The effect of biomass pretreatment on catalytic pyrolysis products of pine wood by Py-GC/MS and principal component analysis

Non-catalytic and catalytic pyrolysis of pretreated pine wood was conducted using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Biomass pretreatment included acid-leaching, torrefaction, and acid-leaching followed by torrefaction. Forty-five pyrolysis products were identified in the Py-GC/MS chromatograms and their peak area data evaluated by principal component analysis. In non-catalytic pyrolysis, acid-leaching pretreatment enhanced the levels of levoglucosan, while torrefaction pretreatment enhanced the proportion of catechols in the volatile products. Increasing both the temperature and catalyst loading in catalytic pyrolysis promoted the formation of aromatic hydrocarbons. At lower pyrolysis temperatures (450-500 degrees C), acid-leaching pretreatment resulted in slightly lower proportions of aromatics, while torrefaction pretreatment had the opposite effect. Overall, temperature and catalyst loading were considerably more important factors in catalytic fast pyrolysis of pine wood than biomass pretreatment as studied by Py-GC/MS.