A molten salt bypass flow steam temperature control strategy for steam generation system: system design, simulation modelling and validation

The steam generation system (SGS) is a critical thermal energy storage system, as it is responsible for converting stored thermal energy into useable steam, thereby enhancing the energy conversion efficiency and stability of the system. To address the challenge of steam temperature deviations during variable load conditions and to maximize the peaking potential of solar tower power plant, this study proposes an innovative steam temperature control strategy for SGS engaged in rapid peaking operations. A mathematical model of SGS and steam turbine assembly is established using the lump parameter method. Systematic step disturbance experiments are implemented on four variables, encompassing the salt side, water side, and the unit itself. The proposed control strategy is validated, demonstrating precise control of steam temperature and improving the subcooling degree of feed water at the preheater outlet by 1–2 °C. The strategy effectively maintained steam temperature within the target range of 540 ± 1 °C, showing superior stability compared to units without this control strategy, which exhibited main steam temperature deviations of 6.71 °C and reheat steam temperature deviations of 11.04 °C. This control strategy successfully decouples load and steam temperature, regulates the distribution of heat load in different heat exchangers, and ensures the safe and stable operation of the unit during rapid load changes.