关键词: 熔盐储能, 热电联产, 电力调峰, 仿真模型, 经济性分析, 灵活性改造

Abstract: Combined Heat and Power (CHP) units utilize part of the steam that has performed work as a secondary product for heating or industrial steam supply, which is an important approach for in-depth energy conservation and emission reduction. However, the operation mode of CHP units—where power generation is determined by heat demand—limits their deep peak-shaving capability. Molten salt energy storage technology can enhance the operational flexibility of units and achieve heat-power decoupling to a certain extent. Therefore, taking a 660MW generator set with a steam supply capacity of 150t/h (at 1.8MPa and 300℃) as a case study, the EBSILON software was used for modeling to optimize the conventional steam supply scheme of desuperheating and depressurizing the thermal reheat steam. By combining the ejector on the steam turbine side and the molten salt device on the heat network side, a new steam supply scheme was proposed—namely, the main steam ejecting thermal reheat steam coupled with molten salt. This scheme stores heat during the off-peak electricity price period and releases the stored heat during the peak electricity price period. The results show that: To provide industrial steam supply of 150t/h (at 1.8MPa and 300℃), the operating range of the unit's power generation capacity under the original steam supply scheme is 39.34%-94.08% THA (Turbine Heat Acceptance), while that under the molten salt-coupled steam supply scheme expands to 21.74%-99.17% THA. The molten salt steam supply scheme not only broadens the safe operation boundary for heat supply and extends the operating range of thermal power units but also provides a reference for the heat storage system to participate in the unit's operation and dispatching.In a typical day, the increased benefits after configuring the molten salt system mainly come from compensation benefits and coal-saving benefits: the coal consumption cost is reduced by 178,700 yuan/day, the new compensation benefit is 351,000 yuan/day, the daily profit is increased by 392,300 yuan/day, and the system payback period is 5.54years.

Key words: molten salt energy storage, combined heat and power generation, power peak shaving, simulation model, economic analysis, flexibility retrofit