Avaliação das propriedades energéticas do bagaço de cana-de-açúcar in natura e torrefado durante o armazenamento em uma usina de etanol

Abstract

The commercialization of energy by the sugar and alcohol sector is becoming more and more prominent in the Brazilian electricity matrix, and its presence as a product in the industry grows every year. A large part of this energy is generated from the burning of bagasse resulting from sugarcane milling, and the surplus is sent to storage yards without adequate technique or planning. As a result, millions of tons of bagasse are degraded in storage, affecting its characteristics, especially energy ones. In order to avoid this degradation and increase the calorific value of the bagasse, pre-treatments such as roasting are studied. This work aims to monitor and compare the variations in the energy properties of fresh and roasted sugarcane bagasse over the storage period. The research methods involve physical-chemical and thermal characterizations of fresh and roasted bagasse samples during storage. The material and methods are based on the physical-chemical and thermal characterizations of fresh and roasted bagasse samples during storage. The results show a courtyard with different dimensions and ambient temperatures, as well as the ash values, volatile material, fixed carbon and the moisture content, which ranged from 15.05 to 79.90% and was influenced by the particle size of the biomass of up to 43%. The calorific value of the bagasse from the mat ranged from 17.46 ± 0.19 to 19.37 ± 1.98 MJ.kg-1, very similar to that found in the stockyard from 17.50 ± 0.33 to 19.62 ± 0.73 MJ.kg-1. The roasted bagasse, on the other hand, was worked with 3 different roasting temperatures: 200, 250 and 300 ºC, allowing an increase in the higher calorific value of up to 52.62%. However, in storage there was an increase in this humidity, in addition to the presence of inorganic material from the yard, which lowered the higher calorific value by 49.56%. In thermogravimetric analyses, the thermal degradation of hemicellulose, cellulose and lignin are very evident, mainly in roasted bagasse. In combustion, the physical-chemical characteristics influenced the temperature peaks and biomass degradation, where the oxidative atmosphere was more oxidizing in the samples. Thus, this study emphasizes the importance of the characteristics of bagasse in natura for the storage process, in addition to contributing to the quality of the roasted bagasse, whose effectiveness of PCS is attenuated by temperature and roasting time, also suffering climatic and environmental influences. in which it is stored.