Mayr-Melnhof Karton in Kolicevo, Slovenia produces premium recycled and virgin fiber-based cartonboard grades on two board machines with grammages between 200 and 500g/m². Key markets are food, cosmetics, and pharmaceutical packaging, as well as other demanding applications.

Strategically located to serve Eastern and Western European markets, the Kolicevo mill partners with other Mayr-Melnhof sites to produce branded white top and folding boxboard grades to meet exacting specifications of customers.

Mayr-Melnhof Karton products are sold to more than 100 countries worldwide. In seven European mills on nine board machines with an annual capacity of more than 1.7 million tons, MM Karton produces a wide range of white lined chipboard and folding boxboard qualities, as well as offset and flexo liner.

Recently, a new dryer management system for BM3 has contributed to running more efficiently at higher speed, gaining flexibility for grade changes and reducing energy costs.

Looking back, it’s easy to see why Mayr-Melnhof (MM) in Kolicevo, Slovenia chose better drying control as part of its upgrade to BM3. Having retrofitted a three-layer Fourdrinier with multiple drive units, MM Kolicevo embarked on a strategy to turn the dryer system from problematic to opportunistic, delivering smooth operating conditions and further gains in quality and flexibility.

Says Rado Kunavar, MM Kolicevo’s technical director, “A comprehensive drying survey showed potential for improving quality and efficiency and higher targeted speeds. In addition, we wanted a vehicle to help operators focus on continuous improvement.”

“Higher drying capacity and tight control of the drying system allow us to run at optimum speed without worrying about varying operating conditions based on the sheet being produced and other dryer drainage issues. The Kadant DMS™ control system manages all the drying variables for us. Flooding, which was common in the past, doesn’t happen. Sheet breaks are down and recovery time after a sheet break is minimized.”

Adds Joze Kopac, Engineering Investment Department Project Leader, “A mindset shift to optimize drying is so much easier, because models for every key function are in the system, visible, and easy to read graphically on any monitor as part of our DCS. Operators like the fact that steam system set points are continuously adjusted automatically as grades change. Stability and efficiency of the dryer section are now the norm. Our DMS system gives operators the ability to manage drying in a holistic and specific way.”

Drying Optimization Benefits

• Energy Saving: 900 kg/h of steam
• Energy Saving Electricity of 5 kwh/t
• Reduced the number of sheet breaks
• Time to recover to quality parameters after a sheet break reduced by 50%.

Rebuild First

In 2016, MM Kolicevo upgraded BM3 to improve quality and gain flexibility for its customers in Eastern and Western Europe.

The rebuild provided higher quality cartonboard, including a constant stable surface and an optimized stiffness ratio (L&W). Its GT2 cartonboard brand Belpak™, highly valued for pharmaceutical and hygiene products, stands out more than ever with excellent stiffness values.

Road Map & Options for Steam & Condensate Control

The MM Kolicevo team worked on a drying control strategy to achieve the maximum results with minimal efforts. The first goal was to address problems that were creating chronic problems in production.

According to Graziano Buttiglione, Technical Director for Kadant Johnson Systems Division in Europe, “A regrouping of the dryer steam sections, combined with individual controls at the wet end dryers, made it possible for the machine to achieve the required drying strategy for guaranteed sheet quality and reduced steam losses to the condenser.”

The entire machine was equipped with new rotary joints, modern cantilever stationary syphons and Turbulator^® bars, critical to improving the CD dryer surface temperature profile and achieve a drying capacity increase. Also, the vacuum system was totally replaced by a direct injection water jet heater, a simple device able to replace a large water condenser and vacuum pump.

Notes Kopac, “A pre-condition to excellent results was training of operators for the DMS control system, new valves, syphons, and Turbulator bars. Without a big picture capability and know-how of the DMS system and the new hardware, we could forget about going beyond 500 mpm.”

Now, MM Kolicevo is looking to make even higher speed production the new normal, while they continuously fine-tune grades to meet niche markets.

“How our board looks and feels in the hands of consumers is what really matters. Using recycled fiber, saving energy that is unseen, but important, too as part of our sustainability commitment,” comments Kunavar.

Within this series of articles, the description of the fourth industrial revolution has been explored and defined within Kadant. This article highlights the benefits possible with the evolution of technology and smart manufacturing. Read about the beginnings of the fourth industrial revolution in Part 1 and in Part 2 learn how Kadant is leveraging Industry 4.0 in the paper industry.