The challenge: complying with more stringent emissions limits
Emissions limits are being tightened up in many regions worldwide. Complying with these is a challenge in asphalt production. At the same time, using the highest possible amount of recycling material is becoming ever more important in terms of saving resources.
While reclaimed asphalt can be added to the production process with reliable cold and hot recycling technologies, this does create higher emissions of total carbon (Ctot, volatile organic compounds (VOC)). When reclaimed asphalt is heated, part of the Ctot concentrations evaporate from the bitumen contained in the recycling material. These have a higher greenhouse potential than CO₂ and are hazardous to health in higher concentrations.
These emissions have to be reduced as much as possible with the objective of securing both the future of the plant site and the operating license for existing asphalt mixing plants. Owners of existing plants can achieve both with the REVOC innovation – which Benninghoven will be presenting at the BAUMA 2022 exhibition for the first time.
Solution: REVOC reduces Ctot emissions by up to 50 %
The REVOC system is a solution for reducing emissions from asphalt production by making the existing mixing plants more efficient and more environmentally friendly. The option of adding up to 60 % recycling material can reduce emissions to comply with legal limits. At the same time, the higher recycling content also increases the economic efficiency of existing plants.
Firstly, the REVOC system extracts the emissions directly where they are generated, primarily from the mixer in the asphalt mixing plant, where heated mineral, recycling material and bitumen come together to be mixed into fresh asphalt. The generated vapours have increased Ctot concentrations and are therefore moved to the REVOC system for thermal processing. This step uses the energy already generated for drying and heating the virgin mineral and is therefore extremely energy-efficient. Most importantly, however, the technology can reduce Ctot emissions by up to 50 %.