Hydrothermal extraction of hemicellulose: from lab to pilot scale

Abstract

A flow-through reactor for hemicelluloses extraction with hot pressurized water was scaled with a factor of 73. System performance was evaluated by comparing the temperature profile, extraction yield and kinetics of the two systems, performing experiments at 160 and 170 °C, 11 barg for 90 min, using catalpa wood as raw material. Hemicellulose yields were 33.9% and 38.8% (lab scale 160 °C and 170 °C) and 35.7% and 41.7% (pilot scale 160 °C and 170 °C). The pilot reactor was upgraded by designing a manifold system capable to provide samples with different liquid residence time during the same experiment. Tests at 140, 150, 160 and 170 °C were carried for 90 min. Increasing yields (9.3–40.6%) and decreasing molecular weights (4078–1417 Da) were obtained at increasing the temperature. Biomass/water ratio of 1/27 gave total average concentration of xylose of 0.4 g/L (140 °C) to 1.8 g/L (170 °C).