Hydrothermal Liquefaction of Wheat Straw in Sub-critical Water/Ethanol with Ionic Liquid for Bio-oil Production

Hydrothermal liquefaction of wheat straw in sub-critical water with ionic liquid was investigated in an autoclave. The product distribution at different temperatures and pressures was studied. The liquid oil and the residuals were tested by 1H NMR, FTIR and SEM techniques. The results indicated that under the same conditions, the oil yield from liquefaction of wheat straw in water/ethanol was higher than that in sub-critical water. The result also showed that under the investigated conditions, adding 1-butyl-3-methylimidazolium chloride([Bmim]Cl) could increase the total conversion and gas yield, while at the same time the yield of n-hexane insoluble fraction and the tetrahydrofuran soluble fraction was reduced. Moreover, the results also showed that upon adding [Bmim]Cl the contents of the aliphatic hydrogen and phenols in liquid oil also increased along with improved oil quality.