ABSTRACT

Gas turbine power plants have gained a wide spread acceptance in the power generation and mechanical drive. Their compactness, high power to weight ratio, ease of installation, early commissioning, fast starting and quick shut down time have made them popular prime mover.Drop in gas turbine efficiency and reliability are tied to many factors which includes;operation mode, poor maintenanace procedures, age of plant, discrepancies in operating data, compressor inlet temperature, etc.This thesis describes the use of energy, exergy and reliability analysis in evaluating the performance of two gas turbine units (GT16

& GT19) in Delta IV of transcorp’s power station and their results were compare based on their thermodynamic efficiency and reliability.These analyses were conducted using the operating and reliability data collected from the units daily log sheets for the period of four years (2015,2016,2017, and 2018). In energy analysis , first law of thermodynamics were applied to each components of the two gas turbine units. Exergy analysis,mass and energy conservation laws were applied to each component of the two units. Number of failures, Downtime, MTBF, MTTR and Uptime were used to evaluate the reliability of each units.The results of energy analysis of GT16 & GT19 revealed that the overall efficiency,thermal efficiency,heat rate, thermal power, Specific fuel consumption, and work ratio,energy loss in combustion chamber and total energy loss in the plants are 25.36%, 25.62%,13648.58KJ/KWh,98.005MW,0.28865Kg/KWh,0.40344,1667322.42MW,1671309.1M W and 25.62%, 26.64%,13512.701KJ/KW-h, 98.792MW,0.28580Kg/KW-

h,0.40078,1471386.06MW,1476691.16MWrespectively. Furthermore, the results revealed that the Overall efficiency, thermal Efficiency, Thermal Power decreases as a result of increases in Compressor Inlet Temperature. However, Specific Fuel Consumption, Heat Rate increases with increase in Compressor Inlet Temperature.The Work Ratio decreases with increase in Compressor inlet Temperature, and this Confirmed that gas turbine are susceptible to high irreversibility at high Compressor inlet Temperature.Therefore, for optimum efficiency of the Gas turbine Unit, Cooling of the Compressor inlet Temperature is required. Also,exergy analysis showed that the turbine had the largest exergy efficiency of 94.31% and 94.68% respectively, while that of the total plant was 52.66% and 52.93% respectively. The combustion chamber had the highest exergy destruction of 39.63% and 39.23% respectively, while that of the total plant are 47.34% and 47.07% respectively. The results revealed that the Combustion chamber is the most exergy destructive component compared to other cycle component in each Units.Also, Its exergy efficiency is lower than that of other components studied due to the high temperature difference between working fluid and burner temperature.Increasing gas turbine inlet temperature(GTIT),the exergy destruction of this component can be reduced. Reliability results of the units revealed that the average reliability of gas turbine unit (GT19) is 68.05% and average reliability of gas turbine Unit (GT16) is 66.53% respectively. However,effective maintenance management practice have to be done on both units for maximum efficiency and reliability. Conclusively, having carrying this research, it was discovered that Gas turbine unit 19(GT19) is better in terms of thermodynamic efficiency and reliability than that of Gas turbine unit 16(GT16).However,effective maintenance management practice have to be done on both units to ensured maximum efficiency and relability.