液固两相流中Q235钢的冲刷腐蚀行为研究

Investigation on Erosion-Corrosion Behavior of Q235 Steel in Liquid-Solid Flow

随着原油中含砂量的迅速增加,冲蚀腐蚀逐渐成为管道失效的关键因素,尤其是弯头部位。因此通过腐蚀速率、腐蚀形貌和电化学实验研究90°弯头的冲刷腐蚀行为。结果表明,随着实验时间的增加,Q235钢在不同角度的腐蚀速率呈线性增加,而最大点蚀深度基本保持不变。在进口θ=0°~45°,Q235钢受到冲刷和冲击的共同作用,随着角度的增大,Q235钢表面腐蚀产物层的破碎程度越来越严重;在出口θ=45°~90°,Q235钢仅受冲刷影响,腐蚀产物和孔洞的分布具有明显的方向性。在该文研究的条件下,纯冲蚀电流密度仅为冲蚀-腐蚀电流密度的42.16%,原因主要是疏松的FeO(OH)对电化学过程有促进作用,同时也能加速产物的扩散。

With the rapid increase of sand content in crude oil,erosion corrosion has gradually become the key factor of pipeline failure,especially for the elbows.In this paper,the corrosion rate,corrosion morphology and electrochemical experiment were investigated to study the erosion-corrosion behavior of 90°elbow.The results showed that with the increase of experiment time,the corrosion rate of Q235 steel at different angles increased linearly,while the max pitting depth basically remained unchanged.In the inlet section ofθ=0°~45°,Q235 steel was subjected to the joint action of erosion and impact.With the increase of angle,the breakage degree of corrosion product layer on Q235 steel surface became more serious.In the outlet section ofθ=45°~90°,Q235 steel was only affected by erosion,and the distribution of corrosion products and holes had obvious directionality.The pure erosion process can be divided into three stages of the formation of erosion morphology,development in the longitudinal direction and general erosion.Under the conditions studied in this paper,the current density of pure erosion was only 42.16%of that of erosion-corrosion.The reason was mainly that the loose FeO(OH)can promote the electrochemical process and also accelerate the diffusion of products.