Kinetic studies of two-stage sulphuric acid hydrolysis of sugarcane bagasse

Abstract

The present paper reports the two-stage hydrolysis of sugarcane bagasse to produce monomer sugars by using dilute and concentrated sulphuric acid. About 88% of the sugars present in bagasse could be recovered with a little formation of toxic compounds such as furfural/HMF. The sugar concentration in the first-stage of hydrolysis was obtained as xylose-rich solution of 49.7 g l−1 using 8% acid concentration at 100 °C and a solid to liquid ratio of 1:4, whereas, with the same solid to liquid ratio of 1:4, 73.4 g l−1 glucose-rich solution was obtained in the second-stage of hydrolysis by using 40% acid concentration at 80 °C. The acid hydrolysis of bagasse could be described by a first-order, two-step consecutive reaction model, where the polysaccharides first decompose into monomers through hydrolysis, and thereafter, decompose into various products in the second step. The proposed kinetic model correlates the experimental data satisfactorily.