超超临界机组高压主汽门卡涩原因分析及防范措施  

Analysis and preventive measures of high pressure main valve jam of ultra supercritical unit

作　　者：李宏卫 王广涛 姜占文 LI Hong-wei;WANG Guang-tao;JIANG Zhan-wen

机构地区：[1]河北国华定洲发电有限责任公司,河北保定071003

出　　处：《节能》2020年第12期97-99,共3页Energy Conservation

摘　　要：某电厂新型660 MW汽轮机机组投入运行半年后出现高压主汽门卡涩现象,活动试验时不动作或动作不到位。为分析高压主汽门卡涩原因,对其解体检查,发现阀碟和衬套表面有大量氧化层剥落。借助扫描电镜(SEM)对采集的脱落物进行检测。研究结果表明:脱落中颗粒物所含的元素主要是Fe和O,并含有C及少量杂质元素。结合形貌特征和能谱测试结果,分析得到细小颗粒状脱落物主要成分为部件表面的氧化物;阀内部存在杂质元素加速了阀内部的氧化速度,导致衬套内氧化皮堆积造成高压主汽门卡涩。通过对汽门阀杆进行超音速火焰喷涂、阀芯表面及阀芯套内表面喷焊司太立合金抗氧化处理以及机组在运行期间按照每月进行一次阀门全行程活动性试验,可避免氧化皮堆积。A power plant’s new 660 MW steam turbine unit was put into operation for half a year, and the high-pressure main valve jam occurred, and it did not operate or did not operate properly during the activity test. In order to analyze the cause of the jam of the high-pressure main valve, it was disassembled and inspected, and it was found that a large amount of oxide layer was peeled off on the surface of the valve disc and bushing. Scanning electron microscopy(SEM) was used to detect the collected falling objects. The research results show that the main elements contained in the particles in the shedding are Fe and O, and contain C and a small amount of impurity elements. Combining the morphology characteristics and energy spectrum test results, the analysis shows that the main component of the fine particulate shedding is the oxide on the surface of the component;the presence of impurity elements in the valve accelerates the oxidation rate inside the valve, resulting in the accumulation of oxide scale in the bushing, and high pressure main steam, where the door is stuck.By supersonic flame spraying on the valve stem, spray welding of Stellite alloy anti-oxidation treatment on the surface of the valve core and the inner surface of the valve core sleeve, and a monthly valve full stroke activity test during the operation of the unit, oxide scale can be avoided accumulation.

关 键 词：高压主汽门 卡涩 杂质元素 司太立合金 氧化皮 

分 类 号：TK2[动力工程及工程热物理—动力机械及工程]