Belt dryer BT for bark and sawdust
in Chile
Dryer type: BT 1-6200-61.5
Dryer output capacity:
bark and sawdust: 46.0 t/h from 64% to 49%
From sawmill waste to pellets – Ladenburger GmbH is exploring a new form of value creation with STELA RecuDry®
In any sawmill, it is inevitable that sawdust and woodchips will be produced. These residual materials have long been regarded as a byproduct with limited value. Ladenburger GmbH in Bopfingen-Aufhausen has turned this idea on its head: with a new pellet production line and a STELA BTU RecuDry® 1/6200-60 belt dryer, the sawmill is now processing all the byproducts of its sawing activities into high-quality pellets – with efficient use of energy, low noise and a significantly smaller carbon footprint.
At a glance
Industry: Wood Industry / Sawmill & Pellet Production
Challenge: Cost-effective and more sustainable utilization of sawmill by-products
Solution: STELA belt dryer with RecuDry® technology for energy-efficient drying as the basis for pelletizing
Dryer used: BTU RecuDry® 1/6200-60 with heat recovery
Products to be dried: Sawdust and wood chips (sawmill waste)
The Challenge
Sawmills like Ladenburger produce large quantities of waste wood – sawdust, shavings and woodchips are created as direct byproducts of the timber sawing process. Until now, the site did not have its own pellet production line; the waste materials were reused externally.
The decision to set up a complete pellet production line at the Kerkingen site came with two key technical requirements:
- Reduction of moisture: Sawdust and woodchips with an input water content of around 45% have to be dried to approx. 10% – the prerequisite for stable pellet quality.
- Compliance with emissions limits: The site has strict official emissions limits that had to be taken into consideration in the design of the drying system from the outset.
In addition, operation of the system had to be made as energy efficient as possible – because drying is the most energy intensive step in pellet production.
The solution: BTU RecuDry® 1/6200-60
STELA Laxhuber designed a BTU RecuDry® 1/6200-60 belt dryer for Ladenburger – the high-performance variant of the STELA belt dryer with integrated heat recovery using the patented RecuDry® technology.
In this design, the system dries around 30 t/h of sawdust and woodchips from a water content of approx. 45% to approx. 10%. The heating medium is hot water at 90–100°C – a heat source that is available in many timber processing companies from their own biomass incineration and is ideal in combination with the STELA low-temperature system.
RecuDry® – heat recovery at the heart of the system
For Ladenburger, the key factor in selecting the type of dryer was the integration of the patented RecuDry® heat recovery system. The system divides the drying process into two modules:
- Recu module: Some of the exhaust air is recirculated, heated again and optimally saturated with moisture – this makes maximum use of the energy that is fed in.
- Condensation module: The energy-rich recirculating air is brought to condensation point. The latent heat released in this process is used to pre-heat the fresh air via an air-to-air heat exchanger.
The result:Only around 8200 kW of heat is required to dry 30 t/h of sawdust at an outside temperature of 10°C – a figure that a conventional belt dryer without heat recovery would exceed by some distance with this throughput.
Emissions-compliant design thanks to individual planning
Compliance with strict emissions limits was one of the central requirements of this project. Low-temperature belt dryers fundamentally have the edge over high-temperature processes: lower process temperatures mean lower VOC emissions and smaller exhaust air volumes.
At the same time, the specific situation at the Kerkingen site required customised planning and design. STELA adapted the system to the specific local requirements – from working out the exhaust air routing to the treatment of wastewater. Commissioning took longer than originally planned because of the strict requirements for the variability of the drying performance; but STELA was able to make all the adjustments that were required.
Feedback from the customer
This was the best value for money. Heat recovery was a particularly important consideration in our decision to buy this system. The relatively low energy consumption in conjunction with heat recovery makes a significant contribution to reducing the carbon footprint of our pellet production.
Matthias Gerstmeyer, Head of Production, Kerkingen Sawmill, Ladenburger GmbH (in the photo on the left) and Alexander Miko, Plant Operator at the Kerkingen Sawmill (right in the photo)
Conclusion and outlook
With the new drying and pellet production line, Ladenburger has completed an important strategic step: a byproduct from the sawmill has been turned into a high-quality, marketable end product. Summary of the most important outcomes:
- New value creation: Sawdust and woodchips are processed entirely on site into pellets – external recycling is not needed.
- Larger product portfolio: Ladenburger is now able to process a large proportion of its own sawmill byproducts and achieve additional value creation for the company.
- Smaller carbon footprint: The low specific energy consumption thanks to RecuDry® delivers a measurable reduction in CO₂ emissions from pellet production.
- Emissions-compliant production: All official limits have been met – thanks to customised planning and design.
- Stainless steel construction: The design of important components in stainless steel impressed Ladenburger and ensures that the system has a long service life.
The investment is a prime example of a wider trend in the timber industry: cascading use of resources and a circular economy as an economically attractive strategy – not just as a sustainability goal.
About Ladenburger GmbH
The timber mills of Ladenburger GmbH are among the leading wood processing businesses in Europe. Founded in 1938, the company now has around 800 employees at four production sites in Germany, namely in Aufhausen, Bopfingen, Kerkingen and Geithain. At the Kerkingen site, Ladenburger operates a sawmill with an annual log cutting capacity of around 1 million cubic metres. Its broad product portfolio includes sawn timber, glued laminated timber, OSB boards, façade products and – since the new investment at the Kerkingen site – high-quality wood pellets. The company is PEFC-certified, and sustainability and responsible use of resources are firmly anchored in its corporate values.
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Contact person
Low temperature, continuous dryer, circulating dryer – not sure what’s the best choice for you? Our experienced colleagues will be happy to help you find the best solution for your product. Please feel free to contact us without obligation.
Telephone +49 8724 899-10
Email sales[at]stela.de
