Often trumpeted, seldom achieved, but realised at VW: a waste disposal centre has been built up within several years in Volkswagen Group’s commercial vehicle plant in Hanover, which successfully produces high-grade recycled materials in-house.

It is above all the Transporter (T5) medium-sized “people-mover”, but also the LT (Large Transporter) range and the Amarok pick-up truck that are made by VW Group in Hanover. In addition, components such as heat exchangers for other production plants are also produced here. Large amounts of reject components and modules arise during running production, especially however during series production start-up of new models. Until several years ago, these parts had to be disposed of externally. But as from 2003, an internal recycling centre has been built up in stages, which

• avoids costs and disturbance to local residents due to external disposal and associated transport movement
• opens up additional sources for profitable returns,
• creates new jobs, including a number of them for staff with limited performance capability,
• provides security against claims, as reject parts no longer leave the production site.

There is a focus with the disposal centre’s processing technology on recovery of plastics from faulty modules and pre-series production. Among these are for example water, oil and charge air coolers, but also large format covers and cladding (trim), electronic modules, and other production items. Jürgen Negelmann, manager of waste management in VW’s plant in Hanover has been involved in development of the disposal and processing strategy and supports the present day-to-day operation in these areas. “Just by processing coolers, which consist of 90% aluminium and 10% plastic, we recover around 8 tonnes of polyamide 6.6 per month – mostly as 30GF [30% glass fibre reinforced versions]”, says Negelmann.

Processing of plastics waste in VW’s Hanover plant started in 2007, based on a multiple-shaft shredder from Untha with a downline separation stage for metals and a M450/300 granulator from Hellweg. This granulator produces high-grade material that can be immediately used in injection moulding. Both granulate produced and the work environment are largely dust-free, due to integrated extraction and dust-removal equipment. End product quality and ease of maintenance were decisive in the choice of the Hellweg granulator, as these aspects promised low operating costs.

Manual disassembly of modules takes place first, separating, for example, plastic parts and the aluminium body of oil and water coolers. Clips, labels and other contaminants are removed, for example, from other materials. Around 20 employees have a secure workplace in this area, some having limited performance capability. Depending on the size and type, the parts then pass through to the shredder, which pre-shreds them down to around 60 millimetres size, and then on to the separation unit, which separates aluminium and other metals out of the material stream.

As the final plastics processing stage prior to dust removal and packing in Big-Bags, the granulator determines the quality of the resulting 8 mm granulate. With around 400 kilograms throughput per hour, it produces consistent particle shape and size, on account of its special cutting geometry – irrespective of the material task involved.

Capacity expansion with proven concept

With increasing success and quantities processed in the recycling centre, the need for high performance shredding & granulation has also increased. According to Jürgen Negelmann: “After around five years of operating experience, consideration was given to additional capacity in both final granulation as well as in pre-shredding. The task was to continue producing high‑grade regrind, in order to be able to obtain reasonable prices in the market, and also to continue operating a manageable solution in terms of effort needed for maintenance. Brainstorming resulted finally in consideration being given to acquisition of a second granulator with high performance capability, which can also directly process large format parts – thereby eliminating pre-shredding in a separate shredder, as well as associated handling.

On account of good experience in the previous years in terms of machine availability and operating costs, a Hellweg granulator came into consideration yet again, in this case a Hellweg M600/45 with throughput of 480-850 kg/h and a standard 8mm sieve. The size of parts to be processed amounts to 300 x 100 mm.

Granulator features include:

Grinding chamber opening: 600 x 500 mm (width x depth)

Motor power:30.0 kW

Low-wear design of the grinding chamber, absolutely necessary when grinding abrasive materials such as e.g. glass fibre reinforced plastics.
The new granulator has also been connected to the dust-removal and packing equipment. As it swallows larger parts without a pre-shredding stage, on one hand it relieves the other (M450/300) granulator installed earlier, on the other hand also the shredder, reducing overall effort for processing with only a small additional need for space. On the subject of maintenance, Jürgen Negelmann says: “Despite around the 1,400 kilograms per shift that the machine shreds and granulates – presently exclusively as PA6.6 GF30 – the granulator runs for three months completely free of maintenance, on account of the wear protection and corresponding blade geometries”. In addition, the wear-protected elements can be individually exchanged and the blades can be easily changed for sharpening. Cutting quality is maintained despite long operating periods between maintenance intervals. The rotor also makes a contribution by being produced from a single metal preform, which also ensures quite running, as well as consistent cutting speed and quality.
Integrated dust removal increases product quality. Here, the material leaves the granulator and enters a “zigzag”-shaped classifier from G.H. Krämer Lufttechnik, which has reliability and low maintenance needs suitable for operation together with the granulator. The company Aurora, which purchases a large proportion of the regrind from VW, has confirmed, according to Jürgen Negelmann, that the equipment produces the best regrind ever offered to the company.

Carefully tried out

At the beginning of the project in 2006, prior to installation of waste processing at VW, trials were made with different disassembled products in order to clarify basic procedures. As work for a diploma thesis, different shredders and granulators were tested in order to investigate optimum combinations in terms of throughputs with different plastics, maintenance effort, regrind quality, variability in processing different plastics, as well as, naturally, costs. The waste disposal company Veolia supported the project, as a company handling part of the residual materials logistics for VW.

The enormous range pf materials plays a large role in the recycling plant planning: aside from PA with different glass fibre contents, PP, ABS, ASA, PE and other materials also arise and have to be processed into pure single-material fractions, among them also special combinations such as PP with air dimples, all of which have to be handled by the granulator, along with solid parts. All these materials, right up to TPE and TPU, can be processed on Hellweg granulators without re-equipping the machine. This ensures high flexibility in the recycling centre.

Business plan fulfilled

Production instead of disposal was the core consideration in preparation of the recycling business plan. There was a nice side-effect: theft of pre-series parts during transport to the waste disposal site, which later appeared on the black market, has now been eliminated -security against claims plays a role too that is not to be underestimated. Despite all of the obvious advantages of in-house recycling, the plant management demanded a business plan, which demonstrated long-term feasibility of the concept. “As planned, we achieve average 70 to 75 percent cost coverage today in waste processing. With further increases in quantities sourced from external VW plants such as Salzgitter, which can supply us by rail, the situation will turn out to be even more favourable”, Jürgen Negelmann predicts. In addition, further waste source materials are being continually tested for recycling capability, which will improve the situation even more. Overall, around 200-200 tonnes/year of plastics are being recycled by VW in Hanover, with a trend pointing to a further increase.

In order to ensure regrind quality, shredding and granulation is accompanied by various quality assurance measures with external supply from other VW Group plants. In general, the type of material is securely identified with the aid of interferometer analysis, in order to produce a pure single-material end product. The laboratory located directly alongside the shredding and granulation facility additionally possesses LFI and infrared analysis technology. The archived organisation of incoming materials control and material flow could also serve to expand the supplier base: recycling may possibly be extended to supplies form VW’s service workshops, which could supply for example bumpers, dashboards and other large volume parts from their repair activities. The quality assurance measures also serve to qualify VW’s recycling centre as a waste disposal business in accordance with the Federal German EtfbV [Entsorgungsfachbetriebsverordnung] regulation and enable pre-registration of the polymer waste material according to the EU’s REACH directive on registration, evaluation, authorisation and restriction of chemicals.

Volkswagen’s plant in Hanover

Around 800 vehicles on average, plus raw bodywork such as that of the Porsche Panamera leave the production halls in Hanover every day. The plant also produces components such as motor parts and heat exchangers for the company’s other locations, all on a production site with an area of more than 1 million square metres.

Hellweg Maschinenbau

Hellweg Maschinenbau GmbH & Co. KG (www.hellweg-maschinenbau.de) is equally a family owned company, which has been designing and producing itself machines and equipment for the past 13 years, particularly for specific customer tasks for customers in the plastics and recycling industries throughout the world. The production programme includes machine-side and other granulators, edge strip shredders, feeding equipment for edge strips, film cutters, extraction and dust removal equipment, including accessories.
 

Photo 1. Jürgen Negelmann, manager of VW’s waste management business has also driven plastics recycling forward.

Photo 2. As part of an increase in production capacity, a M600/450 granulator has been additionally installed, which brings also large lumps without pre-shredding down to granulate in a single-stage process.

Photo 3. Both granulators operate connected to inline dust-removal and Big-Bag packaging equipment.

Photo 4. The M450/300 granulator has been in use for around seven years, reducing a wide range of materials into high-grade granulate.

(Text and photos: M.Droege / PR WORKS)