Method for recovering low molecular weight lignin from a filtrate
US9982004B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 2013 |
| Grant date | May 29, 2018 |
| Priority date | — |
| Expiry date | Aug 22, 2033 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/0007
- WIPO fieldBiotechnology
- WIPO sectorChemistry
Abstract
The invention relates to a method for recovering low molecular weight lignin from a filtrate, wherein the low molecular weight lignin includes lignin molecules having a molecular weight of 3000 g/mol or lower, wherein the filtrate is obtained from a process where lignin is precipitated from black liquor and the formed precipitate is separated therefrom by filtration resulting in the filtrate including low molecular weight lignin being formed, and wherein the method includes the following steps: a) adjusting the pH of the filtrate to a value of 3-4 for precipitating lignin in the filtrate; b) separating the precipitated lignin from the filtrate; c) reslurrying the separated lignin until the dry solids content of the slurry is 25-40 weight-% and adjusting the pH of the slurry to a value of 2-3; d) washing the slurry; and e) separating the lignin from the slurry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.