A Study of Single Shaft Gas Turbine based Cogeneration Plant Mode of Operation for Performance Evaluation

A gas turbine generally runs at off-design conditions due to change of load or ambient conditions. Therefore, when evaluating the overall performance of the gas turbine, it is important to account for all operating conditions that can be encountered. The cogeneration plant considered for this stud...

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Bibliographic Details
Main Authors: Baheta , Aklilu Tesfamichael, Gilani, Syed IhtshamUl-Haq
Format: Conference or Workshop Item
Published: 2009
Subjects:
Online Access:http://eprints.utp.edu.my/5542/1/FTEC_2009.pdf
http://eprints.utp.edu.my/5542/
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Summary:A gas turbine generally runs at off-design conditions due to change of load or ambient conditions. Therefore, when evaluating the overall performance of the gas turbine, it is important to account for all operating conditions that can be encountered. The cogeneration plant considered for this study consists of a single shaft gas turbine and a heat recovery steam generator (HRSG). The gas turbine in turn consists of an axial compressor that has an inlet guide vane and variable stator vanes (VSVs). At off-design the VSVs are re-staggered so that it would improve the cogeneration performance. Furthermore, two modes of operation were identified. The first mode is for part load less than 50% running to meet the power demand by regulating the fuel mass flow while the VSVs are fully opened. The second mode is for part load greater than 50% running to meet both the power demand and to maintain the exhaust gas temperature set value so that it would be used to produce steam. This is done by regulating both the fuel mass flow and compressor VSVs position. Therefore, this work aims at the study of the mode of operation of a single shaft gas turbine based cogeneration plant for performance evaluation. To accommodate the change of the compressor performance map with each VSVs opening, correction coefficients are introduced. The effect of variation of power (relative load) and ambient temperature on cogeneration parameters such as fuel consumption, temperatures, pressures, VSVs openings and efficiencies were studied. This model serves as the basis of an advanced strategy to evaluate a stationary gas turbine’s overall operation. Comparisons between the field data and simulation results demonstrate a good degree of agreement. To support the huge amount of calculations required for off-design analysis, a computer program was developed in MatLAB environment.