The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is a single worldwide system that was introduced by the United Nations to help remove confusion about the different ways the hazardous properties of chemicals were assessed and classified via a number of historical national schemes. It also clarifies how information about these hazards is communicated to users through labels or safety data sheets.
GHS aims to introduce the same criteria for classifying chemicals according to their health, environmental and physical hazards and the same hazard communication requirements for labeling and safety data sheets across the globe. While GHS is not legally binding, the international agreement means countries must create local or national legislation to implement it.
What It Means for Marine Lubes
In the marine lubricants world, one chemical that is impacted by GHS is tetrapropenyl phenol (TPP), which has been classified as a reprotoxin. TPP is used in the synthesis of phenate detergents, which help provide high-temperature performance in marine diesel cylinder lubricants.
Reprotoxins are substances that are known or presumed to have an adverse effect on the reproductive ability or development in humans. Due to a European Union process of harmonization of the classification for TPP, it must be classified as a category 1B reproductive toxin by March 1, 2018.
As a result, the threshold for labeling TPP-containing formulations will decrease significantly in much of Europe, Middle East, Africa and Asia Pacific, compared to the previous classification as a category 2 reproductive toxin. This means marine lubricants that contain TPP levels equal to or greater than 0.3 percent by mass will need to carry the appropriate GHS pictogram and hazard phrase. In some countries, notably the United States and Canada, the classification level for a reproductive toxin is even lower at 0.1 percent by mass.
MDCL Evolution
Marine diesel cylinder lubricants are formulated to protect large two-stroke marine engines, which operate under harsh conditions and typically burn low-quality, high-sulfur fuel. Additive packages can contain high levels of overbased detergents, delivering base to neutralize acids and organic surfactant (soap) to provide cleaning properties. MDCLs mainly use detergents with an overbased calcium core and different soap types, including alkylated salicylate, sulfonate or phenate.
In modern engines, combustion by-products can form deposits when exposed to high temperatures in the piston ring zone, which can cause ring sticking and lead to scuffing and excessive cylinder liner wear. Phenate components are used to control these deposits.
However, the downside of phenate detergents is that they can contain residual TPP at levels that mean even the finished MDCL must be labeled as reprotoxic. Infineum initiated a project to find a chemistry capable of delivering the required high-temperature performance without the health and safety issues associated with the use of prior generation phenates.
Reprotoxic Label-Free MDCL
Infineum developed a detergent chemistry that withstands the high temperatures in marine engines, but that contains TPP levels below the labeling threshold. To assess the performance of the new detergent, three SAE 50 test oils were formulated in API Group I base stocks with a base number of 70.
The performance of these reprotoxic label-free lubricants was compared to that of commercially available MDCL reference oils that, under the new regulations, would carry a reprotoxic label. The oils were evaluated in a number of tests, including the Komatsu Hot Tube Test, Panel Coker test, High Frequency Reciprocating Rig (HFRR) and Pressure Differential Scanning Calorimetry (CEC-IL-085).
The Bolnes 1DNL engine test is generally used to screen cylinder oils prior to their evaluation in the field. Oils are assessed for how well they control wear and fouling of the piston, piston rings and cylinder liner. In this test, the label-free oils demonstrated mechanical wear performance equivalent to or better than the commercial oils.
The results of bench and engine tests showed that, in terms of thermal stability, wear, oxidation and cleanliness, the test oils can provide performance equivalent to, or better than, existing commercial oils. To confirm the laboratory results, the next step was to evaluate the test oils in the field.
Field Test Results
The test oils were assessed in over 4,100 hours of field operation in an 8749 TEU container ship with a deadweight of 103,800 tons, powered by a MAN B&W Tier 2 12K98ME-6 engine that develops about 68,640 kilowatts of power. The engine was run on heavy fuel oil, except when in emission control areas, and was slow steaming for a significant period with one turbocharger cut out. Test cylinders were segregated so test and reference oils could be compared.
At the end of the trial, all liners were found to be in good condition, free of deposits and lacquer. In addition, on-board liner scan analysis did not report any concerns or detect any scuffing. The pistons were also very clean with minimal deposits in the grooves and lands.
These results indicate that label-free formulations can deliver equivalent performance in terms of cleanliness to commercial MDCLs. In addition, in cylinder drain oil analysis, the label-free technologies delivered similar performance to the commercial oil.
The results of this study indicate that MDCLs can be reformulated to avoid the reprotoxicity concerns caused by the presence of TPP without compromising performance. All of the oils tested have now been OEM approved and are available as reprotoxic label-free options for MDCL applications.
Luciana Angonesi and Malgorzata Maranska are Lubes Development Technologists at Infineum International Ltd., based in Long Wittenham, Oxfordshire, United Kingdom.