REVOC system proves successful

Drone view of the Benninghoven plant in Nentershausen with the new REVOC system

Expectations exceeded

At WWA Westerwald Asphalt, the TC emissions can be reduced by more than 50 % thanks to the new REVOC system.

As part of a pilot project, the innovative REVOC system from Benninghoven was installed for the existing asphalt mixing plant of WWA Westerwald Asphalt GmbH & Co. KG in Nentershausen. After the official world debut at bauma 2022, this has allowed the “catalytic converter for asphalt mixing plants” to also successfully prove itself in practical application – and it has exceeded the customer’s expectations.

High-quality asphalt mixture for road and path construction

The Benninghoven type TBA plant, manufactured in 2007, is located on the site of a basalt quarry and produces between 80,000 and 100,000 t of high-quality asphalt mixture for road and path construction every year. Benninghoven and WWA Westerwald have always had a good and trusting relationship. In 2021, the customer was therefore quickly ready to accept the proposal of taking on a pioneering role and retrofitting the new REVOC system.

“We chose the REVOC system because it allows us to reliably comply with the TC limits even with a high content of recycled material.”

Peter Bach, Managing Director of WWA Westerwald Asphalt

Eco-friendly and preserves resources

Thanks to the patented, pioneering technology, Westerwald Asphalt can now increase the maximum content of recycled materials from previously 30 – 40 % to 50 % while reducing total carbon (TC) emissions by more than 50 %. In the interview, Managing Director Peter Bach talks about the first practical experiences with the new system and what the installation means for securing the future of his plant.

High content of reclaimed asphalt and low emissions – it is possible!

Sustainable asphalt production is determined by two aspects: On the one hand, the content of recycled materials has to be increased in order to save resources and make practical use of old materials. As the content of reclaimed asphalt increases, less fresh bitumen is needed, which also works to lower the carbon footprint. On the other hand, the strict TC limits of < 50 mg/m³ specified by the German TA-Luft regulation must be met in order to protect the climate.

Previously, reclaimed asphalt could easily be added to the production process by means of cold +or hot recycling technologies. This, however, results in higher total carbon emissions (Ctot, volatile organic compounds – VOC). When reclaimed asphalt is heated, part of the Ctot concentration volatilises from the bitumen in the recycling material. TC has a greater greenhouse gas potential than CO₂ and is also hazardous to health at higher concentrations.

In the past, trying to reconcile a high content of reclaimed asphalt with the need to reduce the environmental impact was virtually impossible. With to the powerful REVOC system, these two aspects can now be consolidated: reducing TC emissions by up to 50 % while achieving a higher recycling content of up to 60 %.

REVOC – eco-friendly and economical

The system works like a catalytic converter. The vapours generated in the mixer of the asphalt plant are extracted directly where they arise and transferred to the REVOC system for thermal processing. This can reduce TC emissions by up to 50 %, enabling the plant owner to increase the amount of reclaimed asphalt added without running the risk of exceeding the limits. At the same time, reduced use of the primary raw materials saves resources and costs. In addition to these economic and ecological aspects, use of the REVOC system is an investment in securing the future of the plant – also with respect to any additional future emissions restrictions.

Direct extraction

The REVOC system extracts waste gases directly where they arise.

Reduced TC emissions

The technology can reduce TC emissions by up to 50 %.

Customisation

The system was tailored specifically to the plant.

Emissions extraction in the REVOC system

Aerial view of the customised Nentershausen plant

Measurements confirm results

One year on from the first discussions, the REVOC system was installed in the plant at WWA and customised. Close support was provided from the outset – directly on site, over the phone or with remote service. This primarily included regular measuring of the emissions values and the associated fine adjustment of the plant. The result significantly exceeded the expected 50-% reduction in emissions and was repeatedly confirmed with external measurements. “Even if the upper emissions limits were to be reduced further, we are absolutely on the safe side,” explains Peter Bach, Managing Director of WWA Westerwald Asphalt.

“We are very satisfied.”

Peter Bach, Managing Director of WWA Westerwald Asphalt

Good perspectives for owners of older plants

Increased plant performance, high recycling content and reduced emissions: Existing plants equipped with the REVOC system as a Retrofit solution are also ready for the challenges of the future.

To the REVOC system