Thermal behavior and production distributions of organosolv-phase oxidization pretreatment of biomass coupled with fast pyrolysis

Abstract

Organosolv-phase oxidization pretreatment of corncob (OOPC) at ambient pressure and temperature coupled with fast pyrolysis was first performed. The effects of organosolv/water phase with/without oxidation, Fe2+ contents, H2O2 concentrations, pyrolytic behavior, and kinetic analysis on the distributions of pyrolytic products were investigated. The yields of higher oxygen-containing components such as anhydrosugars were obtained from fast pyrolysis of OOPC in comparison with raw, organosolv-phase, and water-phase oxidization pretreated corncobs. With the increase Fe2+ contents and H2O2 concentrations during organosolv-phase oxidization pretreatment, the O/C ratios (0.35–0.51), levoglucosan yield (2.2–160.2 mg/g), and relative content of anhydrosugars (5.5–72.9 %) were remarkably improved whereas the yield of pyrolytic chars (21.4–13.4 %) and average E values (65.5–50.4 kJ/mol) significantly decreased compared to raw sample. The pyrolysis products of OOPC were remarkably transformed from low-molecular compounds of raw sample to high-molecular compounds. The higher Fe2+ contents and H2O2 concentrations were conductive to the elimination of biomass resistant and the formation of oxygen-rich fractions mainly consisting of considerable amounts of C–O, O–CO, and –OH bonds due to the effective removal of carbon-rich fractions (C–C bonds), which were responsible for the increase in anhydrosugars.