Abstract: Since the 2.0 Mt/a heavy oil FCC unit in Yan'an Refinery was put into operation, the blockage and corrosion leakage of trays in the fractionator, air cooling exchanger, pump, oil and gas pipeline, heat exchanger and other problems occurred for many times, which seriously affected the safe operation of the unit. Some common measures for corrosion inhibition, such as adding corrosion inhibitor, online water washing, increasing washing water quantity had been adopted to solve the problem of salt corrosion, which had contributed to stable operation of the unit. In 2020, the combined method of turbulent mixing, downstream extraction and deep separation of oil and water was adopted to carry out on-line desalting technical transformation for the circulating reflux system at the top of fractionator. The corrosive medium and soluble salt in top circulation oil were extracted by water injection. The mass fraction of chlorine ion in the oil from the top circulation system could be decreased to less than 2 μg/g and the removal rate of chlorine ion was reached 80%. The desalting effect was obvious.

Key words: catalytic fractionators, online water washing desalination, turbulent mixing, top circulation, deep separation of oil and water

摘要： 延安炼油厂2.0 Mt/a重油催化裂化装置自投产以来,先后多次出现分馏塔塔盘、空气冷却器、机泵、油气管线、换热器等堵塞和腐蚀泄漏问题,严重影响装置安全运行。为解决结盐腐蚀问题,采用了加缓蚀剂、在线水洗、加大水洗水用量等常规处理措施,取得了一定的效果。2020年对分馏塔塔顶循环回流系统实施了在线除盐技术改造,采用湍旋混合-顺流萃取-油水深度分离的组合方法,注水萃取分馏塔塔顶循环油中的腐蚀性介质和可溶性盐类,投用后分馏塔塔顶循环油氯离子质量分数稳定在2 μg/g以下,分馏塔塔顶循环系统氯离子分离脱除率达到了80%左右,除盐效果明显。

关键词: 催化分馏塔, 在线水洗除盐, 湍旋混合, 分馏塔塔顶循环, 油水深度分离