3 replies to this topic

[tashaqsc]

Hi All

Hoping you guys can offer some insite on this.

We recently adopted the approach of optimizing our lubes vacuum unit to achieve maximum distillate yields. The testrun was to increase stripping steam to max, and then turn up the COTon the feed furnace.
With these changes the distillate yields did increase as anticipated, with rundown specs not being violated in terms of viscosity and RI. However what was observed on the Lubes plant was a drop in yields when processing the feed, and was attributed to higher wax content on the feed.

Is it therefore possible, that increased stripping and "cracking" on the unit can force a higher wax content on the lubes distillates without it being picked up on a viscoisty check / RI? Distillation cutpoints and draw temperatures were not significantly different from previous

[Himanshu Sharma]

Can you please tell me that whether you have a catalytic dewaxing unit or Solvent Dewaxing unit in your lube plant.

I presume that Distillate is been referred to vacuum Diesel and feed to the lube unit is HVGO or MVGO or combined,please confirm.

Edited by Himanshu Sharma, 06 March 2012 - 12:31 PM.

[tashaqsc]

Hi

The distillates I am referring to is of the Vacuum unit, which processes Crude(atmospheric) tower residue. The distallites that we rundown to our lubes based plant are 100 Neutral, 150N, 330N and 600N. (TBP 350 - 600degC).
The heavier grades(600N) seemed to yield the higher wax content.

The lubes plant uses a solvent based dewaxing unit which saw their yeids drop by 30 - 40%.

[Himanshu Sharma]

Can you please tell me where you have this refinery/plant located !

Solvent Dewaxing is the one of the Technologies we recently developed and licensing in asia region.

Its a technology where well defined co relations for unit performance predictions are not available and every feed stock has to be run in the pilot plants for crystallization temperature and batch filtration.Then the dilution injections and temperatures are defined and modelled.

In a nut shell ,feed change hits SDU worst than other unit and has to be handled carefully if there's a vast variation in feed endpoint.