Premiere on the blue belt

Saving energy through low temperature utilization

For the construction of their new pellets plant, Cycleenergy got drying specialist Mühlböck on board in order to achieve the maximum utilization level with regards to production and power demand.

The implementation brought quite a few additional challenges – but succeeded with flying colors nonetheless.

Right in the middle of the Mostviertel Region in Lower Austria, more precisely in the municipality of Gresten, a pellets plant with quite some distinctive features started operations in April. But first things first.
Cycleenergy was found in 2005 as a supplier of local, decentralized energy solutions. Since 2006, the family business is operating two sites located in Aschach an der Donau and Gresten with 2 MWel each. In 2009, the company acquired the factory in Gaishorn am See with 4 MWel which has been producing an annual output of 30,000 t pellets according to the ENplus A1 standard ever since. Currently, Cycleenergy‘s production output in Lower Austria, Upper Austria and Styria encompasses around 50,000 t pellets/ yr, green electricity suitable for base load, about 100,000 MWh of heat for households and businesses as well as superheated steam for an industrial customer at the site in Gaishorn am See. On average, the Cycleenergy group‘s factories achieve 8400 full load hours per year.

The Gresten site
In the densely wooded region of Eisenwurzen in Lower Austria, Cycleenergy produces more than 16,500 MWh of energy per year. The energy is fed into the local power grid supplying the municipality of Gresten with its approximately 2000 inhabitants as well as surrounding enterprises.
Cycleenergy strongly believes in trustworthiness, a solution-oriented approach and reliability as guiding business principles and was looking for a partner living up to those standards.
This is how kiln drying specialist Mühlböck based in Eberschwang came into the picture. Gerald Kreuzhuber – responsible for sales – is providing project details: A classictype belt dryer with a belt surface of 80 m2 and an output power of approximately 3.5 t/h is used. This is the first time that Mühlböck implemented two super-imposed heater batteries for two different heating circuits. „Thanks to this hybrid construction we can also utilize the turbine‘s exhaust heat with little flow temperature for sawdust and wood chip drying“, Kreuzhuber informs.
Other specifics of this pellets plant are the limited space that the company had to adapt to as well as particularly strict regulations concerning dust and noise emissions. The latter problem was solved by building the system with belt dryer into a hall. Splitter silencers ensure that even the fresh air intake causes remarkably low sound emissions.

Energy-efficient dryer operation
The dryer‘s energy consumption is optimized by means of four independently controlled fans. „It is not necessary to operate all fans at full speed all the time. Different control modes allow Cycleenergy to operate the dryer according to the current requirements either in a throughput-optimized way or depending on the available thermal energy. Regardless of this operating mode, optimal air saturation and therefore energy-efficient low-emission operation of the dryer is always a priority“, as Kreuzhuber elaborates.
He further explains that thanks to this construction method Mühlböck managed to „comply with what can probably be considered Austria‘s lowest permissible dust emissions even without external filter systems.“

Extensive safety measures
Safety is ensured by means of the installed fire protection and sprinkler system which is a VdS-approved automatic extinguishing system with a multitude of components for fire detection and extinction. „The system exceeds the legally required standards by far“, manager Christoph Bruckner informs and adds that workplace safety and fire control have top priority within Cycleenergy‘ s company philosophy.

Optimized feed paths
Another characteristic is the layout of dosing and return screws. By means of an additional return screw, excess material is not fed back simultaneously but rather circulated. „This setup reduces screw wear and therefore service and maintenance works“, Kreuzhuber explains. This is particularly interesting for bulky materials such as wood chips. For periods of low heat demand for drying sawdust, Cycleenergy is planning on processing forest wood chips in the belt dryer for the block-type thermal power station.

Demonstrative success
At the end of the project, Bruckner sums up: „The implementation of the pellets plant – from the green field to the finished factory – posed a major challenge. But together with Mühlböck, we were able to realize our plans in no time.“ To offer interested parties insight into pellets production, Cycleenergy developed an integrated presentation in collaboration with This-Play. For this purpose, small LED spots of different color ranges were installed throughout the entire facility. And there is even more icing on the cake that should not go unmentioned: The family business is also welcoming children and introduces them to the world of pellets production in their presentation program „Kids Modus“.

Holzkurier 44/2017 - Vera Bauer, Günther Jauk