Encontro de Energia no Meio Rural

Abstract

FRANCA, Geraldo Augusto Campolina and CAMPOS, Marcos Bandeira. Análise teórica e experimental do resfriamento de carvão vegetal em forno retangular. In Procedings of the 4th Encontro de Energia no Meio Rural, 2002, Campinas (SP) [online]. 2002 [cited 24 April 2024]. Available from: <http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022002000100017&lng=en&nrm=iso> .

This work presents the results of a numerical simulation of a bidimensional mathematical model which represents the natural colling process of a packed bed of charcoal inside a rectangular industrial kiln for wood carbonization, from V&M Florestal (Paraopeba/MG - Brazil). The purpose was to understand the significant mechanisms of heat exchange, so that future improvements can be implemented, such as reducing the period of cooling. The simulation was performed by a software designed in TURBO PASCAL language and the numerical method chosen was the Finite Difference Method (FDM) with implicit formulation. Thermophysical properties have been updated with the value of the temperature at each time. No fluid flow was considered inside the kiln by the use of an effective thermal conductivity for the bed. The effect of radiation among the particles and among the internal surfaces of the kiln was considered. The theoretical results were compared with the experimental data obtained by thermocouples. The validation of the model has let it be extended to the study of other conditions, like the effect of a reduction of the thickness of the walls and ceiling and the effect of the wind velocity outside the kiln. The study has indicated that the velocity of the wind and a reduction of the thickness of the ceiling have a small influence over the period of cooling, on contrary of what has been observed with a reduction at the thickness of the walls.

Keywords : Carvão vegetal; resfriamento; forno; leito poroso.