Surfactant Assisted Hydrothermal Liquefaction of Corn Stover for Hydrochar and Oil Production

B. Maddipudi, K. Huynh, Z. Fickbohm, A. Shende, G. Bauer, R. Shende
South Dakota School of Mines,
United States

Keywords: hydrothermal, corn stover, surfactant, hydrochar, HBO


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 in the presence of surfactants. HTL processing conditions such as temperature, initial nitrogen pressure, biomass to water ratio, and surfactant concentration were varied, and the products generated were analyzed. 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 process resulted in a product gas, aqueous biocrude, heavy bio-oil (HBO) and hydrochar. The biocrude was characterized by 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. Hydrochar can be activated and used for energy storage application as a sustainable electrode material whereas HBO can be upgraded to sustainable aviation fuel, ASPEN plus modeling was performed to scale-up HTL biomass processing at 1 tpd scale. Technology concept, processing, characterization of products, and ASPEN modeling results will be presented.