At construction company SCERM, Colas Group has invested in advanced technology to achieve significant reductions in total carbon emissions (TC/VOC).
This world first was introduced to the public at bauma 2022 and was one of the final three nominees for the bauma Innovation Award in the Climate Protection category. With the subsequent pilot project at WWA Westerwald Asphalt in Nentershausen managing to exceed all customer expectations, the REVOC system from Benninghoven has now entered the next phase. In Carros in southern France, the existing plant operated by Colas/SCERM will be equipped with a catalytic converter for asphalt mixing plants as a Retrofit solution, turning it into a state-of-the-art facility.
Colas Group is active in 50 countries worldwide, with operations including around 3,000 manufacturing and recycling facilities for construction and transport infrastructure maintenance – as in Carros in the south of France, not far from Nice. Here, Société Carrossoise d'enrobage et de Matériaux (SCERM) has operated a Benninghoven asphalt mixing plant of the TBA type since 2007.
As a company, Colas focuses strongly on sustainability and climate change mitigation, and has invested in the research and development of new technologies with the aim of accelerating its decarbonization and assuming a pioneering role in its industry. Colas has plans to cut emissions significantly throughout the Group by 2030. The company’s asphalt production division faces the particular challenge of meeting regulatory limits for total carbon emissions (TC/VOC): this is because the addition of recycled material into the mixing process creates vapors with high concentrations of harmful TC.
Facilities like SCERM’s TBA, which is now 17 years old, must be modified to comply with these new parameters. At the Carros plant, another factor was the development of the surrounding area, which has been steadily encroaching on the plant site: this has made the need to lower emissions by using the latest technologies even more urgent, to ensure that the facility can stay operational going forward.
The fields that used to encircle the site are now a heavily developed industrial zone. For SCERM’s Benninghoven plant, which dates back to 2007, measures to reduce emissions were urgently needed to avoid the plant’s operational permit being revoked.
Benninghoven was consulted to review the available options, with the aim of achieving high recycled material feed rates while complying with strict emission limits. Two alternatives were considered:
Since REVOC had already achieved outstanding results in the pilot project at WWA Asphalt, Colas was soon convinced of the benefits of the Retrofit solution. Another argument in favor of the new system was that the timing was now very tight and the retrofits needed – which included the replacement of the dryer drum and the burner – would be easy to integrate into the existing facility. No major structural changes were required.
Operators of asphalt mixing plants face a dilemma: while maximizing the proportion of recycled material is both desirable and advisable for environmental reasons, complying with the increasingly strict regulatory emission limits is unavoidable. However, the addition of reclaimed asphalt to the production process results in higher total carbon (TC) emissions. To reduce these emissions while simultaneously maintaining high feed rates for recycled material, the REVOC system – a catalytic converter for asphalt mixing plants – offers an efficient, cost-effective, and environmentally friendly solution. The exhaust gases are extracted directly at the point of generation and then routed to a thermal treatment system. This approach allows total carbon emissions to be reduced by up to 50% without having to compromise on rates for recycled material feed-in.
The patented technology supplements existing cold- and hot-feed recycling systems in asphalt mixing plants, and reduces total carbon emissions (TC) when feeding in recycled material by up to 50%. 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 operator to achieve recycled material feed-in rates of up to 60% while still meeting emission limits.