Kinetic Modeling of Hemicellulose Hydrolysis from Triticale Straw in a Pressurized Low Polarity Water Flow-Through Reactor

Two classic and one modified kinetic models were used to study the hydrolysis of triticale straw using pressurized low-polarity water (PLPW) in a flow-through reactor. Results indicated that for these experiments hemicellulose did not follow a biphasic reaction pathway. High yields of 72% were achieved at 170 °C, but these decreased to 60% at 150 °C and only 13% at 130 °C. The kinetics were controlled more by increases in temperature than flow rate in the reactor. Increases in flow rate reduced the overall hemicellulose yields but increased the portion extracted as oligomers. The kinetic rate constants when plotted as an Arrhenius-type temperature relationship displayed a dependency with flow rate. Curvature in the Arrhenius plots of the kinetic rate constants was due to differences in acetic acid formation with temperature. A modified monophasic kinetic model which incorporated reactor geometry and fluid flow was successful at modeling the yield of xylo-oligomers and monomers in PLPW.