Oxygen delignification of wood pulp
US4198266A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1977 |
| Grant date | Apr 15, 1980 |
| Priority date | — |
| Expiry date | Oct 12, 1997 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/1068
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
In a process for delignifying wood pulp with oxygen, a pulp slurry and oxygen are introduced into an elongated reactor having a plurality of gravitational fall zones at which oxygen is dissolved in the liquid phase of the slurry. The length of the reactor is sufficient to provide the residence time required for delignification reactions. Alkali is added in controlled quantities along the reactor length in response to sensed slurry pH to maintain a predetermined slurry pH throughout the reactor. The oxygen treated slurry discharged from the reactor is separated into pulp and hot recycle liquor, the latter being utilized to effect thermal, chemical and water economies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.