The first phase of this project evaluated the reaction pathways for biomass feedstock in the presence of various cosolvents including acetone, methanol, CO2, and water using a 1 liter (di: 7.6cm, l: 23.1cm) high pressure batch reactor. Additionally, the effect of temperature on the extent of the reaction was assessed at 200 to 350 oC. In both instances biomass conversion rates compared to the starting material ranged from 70 to 90 %, with the remaining portion being the unreacted fraction and lignin. The resulting products consisted of complex chemical fractions: organic acids, organic ester derivatives, sugars, sugar-alcohols, thermal degradation products and more. Although the impact of using various cosolvents was noticeable at lower temperatures, at higher temperatures the extent thermal degradation products increased due to longer heating times to reach the target temperature (2 to 8 hrs.). Despite the challenges with longer residence time when using the batch reactor, results from this study gave an important understanding of the reaction behavior and interaction of the solvent and biomass.
To have better control of the reaction extent at pilot scale, a flow reactor was assembled. The system consisted of a 250 ml/min slurry pump with reactor chamber that is 212 cm longer by 3 cm diameter, a maximum system working pressure up to 69 Mpa, electrical heating jackets and a condenser. Biomass slurry of 5 to 10% was fed into the reactor at varying temperatures from 200 to 350 oC and at residence times of 5 to 30 minutes. Analysis results from the flow reactor study will be main focus for this discussion.