Q & A > Question Details
I have a question on determining if the atmospheric residue is lighter from the atmospheric distillation unit. I know I can compare the T5 distillation of my residue to see this has been lower than historical values... I think if I were to check the delta across my stripping section has increased with a constant stripping stream ratio, that'll probably give some indication too.
Does anyone know what other methods can be used to check if I am actually dropping any HGO or light molecules down to the atmospheric resid layer?

Yes, I have compared the T5 of my residue and also the T5 of the vacuum tower feed and they are lighter. My stripping steam, FZT were lower than usual during those period while my FZP was higher. I think in conclusion, those should have actually caused the drop of lighter molecules to bottoms due to insufficient uplift of molecules.
29/03/2018 A: Rajkumar Chate, Sulzer, rajkumar.chate@sulzer.com
You can compare the temperature difference across the stripping section, higher delta temperature at same stripping steam means you strip out more light components, however this does not tells us the amount of GO we loose with residue. Better way is to compare T5 % and then you can check how much GO you loose. Another way is to compare flash point, if it is higher then less GO is goint with residue and vice versa. Flash point is just to compare the two results but if you really want to know how much GO you are loosing with residue then only way is distillation method/curve.
28/03/2018 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Are you at the maximum furnace outlet temperature without the crude cracking? Are you at 3-5% overflash? Do you have the optimum amount of bottom stripping steam? Is the overhead receiver pressure slightly above atmospheric? If all answers are "yes", you are minimizing bottom product rate with your equipment.
You can simulate the operation and perform a case study wherein the bottom stripping steam is varied. Using the value of your steam, the optimum amount of steam can be determined.