Thrilled by the drying quality: owner and managing director Anssi Hintsa and sawmill manager Toni Ylivainio in front of the two Mühlböck plants © Raphael Kerschbaumer
“We have been working with Mühlböck since the early 2000s. We are both family businesses and agree that mutual trust is crucial for a successful and long-term partnership,” Anssi Hintsa, owner and managing director of Kohiwood, says about the decades-long cooperation with Mühlböck. However, trust is not the only reason why the successful entrepreneur relies on technology from Upper Austria. “When it comes to wood drying, you absolutely need experts, and you can tell at every moment that Mühlböck’s specialists know exactly what they are doing.”
Focus on small-diameter log wood
At Kohiwood, the need for drying solutions is considerable and keeps growing. At the site in central Finland, over 12 million logs a year are processed into high-quality lumber products for international export markets or into raw wood for the in-house production of solid wood panels. Years ago, the company has specialized in log wood harvested as part of thinning measures, which explains the large number of logs which are processed at the site. The locally sourced pine and spruce logs have an average diameter of around 12 cm.
“All the lumber has to be dried today”
Depending on the market conditions, Kohiwood either focuses more on its in-house panel production or sells the lumber both on the domestic and international markets. “Our high-quality log wood and lumber are highly valued worldwide,” Hintsa says. In the past, a large part of the products was sold fresh. For the entrepreneur, this practice has become nearly impossible. “Many of our customers from the MENA region buy at irregular intervals and in bulk. Fresh lumber is rather difficult to store, though. Moreover, the strikes in Finland, which have been going on for weeks and severely limit foreign trade, are putting massive pressure on us and are causing our stock levels to continue to rise. Without the ability to dry all the lumber to a high quality, our business model would probably no longer be viable today.”
Continuous expansions
Buffer for the weekend: On average, one dry lumber package leaves the kiln every four hours. To also get through the night and weekend without any issues, eleven buffer areas in front of and behind each kiln were included in Mühlböck’s plant design © Raphael Kerschbaumer
Thanks to ongoing investments and capacity expansions, Kohiwood can now dry all the lumber produced at the Soini site. Six Mühlböck fresh air-exhaust air drying kilns, which still run smoothly after over 20 years of continuous use, and two 1003 Premium continuous kilns are used to dry the green lumber. The first continuous kiln was installed in 2016, and the second was put into operation at the start of this year. “The quality of continuous lumber drying is unbeatable,” Hintsa says. “The new continuous kiln is impressive in terms of energy consumption, too. Plant efficiency is an important aspect for us. We operate all drying kilns almost exclusively with our new 6 MW biomass plant. The constant power demand of the dryers reduces consumption and has a very positive effect on overall grid stability,” sawmill manager Toni Ylivainio adds.
Same performance with less energy
Sophisticated technology: Thanks to intelligent drying control, different types of lumber can be dried simultaneously in the flow-through process … © Raphael Kerschbaumer
Resource efficiency is a top priority for Mühlböck – and not just since biomass and sawmill by-products have been selling at good prices on the market. “At Mühlböck, we realized a long time ago that plant efficiency is key, both economically and in terms of energy consumption,” Richard Mühlböck, CEO of Mühlböck, tells us. According to the Upper Austrian plant manufacturers, the 1003 Premium continuous kilns save up to 50% of energy compared to conventional systems. This is possible thanks to a sophisticated interplay of different drying zones inside the kiln, complemented by a heat recovery unit which consists of several air-to-air heat exchangers.
… for example, 75-mm-thick pine boards (A) and 43-mm-thick spruce boards (B), both of which are dried to a different target moisture content © Raphael Kerschbaumer
This way, no additional energy is needed for the entire pre-drying process. “With our new systems, steam clouds above the dryers are basically a thing of the past. We manage to reintegrate almost all the waste heat into the process and thus make the best possible use of the generated heat,” Mühlböck explains.
Optimized for the specific application
“Wood that was harvested as part of thinning measures is particularly difficult to dry because of its varying wood moisture content. This was also new and a challenge for Mühlböck. The company made a great effort from the beginning to get the last bit of potential performance and efficiency out of the plant. Numerous tests were done here on site until the best results were achieved. That’s what commitment and dedication look like,” Hintsa praises Mühlböck’s technical department. “The positive experiences from the day-to-day work with the first continuous kiln made last year’s decision easy for us. I didn’t hesitate for a second to award the contract to Mühlböck again,” he concludes, satisfied.
