THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

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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 (CFPP) integrated with the molten-salt energy storage (MSES) system to explore the potential of reducing the minimum operation load (MOL). A steady-state simulation was performed to obtain the thermodynamic properties of process streams in a subcritical 600MW unit. The results indicated that with simple main steam and reheat steam energy storage plan, the storage efficiencies are 39.4%-42.9%, 51.3%-51.4%, And the MOL would decrease by 27.2MW, 10.6MW, 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 MSES plans, the storage efficiencies increase to 72.6% and 78% via lead the exhaust drains or steam into higher pressure points; the MOL decreases by 35.1MW and 3MW, respectively. Moreover, with the coupled plan including both optimized main steam and reheat steam energy storage system, the MOL would decrease by 80.7MW, 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
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