Direct liquefaction of eucalyptus wood using solvent of alkaline aqueous solution mixed with light oil

Abstract

Arid land afforestation are attracting as a way to combat global warming. The authors considered the use of afforestation trees as biomass for petroleum alternative liquid fuels. The tendency of liquefaction of woody biomass differs depending on the solvent. The previous study reported that a high yield of liquefied oil with high polarity can be attained by using an alkaline aqueous solution as a solvent. However, liquefied oil with high polarity cannot be used as a light oil mixed fuel. On the other hand, another previous study reported that by the use of light oil as a solvent, the homogeneous liquefied oil is obtained. However, the liquefied oil yield is low. Therefore, the authors thought that a mixed solvent of light oil and alkaline aqueous solution could be used to obtain low-polarity liquid fuel in high yield. This study aimed to clarify the liquefaction mechanism of woody biomass under mixed solvents. First, it was confirmed that the use of mixed solvents gave higher yields of low-polarity liquefied oil than the use of light oil solvents. Next, the reaction temperature was changed, and it was found that cellulose was liquefied at 250°C, lignin was decomposed at 300°C, and at 350°C, lignin decomposed products and liquefied oil combined to produce a residue. Finally, liquefaction was performed by changing the temperature holding time, and it was found that hydrogen produced by the water gas shift reaction was donated to the biomass decomposed product at the holding time of 60 min.