THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

Xiangyu Zhang

,

Zhaoyao Ma

,

Hainan Wen

,

Zhenshuai Yang

,

Hui Liu

online first only

Study on the characteristics of molten salt heat storage in the fast peak regulation of coal-fired power unit

ABSTRACT
The load variation rate of the coal-fired power unit in China is generally around 2%, and the new technology is needed to further improve the load variation rate and to increase the peak regulation benefits. In this paper, the molten salt is utilized to constructed the "Carnot battery" based on the coal-fired power unit, in order to increase the load variation rate of the coal-fire power units, and the regulatory characteristics of the molten salt system during load variation processes and the coupling characteristics with the boiler and turbine are investigated. The results indicate that, the load variation rate in the 20-100% load can be improved to 6%Pe/min for a 300MW coal-fired power unit when molten salt system with power of 301MW and thermal storage duration of 83.6MWh is coupled, in which the maximum molten salt temperature is 420°C, and the steam produced by molten salt is added into the low-pressure cylinder of turbine. The average power generation efficiency of the "Carnot battery" constructed by the boiler and molten salt during the variable load regulation process is 38.72%, and the average power generation efficiency of the molten salt system is 24.57%. This study indicates that the small-scale molten salt systems can be used to improve the load variation rate of the coal-fired power units.
KEYWORDS
coal-fired power unit, molten salt, load variation rate, low-pressure cylinder, Carnot battery
PAPER SUBMITTED: 2023-12-17
PAPER REVISED: 2024-01-08
PAPER ACCEPTED: 2024-01-11
PUBLISHED ONLINE: 2024-03-10
DOI REFERENCE: https://doi.org/10.2298/TSCI231217066Z
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Study on the characteristics of molten salt heat storage in the fast peak regulation of coal-fired power unit