Online fast pyrolysis of cellulose over titanium dioxide using tandem micro-reactor-GC-MS

Abstract

In this work, the catalytic effect of titanium dioxide (TiO2) on the online fast pyrolysis of cellulose was investigated using a tandem micro reactor coupled to a gas chromatograph-mass spectrometer (GC-MS) system. This system was used in the following two different modes: in-situ and ex-situ. The results obtained with TiO2 were compared with those of zeolite (HZSM-5) under identical pyrolysis conditions. Levoglucosan was the major product in the non-catalytic pyrolysis of cellulose. As for the catalytic pyrolysis of cellulose at 500 °C with TiO2 (in-situ), the peak of levoglucosan disappeared whereas aromatic hydrocarbons such as benzene, toluene and naphthalene were newly detected. In this case, oxygenated compounds such as furfural, furan, methylfuran were still observed for TiO2 whereas oxygenated compounds (i.e, furan, benzofuran, methylbenzofuran, acetone and 2-butanone) with low yields were observed for in-situ catalytic pyrolysis with HZSM-5. For ex-situ catalytic pyrolysis of cellulose at 500 °C using TiO2, oxygen-containing compounds were hardly formed, while various aromatic hydrocarbons were detected. When the ex-situ pyrolysis of cellulose with HZSM-5 was carried out, the yields of the aromatic hydrocarbons were comparable to those with TiO2.