(516c) Surfactant Assisted Catalytic Hydrothermal Liquefaction (CHTL) of Corn Stover for Fuels and Value-Added Products

Worldwide, as corn crop yield is more than 1 bty, significant amount of corn stover is available for bioprocessing. In this study, we investigated hydrothermal liquefaction (HTL) of corn stover at 225°C to 300 °C and 800- 1300 psi (system autogenous pressure) using different catalytic materials and surfactants. Catalytic hydrothermal liquefaction (CHTL) of corn stover and derived unhydrolyzed solids (UHS) was performed at different processing conditions of temperature, initial nitrogen pressure, biomass to water ratio, and catalyst loading. Presence of a surfactant is known to change the wettability, reduce the hydrophilicity and increase interfacial surface area, which can influence characteristics of hydrochar as well as distribution of liquified products, mainly the C1-C3 carboxylic acids. HTL processing resulted in product gas, aqueous biocrude, heavy bio-oil (HBO) and hydrochar. The aqueous biocrude was characterized by the TOC analyzer and gas-chromatography mass spectrometry (GC-MS) to understand extent of liquefied carbon and oxygenated hydrocarbons, respectively. Both hydrochar and HBO were analyzed by the elemental analyzer and HHVs were estimated based on C, H, N and O content. Liquid - liquid extraction methodology was developed to separate phenol/substituted phenols from aqueous biocrude. HTL processing, separation methodologies, process engineering aspects and scale-up strategies will be presented for the conversion of corn stover and UHS into value-added products.