Maintenance of sulfur concentration in Kraft pulp processes
US8246779B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2010 |
| Grant date | Aug 21, 2012 |
| Priority date | — |
| Expiry date | Nov 12, 2030 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/0035
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Methods and apparatus for maintaining sulfur concentration in the chemical recovery cycle of a Kraft pulping process. A portion of the recovery boiler ash is dissolved, treated to remove solids, and combined with an acid to provide a solution. The recovery boiler ash may be dissolved directly in the acid. The acid may be effluent from a chlorine dioxide generator. The resulting solution is maintained in a fully dissolved state and subjected to an acid separation step to provide a sodium sulfate enriched phase, which may be used to maintain sulfur concentration in the Kraft pulping process, and a sulfuric acid phase. Chlorine ions can be separated with the sulfuric acid phase. The sulfuric acid phase can be recycled to the chlorine dioxide generator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.