Fast pyrolysis of sawdust was performed and the pyrolysis vapors were analyzed with on-line pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS).Two catalysts

zeolite HZSM-5 and mesoporous SBA-15

were tested to determine their actions on the pyrolysis vapors.The catalytic cracking of the pyrolysis vapors with HZSM-5 significantly decreased the yields of acetic acid

hydroxyacetaldehyde

furans and phenols

and meanwhile a lot of aromatic hydrocarbons were formed

mainly toluene and xylenes.The catalytic cracking of the pyrolysis vapors with SBA-15 decreased the yield of acetic acid

slightly decreased the yield of hydroxyacetaldehyde

and increased the yields of furans and phenols.The results indicated that the two catalysts exhibited different catalytic cracking actions on the pyrolysis vapors.HZSM-5 was highly active in deoxygenation of the pyrolysis vapors.SBA-15 possessed very little activity to catalyze the pyrolysis vapors to form hydrocarbons

but its mesoporous structure allowed cracking of large molecules to smaller sawdust compounds.