Effects of SiO2/Al2O3 ratio and Fe loading rate of Fe-modified ZSM-5 on selection of aromatics and kinetics of corn stalk catalytic pyrolysis

Abstract

To solve the problems of complicated compounds and high oxygen content in pyrolysis bio-oil, Fe-modified ZSM-5 catalysts (wet-impregnation, SiO2/Al2O3 ratio: 30, 40, 50 and 60, Fe loading rate: 2 wt%, 4 wt%, 6 wt%, and 8 wt%) were prepared and employed to improve the selection of aromatics using Py-GC/MS and to investigate the kinetics of corn stalk catalytic pyrolysis by TGA tests and Friedman isoconversional kinetics method. Results revealed that the highest yields of aromatics were obtained using Fe/ZSM-5 with a Si/Al ratio of 40 and Fe loading rate of 4 wt%, which was 38.28%. The existence of Fe on ZSM-5 leads to an increase of monocyclic aromatics compared with parent ZSM-5. Effective activation energies for the catalytic pyrolysis of corn stalk over Fe(4)/ZSM-5(40) were decreased to 146.47–299.63 kJ mol−1 compared with non-catalyst. This work can provide a reference for future studies on biomass catalytic pyrolysis.