Concentration and purification of lignin in hardwood kraft pulping liquor by ultrafiltration and nanofiltration

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Concentration and purification of lignin in hardwood kraft pulping liquor by ultrafiltration and nanofiltration. / Jönsson, Ann-Sofi; Nordin, Anna-Karin; Wallberg, Ola.

I: Chemical Engineering Research & Design, Vol. 86, Nr. 11A, 2008, s. 1271-1280.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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T1 - Concentration and purification of lignin in hardwood kraft pulping liquor by ultrafiltration and nanofiltration

AU - Jönsson, Ann-Sofi

AU - Nordin, Anna-Karin

AU - Wallberg, Ola

PY - 2008

Y1 - 2008

N2 - Today, there is considerable interest in integrated forest biorefineries which, besides pulp, produce high-value-added products, such as, polymers and carbon fibres. Lignin is the major non-cellulosic constituent of wood. It is a complex, amorphous highly crosslinked polyphenolic. Lignosulphonate in spent liquor in sulphite mills has long been isolated using ultra filtration. Generally, precipitation is used to extract the lignin from kraft black liquor. The liquor is commonly withdrawn from the evaporation unit in the recovery system, where the dry substance is optimal for precipitation. Lately, interest in the isolation of lignin by ultrafiltration of kraft black liquor has arisen. The concentration of the liquor is not that critical, and there is therefore considerable freedom in the choice of liquor for treatment with ultra filtration. In this work, the influence of membrane cut-off, transmembrane pressure and cross-flow velocity during ultrafiltration of cooking liquor and black liquor was studied. The extraction of lignin from hardwood black liquor withdrawn before the evaporation unit was investigated. A hybrid ultrafiltration/nanofiltration process was used. The lignin concentration was 60 g/l in the black liquor and 165 g/l in the product stream (the narrofiltration retentate). A cost estimate indicates a production cost of (sic)33 per tonne of lignin. (C) 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

AB - Today, there is considerable interest in integrated forest biorefineries which, besides pulp, produce high-value-added products, such as, polymers and carbon fibres. Lignin is the major non-cellulosic constituent of wood. It is a complex, amorphous highly crosslinked polyphenolic. Lignosulphonate in spent liquor in sulphite mills has long been isolated using ultra filtration. Generally, precipitation is used to extract the lignin from kraft black liquor. The liquor is commonly withdrawn from the evaporation unit in the recovery system, where the dry substance is optimal for precipitation. Lately, interest in the isolation of lignin by ultrafiltration of kraft black liquor has arisen. The concentration of the liquor is not that critical, and there is therefore considerable freedom in the choice of liquor for treatment with ultra filtration. In this work, the influence of membrane cut-off, transmembrane pressure and cross-flow velocity during ultrafiltration of cooking liquor and black liquor was studied. The extraction of lignin from hardwood black liquor withdrawn before the evaporation unit was investigated. A hybrid ultrafiltration/nanofiltration process was used. The lignin concentration was 60 g/l in the black liquor and 165 g/l in the product stream (the narrofiltration retentate). A cost estimate indicates a production cost of (sic)33 per tonne of lignin. (C) 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

KW - Nanofiltration

KW - Ultrafiltration

KW - Kraft black liquor

KW - Cost estimate

KW - Lignin

U2 - 10.1016/j.cherd.2008.06.003

DO - 10.1016/j.cherd.2008.06.003

M3 - Article

VL - 86

SP - 1271

EP - 1280

JO - Chemical Engineering Research & Design

JF - Chemical Engineering Research & Design

SN - 0263-8762

IS - 11A

ER -