Abstract: The carbon steel pipeline of the dehydrogenation tail gas system in a certain styrene unit has a thinning rate of 55.51% and a corrosion rate of up to 5.29 mm/a after one year of use, which restricts the long-term stable operation of the plant. The corrosion of the dehydrogenation tail gas carbon steel pipeline was inspected through electromagnetic eddy current scanning, ultrasonic thickness measurement, and macroscopic inspection. The impact of corrosive medium, process operating parameters, on-site pipeline location, and material on pipeline thinning in the dehydrogenation tail gas system was analyzed. The results indicate that the localized corrosion and thinning of the dehydrogenation tail gas carbon steel pipeline are caused by a combination of carbon dioxide corrosion and erosion corrosion under certain temperature and pressure. To alleviate corrosion issues, it is recommended to re-evaluate the process operating conditions of the dehydrogenation tail gas system, add cooling equipment before the dehydrogenation tail gas compressor, or upgrade the pipeline material to 304 austenitic stainless steel; consider adding corrosion inhibitors to the dehydrogenation tail gas system; regularly carry out electromagnetic eddy current scanning or ultrasonic thickness measurement to monitor the relevant pipelines and prevent leaks in a timely manner.

Key words: font-family:-apple-system, blinkmacsystemfont, ", font-size:14px, background-color:#FFFFFF, ">styrene unit, dehydrogenation tail gas, carbon steel pipeline, thinning, ultrasonic thickness measurement, eddy current scanning, corrosion inspection, carbon dioxide corrosion

摘要： 某苯乙烯装置脱氢尾气系统碳钢管线使用１ａ后减薄率为５５．５１％，腐蚀速率高达５．２９ｍｍ／ａ，制约了装置的长周期安稳运行。通过电磁涡流扫描、超声测厚、宏观检查对脱氢尾气碳钢管线的腐蚀情况进行了检查，分析了脱氢尾气系统的腐蚀性介质，工艺运行参数，现场管线位置、材质对管道减薄的影响。结果表明：脱氢尾气碳钢管线的局部腐蚀减薄是在一定的温度、压力下，由二氧化碳腐蚀和冲刷腐蚀共同导致的。为缓解腐蚀问题，建议：重新评估脱氢尾气系统的工艺操作条件，在脱氢尾气压缩机前增设冷却设备，或者升级管线材质为３０４奥氏体不锈钢；考虑在脱氢尾气系统加注缓蚀剂；定期采取电磁涡流扫描或超声测厚对相关管线进行监控，及时防止泄漏发生。

关键词: font-family:-apple-system, blinkmacsystemfont, ", font-size:14px, background-color:#FFFFFF, ">苯乙烯装置, 脱氢尾气, 碳钢管道, 减薄, 超声测厚, 涡流扫描, 腐蚀检查, 二氧化碳腐蚀