Abstract:

The problems in existing process anticorrosion management and implementation of atmospheric and vacuum distillation are analyzed, the low-temperature corrosion mechanism and control countermeasures of three overheads(primary tower top, atmospheric tower top, vacuum tower top) of atmospheric and vacuum distillation unit are studied. Through process simulation, the influencing factors and control strategies of low-temperature corrosion on the atmospheric tower top of the typical device under different working conditions are studied, and the process anticorrosion precise injection target database is established. Through the development of highly reliable on-line pH meter, intelligent control system, injection skid mounted equipment and integrated management and control software, the process anticorrosion intelligent injection system of atmospheric and vacuum distillation unit overhead system has been successfully developed. By applying this system into operation for one and a half years, it has operated stably and reliably. The iron ion concentration in the reflux tank on the top of the tower has decreased by 55.8%, indicating that the risk of low-temperature corrosion on the top of the tower has decreased, the reagent consumption has decreased by more than 1/3, the pH value of condensate in the reflux tank has been controlled more accurately, and the mass concentration of oil in the water has been reduced by 23%, effectively realizing the intelligent control of process anticorrosion.

Key words: atmospheric and vacuum distillation unit, tower top process anticorrosion, control countermeasures, intelligent injection system, iron ion concentration, dew point, injection quantity, pH value

摘要：

分析了常减压装置现有工艺防腐蚀管理与实施存在的问题，研究了常减压三顶(初馏塔顶、常压塔顶、减压塔顶)低温腐蚀机理及控制对策，通过工艺仿真研究了典型装置常压塔顶不同工况下低温腐蚀的影响因素及控制策略，并建立了工艺防腐精准加注目标数据库。通过开发可靠性高的在线pH仪、智能控制系统、注入撬装设备和管控一体化软件，成功研制了常减压装置塔顶工艺防腐智能加注系统。该系统自正式投用一年半以来，运行稳定可靠，塔顶回流罐铁离子浓度下降55.8%,表明塔顶低温腐蚀风险下降，药剂消耗量降低1/3以上，回流罐冷凝水pH值控制更精准、水中油质量浓度降低23%,有效实现了工艺防腐的智能控制。

关键词: 常减压装置, 塔顶工艺防腐, 控制对策, 智能加注系统, 铁离子浓度, 露点温度, 加注量, pH值