多相流动下温度、氯离子浓度及CO_2分压对X60钢腐蚀的影响  

Analysis of Effects of Temperature, Cl^- Concentration and CO_2 Partial Pressure on Multiphase Flow Corrosion of X60 Steel

作　　者：郎一鸣 李显超[2] 王庆 胥锟 

机构地区：[1]中海石油(中国)有限公司,上海200030 [2]中国船舶重工集团公司第七二五研究所青岛分部,山东青岛266101 [3]中国石油大学(华东)储运与建筑工程学院,山东青岛266580

出　　处：《石油工程建设》2015年第6期82-86,共5页Petroleum Engineering Construction

基　　金：国家科技重大专项(2011ZX05017-004)资助

摘　　要：利用自制高低起伏管路模拟腐蚀实验装置,研究了在起伏管路多相流冲刷作用下,不同温度、氯离子浓度和CO_2分压对X 60管线钢的腐蚀速率、腐蚀形态以及腐蚀产物膜形貌的影响。结果表明:随着温度的增加,试样腐蚀速率呈先逐渐增大后逐渐减小趋势,在65℃左右出现峰值;较低温度时,试样表面局部覆盖少量腐蚀产物膜,冲蚀协同作用造成试样表面产生严重的点蚀、沟槽状腐蚀等;温度较高时试样表面产物膜覆盖增多增厚,其对基体的保护作用越来越强,腐蚀速率降低,局部腐蚀特征不明显。随着氯离子浓度的增大,试样腐蚀速率呈先增大后下降又逐渐上升趋势;浓度较低时,多相流动冲刷剪切力造成表层剥离,加剧材料质量损失;浓度较高时,表面产物膜厚且疏松,产生了点蚀或坑蚀等。随着CO_2分压的增加,试样腐蚀速率呈先逐渐增大后减小的趋势;较小分压下基本上形不成产物膜;中等分压下生成的产物膜致密性和厚度增大,但是与基体的结合力较小,产物膜的破坏脱落严重,腐蚀速率较大;较大分压下生成的产物膜较厚且致密,对基体的保护性增强,腐蚀速率较低。A simulation test device for multiphase flow in rolling pipelines is used to study the effects of multiphase flow erosion on CO_2 corrosion rate of X60 steel, corrosion appearances and morphologies of superficial corrosion scale under conditions of different temperature, CI concentration and CO_2 partial pressure. The results show that： （ 1 ） As the temperature increases, the corrosion rate of the sample increases at first and then de- creases gradually with a peak value at about 65 ℃. When the temperature is low, the surface of sample is partly covered with a small amount of corrosion scale and the erosion synergy leaves severe local corrosion morphologies on the surface of the sample such as pitting corrosion and grooving corrosion ;（ 2 ） With the increase of CI- concentration, the corrosion rate of the sample firstly increases and then decreases which is followed by another gradual increase. When the concentration is low, the shearing force generated by multi- phase flow erosion leads to the surface layer stripping and aggravates the mass loss of material. And when the concentration is high, the superficial corrosion scale is thick and loose with local corrosions such as pitting corrosion and pointed corrosion; 〈 3 ） With the increase of CO_2 partial pressure, the corrosion rate of the sample firstly increases and then decreases. The corrosion scale is hardly formed under small partial pressure. And the corrosion scale formed under medium partial pressure has a larger compactness and thickness whose adhesion to the substrate is so small that the damage and abscission of the scale is serious and the corrosion rate is comparatively large. The corrosion scale formed under greater partial pressure tends to be thicker and more compact which has a good protection for the substrate, and the corrosion rate is smaller.

关 键 词：多相流 X60钢 腐蚀 CO_2分压 温度 氯离子浓度 

分 类 号：TE980.1[石油与天然气工程—石油机械设备]