Energy efficiency for 630,000 tons of cardboard

When it comes to the production of recycled cardboard for the folding box and plasterboard industry, WEIG-Karton's principles of safety, sustainability, and innovation are a driving force. That is why the company has implemented comprehensive modernization improvements to its electrical equipment and in doing so, opted for molded case circuit breakers from Siemens.

Whether in the form of a shoebox or as a container for take-out food - there are myriad uses for folding boxes in everyday life. Just how much know-how goes into the production of this type of folding box packaging is well known to Moritz J. Weig GmbH & Co. KG, based in the town of Mayen in the Eifel region of Germany. The family-run group of companies specialized on recycled cardboard for the folding box and plasterboard industry, and is divided into the three business units of recycling, cardboard and packaging. These cover the entire process: from recycling to create raw material from recovered fiber and cardboard production right through to further processing in packing material manufacturing. For production, the business unit Weig-Karton at the Mayen plant location plays a key role, as the annual capacity of its two cardboard machines is around 630,000 tons of folding boxes and plasterboard.

Systematic energy management

Weig-Karton places great value in the economic and ecological sustainability of its production: Through the power/heat cogeneration systems installed in its power plant, the steam and power demand is covered efficiently. Excess waste heat is supplied to the district heating network in the town of Mayen where the production is located. Moreover, closed circuit systems and the company's own wastewater treatment plant also minimize water usage. Systematic energy management in accordance with the relevant applicable directives has been supporting these measures for a number of years now. 


The re-certification of energy management according to the current ISO 50001 standards in 2012 brought the topic of power monitoring even more strongly into focus. In particular, the search for a solution to monitor electrical energy flows proved complex. "After all, in the environment of the two board machines and the wastewater treatment plant alone, we have several hundred loads, which have to be individually recorded and evaluated," says Thomas Ganster, who is responsible for energy and energy management at Weig-Karton.

Energy flows made transparent

The electrical engineering experts at Weig-Karton Manfred Borsch (Head of Electrical Instrumentation and Control, EI&C Project Planning) and Christof Schnall (EI&C Project Planning), found what they were looking for at Siemens: The powermanager power monitoring software monitors and archives electrical parameters, like voltage, current, power, energy values, and frequencies, thus creating an important prerequisite for transparent analysis of energy flows. In terms of hardware, powermanager only requires a Windows PC and a LAN network.

The power averages of the characteristics monitored are thus displayed and compared. Also illustrated in the display are power distribution faults, permitting a fast response. The measurement of the electrical power data is handled directly via the measuring devices from the Sentron Portfolio. A number of years ago, the engineering technologists at Weig installed several PAC measuring devices in combination with 3VL molded case circuit breakers and 3WL air circuit breakers.

Modernization of the 400 V low-voltage distribution

The power monitoring solution proved successful. "That was ultimately what prompted us to modernize the entire 400 V low-voltage controls and distribution," recalls Manfred Borsch. The prerequisite for this new solution was the latest generation of 3VA molded case circuit breakers. The models in the 3VA2 series come with an integrated metering function for the detection of current, voltage, and power values. 


At the same time, the 3VA molded case circuit breakers perform all the functions of powerful protection equipment: Via bus systems, they report critical system states to higher-level systems. This means the switches also comply with all the requirements for operation in Industry 4.0 environments. The comprehensive selectivity of the molded case circuit breakers ensures that only the actual system component affected by the fault will be disconnected. Christof Schnall also points out: "Maximum availability is a top priority for us, because our machines run 24/7 and cannot be stopped just like that."

Easy configuration and commissioning

At the end of 2017, the plan was implemented: The existing fuse switch disconnectors in the entire Weig-Karton plant in Mayen were gradually replaced by some 800 communication-capable molded case circuit breakers from Siemens. In addition to the large number of devices involved and downtime being kept as short as possible, another advantage of the new molded case circuit breakers is that configuration and commissioning can be carried out using the powerconfig configuration software. "This greatly simplifies parameterization and also speeds up installation," says project planner Christof Schnall, speaking from experience.

The mechanical design of the existing switchboards was still able to be used following the upgrade, as was the cabling. However, the existing copper bars have been replaced by a new busbar system. Individual downstream fuses have been replaced by molded case circuit breakers in the 3VA1 standard version. Compared to the previous solution, they not only reduce the wiring outlay, but also feature a very compact design. Where very high rated currents are required, 3WL air circuit breakers from the Sentron portfolio are used. Individual PAC measuring devices are also part of the modernized plant engineering.

In the environment of the two board machines and the wastewater treatment plant alone, we have several hundred loads, which have to be individually recorded and evaluated.
Thomas Ganster, who is responsible for energy and energy management at Weig-Karton.


Picture credits: Siemens AG / W. Geyer

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