Análise físico-química e pirólise da fibra de coco e da casca de cebola

Abstract

Lignocellulosic biomass represents an abundant and low-cost source of raw material for the production of renewable energy and various materials. It is composed of a complex mixture of cellulose, hemicellulose, lignin, in addition to extracts and ashes. Pyrolysis is a thermochemical process for the exploration of biomass, in which its chemical decomposition occurs, by heat, in the absence of oxygen, producing biooil, bio-gas and bio-char. Thus, the objective of this work was to perform the chemical and physical characterization of coconut fiber and onion peel and to study a pyrolysis of both as biomasses by analyzing the effect of pyrolytic temperature and the addition of magnesium chloride (MgCl2) on pyrolytic products. The physical and composite properties of coconut fiber and onion skin were evaluated through particle size distribution, particle shape analysis, density, in addition to analyzes: immediate, lignocellulosic composition, Infra-Red Spectroscopy with Fourier Transform (FTIR) and thermogravimetric. The kinetics of thermal degradation of the biomasses were evaluated using the Global Reaction Reparametrized model from the experimental data of the thermogravimetric analyzes for the heating rates of 20, 30, 40 and 50 °C.min-1 . Each biomass was subjected to six fixed bed pyrolysis experiments through a 2² experimental design with two replicates at the central point, in order to evaluate the pyrolysis temperature effects (350, 400 and 450 °C) and the addition of MgCl2 (0, 5 and 10%) in the yield of liquid products, bio-coal and bio-gas. For both as biomasses it was observed that the yield of liquid products is favored by the increase in the temperature of pyrolysis and lowering of the salt; for bio-char, it is observed that the higher the concentration of MgCl2 and the lower the pyrolysis temperature, the greater its yield; as for bio-gas, the highest yield observed for high rates and low lows of salt. By analyzing the FTIR spectra of the pyrolytic products of the biomasses obtained with the main structures present in the aqueous phase, the O-H elongation, aromatic bonds C = C and C-H; in the bio-chars, the presence of O-H elongations, CHn, C = C aromatic bonds, CH2, C-O, C-O-C and C-H aromatics was identified.