Organic waste in the form of rotting foodstuffs from supermarkets or leftovers from canteen kitchens which are no longer fit for consumption ends up being thrown away. The potential contained in this is demonstrated by Hybag Automationen AG from Linden in the Swiss canton of Bern. The company produces systems for converting waste into biomass – used as fuel for generating electricity in biogas installations.
A particular challenge in this process: The biomass must not contain any remnants of packaging. It does however often happen that the plastic, cardboard or string is not removed from foodstuffs before they are thrown away. So the “Tutto” system sorts out such non-biogenic waste during the production of the biomass. And a fan from ebm-papst plays an important part in the process.
Patented separation system
Following delivery in a tipping trough, the raw material is conveyed into an intermediate bunker, where the waste is thoroughly mixed before being transferred to the separating hammer mill. “Here a patented system separates the packaging from the organic material,” explains Anton Berger, managing director of Hybag AG. “The individual hammers crush the entire raw mass and the light packaging material swirls up into the air.” As soon as this happens, the foreign matter is propelled into a separate container by a jet of air.
Out with the foreign matter
To keep the entire system operating at high speed it is important to eject the packaging material quickly from the separating hammer mill. So use is made of a compact centrifugal double inlet fan from ebm-papst to intensify the draught of air already produced by the rotation of the hammer mill. “We decided in favour of ebm-papst because the fan not only provides the necessary performance but is also extremely compact. It was also very easy to install in the system,” says Berger by way of explanation.
The intensified draught of air blows all the synthetic materials into a container, from where they can be recycled. Pure biogenic substrate emerges at the bottom of the machine and is then subjected to heat treatment if required for the intended application before being ready for collection. So supposedly useless waste actually ends up generating power in biogas installations.