蜡油加氢装置的电化学腐蚀与防护

Electrochemical Corrosion in Wax Oil Hydrotreating Unit and Protection

中国石油化工股份有限公司洛阳分公司220×104t/a蜡油加氢处理装置在第一运行周期装置的出现腐蚀主要包括高温氢腐蚀、氢脆、奥氏体不锈钢堆焊层的氢致剥裂、高压空冷器低流速的部位由于NH4Cl和NH4HS浓缩结垢,造成电化学垢下腐蚀,形成蚀坑,最终形成穿孔、轻油部位湿硫化氢的腐蚀、由敏化不锈钢制造的设备装置停工期间的连多硫酸腐蚀、硫酸露点腐蚀等,通过定点测厚、腐蚀挂片、腐蚀介质分析,通过优化工艺参数和操作条件、必要的材质升级、注入环缓蚀剂以及进行腐蚀检测等措施解决的蜡油加氢装置腐蚀问题。

The corrosions in a 2.2 MM TPY wax oil hydrotreating unit in SINOPEC Luoyang Company were found in the scheduled overhaul after 1st operating cycle.The corrosions mainly include high-temperature hydrogen corrosion,hydrogen brittling,hydrogen induced cracking（HIC） of stainless steel deposit weld,electrochemical under-deposit corrosion,pit corrosion and corrosion failures due to fouling condensation of NH4Cl and NH4HS at the low-velocity locations of HP air coolers,wet hydrogen sulfide corrosion in light oil service,polythionic acid corrosion and sulfuric acid dew point corrosion of sensitive stainless steel equipment,etc.The corrosions in the unit have been brought under control after optimization of process parameters and operating conditions,necessary material upgrading,injection of corrosion inhibitors and implementation of corrosion testing based upon positioned thickness measurement,coupon testing and corrosive media analysis.