Analise energética e exergética de uma usina do setor sucro-alcoleiro

Abstract

In the present work, analyzes were performed through the First and Second Law of Thermodynamics of three cogeneration configurations in a sugarcane industry plant. The initial configuration, represented by Case 1, shows the current configuration of the plant, consisting of low-pressure boilers, back-pressure turbines to drive mechanical equipment and power generation and a pressure reducing valve. All low pressure steam is used for sugar and alcohol production and all electricity is consumed, in this configuration there is excess bagasse. In Case 2, any excess bagasse is burned in the boiler and the pressure reducing valve is removed. In Case 3, all turbines responsible for driving the machines were replaced by electric motors and a condensing turbine was added. Through the First and Second Law of Thermodynamics it was possible to determine the efficiencies of each component and through the indices compare all configurations. Changes in the system showed that in Cases 2 and 3 there was a power surplus of 3.38MW and 10.35MW respectively and there was also an increase in cogeneration electrical efficiency. In addition, exergy destructions were calculated and it was possible to identify exactly where the greatest irreversibilities occur.