Title: Exergy analysis and optimisation study of eliminating negative effects of electrical load variations in steam power plants

Authors: Behnam Roshanzadeh; H. Ahmadi-Danesh-Ashtiani

Addresses: Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, 1777613651, Iran ' Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, 1777613651, Iran

Abstract: Energy consumption is increasing rapidly in the world, and sustainable development has been considered as one of the main goals for the countries. Existence of strong connection between permanent energy supply and sustainable development is undeniable, and power plants are known as the main source of energy supply in the world. In this paper, energetic and exergetic analyses of a steam power plant are performed, and the effect of electrical load variations on energy and exergy efficiencies is studied. Load may decrease due to environmental considerations or operation of the power plant during the night, but the results show that lowering the load has negative effects on energy and exergy efficiencies, specific fuel consumption and CO₂ production per unit of power. Moreover, exergy analysis reveals that turbine's control valves play a considerable role in exergy destruction of the power plant. Based on these results, an optimisation is proposed which makes the efficiencies, specific fuel consumption and carbon dioxide production per unit of power almost independent from the load variations.

Keywords: energy; exergy; specific fuel consumption; CO₂ production; fossil fuels; sustainable development; optimisation; power plant; control valves.

DOI: 10.1504/IJEX.2018.093898

International Journal of Exergy, 2018 Vol.27 No.1, pp.21 - 42

Received: 19 Jul 2017
Accepted: 23 Feb 2018
Published online: 08 Aug 2018 *

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