Continuous digester with a low temperature gas-phase
US5882477A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Feb 10, 2017 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C7/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A cellulose pulp continuous digester (e.g. for producing kraft pulp) is operated so that it has the advantages of a hydraulic digester yet has a gas-filled zone over the liquid level. A slurry of chips and cooking liquor is introduced into the top of the digester vessel through an inverted top separator. A liquid level is established below the inverted top separator, and a chips level is established below the inverted top separator (above or below the liquid level). A gas-filled zone above the liquid level includes compressed gas, and is at a temperature of less than 160 (preferably less than 120).degree.C. and at a pressure of between 50-200 (preferably 80-150) psig. The chips are heated by recirculating and heating liquid using a recirculation loop below the chips level, and a countercurrent flow zone is preferably provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.