Patent · US Active

Method for lignin separation from black liquor involving multiple acidification steps

US9175438B2 · kind B2 · utility

1Cited by

2References

10Claims

0Family size

Assignee

VALMET AB · SE

Inventors

Martin Wimby · Torslanda, SE
Mattias Svensson · Säve, SE
Henrik Wallmo · Hagfors, SE
Fredrik Ohman · Gävle, SE
Per Tomani · Huddinge, SE
Lars-Erik ÅKERLUND · Sollentuna, SE

Key dates

Filing date	Nov 11, 2011
Grant date	Nov 3, 2015
Priority date	—
Expiry date	Nov 19, 2031

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY02P40/40
WIPO fieldMacromolecular chemistry, polymers
WIPO sectorChemistry

Abstract

The method is for separation of lignin from original black liquor (BLIN) and has the following phases in sequence. A first precipitation phase (PR1) for precipitation of lignin by a first acidification of the original black liquor by adding a first acid or mixture of acids (G1a) followed by a first storage phase wherein precipitated lignin particles are allowed to increase in size, followed by a second precipitation phase (PR2) for precipitation of lignin by a further acidification of the original black liquor by adding a second acid or mixture of acids (G1b). By retaining the acidified black liquor for at least 25 minutes in the storage phase are the precipitated lignin particles allowed to grow in size and the filterability is improved considerably.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.