Extractives in the Scandinavian pulp and paperindustry : Current and possible future applications

The forest industry is one of Sweden’s most important business sectors. Thanks to its biobased rawmaterials and products, the forest industry plays a key role in the development towards asustainable, circular economy. To meet market needs, and to drive the growth of the circulareconomy, the forest industry is continually developing its processes and products. It is seeking to useits raw material, the forest, as efficiently as possible and is constantly seeking to improve quality andincorporate new functions into materials and products.Pulp and paper makes up the largest part of the forest industry, followed by sawn wood productsand products made from paper and paperboard. 3.9 million tons of pulp and 10.1 million tons ofpaper were produced in Sweden in 2016.The pulp and paper industry uses stem wood as its raw material. Stem wood consists of cellulose,hemicellulose, lignin, and extractives. Cellulose and hemicellulose are separated in the pulpingprocess and the economically most important components in wood. Lignin and extractives areusually burned to provide the mill with heat and power, but the use/needs has changed over timedue to development of more energy efficient mills. Today lignin is extracted from the black liquor forexternal use, while extractives are fractionated and used for production of a wide range of productssuch as, biodiesel, adhesives, and chemical intermediates.The extractives make up between 3 and 5 weight-% of the wood and consists of a wide range ofcompounds. The majority of those compounds are fatty acids such as oleic- and linoleic acid androsin acids, such as abietic- and pimaric acid. The remaining compounds are commonly referred to as“neutrals” and are dominated by β-sitosterol. The extractives in Scots pine for example, consist of 70% fatty acids, 20 % rosin acids and 5 % neutrals.Today, the extractives are separated at the pulp and paper mills during the regeneration of cookingchemicals into a product called crude tall oil (CTO). 2.5 million metric tons of CTO is producedglobally with 80% of the production situated in North America and Scandinavia. 1.3 million tons isproduced in North America and 600 000 tons is produced in Scandinavia. 2.0 million metric tons iscurrently refined globally, while the rest is used internally by the mills for the production of heat andpower.CTO is currently refined into a range of products which can be divided up into (i) chemicalintermediates, (ii) biodiesel, and (iii) tall oil pitch. The chemical intermediates are mostly used for theproduction of adhesives, while the biodiesel is used as a transport fuel, and the tall oil pitch is usedfor production of heat and power.To meet market needs, and to drive the growth of the circular economy, extractives could potentiallybe used for the production of other products, either through new refinement routes of CTO or novelextraction and separation methods from the raw material. In order to identify opportunities for theproduction of other extractives based products, the extractives value chain must first be mapped.Second, refinement routes as well as extraction and separation methods suitable for isolation andprocessing of valuable compounds must be identified.Report produced by Processum within the Interreg project Bioraff Botnia