Study on the general system integration optimization method of the solar aided coal-fired power generation system

Highlights: • A general system integration optimization method (GIOM) is developed. • GIOM is used to optimize the solar aided coal-fired power generation (SAPG) system. • GIOM can simulate different integration locations and heat distributions schemes. • A Solar Two-based SAPG system is optimized by the GIOM. • The solar-electric efficiency of SAPG system is greater than that of Solar Two. -- Abstract: Solar aided coal-fired power generation (SAPG) has been attracted more and more attentions in recent years. However, its integration and optimization is a rather challenging work. Most of the studies are based on the researches of one or several certain schemes, and no general system integration optimization method (GIOM) considering all possibilities has been proposed. In this paper, a general system integration optimization model is developed, which is configured with 8 virtual molten salt heat exchangers (FH_ms) and used to simulate any scheme of different integration locations and heat distributions. A SAPG system based on Solar Two plant and a 600 MWe supercritical coal-fired plant is studied. The results show that at the relatively higher heliostat field power (HFP) work conditions, the heat energy should be injected into the highest pressure feedwater heater (FH_s) as a priority. While at the relatively lower HFP and higher turbine power work conditions, the heat should be distributed to the two highest pressure FH_s in a certain proportion instead of fully distributed to the highest pressure FH_s. The performances of both the receiver and the power block are improved. The solar-electric conversion efficiency of SAPG system is obviously higher than that of Solar Two.