Rheology Characterization of Lignocellulose Feedstock During High Solids Content Pretreatment and Hydrolysis

Abstract

The accurate rheological properties of lignocellulose feedstock are crucial basics on designing industrial scale bioreactors by CFD model. Tendency of lignocellulose refining is to acquire more product yield at high solids loading and reduces the cost of subsequent process. This chapter reviewed the physical and rheological properties of raw material and the incompletely and completely pretreated material and hydrolysis slurry based on the dry acid pretreatment and high solids containing enzymatic hydrolysis. The apparent viscosity of pretreated lignocellulose feedstock was significantly related to the efficiency of pretreatment and consequent hydrolysis. The chapter firstly analyzed the rheology evolution during the dry acid pretreatment under extremely high solids ratio and established the basis for scaling up of pretreatment reactor. Due to the disturbance of abundant fiber particles, conventional rheometers or viscometers were impracticable to high lignocellulose solids system. A new on-site method using the torque meter equipped on hydrolysis reactor is suggested for accurate rheological property measurement. The measured torque data were transformed into the apparent viscosity and then the rheological parameters of the power law model after correlation. Based on these measured rheological properties of lignocellulose, this chapter used CFD model to simulate the power consumption and mixing performance of pretreatment reactor and hydrolysis reactor and designed optimal structure of large-scale bioreactors of high solids content pretreatment and hydrolysis system.