Published 2018-11-22

This post is also available in Swedish

Hydraulic fluid with global potential

Petroleum-based hydraulic fluids are a threat to the environment and climate alike. A fossil-free type has been developed in the Mistra Innovation programme, and the plan is to launch a product within about a year. Its environmental potential is great, not only in Sweden, but also globally.

Hydraulics are used to drive a numerous industrial machines and processes, such as forestry machinery, mining drills and turbines in hydropower production. However, hydraulic fluids are still largely petroleum-based, and leaks are common. In Sweden alone, forestry machines are estimated to release around 4,000 tonnes of oil a year into the natural environment.

‘The hydraulic oil that leaks out causes direct contamination of lakes and land. The hydraulic oil left in the machine leads to other problems, since it’s destroyed and burned, which releases carbon dioxide into the atmosphere instead,’ says Professor Roland Larsson, Luleå University of Technology.

In recent years, Mistra Innovation has been running a project to develop a new fossil-free hydraulic fluid. Sustainalube AB, a start-up company in Luleå, is working with researchers at Luleå University of Technology and several Swedish companies. The project leader is Yijun Shi, who works with Larsson at Luleå University of Technology and is also Technology Director at Sustainalube AB.

The concept is based on optimising a hydraulic fluid based on glycerol and water. Glycerol, a residual product from biodiesel production, has a low environmental impact. Today it is used in soap and hand cream, for example, and also approved as a food additive.

So far, the project findings, both in the laboratory and from full-scale tests, have been encouraging. The fluid has been used in, for example, an overhead crane at Boliden’s Rönnskär smelting plant, with good results.

‘We’ve developed a product with several good properties, including lower friction than today’s hydraulic oils. It seems possible to cut the friction losses by 10 to 50 per cent,’ Larsson says.

Further optimisation and in-depth operational tests are under way in the project, which ends in 2019. Sustainalube will, for example, test the hydraulic fluid in a forestry machine in northern Sweden. If all goes to plan, a product will be launched next year, primarily on the Swedish market but, in the long term, also in Europe and the rest of the world.

Climate change makes it essential to stop using oil-based hydraulic fluids, but this will take time, Larsson believes.

‘This is a very conservative sector that’s backed by the oil industry. But in the long run the market will be gigantic. Then we’ll be in a very strong position with patents and a finished product.’

Mistra Innovation is an initiative in which 24 small and medium-sized companies, in collaboration with higher education institutions, have been running research and development projects of high environmental potential. The programme ends in 2019, and Lars Frenning, Programme Director of Mistra Innovation, is very pleased.

‘So far, we’ve had a wonderful outcome. Sixteen projects have been completed, 14 of them have resulted in finished products and 10 of these have begun to be marketed and sold.’

Text: Henrik Lundström