Why the choice of lubricant base oil matters?

Sustainability contributions of polyol ester based engineered fluids

Lubricants are used almost everywhere: in industries, in cars, trucks, trams and locomotives, in air conditioners, refrigerators and cooling systems. By choosing lubricants wisely, producers can reduce the environmental footprint of their product: saving energy and reducing emissions of greenhouse gases, reducing harm to the environment from leakage and decrease the use of virgin fossil raw materials.

Reduce greenhouse gas emissions

Let´s first think about climate change. To avoid and counteract serious changes in the climate, we need to limit energy consumption. The choice of lubricant can play a significant role to this end. Lubricants decrease friction and thus energy used in a system. By choosing more efficient and purpose-designed lubricants, considerable energy savings can be made. The potential savings by better lubricants and other means to decrease friction has in a recent review been estimated to no less than 9 percent of global energy consumption.1

Also, the raw material of the lubricant affects emission of greenhouse gases, and can be lowered by choosing lubricants where renewable sources have been used.

Leakage into nature

Secondly, there are many applications where it’s almost impossible to keep lubricants from leaking. It’s generally considered that somewhere between 20 and 40 percent of all used lubricants end up in nature. Therefore, the level of toxicity of a lubricant matters, how easily it degrades in nature and whether it accumulates in living organisms and ecosystems.

Unfortunately, the mineral oils used today as base in almost 90 percent of lubricants are often environmentally toxic and slow to degrade, with half-life times of several hundreds of days. Mineral oil alternatives, such as vegetable oils and synthetic esters on other hand, are easily biodegradable, with half-life time around 10-25 days. They are also usually less toxic, and have a weaker tendency to accumulate in nature.

Protecting marine ecosystems

For this reason, where risk is high for leakage into sensitive ecosystems, authorities and lawmakers support the use of environmentally accepted lubricants. In marine ecosystems for example, a leaked lubricant will not stay at the point of leakage, but spread around in seas, lakes or rivers. Many countries therefore demand or support the use of environmentally accepted lubricants in motors and other machinery on boats and vessels, in machinery and equipment in areas close to waterways, as well as in forests.

Human contact and safety

In situations where lubricants may easily come in contact with humans, synthetic lubricants pose far less of a danger than lubricants based on mineral oil. Here, synthetic esters should also be preferred for safety reasons – they can be designed to have a significantly higher flaming point than mineral oils, and thus pose less risk for fires.

Focusing on renewable sources

Thirdly, with an increasing world population and ambitions to reach similar standards of living worldwide, replacing virgin fossil materials will constitute an ever growing challenge. There is a need to find renewable and recycled sources for different materials, and also applies to lubricants. This means a shift from mineral oils to synthetic lubricants and brings with it the benefit of being able to design the fluid to fit special technical and other environmental requirements. For synthetic lubricants, it also means a shift away from virgin fossil raw materials. One way to achieve this is to gradually shift from virgin fossil to renewable or recycled raw materials.

Third party accreditation

There are several reasons for producers and users of lubricants to consider environmental aspects. Today, there are several systems of ecolabeling for environmentally acceptable lubricants (EAL) with the EU Ecolabel being the most generally accepted. It demands not only that the lubricant be minimally toxic as well as biodegradable but also unable to accumulate in nature. The lubricants should also be produced in ways that reduce carbon dioxide emissions and have a high percentage of renewable raw materials.

The case for synthetic lubricants and engineered fluids

The current market for synthetic lubricants is dominated by polyol ester base oils. These base oils - formed by fusing alcohols with two or more hydroxyl groups with organic (carboxylic) acids of different lengths and forms (branched/unbranched) – can be engineered in many different ways and with different characteristics. This gives the producers of polyol esters unique possibilities to tailor make base oils for lubricants that combine desired technical characteristics for performance with ecological demands on biodegradability, toxicity, bioaccumulation and manufacturing from renewable raw materials.

Perstorp is today the world’s leading provider of both poly-alcohols (polyols) and organic acids for polyol ester production. Its portfolio of Pro-Environmental products from renewable or recycled content are ready to be dropped into existing polyol ester formulations. Based on a traceable mass balance concept applying chemical and physical traceability, the Pro-Environment polyols and acids reduce the carbon footprint throughout the value chain and support sustainable sourcing of renewable and recycled raw materials.

Conclusion

To conclude, the choice of lubricant base oil matters for making products more environmentally friendly and sustainable. With polyol ester based lubricants, it is possible at the same time to save on energy and equipment by fine-tuning technical parameters of a lubricant, obtain compatibility, make them safe for ecosystems and to be produced in a more environmentally friendly way.



1 https://www.mdpi.com/2075-4442/9/2/21