›› 2018, Vol. 49 ›› Issue (7): 63-68.

• 设备及防腐 • 上一篇    下一篇

氮气保护下炼化企业停用装置的腐蚀行为研究

牛鲁娜1,兰正贵1,李伟华2,宋晓良1,屈定荣1   

  1. 1. 中石化青岛安全工程研究院
    2. 中国石化普光分公司
  • 收稿日期:2017-11-14 修回日期:2018-01-09 出版日期:2018-07-12 发布日期:2018-07-26
  • 通讯作者: 牛鲁娜 E-mail:niuln.qday@sinopec.com

RESEARCH ON THE CORROSION BEHAVIOR IN NITROGEN PROTECTION ATMOSPHERE FOR SHUTDOWN EQUIPMENT OF REFINING AND PETROCHEMICAL PROCESS UNITS

  • Received:2017-11-14 Revised:2018-01-09 Online:2018-07-12 Published:2018-07-26

摘要: 模拟停工装置内潮湿环境,对20号钢、16MnR、Cr5Mo和304不锈钢等4种典型材质,在氮气置换保护条件下的腐蚀进行试验,考察了不同氧含量对4种材质腐蚀的影响。利用挂片失重法、3D腐蚀轮廓仪和XRD等手段对腐蚀试样进行了腐蚀速率分析、腐蚀形貌观察和腐蚀产物组成分析。结果表明:气相潮湿环境下,随着氧含量的增加,碳钢腐蚀速率先降低后平稳增加,Cr5Mo和304不锈钢的腐蚀速率均稳定保持在较低的水平;液相环境下,当氧体积分数大于1.0%时碳钢和铬钼钢腐蚀速率有升高的趋势;氧体积分数0.5%~1.0%时各材质在气液两种环境下的腐蚀速率相差不大;碳钢和铬钼钢的宏观形貌基本一致,腐蚀产物主要是疏松的γ-FeOOH和致密的Fe3O4,金属基体腐蚀表现为蚀坑和溃疡状腐蚀;304不锈钢未见明显腐蚀,仍保持金属光泽。选取某企业停工装置的典型部位进行了周期114天的现场挂片实验,结果表明,在氧体积分数0.5%的情况下,各部位停工保护效果良好。

关键词: 腐蚀, 停用装置, 氮气保护, 氧含量

Abstract: The corrosion behaviors of four typical materials in nitrogen protection atmosphere were studied in the simulated wet environment. The corrosion rate, corrosion appearance and the composition of corrosion products were investigated through weight-loss method profilometry and X-Ray diffraction (XRD), respectively. The results show that, in the gas phase, the trend of corrosion rate for two kinds of carbon steel decrease followed by a steady increase with the increasing of oxygen content; The Cr5Mo and 304 stainless steel both maintain stably at a low level. In the liquid phase, the corrosion rates of carbon steel and chromium-molybdenum steel increase obviously when oxygen content reaches to 1.0%. There is small difference of material corrosion rates when the oxygen content changes in the range of 0.5%~1.0% in both gas and liquid phase. The corrosion characteristics of carbon steel and chromium-molybdenum steel are basically the same. The corrosion products mainly consist of γ-FeOOH and Fe3O4, with metal ulcerated and etched. The 304 stainless steel still maintains the metallic luster and has no obvious corrosion.