Advice from the major fuel suppliers and our own extensive laboratory testing has confirmed that compatibility and stability in VLSFO will be unpredictable. Many of the ISO 8217 compliant fuels will still cause significant issues on-board.
Over 35 ISO 8217 specification compliant fuel samples were tested, using Turbiscan, for stability and compatibility. The results show:
40% of base VLSFO fuels are currently unstable when they are sold
56% of VLSFO fuels become highly unstable when mixed in a tank
Incompatibility occurs irrespective of mix ratio (50:50, 10:90, 90:10 etc)
90% fuels pre-treated with Octamar™ HF10 Plus showed excellent stabilityA sample ISO 8271 compliant fuel is mixed with itself and five other samples in different ratios to test for both stability and compatibility.
All six fuel samples had a high risk of instability. When tested with the same fuel samples treated with OctamarTM HF-10 PLUS every fuel combination tested positive with no risk of instability.
The Turbiscan Reserve Stability test (one of the most widely used tests in marine fuel labs) predicts the likelihood and speed at which a fuel will destabilise and produce excessive sludge. A Reserve Stability Number (RSN) above 3.0 means there is a high risk of instability.
There are vast differences in VLSFO on the market and the quality varies from port to port and batch to batch. Although these fuels are all classified under the same specification, they cannot be stored, handled or heated in the same way.
There are:
These images show just what can happen. This VLSFO was supplied well within ISO 8217 specification.
It was loaded into completely clean tanks and fuel system, yet failed within four hours. Total engine failure soon followed. This case is not a one-off. There have been a number of reports of fuel system failure and engine damage when using ‘on spec’ fuels.
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By pre-treating VLSFO you can solve the problem of fuel instability and tank mix incompatibility. Octamar™ HF-10 PLUS and Octamar™ Ultra HF are the only additives that protect against both distillate sludge and asphaltene sludge.
Octamar™ HF-10 Plus keeps your engine running by stabilising fuel blends and reducing sludge formation.
Octamar™ Ultra HF provides a complete solution for VLSFO. It keeps your engine running by improving fuel blend stability and combustion while reducing soot formation.
The Turbiscan Reserve Stability test (one of the most widely used tests in marine fuel labs) predicts the likelihood and speed at which a fuel will destabilise and produce excessive sludge. A Reserve Stability Number (RSN) above 3.0 means there is a high risk of instability.
Our laboratories have tested a number of compliant fuels for stability and compatibility. The tables opposite show the results of six samples of ISO 8271 compliant fuel mixed with itself and five other samples in three different ratios, tested using Turbiscan for both stability and compatibility. The tables show all the results. All combinations of the fuel samples had a high risk of instability. When tested once treated with OctamarTM HF-10 PLUS every fuel combination tested positive with no risk of instability.
The cost of VLSFO instability is not just a full tank of fuel. Returning the vessel to port, repairing and cleaning the engine system and refuelling can run into many hundreds of thousands of dollars, before you even factor in operational losses.
Claims against fuel suppliers are rarely successful if their fuel meets specification. The oil majors have also made it clear they will not take responsibility for fuel stability after a fuel’s expiry date. This rests squarely with ship operators. So, for the operators’ peace of mind and significantly improved fuel stability, pre-treating fuel with Octamar™ HF-10 PLUS or Octamar™ Ultra HF is the only solution.
Pre-treating fuel with Octamar™ HF-10 PLUS or Octamar™ Ultra HF is highly effective at stabilising VLSFO. However, it will not reverse sludge formation. Once a fuel has chemically broken down there is no way to reverse the process.
To reduce the level of sulphur in fuel, VLSFO typically contains up to 90% distillates. This has been demonstrated through SARA analysis.
These distillates most likely come from secondary refining streams to reduce cost and they are highly unstable, more susceptible to aging and prone to rapid oxidisation, especially when mixed or heated. The result is a type of sludge formation that is very different from traditional asphaltene sludge.
To stabilise it requires a different sort of chemistry.
Since mid-November there has been more and more vessels loading IMO 2020 compliant VLSFO, and particularly in December vessels have been starting to consume this fuel as their ROB of HSHFO is depleted. There have been numerous reports of issues encountered during changeover as the crews onboard learn to deal with these new fuels, however not all issues are related to fuel handing onboard and are due to the chemical nature of the fuel.
As global market leader in marine fuel testing and bunker quantity surveys, Veritas Petroleum Services (VPS) has tested the most VLSFO samples in the market to-date and has witnessed first-hand what these very-low sulphur fuels have to offer. Based on this data, VPS is introducing VLSFO Insights a monthly subscription-based service, where technical expertise is combined with its proprietary database of fuel oil and distillate samples, to derive special insights for its users.
Certain flag states have been calling for an experience building phase based around safety concerns of an unknown fuel, some are saying it is a thinly veiled attempt to delay 2020.
A number of newsletters will be produced to provide more information around how to prepare for IMO 2020 in the most cost effective method. Download the latest here, or register for free copies below.
Our focus is on supporting the fuel industry as it adapts to new opportunities and challenges. By leveraging our experience and expertise in different markets, we create the reliable, highly functional and extremely competitive packages our customers demand. Our strength is our knowledge of fuel and how to improve fuel performance for different applications.
This always keeps us one step ahead of our competitors. Our products are tried and tested in many different environments whether at sea, on the road or in the air. With a worldwide network spanning 23 countries and 2000 employees, we can deliver global solutions geared to local customer needs.
North P&I Club is a leading marine mutual liability insurer providing P&I, FD&D, war risks and ancillary insurance to 147 million GT of owned tonnage and 60 million GT of chartered tonnage (at February 2019).
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