Direct lignin depolymerization process from sulfur-free black liquors

Many of the pulp mill biorefinery concepts recently presented include removal of lignin from black liquor. In this work, the aim was to study how the change in liquor chemistry affected the evaporation of kraft black liquor when lignin was removed using the LignoBoost process. Lignin was removed from a softwood kraft black liquor and four different black liquors were studied: one reference black liquor (with no lignin extracted); two ligninlean black liquors with a lignin removal rate of 5.5% and 21%, respectively; and one liquor with maximum lignin removal of 60%. Evaporation tests were carried out at the research evaporator in Chalmers University of Technology. Studied parameters were liquor viscosity, boiling point rise, heat transfer coefficient, scaling propensity, changes in liquor chemical composition, and tube incrustation. It was found that the solubility limit for incrustation changed towards lower dry solids for the lignin-lean black liquors due to an increased salt content. The scaling obtained on the tubes was easily cleaned with thin liquor at 105°C. It was also shown that the liquor viscosity decreased exponentially with increased lignin outtake and hence, the heat transfer coefficient increased with increased lignin outtake. Long term tests, operated about 6 percentage dry solids units above the solubility limit for incrustation for all liquors, showed that the heat transfer coefficient increased from 650 W/m2K for the reference liquor to 1500 W/m2K for the liquor with highest lignin separation degree, 60%.

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Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽

10.32964/tj14.4.237 ◽

2015 ◽

Vol 14 (4) ◽

pp. 237-244 ◽

Cited By ~ 1

Author(s):

JONI LEHTO ◽

RAIMO ALÉN

Keyword(s):

Acetic Acid ◽

Betula Pendula ◽

Cooking Time ◽

Hot Water ◽

Partial Hydrolysis ◽

Chemical Pulping ◽

Black Liquors ◽

Aliphatic Carboxylic Acids ◽

Hydrolysis Of ◽

Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

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An eco-friendly biomass pretreatment strategy utilizing reusable enzyme mimicking nanoparticles for lignin depolymerization and biofuel production

Green Chemistry ◽

10.1039/d1gc01456k ◽

2021 ◽

Author(s):

Rajiv CHANDRA RAJAK ◽

Pathikrit Saha ◽

Mamata S Singhvi ◽

Darae Kwak ◽

Danil Kim ◽

...

Keyword(s):

Lignocellulosic Biomass ◽

Biofuel Production ◽

Biomass Pretreatment ◽

Enzyme Mimicking ◽

Lignin Depolymerization

Pretreatment of lignocellulosic biomass to specifically depolymerise lignin moieties without loss of carbohydrates as well as to minimize the generation of harmful intermediates during the process is a major challenge...

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Low-temperature alkali lignin depolymerization to functional chemicals

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-01478-x ◽

2021 ◽

Author(s):

Komal Saini ◽

Avnish Kumar ◽

Bijoy Biswas ◽

Thallada Bhaskar

Keyword(s):

Low Temperature ◽

Alkali Lignin ◽

Lignin Depolymerization

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Just beyond the reach of servitude: free black farmers in Antebellum South Carolina’s upcountry

American Nineteenth Century History ◽

10.1080/14664658.2021.1893482 ◽

2021 ◽

pp. 1-21

Author(s):

David W. Dangerfield

Keyword(s):

Antebellum South ◽

Free Black ◽

Black Farmers

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Behavior of xylans from the Eucalyptus species. Part 2. Characterization of 4-O-methylglucuronoxylans isolated from black liquors of kraft pulping of Eucalyptus grandis and E. urophylla

Holzforschung ◽

10.1515/hf-2012-0035 ◽

2013 ◽

Vol 67 (2) ◽

pp. 123-128

Author(s):

Andréia S. Magaton ◽

Teresa Cristina F. Silva ◽

Jorge Luiz Colodette ◽

Dorila Piló-Veloso ◽

Flaviana Reis Milagres ◽

...

Keyword(s):

Average Molecular Weight ◽

Eucalyptus Grandis ◽

Kraft Pulping ◽

Raw Material ◽

Size Exclusion ◽

Eucalyptus Species ◽

Exclusion Chromatography ◽

Ft Ir ◽

Black Liquors

Abstract 4-O-methylglucuronoxylans isolated from Eucalyptus grandis and Eucalyptus urophylla kraft black liquors (KBLs) were chemically characterized by Fourier transform infrared spectroscopy (FT-IR), size exclusion chromatography (SEC), and nuclear magnetic resonance (NMR) spectroscopy. Doses of alkali charge, expressed as active alkali (AA), were 16, 17, and 18% while the sulfidity was kept at 25%. Kappa numbers of 19.1, 17.5, and 16.1 for E. grandis and 20.4, 16.8, and 15.4 for E. urophylla were obtained. At higher alkali charges, the recovery of xylans from the KBLs was lower and the degree of substitution of xylans with uronic acids decreased. The average molecular weight (Mw) of the recovered xylans was greater under conditions of mild pulping, i.e., in the case of pulps with higher kappa numbers. Mw of xylans ranged from 16.1 to 19.1 kDa for E. grandis and from 15.4 to 20.4 kDa for E. urophylla. The xylans from KBL may be useful as pulp modifying agents or as a raw material for advanced applications.

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