Extraction of Hemicelluloses from Poplar Using a Twin-Screw Reactor: Influence of the Main Factors

Abstract

Fractionation of poplar wood chips, Populus tremuloides, was carried out using a modified Clextral BC 45 twin-screw reactor. The effect of the main factors: temperature (40-70°C), liquid flow rate (17.5-47.5 kg.h−1), NaOH concentration (3-7% w/w), solid flow rate (1.5-4.5 kg.h−1), and screw rotation speed (100-250 rpm), on the solubilization of the hemicelluloses was studied according to the Doehlert’s method for the design of experiments. The main results indicate that the reactor behaves either as a batch reactor when the sodium hydroxide concentration in the extracting solution is above 5%: yield of the solubilized hemicelluloses increases as the NaOH concentration is increased, or behaves as a Thermo-Mechano-Chemical (TMC) reactor when this concentration is under 4%: the yield of solubilized hemicelluloses increases as the NaOH concentration is reduced.