FCC and HXX Feed Characterization Issue with Viscosity - Supplementary Information

This page provides details on how you can assess the likely impact of the viscosity transfer issue on existing cases without having to rerun those cases.

FCC

You can do your own cross-check on the likely impact of this issue by inspecting existing refinery-wide cases and looking at the FCC feed characterization:

  1. Look first at the Feed CA Characterization Method on the Operating Data \ Feed Data page of the reactor: if anything other than Default your results will not be affected
  2. Look next at the Feed Data matrix From Feed column for each feed: if the Viscosity property shows 0.0, your results will not be affected for that feed
  3. For affected feeds, open the stream view of that feed and find its Kinematic Viscosity at 50 C and 100 C in cst from the stream properties page
  4. Calculate the core aromatics (CA) delta from deltaCA = (V50-V100)*0.080081. This will be the percentage point reduction in CA that you would see if the issue were not present
  5. It is the impact on total feed CA that is important and you can calculate this from the mass-weighted sum of the individual feed deltaCA terms. The deltaCA for any feed where the Viscosity property seen in step 2 is 0.0 will be zero.
  6. You should inspect results carefully where the delta CA is greater than 0.5%

HXX

The impact on hydroprocessing is more subtle and you can calculate the delta on core aromatics as follows:

  1. Look first at the Feed CA Characterization Method on the Operating Data \ Feed Data page of the reactor: if anything other than Default your results will *not* be affected
  2. Look next at the Feed Data matrix From Feed column for each feed: if the Viscosity property shows 0.0, your results will *not* be affected for that feed
  3. For affected feeds, open the stream view of that feed and find its Kinematic Viscosity at 100 C in cst from the stream properties page
  4. Calculate the core aromatics (CA) delta from deltaCA = (V100-50.0)*0.080081. This will be the percentage point change in CA that you would see if the issue were not present – if V100 is greater than 50 cst you will see an increase in feed core aromatics, otherwise you will see a reduction.
  5. It is the impact on total feed CA that is important and you can calculate this from the mass-weighted sum of the individual feed deltaCA terms. The deltaCA for any feed where the Viscosity property seen in step 2 is 0.0 will be zero.