集成OSC与BEST的1000 MW超超临界二次再热机组热力性能研究  

Thermal Performance Study on 1000 MW Ultra-supercritical Double Reheat Unit with OSC and BEST

作　　者：王惠杰 高浩然 许小刚 赵建红 WANG Hui-jie;GAO Hao-ran;XU Xiao-gang;ZHAO Jian-hong(Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology(North China Electric Power University),Baoding 071000,China)

机构地区：[1]河北省低碳高效发电技术重点实验室(华北电力大学),保定071000

出　　处：《汽轮机技术》2025年第2期131-136,共6页Turbine Technology

基　　金：河北省自然科学基金(E2018502059)。

摘　　要：随着蒸汽参数的升高,二次再热机组普遍存在着抽汽过热度较高,加热器换热温差和;[火用]损失较大的问题,这阻碍了机组效率的进一步提高。以1 000MW超超临界二次再热机组为例,提出了2种优化方案。方案1采用外置蒸汽冷却器(outer steam coolers, OSC),方案2集成OSC和背压抽汽汽轮机(back pressure extraction steam turbine, BEST)。对3种方案的热经济性进行对比,并采用;[火用]分析法计算了系统部分单元的;[火用]损。结果表明:方案2能有效利用RH1~RH7的多级抽汽过热度,在较高负荷下的热经济性比方案1和参考系统高,100%THA下相比于方案1给水温度和循环热效率分别提高了6.24℃和0.48%,锅炉、汽轮机和回热系统;[火用]损失减小;随着负荷降低,方案2对给水温度、循环热效率和;[火用]损失的影响效果减弱,负荷低于50%THA后汽轮机的;[火用]损失略高于方案1和参考系统。因此相比于方案1和参考系统,方案2具有较高的热经济性。With the increase of steam parameters,exergy of secondary reheating units generally has problems such as higher superheat of extraction steam,temperature difference of heater heat exchange and greater loss of exergy,which hinder the further improvement of unit efficiency.The 1000 MW ultra-supercritical secondary reheat unit is taken as an example,and two optimization schemes are proposed.Scheme 1 with external steam cooler(outer-steamcoolers,OSC),the integration scheme 2 OSC and back pressure extraction turbine(back pressure extraction steam turbine,BEST).The exergic economy of the three schemes was compared,and exergic loss of some units of the system was calculated by exergic analysis method.The results show that scheme 2 can effectively utilize the multi-stage superheat of RH1-RH7,and the thermal economy under higher load is higher than scheme 1 and reference system.At 100%THA,the feed water temperature and cycle thermal efficiency of scheme 1 have increased by 6.24℃and 0.48%,respectively,and the exergic loss of boiler,turbine and regenerator system has decreased.With the decrease of load,the exergic loss of solution 2 on feed water temperature,cycle thermal efficiency and exergic loss decreased.The exergic loss of turbine with load below 50%THA was slightly higher than that of solution 1 and reference system.Therefore,compared with scheme 1 and reference system,scheme 2 has higher thermal economy.

关 键 词：超超临界机组 二次再热 过热度 [火用]分析 热经济性 

分 类 号：TK9[动力工程及工程热物理]