Analysis and Treatment of Shaft Sealing Problems in 1 000-MW Double Reheat Turbines

doi:10.11930/j.issn.1004-9649.2017.01.101.04

Abstract

Abstract: The successful commissioning of Taizhou No.3 unit indicates the start of the commercial operation of the million kilowatt coal- fired generating units with the double reheat system. While the operating parameters appear good, the unit has yet some problems such as low gland seal steam temperature during debugging, low shaft seal steam pressure, large shaft seal steam temperature, pressure fluctuations after tripping, and high VHP exhaust steam temperature due to sealing steam reversed flow. Aiming at these problems, detailed analysis is conducted, which concludes that they are attributed to the high exhaust steam temperature, the large shaft seal steam leakage, the dreadful atomization effect of shaft seal attempering water, the shaft seal steam temperature control logics inconsistency with the double reheat system and the lack of check valve on the outlet pipe from the first shaft seal of the VHP cylinder. Following the analysis, corresponding solutions are put forward, including installing electric heaters, improving the atomization nozzle, modifying the temperature control logics and equipping check valves, hoping to help better operating the same and similar units in the future.

Key words: ultra-supercritical unit, double reheat, steam turbine, shaft seal system, shaft seal steam temperature, shaft seal attempering water

CLC Number:

TM621

XUE Jiangtao, ZHANG Yaohua, MA Yunxiang, DING Jianliang. Analysis and Treatment of Shaft Sealing Problems in 1 000-MW Double Reheat Turbines[J]. Electric Power, 2017, 50(1): 101-104.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.2017.01.101.04

https://www.electricpower.com.cn/EN/Y2017/V50/I1/101

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