Additives in lubricant oils need to be fine-tuned to optimise the operations of two-stroke engines burning very low sulphur fuel oil (VLSFO)
Lubricants prevent friction and engine wear, clean piston rings and crowns of debris and neutralise acidity in the fuel mix. These beneficial properties come from additives in the lube oil.
Developments in additive technology were the subject of in depth discussions during the ‘Assessing the added benefits of marine additives and lubricants’ webinar, which was sponsored by Lubrizol.
The webinar was part of Riviera Maritime Media’s Marine Lubricants Webinar Week, held in association with premier partner Castrol.
During the webinar, participants explained additive technology’s place in managing changing and challenging fuel properties, engine designs and vessel operating profiles.
There were presentations by MAN Energy Solutions director of new technologies and two-stroke promotion Kjeld Aabo, Lubrizol technical manager for marine diesel engine oils Ian Bown and Gulf Oil Marine technical manager for Europe and Africa Paul Elliott.
They discussed the additives needed for ultra-low sulphur fuel and the significance of changing fuel availability and requirements for maintaining engine operation.
Mr Aabo said engines operating on VLSFO will be the most predominant in the coming years and additives in lubricant oils will need to be adjusted accordingly.
“Highly fuel-efficient engines with higher pressure and higher temperature require lubricants with matching performance,” Mr Aabo said.
Lubricants help to maintain engine performance to prevent unplanned machinery downtime, lubricating the piston and liner, reducing friction and introducing wear protection to prevent seizures. “Cleanliness of the piston rings and crowns is important to secure an acceptable time between overhaul of the cylinder units,” said Mr Aabo.
Additives in lubricants also neutralise acids and oxidation products and keep the piston, piston rings, ringlands and liner clean.
Mr Bown said there were additive design challenges because of the different engines, fuels and operational requirements. Challenges include the temperature these oils work in, properties of new fuels and maintenance requirements of engines.
The majority of constituents of lubricants are base oils, but the cleaning and acid neutralisation comes from the performance package, said Mr Bown.
With VLSFO, there are different requirements from these packages and challenges.
“With different chemistry, modifications and additives we could overcome these issues,” said Mr Bown. He said new bench tests of lubricant oils with engines are required because of higher VLSFO consumption in shipping.
Lubrizol has developed a hot tube test method which incorporates VLSFO and shows better correlation to the engine test results.
Mr Elliott said further challenges will be coming to lubricant oil development and testing as shipping begins to use different fuels to lower carbon emissions. These fuels could involve dual-fuel engines to burn LNG, methanol, LPG and bio-based distillates. “Future oils will depend on the choice of fuel,” he said. “Additives will be an essential part of the mix.”
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Webinar panel was: Lubrizol technical manager for marine diesel engine oils Ian Bown, MAN Energy Solutions director of new technologies and two-stroke promotion Kjeld Aabo, and Gulf Oil Marine technical manager for Europe and Africa Paul Elliott.