Avaliação do pré-tratamento do bagaço de cana-de-açúcar com glicerol

Abstract

Energy supply in the coming decades is one of the current concerns, as oil, a fossil and non-renewable source, has become scarce. In this sense, sugarcane bagasse has been presented as an important alternative for its potential in the generation of energy and the formation of products with high added value. The objective of this work was to carry out the kinetic study of glucose, xylose and arabinose formation from sugarcane bagasse pre-treated with glycerin. The pre-treatment experiment was carried out in an argon pressurized batch reactor at temperatures of 130, 170 and 210 ° C with a reaction time variation of 15.0 to 240.0 min, using 2.0 grams of biomass and glycerin concentration of 39% v / v. The concentrations of the sugars after the pretreatment steps were determined by high performance liquid chromatography (HPLC). The "in natura" and pre-treated bagasse were characterized according to moisture content, ash, elemental, thermogravimetric analysis, X-ray diffraction and calorific value. The kinetic study showed that the concentrations of all sugars were increasing with increases in time and temperature up to the experimental condition of 180 minutes and 210 oC. The rate constants of the pretreatment reactions increased with the increase in temperature and the values of the activation energies obtained for glucose, xylose and arabinose were 29.37; 11.06 and 15.55 kJ mol-1, respectively. The increase in temperature had a significant influence on the solubilization of sugarcane bagasse. Among the bagasse components, the hemicelluloses were the most affected by the pretreatment, with the highest solubilization of 77.5%. In general, sugarcane bagasse pretreated with glycerol showed an increase in carbon content and higher calorific value in relation to "in natura" biomass. The different events observed in the thermogravimetric analysis of bagasse evidenced the heterogeneity of the biomass. It was observed a decrease in the crystallinity index of the pre-treated bagasse that may be due to the disorganization of the crystalline regions of the cellulose. The results obtained showed the efficiency of the use of glycerol on the recalcitrance of bagasse and the possibility of its use in the obtaining of value-added products.