The North P&I Club on Monday (4 May) published an article on the various unforeseen problems that have emerged with the handling and use of IMO 2020 compliant fuel along with some expert opinions on how to minimise damage to vessels:
The introduction of the 0.50% IMO global sulphur cap on 1 January was always going to make 2020 a challenging year. When we entered this new era of environmental legislation, one of the big unknowns was the characteristics of new compliant fuels.
Early experiences suggest that the shipping industry has adapted well to the switch to the new very-low-sulphur fuel oil (VLSFO) products, but the huge variability in their characteristics has brought issues.
Here, we look at some of the problems that have arisen with the handling and use of VLSFOs and we ask the experts for their opinions.
In very simple terms, an unstable fuel can cause sludge to form. This sludge can block pipes, choke fuel filters and solidify in tanks. In extreme cases it can damage piston rings and fuel pumps.
Many VLSFO products are blends of different components. If there is a mixture of aromatic and paraffinic blend components, it increases the risk of instability.
Dealing with the consequences of an unstable fuel often requires the crew to work long hours over several days to keep the vessel moving, carrying out labour-intensive and dirty tasks such as cleaning centrifugal separators and removing blockages. This is likely to lead to delays in the vessel’s schedule. In extreme cases, there have been losses in propulsion which is of course a big danger.
The usual test for stability is Total Sediment Potential (TSP). This is carried out by fuel testing laboratories as part of the suite of tests for checking fuel quality against the parameters of ISO 8217. If the TSP is greater than 0.10% (by mass), then it is at higher risk of becoming unstable.
Since VLSFO products hit the market, fuels are failing on high sediment levels more frequently.
The images below show a very recent example of high sediment fuel. It’s clear to see why it would be difficult to pump this fuel around the vessel.
Short life span
There are reported cases where the VLSFO product met ISO 8217 specification limits for TSP at time of bunkering and subsequently became unstable within a matter of weeks.
The shelf life of some fuels has decreased significantly, which couldn’t come at a worse time when some operators are placing their vessels into lay-up because of the economic impact of the COVID-19 pandemic.
Michael Banning of fuel additive specialists Innospec told us: “Some blend components come from unstable refinery streams and can result in ‘distillate aging’; a chemical process that can produce sediments, gums and polymers. On vessels, it is most commonly triggered by a rise in fuel temperature, such as heating during storage or when passed through a centrifugal separator. In general, a lower viscosity (below 100cSt) indicates a higher proportion of distillates components, leaving them more susceptible to distillate aging.”
The aging process can be prevented but not reversed by using additives. As always, it is very important that additives are used in consultation with the provider.
Confusing cold flow properties
VLSFOs with a high paraffinic content are more vulnerable to wax formation if the temperature drops below a certain point.
As we discussed in our article “New fuels and heat sensitive cargoes” in Signals 119, the traditional “Pour Point + 10°C” rule of thumb for determining fuel storage temperature isn’t always reliable for VLSFOs. Depending on a fuel’s paraffinic content, there is a risk that wax can still form at temperatures higher than this.
Which is why the fuel testing company Veritas Petroleum Services (VPS) uses the wax appearance temperature (WAT) and wax disappearance temperature (WDT) tests to assist shipowners in identifying suitable storage temperatures of fuel.
Steve Bee of VPS told us that the WAT of a VLSFO can be up to 22°C higher than its pour point. Furthermore, the WDT is currently on average 11°C higher than the WAT. With a wealth of test data at their disposal, VPS have found that around three-quarters VLSFOs tested had a WAT between 31-40°C, which emphasises the importance of storing the fuel at the right temperature to avoid waxing.
Think before heating
Getting the right fuel temperatures for storage, treatment and burning is vital to prevent any operational problems on board.
VPS have provided some key points to remember when determining these temperatures for VLSFOs:
Accelerated engine liner wear
We have seen an increase in reported engine liner wear, and this is supported by industry feedback and a recent VPS whitepaper. VPS suspect that recent engine damage on vessels burning VLSFOs may be related to the cylinder oil used.
The reduced sulphur content in fuels means less acids forming during combustion. This has led to a change to cylinder lubricating oils with a lower base number (BN), which is a measure of the oil’s ability to neutralise acids from this combustion process. If the BN is too high, it can result in calcium compounds being deposited on the top of the piston crown. These hard deposits are abrasive and can cause liner wear, scuffing or piston ring breakage.
The reduction from 70BN to 40BN cylinder oil may not be enough, so further reductions may be required in accordance with engine makers and cylinder oil providers.
Check your wear
The more you monitor your engine and how it is reacting to changes in fuels, cylinder oil and feed rate, the better chance you have of preventing damage.
Scrape down analysis is a great way to measure liner wear in the early stages and ‘fine-tune’ cylinder oil feed rate.
The frequency of scavenge port inspections should be increased when new cylinder oils are being used or different fuels are being consumed.
VPS has recently issued several bunker alerts where flashpoints have been below 60°C, which is the minimum temperature required under SOLAS.
Some industry experts have questioned whether reduced car and aviation fuel usage during the COVID-19 pandemic has led to refineries pushing out more volatile blends made up from this lower-than-normal priced fuel.
If your fuel has been tested with a flashpoint below 60°C, then you must inform your classification society and flag State and be guided by their advice.
Read more in our dedicated 2020 sulphur cap expertise area here.
Thanks to the following for their help with this article:
Michael Banning – Innospec Fuel Specialities LLC
Steve Bee & Ian Crutchley – VPS Fuel Testing Services
Photo credit and source: North P&I Club
Published: 5 August, 2020
Caroline Yang, President of SSA, addresses issues earlier raised by players; including PMC No. 04, the seven-day restriction, contactless bunkering, sampling point, hose connection, and more.
IBIA Asia, ABIS, sources from Singapore’s bunkering and surveying companies, and an industry veteran share with Manifold Times the issues expected from MPA’s latest Covid-19 measures.
The top three positive movers in the 2020 bunker supplier list are Hong Lam Fuels Pte Ltd (+13); Chevron Singapore Pte Ltd (+12); and SK Energy International (+8), according to MPA list.
‘We will operate in the Singapore bunkering market from the Tokyo, with support from local staff at Sumitomo Corporation Singapore,’ source tells Manifold Times.
Changes include abolishing advance declaration of bunkers as dangerous cargo, reducing pilotage fees on vessels receiving bunkers, and a ‘whitelist’ system for bunker tankers.
Claim relates to deliveries of MGO to the vessels Pacific Diligence, Pacific Valkyrie, Pacific Defiance, Crest Alpha 1, and Pacific Warlock between March 2020 to April 2020.