Process for oxygen bleaching using two vertical reactors
US5217575A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1992 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Mar 24, 2012 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C9/1026
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process for oxygen bleaching fibrous cellulose pulp is described in which the pulp passes a first delignification zone with a predetermined low temperature and a second delignification zone with a predetermined high temperature which is higher than that in the first delignification zone. The pulp is fed through a first vertical reactor containing said first delignification zone with low temperature, and thereafter through a second vertical reactor containing said second delignification zone with high temperature. The temperature in the first delignification zone is either maintained at the temperature that the pulp entering for bleaching has acquired during a previous treatment before the oxygen bleaching, or as required is adjusted by the controlled supply of steam to a mixer disposed in the pipe before the first reactor. The temperature in the second delignification zone is adjusted by the controlled supply of steam to a mixer disposed in the pipe between the two reactors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.