Optimization of flexibile peak shaving system of coal-fired unit aided by molten salt heat storage based on economic analysis

doi:10.19799/j.cnki.2095-4239.2025.0304

Abstract

Abstract:

The coupling of molten salt heat storage and coal-fired power unit can effectively regulate unit output and improve unit flexibility. In this article, based on a 600 MW coal-fired unit as the research object, 3 operation schemes for peak shaving aided by molten salt heat storage are constructed, including heat storage from extracted main steam and heat release to bypass feedwater, deaerated water and condensate water. The economic performance of 3 schemes is compared and analyzed by studying the effects of factors such as return water parameters of extracted main steam, heat storage/release power, and heat storage/release duration on economic indicators such as payback period and levelized cost of energy (LCOE). The results indicate that as the return water temperature increases, the payback period of the 3 schemes gradually shortens, while the LCOE slightly rises. The scheme of bypass feedwater has the best economic performance. When the return water temperature is 309.4 ℃, the heat storage/release power is 25 MW, and the heat storage/release duration is 1 hour, the payback period is 5.521 years, and the LCOE is 0.4485 yuan/kWh. With the increase of storage/release power and duration, the payback period and LCOE of this scheme have both increased.

Key words: coal-fired power unit, molten salt heat storage, peak shaving, flexibility, economy analysis

CLC Number:

TK 284.1

Bin WANG, Jinkai LIU, Xiaoxia JIANG, Ning BAI, Yuanwei LU. Optimization of flexibile peak shaving system of coal-fired unit aided by molten salt heat storage based on economic analysis[J]. Energy Storage Science and Technology, 2025, 14(7): 2729-2737.

Figures/Tables 9

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热力指标	数值
热力指标	100%额定负荷	50%额定负荷
主蒸汽流量/(t/h)	1848.79	900.11
主蒸汽压力/MPa	16.67	9.77
主蒸汽温度/℃	538.00	538.00
再热蒸汽流量/(t/h)	1576.13	798.27
再热蒸汽压力/MPa	3.41	1.75
再热蒸汽温度/℃	538.00	538.00
1号抽汽压力/MPa	6.08	3.09
2号抽汽压力/MPa	3.79	1.94
3号抽汽压力/MPa	2.05	1.06
4号抽汽压力/MPa	1.02	0.53
5号抽汽压力/MPa	0.62	0.32
6号抽汽压力/MPa	0.24	0.128
7号抽汽压力/MPa	0.08	0.04
发电功率/MW	600.18	300.11
热耗率/(kJ/kWh)	8064.00	8653.00

参数	设定值
高温熔盐温度/℃	365.9
低温熔盐温度/℃	160.0
抽汽回水温度/℃	309.4
储热功率/MW	25
释热功率/MW	25
日储热时长/h	1
日释热时长/h	1
储热基准工况	50%额定负荷
释热基准工况	50%额定负荷
机组日发电小时数/h	24
机组年发电天数/d	300