An Advanced Retrofit with a Futureproof Solution




With the successful partial renovation of a mixing plant in Braunfels, in Germany’s Taunus region, Benninghoven has once again demonstrated the flexibility of its retrofit solutions.

Despite the cramped conditions on site, 2 key parts – the mixing tower and the drying line – of the original asphalt mixing plant had to be replaced. However, the recycling plant together with the other units were to be kept as-is. This created plenty of challenges for planning, logistics, and assembly, which all had to be discussed with the customer beforehand.

The project aimed to achieve a much-needed increase in productivity at the plant. The mixing tower in particular was becoming increasingly problematic as a bottleneck. The laying fleet owned by Wilhelm Jost GmbH & Co. KG installs 80% of the asphaltic mixture itself, with the rest being sold to other contractors. Although the original plant was from a competitor, the road-building company decided to go with the retrofit solution from Benninghoven. Bernd Jost, CEO of Wilhelm Jost GmbH & Co. Kg was already very familiar with the quality offered by products and projects from Benninghoven. An EVO JET burner installed as a retrofit 15 years ago was still running reliably today, and cold/hot recycling feed systems had been integrated, bitumen tanks added, and the plant control system has also been swapped out in favor of a Benninghoven BLS 3000.

“This is why we had every confidence that our partner would also meet all of our expectations in full for this new project,” explained Mr. Jost.

Mixing capacity increased from 200 t/h to 320 t/h
The drying line needed to be replaced along with the mixing tower. Although the capacity of the old hot bin section for storing heated virgin mineral was only 80 t, the new Benninghoven system based on the TBA 4000 series has increased this to 130 t in 7 bins. Screening plant capacity is 290 t/h and loading silo capacity has now been doubled to 440 t. Up to 8 separate types of asphaltic mixture can now be stockpiled here, with 2 chambers also offering long-term storage.

The new mixing tower is also based on a TBA 4000 plant. Thanks to a 4-t mixer, up to 320 t/h of asphaltic mixture can now be produced, along with a wide range of recipes. The existing Benninghoven parallel drum hot feed system means a recycling rate of up to 70% is also possible. while the cold recycling system mixer feed supports rates as high as 30%.

The necessary components were quickly defined and inspected during a customer visit to Benninghoven’s main factory in Wittlich, which also concluded with a discussion of open issues for the project. This was required because planning was made more difficult by the need to retain existing plant components and areas. Above all, the extreme lack of space had to be accounted for, because these conditions could not be changed. Benninghoven also completed the structural analysis for the mixing plant and loading silo steelwork, including the calculation of supporting loads for the on-site concrete foundations and the required steel sections.

Logistics and assembly work for the recycling plant, with its parallel drum some 30 m high, was also another a major challenge, as was the integration of other components such as the cold feed unit, the EVO JET burner, the coal dust silo, bitumen tanks and piping, and the retention of the control cabinet plus control cabinet container. All in all, the circumstances on site required a lot of ingenious solutions that were successfully put into practice by the experienced plant teams.

For Kai Phillips, project manager at Wilhelm Jost GmbH & Co. Kg, it was especially important to have a “partner who you can trust 100%”, especially on a major investment project like this one. Work on dismantling the old components started in winter. Six months later, and with all of the tests completed as part of commissioning, the newly renovated plant was able to load up the first asphaltic mixture truck from the road-building company and send it off to the next laying job.

Source: Wirtgen Group

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