Lignin is seen as undesirable in paper production because it contributes to paper yellowing. To avoid this, considerable chemical effort is required to dissolve it out of wood. However, lignin is one of the most mechanically- and chemically-resistant polymers, and has highly interesting properties.
Stora Enso has been conducting research into lignin for 15 years. We spoke to Mikael Hannus, vice president of the Group R&D Innovation at Stora Enso about this.
Lignin is the second most abundant organic polymer on earth, exceeded only by cellulose. It is an organic substance which causes lignification of a cell when embedded into the cell wall of a plant. The content of lignin is higher in coniferous trees than in deciduous trees and it ensures high compressive and tensile strength in wood. Researchers at Stora Enso (SE) regard lignin as a challenging and complex material with application opportunities in the construction and automobile industries.
Mr. Hannus, please introduce yourself and provide us with a little information about your role within SE.
Mikael Hannus: I’m a pulping technology engineer with the most exciting job at Stora Enso – driving collaboration with our partner universities as well as a number of other interactions around R&D.
You have been researching and examining lignin and its value for the fiber industry for several years now – could you give us an insight into your work and the particular challenges of this complex substance?
Mikael Hannus: Our approach is to find the best fit between the natural structure of lignin, the processes we use to extract and separate lignin from wood, and, of course, the applications for which our customers use this complex structure of natural aromatics.
Lignin is the second most abundant organic material on earth. However, it is far from desirable in paper production because it contributes to paper yellowing. To avoid this, great chemical effort is required to dissolve it out of wood. Do you think the significance of lignin as a raw material for the fiber industry has been previously underestimated and what role will it play in the future?
Mikael Hannus: Actually, many forest-based products utilize the benefits of lignin – in addition to all solid wood products, we want to use some of the properties of lignin in magazine papers, fiber-based packaging grades, and in new materials or chemicals. What is often overlooked is the fact that the chemical recovery cycle of a kraft mill requires reaction conditions as a result of which 70% – 80% of the lignin released from the wood needs to be burned to achieve the high temperature chemical regeneration – of course, that heat is recovered as steam for power and heat supply to the mill and associated energy markets.
What is the value of lignin for the fiber industry and how can it be utilized?
Mikael Hannus: It is important to remember that there are many types of lignin – each with very different properties, uses, and values. It is only possible to valorize lignins that are fairly clean and well defined. The value lies in the aromatic structure, reactive groups in the structure, and the size of the natural aromatic molecule.
How do you see the fiber industry developing and how will SE realign with these developments in order to stay ahead in the future?
Mikael Hannus: The demand for fiber has seen a healthy growth and we expect this to continue thanks to global megatrends and the need for sustainable solutions in construction, packaging, hygiene, special chemistry, and the textile industry. We are currently undergoing a transformation in which the declining share of printing paper business is being replaced by a growth in fiber-based packaging and cellulose fibers for special applications within the hygiene and textile industries.
What trends, innovations, and topics do you think will determine the future of the fiber industry in the next 20 years?
Mikael Hannus: Making more from less – meaning steady progress in resource efficiency, high recycling rates, new material properties that reduce the need for fossil-based materials, as well as the emergence of new services around the basic materials we provide to our customers.
How does SE actively promote trend-setting developments in the fiber industry?
Mikael Hannus: We invest a lot in R&D and the whole organization is driven by innovation.
How is Siemens establishing itself as a partner of trust in times of changing markets?
Mikael Hannus: Siemens is providing an enormous amount of specialized knowledge in relation to our production assets and related services, as well as long-term collaboration to capture the existing and future opportunities offered by biobased materials.