Global Patent Index - EP 0445321 B1

EP 0445321 B1 19940601 - Process for making pulp in a continuous digester.

Title (en)

Process for making pulp in a continuous digester.

Title (de)

Verfahren zur Herstellung von Zellstoff in einem kontinuierlichen Kocher.

Title (fr)

Procédé de fabrication de pâte dans un lessiveur en continu.

Publication

EP 0445321 B1 19940601 (DE)

Application

EP 90104231 A 19900305

Priority

EP 90104231 A 19900305

Abstract (en)

[origin: EP0445321A1] A desired pulp quality is specified using a quality coefficient (Q<*>). Suitable quality coefficients are, inter alia, the yield (Y) or the residual lignin concentration (kappa number) of the pulp. A process module (M) is used to determine the digestion temperature (T<*>) associated with the specified value of the quality coefficient (Q<*>) as the main control variable. This takes account of the actual values of the concentration of chemicals (C), the digester filling level (L), the production quantity (n) and technology-dependent process constants (a, k, E). The process model can be adapted to match it to altered operating conditions in the pulp digester. For this purpose, at least one of the process constants (k) is redetermined. The actual value of the yield (Y), which is used as quality coefficient, is preferably simulated at least using a spent liquor analysis. Other quantities used for the simulation may be, in particular, the hydromodule (Xa) or the rotary speed of the wood feed means (n1, n2, n3). <IMAGE>

IPC 1-7

D21C 3/22; D21C 3/24

IPC 8 full level

D21C 3/22 (2006.01); D21C 3/24 (2006.01)

CPC (source: EP)

D21C 3/228 (2013.01); D21C 3/24 (2013.01)

Designated contracting state (EPC)

AT DE ES FR IT SE

DOCDB simple family (publication)

EP 0445321 A1 19910911; EP 0445321 B1 19940601; AT E106477 T1 19940615; DE 59005944 D1 19940707

DOCDB simple family (application)

EP 90104231 A 19900305; AT 90104231 T 19900305; DE 59005944 T 19900305