常减压蒸馏装置塔顶腐蚀案例分析与控制

Case Study of Overhead Corrosion of Atmospheric-vacuum Distillation Unit and Control

随着国内炼油厂所加工原油密度、酸值和硫含量的不断升高,常减压蒸馏装置的初馏塔、常压塔及减压塔冷凝冷却系统的腐蚀也不断加重。由于塔顶冷凝冷却系统材质以碳钢为主,致使设备腐蚀严重,甚至过早失效,严重影响装置的长周期安全运转。目前在新建常减压蒸馏装置的设计选材上大量选用316L奥氏体不锈钢、双相不锈钢和钛材等高等级材料。文章通过对两个炼油企业常压塔顶干空冷器腐蚀穿孔、初馏塔顶油/原油换热器开裂和常压塔顶三剂注入口附近酸露点腐蚀三个失效案例的分析,找出了失效原因,给出了建议改进措施。

With increasing density, acidity value and sulfur of crude oils processed in China domestic refineries, the condensation systems in preliminary towers, atmospheric towers and vacuum towers of the atmospheric - vacuum distillation units are suffering deteriorating corrosion. As the materials in the overhead condenser system are carbon steels, the equipment corrode rapidly or even fail before the end of service life. This has affected the long - term and reliable operation of the unit. Now, the grass - roots atmospheric - vacuum distillation units have mostly selected 316L austenitic steel, duplex steel and Ti material etc. Through the case study of corrosion failures in the overhead air cooler of atmospheric tower, cracking of overhead oil/crude oil heat exchanger of preliminary tower and acid dew point corrosion at the inlet of inhibitor injection at the overhead of atmospheric tower, the causes of corrosion failures are located and improvement measures are proposed.