Monday, May 4, 2009
5-52

Enzymatic hydrolysis of lignocellulosic biomass: modeling and simulation of CSTR’s in series

Arturo Gonzàlez Quiroga, Aline Carvalho da Costa, and Rubens Maciel Filho. Department of Chemical Processes, School of Chemical Engineering, State University of Campinas, Albert Einstein Avenue, 500, Campinas, 13081970, Brazil

Enzymatic hydrolysis of biomass has gained considerable interest in the past decades because it can provide glucose, which serves as a raw material for alcohol and other chemical products. The bioreactor in which enzymatic hydrolysis occurs is a logical focal point in pursuing cost reduction for ethanol production from lignocellulosic biomass. Considerable efforts have been focused on understanding the mechanism of heterogeneous and interfacial hydrolysis, but there are no major studies on the configuration and performance of bioreactors for enzymatic hydrolysis.

The purpose of this study is to model glucose production from lignocellulosic biomass in a well mixed and at steady state series of CSTRs with continuous substrate and enzyme addition. The kinetic model for enzymatic hydrolysis assumes a pseudo-homogeneous Michaelis-Menten mechanism. Glucose and cellobiose profiles during hydrolysis of delignified sugarcane bagasse are fitted to a kinetic model for an initial substrate concentration of 5% W/V.

Two case studies are considered: a series of n CSTRs of optimal volumes and a series of n CSTRs of equal volumes, both with and without recycle. The reaction of particulate biomass in a CSTR is considered equivalent to segregated micromixing with respect to the substrate and complete micromixing with respect to the aqueous phase and the conversion is predicted using a particle population model in conjunction with the batch kinetics. Finally, a discussion is made about other reaction systems and modes of operation with respect to enzyme and substrate in order to reach the practical realization of the technology.