加热炉炉管局部腐蚀及防治

The Local Corrosion of Furnace Tube of Heater and Its Countermeasures

加热炉炉管是直接式加热炉的关键部件,其壁厚直接影响加热炉的安全运行。分别对方箱炉和弹簧炉的炉管壁厚进行了测试,从分析数据得出结论:炉内单根炉管的腐蚀主要集中在炉管两头及靠近弯头部位0～900mm范围内;炉管局部腐蚀严重的部位主要集中在炉墙的8个角区,其中炉墙前侧的4个角区最为严重。通过对加热炉炉管局部腐蚀现象进行剖析,指出腐蚀主要是炉管上灰垢中的硫酸分子和凝析在炉管上的水滴形成了酸性腐蚀所致,提出了炉管局部腐蚀的防治措施及大修时对局部腐蚀炉管的处理意见。

The furnace tubes are the vital components in direct fired heater. The wall thickness of the tube has direct relations to the safe operation of heater. The thickness measurements had been respectively made for the box-like type and spring type heaters,the results showed that inside the heater,the corrosion on the individual straight tube mainly centred around its two ends which closed to the bends within the range of 0-900 mm,the more serious local corrosion of the tube mainly centred at the 8 corners of the wall,and the 4 among them on the front side of the wall are the most serious. Through analyzing on the corrosion,it is considered that the corrosion is a kind of sour corrosion resulted from the sulphuric-acid molecules in the soot combined with water droplet condensed on the tube. The countermeasures against the corrosion and overhaul program are proposed.