SECTOR FOCUS:
BASE OILS
Environmental benefits from base oils in heavy duty engine oil Céline Thompson, Senior Customer Technical Service Specialist, Afton Chemical Reducing environmental impact is a clear target for governments, companies, and consumers worldwide and the heavy duty engine oil market is no exception. Afton explores how base oils can contribute to finished lubricant performance and additional environmental benefits in the growing top tier, premium and mainline heavy duty engine oil (HDEO) segments. The global legislative agenda has been pushing faster and harder to reduce carbon footprints, minimise emissions, improve resource conservation and create a truly circular economy. In heavy commercial vehicle applications, the pressure to reduce carbon dioxide emissions has driven widespread technological advances. With the latest hardware needing greater protection and performance than ever from lubricants, the spotlight is on how base oil selection can support this drive for sustainability. Why base oil matters By far the largest constituent by volume of finished lubricants is base oil - making up anywhere from 75-90% of a finished HDEO. The remainder is a blend of performance additives such as anti-wear additives, detergents, dispersants and antioxidants and viscosity modifiers. Mineral base oils that are refined from crude oil – Group I, II and III oils – can contain up to 500 different molecular types. As the proportions of each type influence the finished lubricant’s inherent properties, the choice of base oil is very important. Governments mandating minimum oil specifications have already rendered the lower tier HDEO industry specification obsolete in many countries. As the lower tier segment has diminished in importance, demand for Group I base stocks has dwindled, almost halving in the past decade.
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LUBE MAGAZINE NO.169 JUNE 2022
Figure 1: Properties of chemical types.
Lower tier engine oils based on Group I base stocks are still widely used in Off Road vehicles in developing markets. However, the drive for sustainability means that Off Road emissions legislation is likely to keep following that for On Road commercial vehicles. Base oil trends In the meantime, demand is growing for the more highly refined base oils – Group II and even Group III. Being lower than Group I oils in aromatic content, and higher in naphthenic and paraffin molecules, Group II oils deliver a better all-round balance of performance, with sufficient solvency for blending performance additives, all typically at a lower cost than Group III base oils according to key market indices. This positions Group II perfectly for the mainline (API CH-4 / CI-4) and premium (API CK-4) HDEO segments. Not surprisingly, the Group II share of global base oil production is growing. Group III is also increasing in importance. The naturally high viscosity index and excellent oxidation resistance of Group III base oils make them well suited to the more nuanced requirements of top tier HDEO. As emissions legislation becomes increasingly stringent, Group III oils will likely see demand continuing to rise. In the United States, the American Petroleum Institute is expected to launch its PC-12 specification in 2027.