Method of continuous pulping in a digester with high black liquor usage in the impregnation stage
US5925216A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Aug 5, 2017 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C7/14
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The present invention provides a method for continuously cooking kraft pulp in a digester having the steps of: PA1 feeding chips into an inlet of a digester; PA1 supplying black liquor to an impregnation zone of the digester in an amount such that the black liquor makes up greater than 40% by volume of the total volume of liquid present in the impregnation zone; PA1 extracting liquor from a screen girdle downstream of where the black liquor is added to the digester, in the direction the wood chips flow through the digester, in an amount greater than 50% by volume of the total volume of liquor present at the location of the screen girdle; PA1 maintaining a liquor:wood ratio in the impregnation zone of greater than 3:1; and PA1 discharging cooked pulp from the digester.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.