Lignin valorisation

‘You can do anything with it, except make money.’ Until very recently, this is how the industry looked at lignin. But times are changing. Lignin has developed from a residue that was only useful as a fuel for producing cellulose into a sustainable and very satisfactory alternative to fossil fuels. You can even use it to make vanilla.

Lignin as raw material for the chemical industry

We are forcing the oil-based economy back a step

Lignin is a natural adhesive that gives trees (as well as grasses and straw) their strength and flexibility. On average, trees are twenty-five percent lignin. Richard Gosselink, researcher at Wageningen UR Food & Biobased Research, has been studying this wood substance for fifteen years. Seen as the lignin expert in the Netherlands, he recently wrote his thesis on the subject. His conclusion: this substance can potentially be used for countless economically-viable applications.

Alternative

At present, 98 percent of lignin is treated as a residue and burnt in the process of producing cellulose from wood for the production of paper and cardboard. Lignin is also released when cellulose-ethanol is made from biomass, and it is commonly used as an adhesive in cement. But according to Gosselink, lignin is also a perfect alternative for synthetic adhesives, in fibreboard for example. ‘Synthetic adhesives are made from crude oil. And certain components, such as formaldehyde, are highly toxic. This substance is on the list of extremely carcinogenic substances in the US. We want to stop using it, but first we need a viable alternative. And lignin fits the bill perfectly.’

Purification

Lignin is already capable of replacing some thirty percent of the fossil raw materials in adhesives. Gosselink thinks that it will take another two to three years before adhesives can be produced on a totally organic basis. ‘The change-over could be very quick, particularly if formaldehyde appears on the global list of banned substances.’ Lignin can also be used as a component for producing polymers. Gosselink: ‘In certain conditions, you can break lignin down into monomers, which can be used as components in all kinds of plastics, such as foam, resin and coatings. In order to make lignin an economically-viable raw material, it needs to be purified via a refinery process so that we can break the substance down into chemical building bricks for the industry. You can make polycarbonate, for example, which is one of the materials used for making CDs. Lignin can also be used to make aromatic chemicals used in the production of flavourings such as vanilla. This is already happening on a commercial basis in Norway.’

LignoValue

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Some of the research into lignin as a chemical raw material is being carried out within the LignoValue project, a consortium of knowledge institutes and chemical companies. Wageningen UR plays a coordinating role in the consortium and is responsible for much of the laboratory research. The research findings on the use of lignin as a raw material for the chemical sector are promising. Gosselink is hopeful about the prospects of follow-up research, which he thinks sorely needed. There is no doubt that lignin is arousing interest in the industry. ‘It’s a hot item. It’s even more obvious to us now we’ve launched the Wageningen UR Lignin Platform. The room is packed for every meeting. The industry wants to exploit its residue flows, as it they know that this is money thrown away. This, combined with the fact that the price of fossil raw materials is rising, means that raw materials from biomass will soon be able to compete in terms of price. And the technology for capitalising on lignin is becoming more and more advanced. I predict that lignin will become a serious raw material for the chemical industry within five to ten years. So the oil-based economy is being forced back a step in favour of the biobased economy.’

This customers' story was published in the Food & Biobased News letter - January 2012