含CO2油气管道内腐蚀模拟及剩余寿命预测

目的通过对含CO_2油气管道的内腐蚀状况进行仿真和实验研究,得出管道的内腐蚀规律和剩余使用寿命。方法以渤西海域某一管道的实际工况为基础,采用OLGA软件并选择De Waard95模型对CO_2腐蚀速率的影响因素进行仿真分析。采用失重实验研究了温度和CO_2分压对X52级管道钢腐蚀速率的影响,在仿真数据的基础上对腐蚀管道的剩余寿命进行预测。结果仿真结果表明,管道沿线的温度、压力、持液率、流型及pH值对CO_2腐蚀程度的影响都很大。实验发现,CO_2腐蚀速率随温度的升高呈先增后降的趋势,且在温度为333 K时达到最大值,为0.22 mm/a。随着CO_2分压的升高,腐蚀速率呈上升趋势,最大值为0.24 mm/a。结论随着管道高程和里程的不同,不同因素对CO_2腐蚀有不同程度的影响,管道入口段的腐蚀速率最大,仿真和实验结果对管道的内腐蚀防护和剩余寿命预测有一定的参考价值。

Corrosion Simulation inside Oil-Gas Pipelines Containing CO2 and Prediction of Residual Life

The work aims to conclude the internal corrosion law and residual service life of pipelines by means of the simulation of and the experimental study on the internal corrosion of oil-gas pipelines containing CO2. Based on the actual working conditions of some pipe in the western area of the Bohai Sea, OLGA software and De Waard95 model were selected to simulate and analyze the factors influencing CO2 corrosion rate. Weight loss experiment was adopted to research the effect of temperature and partial pressure of CO2 on the corrosion rate of X52 pipeline steel. The residual service life of corroded pipelines was predicted based on the simulation data. The simulation results showed that the temperature, pressure, liquid holdup, flow pattern and pH value along the pipelines had great influence on CO2 corrosion rate. Experiment showed that: with the increase in temperature, CO2 corrosion rate increased firstly and then decreased. The maximum corrosion rate reached 0.22 mm/a at 333 K. Corrosion rate increased with the increase in CO2 partial pressure, and the maximum value was 0.24 mm/a. With the change in piping elevation and mileage, different factors have different degrees of impact on CO2 corrosion. The corrosion rate of pipelines inlet section is the largest. The results of simulation and experiment provide certain reference value for internal corrosion protection and prediction of residual service life of the pipelines.