Performance and Exergoeconomic Analysis of a Gas Turbine Power Plant in Port Harcourt, Nigeria

The performance and exergoeconomic analysis of a simple cycle General Electric (GE) gas turbine power plant located at Trans-Amadi, Port Harcourt, was conducted in this study. The data for the analysis were obtained from the power plant log sheets. The study was to assess the exergy destruction rates and the associated cost of exergy destruction across the plant components. The computation and simulation were done with the MATLAB software using EXCEM, SPECO and ECDD analysis methods. Results of performance analysis revealed that the net electric power output ranges from 9.95MW to 10.64MW as against the 25MW installed capacity per unit and thermal efficiency ranging from 17.82% to 18.68%. Calculation showed that the firing temperature of the combustor is 41% of 2525K adiabatic flame temperature which depends on the fuel heating value and the temperature of the burning gases. This low firing temperature shows that a significant amount of heat loss occurs in the combustor. Exergy analysis also revealed that the combustion chamber suffers a high rate of exergy destruction, and that the plant has an overall exergy efficiency of 10.95%. Exergoeconomic analysis revealed that a total cost of $1199.77 is required to generate electricity per hour of which 25% results from exergy destruction.  An average exergoeconomic factor of 42% across the plant components shows that more resources are being used up to compensate for the high rate of exergy destruction. This work therefore revealed that compression work and exergy destruction rate increase with increasing ambient temperature leading to a decrease in electric power output. The high rate of exergy destruction is caused by inefficiency of the plant component material type and the high frictional effect encountered by the turbine shaft during rotation and work transfer.