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

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