Fuel testing: VLFSOs – the black carbon in the Arctic debate

By way of a definition, black carbon is created during the combustion process of carbon-based fuels. Mr Javaid noted that the discussion around black carbon started from a paper submitted to IMO in regards to the impact on the Arctic. “How that paper was presented led to the perception that although the industry had taken a bold step in reducing sulphur in fuels, the low sulphur fuel oils were producing black carbon because they were more aromatic,” explained Mr Javaid.

Three elements are required to produce black carbon, aromaticity of the fuel, engine type and condition, and combustion performance. Mr Javaid noted that, at the time the paper was written, there were very few low sulphur fuels available. Second, the engine was a four-stroke, which are inherently less robust than two-strokes in dealing with black carbon. “But above all,” said Mr Javaid, “the combustion performance within the engine itself is critical and the main influencer in the production of black carbon.”

Mr Javaid presented combustion properties data based on over 10,000 samples of fuel oils taken since the implementation of IMO 2020 on 1 January 2020. The scattergraph shows the range from high aromatic to more paraffinic and shows the low sulphur fuel oil samples were not more aromatic than that of the high sulphur fuel oils.

“When you look at the very low sulphur fuel oils, all the data shows that approximately 30% of those fuels tested by FOBAS fall into the category of equally aromatic as high sulphur fuel oils, but none are more aromatic. In fact 70% (of low sulphur fuel oils) are less aromatic,” said Mr Javaid.

Taking into account other testing parameters, the only conclusion that can be drawn, noted Mr Javaid, is that VLSFOs are not more aromatic than HSFOs.

Ms Røjgaard picked up on Mr Javaid’s point about the engine type and combustion process. “We know that medium- and high-speed engines have a higher tendency of forming black carbon, they are more sensitive than the low-speed two-stroke engines,” said Ms Røjgaard.

She added, “We also know that the engine maintenance, the condition, and the operational profile together have an impact on the tendency to form black carbon.”

Returning to the 2018 black carbon Arctic paper, Ms Røjgaard noted the actual specifications of the fuels used is not known and it is difficult to compare to the

VLSFO in use today. “What we do know is the aromatic content (of the tested fuels) was higher than that of the heavy fuel oils of the time.”

Ms Røjgaard added that the tested fuels were sought and bought before the VLSFO formulation was known. In conclusion to her presentation, Ms Røjgaard said, “The focus on VLSFOs is factually incorrect, and we need to take that into consideration.”

“VLFSOs account for 66% of all fuel samples sent for testing by VPS,” said Mr Bee. One aspect worth noting was that it was expected there would be higher levels of cat fines in VLSFOs.

“In fact, they (cat fines levels) have been lower than expected so far,” said Mr Bee. “The key problematic areas related to VLSFOs has been their cold-flow properties and stability.” This is generally due to poor storage conditions of the fuel.

VSP analysis shows that: VLSFOs had a greater paraffinic (wax) content than HFO; the pour point (PP) of VLSFO is considerably higher than HFO; 5% of VLSFOs had a PP <30^oC; 66% of VLSFOs had a WAT >30^oC; average WAT being 20^oC greater than the average PP; 75% VLSFOs had a WDT 40^oC.

“We also witnessed VLSFO had a much shorter shelf life, of about three months, which means the stability of the fuel needs careful monitoring,” said Mr Bee.

Where does the industry stand on fuel use in the Arctic? In a poll, 83% replied they would burn distillate fuel (MGO) while operating in Arctic waters with 17% replying in the negative.

Given options on the best way to deal with black carbon emissions for the Arctic zones: the majority (46%) chose: mandatory use of distillate fuel (MGO); use VLSFOs as the cleaner alternative to traditional HSFO; install a scrubber; include aromaticity within ISO 8217; set emissions limit at exhaust level.

A further 25% chose: set emissions limits at exhaust level; mandatory use of distillate fuel (MGO); use VLSFOs as the cleaner alternative to traditional HSFO; install a scrubber; include aromaticity within ISO 8217.

Had the discussion and presentations cleared up the perceptions set in the 2018 VLSFO Arctic paper? The answer appears to be yes: to the poll question In your opinion which fuel type emits more black carbon emission? Only 9% choose VLFSO with most (88%) picking heavy fuel oil (with 3% going for MGO).

Putting the Arctic and VLSFO carbon emissions aside, the big long-term question is: Do you believe shipping can achieve the greenhouse gas and CO₂ emissions reduction targets by 2050? Strongly agree 8%, agree 50%, disagree 10%, strongly disagree 2%, too early to call 30%.

Only a relatively small percentage had no faith in the shipping industry’s ability to meet the target, but nearly a third thought it too early to call. It will be interesting to see the results of the same poll in 12 months’ time.

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From left to right: Bureau Veritas VeriFuel global head Charlotte Røjgaard; Lloyd’s Register EMEA FOBAS global operations manager, Naeem Muhammad Javaid; and Veritas Petroleum Services group commercial & business development director, Steve Bee.