LENZING/CLOQUET, Minn. — January 13, 2013 —Since May 28, 2013, the South African pulp and paper group, Sappi has been producing viscose pulp in the USA, using the state-of-the-art VISCBC cooking process patented by Lenzing Technik. For this purpose, the Cloquet plant, originally producing pulp for the paper industry, had to be converted to produce viscose pulp. About EUR 130 million have been invested in this future-oriented project, ensuring the continuity of the site for the long term. In the process, Sappi contracted technology and engineering expertise for the key areas of digester and fiber line from Lenzing Technik GmbH. Despite an excessively long, record cold winter, this ensured a timely start-up and the accurate adherence to desired excellent quality parameters. Figuratively speaking at the push of the button, Sappi now produces around 330,000 t of viscose pulp per year in Cloquet.
With temperatures lower than –30 °C and snowfall until May 15, the 2012-2013 winter will go down in the annals of history in Minnesota. In order to make sure that the start-up of the entirely rebuilt pulp mill scheduled for May would be successful, a Lenzing Technik core team had moved from Austria to Cloquet for six months. “The excellent cooperation between our colleagues and the team from Lenzing Technik has laid the foundation for this overwhelmingly successful project,” emphasizes Mike Schultz, Managing Director, Cloquet Mill, Sappi Fine Paper North America.
“Hybrid Pulp Mill” For Paper And Viscose
To be able to respond appropriately to market conditions worldwide, the site was upgraded to what may be called a “hybrid mill”. From now on, the production of viscose pulp as well as of paper pulp is possible. Before starting paper pulp production on May 5, the so-called water run had to be carried out. Six kilometers of pipe work and tanks with a total volume of 5,000 m3 had to be cleaned and checked for leaks. “In order to meet the stringent timetable, works on the plant had to be meticulously scheduled,” declares Herbert Hummer, Managing Director of Lenzing Technik GmbH. “Just to give you an idea, during the water runs in the first sections of the plant, welding was still underway in the subsequent areas.”
After the start-up of paper pulp production went smoothly and the plant had delivered excellent quality and volumes right from the start, it was put to a real test on May 28: “Right before starting up the digester and the fiber line for viscose pulp production, the anticipation was tangible both at Sappi and with our team,” recalls Project Manager Berndt Cupak. In fact, the viscose pulp produced according to the Viscose Continuous Batch Cooking (VISCBC) process delivered the requested premium quality, and after a few days the plant had almost achieved the volume target. “Our plant in Cloquet is now equipped with state-of-the-art technology and, being the first viscose pulp mill of the Sappi Group in the USA, holds a pioneering position, thus ensuring the continuity of the site for the long term,” emphasizes Mike Schultz.
Tankfarm to VISCBC cooking process at Sappi Cloquet
Posted February 3, 2014