Process for treating lignin
US11866456B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2021 |
| Grant date | Jan 9, 2024 |
| Priority date | — |
| Expiry date | Jan 5, 2042 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/04
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
This invention provides improvements to processes for making granular lignin from black liquor. One of the improvements is that the use of a pre-carbonation column reduces the CO2 flow into the sparger of a carbonation column. The pre-carbonation column is used to reduce the pH of the black liquor to about 12. Another improvement is that it has been found that coalescing droplets into a bulk liquid-lignin phase can be enhanced by placing the exit of the carbonation column at or slightly beneath carbonated black liquor/liquid-lignin interface. It has also been found that operating the carbonation settler at a low pressure and pumping the liquid-lignin from the carbonation settler to the acidification reactor operating at a higher pressure allows recycling the vent gas from the acidification reactor to the pre-carbonation column. The invention also provides for a vent gas absorber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.