13 December 2019

Group III base oil interchange makes sense, but only for commodity markets

Written by Chris Castanien
Published in Blog posts under Base oils

Our expectations of modern vehicles grow each year. From performance to fuel economy and GHG emissions, modern technologies push the boundaries of what was previously seen as possible. But progress also creates greater complexity for base oil blenders and marketers as it forces a move to lower viscosities and the use of Group III/III+/IV base oils.

At the recent 15th ICIS Pan American Base Oil Lubricants Conference, I presented a deeper dive into the ramifications of this move – blenders seeking relief through base oil interchange (BOI). While certainly applying BOI on a broad scale would help them, the costs of developing all of the essential supporting data along with the preferences of other stakeholders suggest such any relaxation beyond the American Petroleum Institute (API) administered specifications seems unlikely.

Putting products to the test

In a modern setting, four specification requirements drive base oil selection. From the perspective of engine performance and fuel economy, the essential ones are High Temperature High Shear Viscosity and Kinematic Viscosity. Then there are also base stock specific characteristics that drive base stock group selection – specifically, Volatility and Cold Crank Simulator Performance (CCS).

Volatility, as measured by the Noack test, is a key concern for OEMs whose engines operate at high temperatures and need low volatility oils to enable long drain intervals. Balancing volatility with the second criterion, CCS – based on a 1964 engine cold start test that might be perceived as outdated for modern engines – forces formulators to select Group III, III+ and IV base stocks.

Because different OEMs have different cold temperature and volatility requirements, meeting multiple low viscosity OEM standards requires blenders inventory more than one synthetic oil (III/III+/IV) base stock slate. From a blender’s perspective, this creates challenges, one of them being adequate tankage and the need to select broadly qualified slates. 

The varied views of industry stakeholders

One solution to this problem might be to allow more flexible guidelines governing Group III BOI. Blenders and additive companies argue that extensive testing conducted with the introduction of new API specs – itself both costly and demanding in terms of resources and manpower – and the resulting data support the adoption of BOI. However, not all industry players are willing to provide broad BOI outside API specs without extensive supporting data. 

In terms of adopting BOI for Group III base oils, differentiated views and expectations among key industry stakeholders complicate matters. Each has their reasons for supporting or opposing its wider adoption:

  • OEMs perspective: Data proves performance, so run the test! In other words, BOI should be limited, but can be permitted when enough data-based statistical proof is provided.
  • Additive company perspective: BOI is important for commodity specs to reduce overall program costs but is impractical for elite OEM specs, which require expensive and lengthy development.
  • Base oil marketers with approvals perspective: BOI reduces the return on co-development with additive companies and aids participants unable or unwilling to invest in specialized OEM approvals.
  • Lubricant blender perspective: BOI is beneficial as it can solve logistical problems and allow cost savings through spot purchases of base stocks.

Broad BOI is supported by all industry parties for commodity specs such as API specs. What is more, with API coordination and anti-trust protection, it is possible to generate more than 10 million dollars’ worth of data to support interchange and viscosity grade read across for each of the latest specification’s 7 tests. But this is simply not the case for more specialized OEM specifications. Further, the expanding range of Group III marketers – standard Group III, III+, re-refiners, Fischer-Tropsch Gas & Coal to Liquid as well as bio-lubricants – makes interchange increasingly difficult.

Where does this leave us? Hopefully, my blog not only provides a good explanation of my view on Group III BOI, but also sparks a meaningful discussion. Now’s your opportunity to speak up and comment – do you share my opinion or do you see a different future of BOI for Group III base oils?

Read more industry news and insights on sustainability and renewables on our website: www.neste.com/companies/solutions/base-oils/insights

Chris Castanien
Chris Castanien
Technical Service Manager, Neste