DETROIT – Rerefining technology and waste lubricant feedstocks have improved significantly in recent decades, and the sustainability movement has made the case for rerefined base oils more compelling.
But suppliers still have work to do raising end user comfort levels for using those base oils, according to speakers at a conference here last month.
“Some customers still perceive a performance trade-off,” Shell General Manager of Industry and Transport Technology Jason R. Brown said at Lube Expo North America on March 19, citing findings from a study by Deloitte. “‘Recycled’ carries a negative perception in the marketplace.”
The processes used to recycle used lubricants have evolved a lot over the past several decades. As Blue Tide Environmental Chief Executive Officer Mark Bouldin recounted, in the 1960s and ‘70s, recyclers used an acid treatment and clay filtration technology that only aimed to remove contaminants such as water, sludge and wear particles.
Base stocks produced by this technology were inconsistent in quality, were dark in color and had a very unpleasant odor. They were API Group I oils or in some cases did not meet the specifications for Group I.
The most advanced processors subsequently replaced the acidification part of that technology with vacuum distillation, and then in the 1980s, Philips employed combined hydrotreatment with vacuum distillation to remove impurities such as sulfur, nitrogen, chlorine and heavy metals, yielding base stocks that were lighter in color, had higher viscosity index and no odor.
Just as important as the technology leaps, the quality of used oil feedstocks has also taken leaps in many markets. At the turn of the century, most engine oils in most markets were made primarily with Group I base stocks, though Group II or III stocks may have been mixed in. Today the latest engine oils in developed markets must be made mostly with Group II or III.
“As feedstocks improved in the 2010s, rerefineries were able to make good Group II and Group III base oils,” Valvoline Director of International Research and Development Jesse Dambacher said. “Great feedstocks have allowed reduced processing. The industry is getting to the point where it can make close to Group III without hydrotreating.
Speakers agreed that rerefined base oils now perform on par with virgin base oils, but they also agreed that many end users are not aware of that. But Brown said the sustainability movement is making the market more open to using rerefined oils, and he suggested steps can be taken to ease concerns about quality. For example, using engine oils made with rerefined base oils on racing circuits can demonstrate their performance.