Synergistic effect and viscosity reduction mechanism of different biomass and extra-heavy oil in aquathermolysis

• Biomass can promote the aquathermolysis of extra-heavy oil. • Biomass is conducive to the increase of aromatic hydrocarbon components in extra-heavy oil during aquathermolysis. • Biomass has more advantages than water as H and O sources in aquathermolysis of extra-heavy oil. • The active hydroxyl group can capture free radicals generated in the process of aquathermolysis. Biomass is a “Carbon Neutral” type of green energy. It is a promising and practical concept to use biomass to improve the yield and quality of heavy oil. In this experiment, the effects of five biomass (Sawdust, Sesame oil cake residue, Straw, Sorghum distiller’s residue and Rapeseed oil cake residue) in aquathermolysis of Liaohe extra-heavy oil were studied. Elemental Analyzer (EA), H-Nuclear Magnetic Resonance ( 1 H NMR) and Gel Permeation Chromatograph (GPC) were used to study the changes of extra-heavy oil during aquathermolysis. Gas Chromatography-Mass Spectrometry (GC–MS) was used to analyze the composition of water phase. In addition, three model compounds (Microcrystalline Cellulose, Xylan and Lignin) were selected to study the upgrading mechanism of biomass in aquathermolysis of extra-heavy oil. Based on the experimental results, we believe that biomass has more advantages than water as H and O sources in the upgrading process of extra-heavy oil. However, the active hydroxyl group in the biomass reduces the upgrading efficiency of extra-heavy oil because it can capture the free radicals generated during aquathermolysis.