Singapore — Global fuel testing and inspection company Veritas Petroleum Services has seen bunker fuel alerts rise sharply this year, with stability and cold-flow issues coming to the fore due to the increased use of very low sulfur fuel oils, VPS group commercial & business development director Steve Bee said in an interview with S&P Global Platts.
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The implementation of the International Maritime Organization's global low sulfur mandate on Jan. 1 accelerated the use of cleaner bunker fuels, with VLSFOs becoming the chief marine fuel choice to meet compliance.
"A lot of stability and cold-flow issues with VLSFOs, plus flash point issues with MGO and VLSFO, have been noted," Bee said Oct. 3. ahead of the 21st Singapore International Bunkering Conference and Exhibition, or SIBCON.
VPS has issued 37 bunker alerts to date in 2020 compared with only 18 over the same period of 2019, Bee said. Of the total, 17 or 46% were issued for flash point issues -- nine for MGO, five for VLSFO and three for HSFO, he said, adding VLSFOs account for 65% of all fuel samples tested by VPS.
The COVID-19 pandemic, which has triggered a drastic drop in crude oil and oil product prices, has added to the complexity.
"We believe the reduced demand for road and aviation fuels due to the COVID-19 pandemic has resulted in a surplus of these more volatile fuels and as a consequence they have been used as blend components within marine fuels, resulting in lowering the flash points of MGO, VLSFO and HSFOs," Bee said.
SHORT SHELF LIFE
A combination of sediment and cold-flow properties are among the biggest bunker fuel quality concerns for VLSFOs, Bee said, adding that VPS has also issued five sediment-related bunker alerts relating to VLSFOs to date in 2020.
VLSFO fuels are vulnerable to sediment issues due to the fuels being more complex blends of residual and paraffinic components, Bee said.
A combination of cold-flow and stability issues have resulted in VLSFOs requiring much closer fuel management monitoring, as they can become unstable very quickly, he said.
The average "shelf-life" of a VLSFO is less than three months, compared with six months for HSFO and up to 12 months for MGO, Bee said.
"We've seen a number of VLSFOs be delivered on-spec, yet within weeks they have become unstable. Storage and transfer temperatures are key with VLSFOs...therefore their pour points, wax appearance temperatures and wax disappearance temperatures are key parameters to measure, along with TSP [total sediment potential]," he added.
"There are now so many different fuel types available to ship owners and operators, especially with VLSFOs, in many cases the only common parameter is the fact they comply to 0.5% sulfur legislation -- after that the blends vary enormously," Bee said.
"With regard to off-specification of sulfur within VLSFOs this year, we saw a month-on-month decrease in samples where sulfur exceeded 0.5% from December 2019 -- 6% -- to April 2020 -- 1.1% -- but then from May, sulfur levels exceeding 0.5% began to increase again to 3.7% in August," he said.
"Of the 3.7% of samples having sulfur levels in excess of 0.5%, we found 0.8% exceed the 0.53% sulfur confidence limit," he added.
To avoid bunker fuel quality issues in general, Bee said shipowners and operators should try to know as much about the fuels they are purchasing and using, prior to burning the fuel.
They should monitor the fuel closely in terms of storage and transfer, which will involve advising, instructing and training the crew with regard to handling these new fuels onboard.
In addition, they should work closely with an experienced fuel management partner, Bee added.