Extremely sustainable and efficient hot-gas generator
Plant owners who turn reclaimed asphalt into fresh asphaltic mixtures not only work sustainably, but can also save money thanks to the hot-gas generator. That is because the costs for the recycling material are substantially lower compared to virgin mineral from a quarry. The main reason for this is that the reclaimed material already contains bitumen. The price of the most expensive ingredient for asphalt production has increased significantly in recent years and is also subject to strong fluctuations. As there are more roads being refurbished than new roads being built, many regions are increasingly focusing on re-using reclaimed asphalt.
With a maximum possible recycling content of 100 %, the hot-gas generator is a pioneering solution, also with respect to economic efficiency.
Hot-gas generator defines the state of the art in recycling technology
High recycling content along with low emissions can only be achieved using the principle of counterflow action in combination with a hot-gas generator. This process generates only low levels of Ctot because the recycling material is heated to only 160 °C. In the case of natural rock asphalt – in contrast to recycling material – harmful substances already evaporate at temperatures below 160 °C. The hot-gas generator, however, can reduce these substances to a level where they are no longer an issue.
For the counterflow action, the burner fires into the hot-gas generator and intensively heats the surrounding air in the recycling drum. This hot air then heats the recycling material in the downstream recycling drum in an indirect and gentle process. This already brings the recycling material up to the final temperature. “So we add only hot gas to the material in the recycling drum, because the recycling material with adhering bitumen would ‘burn’ upon direct flame contact,” Steven Mac Nelly, Head of Development & Engineering at Benninghoven, explains the principle.