THERMAL SCIENCE

International Scientific Journal

USING MOLTEN-SALT ENERGY STORAGE TO DECREASE THE MINIMUM OPERATION LOAD OF THE COAL-FIRED POWER PLANT

ABSTRACT
As the renewable energy fluctuating in the power grid, the traditional coal-fired power plant needs to operate on the extremely low load, so as to increase the share of renewable energy. This paper deals with thermodynamic simulation and exergy analysis of the coal-fired power plant integrated with the molten-salt energy storage system to explore the potential of reducing the minimum operation load. A steady-state simulation was performed to obtain the thermodynamic properties of process streams in a subcritical 600 MW unit. The results indicated that with simple main steam and re-heat steam energy storage plan, the storage efficiencies are 39.4-42.9% and 51.3-51.4%, the minimum operation load would decrease by 27.2 MW, 10.6 MW, respectively. Exergy analysis shows that the exergy loss mainly comes from the throttling process and temperature difference in the phase-changer heat transfer process. With optimized Molten-salt energy storage plans, the storage efficiencies increase to 72.6% and 78% via lead the exhaust drains or steam into higher pressure points; the minimum operation load decreases by 35.1 MW and 3 MW, respectively. Moreover, with the coupled plan including both optimized main steam and re-heat steam energy storage system, the minimum operation load would decrease by 80.7 MW, and storage efficiency is 75.1%.
KEYWORDS
PAPER SUBMITTED: 2019-10-15
PAPER REVISED: 2019-11-25
PAPER ACCEPTED: 2019-12-10
PUBLISHED ONLINE: 2020-01-19
DOI REFERENCE: https://doi.org/10.2298/TSCI191015009F
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2020, VOLUME 24, ISSUE 5, PAGES [2757 - 2771]
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© 2020 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence