Performance Analysis and Components Irreversiblities of a (25 MW) Gas Turbine Power Plant Modeled with a Spray Cooler

Abstract

In this study the effect of inlet air cooling system and components irreversibilities on the performance of an active 25MW gas turbine power plant was investigated. The objective of this study was to establish the potential benefits of improving the performance of the current gas turbine plant into a more advanced cycle with high efficiency and power output through inlet air cooling. Problem statement: The hypothesis was that the low performance of the gas turbine plant was caused by high ambient temperature, the use of spray cooler was adopted to bring the air condition temperature close to ISO condition. Approach: In this study, performance characteristics were determined for a set of actual operational conditions including ambient temperature, relative humidity, turbine inlet temperature and pressure ratio. Results: The results obtained show that the use of a spray cooler on the existing gas turbine cycle gives a better thermal efficiency and less irreversibility rate in the components system and the entire plant. The power output of the gas turbine plant with spray cooler was found to have increased by over 7%, accompanied by 2.7% increase in machine efficiency with a reduction in specific fuel consumption of 2.05 and 10.03% increase in the energy of exhaust. Furthemore, a 0.32% reduction in the total irreversibility rate of the plant for the cooled cycle was obtained and a 0.39, 0.29 and 0.17% reduction in the irreversibility rate of compressor, turbine and combustion chamber respectively, were also obtained. Conclusion: The results show that retrofitting the existing gas turbine plant with inlet air cooling system gives a better system performance and may prove to be an attractive investment opportunity.