Thermo-economic analysis of typical thermal systems and corresponding novel system for a 1000 MW single reheat ultra-supercritical thermal power plant

摘要

In this study, thermodynamic analysis of the bypass flue (BPF) thermal system and the "bypass flue integrated with steam-air heater (BPF-SAH)" thermal system is carried out by taking a 1000 MW single reheat ultra-supercritical coal-fired power plant as a case unit. Although these two typical thermal systems can improve the power supply efficiency of power plant to 43.68% and 43.74%, respectively, there is still excessive exergy loss in the air preheating process on the boiler side. To achieve better heat utilization of flue gas, a novel thermal system with integrated steam-air heaters (SAHs)is proposed. The thermodynamic analysis results show that the power supply efficiency of the integrated SAHs thermal system reaches 43.89%, which is 0.82% points higher than that of the case unit, and the integrated SAHs thermal system overcomes the shortcomings of these two typical thermal systems. Techno-economic analysis comparison of these three types of thermal systems reveals that the integrated SAHs thermal system shows the best techno-economic performance and is feasible in engineering, and the dynamic investment payback period and the net present value of the 30 years lifespan are 2.36 years and 20.412 million USD, respectively.