Estimação de parâmetros e análise do desempenho termodinâmico na hidrólise enzimática em batelada alimentada para a conversão de biomassa em glicose

Abstract

Among the steps necessary for the production of bioethanol, using lignocellulosic biomass, pre-treatment and enzymatic hydrolysis can be classified as the most important. In general, lignocellulosic biomass is composed of cellulose, hemicellulose and lignin. Lignin is organized in a complex and non-uniform way, promoting biomass recalcitrance. This characteristic hinders the enzymatic attack on cellulose for conversion into glucose, and, consequently, the production of biofuel. Performance in enzymatic hydrolysis is characterized by the yield and productivity of glucose, which depends on the composition and pre-treatment of lignocellulosic biomass, enzyme concentration, among other factors. Therefore, fed-batch enzymatic hydrolysis used in the conversion of biomass into biofuels was analyzed in this work. Due to its complexity, the mathematical description of this system, influenced by the composition of the biomass and the formation of inhibitors, is a challenge. To address this complexity, the study aims to model the process, estimating parameters to achieve high glucose concentrations in a bioreactor operating in fed-batch mode. Using thermodynamic properties, especially exergy analysis, we sought to evaluate the performance and sustainability of the process. Therefore, a study previously developed by Cavalcanti-Montaño et al. (2013). When considering the evaporation of the solvent from the reaction medium, the behavior of the profile for the volume predicted in this work was similar to the experimental volume obtained in the literature. Furthermore, based on parameter estimation, it was possible to obtain glucose concentration rates equal to 204.23 g.L-1 for an initial potential glucose concentration of 44 gglucose-potential.Lsolution-1 . The total exergy potential available to the system was 1,239.93 kJ, with 30% of this exergy being destroyed at the end of the operation. The system achieved an overall exergy efficiency of 70.04%, while the rational efficiency reached 37.33% at the end of the process. Furthermore, the process sustainability indicator (PSI) reached a value of 1.67 and the system achieved a thermodynamic sustainability value of 3.34. Therefore, the system demonstrated its thermodynamic sustainability, where the process sustainability index confirms a promising approach for fed-batch operation.