Fossil free energy production by 2030 Pulp mills and sawmills can be made fossil free by improving energy efficiency and introducing new technical solutions such as the gasification of wood bark left over from production processes. In 2019, Metsä Fibre’s production was already 96 per cent fossil free.
MARKKU RIMPILÄINEN
In line with Metsä Group’s goals, Metsä Fibre pulp mills and sawmills will stop using fossil fuels in their produc- tion by 2030 at the latest. The Äänekoski bioproduct mill already uses only renewable energy. According to Kaija Pehu-Lehtonen , Senior Vice Pres- ident, Business Development at Metsä Fibre, the solu- tions implemented at Äänekoski can also be applied in other pulp mills. Fossil fuels used in the process will be replaced by biofuels, but the continuous improvement of energy efficiency is also crucial. PRODUCT GAS FOR LIME KILNS Lime kilns have long been the most significant user of fossil fuel in pulp mills. The function of the lime kiln is to process lime mud, or calcium carbonate, into calcium oxide for reuse in the process. The Äänekoski bioproduct mill uses product gas as fuel for the lime kiln, which is obtained by gasifying the wood bark produced as a by-product in the mill process. Product gas is also burned in the lime kiln at the Jout- seno pulp mill. Bark gasification was started there in 2013. When the plant is running normally, it does not need any fossil fuels at all. Fossil fuels are only needed in the event of disrup- tions and in the process’s start-up after shutdowns or disruptions. For the time being, the Rauma sawmill’s lime kiln uses fossil-derived oil as fuel. The mill will further reduce
the use of fossil fuels when the sawmill to be built in connection with it is completed in 2022. The pulp mill and sawmill will form a closely connect- ed industrial integrate. In support of its energy production, the pulp mill will receive sawdust from sawing, and the sawmill will re- ceive all the energy it needs from the pulp mill. The sawmill will be fossil free from the start. The new bioproduct mill planned in Kemi would be 100 per cent free of fossil fuels. BIO-BASED START-UP FUELS ON THE WAY Fossil fuels must be used when the pulp mill process is restarted after a shutdown or disruption. At the Äänekoski bioproduct mill, bio-based pitch oil is used in these situations. It is one of the components of tall oil. Tall oil is produced as a by-product of pulp production. The aim is to create a total concept for bio-based start- up fuels that can be used at all Metsä Fibre pulp mills. “The solutions are based on existing technology. The start-up fuel for the Rauma and Joutseno mills will also be non-fossil-based by 2030,” says Pehu-Lehtonen. Metsä Fibre’s sawmills will switch from fossil fuels in stages by the end of this decade. “We will make an overall plan for the transition to bio-based fuel oils to decide how best to implement the change of fuels. Technically this is completely achieva- ble,” Pehu-Lehtonen says. •
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