Exergoeconomic and exergoenvironmental evaluation of the coupling of a gas fired steam power plant with a total site utility system

Abstract

The purpose of a steam power plant usually is electrical power generation; however, it can work as dual purpose plant producing steam and power simultaneously. In this paper we seek the optimum integration of a steam power plant as a source and a site utility system as a sink of steam and power. Estimating the cogeneration potential prior to the design of a central utility system for site utility systems is important for setting targets for site fuel demand as well as heat and power production. In this regard, an accurate cogeneration targeting procedure is used for the coupling of a steam power plant and a site utility consisting of a process plant. Exergoeconomic and exergoenvironmental evaluations are performed. In the exergoenvironmental analysis, the environmental impacts obtained by life cycle assessment (LCA) are apportioned to the exergy streams, identifying the main system components with the highest environmental impacts and possible improvements associated with these components. Moreover, exergoenvironmental variables are calculated, and an exergoenvironmental evaluation is carried out. In addition, the cogeneration targeting method has been applied. A gas fired steam power plant and a process site utility are considered as a case study, with the integration of steam levels of the steam power plant and the site utility system carried out using the new procedure presented in this paper.