汽轮机汽封改造的节能效果分析

Energy Saving Effect Analysis of Steam Seal Modification for Steam Turbine Units

介绍通流部分综合升级改造的330 MW汽轮机汽封改造方案,分析所采用蜂窝汽封、刷式汽封、接触式汽封等新型汽封的工作原理、优点和在汽轮机轴系、通流部分中适用的部位。刷式汽封在汽轮机上的应用比较广泛,高、中、低压缸各部位均适合;接触式汽封主要应用于轴端密封;蜂窝汽封用在低压缸末级、次末级叶顶部位及高、中压缸轴端。330 MW汽轮机高、中、低压缸轴端采用3种汽封相结合的方案改造后,轴封漏汽量明显减小。汽轮机高、中压后轴封漏汽量、经过轴加的凝水温升都有明显的降低;高、中压缸间平衡盘汽封漏汽量占主蒸汽流量的份额为1.02%,小于THA工况设计数据1.503%,汽封改造的节能效果显著。

Modification scheme of/low passage of two 330MW steam turbine units are introduced,as well as the operating principles and advantages of honeycomb seal, brush seal and contact seal.Application positions of these kinds of seals in rotor ends and flow passages are also introduced.Brush seal is widely used both in rotor ends and flow passages of high pressure （HP）, intermediate pressure （IP） and low pressure （LP） cylinder of steam turbine units, while contact seal is mainly used in rotor ends.Honeycomb seal is mainly used in rotor ends of HP and IP cylinder, as well as last two blade tips of LP cylinder. After modification in rotor ends of HP,IP and LP cylinder combined with the above three kinds of seals,steam leakage is decreased,of which the steam leakage from rotor ends of HP and IP is obviously decreased,leading to a lower temperature rise of condensate through gland heater.The steam leakage through balance disc from HP cylinder to IP cylinder is 1.02% of the main steam flow, which is lower than 1.503% in THA condition, showing an obvious effect of steam seal modification.