Item 2 about not running cokers when margins are slim between swt – sour crudes might be tad simplistic.
Even when the differentials are small it is still a postive differential and hence higher earnings which might be critical to reducing
loss on Refinery. ALso remember that small differences on crude margins become larger coker margins.
This is more so when the refinery has just had a capital outlay for expanded or new coking unit added or even when there is just drum replacement. A capital cost added to the operating cost values for the refinery/coking unit – the gross margin these days between swt-sour to justify coker during the 2006-2011 cycle is ~$10/Bbl (compared to $5/bbl on previous 1999-2005 cycle).
I would like add item call it #3 – have refineries actually captured the FCC/Coker shadow price on gasoils due to the higher portion of the LS Fuels Desulfurizing cost from these units (ie 75% Gasoline & Diesel pool’s sulfur is from FCC+Coker units intermediate streams). Also it has become clear that few oil companies actually achieve much more than the cost of LS Fuels and the expected premium never showed up (was masked for while by the Speculated crude & products price spikes).
