超临界CO2 条件下温度对5 种典型钢腐蚀行为的影响

中石化石油工程设计有限公司· 山东省油田采出水处理及环境污染治理重点实验室

超临界CO2;含水量;温度;腐蚀产物膜

Influence of temperature on 5 typical steel corrosion behavior under supercritical CO2 condition
ZHANG Lei

SINOPEC Petroleum Engineering Corporation//Shandong Provincial Key Laboratory of Oilfield Produced Water Treatment and Environmental Pollution Control

supercritical CO2, water content, temperature, corrosion product film

备注

为获得超临界CO2 条件下温度对5 种典型钢腐蚀行为的影响规律,提高输送超临界CO2 管道的腐蚀防护效果,利用高温高压釜,采用挂片试验方法,借助扫描电镜,研究了不同温度条件下,不同不锈钢(DSS、13Cr、奥氏体钢)、碳钢(X70 钢、P110 钢)材质挂片的表面腐蚀形貌、去除腐蚀产物后金属基体表面形貌、腐蚀产物膜形成过程及挂片腐蚀速率与腐蚀产物质量之间的关系。结果 表明:水在超临界CO2 中的溶解度随压力、温度近似呈线性增加趋势;在超临界CO2 中,不锈钢的腐蚀速率比碳钢低1~2 个数量级;随着温度的增加,腐蚀产物膜对腐蚀的抑制作用超过了温度对腐蚀的促进作用,均匀腐蚀程度降低,但由于腐蚀产物膜生成过程中蜂窝状或条纹状裂纹的存在,导致挂片表面存在较严重的局部腐蚀。由此得出:超临界CO2 条件下温度对5 种典型钢腐蚀行为的影响是双向的,温度升高会减缓管材的均匀腐蚀,但也会促进管材的局部腐蚀。(图8表1,参[23]

To obtain the influence rules of temperature on 5 typical steel corrosion behavior under supercritical CO2 condition, and improve the corrosion protection effect of pipelines that are used for transporting supercritical CO2, hightemperature autoclave was adopted to conduct the coupon corrosion comparison test. With the help of scanning electron microscope, the corrosion surface morphology of different stainless steel (DSS, 13Cr and austenitic steel) and carbon steel (X70 and P110) coupons, the surface morphology of metal matrix after removing corrosion products, the formation process of corrosion product film and the relation between coupon corrosion rate and corrosion product mass were studied under different temperatures. The results indicate that the solubility of water in supercritical CO2 presents an approximately linear increase with the pressure, or temperature rise. In supercritical CO2, the corrosion rate of stainless steel is one or two orders of magnitude lower than that of carbon steel. With the temperature rise, the inhibition of corrosion product film on metal corrosion exceeds the promoting effect of temperature, resulting in a reduction in uniform corrosion. However, the existence of honeycomb or striped cracks in the formation process of corrosion product film leads to serious local corrosion on the surface of the coupon. It is concluded that the influence of temperature on 5 typical steel corrosion behavior is bidirectional under supercritical CO2 condition, in other words, the temperature rise will lower the uniform corrosion rate of pipelines, but on the other hand, it may increase the local corrosion rate. (8 Figures, 1 Table, 23 References)