某塔式锅炉异常振动现象及原因分析

Abnormal Vibration Phenomenon and Cause Analysis of a Tower Boiler

根据发生区域的不同,对锅炉振动进行分类,并指出各区域诱发振动的可能原因。某塔式锅炉异常振动的出现周期及发生部位无统一规律,由测试得知燃烧脉动频率为2~5 Hz,垂直于炉膛法向的一阶声学频率为14~18 Hz,结合热态检查可排除热声振动、燃烧脉动、局部刚性差等原因。锅炉出现冲击振动时,计算炉墙瞬时冲击作用压力为220~366 Pa。实际炉膛低负压运行时波动变化范围为-450~150 Pa。通过燃烧数值模拟发现,不同摆角条件下,炉内CO分布存在很大差异。燃烧动力场组织不当会导致CO富集,当CO聚集到一定浓度并与氧气混合后,易发生局部爆燃,锅炉出现异常振动。

This paper classifies the boiler vibration according to different areas,and points out the possible causes of vibration in each area.There is no unified rule for the occurrence period and position of abnormal vibration of a tower furnace.The results show that the frequency of combustion pulsation is mainly 2~5 Hz,and the first-order acoustic frequency perpendicular to the normal direction of the furnace is 14~18 Hz.Combined with the thermal state inspection,the causes of thermoacoustic vibration,combustion pulsation and local stiffness difference can be eliminated.When the impact vibration occurs in the boiler,the calculated instantaneous impact pressure of the furnace wall is 220~366 Pa.The fluctuation range of actual furnace in low negative pressure operation is between-450 Pa and 150 Pa.Through the combustion numerical simulation,it is found that there are great differences in CO distribution in the furnace under different swing angles.If the combustion power field is not well organized,co will be enriched.When the concentration of CO is accumulated to a certain level and mixed with oxygen,local deflagration will occur and abnormal vibration will appear in the boiler.