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Flexibility opens the door to RDF growth

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German family company Helmut Westarp has become one of the country’s leaders in producing refuse-derived fuel (RDF). It witnessed different qualities of material coming in for processing and started looking for ways to treat both medium- and high-calorific fractions.

At its headquarters in Aschaffenburg, Bavaria, waste manager Helmut Westarp processes surplus production material, bulk waste, large packaging material and unsorted commercial waste to generate refuse-derived fuel (RDF) of different qualities. Westarp’s facility runs in two eight- hour shifts, five days a week. Fractions with a medium calorific value are sup- plied to waste incineration plants and cement works, which are the main customers. High-calorific waste can also serve as a substitute for fossil fuel in the main burners.

The family-operated company was founded in 1967 and now caters to some five thousand customers in vari- ous industries in the Rhine-Main area. Always striving to innovate its busi- ness, the company wanted to upgrade its existing recycling line to a more flexible one capable of coping with the varied waste stream.

Versatile partner

To avoid interfaces and minimise its administrative costs, Westarp looked for a partner company that could provide a processing line from a single source, from project planning to installation to commissioning. It settled on German technology provider Vecoplan.

‘Our task was to supply an energy-efficient system with high availability and high output for generating RDF of high quality,’ points out Vecoplan’s sales manager Tim Hamer. ‘Westarp wanted to be able to handle different kinds of fuels of different combustion quality. This new system had to be integrated into its existing processing line.’

Vecoplan worked closely with its cus- tomer to design the system for high performance and the ability to consistently generate different kinds of fuels. The result: two high-performance pre-shredders for feeding material to a plant with various settings for sorting and shredding requirements.

For quality assurance, the shredders are flanked by processes for removing ferrous and non-ferrous materials, several near infra-red separation processes and two air separators. Vecoplan also supplied all the equipment: trough conveyors, pendulum distributors, chain conveyors and double screw conveyors.

No interruptions

Material is mostly collected by Westarp’s own transport service. Commercial waste has a bulk density of 200 to 250 kilogrammes per cubic metre while the density of production waste is 120 to 180 kilogrammes per cubic metre. Employees pre-sort the material using grapples and wheel loaders and pass it to the pre-shredder.

When starting the first contract in 2018, Vecoplan’s engineers had to take into account the existing layout at Westarp. The new systems had to be integrated into the company’s sorting facility. Space was limited, so the technology provider determined an optimised set-up based on 3D measurements. To generate output of good quality, the machines were configured in advance to handle different kinds of input material.

‘Throughout the process of implementing the extensions and modifications, it was important to permit only short interruptions,’ said Hamer. ‘This allowed us to hold production downtimes to a minimum.’

Vecoplan’s VVZ 2500 double-shaft shredder then reduces the material to a particle size of less than 200 mm. This material is continuously fed to an adjoining conveyor belt. The belt passes an overbelt magnet which removes ferrous material. A three- fraction air separator then divides the material into heavy, medium and light fractions.

Adjusting the fractions

The light fraction can additionally be separated into high-calorific and medium-calorific fractions depending on the setting. ‘The fractions can be adjusted by the company according to market requirements and combined operation is also possible,’ Hamer explains.

Another overbelt magnetic separator removes ferrous materials from the heavy fraction. The heavy material is then conveyed to a non-ferrous metal separator. Non-ferrous metals are removed by the eddy-current method and collected in a separate container.

The medium fraction generated by the air separator is also freed of ferrous metals, after which it is passed to a screen that removes pieces larger than 200 millimetres. Large material is collected in a bin and delivered to the pre-shredder as needed. Residues from the sorting facility are also collected in the bin.

Material smaller than 200 millimetres is deposited in a bin below it. Westarp supplies these medium-calorific RDF to customers for thermal utilisation.

The light fraction is likewise conveyed to an overbelt magnetic separator after air separation. The material then goes to re-shredding. A pendulum distributor evenly distributes it between two VEZ 2500 TT re-shred- ders which Vecoplan has developed especially for RDF processing. This series is equipped with a high-perfor- mance cutter that is designed for maximum throughput.

When a machine is being serviced, Westarp can continue running the line with the other one. The re-shredders reduce the light fraction to a particle size of less than 30 millimetres at throughput rates of 15 tonnes per hour per re-shredder. A drum magnet extracts further ferrous impurities from the re-shredded material.

Three modes

In late 2020, Vecoplan provided an extension to increase the system’s flexibility. The goal was to significantly increase throughput to 50 tonnes per hour while ensuring greater flexibility. For this, Vecoplan installed an additional single-shaft pre-shredder from the VEZ 3200 series to generate material with a particle size of less than 250 millimetres. Ferrous material was then removed and an air separator created heavy and light fractions.

‘This new part of the facility now supplements the existing one and can be operated in three different modes,’ Hamer says. One mode is for production of high-calorific RDF. After pre-shredding and separation of ferrous material, the light fraction is fed to the conveyor belt. The re-shredder then processes it to high-calorific RDF.

The heavy fraction is then merged with the medium fraction from the existing facility and further processed. In the second mode, Westarp can produce medium-caloric RDF. After pre- shredding and separation of ferrous material, the material is conveyed to the heavy fraction of the air separator and merged with the medium fraction of the existing facility, where it is further processed.

Operating mode three feeds the material to the sorting facility. After pre-shredding and separation of fer- rous material, the material is fed to a separate belt conveyor via the heavy and light fraction of the air separator of the sorting facility. The sorting facility can process a wide range of materials for recycling.

The global value of the waste-to-energy market exceeded US$ 35 billion (EUR 32.5) in 2019, Statista reports. Its provisional figures for 2020 and 2021 are US$ 36.7 billion and US$ 38.4 billion respectively. By 2027, the waste-to-energy sector is expected to be worth over US$ 50 billion.

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