EP 0135461 B1 19870429 - BATCH DIGESTER MULTI-STAGE PULPING PROCESS
Title (en)
BATCH DIGESTER MULTI-STAGE PULPING PROCESS
Publication
Application
Priority
US 52612183 A 19830824
Abstract (en)
[origin: EP0135461A1] The multi-stage pulping process is performed in a single digester (10) in a batch type operation. The wood chips to be cooked are introduced into the digester (10) and soaked with a warm black liquor to remove most of the air from the digester (10) and the chips. This warm black liquor is thereafter displaced from the digester (10) with a mixture of a first stage hot black liquor and hot white liquor, the proportionate amount of hot white liquor being relatively high. The temperature of the digester contents is then raised to a cooking temperature for a predetermined amount of time. The original cooking liquor is then displaced with a mixture of a second hot black liquor and hot white liquor, the proportionate amount of hot white liquor in this second cooking liquor being less than in the first. Again, the temperature of the digester (10) is raised to a cooking temperature and the cooking is carried out for a shorter period of time than in the first cooking stage. After the required number of cooks which may be preferably three but may be as low as two or more than three, the cooking liquor is displaced from the digester with a liquid filtrate (47) derived from pulp washing. Finally, the contents of the digester (10) are emptied by applying gas under pressure to the interior of the digester (10).
IPC 1-7
IPC 8 full level
CPC (source: EP KR)
D21C 3/26 (2013.01 - KR); D21C 3/266 (2013.01 - EP)
Designated contracting state (EPC)
DE FR GB IT SE
DOCDB simple family (publication)
EP 0135461 A1 19850327; EP 0135461 B1 19870429; BR 8404040 A 19850716; CA 1255948 A 19890620; DE 135461 T1 19860213; DE 3463401 D1 19870604; ES 535377 A0 19850716; ES 8506367 A1 19850716; FI 80085 B 19891229; FI 80085 C 19900410; FI 843183 A0 19840813; FI 843183 A 19850225; IN 160869 B 19870808; JP S6059189 A 19850405; KR 850001816 A 19850401; KR 860001615 B1 19861014; MX 167934 B 19930422; PH 23991 A 19900209; SU 1454262 A3 19890123
DOCDB simple family (application)
EP 84630112 A 19840803; BR 8404040 A 19840813; CA 460156 A 19840801; DE 3463401 T 19840803; DE 84630112 T 19840803; ES 535377 A 19840823; FI 843183 A 19840813; IN 561CA1984 A 19840810; JP 15947584 A 19840731; KR 840004969 A 19840817; MX 20246484 A 19840822; PH 31115 A 19840817; SU 3781689 A 19840823