Modelagem termodinâmica e simulação computacional de secador para bagaço de cana-de-açúcar

Abstract

This study aims to repurpose sugarcane bagasse (Saccharum officinarum L.) as a fuel for steam generation, used in the production of cachaça, by utilizing the exhaust gases from the boiler in the drying process. The high moisture content and low energy density of the biomass hinder the stability of combustion, leading producers to use eucalyptus firewood as fuel in boilers. To address this issue, thermodynamic modeling of combustion was performed with the help of the EES (Engineering Equation Solver) software, and a dryer was designed to reduce the moisture content of the sugarcane bagasse from distilleries, which leaves the milling process at 51.76% on a wet basis. The computational simulation of the dryer silo was carried out in the OpenFOAM software using the multiphaseEulerFoam solver and compared with the analytical solution performed in the EES software. The original project proposed the development of a compact fixed-bottom dryer with a 4-hour autonomy for the production of 1000 kg/h of steam, to carry out the drying process and boiler feeding automatically through a conveyor screw located at the base of the dryer. However, due to the high power required in the dryer silo fan to prevent water vapor condensation, a rotary dryer was chosen as a solution, resulting in a reduction of the fan power from 39.5 hp to 3 hp. The rotary dryer allowed for the evaporation of 111.13 kg/h of water vapor and reduced the biomass moisture content from 51.76% to 38.22% on a wet basis.