Patent ID: 9139606
Filing Date: 2015-09-22
Classification: B01J,C07G,D21C

Abstract:
1. A method for continuous precipitation of lignin from black liquor, the method comprising: flowing black liquor under pressure in a flow-through reactor with a dwell time of less than 300 s, applying an acidifying agent to the black liquor in the flow-through reactor at one or more feeding sites to lower pH of the black liquor to a precipitation point of lignin and forming an acidifying agent treated black liquor under pressure, wherein the acidifying agent is selected from carbon dioxide, acid, or combinations thereof, releasing the acidifying agent treated black liquor from the flow-through reactor thereby releasing the pressure of the acidifying agent treated black liquor and precipitating at least some of the lignin in the acidifying agent treated black liquor, and separating precipitated lignin particles from the acidifying agent treated black liquor.