Many Operators Unaware of Potentially Catastrophic Bunker Related Engine Wear Problems, ExxonMobil Data Shows

Iain White, Global Marketing Manager at ExxonMobil Marine. Image Credit: ExxonMobil

It is generally understood that burning low quality bunkers can lead to excessive and potentially catastrophic engine wear, but a recent analysis by ExxonMobil of data collected from its MobilGard Cylinder Condition Monitoring (CCM) service shows many operators are unaware that the bunkers they burn are exposing them to the risk of engine failure.

Many others are simply wasting money by over lubricating the engine, the data showed.

The database contains analysis of some 400,000 oil samples, collected from a programme that has been in place for 15 years, and a recent review of the 2016 data indicated 43 percent of vessels were shown to have an issue with cat fines causing excessive engine wear and, ultimately, the potential for engine failure.

Fuel quality analysis can identify when bunkers have high levels of cat fines, in effect giving operators advanced warning of potential issues, but ExxonMobil says that in half of the cases it identified the operator was completely unaware of any problems.

"Without monitoring you just don't know that wear is happening," said Iain White, Global Marketing Manager at ExxonMobil Marine, who recently spoke to Ship & Bunker about the analysis.

White also highlighted the fact that the limits for cat fines in ISO 8217 not only vary by revision year, even on-spec bunkers can be well above manufacturer recommended levels for the engine.

"A lot of fuel today is sold against the 2005 spec which has a maximum level for Al+Si of 80 mg/kg, but for 2010 and beyond that is lowered to 60 mg/kg. It is a significant difference and one that I think is often overlooked, but the recommended limit at the inlet of many engines from the manufacturer is 15 mg/kg as an absolute max, so even if you bought on-spec fuel you really need to have the purifiers working properly," he said.

"Of course what we're picking up is not that there are cat fines in existence in the fuel, what we're picking up is the wear they've created in the engine, and half of the people who have got this fundamental wear problem don't know they've got it. So I think what we're seeing is evidence that there are many operators out there that are not operating their purifiers properly."

Problems with high levels of cat fines are often associated with fuel blending, which is why such quality problems spiked with the introduction of the 1.0 percent sulfur IFO blends to meet Emissions Control Area (ECA) regulations.

When the rules tightened in 2015 to 0.1 percent max sulfur those HFO blends became obsolete and there was a corresponding reduction in the related fuel quality issues.

"If you ask the testing agencies about the fuel quality today, they'll tell you they see fuel quality having got better compared to the time when the ECA fuel sulfur level was 1.0 percent. The reason is there was a lot of blending going on, and that created cat fines problems," said White.

"A lot of that's gone away now and the cat fines problems in fuel samples are as low as they've practically been in recent years, yet we're still picking up evidence of a lot of cat fines problems in the engines. In 2020, when the new 0.50 percent global cap comes in, it's likely that problems will return because there's going to be a lot of blending taking place to produce the new compliant fuels.

"So while it's too early to say exactly what's going on from a fuels perspective, it's likely from 2020 that we will see an increase in cat fines levels like we saw before. Operators just won't know that's happening in their engines if they're not doing this monitoring."

Lube Feed Rates

In today's market, keeping a tight control over costs is at the forefront of almost every operator's mind, so it is surprising to learn that another headline figure from ExxonMobil's analysis is that 50 percent of vessels are not operating at optimal lube feed rates.

The most common scenario is that money is being wasted through over-lubrication.

"We always felt this was the case, but today the reality is there is no way of getting your feed rate correct without this monitoring," said White.

"In the old days it was fairly straight forward and we could make a recommendation just about by knowing what the engine type was, but today's engines are specified for ships that are probably not going to be operating at full load, and each engine is tuned to operate at the specific lower load level they want to operate at. Essentially it means that every engine is different and there's just no way of knowing by looking at the model number how it's actually going to work. So it's absolutely critical that people do the monitoring."

In essence, MobilGard CCM can almost be considered as an insurance policy: It tells the operator if they have the right cylinder oil and feed rate, and then makes sure nothing goes adrift if, for example, the sulfur levels in the fuel change. After that, it guards against excessive engine wear and alerts them to wear that could lead to potentially catastrophic damage.

The question, of course, is what is the cost of this insurance.

"Usually what you find is the programme more than pays for itself. For one, half the people are not using the right feed rate," said White, so there is an immediate reduction in operating cost when this is corrected.

"But at the other end of the scale, the cylinder liners on a large box ship could cost as much as $1 million to replace due to excessive wear. They should last the life of the ship or longer if properly looked after."