Sustainable Marine Fuels Require Lube Changes


Sustainable Marine Fuels Require Lube Changes
An overhead view of the main engine of a large tanker. © Vallehr

The push to halt climate change is causing the shipping industry to shift to new types of fuels, and industry stakeholders should collaborate to determine the performance needs for the next generation of cylinder oils, speakers said during an online webinar last week.

The marine industry is in the midst of transitioning to engines using new fuel types, including drop-in biofuels, methanol, ammonia and hydrogen.

“New engine designs and [a] multi-fuel future bring complexity and new demands on cylinder lubricants,” ExxonMobil Marine Lubricants Engineering Manager for Europe, Africa and the Middle East said Filippos Athanassiadis said during a Riviera Maritime Media webinar Sept. 5. “New lubricant technologies are needed and are being developed and deployed.”

Athanassiadis noted that the international Maritime Organization aims to reduce greenhouse gas emissions from international shipping by at least 20% – striving for 30% – and then moving to a 70% reduction – striving for 80% – by 2040, compared to 2008.

He emphasized the importance of continued collaboration, working with marine industry stakeholders and investing in technologies to ensure longterm reliable engine performance.

Athanassiadis highlighted emerging types of cylinder oil, including Man Energy Solutions’ Category II product category, which has a special focus on cleaning ability, and Winterthur Gas & Diesel’s dual fuel validated oils.

Don Gregory, managing director for Azurtane Sustainable Maritime Solutions, said that new fuels currently constitute less than 0.1% of global fuel bunkers but that theoretical challenges presented by future adoption of such fuels has become clear. One implication is in the impacts and possible changes in combustion rate and heat release characteristics in ship engines, which could impact cylinder oils.

Another implication is in how the new fuels will perform under the variation in different ship engine loads and dynamic conditions. He pointed out that marine diesel engines differ in terms of whether they’re used for main propulsion or auxiliary purposes, and they are often run under different power utilization situations.

The tendency of new fuels towards incomplete combustion is another difference with implications for lubricant performance. “For example, a heavy fuel oil has quite an incandescent flame, and therefore has a radiated heat profile,” he explained. “A natural gas engine with blue flame has a much more conduction effect in the release of heat, and that may affect liner surface and the lube oil.” Incomplete combustion can also result in deposits, he added.

Variations between batches of the new fuels is another factor, he said, and will continue to highlight the importance of monitoring trunk piston engine oil performance and consumption as a good practice critical to minimizing loss.

It will remain important to conduct monthly inspections, he said, checking for internal cleanliness, deposits and wear. Used oil analysis once a week is also recommended, he added.