黄坤昌 范双双 李丰均 居国腾 刘东旭

摘  要：轴封系统是汽轮机的重要子系统，直接影响机组的安全性和经济性。某电厂300MW机组在完成切缸改造工作后，汽轮机轴封加热器水位产生了持续波动且逐渐恶化，导致轴封加热器频繁推出运行状态。通过制订不同的试验方案逐步排除了各部位的漏汽问题或切缸引发的副作用，并发现了疏水超过管道承载能力是造成水位波动的主要原因。通过改造疏水管路以增加轴加疏水的溢流能力有效解决了该故障。改造方案对同类型机组的类似问题有一定的借鉴意义。

关键词：300MW汽轮机组 轴封系统 轴封加热器 水位波动 低压缸切除

中图分类号：TM621 文献标识码：A 文章编号：1674-098X（2021）07（a）-0048-04

Cause Analysis and Solving Measures of Shaft Seal Heating Water Level Fluctuation of 300MW Steam Turbine

HUANG Kunchang1  FAN Shuangshuang2，3  LI Fengjun1  JU Guoteng1  LIU Dongxu2，3*

（1. Zhejiang Zheneng Shaoxing Binhai Thermal Power Co.， Ltd， Shaoxing， Zhejiang Province， 312073 China;2. Harbin Institute of Technology， Harbin， Heilongjiang Province， 150001 China;

3. Harbin Wohua Intelligent Power Equipment Co.， Ltd.， Harbin， Heilongjiang Province， 150001 China）

Abstract： The shaft seal system is an important subsystem of the steam turbine， which directly affects the safety and economy of the unit. After a 300MW unit completed the modification of removing low-pressure cylinder， the water-level of the shaft seal heater fluctuated continuously and gradually deteriorated， which caused the gland heater to be frequently put out of operation. Through the development of different test programs， the steam leakage problem at various parts or the side effects caused by removing low-pressure cylinder were gradually eliminated， and it was found that the drainage exceeding the carrying capacity of the pipeline was the main reason for the fluctuation of the water level. The fault was effectively solved by modifying the drain pipeline to increase the overflow capacity of the gland heater drain. The transformation plan has certain reference significance for similar problems of the same type of units.

Key Words： 300MW steam turbine; Shaft seal system; Shaft seal heater; Water level fluctuation; Low pressure cylinder removing

在电厂机组运行的过程中，轴封系统是汽轮机系统中的一个重要子系统[1，2]，主要用于对汽轮机动静结合部位的密封，其中轴封加热器起着关键作用[3，4]。但轴封加热器会发生水位波动问题，其原因很多：轴封加热器管系泄漏或爆管[5]、汽轮机润滑油中带水[6]、多级水封均运行不稳而发生水封破壞[7]、轴封加热器疏水不畅导致多次满水[8]等。为此，一些学者对轴封水位波动现象进行研究，针对不同的原因提出改造方案。主要有以下方案：合理调整轴封供汽压力[9];改造轴封管路，增设高压汽封加热器[10];修正最初的计算数值，合理选择多级水封的高度[11];汽轮机轴封排汽管道上设置U型紧急排水口[12]。

本文将针对某电厂300MW机组轴封加热器水位波动现象展开分析，其中对轴封加热器的额定参数、U型管水封高度、U型管疏水能力等方面进行分析。……