关键词: 渣油加氢装置, 冷高分, 油水乳化, 开工过程, 反应温度, 掺渣比

Abstract: Two series of a 4.0 MM TPY residue hydrotreating unit have experienced three times catalyst change since the first start-up. In December 2018, the second series replaced FRIPP catalysts. In December 2019, the first series replaced RIPP catalysts. In April 2020, FRIPP catalysts were used again in the second series. During the process of increasing the residuum blending amount after the first two times of catalyst change,when the reaction temperature was about 360 ℃ and the residue ratio of feedstock was more than 76%,Oil-water emulsification occurred in the cold high pressure separator, which brought great danger to the safety production of the unit. The reason of emulsification may be that macromolecular asphaltene would undergo side chain scission reaction when the hydrogenation reaction temperature and the reaction depth were not enough, forming smaller and more polar asphaltene, and the combination of smaller and more polar asphaltene with water to form a more stable emulsion. The average reaction temperature was raised to 370 ℃ before the residue ratio was raised to 76%, which can effectively avoid the occurrence of oil-water emulsification in the cold high pressure separator.

Key words: residue hydrotreating unit, cold high pressure separator, oil-water emulsification, start-up process, reaction temperature, residue ratio