Maintaining optimal TBN in marine lubricating oils

Stena Line open innovation challenge

Main Content

Stena Line are seeking novel approaches to maintain an optimal Total Base Number (TBN) in marine lubricating oils. The ideal solution would include best practices for continuous, in-line monitoring of TBN and restoring TBN as needed without reducing the other functional properties of the lubricating oil. 

What's the challenge?

The companies comprising the Swedish-based Stena Sphere represent one of the largest private shipping groups in the world. We are seeking solutions that can be applied to cargo and passenger ships that travel in all of the world’s oceans.

Currently, marine lubricating oils are formulated with TBN levels corresponding to the sulfur in the fuel oil used. Typically, half of the lubricating oil is replaced with fresh oil when the TBN falls below some critical level to avoid corrosion by the acidic combustion by-products associated with high sulfur fuels. 

Replacing and disposing of this used oil is costly, and so we are seeking novel methods to restore the TBN continuously until some other life-limiting factor triggers the need for changing the lubricating oil.  At a minimum, we are seeking a 20% extension in service life for the lubricating oil.

Do you have the solution?

Stena is interested in more cost effective and environmentally friendly solutions to maximize lubrication oil service life while maintaining excellent lubrication and corrosion protection to engine components.

In the ideal case, TBN would be continuously monitored on-line and automatically controlled by accurate dosing of a concentrated feed of a basic material. This could be done in conjunction with on-line measurement and control of other critical lubrication oil properties.  

In contrast with existing solutions, the ideal solution should not require the replacement of a significant portion of the used oil, but would rather restore TBN via a concentrated additive, without significantly impacting the lubrication oil’s viscosity.

We would also consider analysis and control schemes that would be simple to use on board, including manual lubrication oil sampling, TBN measurement, and addition of TBN additives.  A less favorable approach would entail sending oil samples to a centralized in-house laboratory for TBN analysis.

Any solution would need to be consistent with the practical space limitations for installation in existing vessels, and would not require specialized skills or extensive training of operating personnel.

Evaluation criteria

Technical viability - Solutions proposed must be based on sound scientific principles and have laboratory or pilot scale data that demonstrate efficacy.

Scale-up potential - Solutions proposed must have a clear pathway to be application on commercial ships. Solutions already practiced in marine markets have higher value. The ideal partner would have expertise in lubrication oil formulation chemistry and physical properties, and would be able to lead the design and installation of full-scale systems.

Costs - Solutions would need to provide reasonable return on investment, consistent with the anticipated annual savings of 40,000 Euros per vessel.

Ownership - Solutions covered by patents have higher value. At a minimum, proposed solutions must not be prohibited by other patents in the field.

Killer issues - Solutions will not be considered if, in Stena’s opinion:

  • Installation and maintenance costs should not be prohibitive for broad application
  • Proposals lack sufficient supporting laboratory or pilot scale data
  • Solutions don’t adhere to global maritime environmental or safety regulations
  • Solutions would void guarantees from engine suppliers. Approval may be needed.

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