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 UMaineâs 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.
