Method for precipitating lignin from black liquor by utilizing waste gases
US9067959B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 2009 |
| Grant date | Jun 30, 2015 |
| Priority date | — |
| Expiry date | Nov 29, 2030 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/04
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The method is for separation of lignin from original black liquor. Lignin is precipitated in a first acidification stage followed by dewatering a first lignin suspension while forming a first filter cake. The first lignin filter cake is suspended in a second acidification stage whereupon a second lignin suspension is obtained. The second lignin suspension is dewatered to form a second filter cake. The second filter cake is washed and the washed second lignin cake is dewatered to obtain a lignin product. Waste gases from the second acidification stage is recirculated back to the first acidification stage and mixed with the original black liquor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.