公开(公告)号：EP0909354A1

公开(公告)日：1999-04-21

申请号：EP97930929.0

申请日：1997-06-16

申请人： SUNDS DEFIBRATOR INDUSTRIES AB

发明人： BOMAN, Rolf ,  BOKSTRÖM, Monica ,  GERMGARD, Ulf ,  MELLANDER, Pia ,  NORDEN, Solveig ,  SUNDIN, Matts

IPC分类号： D21C9

CPC分类号： D21C9/1026 ,  D21C9/144

摘要： The present invention relates to a multi-stage paper pulp bleaching process in which at least one of the bleaching stages is carried out in a reactor with chlorine dioxide at a pulp concentration of 8-40 %. The pulp is bleached with chlorine dioxide in a pressurized vessel at an overpressure of 0.1-10 bars and at a temperature of between 90-110 °C and for a reaction time of 1-90 minutes. The pressure of the pulp is lowered in a downstream tower in a manner such as to also lower the temperature of the pulp and enable residues of chlorine dioxide to be extracted in gas phase.