(496b) Glycerol As a Co-Solvent for Hydrothermal Liquefaction of Corn Stover

Hydrothermal liquefaction (HTL) is a thermochemical process capable of converting lignocellulosic biomass (LCB) such as woody biomass, forest/agriculture residue, switchgrass, and corn stover into value-added products. Depending upon the HTL processing conditions used, the distribution of products such as bio-oil, hydrochar, phenolics, C1-C3 carboxylic acids, and oxygenated hydrocarbons would vary. Typically, LCB is converted in a hot, pressurized water for a residence time of 1-2 hours at low to moderate operating temperatures as compared to the pyrolysis. These operating conditions result in low tar yield and high conversion efficiency. The use of glycerol is known to influence product distribution as well as the yield. In this study, HTL of corn stover was carried out at 250-300°C using glycerol as a co-solvent. Biomass to solvent/co-solvent (B:S) weight ratio was varied to study the effect on products yield and their distribution. The resulting liquid product (biocrude) after HTL was fully characterized by elemental analysis and gas-chromatography/mass-spectrometry (GC/MS). The solid product, hydrochar was recovered and characterized by elemental analysis, Brunauer-Emmett-Teller (BET) surface area analyzer and FTIR. The effect of glycerol on products yields and quality was evaluated compared with the products obtained in the absence of glycerol. Experimental results of HTL processing of corn stover in the presence of glycerol will be presented.