EP 2707539 A1 20140319 - COMPACT PROCESS FOR PRODUCING PREHYDROLYZED PULP
Title (en)
COMPACT PROCESS FOR PRODUCING PREHYDROLYZED PULP
Title (de)
KOMPAKTES VERFAHREN ZUR HERSTELLUNG VON VORHYDROLYSIERTEM ZELLSTOFF
Title (fr)
PROCÉDÉ COMPACT D'OBTENTION DE PÂTE PRÉALABLEMENT HYDROLYSÉE
Publication
Application
Priority
SE 2011050610 W 20110513
Abstract (en)
[origin: WO2012158075A1] The invention is related to an improved compact process for producing dissolving pulp in a prehydrolysis kraft cooking process. In order to avoid pitch problems with blocked withdrawal screens and to obtain a distinct ending of the prehydrolysis stage, as well as a thorough alkaline impregnation ahead of the kraft cook stage, alkali is charged to the mixture of prehydrolyzed material to such an extent that the residual alkali concentration after neutralization of the acidic hydrolysate is above 20 g/l EA as NaOH and the temperature of the resulting alkaline treatment liquor for the prehydrolyzed material is lowered by at least 10% in comparison to the temperature in the prehydrolysis stage. The alkali charge will avoid redeposition of hemicelluloses dissolved in the prehydrolyse stage and will abruptly swing the wood material mixture to alkaline conditions favourable for a alkali impregnation stage at reduced temperature ahead of the final kraft cooking stage, which impregnation stage will extract the major part of the hemicelluloses content of the cellulose material.
IPC 8 full level
D21C 1/02 (2006.01); D21C 1/04 (2006.01); D21C 1/06 (2006.01); D21C 3/02 (2006.01); D21C 3/26 (2006.01)
CPC (source: EP)
D21C 1/02 (2013.01); D21C 1/04 (2013.01); D21C 1/06 (2013.01); D21C 3/02 (2013.01); D21C 3/26 (2013.01)
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
DOCDB simple family (publication)
WO 2012158075 A1 20121122; CA 2837277 A1 20121122; CA 2837277 C 20170627; CN 103687990 A 20140326; CN 103687990 B 20160330; EP 2707539 A1 20140319; EP 2707539 A4 20141119; EP 2707539 B1 20190508; ES 2737432 T3 20200114; PT 2707539 T 20190627; RU 2546497 C1 20150410
DOCDB simple family (application)
SE 2011050610 W 20110513; CA 2837277 A 20110513; CN 201180072257 A 20110513; EP 11865841 A 20110513; ES 11865841 T 20110513; PT 11865841 T 20110513; RU 2013155475 A 20110513