Xylose removal from lignocellulosic biomass via a twin-screw extruder: The effects of screw configurations and operating conditions

It was the objective of this study to evaluate the feasibility of separating xylose from lignocellulosic biomass (steam-exploded corncobs) in a co-rotating twin-screw extruder, through water addition and solid-liquid separation. Eight screw configuration profiles were evaluated to define the best performance on xylose recovery. Subsequently, operating conditions (barrel temperature, screw speed and water flow rate) were examined with respect to xylose recovery and specific mechanical energy consumption of the motor drive. It was found that liquid/solid separation highly depended on the position and spacing of reverse screw elements. For a given configuration the xylose recovery increased with increases in temperature and was only weakly correlated with the agitation rate. The xylose recovery went through a maximum when the flow rate of additional water was approximately 0.33 kg h−1 water per kg h−1 biomass feed rate. Furthermore, operating conditions influenced the specific mechanical energy consumption of the motor drive, allowing to minimize the amount of energy needed to obtain a prescribed xylose removal.