腐蚀在线监测系统在常减压蒸馏装置上的应用

装置主要加工高硫高酸原油,酸值一般在1.685 mgKOH/g左右,硫的质量分数在1.97%左右。通过腐蚀在线监测发现,常顶空冷EA101E腐蚀速率由0.07 mm/a快速增加至0.17mm/a,升高近2.43倍,其原因是由于中和剂效果较差,致使介质的pH值偏低所致;减顶冷却器E144A腐蚀速率由0.085 mm/a上升到1.000 mm/a,增加近11.76倍,导致腐蚀加剧的原因是切换减顶两组冷却器时停注防腐剂所致;装置检修期间E144A腐蚀速率由0.141 mm/a上升到0.889mm/a,增加近6.30倍。投用腐蚀在线监测系统不仅能及时跟踪装置腐蚀变化趋势,还可以指导工艺调整防腐蚀措施,避免腐蚀事故的发生。提出了腐蚀在线监测系统今后应在安装结构形式、干扰数据分析及排除等方面的改进措施。

Application of on-line corrosion monitoring system

The No. 4 crude unit is mainly operated to process high - sulfur and high TAN crude with an acidic value of 1. 685 mgKOH/g and sulfur of about 1.97 m%. The on - line corrosion monitoring has found that the corrosion rate of overhead air cooler EA101E of atmospheric tower was increased to 0.17 mm/a from 0.07 mm/a, which was an increase of 2.43 times. The cause was the poor performance of neutralizer, which led to the lower pH value of media. The corrosion rate of overhead air cooler E144A of vacuum tower was increased from 0. 085 mm/a to 1. 000 mm/a, an increase of nearly 11.76 times. The culprits of intensified corrosion were the switch - over of equipment in operation and stop of injection of corrosion inhibitors. In the overhaul maintenance, the corrosion of air cooler E144A was accelerated to 0. 889 mm/a from 0. 141 mm/a, an increase of about 6.30 times. The application of on - line corrosion monitoring system can not only trace the corrosion changes of the unit in a timely manner but also provide a good reference for taking effective corrosion protection measures so as to avoid the occurrence of corrosion - related accidents. The improvements in installation of on - line corrosion monitoring system, interference data analysis and interference minimization, etc are recommended.