Eco-friendly technology is a top priority!

When an asphalt mixing plant has been giving faithful service for more than 40 years, you can certainly consider it to have been a successful investment. But if this “antique“ of machine technology is broken up into parts and turned into a future-oriented Recycling Priority Plant (RPP) – a plant whose priority is the production of asphalt with an extremely high RAP material rate – the cost-effectiveness reaches a whole new level. And that is precisely what BENNINGHOVEN have recently brought about for their long-standing customer, Johann Joos Tief- und Straßenbauunternehmung GmbH & Co. KG.

New BA 4000 RPP mixing tower

The centrepiece of the new plant at Breisach is a BENNINGHOVEN mixing tower of type BA 4000 with a mixing capacity of 320t/h. A parallel drum in counterflow with a hot gas generator for the gentle, indirect heating of granulated RAP ensures a high level of environmental friendliness and maximum RAP material rates. This unique innovation enables RAP material rates of 90 + X% to be achieved – higher than with any other recycling system on the market. Presented at Bauma 2016 and elsewhere, the innovation takes account of stricter emissions limits, and specifically those set by the new German technical instructions on air quality control (TA-Luft).

Added value delivered

“Just replacing the steel wouldn‘t get us anywhere – after all, our plant was working perfectly,” said Andreas Ruf, Managing Director of Johann Joos Tief- und Straßenbauunternehmung. What he required was tangible added value. And that‘s what BENNINGHOVEN delivered – and how! The new technology will allow the largest road construction company in the Freiburg area to produce recycled asphalt to practically any formula in the future. In addition to the hot feed system comprising a parallel drum with hot gas generator, BENNINGHOVEN have also retrofitted a cold feed system: a multivariable feed hopper for an RAP material rate of up to 40%. Meanwhile, the preliminary batching units and other parts of the previous plant were retained.

"The importance of recycled materials is growing apace around the world. Equipped with RPP mixing towers and parallel drums with hot gas generators, our customers are excellently positioned for the future."
Ralf Port, Key Account Manager, Sales BENNINGHOVEN

RAP material rates of 90 + X%

The new BENNINGHOVEN mixing tower of type BA 4000 meets the highest requirements on modern asphalt production. This is attributed in part to an EVO JET 4 combination burner for oil and coal dust delivering 23.7MW, 6-fold screening, a hot bin section with a 170t capacity in seven bins and mixed material storage silos holding 420t. Other new components included a housing, a filler tower and a modern and user-friendly control system – the BENNINGHOVEN Control System BLS 3000.

BENNINGHOVEN parallel drum in counterflow with a hot gas generator

The unique BENNINGHOVEN innovation takes account of the fact that many markets are looking to achieve an RAP proportion of 90%. The challenge here is to bring the RAP material to the processing temperature of 160°C while keeping emission levels within the normal range and taking care not to burn the bitumen. To achieve even higher RAP material rates while minimizing the level of emissions, BENNINGHOVEN are going their own way: heating the RAP material in the counterflow, which results in higher material and lower exhaust gas temperatures. The process is based on the use of a hot gas generator: while with direct firing, the RAP material, with its bitumen content, would “burn“, the hot gas generator only heats it indirectly.