Pirólise da borra de café: cinética química e operação em leito fixo

Abstract

For decades, fossil fuels have been the main responsible for the generation of energy in the world. However, due the destocking of fossil fuels and the concerns rising over the protection of the environment, the use of biomass appears as an alternative for power generation. The pyrolysis of biomass is a conversion process in which heat the polymer chains of the subcomponents of the biomass, cellulose, hemicellulose, lignin and extractives, are broken down in order to produce volatile compounds of lower molecular weight, forming coal fines, gases, volatile substances and the bio-oil, which have high calorific value and have had many applications in both the chemical industry and in power generation. Knowledge of aspects related to chemical kinetics, thermodynamics, phenomena of heat and mass transfer, in addition to the fluid dynamic behavior inside the reactor, is of fundamental importance for the design and optimization of the pyrolytic reactor, since the characteristics of quality of products and good understanding of the parameters affecting the process rely heavily on these aspects. The kinetics of pyrolysis of coffee grounds was investigated using experimental data of loss of mass by Thermogravimetry (TGA). For the characterization of the material, elemental analyses were undertaken, immediate, scanning electron microscopy (SEM) and infrared spectroscopy, in addition to the lignocellulosic composition. Was performed even the analysis of kinetic parameters of pyrolysis of coffee grounds, using the isoconversional methods, global reaction and parallel reactions model independent.