集输管道中CO_(2)电化学腐蚀数值模拟研究

Numerical Simulation of CO_(2)ElectrochemicalCorrosion in Gathering and Transportation Pipelines

在油气集输管道内部的局部腐蚀的因素中,油气中存在的杂质(CO_(2)等)产生电化学反应是最常见的因素,其次是油气的流动条件(流速和温度等)。利用COMSOL软件建立了二氧化碳在集输管道中的综合腐蚀预测模型,综合模型包括一个管道一维模型和一个弯管三维模型,以研究最重要变量对腐蚀的影响,与实验数据吻合较好。结果表明:pH值降低和温度升高可以加快腐蚀速率,弯管表面的电位分布对腐蚀有着显著的影响。管道内外壁的腐蚀速率也有着显著差异。

Among the local corrosion factors in the oil and gas gathering and transmission pipeline,the electrochemical reaction caused by impurities(CO_(2),etc.)in the oil and gas is the most common factor,followed by the flow conditions(flow rate,temperature,etc.)of the oil and gas.In this paper,COMSOL software was used to establish a comprehensive corrosion prediction model of carbon dioxide in the gathering and transportation pipeline.The comprehensive model included a one-dimensional model of the pipeline and a three-dimensional model of the elbow to study the influence of the most important variables on the corrosion,which was in good agreement with the experimental data.The results showed that the decrease of pH value and the increase of temperature could accelerate the corrosion rate,and the potential distribution on the surface of the bend also had significant effect on the corrosion.The corrosion rate of the inner and outer walls of the pipeline was also significantly different.