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目的 预测输气金属管道表面腐蚀速率.方法 分析动态杂散电流和二氧化碳(CO2)浓度对金属管道的表面腐蚀机理,给出金属管道表面腐蚀产生的化学反应方程式.根据一元回归线性方程式得出多元线性回归数学方程式,推导出动态杂散电流和CO2腐蚀金属管道表面方程式,得出金属管道表面腐蚀预测的最终模型.结合具体实例,采用数学软件MATLAB对45号金属管道表面腐蚀速率预测的多元线性回归模型进行仿真,并且与实验测量的腐蚀速率进行比较和分析.结果 金属管道表面的腐蚀速率随着动态杂散电流或者CO2浓度的增大而逐渐增大.在100 h内,电流和CO2浓度仿真的金属管道表面最大腐蚀速率分别为3.72×10–4 mm/h和4.80×10–4 mm/h,电流和CO2浓度仿真的金属管道表面最小腐蚀速率分别为3.26×10–4 mm/h和4.24×10–4 mm/h,电流和CO2浓度实验测量的金属管道表面最大腐蚀速率分别为3.76×10–4 mm/h和4.86×10–4 mm/h,电流和CO2浓度实验测量的金属管道表面最小腐蚀速率分别为3.12×10–4 mm/h和4.08×10–4 mm/h.同时,金属管道表面腐蚀速率理论计算值与实验测量值的相对误差在5%以内.结论 采用多元线性回归模型可以近似预测输气金属管道表面的腐蚀速率,为管道的使用寿命提供参考数据,避免输气金属管道发生重大安全事故.

The work aims to predict surface corrosion rate of metallic gas pipeline. Surface corrosion mechanism of dynam-ic stray current and carbon dioxide (CO2) concentration on metallic pipelines was analyzed to present chemical reaction equation of surface corrosion of the metallic pipelines. Multiple linear regression equation was obtained based on simple linear regression equation, then metal pipe surface equation of dynamic stray current and CO2 corrosion was further derived, and the final model for corrosion prediction of metal pipe surface was obtained. Based on the specific examples, the multiple linear regression model for surface corrosion rate prediction of 45 metallic pipelines was simulated by mathematical software MATLAB, and the corro-sion rate was compared and analyzed by comparing with the experimental measurement. The corrosion rate of metallic pipeline surface increased with the increase of the dynamic stray current or CO2 concentration. Within 100 h, maximum corrosion rate of metallic pipeline surface with simulated current and CO2 concentration was 3.72×10–4 mm/h and 4.80×10–4 mm/h respectively, and the minimum 3.26×10–4 mm/h and 4.24×10–4 mm/h respectively. Maximum corrosion rate of metallic pipeline surface in current and CO2 concentration experimental measurement was 3.76×10–4 mm/h and 4.86×10–4 mm/h respectively, and the min-imum 3.12×10–4 mm/h and 4.08×10–4 mm/h respectively. Meanwhile, the relative error between the theoretical value and the experimental value was less than 5%. The multiple linear regression model can be used to predict corrosion rate of the surface of the metallic gas pipelines approximately, providing reference data for the service life of pipelines and preventing major safety accidents of metallic gas pipelines.