SCA R&D Centre normally supports SCA’s paper mills in their efforts to improve manufacturing processes and products. Since the growth rate in the demand for publication paper is falling all over the world, SCA R&D Centre is also working to a large extent on alternative applications for SCA’s wood raw products.
Many benefits
Not only do trees have desirable wood fibre, they also have various extractive substances such as what we usually refer to as “resin”.
These substances have no purpose in pulp and paper making; in fact they are a nuisance. But removing these extractive substances from the process would have many benefits.
“The extractive substances surround the wood fibres like soap and are one of the reasons why so much energy is required to produce pulp. If we could remove half of the extractive substances, energy needs would fall by about 15%,” says Bengt Wikman, Head of Chemical and Mechanical Pulp at SCA R&D Centre, and adds:
“Paper properties and runnability in the paper machines would also improve if we could reduce the extractive substances in the pulp.”
The new challenge for researchers lies in finding suitable methods for removing the extractive substances from the wood.
“We want to know whether it’s better to remove the extractive substances before the first stage of refinement, where the wood chips are converted to pulp, or whether it’s better to do it later,” says Birgitta Engberg, Project Manager for research into the extractive substances.
Birgitta is employed at Mid Sweden University, but works part time at SCA R&D Centre.
New products
If it was possible to separate the extractive substances from the wood fibres effectively, they could also be used as raw materials in soap, adhesives or impregnating agents. But there is a lot of work remaining before we can speak about specific products.
If we could remove half of the extractive substances, energy needs would fall by about 15%.
“First of all we need an efficient method for separating the extractive substances from the process water. Only then can we decide what products might apply,” says Marie Eriksson, Head of Sustainable Chemistry, and adds:
“We also have to look at the potential for removing the extractive substances. What would it cost, and what are the benefits? One alternative could be to use them as fuel – extractive substances have a very high energy value.”
There are other interesting substances in wood besides extractive substances. One of them is hemicellulose.
“Here at SCA, we do not conduct any research into converting hemicellulose to bioethanol by fermentation, which has received a great deal of focus in the US. We are more interested in using hemicellulose as a paper chemical, or for the manufacture of barriers. A recent trend all over the world is trying to find new and more efficient methods for utilising existing raw materials,” concludes Marie.