Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
NUMERICAL MODELING OF RESIDUAL WOODY BIOMASS TORREFACTION
Submission Author:
Jesús David Rhenals Julio , Córdoba , Brazil
Co-Authors:
Jesús David Rhenals Julio, Juan Pablo Arteaga Ramos, Carlos Manuel Romero Luna, Ivonete Ávila
Presenter: Juan Pablo Arteaga Ramos
doi://10.26678/ABCM.ENCIT2022.CIT22-0624
Abstract
In the global context, biomass has been gaining relevance as a renewable energy source, this is due to its high availability in some regions and its direct relationship with sustainable development, however, the direct application of biomass as fuel in combustion and gasification systems faces great challenges due to some properties of biomass, However, these drawbacks can be addressed by means of the torrefaction process, which increases the energy density of biomass by concentrating the fixed carbon present and also reduces the compatibility with water by thermally degrading the hemicellulose. In this work, a model of dry, non-oxidative torrefaction of pine forest residues was developed in order to identify the most appropriate temperature and residence time parameters for this process, using a two-stage species transport model with Arrhenius kinetics coupled to a heat transfer model in cylinders, The model was solved using a finite difference scheme, analyzing the temperature distribution over time and the impact of temperature and residence time on biomass composition, mass yield, heating value and energy yield. The results show that the highest heating value was 21 MJ/kg and was reached at a temperature of 525 K, however, the highest energy yield was obtained at 500 K, since at this temperature the mass loss was lower. It was also found that, for particle diameters of 10 mm, after 35 min, the temperature distribution is approximately constant. On the other hand, it was observed that, at a temperature of 500 K, the formation biomass composition is dominated by natural biomass and the intermediate solid, while the fraction of carbon present is very small. As for the composition of volatiles, it was found that light volatiles were emitted in higher amount than secondary volatiles. Finally, the results of the calorific value obtained in the model were compared with experimental results from the literature, finding that the percentage of error calculated was in the range of 1-5%, so it is concluded that the two-phase model with Arrhenius kinetics and one-dimensional heat transfer provides reliable results in terms of heating value.
Keywords
Torrefaction, Wood, energy, Biomass
