Work

Pilot-scale nanofiltration and techno-economic evaluation of lignin recovery from kraft black liquor

Year: 2024

Type: article

Abstract: This pilot-scale study investigates the possibility of using nanofiltration after ultrafiltration to improve lignin recovery from kraft black liquor in a pulp mill. The nanofiltration step can increase overall lignin recovery and provide a clean permeate that could be used in the smelt dissolving tank to produce green liquor. Nanofiltration of kraft black liquor ultrafiltration permeate was performed under two operating conditions: (A) 50 °C at 25 bar, and (B) 70 °C at 15 bar, which led to a lignin retention of 82% and 75%, respectively. Experimental data from condition A were used in a techno-economic analysis where four scenarios were evaluated: (1) a reference scenario, without lignin separation; (2) a scenario in which the ultrafiltration permeate was returned to the evaporators; (3) a scenario including ultrafiltration and nanofiltration, where the nanofiltration permeate was sent to the smelt dissolving tank; and (4) a scenario including ultrafiltration and nanofiltration, where the nanofiltration retentate was sent to the evaporators and the nanofiltration permeate to the smelt dissolving tank. The reduced energy consumption of the evaporators in scenario 4 resulted in an increase in sold electrical power of 19.4 GWh/y, giving a pay-back time on the investment in the nanofiltration plant of 2.2 years.

Source: Journal of Wood Chemistry and Technology

DOI: 10.1080/02773813.2024.2416651

Authors: Mariona Battestini-Vives, Johan Thuvander, Anders Arkell, Frank Lipnizki

Institution: Lund University

Language: English

Topic: Lignin and Wood Chemistry

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Affordable and clean energy, Clean water and sanitation

Open Access status: hybrid

Funder: Energimyndigheten