Energy and Exergy Analysis of a 200 MW Combined Cycle Thermal Power Plant

Abstract

Most of the engineering analyses and energy balance of control volume systems are based upon the first law of thermodynamics which asserts that the work, energy and heat are interconvertible and there is no distinction among them. On the other hand, second law of thermodynamics states that these forms of energy do not have same quality. They are quantitatively same but qualitatively different, i.e., at different temperatures the heat transfer from a system to another having same temperature gradient is different. The measure of energy quality is known as exergy.  Exergy is the maximum extractible work from a thermodynamic system in equilibrium with its surroundings and it is the index of perfectness of a thermal system. This paper presents the exergy and energy analyses of different components of Nishat Power Limited, Pakistan. The plant is consists of a 200 MW combined cycle thermal power plant, 11 compression ignition engines (17 MW each) and one steam turbine of 15 MW. Discrete analysis of individual components of the system to calculate energetic and exergetic losses based on data from the power plant running at full capacity has been performed.   The loss of energy to the environment in steam generator and turbine have been noted as 561.18 kW and 114.12 kW, respectively. A comparison between energetic losses and exergetic losses has also been presented.