The closing of the light/ heavy crude spreads and generally high crude prices have made production of very heavy crudes economically attractive. The next challenge refineries will face is converting heavy, sour, and high metal content feedstocks into high quality transportation fuels (e.g. Euro V). This paper will consider alternatives including traditional configurations to be considered by new refineries, low-cost alternatives for implementing higher conversion capacity in existing refineries, and some of the newer technologies which will likely be considered in refineries of the future.
For grassroots refineries, depending on the heavy crude slate to be processed and the specific market trends (maximum gasoline or maximum diesel production), there are several traditional configurations that allow flexibility. These include a fluid catalytic cracker (FCC) with a hydrocracker (HCU) and a delayed coker (DCU) or residue hydroprocessing unit (RHP). Existing refineries without heavy-end conversion configurations can consider evaluating the purchase of existing delayed coking capacity (or components from units never built) at low prices rather than investing in new thermal upgrading capacity.
Non-traditional new or ‘novel’ technologies may consider over-cracking at the FCC unit to produce larger quantities of light olefins that can be polymerized to produce a high quality diesel product. Another newer approach is gasifying heavy residue or upgrading petroleum coke to produce synthesis gas that can be converted into high quality diesel via Fischer-Tropsch technology. Producing "green diesel" via hydrotreating or trans-esterification vegetables oils will also make-up a portion of the future global diesel pool. Longer term, bioengineered microbes may be produced to selectively convert heavy hydrocarbons into diesel.
