Performance improvement of coal-fired power generation system integrating solar to preheat feedwater and reheated steam

Abstract

Solar aided power generation (SAPG) technology has been proven as an efficient way to use solar energy for power generation purpose. In a SAPG plant, a solar field consisting of parabolic solar collectors is normally used to supply the solar heat to preheat feedwater and replace the high-pressure extraction steam. However, the outlet temperature of reheated steam decreased with the integration of solar thermal which sacrificed the system performance. As an improvement, the second solar field was proposed to preheat the reheated steam to maintain its outlet temperature and the average temperature of regenerative Rankine cycle before or after solar integration. Through a case study using A 600MW supercritical SAPG plant operating in fuel-saving Using solar to preheat feedwater and reheated steam could improve overall cycle efficiency and solar-to-electricity efficiency by 1.91% and 6.01%, respectively. The solar share was expanded from 9.53% to 17.26%. The electricity generated per solar aperture area under the design condition was 187.96 W/m², which was 26.91% higher than that of the system without the second solar field.