Thermal characterization of agro-industrial waste for its use in energy valorization processes

Abstract

[EN] The aim of this work is to define, develop and evaluate a methodology for an improved and more sustainable management of waste, in particular, agricultural residues, turning them into a new source of energy and added-value products. Specific attention is paid to the use of cotton seed (CS) for energy generation. The recovery of energy was carried out through the pyrolysis of this biomass in a fixed bed reactor. An initial definition of the main physico-chemical and thermal properties of the feed was performed. The design and operational parameters of the reactor were set according to the characteristics of the biomass. The thermo-chemical process of pyrolysis was simulated in the first stage by multi-rate linear non-isothermal thermogravimetric (TGA) experiments using argon (Ar) as carrier gas. The thermogravimetric analysis is a widely used technique to assess the thermal stability and decomposition kinetics of biomass. From the kinetic analysis, valuable parameters related to the thermo-chemical process were obtained, such as the activation energy and the pre-exponential factor, both highly dependent on the temperature of reaction. Furthermore, the composition of the raw material was also provided by thermal studies, through the quantification of the different processes of mass loss observed during the heating process. The results were obtained from the TGA measurements, by applying a kinetic methodology based on the combination of the Friedman, Flynn¿Wall¿Ozawa, Kissinger¿Akahira¿Sunose iso-conversional methods and the use of Master Plots permitted to describe mathematically the thermochemical reactions. These results will help define the further use of CS as feedstock in energy recovery processes.