公开(公告)号：EP2707539A4

公开(公告)日：2014-11-19

申请号：EP11865841

申请日：2011-05-13

申请人： VALMET AKTIEBOLAG

发明人： TROLIN DANIEL ,  ANTONSSON STEFAN ,  SAETHERÅSEN JONAS ,  LINDSTRÖM MIKAEL

IPC分类号： D21C1/02 ,  D21C1/04 ,  D21C1/06 ,  D21C3/02 ,  D21C3/26

CPC分类号： D21C1/02 ,  D21C1/04 ,  D21C1/06 ,  D21C3/02 ,  D21C3/26

摘要： 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.

公开(公告)号：EP2609248A4

公开(公告)日：2014-09-03

申请号：EP10856491

申请日：2010-08-25

申请人： VALMET AKTIEBOLAG

发明人： TROLIN DANIEL ,  FURHEM HANS

IPC分类号： D21C1/02 ,  D21C1/06

CPC分类号： D21C1/06 ,  D21C1/02