Research: The new side of Lignin
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?
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?
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?
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?
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 trans formation 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?
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 emer gence of new services around the basic materials we provide to our customers.
How does SE actively promote trend-setting developments in the ﬁber industry?
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?
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.
Picture credits: Siemens AG
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