Dieffenbacher and Tomra showcase technology for “fibreboard-to-fibreboard” recycling

EcoReFibre meeting and live demonstration at Dieffenbacher’s headquarters in Eppingen, Germany (Image: Dieffenbacher)

In May 2022, Dieffenbacher and 19 organisations from seven countries joined forces in the EcoReFibre research project, which has €12m in funding from the EU.

The project aims to recycle fibreboards at the end of their lifecycle and use the recycled wood fibres to produce new fibreboard.

After almost two years of intensive research, the consortium met at Dieffenbacher in Eppingen and Tomra in Mülheim-Kärlich on 23-24 Apr 2024. The purpose of the on-site meetings was to demonstrate and discuss important interim results of the research project.

Day 1: Dieffenbacher

Participants of the EcoReFibre meeting inspect the fines for the surface layer in particleboard production, which were produced with the single-shaft shredder, ClassiSizer and oscillating screen (Image: Dieffenbacher)

After a welcome from Dieffenbacher CEO Christian Dieffenbacher, the first day’s around 40 participants toured the factory at the company’s headquarters in Eppingen. The tour ended in the Dieffenbacher Technical Center, the company’s newly modernised and expanded in-house test laboratory and research centre.

“We have added a second steel construction level to our Technical Center, creating 10% more space. Control cabinets and auxiliary equipment now sit here without disturbing the testing processes on the machines,” reported Axel Ganster, team leader wood technology at Dieffenbacher.

“Along with modernising the existing machines such as the ClassiSizer, oscillating screen and exhaust system, we have added a single-shaft shredder, a roller screen, mobile conveyor technology and a central data collection system. Overall, our Technical Center now offers more testing options with a wide range of materials.”

Fibreboard recycling was next on the agenda. During the demonstration, fibreboard material was shredded to chip size in the single-shaft shredder designed by Dieffenbacher. The chips were then fed into a Dieffenbacher ClassiSizer.

“The ClassiSizer reduces the fibreboard material to the desired particle size,” explained Jean-Christophe Zimmermann, Head of Sales of Dieffenbacher’s Recycling Business Unit. “The material is resized by the high kinetic energy of the installed impact rotor and by the interaction of the individual particles with each other. After final screening on a Dieffenbacher oscillating screen, the fines produced can be used for the surface layer in particleboard production.”

The second part of the demonstration at Dieffenbacher was dedicated to fibreboard-to-fibreboard recycling, which is to say, the production of new fibreboard from recycled fiberboard material.

Using a Dieffenbacher ClassiScreen, the waste wood provided by EcoReFibre project partner Veolia was separated into fines, chip-size and oversized fractions.

In the same step, films, textiles and other lightweight materials such as paper were removed from the waste wood. “In a real-life application in a recycling plant, the oversized material would be re-shredded and fed back into the process. The fines would be cleaned and used for particleboard production,” explained Dieffenbacher technologist Jonas Réssy. “The chip-size material from the demonstration was made available to our partner Tomra for the next day’s demonstration.”

Day 2: Tomra and Dieffenbacher

On the agenda were three different live demonstrations on two sorting systems: Tomra’s x-ray solution X-TRACT and its latest deep learning system AUTOSORT with GAINnext (Image: Tomra)

In Mülheim-Kärlich, the second day’s event focused on sorting the recycled wood by type.

“The fibreboard fraction obtained from sorting can be used directly for fibreboard-to-fibreboard recycling,” explained Réssy. “The solid wood fraction can also be used as a substitute for fresh wood in fiberboard production. The remaining material not assigned to either of the two fractions can be used for particleboard production. We integrate the Tomra machines into our Dieffenbacher plant concept so that trouble-free sorting is possible on an industrial scale.”

This was followed by the actual sorting process. Tomra specialists conducted further tests on the AUTOSORT machine with its deep learning add-on GAINnext, whose technology is the company’s latest artificial intelligence innovation and is capable of solving complex sorting tasks.

During the second EcoReFibre demonstration, the intelligent sorting system recovered unprocessed wood, referred to as wood A, from the mixed wood fraction collected by the X-TRACT. In the third and last step, GAINnext sorted wood fibres from the processed wood B. The result is a clean fibreboard fraction with a purity that the EcoReFibre project participants were very pleased with.

“Our intelligent GAINnext deep-learning technology reliably identifies different types of wood, for example, solid wood or fibreboard, based on shape, size or other visual characteristics. The result is a pure fibreboard fraction ready for recycling. I want to thank our partner Dieffenbacher for inviting us to contribute our innovations to this research project,” Dieffenbacher quoted from Jose Matas, segment director wood at Tomra.

“These two intensive days have enriched the EcoReFibre project with important findings and taken it a decisive step forward,” summarised Stergios Adamopoulos, professor in Wood Science and Technology at the Swedish University of Agricultural Sciences in Uppsala, the consortium leader of the research project.