- No CO2 addition needed!
- Less sulphuric acid needed in lignin separation
- Lower molecular weight and possibly more pure lignin
- Extra income from chemicals
- Lignin separation from Kraft or other alkaline black liquor
- Production of lower molecular weight lignin
- Black liquor is treated with oxygen or air under elevated pressure p=(5-20 bar) and relevated temperature T=(150-210 °C).
- Lignin and sugar degradation products react with dissolved oxygen in the aqueous phase forming acids, which consumes alkali so that pH drops even until 8.
- In certain condition lignin precipitates even without acid addition.
- CN103608514B (granted)
- FI123086 (granted)
- US9102533 (granted
- Priority 28.02.2011
Kristian Melin and Kari Parviainen
+358 50 3397534