Characterization of products obtained from hydrothermal liquefaction of biomass (Anchusa azurea) compared to other thermochemical conversion methods

In this study, biomass was converted into new products with catalyst (H3BO3, Na2CO3, Al2O3) and without catalyst at 300, 325, and 350 degrees C by the hydrothermal liquefaction method. The products obtained were analyzed by GC-MS, FT-IR, SEM, elemental analysis, and H-1 NMR methods. Based on the trials, the highest liquid product yield (total bio-oil) was determined as 29.69% in the trial without catalyst at 350 degrees C. The higher heating value (HHV) has been calculated by Dulong's formula, and the HHV values of all the (light bio-oil, heavy bio-oil, and solid residue) were determined to be higher than the HHV value of the feedstock. The highest HHV value was obtained from heavy bio-oil as 31.32MJ/kg with the catalyst at 350 degrees C. This HHV value is higher than the HHV value attained by the pyrolysis and supercritical liquefaction method. The products obtained generally consisted of monoaromatics, polyaromatics, oxygen compounds, and aliphatics. Based on the results of the elemental analysis, HHV values varying between 16.22 and 31.78MJ/kg were found for all products.