Identifying and Modeling Interactions between Biomass Components during Hydrothermal Liquefaction in Sub-, Near-, and Supercritical Water

We conducted experiments for the hydrothermal liquefaction (HTL) of binary mixtures of biomass components at 300, 350, and 425 °C and then developed a component-additivity model that accounts for interactions among biomass components during HTL and predicts the oil yields for processing biomass mixtures in sub-, near-, and supercritical water. The experimental work provided new insights about the interactions between different biomass components during HTL. Specifically, the interaction and extent of synergy between soy protein and cellulose was a function of the relative amounts of the two materials. Moreover, alkaline lignin has a stronger synergistic effect when processed with cellulose and starch, whereas dealkaline lignin has a stronger synergistic effect with stearic acid. These differences could not be attributed solely to the influence of pH, so there must be other factors that influence interactions of lignin with other biomass components during HTL. The model predicted 70% of the 141 literature bio-oil yields considered to within 10 wt % and performed better by this metric than did prior component-additivity models. Parameterizing the model at different temperatures and including a composition-dependent interaction between cellulose and protein are at the heart of this improvement.