Re.: Vacuum Distillation

[Deremis]

How can I increase the viscosity of the bottoms of a Vacuum distillation unit if I'm limited by the inlet temperature to the column. I'm not sure what else could affect the vicosity.

Thank you.

 

[25362]

I assume you are speaking of a crude unit vacuum tower. Your question would be equivalent to increasing the yield of VGO. Ideas that come to mind:

1. Improve your vacuum at the flash zone. For example, by changing tower internals over to structured packing to reduce pressure drops.

2. Improve the coke washing bed and the wash oil spread header.

3. Draw off your liquid overflash before it falls back to the bottom section. Use a chimney tray.

4. Increasing stripping steam, if allowed.

5. Install a solvent extraction step, such as a PDA unit.

The list isn't exhaustive. Good luck.