Exergoeconomic Analysis for Unit Gt14 of South Tripoli Gas Turbine Power Plant

Exergoeconomic (thermoeconomic) analysis is performed for the unit GT14 of South Tripoli (Libya) gas turbine power plant. The designed electrical power of the unit is 100MW (based on ISO conditions). The full operating load (electrical) is 85MW. The analysis is based on real time data and performed for three different loads; those are 85% (full operating load) 60%, and 40% of design load.A systematic and general methodology for defining and calculating exergetic efficiencies, exergy destruction and exergy related costs in thermal systems is presented. The methodology is based on the Specific Exergy Costing approach. Results of exergy analysis show the exergetic efficiency increases from 20.54% at 40% design load to 29.12% at full operating load, and hence, the ratio of the total exergy destruction to fuel input exergy decreases from 61.03% at 40% design load to 48.63% at full operating load load, and the ratio of exergy loss with the exhaust gases to the input fuel exergy slightly increases from 18.43% to 22.25%. Results of exergoeconomic analysis show the average cost per unit exergy net power equal to 7.1$/GJ at 40% design load, and equal to 5.5$/GJ at 60% design load, and equal to 4$/GJ at full operating load . It is found that the cost of exergy destruction in the combustion chamber presents the main contribution to the total cost of exergy loss; its value varies in the combustion chamber from 1474$/h at 40% design load to 1123$/h at the full operating load. The contribution and the variation of cost of exergy destruction with load are lower for the other two main components