Step-Out Improvements in Heavy Oil Conversion

Present heavy oil conversion processes, either coking or hydroconversion, are far from achieving their maximum conversion1. With the remaining petroleum resources, on average, having a greater fraction of the vacuum resid fraction, it is imperative that new resid conversion processes or schemes be developed to approach their full potential. Coking processes are limited because they degrade the higher quality fractions of the vacuum resid and because they crack volatile liquid products to form hydrocarbon gases. By overcoming these limitations, the laboratory coking of Arabian Heavy vacuum resid increased the yield of nearly equal quality liquid product to 76 wt%, compared with a commercial yield of 61 wt%, while reducing the coke yield to less than Conradson carbon residue.

Ebullating bed hydroconversion processes, H-Oil and LC-Fining, are limited by the formation of asphaltene sediments in the heavy oil product and/or coking in the reactor or separator. Several methods of overcoming these limitations will be presented. Once slurry catalyst hydroconversion processes are designed to overcome their compatibility limitation by more efficiently stripping out the volatile liquid product, they can produce greater than 100 vol% liquid product. However, the economic optimum conversion is more likely at lower conversion but it greatly depends on the local economics. Reference Cited

1. Wiehe, I.A., “Process Chemistry of Petroleum Macromolecules”, CRC Press, Boca Raton, FL, 2008.