针对600 MW超临界抽凝式供热机组投运后，因汽轮机通流部分效率低，导致电厂能耗高等问题，由东方汽轮机有限公司优化设计汽轮机通流部分的汽封，电厂利用机组大修机会，全部换新高压缸、中压缸和低压缸的叶顶汽封，并且逐一对各通流汽封间隙进行优化。在简要介绍1号机组设备的基础上，结合电厂实际，通过分析与比较，实施第三种汽封优化改造方案。经过机组热力性能试验，修正后热耗率下降值为166 kJ/kWh，表明优化措施合理可行，提高了机组的热效率。如果1号纯凝供热机组年发电量按33亿kWh、到厂标煤按900元/t计算，年节约标准煤为1.869万t，年节约费用为1 682万元，经济效益十分显著，达到了节能降耗的目的。

The deficiency in the efficiency of turbine flow path leads to a high energy loss in the 600 MW supercritical power &heat cogeneration plant. An optimization plan on the loop seal was proposed by Dongfang Steam Turbine Co., Ltd. The original blade-top loop seals in the high-, intermediate- and low- pressure steam turbine were replaced, and each gap of the loop seal was individually optimized in the power plant maintenance. Based on the induction of 1# Unit, the third optimization program was adopted according to the actual plant conditions. After the thermal performance test of the unit, the amended heat rate decreases to 166 kJ/kWh, revealing the optimization could increase the thermal efficiency of the unit. The economic benefit is significant. The condensing Unit 1# could save 18,690 ton standard coal per year, totally 16.82 million yuan with a generated electricity 3.3 billion kilowatt hours and a coal price of 900 yuan per ton. The energy saving purpose is achieved.