Pretreatment of chips with white liquor prior to a treatment with black liquor: Förbehandling av flis med färsk vitlut före behandling med svartlut
2001 (Swedish)Patent (Other (popular science, discussion, etc.))
The invention concerns a method for the manufacture of cooked cellulose pulp in which the starting material, preferably chips, undergoes a successive increase in temperature towards cooking temperature while the chips are first treated in a pre-treatment zone in which the main part, greater than 50%, of fresh white liquor necessary for the cooking stage is added, after which this alkali-rich treatment fluid is withdrawn and replaced to a major extent by black liquor. The alkali-rich treatment fluid that has been withdrawn after the pre-treatment to stage is then added to the cooking stage, which is why the addition of fresh white liquor to the cooking stage is reduced to an equivalent amount. Maximal yield-enhancing effect is obtained using polysulphide-rich white liquor during the pre-treatment at a temperature in the interval 60 +- 40 DEG C and retention time in the interval 2-60 minutes, preferably 2-10 minutes.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:kth:diva-49236OAI: oai:DiVA.org:kth-49236DiVA: diva2:459423
SE 518538 (2002-10-22)
US 7270725-B2 (2007-09-18); JP 4280636-B2 (2009-06-17); EP 1458927-B1 (2010-04-08); BR 0214922-B1 (2012-12-11)2011-11-252011-11-252013-08-09Bibliographically approved