Maximizing Conversion of Residues to Chemicals and Clean Fuels

Abstract

International Maritime Organization’s Marine Fuel Rule, or IMO 2020, is just around the corner. Few refineries are ready for the change to bunker fuel specifications caused by IMO 2020 where marine bunker fuel sulfur content will be reduced to 0.5 wt% from current 3.5 wt%. Many refineries around the world, who currently produce about 4 million barrels per day of high sulfur bunker fuel stocks, still need to invest in upgrading technologies. In the past Visbreaking was used to make Residue Fuel Oil (RFO) as it reduces the viscosity of the resid by thermally cracking the heavy molecules, thereby minimzing cutter stocks. It also has a relatively low capital and operating costs compared to other residue upgrading technologies. However, it concentrates contaminants (sulfur, nitrogen, and Conradson Carbon Residue (CCR)) in the product. As a result, it is not considered a viable solution for RFO sulfur reduction. Fortunately, there are several technologies available to upgrade the high sulfur residuum oil to high value products or low sulfur fuel oil as shown in Figure 1. The benefits and features of each of these options is discussed in this paper to provide an understanding of the various processes’ merits. Case studies are also provided to provide indications of which technologies are best suited depending on the specific scenario.