US 11,866,456 B2
Process for treating lignin
Michael A. Lake, Mt. Pleasant, SC (US); John C. Blackburn, Easley, SC (US); and J. George Hayden, Awendaw, SC (US)
Assigned to Liquid Lignin Company, Georgetown, SC (US)
Filed by Liquid Lignin Company
Filed on Jul. 12, 2021, as Appl. No. 17/372,872.
Claims priority of provisional application 63/051,609, filed on Jul. 14, 2020.
Prior Publication US 2022/0017555 A1, Jan. 20, 2022
Int. Cl. C07G 1/00 (2011.01); D21C 11/00 (2006.01)
CPC C07G 1/00 (2013.01) [D21C 11/0007 (2013.01)] 20 Claims
OG exemplary drawing
 
19. A method for producing a lignin product from black liquor, said method comprising:
in a first carbonation step, carbonating said black liquor with CO2 to reduce a pH of said black liquor and form a partially carbonated black liquor;
transferring an entire volume of said partially carbonated black liquor to a second carbonation step;
in said second carbonation step, carbonating said partially carbonated black liquor with CO2 to reduce a pH of said partially carbonated black liquor and form a carbonated black liquor;
phase separating said carbonated black liquor into a dense liquid-lignin phase and a light lignin-depleted liquid phase;
acidifying said dense liquid-lignin phase to neutralize basic components from said dense liquid-lignin phase and evolve gaseous CO2;
generating a porous, solid lignin in response to evolving said gaseous CO2 during acidifying; and
washing said porous, solid lignin to remove ash.