Shipowners should challenge fuel suppliers and reinforce their own fuel-management practices to safeguard sulphur compliance, reports Riviera Maritime Media.
What am I putting into my engines?
ExxonMobil marine fuels venture manager Luca Volta says, “Know your fuel – that is the key to a successful 2020.”
Thankfully, he says, the industry has never been more eager to learn exactly what they are putting into their engines.
ExxonMobil insights
The company has been speaking to customers for the past few months – more than 900 across 11 maritime hubs – as part of its ‘Journey to 2020’ symposium series.
The symposia offered ExxonMobil insights into the concerns and challenges that are playing on the industry’s mind as IMO’s sulphur cap nears.
Journey to 2020: Key takeaways
Now it plans to share what it has learned. The company has produced a guide to switching fuels ahead of 2020 that includes hints and tips for the selection, use and handling of fuels and lubricants.
In April ExxonMobil hosted a webinar, chaired by IBIA director Unni Einemo, in which it revealed some key takeaways from the symposium series, listed below:
- We are heading for a multi-fuel future
- Fuel compatibility will be a concern
- Cat-fine contamination is likely to increase
- Tank cleaning is important and often overlooked
- Know what’s happening in your engine
- Always follow switching best practice
- Select cylinder oils that work with your fuel selection
- LNG will be a part of the fuel mix
- Scrubbers are a viable route to compliance
- Financial management and compliance go hand-in-hand
The hungry marine industry
“I’ve never seen the marine industry as hungry for detail as they are now,” says Mr Volta. “End users are getting really deep into fuels and asking the right questions about what they are putting on board, who has supplied it and the research and formulation that has gone into their fuels and bunker deliveries.”
The attendees sought advice on how to maintain the flexibility to use a mix of compliant fuels marine gas oil (MGO), 0.50% very low-sulphur fuel oil (VLSFO) and 0.10% ultra-low-sulphur fuel oil and what this would mean for handling and storage.
Multi-fuel future
“If you want to go for a multi-grade solution, you’re going to need the flexibility in your tank system to enable it,” says Mr Volta. The feasibility will depend on the configuration of the ship
- the number of receiving tanks,
- nature of the fuel system,
- whether you have heated tanks and
- the nature of the trade.
With a wide range of fuels comes a wide range of fuel characteristics. According to ExxonMobil aviation and marine lubricant global field engineering manager Iain White, matching the required fuel temperatures and viscosities will be a challenge for operators using several fuels on board.
“When it comes to combustion it is critical that fuel is brought to the engine at the right temperature,” says Mr White. “If you are on a distillate, it is already probably too low in viscosity for the typical two-stroke, so we’ve seen vessels installing chillers for use in emission control areas in the past.”
Fuel compatibility will be a concern
The compatibility of fuels will be questioned more as the number of available fuel formulations increases.
When ExxonMobil revealed the availability for its own 0.50% VLSFOs, it took the unprecedented step of assuring their compatibility across global bunker locations. But even here compatibility could be impaired by poor handling and storage, says Mr Volta.
Mixing is assured at up to a ratio of 80:20 and best practices should be applied from bunker to engine. Even today, using existing regular sulphur fuel oil, shipowners would not mix different fuels in a 50:50 ratio.
The issue is even more challenging when using fuels from different ports and suppliers.
“Compatibility is one of the items we’ve debated at great length,” says Mr Volta.
Although the most common compatibility issues arise due to the asphaltenes in residual fuels, distillates can bring their own challenges. For example, mixing two distillates with different cold flow properties can lead to problems.
The new/old issue of cat fines
The potential for cat-fine contamination is expected to increase as new fuel blends enter the market.
- If not removed, these abrasive refinery residues can travel to the engine, blocking filters on the way and causing damage to fuel-injection equipment.
- If they make it to the engine, they can quickly cause severe damage to piston rings and liners.
- ISO 8217:2010 introduced a maximum permissible 60 ppm level for cat fines, a concentration that can be managed by onboard purifiers.
- But high contamination levels mean owners will have to remain vigilant, says Mr White.
“If the cat-fine level is high there is an immediate danger as vessels consume the fuel,” he says.
“Over time cat fines can also precipitate out, building a problem in storage that can come back to bite the operator when those tanks are agitated by bad weather. To help avoid this, shipowners should get fuel testing done with every single batch and keep on top of fuel condition on board.”
To minimise contamination issues, knowing what has been in your tank may be as important as knowing what is there at the moment. Although pure distillates do not contain cat fines, they can have a cleaning effect in tanks that would pick up any cat fines and carry them through the fuel system. This, says Mr White, is another example of how onboard fuel management will become critical from 2020.
Tank cleaning
As part of that fuel-management process and in preparation for compliance, many owners will need to clean their fuel tanks before the 2020 rule comes into force.
According to Mr White, this does more than reduce the risk of contamination. Just 2% of heavy fuel oil left in a tank could push a ship burning 0.50% sulphur fuel into non-compliance.
“It goes back to preparation,” says Mr Van Bouwel. “Every ship is a little different. The ship implementation plan asks owners to consider their fuel storage and tank configuration as well as their fuel management plan. That includes cleaning upfront to make sure you go into the 0.50% sulphur world with a clean tank.”
There are three options for tank cleaning, each effective but with their own challenges.
- Traditional manual cleaning is time consuming and difficult to fit into sailing schedules.
- Best practices suggest that when flushing with distillates, the distillate used should then be disposed of as slop rather than put back through the fuel system.
- Using additives may require a longer timeframe to be effective.
But whichever option owners select, the most important point is to have a plan for starting 2020 with tanks that will allow compliance.
Last line of defence against poor fuel quality
With all this complexity, monitoring throughout the fuel system is becoming increasingly important. This includes checking the fuel coming on board as well as the fuel reaching engines.
ExxonMobil’s solution is its scrape-down oil analysis service, which is now able to give a sulphur reading of the fuel in the engine using X-ray technology.
Mr Volta points out that bunkering fuel that meets the latest ISO 8217 standard, published in 2017, offers the best protection from cat-fine contamination and poor cold flow properties, among other issues.
Mr White describes crew as the last line of defence against poor fuel quality as best practice during onboard treatment is also needed. One important example is in the use of purifiers to protect the engine and fuel system.
“We would usually advise that purifiers are run at the optimum rate, which really means the minimum that they can be run at,” he says. “Consider running two purifiers in parallel if the issue is really bad. And make sure they are running at the right temperature.”
Easing complexity: a linear blend
Amid all that added complexity, there may be some areas where shipowners’ choices are simplified.
Today, many vessels will have two cylinder oils on board:
- one with a base number of 25 (BN25) for use with low-sulphur fuels in ECAs and
- another high-BN oil (BN70 or BN100, for example) for when a vessel is burning high-sulphur fuel oil.
From 2020, owners choosing 0.50% sulphur fuel will require just one cylinder oil.
Do not waste any oil
“Our research has settled at BN40 as being the optimum formulation. Although shipowners will have to manage cylinder oil transition, we are suggesting that mixing is acceptable, it is a linear blend and there should be no need to waste any oil,” reports Mr White.
“Our advice is to err on the high side rather than low for BN. We’ve seen that problems tend to happen either not at all or very slowly if ships continue in a low-sulphur area with high-BN oil, whereas corrosion issues happen very quickly if you use too low BN oil.”
Cylinder lubrication
The cylinder lubrication picture is not entirely straightforward. Ships using scrubbers and high-sulphur fuel oil may still need to keep low-sulphur fuel and low-BN oil on board depending on scrubber restrictions in the ports in which they operate.
And cylinder lubrication for gas engines, another compliance option, will also be slightly different. ExxonMobil is in the process of developing a dedicated cylinder oil for use with LNG.
It is not just technical
The challenge is not just technical but also about financial management, notes Mr Volta. Opting for the fuel that is cheapest will not always help to achieve the lowest total cost of ownership if it does not perform properly.
The key dimensions of a quality fuel, apart from sulphur compliance are
- stability,
- combustion,
- low catalytic fines,
- viscosity and
- compatibility.
Additionally, if ships are found to be non-compliant, reputational damage could be even more costly than buying compliant fuel.
Right questions before stepping for compliance
To make compliance decisions that lead to the lowest cost of ownership requires shipowners to first ask the right questions. Mr Volta concludes saying:
- Know your supplier,
- your onboard handling,
- your fuels and
- your lubricants
- Know the services that go hand-in-hand with those fuels and lubricants, including technical support
- Have an educated discussion and make a conscious choice.
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Source: Riviera Maritime Media
