Cr5Mo钢在高温环烷酸中的腐蚀研究

Study on corrosion behavior of Cr5Mo steel in High-temperature naphthenic acid

采用CJF-2L型高温高压反应釜进行旋转挂片试验,通过腐蚀失重法和腐蚀形貌分析研究了Cr5Mo钢在高温环烷酸介质中的腐蚀行为规律。试验结果表明:实验酸值、温度及流速均显著影响Cr5Mo钢的腐蚀速率。Cr5Mo钢的腐蚀速率随着介质酸值的增加而增大,与介质酸值平方根呈线性关系,但增加酸值对Cr5Mo钢的腐蚀速率影响有限;随着温度的升高,腐蚀速率先增大后减小,在280℃时腐蚀速率达到最大值,为0.262 3 mm/a,不符合Arrhenius公式;腐蚀速率随流速增加而变大,流速对腐蚀速率影响较大。Cr5Mo钢在高温环烷酸介质中出现严重点蚀,点蚀坑的数量随酸值、温度及流速增大而增大,严重威胁安全生产,因此建议Cr5Mo钢在高温环烷酸介质中应监护使用。

The CJF- 21, high -temperature and high -pressure reactor was used to proceed with rotary coupon test. Thecorrosion behavior of Cr5Mo steel in naphthenic acid medium was studied under high temperature by corrosion weight - loss method and corrosion morphology analysis. The results showed that the total acid number （TAN） , temperature and fluid velocity had a significant impact on the corrosion rate of Cr5Mo. The corrosion rate of Cr5Mo increased with rising TAN, and had a linear relationship with the square root of TAN. But the impact of increasing TAN on the corrosion rate of Cr5Mo was limited. As the temperature increased, the corrosion rate decreased after increase, and the maximum was 0. 2623 mm· a-1 at 280 ℃, but did not conform to the Arrhenius formula. The corrosion rate rose with increasing of fluid velocity, and the fluid velocity had a greater impact on corrosion rate. Cr5Mo steel in high - temperature naphthenic acid environment suffered from serious pit corrosion. The number of corrosion pits increased with increasing TAN, temperature and fluid velocity, which imposes a serious threat to safe operation. Therefore, care should be taken in the application of Cr5Mo steel in the service of high -temperature naphthenic acid medium.