Catalytic Pyrolysis Vapor Upgrading of Corncob into Furans over Pyrolysis-Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry: Significance of Catalyst and Temperature

Analytical pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GCxGC/MS) was employed for the on-line analysis of catalytic pyrolysis products distribution and furans selectivity of corncob. Different catalysts (TiO2, ZrO2, MCM-41 and activated carbon (AC)) and catalytic temperature (350 degrees C, 400 degrees C, 450 degrees C and 500 degrees C) were investigated. The catalysts were subjected to several characterization methods, including temperature programmed decomposition of ammonia (NH3-TPD) and N-2 adsorption-desorption, to investigate the effects of physical-chemical properties of the catalysts on products distribution and furans selectivity. The experiment results showed that a lower catalytic temperature (<= 400 degrees C) was conductive to form furans and higher catalytic temperature (>= 450 degrees C) was promoted hydrocarbons formation, among the four catalysts. The AC catalyst gave higher furans relative peak area (54.48%) than other catalysts (31.24% similar to 41.99%). And higher total acidity (weak acidity) of AC was favored for the formation of furfural and furan, 2-methyl- at 350 degrees C. Moreover, AC had the great thermal stability, and the catalyst recycling tests showed that the prepared AC can be reused for five times in furan-rich bio-oil production. After cycle, the relative peak area of furans also maintained above 40%. In addition, furan, 2-methyl- always maintained a high relative peak area (8%). It was expected that four type catalysts can be widely used for biomass catalytic conversion to produce furans processes at low catalytic temperature, especially the AC.