Performance Improvement of a Gas Turbine Power Plant in Nigeria by Exergy Analysis: A Case of Geregu 1

This paper presents the performance improvement study of gas turbine power plant in Nigeria by exergy analysis method using Geregu 1 gas turbine power plant as a case study. The study analyzed the system’s components separately in order to identify the sites where the largest exergy losses occur and to quantify the amount. Results of the component efficiencies based on their thermodynamic models of energy and exergy analyses at design and operating years of the power plant revealed that the maximumexergy destruction efficiency occurred in the combustion chamber. Improvement approaches made on the performance of the combustion chamber included: 1) Increasing turbine inlet temperature at constant pressure ratio; 2) Increasing combustion chamber pressure ratio at constant turbine inlet temperature; and 3) Increasing both turbine inlet temperature and pressure ratio. Results of improvement conditions show that the first condition produced progressive decrease in exergy efficiency for the design and operating years when temperature was increased from 1060？C - 1080？C at 11 bar pressure. Second condition resulted to increase in exergy efficiency when pressure increased from 11 bar to 15 bar. Similarly, increasing turbine inlet temperature and pressure by 20？C and 4 bar respectively increased the exergy efficiency by 0.22% on design condition. In addition the exergy efficiency of the operating years increased with increase in both temperature and pressure at the amount. Hence, pressure variation affects exergy efficiency of combustion chamber.