Pilot scale steam explosion and diluted sulfuric acid pretreatments: Comparative study aiming the sugarcane bagasse saccharification

Abstract

Pilot-scale pretreatments, namely steam explosion (SE) and diluted sulfuric acid (SA), of sugarcane bagasse followed by alkaline delignification (SED and SAD) were explored. Most of the pentosan (97% and 93%), and the lignin content were solubilized during pretreatment and delignification process for SE and SA, respectively. SE demanded 50% more NaOH in the delignification step than SA, due to ion exchange nature of cellulignin. SE is more advantageous than SAD due to better unpacking of the fibers, allowing a higher cellulose conversion (90%) in relation to SAD pulps (79%). Cellulose conversion has a direct dependence with cellulose, hemicellulose and residual lignin. A composition factor (H*L/CC) and enzymatic kinetics were evaluated for the in natura, pretreated and pretreated and delignified materials. The Langmuir isothermal- type equation expressed a factor related to the capacity of hydrolysis, where SE pointed a material with similar hydrolysis capability of the combined SAD pretreatment.