The problem with Environmentally Acceptable Lubricants is frankly nothing to do with the lubricants at all.
The problem is with the societal rules that say it’s ok to speak in half truths and use misdirection.
The owners don’t want it because they see no benefit for it, the lub. oil companies see it as an opportunity to sell niche products at higher margins, especially excited are the smaller specialist firms who normally don’t get access to the majors but know they can “compete” on a level playing field. But it’s not at all level and not all companies are as concerned about technical performance as they are too busy trying to sell what they have rather than develop products that BOTH meet the regulations and are technically robust in operation for each given application.
The world of the EAL is actually well defined, albeit a bit complicated to the layman, but the term biodegradable is rather poorly understood.
Take Uranium – technically speaking it is degradable as it will in time become benign from a radioactive perspective, but this will take many thousands of years. On the other hand milk which is altogether benign and in everyday use, bio-degrades in days and as a result become of little use. Other materials degrade as a result of biodegradation in ways that can be measured. Mineral oil for instance will biodegrade in the standard OECD 28 day test for biodegradability by about 25%, whereas truly useful oils will demonstrate biodegradability in the same test by values in excess of 85%.
Also biodegradability in of itself is not always desirable – as if one emptied a drum of readily biodegradable milk into a fish pond the demand for oxygen will likely result in insufficient oxygen being present to sustain the fish !
What the discerning shipping company should recognise is that the EAL “problem” may well be an opportunity in disguise. It may be an opportunity to reduce costs! As fully saturated synthetic esters (the better ones for EAL applications), can often sustain greater sump lives as they are more robust in regard to oxidation, they are often better lubricants under boundary conditions reducing wear and they should be, of course, fully compliant with EPA VGP requirements which means they MAY be a candidate for rationalisation of grades – reducing the number of products on board.
However, a cautionary note for machinery designers –
ENSURE THAT ALL REQUIRED FEATURES OF LUBRICATION ARE MET BY THE CHOSEN LUBRICANT PRODUCT –
DO NOT RECOMMEND SOLELY BASED UPON THE REQUIREMENT FOR SIMPLE VISCOMETRIC EQUIVALENCE.
For some interesting background to oil types see below.