Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
ANALYSIS OF A HUMID AIR CYCLE IN A GAS TURBINE
Submission Author:
Felipe Raul Ponce Arrieta , MG
Co-Authors:
Alexandre Monteiro Cruz, Aurelio Alves, Hairton Júnior José da Silveira
Presenter: Felipe Raul Ponce Arrieta
doi://10.26678/ABCM.ENCIT2016.CIT2016-0439
Abstract
The project aims to analyze the costs and the generation of electrical energy from a humidified air gas turbine cycle. A research was made on the variations of humidified air cycles proposed for gas turbines applications. The analysis target the power levels, efficiency and optimum operating points in order to choose which enables to the higher power generation. A numerical simulation performed in the cycle in software Gate Cycle™ checked the environmental parameters that influence the cycle performance. The main points of variation were the outlet temperature of the combustion chamber, as well as the pressure ratio of the compressor and the turbine. Graphics were plotted for thermal efficiency and the specific power of the cycle related to the cycle pressure ratio using turbine inlet temperatures from 900 to 1400ºC, thus enabling us to evaluate the best point of operation. In addition, the use of the gas saturator and the recuperator was fundamental to increase the mass flow of air in the system, which influences the global efficiency of the cycle. The condenser of contact was essential for the reuse of the water in the operation of the cycle and in the additional production of drinking water. The performed analysis made it possible to study the performance of the system, with the ambient temperature ranging from 5 to 30°C. The design point was chosen for a turbine inlet temperature of 1100ºC and a cycle pressure ratio of 13, in which a higher efficiency (51.93%) is reached with a medium exergetic cost (2.001) without compromising the physical and metallurgical properties of the system. The saturator obtained a gain of 0.3022 kg/s on airflow, increasing the power of the cycle and thus reaching 1.078MW on the simulation. The fluid gas condensers obtained surplus of 0.6792 kg/s of potable water. The system showed generation cost of 39.83 R$/MWh, which is competitive in the Brazilian electricity market. Regarding the off-design analysis, the increment on the environment temperature results on higher generated power, unit exergetic cost and exhaust temperature, and also a depletion of the exergetic and the energetic efficiency caused by the rise of the exhaust energy.
Keywords
Gas Turbine, Thermal Efficiency, Exergy Analysis, Numerical simulation
