The Colas Group is investing in pioneering technology with building contractor SCERM to significantly reduce total carbon (CT/VOC) emissions.
The system was first presented to the public at bauma 2022 and was among the last three nominees for the bauma Innovation Award in the climate protection category. After the subsequent pilot project at WWA Westerwald Asphalt in Nentershausen (Germany) exceeded all customer expectations, the REVOC system from Benninghoven is now entering the next phase. In the town of Carros in the south of France, the existing Colas/SCERM plant is retrofitted with the “catalytic converter for asphalt mixing plants” as a Retrofit solution to update it to the latest state of the art.
The group of companies is active in over 50 countries and has around 3 000 production and recycling sites for the construction and maintenance of transport infrastructure, including in Carros near Nice in the south of France. The Société Carrossoise d'enrobage et de Matériaux (SCERM) has been running an Benninghoven asphalt mixing plant of type TBA since 2007.
Sustainability and climate protection have a high priority at Colas. The company is investing in the research and development of new technologies for driving decarbonisation and is striving to take on a pioneering role in the industry. The aim is to significantly reduce emissions in on all areas of the company. The special challenge of asphalt production lies in adhering to the limits for total carbon (TC/VOC) as adding recycled materials to the mixing process produces vapours with a high content of hazardous TC concentrations.
Plants like the TBA at SCERM, which is now 17 years old, had to be adapted to the new parameters. The added issue in Carros was that the surrounding structure had moved ever closer to the location of the plant over time, which made it even more urgent to reduce emissions with the latest technologies, and to therefore also secure the future of the site.
A densely built-up industrial zone has emerged where green fields used to be. The SCERM Benninghoven plant installed in 2007 required measures for reducing emissions in order to retain the operating license.
The potential options were reviewed together with Benninghoven. The aim was to implement a higher recycled content while complying with the strict emissions limits. Two alternatives emerged:
As the REVOC technology had already achieved excellent results in the pilot project at WWA Asphalt, Colas was quickly convinced by the advantages of the Retrofit solution. Another point in favour of the new system was that the very tight deadline could be met and the required retrofit measures, including replacing the dryer drum and the burner, were easy to integrate into the existing system. No major structural changes were required.
Asphalt mixing plant owners are facing a dilemma: On the one hand, they want and should use the highest possible amount of recycled materials, while on the other hand they have to adhere to the ever stricter mandated emissions limits. Adding reclaimed asphalt to the production process, however, results in a higher output of total carbon (TC). To reduce this while having a high recycled materials content, the REVOC system – also referred to as the “catalytic converter for asphalt mixing plant” – offers an efficient, economical and eco friendly solution. The exhaust gases are extracted directly at the point of origin and added to the system for thermal processing. This allows the total carbon emissions to be reduced by up to 50 % without compromising on adding recycled materials.
The patented technology supplements existing cold and hot recycling systems in asphalt mixing plants and reduces total carbon emissions (TC) with up to 50 % recycling material added. Specified limits are not exceeded. In Germany, for example, the level remains below the maximum specified by the TA-Luft regulation. This allows the plant owner to add up to 60 % recycled materials while adhering to the emissions limits.