With the recent downturn oil prices, the incentive to upgrade residues has also shifted as upgrading mar- gins have been compressed. To maximize upgrading margins, technology solutions that maximize high quality, high hydro- gen content transportation fuels (gasoline, kerosene, and diesel) and minimize uncovered residues are required.
 
Several technologies are available for residue upgrading, broadly characterized as car- bon rejection technologies or hydrogen addition technologies. The principal residue conversion based on carbon rejection technology is delayed coking. Delayed coking is simple, robust, and can handle very high levels of feed contaminants. Roughly 25-30% of the residue is rejected as petroleum coke, or petcoke. Amongst hydrogen addition technologies, the principal ones are residue desulphurisation technologies (ARDS, VRDS, UFR, and OCR) and residue hydrocracking technologies such as LC-FINING. These technologies are all established and have proven to  be  efficient  and  reliable  processes. Each technology has its own merits.