Refinery Perspective on Decarbonizing with Marine Biofuels

This work seeks to understand what biofuel production pathways a refinery might prefer to produce very low sulfur fuel oil (VLSFO) for marine applications. A comprehensive refinery optimization model was modified to allow for (1) direct blending of soy biodiesel, renewable diesel, Fischer-Tropsch diesel, and several pyrolysis oils and (2) indirect blending of all pyrolysis oils via co-processing in a fluidized catalytic cracker (FCC) and diesel hydrotreater into the marine fuel pool. Results showed that preferred pathways to bio-VLSFO production included co-processing low-quality pyrolysis oil in a FCC to blend the resulting biogenic light cycle oil, directly blending soy biodiesel, and directly blending small quantities of pyrolysis oil. Bio-VLSFO production costs were compared to those of fossil VLSFO subject to different marine fuel demands, benchmark crude oil prices, and biogenic fractions in the finished product. Given benchmark crude oil prices over 60 $/bbl, bio-VLSFO production appeared to be significantly cheaper than fossil VLSFO. Corresponding marginal abatement costs of CO2 mostly ranging from -300 to 350 $/ton of CO2 were also determined using a simplified but novel approach to allow for a comparison to other decarbonization strategies. This work indicates that low-sulfur contents in biofuels, relatively relaxed specifications for marine fuels, and current difficulties in meeting VLSFO specifications with crude oils can combine to make bio-VLSFO production cost-effective. Moreover, marine fuels appear to be a good entry point for refiners to start decarbonizing with biofuel pathways that could eventually be extended to other product pools.