Termogravimetria aplicada para caracterização da biomassa

Abstract

Issues related to renewable energy have been increasingly addressed and discussed. In this context, biomass is an alternative for the generation of renewable and available energy. Its use, instead of fossil fuels, helps to reduce the environmental impact and the greenhouse effect. The aim of this study was to verify the influence of biomass components on their thermal degradation using thermogravimetry and to compare values for proximate analysis and for a heating schedule. The materials used were pine (Pinus elliottii) and eucalyptus (Eucalyptus Grandis x Eucalyptus Urophylla) woods and sugarcane bagasse (Saccharum officinarum). The raw materials were analyzed in 4 different treatments: in natura, material without extractives, holocellulose and lignin. The thermogravimetric analyzes were performed on the Perkin Elmer TGA device Pyris 1 TGA. The analyzes were carried out under a nitrogen atmosphere with a flow of 20 ml.min-1. The heating rate was 20 ° C.min-1 starting at 50 ° C to 900 ° C. Proximate analysis of the biomasses, the chemical composition of the materials and the high heating value (HHV) with and without extractives were calculated. It was observed that the presence of the extractives decreases the temperature of the beginning of the thermal degradation, and they are the first ones to be volatilized, besides diminishing the HHV. From the separated components of the biomass, it was observed that the polyses and cellulose, which composes holocellulose, begin their degradation before lignin, which presented a higher degradation temperature and a higher thermal stability.