高酸原油对减压系统腐蚀的影响

中海油惠州炼化分公司按加工高酸低硫原油设计，常减压蒸馏装置防腐设计主要针对环烷酸引起的腐蚀和塔顶冷凝冷却系统的腐蚀。常减压装置减压系统高温部位控制腐蚀的主要措施包括采用高的材质等级、加注高温缓蚀剂和控制流速流态避开严重腐蚀区。低温部位控制腐蚀的措施主要包括加注中和缓蚀剂、控制好适宜的操作条件，同时通过设备管道腐蚀在线监测系统加强对腐蚀的监控。常减压蒸馏装置减压系统经过3a的运行，腐蚀控制良好。减顶出现较严重的小分子有机酸腐蚀，减二线腐蚀速率较高。对于小分子有机酸的腐蚀、减压塔填料的腐蚀、减二线腐蚀问题进行了分析并提出相应的改进措施。

Impact of high-TAN crude oil to corrosion of vacuum oistillation system

CNOOC Huizhou Refinery was designed to process crude oil with high total acid value （TAN） and low sulfur. The anticorrosion design of the crude distillation unit mainly focuses on the corrosion by naphthenic acid and corrosion in tower overhead condensing and cooling systems. For the vacuum distillation system, the main measures to control the corrosion in high temperature locations are the application of high - grade materials, injection of high - temperature corrosion inhibitor and control of flow rate and flow pattern to avoid serious corrosion area. In the low -temperature sections, the anti - corrosion measures mainly include injection of neutralization corrosion inhibitor and control of the appropriate operating conditions while on - line corrosion monitoring system is provided to monitor and control the corrosion of equipment and pipelines. The corrosion has been effectively controlled in 3 years＇ operation of vacuum distillation system in atmospheric - vacuum distillation unit. Serious corrosion caused by small molecule organic acid has been experienced in vacuum overhead and the corrosion rate of the 2nd fraction of vacuum distillation is relatively high. The problems of corrosion caused by small molecule organic acid, the corrosion of vacuum tower packings and corrosion of 2nd fraction of vacuum distillation are analyzed and countermeasures are recommended.