Method for continuous cooking of lignocellulosic fiber material
US6468390B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1998 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Aug 24, 2018 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/005
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method for continuous cooking of lignocellulosic fiber material, comprising the steps of sequentially (a) in a first stage, impregnating the fiber material in an impregnation liquid comprising alkali metal hydroxide, and thereafter withdrawing (14, 514) a spent impregnation liquid; (b) in a second stage, cooking the fiber material in a cooking liquor comprising alkali metal hydroxide; and (c) in a third stage, adding (A), to said fiber material, a liquid which is rich in hemicellulose, said liquid preferably comprising at least a part (14a, 514a) of said withdrawn spent impregnation liquid. In a fourth stage (d), the fiber material is cooked in a cooking liquor comprising the liquid added in the third stage, whereby the fiber material is subjected to a retention time of at least 1 hour in said fourth stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.