(19)
(11) EP 1 932 967 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
15.07.2009 Bulletin 2009/29

(43) Date of publication A2:
18.06.2008 Bulletin 2008/25

(21) Application number: 07446011.4

(22) Date of filing: 07.12.2007
(51) International Patent Classification (IPC): 
D21C 3/00(2006.01)
D21C 7/00(2006.01)
D21C 7/14(2006.01)
 D21C 3/22(2006.01)
D21C 1/00(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR
Designated Extension States:
AL BA HR MK RS

(30) Priority: 13.12.2006 SE 0602675

(71) Applicant: Metso Fiber Karlstad AB
651 15 Karlstad (SE)

(72) Inventor:
  • Snekkenes, Vidar
    NO-0682, OSLO (NO)

   


(54) A method for producing cellulose pulp in a continuous digester in an energy-efficient manner


(57) The invention describes a method for producing cellulose pulp in a continuous digestion system in an energy-efficient manner. Cellulose chips are fed continuously with a transfer liquid in a transfer line (11) to a top separator (20) arranged at the top of a digester (30), for the separation of free liquid from the cellulose chips. The top separator has a withdrawal space (21) in which free liquid collects. At least a fraction of the free liquid that has separated, with a temperature Tut, is led in a return line (32) from the withdrawal space of the top separator to a position to be used as transfer liquid. At least one pressurised withdrawal of black liquor is carried out in the digester (30) essentially at the cooking temperature of at least 135 °C. The invention is characterised in that an additive liquid with a temperature Tin is added at the withdrawal space (21) of the top separator, where Tin>Tut.







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