At Oak Ridge National Laboratory (ORNL), which is part of the US Department of Energy, scientists have developed new additives for water turbine oil.
These will still be able to safeguard the environment while effectively protecting equipment from wear.
In some applications, lubricants inevitably seep into the environment, so nature-based solutions like the Shell Naturelle range of biodegradable lubricants are often used to avoid harming the environment. While these can still provide good performance, they need to avoid certain additives that could improve performance further.
ORNL scientists have therefore started looking at ionic liquids (ILs) as high-performance yet biodegradable and non-toxic additives for water turbine oil. These organic salts maintain stability at various temperatures, combine well with oil and reduce the friction between components.
The ORNL’s Biodiversity and Ecosystem Health group lead, Teresa Mathews, said that with lubricants, there were three primary areas of concern from an environmental perspective:
“They have to be highly performing. We don’t want them to be toxic to any aquatic organisms, and if there’s a spill, we don’t want the lubricants to be compounds that last in the environment. We want them to degrade very rapidly.”
The scientists designed, synthesised and tested the most promising ILs with a good combination of properties, namely phosphonium phosphate and ammonium phosphate. They then combined the ILs with base oils and compared it with a gear oil that was already commercially available. The ILs were found to reduce equipment wear tenfold and cut friction in half, which shows great promise for applications like tidal turbines, which are typically designed with a six-year service cycle.
