Sappi Fine Paper is using black liquor, a residue from the pulping process, to generate energy equivalent to 100,000 barrels of fuel oil.
The company’s North American operations have instituted a $36 million capital improvement project to upgrade evaporators and a recovery boiler at its Somerset Mill in Skowhegan, Maine. The boiler is now able to recover more black liquor, which Sappi says is a renewable, carbon-neutral fuel.
When the black liquor is fired in the recovery boiler, cooking chemicals are removed and steam is generated. This is used throughout the mill’s operations. “In short, the more black liquor that we can process and burn, the less fossil fuel we need to support the mill,” Sappi says.
Two other by-products that the company has found use for are bottom ash and fly ash. At its Cloquet Mill in Minnesota, Sappi is now diverting these pulp and paper manufacturing residues from landfills and giving them to farmers, through a partnership with the University of Minnesota Extension Service, Carlton County By-Products Program.
The ash’s alkaline nature helps improve soils for growing alfalfa, which is then turned into hay for cows. As well as providing the ash, Sappi also pays for the hauling and spreading of the material. The company distributes between 25,000 and 30,000 tons of ash in the Cloquet area each year, saving farmers over $1 million a year.
This program and others reduced the Cloquet Mill’s landfill volume by 75 percent between 2004 and 2009, Sappi says.
Sappi Fine Paper North America, a division of the NYSE-listed Sappi Limited, is a Boston-based company producing coated paper for use in premium magazines, catalogues, books and high-end print advertising. Its brand names include McCoy, Opus, Somerset and Flo.
Its mills are triple chain of custody certified to Forest Stewardship Council (FSC), Sustainable Forestry Initiative (SFI), and Programme for the Endorsement of Forest Certification (PEFC) standards.
Over 80 percent of the energy used by Sappi's North American mills comes from renewable resources, resulting in one of the lowest carbon footprints of any major North American coated paper supplier, the company says.
Recently €8.9 billion ($12.5 billion) Finnish paper and lumber company UPM announced that it has cut its electricity and heat consumption by about nine percent per paper ton in the past two years. The company generates all the heat and one third of the electricity it needs for paper-making from combined heat and power plants operating on its paper mill sites.