Strong teamwork brings success to SCA Obbola

The kraftliner mill in Obbola is one of SCA’s two mills that serve the containerboard business area. Per Strand, Project Director of Expansion Obbola at SCA, explains the reasoning behind the investment. “The containerboard segment has been growing steadily for several years, driven by increased internet shopping and greater demand in the industry. With the global containerboard market growing steadily at around 3 percent annually over the last two to three decades, and a total volume now close to 200 million tonnes containerboard, we saw a growth opportunity and decided to increase Obbola’s total kraftliner production capacity from 450,000 to 725,000 tonnes per year.”

SCA Obbola’s new Valmet TwinRoll washing press. Per Strand, Project Director of Expansion Obbola at SCA, talks with Åsa Arencrantz, Marketing Director, Fiber Processing Business Unit at Valmet.

With this investment, SCA Obbola will be able to meet increased demand for sustainable packaging and significantly reduce its carbon footprint.

Valmet a key partner in the project

Valmet has a long-term cooperative relationship with SCA Obbola and has delivered cutting-edge technology in the past. The paper mill in Obbola is quite modern, and its previous investments and upgrades have paved the way for this expansion. The entire Expansion Obbola project includes several subprojects, and Valmet has successfully delivered the equipment for the fiberline upgrade and the lime kiln rebuild.

Valmet’s 72-meter lime kiln at SCA’s Obbola Paper Mill in Umeå, Sweden.

“Valmet presented an attractive solution for the Expansion project. We’ve also been very satisfied with our previous Valmet products and services. Valmet’s technology is familiar to us, and we’ve enjoyed well-executed collaborations and projects together in the past,” explains Strand about selecting Valmet as a supplier in this project.

Innovative new fiberline concept

The Obbola paper mill’s fiberline needed several modifications to handle the increased pulp flow. The existing four refiners have been replaced by two Valmet Optifiner RF5 units as the main line hot stock refiners and one Optifiner RF4 as the reject refiner. This was a groundbreaking innovation because these refiners have never previously been used in this position. Optifiner RF is well known for its superior performance in second stage, reject or stock preparation refining, but it is now being deployed as the first stage refiner in a high kappa line.

A new Valmet lime kiln reduces SCA Obbola’s CO2 emissions by 20,000 tonnes per year.

“We’ve verified that we can run a conical low-consistency refiner in this demanding position at a very high kappa, with excellent results, and SCA Obbola is the first customer with whom we’ve launched the new concept,” says Jan Laredius, Senior Product Manager at Valmet. The mill’s existing Valmet TwinRoll washing press has been supplemented with an additional washing press to handle higher flow while maintaining purity specifications. The two TwinRoll presses will work together in a series, and the fiberline upgrade means the daily capacity has increased from 850 to 1,100 air dry tonnes. “The dilution factor is the same as before the rebuild, but the production and washing efficiency has increased,” clarifies Pontus Rosén, Process Engineer, Pulp & Energy, Fiberline Process & E&I Engineering, Process Engineering, Valmet.

"We’ve been very satisfied with our previous Valmet products and services. Valmet’s technology is familiar to us, and we’ve enjoyed well-executed collaborations and projects together in the past,” says Per Strand, Project Director of Expansion Obbola at SCA (right).

Toward climate neutrality with new lime kiln

Valmet also delivered a new 72-meter lime kiln, powered by 100 percent wood powder firing. The system is equipped with a Valmet Lime Mud Disc Filter producing clean lime mud that is dried in a Valmet Flash Dryer, calcined in a lime kiln and then cooled in a high-efficiency Valmet Rotary Cooler. By investing in a new Valmet lime kiln, SCA has reduced their carbon dioxide emissions by 20,000 tonnes per year. “It was a natural choice to invest in a lime kiln with wood powder firing,” Strand explains, “because we can now increase our capacity and move away from using fossil fuel oil by reusing the sawdust from our own sawmills. This is an important step in helping us move toward climate neutrality.”

Valmet Optifiner RF is being deployed as the first stage refiner in a high kappa line.

Smooth installation and start-up

Just a few months after SCA signed the contract for these projects with Valmet in 2019, the Covid-19 pandemic broke out. “Despite the pandemic, both projects with Valmet have been operating smoothly throughout the project phase, as well as during the start-up,” says Strand. “The implementation of the fiberline equipment went well, with Valmet operating the entire fiberline at the beginning for testing, and it wasn’t long until SCA could take over the operation. The implementation of the new lime kiln also went according to plan,” Strand explains. “The lime kiln operation included a brand-new facility, so testing was naturally a longer process until we got to take over.” Since the start-up, Valmet has been on site to finetune both plants. “Of course, there’s been a few technical and mechanical obstacles, but that’s nothing strange in such big projects. Most of the start-up has been smooth, and we’re very satisfied,” concludes Strand.

Text Isabelle Sundberg

PHOTOS Torbjörn Bergkvist