Steam Flow To A Lube Oil Vacuum Tower???

[Schleder07]

Hey guys,

I am trying to troubleshoot a lube oil vacuum tower at the Refinery I work at. According to the literature that I have been reading - the steam flow to the side strippers should be approximately 0.2 lb of steam per gallon of product or 8.4 lb/bbl.

Does the same hold true for the main tower?

Right now the steam flow is 2,000 lb/hr and is in flow control. The steam flow to the side strippers are in ratio control with the bottoms product.

The reason why this is important is that the overhead pressure is erratic and I starting to climb....especially with summer conditions approaching. Right now the overhead pressure is reading ~68.5 mmHg and I want to get this down to 60 mmHg without compromising product quality.

I am currently working on a project to replace the Pre-Condenser for the next major shutdown. But right now I am just trying to make what we have work.

Any advice?

 

[25362]

Once upon a time I read that by rising somewhat the flash zone temperatures the vacuum improves -counterintuitively- because the added condensed hydrocarbons in the pre-condenser act as absorbers of the lights, reducing the load to the vacuum system.