Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
KINETIC PARAMETERS AND COMBUSTION THERMAL BEHAVIOR OF AÇAÍ FIBROUS SEED BY THERMOGRAVIMETRIC ANALYSIS
Submission Author:
Fernando Henrique de Barbosa dos Santos , PA
Co-Authors:
Fernando Henrique de Barbosa dos Santos, Alan Carneiro, Ana Paula Mattos, Danielle R S Guerra, Manoel Fernandes Martins Nogueira
Presenter: Fernando Henrique de Barbosa dos Santos
doi://10.26678/ABCM.COBEM2023.COB2023-2146
Abstract
Açaí fruit production in 2019 reached about 1.4 million tons in Pará, of which about 70% is composed of the so-called fibrous seed. The importance of the fruit in the Amazon region makes the fibrous seed waste a potential renewable fuel, mainly when applied in co-combustion processes with coal. For such an application, it is necessary to know the thermal behavior of the residue during combustion by kinetic parameters and mass loss curves so that adjustments can be made to energy conversion equipment. This work aims to evaluate the combustion kinetics of the fibrous seed waste by thermogravimetric analysis (TGA) and Arrhenius parameters obtained by the Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. Samples of bituminous coal and açai seed with fiber and without fiber were heated from 298 to 1073 K in an O2 atmosphere at 40 ml.min-1 at three heating rates: 10, 20, and 30 K.min-1. The mass loss (TG) and mass loss rate (DTG) curves allowed the identification of two stages of combustion. The first was related to the release of volatiles and the second to char oxidation. The peaks of higher mass loss rate for the first stage vary between 554-569 K, while the second stage varies between 676-729 K. The results obtained by the KAS and FWO methods showed slight variation between each other. The activation energy varies between 119.1-168.7 kJ.kmol-1 (coal), 186.1-301.5 kJ.kmol-1 (seed with fiber) and 170.6-1161.8 kJ.kmol-1 (seed without fiber). The variation of the activation energy indicates that the reaction mechanism for the burning of açaí is not the same for the entire combustion process, dependent on the degree of conversion, unlike coal whose values show slight variation as a function of conversion degree. The açaí seed presents high peaks of mass loss rate during the release of volatiles, which suggests the formation of more intense flames during the initial burning stages in comparison to coal, which has no related peaks related to the release of volatiles.
Keywords
Biomass, Açaí seed, isoconversional methods, Combustion, Thermogravimetry
