Retrofit solutions from BENNINGHOVEN

Working in partnership to renew old technology

Retrofit| Shoulder to shoulder with customers and users

Asphalt mixing plants can often easily reach a service life of twenty to thirty years – if not longer. Over this incredibly long period, a lot can change in the world – requirements for recipes and qualities of the mixtures, for example, and often also the official regulations operators have to comply with in order to obtain their operating licence. Benninghoven supports customers and users through all the challenges of modernisation – with its very own retrofit division.

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Retrofit from Benninghoven modernises plants from all manufacturers

Retrofit solutions for modernising existing asphalt mixing plants make sense for lots of reasons – and are often more beneficial than investing in new equipment. In densely populated regions, a retrofit is often almost the only option, as obtaining new approval from the local authority would be a long and uncertain process. When an existing plant is renovated, on the other hand, no new approval is required in many countries. Benninghoven is the partner for mixing plant owners in all retrofit projects – regardless of which manufacturer originally installed the existing plant. In the process, customers benefit from the expertise and fairness which characterize Benninghoven.

Parameters which can change the “working life” of an asphalt mixing plant

  • Customers demand new, higher-quality asphalts which require the plant to have specific feed options.
  • Legislators tighten up emissions standards.
  • The ratio of reclaimed asphalt added to the process is increased, reducing raw material costs – but only for plant owners with the appropriate technology.
  • Dust and noise protection regulations (Germany’s “TA-Luft” and “TA-Lärm”, for example) required to retain an operating licence are made stricter – often because residential areas expand right up to the asphalt mixing plant which used to be in an isolated position.
  • Alternative fuels are required for the mixing plant burner.

Thomas Schnabel, Technical Director of the asphalt mixing plant of Guggenberger GmbH, is very enthusiastic about the individual retrofit solutions from Benninghoven.

Complete retrofit solution from a single source

From design and technical implementation to installation on site: The Benninghoven experts from the Wirtgen Group subsidiaries support the retrofit process all the way from the initial contact to final acceptance. They also establish the direct contact to the main Benninghoven factory. This is particularly important for plant owners because no two mixing plants are alike. Many solutions have to be adapted individually or even worked out from scratch to make the plant future-proof.

Seven good reasons for a Benninghoven retrofit

  • 1| State of the art:bringing the asphalt mixing plant up to the current state of the art
  • 2 | Protecting existing assets:ensuring that the site retains its operating licence
  • 3 | Sustainability and economic efficiency:replacing components and integrating recycling technologies pays off.
  • 4 | Optimisation and efficiency:modern control technology from Benninghoven improves plant performance.
  • 5 | Win-win:updating the plant can also be used as an opportunity to meet individual requirements - standard solutions have already been developed from customer ideas.
  • 6 | Improvements instead of repairs:the recommendation from Benninghoven experts will leave plants in a better state after the retrofit than before.
  • 7 | Any manufacturer:Benninghoven retrofit solutions are also possible for plants from other manufacturers.

Case study: Renovation of a BA 4000 mixing plant for Guggenberger GmbH in Mintraching

Individual customer solutions – as turnkey projects

The desire for more asphaltic mixture per hour was the main driver behind the current retrofit project. The focus was on higher performance and efficiency of the plant. Among other things, this included replacing the dryer drum and the burner. It soon became clear that a standard drum would not fit. Markus Bühl took this challenge back with him to the main Benninghoven factory to develop a solution together with the technical office.

Technical development since 2007

“A retrofit from Benninghoven is practically a turnkey solution”

Markus Bühl, Area Sales Manager for Benninghoven products at the Wirtgen Group in Augsburg.

Current requirements for the retrofit project of Guggenberger GmbH

  • Replacing the dual-fuel burner for oil and coal dust with a larger triple-fuel burner, with gas as an additional fuel for more flexibility and less dependence on the energy market
  • Increasing the overall performance of the plant and thus the ability to also compete for supplying motorway construction sites with stone mastic and mastic asphalts. These asphalts are made without recycling materials – the old plant was limited in this regard.

To ensure that everything comes together perfectly at the end, the process is divided into three steps.

  • Step 1
    Development of a joint retrofit plan
  • Step 2
    Technical investigation and implementation at the main Benninghoven factory
  • Step 3
    Implementation of the new technology on site

Step 1: Development of a joint plan

Each Benninghoven retrofit project starts with a meeting at the site. A team from the Wirtgen Group subsidiary which looks after the customer visits the customer with established Benninghoven experts. The existing plant is recorded and all requested changes are set out in writing. The Benninghoven planning manuals are a useful tool for this process. Photos of the plant and of the components to be replaced are also taken at this initial meeting.

Three questions for Markus Bühl

Mr Bühl, what do you do when you receive an enquiry for a retrofit project?
During the initial contact with the plant owner, I make an appointment for a meeting on site. Even though I am familiar with the plants of most customers, it is still important that I precisely understand the objectives to be achieved – and which technologies will improve performance in the long term.

How important is this personal exchange of information?
From my point of view, it is very important, there is no question about that. It is incredibly important to get to know and understand one another. This is the only way to achieve perfect results. As experts in the field, we also have an obligation to look beyond the obvious and to not just doggedly replace components like for like.

What role do plant personnel play in this process?
... they are always involved. It is not just the opinion of the boss which matters, but also that of the whole team. The team have to operate the plant and often bring good ideas to the table. What is more, when the new components are being fitted, these individuals frequently form part of the assembly team.

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Step 2: Technical investigation and implementation at Benninghoven

After the meeting at the plant site in Mintraching, the Wirtgen Group team discussed the requirements of Guggenberger GmbH at the main Benninghoven factory. For developing the optimum solution, Benninghoven uses swarm intelligence – specifically the know-how of the entire technical office paired with the experience of the installers on site. The Benninghoven technical office is very experienced in getting more performance out of old technology and above all also in adapting existing technical components to suit new ones. Once the design process is complete, the engineers prepare technical specifications and layout drawings.

“There were a whole range of requirements for this plant where standard solutions were not practical. But we are used to that from retrofit projects and we are able to implement these orders in a way that is economically viable for the customer as well. We look at the old components on site; these tell us what we need to take into account and what needs improving.”

Jörg Genetsch, expert for drying and dust collection systems at the Benninghoven technical office

Presentation and agreement with the customer team

The Wirtgen Group team presents this complete technical solution to the customer and discusses it with them until the project is approved. “Right back at the project planning stage, it was clear that the Benninghoven professionals know what they are talking about. Their expertise is considerable, so we felt we were getting good advice and were in good hands right from the start,” says Karl Weiss, mixing foreman at the Guggenberger GmbH asphalt mixing plant in Mintraching.

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Teamwork: Low-loaders transport the new dryer drum to its final position. The Guggenberger crew and the Benninghoven installers make a perfect team during this process.

Experience the precision teamwork in the video:

Step 3: Implementation of the new technology on site

Once the retrofit plan and all the new components have been approved, the components are manufactured at the main Benninghoven factory and transported to the job site. The customer’s plant personnel and the Benninghoven service engineers often form a team, as was the case on the Mintraching retrofit project. “And it works so well,” says Thorsten Neidhöfer, one of the Benninghoven installers on site.

Modern Benninghoven technology was integrated in the existing asphalt mixing plant, allowing for economical and environmentally friendly operation of the plant for many years. The heart of this plant are the burner and the dryer drum. With oil, liquid gas and coal dust, the new EVO JET 3 burner can now burn three fuels instead of two, which will make Guggenberger more independent of fluctuating energy costs in future. A new coal dust dosing system has been fitted for this fuel; its overhauled design will bring key benefits for Guggenberger in terms of functionality, safety and fuel consumption. What is more, the burner is designed for higher capacities and thus contributes to increasing the plant overall performance. The drying capacity increases significantly, especially for the production of mixtures such as stone mastic and mastic asphalts which are made entirely from virgin mineral – specifically, the output increases from 140 t/h to 190 t/h.

The following were integrated in the Guggenberger GmbH asphalt mixing plant:

  • A new, precision-fit frequency-controlled dryer drum. The existing foundations were reused.
  • Triple-fuel burners of type EVO JET 3 for burning oil, coal dust and gas. Its frequency-controlled burner output is 18.9 MW.
  • Recycling recipe generator to adapt the quantity of recycling material feed (cold and hot) during operation.
  • New coal dust dosing system with substantially improved control range increases efficiency. Learn more at

Three questions for Karl Weiss, mixing foreman at Guggenberger GmbH in Mintraching

Mr Weiss, what were the main reasons for giving your plant a substantial overhaul?
The desire for better plant performance was clearly the main driver. Specifically, we wanted to significantly increase the hourly output of binder and wearing course mixture. To achieve this, the drum and the burner for the virgin mineral had to be dimensioned for a higher output.

What were your reasons for deciding to collaborate with Benninghoven?
Our plant comes from Benninghoven and we are happy with the plant – but we also work well together, so it seemed obvious to approach Benninghoven to start with. The burner, in particular, is a fantastic device. If it ever needs replacing, Benninghoven would always be our first port of call. Our new burner can even run on three fuels, which makes us much more flexible.

Hindsight is a wonderful thing, as we all know. How did you find the partnership? And how do you rate the economic viability of your investment?
The collaboration was great. We complemented one another perfectly in both the planning and installation of the new components. Everything ran smoothly. We divided the tasks between us. So there were jobs we did ourselves, while the Benninghoven team dealt with others. Here too, each of us was always prepared to help the other side out. As far as economic viability is concerned, we can mix more at a lower fuel cost and we start earlier and finish earlier. That is really noticeable: We easily save half an hour’s working time every day.

Individual customer solutions:
Customized retrofit components are manufactured at the main Benninghoven factory.