“Minimising environmental impacts was the central point for mill planning. Our goal is to make products of the highest possible quality with the lowest possible environmental impacts. This is why we apply BAT (Best Available Technique) or even more advanced techniques,”says Sari Tupitsa, Environmental Manager of Metsä Fibre’s bioproduct mill project.
During the planning phase of the mill, stakeholders were consulted as part of the environmental impact assessment, and they expressed their views about the project and its environmental impacts. The opinions and observations of local residents were respected and implemented to a great degree.
“Examples include noise barriers that reduce the amount of noise around the mill and cooling towers that disperse heat into the atmosphere instead of the sea. This takes into account ice conditions in the Bay of Bothnia and recreational use of ice-covered areas,” says Tupitsa.
A fossil-free, environmentally efficient mill
Kemi bioproduct mill does not use any traditional fossil fuels. Instead, the mill runs on product gas made from bark, tar oil made of tall oil, and other bio-based fuels.
“The lime kiln also uses product gas generated in the process instead of heavy fuel oil, the fossil fuel that lime kilns usually burn,” Tupitsa explains.
Another goal is to minimise fossil CO2 emissions throughout the mill’s logistics chain. For example, much of the wood is transported by trains running on an electrified track, and electrically powered overhead cranes are used to unload wood in the woodyard.
Superior energy and raw material efficiency
The new mill is also a frontrunner in its use of energy and raw material.
Kemi bioproduct mill produces annually two terawatt hours (TWh) of renewable electricity, which corresponds to 2.5 per cent of Finland’s overall power production.
“The mill will produce 2.5 times the electrical power we need for our own operations, and we will sell power to the national grid. Heat generated by the mill will be used by Metsä Board’s paperboard machine at the Kemi integrated mill and for heating in the City of Kemi,” says Pekka Kittilä, VP, Mill Manager of Kemi bioproduct mill.
In addition to softwood and birch pulp, the new mill will produce bioproducts such as tall oil, turpentine, sulphuric acid and bark. Valuable raw materials will be used as efficiently as possible in the production process. Production side streams will also be used efficiently.
Around half the bark will be gasified and used as a heat source in the lime kiln, while the other half will be sold to customers for bioenergy production. Sludge from the wastewater treatment plant will be made into pellets for use as bioenergy.
Skilled staff are key to ensuring the mill’s environmental performance.
“Our professional employees will run the mill competently and uniformly, ensuring optimal performance and environmental efficiency.”
This article was originally published in Fibre Magazine issue 2022–2023.