Where are lubricants headed?

November/December 2020

• The shift toward sustainability and using green chemistry to derive new base oils made from renewable resources will continue.
• Electric vehicles (EVs) will require smaller quantities of highly specialized lubricants as opposed to large quantities of standard lubricants currently used for internal combustion engine vehicles.
• As EVs partially replace internal combustion engine vehicles, the volume production of lubricants will decrease, but new specialized EV lubricants will provide more value to companies that develop them. On the other hand, the International Energy Agency (IEA) projects that the global vehicle fleet will grow from 1.3 billion today to 2.3 billion in 2040.

Lubricants are highly functionalized products that meet a multitude of requirements simultaneously. Today, they meet demanding technical-oriented specifications. In the future, non-technical criteria, like eco-toxicological properties and/or sustainability, will be added to their functionality on top of technical requirements. With sweeping environmental regulations from organizations such as the European Chemicals Agency (ECHA) and the US Environmental Protection Association (EPA), the growing concern for sustainability, and the advent of completely electric vehicles (EVs), the future of the lubricant industry for the next five to 50 years is sometimes called into question. This article will attempt to shed some light on this very uncertain future.

It would be remiss to discuss the future of lubricants for both automotive and industrial applications without mentioning the shift toward sustainability and using renewable resources (green chemistry) to derive new base oils, in total or in part. Around 1990, the first environmentally acceptable lubricants, or “EALs”, appeared in Europe; these new lubricants especially met eco-toxicological properties. Today, some of the important certifications for EALs are:

• European ecolabel as per EC/2018/1702 (3^rd revision);
• Second issuance of U.S. Vessel General Permit (VGP); and
• Biolubricants as per EN16807.

EALs with these certifications must have an accelerated, ultimate biodegradation (full mineralization) or short persistence in the environment when spilled. They have very limited toxicities for aquatic species like fish, daphnia, and algae, and they also contain a certain percentage of renewables. The issue of environmental friendliness is thus solved by legislations, test methods, and guidelines. “Biolubes” are available today for almost all classes of lubricants. They operate safely when they are used for their intended purpose.

A class of lubricants called “sustainable lubricants” have different attributes than the EALs. EALs focus on human and environmental toxicology when fluids enter the aquatic environment, whereas sustainable lubricants will consider:

• the carbon dioxide emissions throughout the product’s lifecycle; and
• the consumption of resources over the product’s lifetime, and the carbon dioxide emissions that are generated as a result.

The concept of sustainable lubrication has been and will continue to be very important as research shifts away from a heavy reliance on fossil fuels. On average, about 20 million barrels of petroleum were utilized every day last year in the United States alone, and this number will not get smaller unless there is a shift away from fossil fuels [1]. In addition, only about one percent of the petroleum that is extracted goes into the production of lubricants. World consumption is about 42 million tons of finished lubricants [2] annually, compared to about 4,500 million tons of oil [3]. This implies that as we focus on reducing the amount of petroleum that we use, there will be a lower volume of it available for the production of lubricants, so there needs to be a replacement for this loss in volume of petroleum. Sustainable lubricants derived from biomass and other renewable sources have shown to be very promising in addressing this issue and should remain a large focus in the near future.

Animal fats, vegetable oils, and other biomass feedstocks

With all these considerations in mind, much research has been focused on the development of bio-lubricants made from animal fats and vegetable oils. The pre-existing base oil alternatives comprise esters, polyalkylene glycols, and more recently bio-olefins, all based on renewables with a requested content of renewables of >25% or >50%. Esters are currently well known to be very useful for industrial applications that require excellent low-temperature properties. Esters that exhibit pour points of lower than -42°C have been synthesized and show viscosity indices that are near commercial lubricants, such as polyalphaolefins (PAOs) and polyolesters (POEs). Saturated, dimer fatty acid esters (DFAEs) are known for their thermal and oxidative stability. A group of researchers have synthesized DFAEs by combining dimer acid with different types of alcohols, and the approach does not use a solvent or any catalyst [4]. Different types of polyglycols have been known to have very high viscosity indices and lower pour points [5]. Reducing the amount of energy loss due to friction has been and will continue to be a focus regarding emissions reduction. A study done in 2017 used a very accurate high-load setup to compare the ability of two hydrocarbon-based lubricants versus a polyalkylene glycol-based lubricant to effectively lower friction. They found that the polyalkylene glycol-based lubricant led to 25% less friction than either of the two hydrocarbon lubricants [6].

Other promising feedstocks for base oils of bio-lubricants are microalgae and hydroxy-fatty acids [7]. The use of hydroxy fatty acids was confirmed to provide solid anti-wear and friction reduction properties by a study done in 2017 [8]. A different study done a year before this displayed the anti-friction and wear characteristics of bio-oils derived from microalgae [9]. This research toward developing more biodegradable and eco-friendly base oils for lubricants is very likely to take precedence very soon as environmental regulations become more stringent. The most important thing to know when considering this research focus is that lubricants can no longer be developed with the idea of purely fulfilling technical functions. Going forward, they will need to fulfill the standard technical requirements with the addition of eco-toxicological properties and/or sustainability criteria on top.

Another research area that has gained momentum in recent years and will likely continue is the investigation of additives containing nanomaterials. These have been known to increase the anti-wear and extreme pressure properties of various lubricants. They are also known to improve the properties of bio-lubricants and are considered environmentally friendly [9]. Some researchers have seen that graphene and carbon nanotubes used as additives can lower friction and wear coefficients in different types of lubricants [10,11].

How electric vehicles will change the game

A very important consideration in the direction of the lubricant market is the advent of electric vehicles (EVs), or the electrification of the powertrain/drivetrain. EVs require very specialized lubricants as opposed to the standard lubricants for internal combustion engine (ICE) vehicles. It has been predicted that the demand for automotive lubricants will not rise anymore due to the EV market. The largest demand for EVs are in both the European and Chinese markets, so the development of efficient EV lubricants will be of great value in the coming years in these areas. Large companies such as Royal Dutch Shell and TOTAL S.A. have already released their own lines of dedicated lubricants for EVs, so it seems that these companies and others that follow would be better positioned for the upcoming change in the global lubricants market [11,12].

An analysis done by McKinsey and Company [2] predicts much of the same thing. They say that looking ahead to 2035, the volume production of lubricants will decrease but the value can expand. This makes sense considering it has been posited that battery EVs need 50–70% less lubricants than ICE vehicles. This analysis also specifically predicts that in about five years, the global automotive lubricants demand will max out, after which the demand will decrease in the European and American markets but continue to grow in the Chinese market. As for the industrial lubricant sector, demand will continue to grow but will slow down after the next five years. Based on their analysis, McKinsey and Company predict that the value in the global lubricant market will increase by 44% in the next 15 years due to more advanced formulated synthetic lubricants and with the increased demand for industrial applications. This is consistent with the projected increase in stock of the vehicle market by the International Energy Agency (IEA) from 1.3 billion vehicles today to about 2.3 billion by 2040. However, McKinsey and Company point out that a 35% decrease in this projected value could occur due to battery technology becoming more affordable and continued tight regulations relating to the environment [12].

Looking even further ahead to the next 50 years is much harder to predict, but some scientists have given it a try based on past trends. Roland Larsson made a presentation at the 6th World Tribology Congress in 2017, where he predicted that lubricants will assuredly move toward renewable materials and tribo-modelling more into the future. The need for lubricants to be more renewable is very clear, and Larsson has proposed glycerol as a possible bio-lubricant. Glycerol is a by-product from biodiesel production and is widely available today. He also discusses the use of glycerol aqueous solutions to lower friction coefficient and possibly replace rapeseed oils [13]. The development of tribo-modelling, which optimizes tribology in the entire system, is very important, because developing viable lubricants that are sustainable can be challenging [14]. In conclusion, the development of lubricants made from renewables will take precedence for use in most automotive and industrial applications. Additionally, new market demands for EVs will require new dedicated lubricants that can provide much value to any companies that are willing to take on the research and development for them.

Raj Shah is a Director at Koehler Instrument Company in New York, where he has worked for the last 25 years. With a PhD in Chemical Engineering from Penn State University and a Fellow from the Chartered Management Institute, London, Raj has been an active member of AOCS for the last 2 decades. An Adjunct Professor at State University of New York, Stony Brook, Shah has been elected a Fellow by his peers at STLE, AIC, NLGI, INSTMC, CMI, IChem E, The Energy Institute, and The Royal Society of Chemistry. He is also a Chartered Scientist with the Science Council, a Chartered Petroleum Engineer with the Energy Institute, A Chartered Chemist with the Royal Society, and a Chartered Engineer with the Engineering council, UK. He has over 225 publications and is a co-editor of various books related to lubricants. He can be reached at rshah@koehlerinstrument.com. More information on Dr. Shah can be found at https://www.che.psu.edu/news-archive/2018/Alumni-Spotlight-Raj-Shah.aspx.

Mathias Woydt is managing director of MATRILUB (Materials-Tribology-Lubrication). He has more than 33 years of experience in R&D and has more than 325 publications and 50 plus priority patents filed. He is also the vice-president of the German Society for Tribology.

Nathan Aragon is part of a thriving internship program at Koehler instrument company, and a student of chemical engineering at Stony Brook University, New York, where Shah is the chair of the external advisory board of directors.

References

[1] https://www.eia.gov/tools/faqs/faq.php?id=33&t=6#:~:text=In%202019%2C%20the%20United%20States,billion%20barrels%20of%20petroleum%20products.

[2] A. Bau, et al. “Lubes growth opportunities remaindespite switch to electric vehicles.” McKinsey & Company 2018. https://www.mckinsey.com/industries/oil-and-gas/our-insights/lubes-growth-opportunities-remain-despite-switch-to-electric-vehicles.

[3] BP Statistical Review of World, 2019, 68th edition, https://www.bp.com/content/dam/bp/business-sites/en/global/corporate/pdfs/energy-economics/statistical-review/bp-stats-review-2019-full-report.pdf.

[4] Armylisas, A., et al., “Excellent properties of dimerfatty acid esters as biolubricant produced by catalyst-and solvent-free esterification,” Eur. J. Lipid Sci. Technol. 121:1900228, 2019.

[5] Salimon, J., et al., “Biolubricants: raw materials, chemical modifications, and environmental benefits,” Eur. J. Lipid Sci. Technol. 112: 519–530, 2010.

[6] Sander, D., et al., “Friction reduction tested for adownsized diesel engine with low-viscosity lubricants including a novel polyalkylene glycol,” Lubricants 5: 9,2017.

[7] Spaltmann, D., A. von Gablenz, and M. Woydt., “CO₂-neutral fuels and lubricants based on second generationoils such as jatropha,” J. ASTM Int. 7, paper ID JAI102549; https://doi.org/10.1520/JAI102549.

[8] Sturms, R., et al., “Lubricant properties of ω-1 hydroxybranched fatty acid-containing natural and syntheticlipids,” Tribology Letters 65: 99, 2017.

[9] Xu, Y., et al., “Influence of microalgal bio-oil on thelubrication properties of engine oil,” Oil & Gas Science and Technology – Rev. IFP Energies nouvelles 71: 29, 2016.

[10]. Uflyand, I., et al., “Metal-containing nanomaterialsas lubricant additives: state-of-the-art and futuredevelopment,” Friction 7: 93–116, 2019.

[11] Ali, I., et al., “Advances in carbon nanomaterials aslubricants modifiers,” J. Mol. Liq. 279: 251–266, 2019.

[12] A. Noel and K. Gilblom. “With electric cars,lubricants industry’s future is fuzzy,” Transport Topics, 2019. https://www.ttnews.com/articles/electric-cars-lubricants-industrys-future-fuzzy.

[13] Shi, Y., et al., “Boundary and elastohydrodynamiclubrication studies of glycerol aqueous solutions as greenlubricants,” Tribology Int. 69: 39–45, 2014.

[14] A. Stone, “2067: the future of lubrication,” F+L Magazine, 2020. https://www.fuelsandlubes.com/fli-article/2067-the-future-of-lubrication/.