By Ara Barsamian, Eliseo Curcio, and Daniel Son, Refinery Automation Institute, LLC
Now that 2020 is here, one of the serious issues is one of safety of the VLSFO fuel; the other one is price.
- The safety issue comes from lack of standardization of VLSFO fuel composition and characteristics which directly affects engine performance and could potentially result in loss of propulsion and/or engine damage.
- Price of VLSFO depends on the price of blend components and profit margins. Low viscosity VLSFO implies greater proportion of more expensive gasoil whereas high viscosity VLSFO implies the use of much cheaper residues and FCC cycle oils and slurry. But what happened? High viscosity VLSFO is cheaper to produce but it can be used as-is like the “old” HSFO without any changes by shipowners in terms of engine performance, use of existing lube oil, or re-training personnel. This is valuable to shipowners (where 60% of the operating cost is fuel cost), and therefore commands a premium.
Because of the proliferation of so-called 2020-compliant “specs” and the resulting chaos in the marketplace, we are taking the initiative to propose 3 VLSFO specs based on current market VLSFO availability in approximately 3 viscosity clusters.
The proposed 3 VLSFO specs span the 30 to 380 cSt viscosity range, and are compliant with the existing ISO8217-2017 specs with some additions based on the “usability and fitness for use considerations” for VLSO fuels.
The proposed specs based on current VLSFO viscosity clusters are RMV30, RMV130 and RMV380 which parallel the existing RMB 30, more or less RMD80, and RMG380 except for Sulfur, and 3 additional tests: ASTM Spot Test, Shell P-value, and SARA (aromaticity and asphaltene contents).
- The ASTM “Spot” test, D7470 is an approximate indication of compatibility and stability
- The Shell P-value is a measurement of asphaltene solubility and precipitation due to compatibility/stability issues using Aromatics titration testing
- SARA measures Saturates, Aromatics, Resins, and Asphaltenes. SARA indicates the asphaltene solvent power of a fuel and susceptibility to paraffins catalyzing the asphaltene precipitation.
- o Aromaticity is critical to keep asphaltenes in solution, generally a level of at least 50% is needed.
- The Sulfur spec is pegged to 0.47 mass% to account for Marpol testing margins rather than ISO 4259 methodology of 0.59 of Reproducibility. This insures 95% confidence level of always meeting the IMO 2020 spec.
By ISO adopting the proposed VLSFO specs, it will promote stability of VLSFO pricing and performance, ensuring predictability for both shipowners and suppliers. We plan to send the proposed VLSFO specs to ISO Technical Working Group responsible for ISO 8217-2017 and PAS.
For additional information and comments, please contact the authors or attend our 2020 VLSFO bunker blending class in Houston, March 12-13, 2020.