降低常减压装置重蜡油残炭的可行性探讨

针对常减压装置重蜡油(减四线)残炭、Ni,V等含量居高不下、难以作催化原料的问题,确认常压塔塔内雾沫夹带严重,使柴油拔出能力降低、操作稳定性变差,是造成减压拔出率降低的主要原因;优化常压塔拔出率、实现减压深拔是解决问题的关键。根据模拟计算,可将常压重油中低于350℃馏分油质量分数操作值由目前的12.5%降低到6%,减一线馏分的柴油量可比原操作值降低90%。调整常压拔出率,使减压塔分离效果大幅改善,雾沫夹带和减顶缩径段压力降降低,减四线残炭及金属含量可大幅度减少。

Feasibility study on reducing carbon residual of heavy gas oil in atmospheric and vacuum distillation unit

The causes of high carbon residue,Ni,V,etc in the heavy gas oil (4th vacuum side-draw) of the atmospheric and vacuum distillation unit which can not be used as the feedstock of FCCU are analyzed.The culprits are that the lower draw-out rate of diesel,poor operation stability,lower draw-out of vacuum unit and internal foam carry-over of the distillation tower.Therefore,it is very critical to optimize the draw-out rates of atmospheric and vacuum distillation towers and realize the deep vacuum draw-out.Based upon the simulation calculations,the fraction of ≯ 350 ℃ in atmospheric residue can be reduced from 12.5％ to 6％,and the diesel of 1 st vacuum side-draw can be lowered by 90％.The draw-out in atmospheric tower has greatly improved the separation efficiency of the vacuum tower,reduced the foam carry-over,lowered the pressure drop in reducing section of vacuum tower overhead and reduced the carbon residue and metal in the 4th vacuum sided-raw.