Q & A > Question Details
Is designing wash section critical in vacuum column if my objective is to get only asphalt from vac column bottoms? VGO we will be selling as fuel oil.
Now it is a dry vacuum column. Is it possible to convert this into a wet vac column?
I am able to match the Flash zone temperature with HTSD data for RCO without assuming entrainment as mentioned by Golden in Deep Cut Vacuum feed characterization article. So can I assume the actual entrainment would be zero?
03/10/2007 A: Amarjit Bakshi, Refining Hydrocarbon Technologies LLC, abakshi@rhtgulfcoast.com
As per your present plan, VGO is going to be sold as Fuel oil so specifications is not a problem as per other response, which is correct. But I think I would recommend that the wash section is designed with care, so as to remove most of the heavy metals so when and if the VGO is fed to FCC or Hydocracker in future, you don't have to make any changes i.e the design should consider the refinery economics for the future. Just a caution for future plans, if any.......
06/09/2007 A: Scott W Golden, Process Consulting Services Inc, SGolden@revamps.com
It is very unusual to sell VGO as fuel oil. Because nearly all VGO is fed to an FCC or hydrocracker, its MCR and metals should be minimized while meeting the asphalt specifications. If VGO is sold as fuel oil there are no quality constraints on it. Ultimately wash section performance is irrelevant when VGO is fuel oil.
Vacuum flash zone entrainment is never zero. Moreover, entrainment does not influence the asphalt distillation as most (99.9% or more) is generally removed by the wash section packing and returns to the bottom of the column. ......