Comparative study of conventional and microwave-assisted liquefaction of corn stover in ethylene glycol

A comparative study on conventional and microwave-assisted liquefaction of corn stover has been carried out using ethylene glycol (EG) as liquefacient and sulfuric acid as catalyst. Microwave dramatically increased the liquefaction extent and rate compared to conventional heating. The liquefied products and residues in both methods have been investigated using gel permeation chromatography (GPC), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). The GPC results show that the molecular weight of liquefied products with conventional heating is significantly greater than those of microwave-assisted liquefaction. The FTIR spectra indicate that there are significant differences in the hydroxyl and carbonyl group contents in the liquefied products with the two methods. The residue from microwave-assisted liquefaction mainly consisted of mineral matter. Many granules appeared on the surface of microwave liquefied residue according to SEM observation.

► Microwave dramatically increased the liquefaction extent and rate compared to conventional heating.
► The molecular weight of liquefied products with conventional heating is significantly greater than those of microwave-assisted liquefaction.
► There are significant differences in the hydroxyl and carbonyl group contents in the liquefied products with the two methods.
► The residue from microwave-assisted liquefaction mainly consisted of mineral matter.