To improve the economic efficiency of the enterprise, PetroChina Yunnan Petrochemical Company Limited purchased relatively inferior crude oil such as Saudi Arabia heavy crude, Basra medium crude for processing. As a result, the sulfur, chlorine and salt content and other properties of atmospheric residue, vacuum residue and mixed residue entering the fixed-bed residue hydrotreating unit had significantly worsened and deviated from the initial design condition, and the impurities such as sulfur and nitrogen in mixed residue were deeply hydrotreated, resulting in serious problems such as salt deposition, blockage, corrosion, and leakage at the stripper overhead air cooler, which directly affected the safety and smooth operation of the unit. Based on the analysis, the wall thickness of pipelines at the top of the stripping tower was increased, and special equipment for removing ammonium salt was added to the unit; the requirement of sulfur content for hydrotreated residue was appropriately relaxed to reduce the reaction depth of hydrotreating desulfurization and hydrotreating denitrification; in addition, the process of water injection and corrosion inhibitor injection was adjusted and optimized in time.

为提升企业经济效益，云南石化采购加工了沙重、巴士拉中等较为劣质的原油进行加工处理，进入固定床渣油加氢装置的常压渣油、减压渣油以及混合渣油原料硫、氯、盐含量等性质明显劣质化且偏离了装置初始设计工况。同时，硫、氮等杂原子又得到了深度加氢脱除转化，从而导致装置的汽提塔顶空冷器出现较为严重的结盐堵塞、腐蚀泄漏等问题，直接影响装置安全平稳运转。针对结盐腐蚀的问题及其原因，改造升级了汽提塔顶管道的壁厚，同时还增设了在线除盐设施，适当放宽了对加氢渣油硫含量的要求，降低加氢脱硫和加氢脱氮的反应深度，此外，还及时调整优化了注水和注缓蚀剂的过程。