气体流速对含CO_(2)天然气湿气管道腐蚀速率的影响

Effect of Gas Velocity on Corrosion Rate of Wet Gas Pipeline Containing CO_(2)

以某CO_(2)含量为5.2%的气田采出气为研究对象,通过PREDICT软件模拟研究了对于管径为DN150的5km水平管段,当末端压力为3MPa、起始端温度为16℃时,气体流速大小对管道的内腐蚀速率及其腐蚀机理的影响。结果表明,当管道起始端介质流速小于1.85m/s时,管道的内腐蚀速率随气体流量的增加而减小,此时管道的腐蚀机理主要为电偶腐蚀;当管道起始端介质流速大于1.85m/s时,管道内腐蚀速率随着流速的增加而增大,此时管道的内腐蚀主要受管道内流型的变化、传质作用及流体介质对腐蚀产物膜的冲刷作用等因素控制;将挂片腐蚀测量结果与软件计算结果对比发现PREDICT软件有较高的计算精度。

Taking the produced gas from a gas field with a CO_(2)content of 5.2% as the research object,this paper simulates and studies the influence of gas velocity on the internal corrosion rate and corrosion mechanism with a pipe diameter of DN150 horizontal pipeline section when the terminal pressure is 3MPa and the initial temperature is 16℃.The results show that when the flow velocity at initial of the pipeline is less than 1.85m/s,the internal corrosion rate of the pipeline decreases with the increase of gas flow.At this time,the corrosion mechanism of the pipeline is mainly galvanic corrosion;when the flow velocity at initial of the pipeline is greater than 1.85m/s,the corrosion rate in the pipeline increases with the increase in flow velocity.At this time,the internal corrosion of the pipeline is mainly affected by the change of the flow regime in the pipeline,the mass transfer effect,and the fluid medium controlling factors such as the erosion effect of the corrosion product film;comparing the measurement results of coupon corrosion with the calculation results of the software,it is found that the PREDICT software has higher calculation accuracy.