Impact of a pressurized hot water treatment on the quality of bio-oil produced from aspen

Although PHWT does not seem to influence the bio-oil yield, which remains around 56% for both untreated and pre-treated wood, it does improve its quality. The main effect of pre-treatment is the lower water content of the oil obtained from pre-treated wood, which is thus meeting the requirements of ASTM D7544 Standard. Moreover, PHWT appeared to favor the levoglucosan production and to decrease the syringol derivatives content of the bio-oil. The elementary composition revealed an increase of the C/O ratio when the biomass was pre-treated. This is in agreement with the heating value of bio-oil from pre-treated biomass which was found to be higher than that of bio-oil from untreated biomass.