Image Credit: David Tadevosian/Shutterstock.com
As technology advances and there is a greater need to increase the energy efficiency of machines, there is also a need for improved lubricants. Typically, lubricants have been made of oil and additives. in the case of grease, a thickener would be added. However, traditionally used petroleum-based lubricants are harmful to the environment. Lubricants with higher biodegradability are sought after, as more organizations face increasing pressure to be sustainable.
Why are Lubricants Needed?
Lubricants are vital for equipment functioning. They act as a microfilm layer between moving parts, help to protect equipment, and reduce damage and durability over time. Lubricating oil reduces friction, overheating, scuffing, rubbing, and corrosion due to its special properties. It is made up of a blend of base oil (over 85%) and additives which improve the overall quality of the substance.
Lubricating oils containing refined additives of petroleum origin have been used in outdoor machinery such as saws usually operated outdoors in forestry, where the equipment is in close contact with outdoor greenery. They are also used in agriculture for harvesters, earth-moving equipment, and more.
Oil’s Environmental Problem
When operating, the oil is directly emitted into the surroundings, causing negative impacts on the environment and human health. It has been reported that over 10 million tons of mineral lubricants and hydraulic fluids pollute the environment each year. In Europe, various industries consume an average of 5 million tons of lubricant, of which 40% directly pollutes the natural environment.
Demand for More Sustainable Oils
Biodegradable oils have increased in popularity in recent years, but even these oils can have up to 50% of a petroleum oil base. Critics have called to reduce the petroleum component further to lessen toxicity and harmful effects.
Researchers published a study in Environmental Research and Public Health outlining the impact of petroleum oil lubricants on soils, groundwater, vegetation, wildlife, and human health. Their review suggested that lubricating oils should only contain biodegradable ingredients to avoid negative impacts on the environment. Complete biodegradability should be confirmed through testing. Therefore, widespread control procedures and studies are needed.
Sustainable Alternatives to Lubricants
In some ways, the lubricants industry has long been intertwined with the petroleum business, tainted with a similarly environmentally damaging reputation. There are now more alternatives to petroleum oil, with a range of natural or synthetic base oils available.
Additives provide extra benefits such as friction reduction, corrosion, and temperature control. Advanced production technologies offer more sustainable solutions by using eco-friendly refining additives as an alternative to petroleum-based products.
When formulated from advanced biobased materials, lubricants can become even more environmentally friendly, being biodegradable, low toxicity, and less likely to bioaccumulate (where substances gradually accumulate).
The sustainable options are also known as Environmentally Acceptable Lubricants - a term popularized in the global marine market by the Vickers Oil company who has offered these products since 2002. These substances are often made from low molecular weight polyalphaolefin, polyalkylene glycol, synthetic esters, and vegetable oils. Reportedly, ester-based oils are the most common environmentally accepted lubricant in the market, due to their non-toxicity and effective biodegradation.
The Economy of Sustainable Oils
Crude oil is a well-known non-renewable natural resource, sourced from petroleum oil which took millions of years to form in the ground. By contrast, renewable products are typically grown, harvested, and turned into products within a relatively short time.
Most oils taken directly from animal and vegetable sources do not yield stable lubricants. It is this instability that makes them highly biodegradable, an environmental advantage, but has not been an economic advantage. Renewable oils such as these have been made and improved since the 1980s through genetic modifications and chemical processing. Some were made from vegetable oils but oxidized quickly and were more expensive, making them less economically viable for mass consumerism.
Lubricating oils with a base oil and vegetable-based additives appeared on the market in Europe in the mid-80s. These products have high biodegradability compared to other types of base oils, with biodegradability levels ranging from 70-100%, which are now commonly used in European forestry.
The Future of Eco-Friendly Lubricants
There is still a growing need for more efficient, sustainable lubricants to be brought to market, particularly as governments are putting more pressure on companies to use these greener lubricants.
There are expectations for these high-performance substances to be efficient and less environmentally damaging when emitted into the surrounding environment.
Many regulators are more concerned about lubricants being environmentally friendly than optimal in performance as companies pursue greener goals. The growing interest in the impact of lubricating oils on the environment and health motivates research centers and industries to innovate for fully biodegradable, lubricating oils made up of natural ingredients.
References and Further Reading
Can lubricants be green [Online] Biomass Magazine. Available at: http://www.biomassmagazine.com/articles/17390/can-lubricants-be-green (Accessed 22 March 2021)
Luther R. Lubricants in the Environment. In: Mang T, Dresel W, editors. Lubr. Lubr. 3rd ed., Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA; 2017, p. 153–236. https://doi.org/10.1002/9783527610341.ch7
Nowak P, Kucharska K, Kamiński M. Ecological and Health Effects of Lubricant Oils Emitted into the Environment. Int J Environ Res Public Health. 2019;16(16):3002. Published 2019 Aug 20. https://dx.doi.org/10.3390%2Fijerph16163002
Shi Y, Minami I, Grahn M, Björling M, Larsson R. Boundary and elastohydrodynamic lubrication studies of glycerol aqueous solutions as green lubricants. Tribol Int 2014;69:39–45. https://doi.org/10.1016/j.triboint.2013.08.013