Optimization of Repowered Steam Power Plant via Thermoeconomic Analysis

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Abstract

Feed-water heating repowering is defined as using gas turbine(s) flue gasses energy for recovery by steam plant feed water heaters. Minimizing related total cost in new thermal system is the critical subject, beside of this purpose an optimal balance between capital cost investment and exergy destruction should be considered. In this research feed water heating repowering modeling of Shahid Rajae steam plant has been performed in the next stage, optimization of mentioned system variables has been done based on thermoeconomic objective functions. Then objective functions sensitive analysis in contrast of steam turbines extraction flow rates have been performed and optimum amount of flow rate are determined by using Genetic algorithm. As a result of this optimization, some of technical and economical system properties have been upgraded. Thermal efficiency and exergy efficiency are anticipated to be 42.2 and 40.17 respectively and exergy destruction cost is increased about 1 to 16 percent also it should be mentioned that 26 months has been derived for optimum period of preliminary capital return.

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