The first commercial lignin separation plant in Europe has been handed over to global forest industry major Stora Enso. Supplied by Finland-based pulp and energy industry technology major Valmet, the “LignoBoost” unit, which includes a lignin dryer, is installed at Stora Enso’s Sunila pulp mill in Finland. Integrated with the 370 000 tonne-per-annum pulp mill the unit separates, collects and drys lignin from the black liquor. The plant has been running since January 2015 with production ramp up during the year.
– Through the lignin extraction process we have replaced a great amount of natural gas with the dried lignin produced, thus reduced our carbon dioxide emissions. We are developing this new product and working together with our customers to start external sales, said Sakari Eloranta, Senior Vice President, Operations and Investment Projects, Stora Enso Biomaterials.
The investment is seen as a significant step in transforming the pulp mill into an innovative and customer-focused biorefinery.
Originally developed in Sweden by Chalmers University of Technology together with Innventia, an applied forest industry R&D company that also operates a demonstration facility at Bäckhammar pulp mill in Sweden, the patented process, by which lignin is extracted from the spent cooking chemicals (black liquor) in kraft pulp process, is owned by Valmet. By treating the black liquor with carbon dioxide and a strong acid, the lignin is precipitated then washed and dried. Lignin is an organic polymer and has a heating value similar to carbon. Along with cellulose and hemi-cellulose, lignin is the most common material in wood.
The world’s first commercial-scale unit was installed in 2014 in the US at a pulp and paper mill owned by Domtar in Plymouth, North Carolina. Apart from fuel, lignin has a number of potential applications such as antioxidants, binders and dispersants.