The quality of LSFO – Stability

The bunker testing agencies and other bunker experts tell me that there are some serious problems with the quality of LSFO. One of these problems seems to be stability. So what is stability?

Marine residual fuels are a blend of all sorts residues and side streams produced from distillation and conversion processes when crude oil is refined. All of these fuel components have different qualities. Some have high density and low viscosity and others high viscosity and moderate density. Some have high sulphur and some low.

The marine residual fuel producer has to take any number of these different quality components and blend them together to achieve a mixture that meets the quality characteristics set out in the ISO 8217 fuel standard.

In the past the main quality targets were viscosity and density but now the demand for LSFO (less than 1.5% sulphur) is rising and sulphur has become a key blend target and viscosity and density secondary targets.

On the face of it, that looks OK, but it seems that this change in blend targets sometimes results in the production of a fuel which “ falls apart” when it is heated and treated on board ship. This is probably due to the finished fuel having a poor stability and/or a lack of reserve stability.

Fuels with poor stability characteristics tend to allow asphaltenes in the fuel to drop out of suspension creating heavy sludge, particularly during purification and filtration on board ship. So the problem seems to be that to achieve a low sulphur blend the producer sometimes gets it wrong and mixes some components together which are not compatible and as a result the ability of the fuel to retain stable under normal ship board conditions is lost.

So what can happen on a ship when the purifiers and filters become totally blocked with sludge? Unless the ship’s crew can keep up with the high frequency of cleaning filters and centrifuges the amount of treated will be less than that required by the engines. The ship will then slow down and perhaps, under severe conditions stop.

This is not a pleasant thought if the ship is in heavy seas or trying to navigate in a busy shipping lane.

Surely finished fuels can be tested for stability before they are delivered to ships? And ships could take samples of the fuel at the time of delivery and use a simple on board test kit to establish stability. If they found an unstable fuel they could sit tight, in port until the problem has been resolved. Yes or No?

Who knows what the sulphur content is?

What a mess out there. Confusion, fear, indifference and plain old ignorance and the serious stuff hasn’t even hit the fan yet. That will happen in around five months when the regulators turn up the environmental heat again and the North Sea SOx Emission Control Area (SECA) kicks in.

In a SECA, the sulphur content of fuel oil used onboard ships must not exceed 1.50% m/m, so if your ship is operating in the North Sea and from November 22 it will have to be using fuel with a sulphur content below 1.5% as opposed to 4.5% allowed on the high seas.

So how will you know that the sulphur content of the fuel you are using is below 1.5%? Surely you ask the supplier to give you low sulphur fuel and he does – simple as that. The bunker receipt must provide the actual sulphur content, so will you hang your hat on that?

Let’s say you did and some authority or other decided to check the sulphur content of the fuel in your service tank and found that your ship was using fuel with a sulphur content of 1.7% inside the SECA. Who knows what the penalty would be but the ship would probably be detained until new compliant fuel was taken on board.

This could take a few days to sort out and you may even be faced with taking of the non-compliant fuel to make space for the new bunkers. More high costs and delays! Then you have to try and recover your costs from the supplier.

But let’s assume that the Marpol sample issued by the supplier ( also a requirement under Marpol regulations) is tested and found to have a sulphur content below 1.5%. Imagine the drama and costs involved with trying to figure out what went wrong.

Of course, if your ship’s staff had taken a representative sample during the delivery at your receiving manifold and had sent this for routine testing you would have good evidence as to the true quality of the fuel supplied and be in a much better position to recover costs from the supplier.

Can anybody out there tell me why only about 50% of ships take routine bunker fuel samples? Apart from the relatively new sulphur issue, if we can rely on numerous alerts and updates from the bunker testing agencies, seriously bad fuels are far from uncommon and many result in engine damage and ship delays.

So if 50% of ships are not testing then it must be the case that 50% of ships are running a high risk of using poor quality fuel and the first they will know about it is when the engines stop and the lights go out. A frightening thought for safety at sea.