Retrofit solutions from Benninghoven

Partnerships for upgrading legacy technology

Retrofit| Working together with customers and users

Asphalt mixing plants can last 20 or 30 years – if not even longer. During such a long service life as this, a lot can change, including requirements in terms of mix formulation and quality, as well as the rules and regulations that operators must meet in order to stay licensed. Benninghoven aids and assists customers and users through all the challenges of modernization with its in-house Retrofit division.

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Benninghoven Retrofit for manufacturer-neutral modernization

Retrofit solutions to modernize existing asphalt mixing plants make sense for many reasons – and are often more beneficial than investing in a new plant. In densely populated areas, retrofitting may even be the only realistic solution, as obtaining a new operating permit would be a lengthy and uncertain process. In many countries, however, no new approval process needs to be completed when upgrading an existing plant. Benninghoven is the right partner for mixing plant operators on any retrofit project – regardless of which manufacturer originally installed the existing plant. Customers also benefit from the expertise and fairness for which Benninghoven is renowned.

Parameters that affect the “life expectancy” of an asphalt mixing plant

  • Clients are demanding new, higher-quality asphalts that mean plants have to provide specially adapted feed options.
  • Legally enforced emission standards are getting stricter.
  • While used asphalt recycling is becoming more common and depressing the costs of raw materials, operators need the right technology to benefit.
  • Dust and noise pollution controls (like TA-Luft/TA-Lärm in Germany), which have to be met to retain operating permits, are being tightened – often because residential areas are encroaching on formerly remote asphalt mixing plant sites.
  • There is a demand for wider use of alternative fuels to fire mixing plant burners.

Thomas Schnabel, Technical Manager at the Guggenberger asphalt mixing plant, is really impressed with Benninghoven’s custom retrofit solutions.

A complete, all-in-one retrofit solution

From the conceptual design to engineering and on-site implementation: Benninghoven experts at Wirtgen Group offices assist and support the retrofit process from initial contact through to final acceptance. The experts also provide a direct link to the Benninghoven main plant. This is especially valuable for mixing plant operators, because no two plants are alike. To make the plant design future-proof, many solutions have to be modified specially or even created from scratch.

Seven good reasons for choosing a Benninghoven retrofit

  • 1 | State of the art:Upgrade your asphalt mixing plant to the latest technical standards.
  • 2 | Asset protection:Act to ensure your site retains its operating permit.
  • 3 | Sustainability and cost-effectiveness:Replacing components and integrating recycling technology is an investment that pays its way.
  • 4 | Optimization and efficiency:Modern control technology from Benninghoven improves plant performance.
  • 5 | Win-win:A plant update can also be useful in meeting individual requirements – in fact, some production solutions have already been developed from customers’ ideas.
  • 6 | Improvements instead of just maintenance:Based on recommendations from Benninghoven experts, plants always benefit from retrofitting.
  • 7 | Manufacturer-neutral:Benninghoven Retrofit solutions can also be used on plants from other manufacturers.

Case study: Renovation of a BA 4000 mixing plant plus parallel drum operated by Guggenberger GmbH in Mintraching

Turnkey custom solutions designed and delivered

This current retrofit project started with a basic need to boost the hourly rate of asphaltic mixture output. So the focus of the project was on enhancing the plant’s performance and efficiency. This meant replacing the dryer drum and the burner, among other upgrades. It quickly became clear that a standard drum would not do the job. Markus Bühl took this challenge back to Benninghoven headquarters and worked with the Engineering department to develop a solution.

Technical developments from 2007

“A retrofit from Benninghoven is effectively a turnkey solution.”

Markus Bühl. Area Sales Manager for BENNINGHOVEN products at the Wirtgen Group office in Augsburg.

Current requirements for the retrofit project at Guggenberger GmbH

  • Replace the dual-fuel oil and coal dust burner with a larger triple-fuel burner that adds gas as an extra fuel, to deliver greater flexibility and independence from the energy market.
  • Improve overall plant performance, and so boost competitiveness by ensuring the company can also supply highway construction sites with stone mastic and mastic asphalt. These asphalts are produced without using recycled material – something the old plant could not deliver.

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

  • Step 1
    Development of a jointly agreed retrofit plan
  • Step 2
    Technical testing and engineering at the Benninghoven main factory
  • Step 3
    On-site implementation of the new technology

Step 1: Development of a jointly agreed plan

Every Benninghoven retrofit project starts with an on-site meeting. A key account management team from the Wirtgen Group office visited the customer along with certified Benninghoven experts. An inventory is recorded of the customer’s existing machinery pool, and all change requests are documented. Benninghoven has planning manuals which serve as useful tools at this stage. At this initial meeting, photos were also taken of the plant itself and the components that are going to be replaced.

Three questions for Markus Bühl

How do you respond when you get a request for a retrofit project?
After being contacted by the plant operator, I first arrange an on-site meeting. Even though I’m familiar with most customers’ plants, I have to understand exactly what they are aiming to achieve, and what technologies will boost their performance over the long term.

How important is this face-to-face meeting?
I definitely think it’s very important. It’s essential we get to know and understand each other. This is the only way to ensure that we achieve the right outcome. As technical experts, we also have a duty to always think outside the box and not just replace one component with another.

What role do plant personnel play here?
They are always involved. After all, it’s not just the boss’s opinion that counts; the views of the entire team need to be heard. They’re the ones that have to run the plant, and they often come up with good ideas. They also often work together with our staff as a combined team when installing new components.

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Step 2: Technical testing and engineering at Benninghoven

Following the site meeting at the Mintraching plant, the Wirtgen Group team discussed Guggenberger’s requirements back at Benninghoven headquarters. To develop an optimal solution, Benninghoven utilizes internal crowdsourcing: drawing on the know-how of the whole Engineering department paired with the experience of the on-site fitters. Not least because the Benninghoven Engineering team is experienced in getting more performance out of legacy technology – and especially at adapting existing technical components to new uses. Following on from the conceptual design, the engineers then draw up technical specs and layouts.

“This plant imposed a whole set of requirements on us for which off-the-shelf solutions weren’t much use. But that’s something we’re used to on retrofit projects, and can always complete these jobs in a cost-effective way for the customer. We also review the existing components on-site, and they tell us what to look out for and what needs improving.”

Jörg Genetsch, Drying and Dust Extraction Consultant in Benninghoven’s Engineering department.

Presentation and consultation with the customer’s team

The Wirtgen Group team presents its overall technical solution to the customer and negotiates this document until the project is approved. “Right from the project planning stage, it was obvious that Benninghoven knew exactly what they were talking about. They’re real professionals, with real-world expertise. So we were sure of being well advised and in good hands all the way,” comments Karl Weiß, Mixing Supervisor at Guggenberger’s asphalt mixing plant in Mintraching.

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Teamwork: Low loaders maneuver the new dryer drum into its final position. Another example of the perfect partnership between the Guggenberger crew and the Benninghoven fitters.

Check out the video to see this seasoned team in action:

Step 3: On-site implementation of the new technology

After the retrofit plan and all the new components have been approved, the components are manufactured at the Benninghoven main factory and transported to the site. Often, the customer’s plant personnel and the Benninghoven service technicians will work together as a single team. And that’s exactly what happened with the Mintraching retrofit project. “And it was a great success,” reports Thorsten Neidhöfer, one of the Benninghoven installers on site.

State-of-the-art Benninghoven technology was integrated into the existing asphalt mixing plant, giving it an economical and eco-friendly future for years to come. At the heart of the system are the burner and the dryer drum. The new EVO JET 3 burner now uses three fuels – oil, liquefied gas, and coal dust – instead of just the two as before. This makes Guggenberger less dependent on fluctuations in energy prices in the future. For the coal dust fuel, a new, redesigned dosing system was installed which will deliver key benefits to Guggenberger in terms of functionality, safety, and fuel consumption. The burner’s power rating has also been increased, which will help to enhance overall plant performance. For the production of mixes such as stone mastic and mastic asphalt in particular, which are made exclusively from virgin mineral, drying capacity has now increased significantly: from 140 t/h to 190 t/h.

The following were integrated into the Guggenberger asphalt mixing plant:

  • A new and custom-fit, frequency-controlled dryer drum. The existing foundations were also re-utilized here.
  • Triple-fuel EVO JET 3 burner, for use with oil, coal dust, and gas. The burner has a frequency-controlled output of 18.9 MW.
  • Recycling recipe generator to adjust the recycled material feed rate (cold and hot) during operation.
  • New coal dust dosing system with greatly increased control range, to improve cost-effectiveness. For further details, see

Three questions for Karl Weiß, Mixing Supervisor at the Guggenberger Mintraching plant

What were the key reasons for this comprehensive upgrade to your plant?
Improving plant performance was obviously our main concern here. In particular, we were look to significantly increase the amount of binder and wearing course mix we can produce per hour. To achieve that, the drum and the burner for virgin mineral had to be upgraded.

Why did you decide to bring in the Benninghoven team?
Well, our plant is a ‘Benninghoven’ and we’re very satisfied with it – plus they are always great to work with. So it made sense to at least approach Benninghoven first of all. The burner in particular is a top performer. When it needs replacing, Benninghoven will always be our first port of call. Our new burner can even be run on three types of fuel, which makes us much more flexible.

As we all know, we’re always wiser after the event. How did the partnership work for you? And how do you rate the cost-effectiveness of your investment?
Well, the cooperation was great. Our teams complemented each other perfectly in terms of planning and installing the new components. Everything went super-smoothly. We split the tasks between us. So there were some types of job we handled ourselves, while the Benninghoven team worked on the others. But we were always happy to help each other out when needed. In terms of cost-effectiveness: we can mix more at a lower fuel cost, and we can also start earlier and finish sooner. That really hits home: we’re easily saving half an hour’s worth of work every day.

Purpose-built solutions:
Benninghoven’s main factory produces made-to-measure retrofit components