Use of high base number (BN) cylinder oils in the shipping industry may continue to increase, even if it is not always necessary, said Gulf Oil Marine global technology manager Don Gregory, speaking at Riviera’s Maritime Air Pollution Conference, Americas in Miami
“Back in the 1960s, we would go to a petrol station and we would buy diesel with 2% sulphur in it, and the base oil would have been 15 BN and the engine would not corrode away… and I think [use of higher BN oils] is partially driven by the additive companies, who have been more relaxed in the way they are treating the oils for 2020.”
As Mr Gregory recounted, the call for higher base number cylinder oils came when OEMs approached lubricants producers with a problem: dirty engines.
Typical cylinder oil blends are made up of 60% to 70% base oil and up to 40% additives, he said. Producing cylinder lubricating oils with a higher base number (BN) directly affects the amount of acid neutralised during use but also increases the cost.
With the OEMs calling for engine cleanliness, Mr Gregory anticipates a wave of change coming in cylinder oil production. According to him, some of these changes could include: cylinder oils ranging from 15 BN to 140 BN, ashless additives replacing over-based detergent additives and improvements in cylinder cleanliness.
Ashless additives are much better at acid neutralisation and surface cleaning, Mr Gregory said, and they are known to successfully hold contaminants in suspension. However, he said the logistics of lubricant production and distribution will become more complicated because cylinders will require three or four additive packs instead of two.
Mr Gregory said the focus of cylinder oil production is likely to shift from cost to performance, with owners choosing cylinder oils based on how they work in their engines and not based on how much money it saves them.
Ending with a qualification, he implied his predicted changes, if they happen, will show up in the near-term.
“These are just the things that I think will happen. In the coming months, we will see if I am proven wrong or right.”