Raw materials, energy and water are used as efficiently as possible. Every part of wood is used for the purpose for which it is best suited – logs are delivered to sawmills, pulpwood is used for pulp, other bioproducts and further processing, and branches, treetops and bark are used to generate bioenergy. The chips produced as a by-product of sawing are used in Metsä Fibre’s pulp production.
Logs arriving at our sawmills are already optimally cut in the forest from the perspective of customer needs and the end products. This ensures that the end products are of a high quality, and that not even a splinter of this valuable raw material is wasted.
A unique bioproduct mill concept
The bioproduct mill concept developed by Metsä Fibre enables the future expansion of the product range with new bioproducts that provide an increasingly high added value. In the bioproduct mill concept, the wood raw material and production side streams are used in the form of various bioproducts, which can replace fossil-based materials and fossil fuels.
Resource wisdom is also implemented through cooperation with business partners. In an industrial ecosystem, different operators produce different end products using their own expertise.
In December 2020, Metsä Group’s innovation company Metsä Spring and Valmet started building a pilot plant for a 3D fibre product in the Äänekoski mill area. The pilot plant will be used for testing and developing a manufacturing method for a new type of packaging solution. The plant’s pilot production line will produce ready-made 3D fibre products from wood fibre to replace packaging made of plastic and aluminium.
The same ecosystem also includes the pilot plant of MI Demo Oy, a joint venture of Metsä Spring and Itochu Corporation. It produces textile fibres from pulp.
In collaboration with Veolia, Metsä Fibre has also investigated the purification of raw methanol created in the pulp production process into commercial biomethanol. As part of this partnership, Veolia is planning to build a raw methanol processing plant in connection with the Äänekoski bioproduct mill.
Metsä Fibre’s own resource efficiency has also been improved through new bioproduct solutions. At the Äänekoski bioproduct mill, the production of sulphuric acid from the mill’s odorous gases has expanded the mill’s closed chemicals cycle. It also minimises any sulphate discharges into the waterways. The same technology would be used at the planned Kemi bioproduct mill.
Metsä Fibre’s Joutseno mill and the company’s bioproduct mill in Äänekoski both produce product gas from bark. This product gas is used as a fossil-free fuel in the mills’ own processes. The planned Kemi bioproduct mill would also have a similar gasification plant. Our goal is that in the future, all of our mills will operate completely without fossil fuels.
Making use of a challenging waste fraction
As part of Metsä Group, Metsä Fibre aims to utilise 100 per cent of all production side streams. Currently, Metsä Fibre is using 83 per cent of its side streams. A major reason for this utilisation rate is green liquor dregs.
Green liquor dregs are a fraction created during chemical recovery for which there has been no established use thus far. As a concrete example of research into the utilisation of green liquor dregs, a test field was constructed at the Äänekoski bioproduct mill in the autumn of 2020 in which green liquor dregs and ash were used in the structure. The environmental impact of green liquor dregs and the durability of the created structure will be monitored at Äänekoski over the next two years.
If found technically suitable and environmentally acceptable, green liquor dregs could be used to replace virgin raw materials such as crushed rock and gravel in field structures to save natural resources.