Synergistic mechanism of enhanced biocrude production during hydrothermal co-liquefaction of biomass model components: A molecular dynamics simulation

Abstract

Hydrothermal co-liquefaction is a desirable technology for biocrude production from various biomass feedstocks, however, the insight into the mechanism of chemical reactions between biomass model components remains a huge challenge. To address this challenge, a detailed synergistic mechanism between model components was proposed based on molecular dynamics simulations for hydrothermal liquefaction (HTL) of cellulose, hemicellulose, lignin, lipid, and their mixtures. During the HTL process, the generation of aqueous phase products from cellulose and hemicellulose, polycyclic aromatic hydrocarbons from lignin, as well as undepolymerized macromolecules and carbon deposits from lipid hindered biocrude production from each component. As expected, synergistic interactions occurred between model components and enhanced biocrude produced from each component at a relatively mild HTL condition. Impressively, synergistic interactions were related to the transmission of reactive –OH groups between different biomolecules with the assistance of H2O molecules at transcritical states. By considering the interactions, a new and more versatile biocrude yield prediction model was developed based on biochemical compositions of feedstocks and reaction temperature. This work will provide new insight into potential interactions between biomass components and give a theoretical basis for feedstock “designing” in HTL of biomass wastes.