Sorption of corn cob and oat spelt arabinoxylan onto softwood kraft pulp

Holzforschung ◽  
2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Felipe Ramírez ◽  
Jürgen Puls ◽  
Virgilio Zúñiga ◽  
Bodo Saake
Keyword(s):  
Kraft Pulp ◽  
Strength Properties ◽  
Degree Of Polymerization ◽  
Alkaline Extraction ◽  
Corn Cob ◽  
Tear Strength ◽  
Steam Extraction ◽  
Softwood Kraft Pulp ◽  
High Degree ◽  
Oat Spelt

Abstract Arabinoxylans from corn cob and oat spelt were studied in sorption experiments onto bleached and unbleached softwood kraft pulp. The corn cob (CC) xylans were produced by steam extraction (SE-CC) and alkaline extraction (NaOH-CC), while the oat spelt xylan (NaOH-OS) was obtained by alkaline extraction. Both alkaline extracted xylans exhibited a high degree of polymerization (DP) (230–240), whereas the steam extraction induced a significant degradation resulting in DPs around 36. Investigation of the xylan addition mode revealed that adding xylan before beating of pulp is most effective for increasing the beating degree and the strength properties. The tensile and burst indices are improved by xylan addition over the whole range of beating degrees. In contrast to that, the tear strength is increased significantly for unbeaten pulps but declines after beating, compared to the reference. Xylan sorption rates are increased with prolonged beating. Highest sorption rates are observed for the NaOH-OS (12–32%) and lowest for the SE-CC xylan (6.6–14%). In general, the alkaline extracted xylans have a better performance, most likely as a result of their higher molar masses.

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp • part 2: economic analysis of chemical and steam consumption

TAPPI Journal ◽  
2010 ◽  
Vol 9 (9) ◽  
pp. 47-53 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Chlorine Dioxide ◽  
Previous Investigation ◽  
Kraft Pulp ◽  
Energy Costs ◽  
Alkaline Extraction ◽  
Stage Versus ◽  
Kraft Pulps ◽  
Steam Consumption ◽  
Elemental Chlorine ◽  
Softwood Kraft Pulp

Our previous investigation [1] re-analyzed the data from Basta and co-workers (1992 TAPPI Pulping Conference) to demonstrate how oxidative alkaline extraction can be augmented and how these changes affect chlorine dioxide consumption with elemental chlorine-free (ECF) sequences. The current study manipulates extraction delignification variables to curtail bleaching costs with a conventional U.S. Southern softwood kraft pulp. The economic advantages of ~0.35% to 0.65% H2O2 peroxide reinforcement in a 70°C (EOP)-stage versus 90°C (EO)-stage are predisposed to the brightness targets, to short or long bleach sequences, and to mill energy costs. Minimized bleaching costs are generally realized when a 90°C (EO) is employed in D0(EO)D1 bleaching, whereas a 70°C (EOP) is economically advantageous for D0(EOP)D1E2D2 bleaching. The findings we disclose here help to clarify previous ECF optimization studies of conventional softwood kraft pulps.

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp – part 1: impact of oxidative extraction on chlorine dioxide stoichiometry

TAPPI Journal ◽  
2010 ◽  
Vol 9 (8) ◽  
pp. 27-35 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Decision Making ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Alkaline Extraction ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Kraft Pulp Bleaching ◽  
Softwood Kraft Pulp ◽  
Chemical Usage ◽  
Minimize Costs

The present investigation meticulously analyzes how oxidative alkaline extraction can be augmented through process changes, and how these augmentations can be leveraged to optimize chlorine dioxide usage with elemental chlorine-free (ECF) sequences for a conventional softwood kraft pulp. Bleaching data from Basta and co-workers (1992 TAPPI Pulping Conference) are re-examined and re-interpreted in this study. We determined that ~60% to 65% of the overall ClO2 charge should be applied in the D0-stage. Peroxide addition to an (EOP) can replace 0.6 to 2.5 Kg. ClO2 per Kg H2O2. Boosting the (EO) temperature to 80°C is equivalent to a 70°C (EOP) with 0.25% to 0.30% H2O2,whereas a 90°C (EO) is equivalent to 0.50% – 0.75% H2O2 in a 70°C (EOP). The stoichiometric bleaching data from this study can guide decision-making for lowering chemical usage and minimize costs to reach target brightness levels with three- and five-stage sequences.

Modeling of alkaline extraction chemistry and kinetics of softwood kraft pulp

Holzforschung ◽  
2014 ◽  
Vol 68 (7) ◽  
pp. 733-746 ◽  
Author(s):  
Susanna Kuitunen ◽  
Ville Tarvo ◽  
Tiina Liitiä ◽  
Stella Rovio ◽  
Tapani Vuorinen ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Oxygen Demand ◽  
Alkaline Extraction ◽  
Fiber Wall ◽  
Transfer Equations ◽  
Softwood Kraft Pulp ◽  
Engineering Parameters ◽  
Liquid Mass Transfer ◽  
Kinetics Of

Abstract A comprehensive model for alkaline extraction (E) of chlorine dioxide delignified (D0) softwood kraft pulp (KP) is presented. The dynamics of the process is modeled by taking into account both irreversible and reversible chemical reactions and gas-liquid and liquid-liquid mass transfer. Equations linking molecular-scale composition (amounts of monomeric lignin and carbohydrate structures) and general engineering parameters [κ number (KN), brightness, intrinsic viscosity, total organic carbon (TOC), chemical oxygen demand (COD), etc.] are presented. The model is capable of reproducing the development of KN and brightness from the molecular-level kinetics. Reactions responsible for the darkening of chlorine dioxide bleached (D0) pulp in alkali, brightening of pulp due to the action of hydrogen peroxide and oxygen, and reduction in KN were identified. The model predicts the chemical composition of both fiber wall and filtrate. This feature enables studies concerning the interaction of the AE chemistry with upstream (D0 washing) and downstream (D1 stage) processes. Quantitative physicochemical modeling approach also points out shortcoming in the present knowledge.

Relationships Between Mixing Method, Microstructure and Strength of Nr:Br Blends

2001 ◽  
Vol 74 (1) ◽  
pp. 1-15 ◽  
Author(s):  
J. Clarke ◽  
B. Clarke ◽  
P. K. Freakley
Keyword(s):  
Process Development ◽  
Strength Properties ◽  
Single Stage ◽  
Tear Strength ◽  
Mixing Method ◽  
Stage Process ◽  
Filler Dispersion ◽  
Mixing Techniques ◽  
High Degree ◽  
Filler Distribution

Abstract Much published literature on the way in which phase morphology and filler distribution affect blend properties is contradictory or confusing. Experiments were carried out to elucidate the relationships and to determine whether the use of compatibilizers or special mixing techniques might have a beneficial effect on natural rubber:butadiene rubber (NR:BR) blend properties. NR:BR blends were prepared using both a masterbatch method and a single-stage mixing method. A cure system which gave an even distribution of crosslinks between the phases was used. The morphology, tensile strength and tear strength properties of the blends were measured. Results indicated a high degree of compatibility with fine textured blends (domain sizes < 1µm) being quickly and easily produced, even from masterbatches of very different viscosities. Strength properties of these fine textured masterbatch blends could be predicted by applying the simple rule of mixtures to properties of individual compounds mixed under the same conditions. Although in particular situations a coarse morphology could result in high tear resistance values, for most applications a fine textured morphology gives the most satisfactory overall tensile and tear strength properties. For blends mixed in a single-stage process, development of a fine textured morphology was much quicker than that of filler dispersion. For NR:BR blends containing an optimum cure system it was concluded that the mixing cycle should be chosen to optimize filler dispersion and that use of a compatibilizer will not significantly shorten the mixing cycle or improve the properties of the blend.

scholarly journals Use of fines-enriched chemical pulp to increase CTMP strength

TAPPI Journal ◽  
2021 ◽  
Vol 20 (4) ◽  
pp. 255-263
Author(s):  
ELISABETH BJORK ◽  
MIKAEL BOUVENG ◽  
HANNES VOMHOFF ◽  
PER ENGSTRAND
Keyword(s):  
Kraft Pulp ◽  
Fine Fraction ◽  
Strength Properties ◽  
Strength Increase ◽  
Fines Content ◽  
Chemical Pulp ◽  
Softwood Kraft Pulp

In this study, fines-enriched pulp (FE-pulp)—the fine fraction of highly-refined kraft pulp—was benchmarked against highly-refined kraft pulp (HRK-pulp) as a strength agent in eucalyptus chemithermomechanical pulp (CTMP). Both the FE-pulp and the HRK-pulp were produced from unbleached softwood kraft pulp, and equal amounts of those strength agents were added to the original CTMP, as well as to washed CTMP, where most of the fines had been removed. The effects of the added strength agents were evaluated with laboratory handsheets. The FE-pulp proved to be twice as effective as HRK-pulp. Both HRK-pulp and FE-pulp increased the strength of the CTMP handsheets. The bulk of the handsheets decreased, however, as well as the drainability. The addition of 5% FE-pulp resulted in the same strength increase as an addition of 10% HRK-pulp, as well as the same decrease in bulk and CSF. For the handsheets of washed CTMP, the strengths were not measurable; the CTMP lost the sheet strength when the CTMP-fines content was reduced through washing. The reduced strength properties were compensated for by the addition of chemical pulp fines that proved to be an efficient strength agent. The addition of 5% FE-pulp restored the strength values, and at a higher bulk and higher drainability.

scholarly journals Softwood kraft pulp fines: application and impact on specific refining energy and strength properties

Cellulose ◽  
2020 ◽  
Vol 27 (17) ◽  
pp. 10359-10367
Author(s):  
Daniel Mandlez ◽  
Lukas Zangl-Jagiello ◽  
Rene Eckhart ◽  
Wolfgang Bauer
Keyword(s):  
Tensile Strength ◽  
Linear Relationship ◽  
Apparent Density ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Air Permeability ◽  
Research Interest ◽  
Paper Properties ◽  
Softwood Kraft Pulp ◽  
Breaking Length

AbstractAlong with the emergence of micro and nanofibrillated celluloses and their application in papermaking, the influence of the so called fines fraction of pulps on both process and product properties has received increasing research interest in recent years. Several researchers have experimented with primary and/or secondary pulp fines to assess their effects on paper properties with not always consistent results. Our work focuses on the targeted application of the primary fines fraction of an unbleached softwood kraft pulp. The primary fines are separated from the pulp to be subsequently added to achieve blends of $$5\%, 9\%$$ 5 % , 9 % and $$12\%$$ 12 % primary fines content. These blends were then refined in a PFI mill to evaluate the effect of the primary fines on refining as well as on paper properties of hand sheets prepared from these pulps. It is shown that the addition of primary fines enhances tensile strength in the unrefined and slightly refined state, while the maximum tensile strength of the highly refined reference pulp is not increased. A slightly increased dewatering resistance (Schopper Riegler) at comparable air permeability (Gurley) for a given tensile strength was also observed. The linear relationship between tensile index and apparent sheet density seems to be affected in the unrefined and slightly refined state where the breaking length of the fines enriched samples is higher for a given apparent density.

Alkaline extraction of softwood kraft pulp with sodium carbonate

1991 ◽  
Vol 6 (2) ◽  
pp. 89-94 ◽  
Author(s):  
Ulf Germghrd ◽  
Annika Brodén ◽  
Paivi Isoaho
Keyword(s):  
Sodium Carbonate ◽  
Kraft Pulp ◽  
Alkaline Extraction ◽  
Softwood Kraft Pulp

Fibre characteristics and paper properties of formic acid / peroxyformic acid birch pulps

1997 ◽  
Vol 12 (4) ◽  
pp. 237-243 ◽  
Author(s):  
Anu Seisto ◽  
Krisriina Poppius-Levlin
Keyword(s):  
Tensile Strength ◽  
Formic Acid ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Strength Development ◽  
Paper Properties ◽  
Fibre Breakage ◽  
High Degree ◽  
Peroxyformic Acid

Abstract The fibre and paper properties of nine unbleached formic acid / peroxyformic acid (MILOX) pulps with kappa number 6-20 were studied and compared with a kraft pulp with kappa number 20. The degree of deformation was greater in the MILOX fibres, affecting the paper properties of the MILOX pulps. The large number of curl and kinks in the MILOX fibres were probably caused mechanically. The MILOX fibres showed greater conformability, resulting in higher paper density. The defects in the MILOX fibres were apparently so severe as to cause fibre breakage during PFI beating of the pulps. As a result of both fibre deformation and breakage, the tensile strengths of the MILOX pulps were lower than that of the reference kraft pulp, and tensile strength development during beating was slower. The tear strength of the best MILOX pulp was lower than that of the kraft pulp when compared at the same tensile index. Fibre deformation in both MILOX and the kraft pulp increased during bleaching. The kinks in the fibres were possibly set into position, giving the bleached MILOX pulps poorer bonding ability and lower paper density. A high degree of fibre defo~mation had the same effect on the tensile strength development of the bleached MILOX pulps as it did in the unbleached state. The light scattering properties of the MlLOX pulps were better than those of the kraft pulp, possibly due to the higher fines content of the MILOX pulps. The results indicate that more attention should be given to mechanical treatments during MILOX pulping in order to bring the strength properties closer to those of kraft pulp.

An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 157-164 ◽  
Author(s):  
Shengdan Wang ◽  
Wenhua Gao ◽  
Kefu Chen ◽  
Jinsong Zeng ◽  
Jun Xu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Congo Red ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Standard Curve ◽  
Congo Red Dye ◽  
Mechanical Disintegration ◽  
Softwood Kraft Pulp ◽  
White Water ◽  
Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

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