(154c) Recovery and Stripping issues at turndown conditions

During the refinery cutbacks in the first part of 2020, A FCC unit experienced LPG recovery and H2S stripping issues. The H2S in the naphtha was extremely high and could not be influenced by adjustments in the Stripper/Absorber or Debutanizer. The issue was isolated to one unit during a time when all the FCC’s were turning down due to reduced demand.

The troubleshooting was extensive and involved analytical, equipment rating and feed quality evaluations. The process manipulations were extensive and provided little benefit. The final solution turned out to be very simple and unexpected.