Thermal and hydraulic performance of molten salt steam generation system under varying operating conditions in concentrating solar power plants

To conduct the thermal transport characteristics and operational stability of the steam generation system (SGS) under partial load conditions in concentrating solar power (CSP), a real-scale shell-and-tube steam generator hydrodynamics predictive model is developed. This model integrates lumped parameter methods with the finite volume method to account for heat transfer and phase change. Additionally, in accordance with the prevailing water circulation mode in the CSP plant, a typical model of the natural circulation system is established, while optimal stable operating points of the maximum circulation mass flow rate under varying operating conditions are determined. The results indicate that the inherent stability of the generator strongly lies in the dynamic compromise between its thermodynamic and hydrodynamic characteristics. Under high load conditions, the natural circulation mode demonstrates excellent flow stability. Operating at lower operating pressures results in greater circulation flow and a heightened sensitivity to phase changes. Under system pressures of 13.76, 11.08, 8.39, and 6.71 MPa, the recommended circulation ratios are determined to be 5.38, 7.86, 11.95, and 16.07, respectively. Furthermore, the stability of the circulation curve is optimized by adjusting the structural dimensions of the steam generator. The sensitivity to evaporation capacity and heat exchanger effectiveness is assessed.