Liquefaction reaction process and mechanism of cornstalk in sub/super critical cyclohexane

The effects of reaction temperature, cyclohexane quantity and reaction time on the liquefaction of cornstalk in sub- and super-critical cyclohexane were investigated by using a batch type reactor. Experiments were carried out over the temperature range of 260-320℃, and pressure range of 2-4.5 MPa. The results showed that the reaction temperature, cyclohexane quantity and reaction time had significant influences on the pyrolysis products. With the temperature increasing from 260 to 320℃, the residue and heavy oil yields decreased by 4.9% and 3.34% respectively. A low residue yields reached to 36.54% with 40 mL cyclohexane at 310℃ for 20 min. The gas and light oil products increased while the residue decreased with the reaction time from 0 to 40 min. The GC/MS measurements for the light oil and heavy oil revealed that the cellulose, hemicellulose and lignin in cornstalk were liquefied in sub/super critical cyclohexane. The components of heave oil were mainly phenol and its derivatives, and pyranoid derivatives and organic acids were dominant in the light oil. Meanwhile the research showed that cyclohexane played the role of hydrogen reforming and a secondary reaction existed in the liquefaction process. The lignin liquefaction reaction paths in sub- and super-critical cyclohexane and the liquefaction reaction network were built based on the results.