Project Rubner/Rohrbach an der Lafnitz

Energy-saving – Progressive kiln meets all customer requirements

Continuous wood drying with the lowest possible energy consumption

When Rubner Holzindustrie planned to expand the existing drying capacities for the Rohrbach an der Lafnitz site, this was a clear task for the drying specialists at Mühlböck.

But at second glance, the big challenges that should be solved here. With the existing low heat energy, the capacity for sideways drying up to 35mm wood thickness should be increased.

At the same time, however, it was also necessary to meet the high quality- requirements with regard to moisture dispersion and wood quality, as well as the available space and additional requirements both for the control software and construction of the Rubner company.

Mühlböck was able to meet all requirements with the progressive kiln Type 1003 with heat recovery and now also uses high standards for continuous lumber drying in Austria for the first time.

Continuous drying for continuous wood production

The company Rubner already has many years of experience with progressive kiln systems and swears by the principle of continuous drying in coordination with the entire further processing.

"In contrast to classic drying kilns, the progressive kilnmoves the wood through the dryer on transport trolleys and exposes it to different climatic conditions," project manager Christian Grilz formulates the principle of the plant. "Depending on the type of wood, the dimension, the initial moisture content and the desired final moisture content, the progressive kilns designed with different climate zones," continued Grilz.

25% lower energy consumption than existing systems

We would like to increase our drying capacity with another progressive kiln, but with our heating system we are at the power limit, "was the main statement from Rubner at the first talks.

However, during the first preliminary talks, it became clear that a custom-made solution was available with the Mühlböck Type 1003 duct dryer, a drying system with heat recovery and a special air circulation for reducing thermal energy consumption.

"This system is not just a heat recovery in the classical sense. Rather, more than 95% of the energy used is transferred from the exhaust air of one drying zone to fresh supply air to another zone. The used energy is used almost twice, "says Mühlböck.

Additional requests were fulfilled

In addition to the requirements of the drying itself but it was also the customer's wishes regarding installation in the factory and additional cultivation of a canopy for the storage of sawn timber implement. "The two project managers of Rubner - Franz Seidl and Rene Karner - gave us valuable input based on their previous experience, but also faced constructive challenges," says Grilz.

However, all requirements have been implemented in the form of innovations such as pegged rail system, optimized transport system or constructive connection of a hall canopy.

Optimized plant assembly within a very short time

In addition to the customer-specific system properties, however, it was also important during installation to comply with the tight planned period of time, as well as not hinder the operation of the existing systems and the entire sawmill operation.

Thanks to the excellent assembly planning, the readiness of the employed fitters, all of them from the immediate vicinity of the company Rubner, and the ongoing coordination with the project managers Hr. Seidl and Mr. Karner not only did the assembly in a very short time but also smoothly.

User-friendly visualization

Especially for the new progressive kiln, the programmers from Mühlböck have developed their own control system based on the latest software from Siemens. An intuitive operation, as well as a clear and concise graphical representation in connection with the output of all information in plain text form are the essential features. Interfaces to mobile data acquisition devices ensure perfect data handling.

The complete safety technology was also designed with the greatest possible operator safety, taking into account the simplicity of operation.

Confidence in plant performance and perfect execution

"Decisive for the award of the contract to Mühlböck was, in addition to the convincing technology and the promised power and consumption values, above all the fact that a comprehensive package of services in connection with the construction of the kiln was offered," one learns from Rubner. In addition to the design and planning of the overall project, this included the preparation of the foundation plan, the heating piping and distribution, the production of the kiln components in-house, the programming of control and customization in house Mühlböck, the entire assembly and commissioning by own staff, and the follow-up and optimization of the plant by a Mühlböck technician. "For us, this meant a reduction in interfaces and simplification in project development," says Rubner, summing up the reasons for the award of the contract to Mühlböck.

"We have never regretted this decision until today", one learns after completion of the project by Fa. Rubner on.