“With our project, we have demonstrated that the large quantities of balsa wood used in wind-power rotor blades can be further utilized. This creates a vast potential for, amongst others, the recycling industry,” explains Peter Meinlschmidt, Project Leader at the Fraunhofer WKI. The innovative aspect of the approach lies in the fact that the usable sections containing the balsa wood are separated during dismantling of the rotor blade at its original location. This enables the separate processing and high-quality recycling of the materials.

On the Fraunhofer WKI stand, the researchers will be presenting a section of a wind-turbine rotor blade as well as the new products obtained from it. The exhibits demonstrate the versatile possibilities for wind-turbine operators, recycling companies, WPC and insulation-material manufacturers, wood-based materials manufacturers and the packaging industry.

New insulation and building materials

One innovation being exhibited at LIGNA 2019 is ultra-lightweight wood-fiber insulation mats made from balsa wood, which have densities of below 20 kg/m³. Mats with such densities have not previously been available on the market. The reduced density is combined with significantly better insulation, which results in advantages over insulation materials made from polystyrene, XPS or EPS. The wood-fiber insulation mats can be utilized in construction as between-rafter insulation and as solid insulation boards.

A further new product is extruded floorboards made from wood polymer composites (WPC) which have, up until now, not been produced from balsa wood. Due to the balsa wood, the floorboards are not only lighter but also stronger than the currently available standard WPC decking boards. Moreover, a novel wood foam made from recycled balsa wood will also be exhibited on the Fraunhofer WKI stand.

Solution possibilities for the disposal problem

“One advantage of the new recycling procedure is that rotor blades are no longer incinerated - during which valuable raw materials are lost in large quantities - but are instead exploited as a ‘material source’ for new products,” explains Project Leader Peter Meinlschmidt. The thermal utilization of rotor blades to date has also been difficult as, due to their size and mass, the fiber-reinforced plastics cause problems during combustion. “With our recycling approach, we offer solution possibilities for the disposal problem and simultaneously demonstrate innovative utilization opportunities for the recovered balsa wood,” summarizes Project Leader Mr. Meinlschmidt.

The project is being funded by the German Federal Ministry of Education and Research via its project sponsor, the Projektträger Jülich (PtJ).

Background: Fraunhofer WKI

Sustainability through the utilization of renewable raw materials has formed the focus at the Fraunhofer WKI for more than 70 years. The institute, with locations in Braunschweig, Hanover and Wolfsburg, specializes in process engineering, natural-fiber composites, wood and emission protection, quality assurance of wood products, material and product testing, recycling procedures and the utilization of organic building materials and wood in construction. Virtually all the procedures and materials resulting from the research activities are applied industrially.