Secagem de sólidos via ciclones: modelagem e simulação.

Abstract

In recent years, cyclones have been used as a modern drying technology. In this sense, this research proposes a numerical study to describe drying of sugarcane bagasse, using the cyclone as dryer. To this end, it was adopted the Eulerian-Lagrangian model in steady state. The Reynolds stress model was adopted to describe turbulence of the gas phase, while the lumped model in transient state was adopted to describe heat and mass transfer of the particulate phase (sugarcane bagasse). Particles were considered with irregular shape, composed of a binary mixture (solid part and water). The solution of the proposed model was obtained using the commercial software Ansys CFX 12. Results obtained for moisture content, temperature, dimensional variation, and paths of particles, as well as velocity distribution, pressure, and temperature of the gas phase inside the cyclone are presented and analyzed. It has been found that the obtained components for axial and tangential velocity inside the cyclone are in good agreement with experimental data available in the literature, and that the drying kinetics, heating, dimensional variations, and residence time of particles are affected by the velocity profile of the gas phase, by the velocity of particles, and the direction of flow of gas and particles at the entrance of the feed duct (clockwise and counter-clockwise).