Kraft lignin recovery by ultrafiltration: economic feasibility and impact on the kraft recovery system

The widespread use of the kraft pulping process could provide a ready supply of lignin materials for many uses. Simulation studies demonstrate that recovery of the high-molecular-weight kraft lignin by ultrafiltration of a fraction of the black liquor flow is attractive from both an economic and an operational standpoint. Benefits are derived from relief of a furnace-limited recovery system and from the marketing of the lignin or modified lignin products. 10 references.