Cold-end integration of thermal system in a 1000 MW ultra-supercritical double reheat power plant. (5th July 2021)

• Record Type: Journal Article
• Authors: Lin, Xiaolong; Song, Huchao; Wang, Lukai; Guo, Yifan; Liu, Yinhe
• Is Part Of: Applied thermal engineering. Volume 193(2021)
• Publication Date: 2021-07-05
• Subjects: Flue gas heat recovery -- Superheat utilization -- Partial load conditions -- Efficiency improvement -- Techno-economic analysis; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2021.116982
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: A novel thermal system for the coal-fired power plant is proposed. Exergy loss in the air preheating process is greatly reduced. Superheat degree of extraction steam is effectively reduced. Power supply efficiency is significantly improved. Greater economic benefits are achieved. Abstract: More attention has been paid to the ultra-supercritical double reheat power plant due to its high thermal efficiency. Excessive exergy loss from the low-grade heat recovery process of flue gas, and the high superheat degree of extraction steam, especially under partial load conditions, hinder the further improvement of its thermal efficiency. In this paper, a novel double reheat power plant integrating the process heat between the flue gas at the boiler cold-end and regenerative system is proposed to reduce the exergy loss in the waste heat recovery process of flue gas and fully utilize the extraction steam superheat degree under various load conditions. The thermodynamic and techno-economic analyses are performed for the case and novel units. The results reveal the following: The power supply efficiency of the proposed system improves by 0.81% points compared with the conventional unit under turbine heat acceptance load, which is a clear improvement from findings of previous studies. Moreover, the proposed system also exhibits a better thermodynamic performance under partial load conditions. The break-even point of the proposed system is 5.28 years and the net present value is 10.98 M$. Overall, the novel design is feasible and profitable.