Understanding the mechanism of cornstalk liquefaction in water/ethanol mixtures through Py-GC/MS analysis of the solid residues

Abstract

Few investigations have been made to apply thermal analysis methods on solid residue analysis to understand biomass liquefaction mechanistic information. To investigate the mechanism of cornstalk liquefaction in water/ethanol mixtures, the solid residues remaining after the liquefaction process were characterized by thermogravimetric analysis (TGA) and analytical pyrolysis (Py-GC/MS). Pyrolysis temperature and liquefaction temperature have synergetic effects on the distributions and yields of various chemical groups during the pyrolysis process. The thermal stabilities of the solid residues remaining after the cornstalk liquefaction process increased with the increase of liquefaction temperature. Compared with raw cornstalk pyrolysis, the proportions of total phenol compounds from solid residue pyrolysis at 400 °C, 500 °C and 600 °C were reduced. The volatilized compounds identified by Py-GC/MS analysis of solid residues and cornstalks displayed significant variability in the peak area and composition distribution. These changes reflect different mechanistic information during the biomass liquefaction process. These results indicate that analytical pyrolysis of the solid residues remaining after biomass liquefaction in water/ethanol mixtures could provide new information about the mechanism of the liquefaction process.