Tue 16 Jan 2024, 16:22 GMT | Updated: Tue 16 Jan 2024, 16:23 GMT

ISO 8217 formula 'not suitable' for gauging FAME fuel energy content: VPS


Accurate measurement can only be determined using calorimetry, says testing firm.


Algebra illustration.
VPS says the ISO 8217 equation is able to calculate the energy content of conventional fuels and distillates to a good degree of accuracy because of the empirical linear relationship between density and energy content; but this relationship does not hold when the fuel contains oxygenated compounds, such as FAME in biodiesel. Image credit: Pixabay

VPS has published a white paper where it asserts that the existing ISO 8217 formula for calculating energy content — a key test parameter — is not accurate for fuels containing FAME, such as biodiesel.[1]

Energy content represents the amount of heat transferred within the combustion chamber during the burn process and indicates the available energy from the fuel. Higher energy content results in higher power generation and better combustion efficiency. The energy content has a direct impact on fuel economy and greenhouse gas emissions and is therefore an important parameter for ship operators to consider in preparation for the EU ETS.

In the VPS research paper, a number of conventional fossil fuels and biofuels with varying FAME content were measured using the ASTM D240 method and the energy content compared with that obtained using the ISO 8217 calculation method (which uses a formula specified in Appendix H of the International Marine Fuel Standard ISO 8217:2017).

The results show good correlation for conventional fuels and distillates, indicating that the ISO 8217 calculation method provides an acceptable degree of accuracy for measuring energy content in conventional fuel types. However, according to VPS, this correlation falls away at FAME content above 10%, thus demonstrating that the ISO 8217 calculation method cannot be relied upon to provide accurate energy content for fuel blends containing more than 10% FAME and that, for these blends, the accuracy of the calculation formula is not acceptable, and accurate energy content can only be determined by measurement using calorimetry.

"This inaccuracy," VPS says, "is due to the greater oxygen content of FAME ... as compared to conventional fuels (which typically contain very little oxygen)."

The ISO 8217 formula is only based on the linear relationship between density and energy content, VPS explains, but does not account for oxygen present in FAME.

As the FAME and the oxygen in the FAME are both variables, a linear relationship between the FAME and the energy content could therefore not be established in studies carried out on biofuels with varying FAME content.

For blends containing more than 10% FAME, VPS concludes that the accurate assessment of energy content requires direct measurement (rather than an equation calculation) using the ASTM D240 method, which uses an oxygen bomb calorimeter to determine the energy content.


Notes

[1] Sign up to a subscription plan to view notes and source information.


Venture Energy, CSST and CSTC MoU signing. Venture Energy signs green methanol cooperation agreement  

MoU establishes framework for long-term offtake and capacity development in maritime decarbonisation.

Iberdrola España Onshore Power Supply (OPS). Iberdrola España completes shore power installation at the Port of Pasaia  

Spanish utility installs an onshore power supply system, enabling docked vessels to use renewable electricity.

Illustratic image of Itochu's newbuild ammonia bunkering vessel, scheduled for delivery in September 2027. Itochu secures approval for ammonia bunkering trials in Singapore  

Japanese trading house to conduct two-year trial following MPA authorisation.

Oceanic Moon alongside Gas Utopia vessel. Safe ammonia bunkering in ports is possible, according to MAGPIE project findings  

EU-funded MAGPIE project validates safety frameworks for ammonia bunkering operations in commercial ports.

RS Onza vessel. Suardiaz Group acquires methanol-capable tanker RS Onza for Moeve operations  

IMO2 chemical tanker to operate in European ports, primarily Spain, for energy company.

Steel-cutting ceremony for vessel with builder's hull no. S1157. Construction begins on 20,000-cbm LNG bunkering vessel for GSX Energy  

Chinese shipbuilder starts work on upgraded dual-fuel vessel with enhanced economy and energy efficiency features.

Tiger Fisher vessel alongside Narwhal Fisher vessel. James Fisher dual-fuel tankers named at Chinese yard  

FKAB-designed newbuilds are part of four-vessel FKAB T68 series and include LNG and LBG capability.

Factory Acceptance Testing (FAT) for X52DF-A-1.0 engine. WinGD completes factory testing of ammonia-fuelled engine for LPG carrier  

X52DF-A-1.0 engine tested in China ahead of installation on first of four vessels under construction.

Drift Energy energy-harvesting ship render. RINA awards first approval in principle for energy-harvesting ship  

Drift Energy receives certification for vessel design that generates clean energy at sea.

MSC World Europa vessel. MSC Cruises achieves flag state recognition for verified methane emissions data  

Bureau Veritas certifies actual methane slip values for two LNG-fuelled cruise ships.