Maintaining fuel quality is emerging as a concern following the sudden rise in tankers being booked for storage
The remarkable conditions created in the first months on 2020 will go down in tanker market folklore. The start of 2020 was a worrying time for tanker operators – had all the provisions and planning been enough to cope with the introduction of the IMO 2020 global cap on sulphur in marine fuel? Five months into 2020 and with the benefit of hindsight, it appears IMO 2020 went relatively smoothly; there was no loss of power on hundreds of vessels during the fuel transition and for the most part, there was no shortage of low-sulphur fuel oil or blended fuel either. The outlook for Q1 2020 was rosy, but not spectacular.
Then the Covid-19 pandemic swept away oil demand just as Saudi Arabia decided to punish Russia for not agreeing to production cuts by opening its taps. This now seemingly bizarre response of adding crude oil into a diminishing market caused the price of crude to collapse. The resulting price contango made the economics of buying and storing crude for future sale very attractive and traders rushed to book tankers for storage.
From an operational point of view, this sudden change from continuous service to static storage raises concerns over the fuel onboard the vessel. Bunkers are a huge investment, which need careful nurturing to maintain in peak condition, not only to maintain value, but to avoid damaging components and the engine downstream from the bunker tanks.
Marine fuel additive developer, manufacturer, and distributor Aderco’s managing director Rebecca Farrall summarised some of the actions that need to be taken before, during and after a tanker is on storage duty to maintain the quality and value of the fuel.
Ms Farrall recommended tanker operators ensure that their tanks are clean before loading the fuel to be stored. “This will reduce the risk of compatibility issues and, at the same time, reduce the risk of microbiological attack in the fuel,” she said.
“Tanker operators should consider carrying out additional fuel screening, such as GC-MS analysis, to check for chemical contamination and wax appearance temperature (WAT) and wax disappearance temperature (WDT) tests. These allow operators to manage storage and purification and minimise the risk of undesirable waxing/sludging problems,” said Ms Farrall.
With regards to very low sulphur fuel oil (VLSFO), in preparation for storage, the fuel should be treated with a surfactant-based fuel conditioner (such as Aderco 2055G), which will reduce fuel oxidation. Ms Farrall said: “Over time, fuels degrade and become more unstable; by using a surfactant fuel condition you can stop and/or reduce the rate at which the fuel becomes unstable, therefore preserving it for a longer period.”
The location of the tanker while it on storage duty can also affect the fuel in the bunker tanks. “If a vessel is in lay-up in a warm and humid climate, it is highly likely that condensation will occur in the bunker tanks. This fundamentally increases the risk of fuel oxidation and water contamination from micro-bacterial growth,” said Ms Farrall.
The latest reports from Fuel Oil Laboratories on VLSFO stability suggest there has been a rise in the average total sediment potential (TSP). Ms Farrall noted: “There have also been more fuels with off-spec TSP than before. TSP is a key indicator of stability and with there being an average increase and more off-spec fuels, it clearly indicates that there are stability issues out there. Whilst it would be unfair to say that all VLSFO fuels are unstable, it is also not fair to suggest they are all stable!”
“Condensation in the bunker tanks increases the risk of fuel oxidation and water contamination”
“We can also see a wider variety of viscosity fuels on the market,” she added. “Those lower viscosity blends (below 60CST) with a more paraffinic base are more sensitive to instability and this compounds the notion that there are stability issues within the market, even with in-spec fuels.”
Aderco also recommends that the treated fuel be checked during floating storage duties. Ms Farrall said: “Provided that the fuel has been treated with a surfactant fuel conditioner upon bunkering, we would recommend our clients check on their fuel every three months. “
There are many fuel additives on the market, and Ms Farrall recommended that when comparing products, operators look at two particular areas. The first is flash point: “Check the flash point – a product that claims to bring benefits from tank through to combustion must have a high flash point. If a product has a low flash point, then how can it chemically help at combustion? It will have burnt off long before you reach that point.”
The second item to compare is the dosage ratio/price per litre. Ms Farrall said: “Each additive has its own dosage rate and many shipping companies make a decision based on price per litre. But if each additive has a different dosage ratio, then it’s not a fair comparison. It’s really important to compare the ‘price per treated tonne of fuel’ rather than the ‘price per litre’ when making your comparison.”
Oil majors release IMO 2020 and LNG-ready lubricants
The 2020 sulphur cap is now in place and engineers are adapting to the new regime, but now is not the time for complacency as ExxonMobil’s global marine lubricants sales manager Frans Horjus explained: “We are constantly looking ahead at future regulatory changes and providing the lubrication solutions to help them navigate the road ahead.” That includes the latest release from the laboratory of the oil major and oil lubricant supplier – Mobilgard 540 X. The solution is specifically formulated to allow vessel operators the flexibility to use 0.10%, 0.50% sulphur fuels, and liquefied natural gas (LNG). “This is approved for use with all three low-sulphur fuel types and gas validated by WinGD. It is the first-to-market offering in our industry that allows vessel operators to seamlessly switch between these fuels without compromising on quality or performance,” he said.
WinGD has also cleared Total Lubmarine’s TALUSIA UNIVERSAL (BN57) for use with its engines, including those with XD-F technology, following tests on two different vessels fitted with WinGD 6X72 engines. The tests were conducted on split engines comparing TALUSIA UNIVERSAL with a BN40 reference cylinder lube oil (CLO). One test was carried out with compliant VLSFO <0.5%S, the other with compliant ULSFO <0.1%S for 2,350 and 2,000 running hours, respectively. Total Lubmarine’s lubricant was also approved by MAN Energy Solutions in late 2019, for all fuels (liquid and gas) with a sulphur content 0.00%S - 1.50%S.