Energy chain system for the composting plant

Automated composting: Reliable supply of energy and process media under unfavourable conditions

In a composting plant, every single component must be designed for a long service life, because moisture and organic acids severely damage the plant. At the AVG (Abfallentsorgungs- und Verwertungsgesellschaft Köln mbH) plant, igus has now installed two energy chain systems for the transfer units in the central composting hall, which were configured precisely for these applications. Both systems were designed identically.

Profile

Composting plant

Problem

AVG's composting plant in Cologne processes bio-waste from Cologne households, green waste from gardens and forests, and organic waste from businesses into compost in various classifications. The central process step on the way from waste to compost takes place in a huge hall divided into two fields. Each field is about 26 metres wide and 150 metres long. An automatic heap handling device, similar to an indoor overhead travelling crane, travels above it, distributing the source material evenly in the hall with a conveyor unit.
These perform all essential functions in the composting hall fully automatically.  In order to supply the crane bridges and transfer units with energy and signals, chains and guide troughs from a competitor were previously used, which after ten years of continuous operation showed strong signs of wear and even led to the failure of the system. The reason: The heap handling equipment was supplied via a normal gliding chain - that such a chain shows wear with this length and its own weight is unavoidable and does not correspond to the latest state-of-the-art technology.
Furthermore, the careful selection of materials is an essential prerequisite for a long service life, because the atmosphere in the composting hall is very corrosive: organic acids are released during the composting process. Together with the very high humidity, this creates a type of climate that many materials cannot cope with: Even galvanised metal components corrode quickly here.

Solution

After the bad experiences with the competitor's gliding energy chain, the management was looking for a replacement. The most obvious solution was to ask the supplier to replace the chain. At the same time, however, they also made enquiries at igus. The specialists looked around on site and projected an alternative solution according to the current state of the art in a very short time. The fact that a gliding chain shows wear in the application given its length and dead weight is unavoidable and does not correspond to the latest state-of-the-art technology. igus therefore suggested distributing the weight on two chains that travel in opposite directions.An E4/4 roller energy chain of type 5050R with roller guide was therefore used to supply the crane bridges and transfer units with energy and signals, together with a guide trough of almost 150 metres in length. This system also proves itself in dirty and humid environments - and it was designed for long travels. A flexible interior separation ensures that the cables are guided in an orderly manner during movement. The cables within the chain are thereby responsible for the mobile media, energy and signal supply of the system. To take into account the aggressive environmental conditions, the guide trough is made of 316 stainless steel, which is resistant to corrosion in the long term.
"Organic acids are released during the composting process. Together with the very high humidity, this creates a climate that many materials cannot cope with: Even galvanised metal components corrode quickly here."
 
Dipl.-Ing. agr. Michael Tegetmeier, Operations Manager of the composting plant on the challenging environmental conditions 
energy chain
energy chain

Fast assembly, satisfied customer

With these advantages, it is not surprising that AVG opted for the solution from igus - especially as igus had experience in equipping a similar composting plant in Erftstadt, 30km away. The igus project team was also convincing in terms of speed. Michael Tegetmeier: "We were under time pressure because we wanted to install the new energy chain at a time when there was little compost." Speed was also the order of the day during installation so as not to delay the composting process. This task was taken over by the operating staff under the guidance of a supervisor from igus. 
The new system was installed without any difficulties and completed the continuous operation without any problems. Michael Tegetmeier is satisfied with the collaboration - and with the new energy chain system as well: "AVG can be sure that it is using the latest and most reliable technology here. Despite the rather unfavourable environmental conditions, the system is expected to have a long service life. An annual inspection by igus will ensure that the user's expectations are at least met, if not exceeded, in these aspects as well.