Shoe factory waste to fuel Vietnamese cement kiln

A solid recovered fuel (SRF) manufacturing plant is being commissioned in Vietnam for cement and aggregates producer Holcim. The plant will process waste from a large footwear factory to produce a fossil fuel substitute that Holcim will use in its cement kiln.

Holcim selected a single-step SRF solution from waste-to-energy equipment specialist UNTHA. The system comprises an anti-explosive Atex-specification XR3000 cutter waste shredder with two 113 kW motors, conveyor, over-band magnet, control room and water-powered fire suppression technology. It is capable of processing up to 10 tonnes of material an hour to produce an 80 mm fuel with high (15-20 GJ/t) calorific value. The plant also separates metals for recycling.

The plant was pre-fabricated and pre-assembled in Salzburg, Austria for acceptance testing by Holcim Vietnam. According to UNTHA, this proving phase saw it exceed the requirement to reduce 95% of material to a less than 80mm particle size, with 97% being achieved.

UNTHA’s head of engineering and product management, Christian Lanner, said, “This footwear production waste is an incredibly difficult product to shred, due to the mixture of notoriously tough materials contained within sports shoes. We’re tackling rubber, textiles, plastics, metals, sponge, reinforcements and more. However, we extensively configured, re-engineered and trialled our flexible XR waste shredder – using the client’s own material – until it was perfectly suited to this application.

“We’ve also refined the cutting concept so that it is incredibly well equipped to deal with this demanding waste stream.”