摘要
以某660 MW超超临界二次再热机组为案例,针对超超临界二次再热机组回热抽汽过热度偏高的问题,提出了集成回热式汽轮机且单独配置发电机的4种集成方案,采用热量平衡法和火用分析法将它们与常规机组(基准系统)、加装两级外置式蒸汽冷却器的二次再热机组(参比系统)进行热力性能的对比研究,获得最优集成方案,并对最优方案与参比系统进行变工况下抽汽过热度和能耗的对比研究。结果表明:方案4中回热加热器的总火用损最小,方案3中机组的发电煤耗和总火用损均最小,发电效率达48. 05%;在变工况下方案3中回热加热器的火用损始终低于参比系统的;与基准系统相比,在不同负荷下方案3的节煤量均大于参比系统。研究成果将为超超临界二次再热机组抽汽回热系统的节能和改造提供有益的理论指导。
To solve the overheat problem of regenerative steam extractions,this paper took the case of a 660-MW ultrasupercritical reheating coal-fired power plant,and proposed four system schemes integrated with regenerative steam turbine and independent generator configuration.To know their thermal performance and to gain optimal system scheme,this paper compared their performances with those of the conventional unit(base system)and reheating unit equipped with two outer steam coolers(reference system)through energy balance method and exergy analysis method.The offdesign conditions of both the optimal system scheme and the reference system were further studied in terms of regenerative extraction superheat degree and system energy consumption.The research results showed that the in scheme 4,the total exergy loss of regenerative heaters is the lowest,and that in scheme 3,both the total system exergy losses and coal consumption rate for power generation are the lowest and the power generation efficiency is the highest,up to 48.05%.The exergy losses of the regenerative heater in the scheme 3 are always less than those of the reference system under off-design conditions.Compared with the reference system,the amounts of coal saving in scheme 3 under variable load conditions are all greater than those of the reference system.The achievements in this paper will provide theoretical guidance for the energy saving and improvement of the regenerative system of ultra-supercritical reheating coal-fired power plant system.
作者
段立强
孙婧
DUAN Liqiang;SUN Jing(School of Energy Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China)
出处
《华北电力大学学报（自然科学版）》
CAS
北大核心
2019年第3期80-89,共10页
Journal of North China Electric Power University：Natural Science Edition
基金
国家重点研发计划项目(2017YFB0602101)
关键词
二次再热
变工况
设计优化
回热式汽轮机
节能
reheating
off-design conditions
design optimization
regenerative steam turbine
energy saving
