which can be utilized to produce biochemically derived fuels (ethanol, butanol, etc.). This study developed a new method based on pyrolysis of clear pinewood particles with dilute acid pretreatment and modification in the pyrolysis process by applying a water spray injection directly into the pyrolysis vapor stream. This new method resulted in a significant 30.7% increase in levoglucosan weight percentage based on the bio-oil organic portion. The results indicated that this rapid quenching in pyrolysis vapor stream successfully suppressed the levoglucosan decomposition in both the vapor stream and during condensation. This increase may change the process economics of production of anhydrosugars via pyrolysis.