1000MW超超临界机组回热抽汽过热度多种利用形式的热力学分析  

Thermodynamic Analysis on the Superheating Degree Utilization Modes of 1 000 MW Ultra-supercritical Units

作　　者：周璐瑶[1] 徐钢[1] 白璞[1] 许诚[1] 杨勇平[1] 

机构地区：[1]华北电力大学国家火力发电工程技术研究中心,北京102206

出　　处：《动力工程学报》2017年第6期495-500,512,共7页Journal of Chinese Society of Power Engineering

基　　金：国家重点基础研究发展计划(973计划)资助项目(2015CB251504);国家自然科学基金资助项目(51476053;U1261210)

摘　　要：针对1 000 MW超超临界机组抽汽过热度过高的问题,分析了一级外置式蒸汽冷却器(简称外冷器)系统和二级外冷器系统的节能效果,并与小汽轮机相对内效率分别为85%和90%的回热式小汽轮机系统的节能效果进行了比较,同时分析了不同负荷条件下蒸汽过热度多种利用形式的节能效果.结果表明:在额定负荷工况(THA工况)下,回热式小汽轮机系统的节能效果始终优于外冷器系统;回热式小汽轮机系统的节能效果随着其相对内效率的提高而提升,外冷器系统的节能效果随着级数的增加而提升;负荷降低时,外冷器系统的节能效果有所改善,回热式小汽轮机系统的节能效果有所下降;负荷降低至50%THA工况时,两级外冷器系统与回热式小汽轮机系统的节能效果相当.To solve the problem of too high superheating degree of extracted steam in 1 000 MW ultra-su- percritical （USC） units, the energy saving effect of two systems respectively with one or two steam coolers was analyzed and compared with that of the small turbine regenerative system in the case of 85% and 90% internal efficiency of the small turbine. Meanwhile, the energy saving effect was analyzed for various utilization modes of the superheating degree under different loading conditions. Results show that the energy saving effect of small turbine regenerative system is always better than that of outer cooler system under THA load condition. The energy saving effect of small turbine regenerative system increases with the rise of internal efficiency, while that of outer cooler system improves with the rise of cooler stages. When the load decreases, the energy saving effect of small turbine regenerative system declines, while that of outer cooler system rises. When the load reduces to 50% THA state, the energy saving effect of both the systems is equivalent.

关 键 词：超超临界机组 蒸汽过热度 外置式蒸汽冷却器 回热式小汽轮机 节能效果 

分 类 号：TK114[动力工程及工程热物理—热能工程]