摘要
针对中国石化3家百万吨乙烯企业采用加氢尾油原料时乙烯裂解炉管焊缝腐蚀泄漏问题开展了试验室解剖分析、腐蚀模拟试验、流场模拟研究工作。结果表明,腐蚀部位主要位于25Cr35NiNb材质的入口管下部焊缝处,发生腐蚀焊缝大多采用Inconel 82焊丝焊接,腐蚀速度快,呈烧蚀状,一般几天至几个月;该腐蚀为选择性腐蚀,腐蚀严重部位发生穿孔,沿腐蚀边缘有一层致密氧化层,氧化层与基体之间或局部优先沿晶腐蚀的晶界上含硫元素,腐蚀产物中含S,Cl,Na等元素;推断成分为镍基或者高镍材质焊缝处发生的乙烯裂解炉管腐蚀泄漏是由熔盐腐蚀导致的,熔盐成分主要为Na_2SO_4+NaCl。此外,还就如何避免或者减缓该类腐蚀提出了建议。
In order to study the problem of corrosion and leakage of ethylene pyrolysis furnace tube in 3 million-tons ethylene enterprises of Sinopec,the laboratory test and corrosion simulation test were carried out. Results show that corroded weld seam was mainly located at the lower inlet of 25Cr35NiNb tube. Most of the corrosion weld seams were welded with Inconel 82 welding wire. The corrosion rate was rapid,perforation could be occurred in a few days to several months,and erosion was in the form of ablation. It was a selective corrosion,and a layer of dense oxide was found along the edge of the corrosion. The corrosion products contained S,Cl,Na and other elements,it was also found S between the oxide layer and the matrix or the grain boundary which was caused by intergranular corrosion. It is concluded that the corrosion of nickel-based or high-nickel material weldments of ethylene pyrolysis furnace tube was caused by molten salt corrosion,and the main component of molten salt was Na2SO4＋ NaCl. In addition,recommendations were offered on how to avoid or mitigate such corrosion.
出处
《压力容器》
2017年第11期61-69,共9页
Pressure Vessel Technology
基金
国家重点研发计划(2017YFF0210402)
关键词
裂解炉管
焊缝
失效
加氢尾油
腐蚀
ethylene pyrolysis furnace tube
weld seam
failure
hydrogenation residual oil
corrosion
