Wasting no energy: green power from green waste – using power technology by Doppstadt

Green waste and untreated wood are first-rate energy sources when properly recycled. This is, of course, common knowledge in the Japanese prefecture of Gunma. There, the authorities have entrusted local Doppstadt partner Sun Earth with finding an efficient technical solution for the process of thermic recycling.

To get to the point immediately: Doppstadt has delivered on all accounts – in the shape of an integrated, individual plant concept realized for nominal buyer Green Material, including pre- and fine shredding systems as well as components for the deposition of metals and screening. Since January, this one-stop example of processoriented recycling technology has been in operation.

With the pre-shredder DW 306 Ceron Type B, the new fine shredding system AK 640 VE and the trommel screen machine SST 725 the forward-looking Doppstadt plant in Japan is prominently cast. Combined intelligently and efficiently, the components take full advantage of their strengths, providing homogeneous, high-quality and metal-free material to be used for thermic recycling purposes.

The "transformation" of the input material takes place in four stages. Following the pre- and fine shredding steps, metallic contaminants are removed and the material is separated into fine, finished and oversized fractions. The oversized grain will be automatically circulated back into the fine shredding process until it meets the requirements of the finished product. If there is no need to run through the entire process chain, the Doppstadt plant can be flexibly used for partial processes as well.

Work steps at a glance

The DW 306 Ceron Type B opens proceedings. The machine receives the input material from a rehandling excavator for the coarse shredding procedure in which the roller teeth break the material through a shredding comb. A conveyor belt then tranfers the mixed fraction to the AK 640 VE where the fine shredding takes place. En route, an overhead magnetic system separates ferriferous contaminants from the wood. The procedure is repeated right before the material enters the screening process.

The trommel screen machine SST 725 finally takes care of the proper granularity of the material is. It screens out the fine fraction, i.e. grain sizes of less than 10 mm. The targeted product size will be bewteen 10 and 50 mm, depending on customer requirements. Oversized particles are automatically transported back to the fine shredding process to be processed one more time. This recirculation process only ends when the entire material fits the size requirements of the finished product. The screening procedure allows for coarser shredding with a substantially reduced fine grain portion, thereby affecting the Gaussian distribution in favour of less tool wear, energy consumption and fine grain.

Proven and tested in the Far East

This groundbreaking design of an integrated recycling plant is not the first assingment Doppstadt has received from Green Material. The Japanese company has relied on the innovative skills of the recycling specialist and the experienced support from the hands of local Doppstadt partner Sun Earth Co. Ltd., Yokohama (www.sun-earth.jp) for many years. Worldwide, Doppstadt employes a tightly knit dealer network of 42 seasoned partners in 45 countries.