Oil Trade House Technical Interview

Prepping for an upcoming interview and came across a past question: “explain the major units of a refinery, how different slates have different characteristics, how these characteristics are affected by the units they run through, and what products would come out of these units.”

My answer would generally focus on describing the distillate tower, catalytic cracking (FCC / hydro cracker), reformer, hydrotreater, and coker. Then I’m confused what they mean for the difference characteristics of slates part but perhaps focusing on how different refineries are optimized to run heavier, sour blends vs sweeter blends in the US due to a historical anticipation of having to refine Russian crude. In terms of how this would impact the units, depending on whether the slate is heavier or sour, this would have an impact on the products that certain units are optimized to produce. For example, a Coker is better for heavier crudes and would yield heavier products like petroleum coke. An FCC would run better on lighter gas oil to yield gasoline vs a hydro cracker provides a wider range of products preferring heavier crudes yielding diesel, jet fuel, and gas oils. Hydrotreaters are especially suited to non-polluting jet fuel while reformers for gasoline (especially from naphtha so lighter crudes would presumably be better here). 

I would appreciate any feedback to refine my answer or insight if I am in the right direction.