PTA装置双相不锈钢管线失效分析

Failure analysis of duplex stainless steel pipe of PTA plant

PTA生产装置的PX氧化工段2205双相不锈钢设备和管线多次发生腐蚀泄漏。通过宏观分析,成分分析,金相分析,SEM扫描,EDS(色散谱)分析,对该工段泄漏原因进行分析,结果表明,管线中的乙酸蒸气和水蒸气冷凝,形成乙酸溶液并携带残渣对管壁造成冲刷腐蚀,最终造成管线的穿孔失效。

The leakages caused by corrosion happened more than once in p-xylene （PX） oxidation section of puri- fied terephthalic acid （PTA） plant production. By means of Macroscopical rupture analysis, component analysis fracture surface SEM analysis and microstructure analysis EDS analysis, the failure reasons for this PX oxidation section were analyzed. The results showed that it was the acetic acid solution formed by the condensation of acetic acid steam and water vapor flowed along bottom of tube with residue induced erosion corrosion happened in pipe line and caused the leakage finally.