Investigação das propriedades físico-químicas, térmicas e energéticas de biomassa de tucumã torrefadas

Abstract

The increasing demand for renewable energy sources and the need to manage agricultural waste have driven research on the torrefaction of tucuma endocarp (seed kernel), an abundant residue in the Amazon, as a means of sustainable energy production. The endocarp, a lignocellulosic residue from tucuma, presents challenges due to its high moisture content and low resistance to biodegradation, limiting its direct use as a biofuel. This study explored torrefaction as a pretreatment to enhance the properties of tucumã endocarp for energy applications, such as moisture reduction and increased energy density. The biomass was characterized, revealing lignin (56.49%), holocellulose (51.78%), and extractives (0.66%) contents. Torrefaction was conducted at different temperatures (210, 240, 270, and 310°C) for 30 minutes, and the samples were analyzed using thermogravimetric techniques (TG/DTG) and infrared spectroscopy (FTIR). The results demonstrated that torrefaction reduced moisture content, increased fixed carbon content, and enhanced the biomass's higher heating value (HHV). A torrefaction temperature of 240°C was considered optimal, yielding a mass retention of 79% and an energy yield of 81.50%. TG/DTG analysis revealed hemicellulose decomposition at lower temperatures and greater thermal stability of lignin. FTIR analysis confirmed the reduction of oxygen-containing functional groups and cellulose depolymerization at higher temperatures. Additionally, the pyrolysis kinetics of torrefied and non-torrefied samples were studied using the Flynn-Wall-Ozawa (FWO) and Vyazovkin (VYZ) models. Biomass torrefied at 240°C exhibited higher usable internal energy, indicating its potential as a renewable energy source. This study concludes that torrefaction is an effective method to improve the properties of tucuma endocarp, making it a promising bioenergy source that contributes to energy sustainability and the valorization of agricultural residues in the Amazon.