Producing Polysulfide by Electrolysis of White Liquor, Development and Integration with Kraft Pulping Process

Abstract The objective of this work was to determine the effect of sodium methyl mercaptide (SMM) on the minimization of peeling reactions of southern pine chips in the kraft pulping process. Two methods were evaluated for SMM addition to the pulping process: 1) pre-treatment before pulping or 2) co-addition with white liquor. The effect of SMM charge, pre-treatment temperature and time, and pH of pre-treatment liquor was studied. The experimental results showed about 1.5 to 2.5 % (on O.D. (oven dry) wood basis) increase in the pulp yield after pre-treatment with or co-addition of 4.38% SMM (on O.D. wood basis). The use of 4.38% SMM allowed a decrease of the white liquor effective alkali charge (EA, on O.D. wood basis) by 3%. 4.38% SMM charge seemed to be optimum for the pre-treatment. Pre-treatment at lower pH resulted in a significant decrease in yield and an increase in rejects. The increase in pulp yield was mostly due to the increased retention of cellulose and xylan. The retention of galactoglucomannan was negligible. About 80% of the cellulose yield increase is due to the suppression of primary peeling. The remainder (0.3–0.4% of the yield increase (on O.D. wood basis) is due to reduced alkaline hydrolysis and subsequent secondary peeling.

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Hemicellulose extraction from aspen chips prior to kraft pulping utilizing kraft white liquor

Biomass and Bioenergy ◽

10.1016/j.biombioe.2011.12.008 ◽

2012 ◽

Vol 37 ◽

pp. 229-236 ◽

Cited By ~ 16

Author(s):

Ai Jun ◽

Ulrike W. Tschirner ◽

Zachary Tauer

Keyword(s):

Kraft Pulping ◽

White Liquor

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Producing Polysulfide by Electrolysis of White Liquor, Integrated with Kraft Pulping Process

JAPAN TAPPI JOURNAL ◽

10.2524/jtappij.65.906 ◽

2011 ◽

Vol 65 (9) ◽

pp. 906-911

Author(s):

Kazuhiro Kurosu

Keyword(s):

Kraft Pulping ◽

White Liquor

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Impact of sulfidity on the kraft pulping of eucalyptus

BioResources ◽

10.15376/biores.15.2.3945-3961 ◽

2020 ◽

Vol 15 (2) ◽

pp. 3945-3961 ◽

Cited By ~ 1

Author(s):

Regina Maria Gomes ◽

Francides Gomes da Silva Júnior

Keyword(s):

Kraft Pulp ◽

Kraft Pulping ◽

Kappa Number ◽

White Liquor ◽

Eucalyptus Kraft Pulp ◽

Alkali Consumption ◽

Wood Consumption ◽

Optimized Conditions

This study aimed to evaluate the influence of white liquor sulfidity on the efficiency of the kraft pulping process. For this study, Eucalyptus spp. chips were used. Laboratory cooking with variable sulfidity levels (0 to 40% at 5% intervals) was conducted under previously optimized conditions, aiming to obtain pulp with a Kappa number of 18 ± 0.9 and residual effective alkali between 9 and 12 gL-1. At the end of each cook, Kappa number, solids generation, specific wood, and alkali consumption were evaluated. The sulfidity variation in white liquor influenced all analyzed parameters, and concerning the specific wood consumption, a distinct behavior was observed for the low sulfidity (S ≤ 19.52%) and high sulfidity regions (S ˃ 19.52%). Based on the obtained results, the production of eucalyptus kraft pulp with white liquor sulfidity of approximately 20% is recommended.

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Potential contribution of anion exclusion to hydroxide penetration in green liquor-modified kraft pulping

Holzforschung ◽

10.1515/hf-2013-0208 ◽

2014 ◽

Vol 68 (6) ◽

pp. 617-621 ◽

Cited By ~ 1

Author(s):

Ved Naithani ◽

Hasan Jameel ◽

Sujit Banerjee ◽

Peter W. Hart ◽

Lucian A. Lucia

Keyword(s):

Chip Thickness ◽

Kraft Pulping ◽

Full Scale ◽

Partial Substitution ◽

Potential Contribution ◽

Green Liquor ◽

White Liquor ◽

Anion Exclusion

Abstract Partial substitution of green liquor for white liquor in kraft pulping reduces calcining energy and reportedly enhances product properties. However, a full-scale trial showed that pulper rejects increased when green liquor substitution levels approached 10%. Imaging experiments and laboratory pulping runs demonstrate that the slower diffusion of hydroxide in the presence of green liquor carbonate is likely responsible for the elevated rejects. Green liquor substitution becomes increasingly more viable with decreasing chip thickness. Hence, such an approach should be especially suited to sawdust pulping where diffusion is not rate determining.

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Brownstock washing: A review of the literature

TAPPI Journal ◽

10.32964/tj13.1.9 ◽

2014 ◽

Vol 13 (1) ◽

pp. 9-19 ◽

Cited By ~ 1

Author(s):

RICARDO B. SANTOS ◽

PETER W. HART

Keyword(s):

High Efficiency ◽

Black Liquor ◽

Material Balance ◽

Kraft Pulping ◽

Wash Water ◽

Pulp Fibers ◽

Kraft Process ◽

Cooking Process ◽

Materials Used ◽

Entrapped Air

Brownstock washing is a complex, dynamic process in which dirty wash water or weak black liquor (dissolved organic and inorganic material obtained from the pulp cooking process) is separated from pulp fibers. The use of material balance techniques is of great importance to identify potential problems and determine how well the system is operating. The kraft pulping industry was the first known to combine pulp washing with the recovery of materials used and produced in the wood cooking process. The motivation behind materials recovery is economic, and more recently, environmentally driven. The chemicals used in the kraft process are expensive as compared to those used in the sulfite process. For the kraft process to be economically viable, it is imperative that a very high percentage of the cooking chemicals be recovered. To reach such high efficiency, a variety of washing systems and monitoring parameters have been developed. Antifoam additives and processing aids have also played an important role in increasing washing effectiveness. Antifoam materials help attain washing effectiveness by preventing entrapped air from forming in the system, which allows for an easier, unimpeded flow of filtrate through the screens and washers.

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Co-cooking nonwoods with hardwoods

TAPPI Journal ◽

10.32964/tj13.6.19 ◽

2014 ◽

Vol 13 (6) ◽

pp. 19-24

Author(s):

TROY RUNGE ◽

CHUNHUI ZHANG

Keyword(s):

High Performance Liquid Chromatography ◽

High Performance ◽

Paper Industry ◽

Pulp And Paper Industry ◽

Strength Properties ◽

Agricultural Residues ◽

Kraft Pulping ◽

Pulp And Paper ◽

Strength Increase ◽

Xylan Content

Agricultural residues and energy crops are promising resources that can be utilized in the pulp and paper industry. This study examines the potential of co-cooking nonwood materials with hardwoods as means to incorporate nonwood material into a paper furnish. Specifically, miscanthus, switchgrass, and corn stover were substituted for poplar hardwood chips in the amounts of 10 wt %, 20 wt %, and 30 wt %, and the blends were subjected to kraft pulping experiments. The pulps were then bleached with an OD(EP)D sequence and then refined and formed into handsheets to characterize their physical properties. Surprisingly, all three co-cooked pulps showed improved strength properties (up to 35%). Sugar measurement of the pulps by high-performance liquid chromatography suggested that the strength increase correlated with enriched xylan content.

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Characterization of dissolved material during the initial phase of softwood kraft pulping

TAPPI Journal ◽

10.32964/tj12.1.37 ◽

2013 ◽

Vol 12 (1) ◽

pp. 37-43 ◽

Cited By ~ 1

Author(s):

HANNU PAKKANEN ◽

TEEMU PALOHEIMO ◽

RAIMO ALÉN

Keyword(s):

Mass Transfer ◽

Molecular Mass ◽

Initial Phase ◽

Degradation Products ◽

Kraft Pulping ◽

Reaction Products ◽

Cooking Temperature ◽

Molecular Masses ◽

Aliphatic Carboxylic Acids

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.

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Applicability of electrodialysis to the separation of sodium acetate from synthetic alkaline hardwood extract

TAPPI Journal ◽

10.32964/tj14.11.695 ◽

2015 ◽

Vol 14 (11) ◽

pp. 695-708 ◽

Cited By ~ 3

Author(s):

RAVIKANT PATIL ◽

CHI TRUONG ◽

JOSEPH GENCO ◽

HEMANT PENDSE ◽

ADRIAAN VAN HEININGEN

Keyword(s):

Current Density ◽

Sodium Sulfate ◽

Sodium Acetate ◽

Separation Efficiency ◽

Feed Concentration ◽

Initial Concentration ◽

White Liquor ◽

Complete Extraction ◽

Electro Osmosis ◽

Preliminary Separation

Our objective was to develop a process for recovering acetyl groups from industrial northeast hardwood chips. Extraction experiments showed that the white liquor charge of 6% effective alkali at 50°C and liquor-to-wood ratio of 4:1 leads to the complete extraction of acetyl groups from industrial hardwood chips. Electrodialysis was assessed as a technique for separating and concentrating sodium acetate from synthetic hardwood extract. Preliminary separation experiments using dilute sodium acetate showed that the sodium acetate can be concentrated up to approximately 24% by weight from an initial concentration of about 2% by weight. The effects of current density, feed concentration, electro-osmosis, and osmosis on the separation of sodium acetate were evaluated. Finally, selectivity experiments were performed to study the effect of various components of the white liquor on the separation of sodium acetate. Fully oxidized synthetic white liquor was used in selectivity experiments to avoid deleterious effects of Na2S. Selectivity experiments using synthetic oxidized white liquor showed a significant decrease in the separation efficiency due to the presence of sodium hydroxide, sodium carbonate, and sodium sulfate in the synthetic extract.

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Polysulfide-borohydride modification of southern pine alkaline pulping integrated with hydrothermal pre-extraction of hemicelluloses

TAPPI Journal ◽

10.32964/tj10.7.9 ◽

2011 ◽

Vol 10 (7) ◽

pp. 9-16

Author(s):

SUNG-HOON YOON ◽

HARRY CULLINAN ◽

GOPAL A. KRISHNAGOPALAN

Keyword(s):

Loblolly Pine ◽

Sodium Borohydride ◽

Kraft Pulping ◽

Hot Water ◽

Pulp Yield ◽

Paper Strength ◽

Southern Pine ◽

Two Stage ◽

Simultaneous Treatment ◽

Process Modification

We studied three process modifications to investigate their effects on the property and yield recovery capabilities of kraft pulping integrated with hemicellulose pre-extraction of southern pine. Loblolly pine chips were pre-extracted with hot water until the sugar extraction yield reached the targeted value of 10% and then subjected to conventional and modified kraft pulping. Modification included polysulfide pretreatment; polysulfide-sodium borohydride dual pretreatment, and polysulfide followed by polysulfide-sodium borohydride dual pretreatment two-stage pretreatments prior to kraft pulping. In the first modification, about 5% of the lost pulp yield (total 7%) caused by hemicellulose pre-extraction could be recovered with 15%-20% polysulfide pretreatment. Complete recovery (7%) was achieved with simultaneous pretreatment using 15% polysulfide and 0.5% sodium borohydride with 0.1% anthraquinone in polysulfide-sodium borohydride dual pretreatment. Two-stage pretreatment using recycled 15% polysulfide followed by simultaneous treatment of 6% polysulfide and 0.4%–0.5% sodium borohydride with 0.1% anthraquinone also achieved 100% yield recovery. Continuous recycling of 15% polysulfide employed in the two-stage process modification maintained its yield protection efficiency in a repeated recycling cycle. No significant changes in paper strength were found in handsheets prepared from the three process modifications, except for a minor reduction in tear strength.

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