The traditional pulp-making process uses around 50% of the tree. The rest, such as lignin and hemicellulose, is often burned for energy. Using wood more efficiently to create new, marketable products beyond pulp has become a priority for the pulp and paper industry. At Stora Enso, we are trying to extract hemicellulose, sugars and lignin from biomass more efficiently with new technologies. Lignin is already commercially produced by Stora Enso and has a range of applications.
What is lignin?
Trees are made from three polymeric carbohydrates: cellulose, hemicellulose and lignin. Traditionally, the pulp industry has discarded lignin when creating paper and packaging and lignin is often used as a energy source for pulp mills. There are many varieties of lignin, which vary according to the extraction process.
Lignin is not a ‘one-size-fits-all’ product as different types of lignin vary considerably in performance. It is often presumed that lignin has numerous applications but limited business opportunities. However, lignin can be used as a replacement for fossil-based materials, which is crucial for the bio-based industries. Lignin produced through Stora Enso’s biorefinery concept also differs from common, kraft lignin and opens up new application opportunities in the construction and automotive industries, among others.
Where can lignin be used?
There are many potential markets and applications where lignin can replace fossil-based materials. Refined lignin can be a replacement for oil-based phenolic materials which are used in resins for adhesives e.g. in plywood and veneer applications. Lignin’s structure is highly aromatic, which means it can be used where rigid structures are preferred, although in some cases, challenges remain due to its dark colour.
How is lignin produced at Stora Enso?
The Sunila Mill in Finland is the world’s first integrated lignin extraction plant which produces dry kraft lignin. By using different biomass fractions to produce lignin, the mill’s resource efficiency has greatly improved. Lignin production has helped the mill to replace fossil fuels and, to reduce its CO2 emissions by 27,000 tonnes/year. A new target aims to further decrease emissions, which should be possible after some modifications to the mill are made.Like all of our products, lignin is made from sustainably sourced wood. Sunila Mill has both FSC and PEFC chain-of-custody certification.
Any questions? Contact our application team.