Análise termodinâmica, exergética e termoeconômica de um ciclo combinado com resfriamento do ar de entrada

Abstract

In the last decades, thermoelectric power plants have been at highlights in the Brazilian energy sector due to the increase in energy demand and the search for greater reliability of the generation system, due to the increase of periods of Affluent Natural Energy (ANE) below Average of Long Term (MLT) in the southeast, region with the largest reservoirs in the country. Because it is a non-renewable energy, studies that provide a better performance in the use of thermal energy are required. In this way, this work proposes the analysis, through simulation in the EES (Engineering Equation Solver) software, of a thermoelectric combined cycle power plant with the use of two systems for the gas turbine inlet air cooling, being the evaporative cooling and the cooling by the mechanical steam compression method, to analyze the possible generation gains in two cities, Porto Alegre - RS and Mossoró - RN. The results show an improvement in the behavior of the plant in all aspects with the addition of cooling. Evaporative cooling provided an increase of 0.9% and 1.5% in annual average energy generation in Porto Alegre and Mossoró, and 0.5% and 0.8% exergetic efficiency, respectively. The unit cost of energy decreased from US$ 120.13 / MWh to US $ 114.88 / MWh in Porto Alegre and from US$ 121.17 / MWh to US$ 118.6 / MWh in Mossoró. The use of mechanical steam compression cooling resulted in an average increase in the annual power generation of 5.6% in Porto Alegre and 8.5% in Mossoró and 0.5% and a 0.6% increase in exergetic efficiency, in the same order. The unitary value of energy reached US$ 113.71 / MWh in Porto Alegre and US$ 117.08 / MWh in Mossoró.