(191a) Development of a Two-Stage Thermal Deoxygenation Process for Fuels and Chemicals from Biomass

Thermal DeOxygenation (TDO) is the thermal decomposition of mixed salts of levulinic and formic acids that can produce hydrocarbon oils at yields approaching 80% of theoretical. These acids can be sustainably produced in stoichiometric quantities by acid hydrolysis and dehydration (AHDH) of cellulose. The TDO reaction was scaled up to a 50 L semi-batch reactor to produce more than 20 L of oil for fractionation, blending and hydrotreating. The products were thus demonstrated as suitable blendstocks for gasoline, diesel, jet fuel, and fuel oils. While scale-up facilitated kilogram quantities of products for testing, the carbon loss to char increased from 8.5% at the bench scale to 48% at 50 L floor scale. Isothermal reaction experiments have identified two reaction regimes: 1) a low temperature addition-condensation regime that is diffusion-controlled and 2) a high temperature ketonic decarboxylation regime that is reaction-controlled. Through this understanding, a two stage reaction process has achieved yields in the floor scale reactor similar to early bench scale results. Current process development efforts involve testing equipment to move from semi-batch to continuous operations and scaling up the TDO process to match the output of UMaine’s one-ton-per-day AHDH pilot plant. The combined AHDH-TDO process has the potential to produce a suite of bio-based chemicals in addition to fuels, so additional results include techno-economic analyses which consider the potential for co-product revenue enhancement of renewable fuels.