Elemental migration and characterization of products during hydrothermal liquefaction of cornstalk

Biofuel production from lignocellulosic biomass through hydrothermal liquefaction (HTL) is a promising direction. This study characterized the products and investigated the elemental migration during the HTL of cornstalk at seven different operation temperatures (210-375°C). The biocrude oil yield significantly increased from 7.04% (210°C) to 23.32% (290°C) as the temperature increased, and decreased to 21.07% when further increased to 375°C. A carbon recovery of 11.03-38.69%, and a hydrogen recovery of 7.77-25.61% were achieved in the biocrude oil. Hydrogen (27.87-70.94%) and nitrogen (74.56-81.76%) were effectively recovered in the aqueous phase. GC-MS, HPLC, TGA and FT-IR analysis indicated that major organic compounds in the biocrude oil were interestingly similar between 210°C and 270°C. The identified compounds included hydrocarbons, esters and carboxylic acid. The calculative yields of biocrude, hydrogen, methane and biochar reached 7.04-23.32, 0.07-0.29, 7.12-12.08 and 3.01-22.42t/100t cornstalks, respectively.