scholarly journals Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill

2012 ◽  
Vol 36 (6) ◽  
pp. 1163-1172 ◽  
Author(s):  
María Graciela Aguayo ◽  
Regis Teixeira Mendonça ◽  
Paulina Martínez ◽  
Jaime Rodríguez ◽  
Miguel Pereira
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Chemical Characteristics ◽  
Kraft Pulps ◽  
Opposite Wood ◽  
Alkali Consumption ◽  
Pulp Strength

Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.

Evaluation of beetle-killed white spruce for pulp and paper

1983 ◽  
Vol 13 (2) ◽  
pp. 246-250 ◽  
Author(s):  
Richard A. Werner ◽  
Erwin E. Elert ◽  
Edward H. Holsten
Keyword(s):  
White Spruce ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Kraft Pulps ◽  
High Quality ◽  
South Central ◽  
Dead Trees ◽  
Standing Trees ◽  
First Results

A kraft pulping study on standing white spruce (Piceaglauca (Moench) Voss) killed by spruce beetles (Dendroetonusrufipennis (Kirby)) in south central Alaska showed no difference in pulp yield between trees dead for 1 year and those dead for as long as 50 years. Strength properties of beetle-killed white spruce remained extremely high in all dead trees regardless of how long they had been dead, so they apparently could be used for producing high-quality kraft pulps. These are the first results reported in which standing trees dead for as long as 50 years produced high-quality bleached and unbleached pulps.

scholarly journals Properties of bleached pulp sheets of avocado wood (Persea americana Mill.) pulped by Kraft and Soda processes

2016 ◽  
Vol 12 (1) ◽  
pp. 29-36
Author(s):  
R. Vargas ◽  
J. R. Sanjuán D. ◽  
J. A. Silva G. ◽  
J. Rivera P. ◽  
F. J. Fuentes T. ◽  
...  
Keyword(s):  
Strength Properties ◽  
Kraft Pulping ◽  
Persea Americana ◽  
Raw Material ◽  
Kraft Pulps ◽  
Reaction Conditions ◽  
Elemental Chlorine ◽  
Chemical Pulping ◽  
Pulp Strength ◽  
Soda Pulp

Chips of avocado wood (Persea americana Mill.) were pulped by means of conventional Soda and Kraft pulping processes. The pulps were bleached with an elemental-chlorine-free sequence OD1-Eop-D2, pre-setting reaction conditions for the first chlorine dioxide stage (D1) . The results show that during the chemical pulping process, avocado wood is easier to cook than other hardwoods such as eucalyptus. The avocado pulp also showed a very good bleachability, reaching brightness levels of up to 92% ISO compared to 84% for eucalyptus after the ECF bleaching sequence. The avocado Kraft pulps required more chemical input in the bleaching sequence than the Soda pulps. On the other hand, the physico-mechanical properties of the pulp were not notably reduced by the bleaching process, the Kraft pulp being stronger than the soda pulp. Strength properties of avocado are similar to those of eucalyptus; therefore this raw material constitutes a worthwhile choice for cellulosic fiber supply.

Effect of bark content in mixed hardwood chips on pulp and papermaking properties

2020 ◽  
Vol 35 (3) ◽  
pp. 325-331
Author(s):  
Sandeep Kumar Tripathi ◽  
Izhar Alam ◽  
Nishi Kant Bhardwaj
Keyword(s):  
Strength Properties ◽  
Ash Content ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Raw Material ◽  
Pulp Yield ◽  
Physical Strength ◽  
Alkali Consumption ◽  
Unbleached Pulp

AbstractEffect of different proportions of bark in mixed hardwood (about 70 % eucalyptus and 30 % poplar) chips on pulp and papermaking properties was studied. Increased proportion of bark in raw material chips resulted in increased active alkali consumption, increased reject content in pulp and reduced pulp yield after kraft pulping. The unbleached pulp obtained with higher proportion of bark in mixed hardwood chips also has higher kappa number, lower brightness and viscosity as compared to pulp obtained with bark free mixed hardwood chips. The soda loss and ash content in pulp were severely increased from 12.8 kg/t to 312 kg/t of pulp and 0.7 % to 21.1 %, respectively with the increase of bark portion from 0 to 100 % in raw material furnish. The physical strength properties like tensile, burst and tear indices in the pulp obtained from bark were reduced by 58.5 %, 60.7 % and 68.4 %, respectively as compared to that with bark free mixed hardwood.

Application of Chelating Agents as Cooking Aids in Bamboo Pulping

2013 ◽  
Vol 750-752 ◽  
pp. 1520-1523
Author(s):  
Hong Xia Gao ◽  
Wen Hua He ◽  
Xiu Qiong Guan ◽  
Chun Liu ◽  
Bo Yuan
Keyword(s):  
Phosphonic Acid ◽  
Chelating Agents ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Pulp Yield ◽  
Diethylene Triamine ◽  
Bamboo Pulp ◽  
Kraft Cooking ◽  
Pulp Strength

The effect of chelating agents Diethylene Triamine Penta Methylene Phosphonic Acid in bamboo kraft cooking was studied. The results show that the bamboo pulp yield was 49.52% when DTPMPA dosage is 0.4%, at the same time the Kappa number was lower. With the increasing of DTPMPA dosage in bamboo kraft pulping, the bamboo pulp strength was increased.

Ethanol-Enhanced Alkaline Pulping of Arundo donax L. Reed: Influence of Solvent on Pulp Yield and Quality

Holzforschung ◽  
2002 ◽  
Vol 56 (5) ◽  
pp. 507-512 ◽  
Author(s):  
A. A. Shatalov ◽  
H. Pereira
Keyword(s):  
Ethanol Concentration ◽  
Arundo Donax ◽  
Pulp Yield ◽  
Kraft Pulps ◽  
Alkaline Pulping ◽  
Yield And Quality ◽  
Carbohydrate Complex ◽  
Ethanol Addition ◽  
Pulp Strength ◽  
Positive Effect

Summary The effect of solvent on yield and properties of ethanol-alkali pulps from Arundo donax L. was studied. Selectivity of pulping was significantly improved with increase in solvent proportion in the cooking liquor. A rise in ethanol concentration from 20 to 60% (by vol.) increased pulp yield from 44.0 to 48.9%, while decreasing residual lignin from 5.0 to 3.0%. Ethanol addition had a positive effect on preservation of carbohydrate complex against degradation in alkaline medium. Intrinsic viscosity of cellulose was improved up to 35% and xylan content increased from 8.6 to 12.1% with increase in ethanol concentration from 20 to 60%. The preservation of minor non-cellulosic polysaccharides with solvent addition was also observed. The papermaking properties of ethanol-alkali pulps were best for 20% ethanol content. An increase in solvent charge led to a drop in burst, tear and tensile pulp strength. Solvent addition assisted the conversion of glucuronic to hexenuronic acids, whereas the content of HexA in ethanol-alkali pulps of Arundo donax (about 10 μmol/g) was substantially lower than reported for kraft pulps from wood.

Influence of cellulose supramolecular structure on strength properties of chemical pulp

Holzforschung ◽  
2014 ◽  
Vol 68 (8) ◽  
pp. 861-866 ◽  
Author(s):  
Per Tomas Larsson ◽  
Lennart Salmén
Keyword(s):  
Supramolecular Structure ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Kraft Pulps ◽  
Chemical Pulp ◽  
Chemical Pulps ◽  
Fiber Wall ◽  
Tear Index ◽  
Pulp Strength ◽  
Selective Increase

Abstract The industrially produced chemical pulps have lower strength properties than those obtained under laboratory conditions, and this difference is referred to as the strength delivery (SD) problem. In this study, the hypothesis was put forward that the SD could, at least in part, be accounted for by the supramolecular structure of the cellulose microfibrils of the fiber wall. To test the hypothesis, two bleached softwood kraft pulps (BSKP) were manufactured from the same starting material with different degrees of cellulose aggregation, but the pulps were otherwise as similar as possible in other controllable respects. The chemical and physical properties, including the pulp strength, were tested. A selective increase of the degree of cellulose microfibril aggregation resulted in a pulp with a decreased tear index (TI) at a specified tensile index, and this decrease was similar in magnitude to what is typically encountered in SD. Accordingly, the current experimental study succeeded in mimicking the SD problem. The lateral fibril aggregate dimensions (LFAD) seem to play a pivotal role and it can be safely concluded in general that the supramolecular structure of cellulose in the fibers may be an important factor contributing to the SD problem.

Kinetics of ASAM and Kraft Pulping of Eucalypt Wood (Eucalyptus globulus)

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Isabel Miranda ◽  
Helena Pereira
Keyword(s):  
Eucalyptus Globulus ◽  
Initial Period ◽  
Reaction Times ◽  
Kraft Pulping ◽  
Kraft Pulps ◽  
Final Phase ◽  
Lower Mass ◽  
Lignin Removal ◽  
Mass Losses ◽  
Kinetics Of

Summary The kinetics of ASAM and kraft pulping of eucalypt wood (Eucalyptus globulus) were studied in relation to delignification and polysaccharide removal. In comparison to kraft, ASAM pulping had lower mass losses and delignification for the same temperature and reaction times (59.2% at Kappa 25 vs 50.0% at Kappa 17, at 180°C). The ASAM pulps have a higher brightness. ASAM pulping had a short initial period with no mass loss and lignin removal, followed by two reaction phases: a main phase where 61% of lignin was removed (at 180°C) and a subsequent final phase. In comparison to kraft, the main delignification rates of ASAM pulping were approximately 2.5 slower (at 180°C, −1.8 × 10−2 min−1 for ASAM and −4.2 × 10−2 for kraft pulping), and the calculated Arrhenius activation energies were higher (132.4 kJ mol−1 and 83.5 kJ mol−1, respectively). The loss of cellulose was relatively small (12.5 %) and lower than in kraft pulps.

Chemistry and kraft pulping of seven hybrid aspen clones. Dimension measurements on the vessels and UMSP of the cell walls

Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 505-510
Author(s):  
Inese Sable ◽  
Uldis Grinfelds ◽  
Martins Zeps ◽  
Ilze Irbe ◽  
Guna Noldt ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Cell Walls ◽  
Lignin Content ◽  
Strength Properties ◽  
Mean Value ◽  
Kraft Pulping ◽  
Populus Tremula ◽  
Stem Volume ◽  
Hybrid Aspen ◽  
Shape Factors

Abstract Micropropagated hybrid aspen clones (Populus tremuloides Michx.×Populus tremula L.) and a plus-tree (superior phenotypes selected) aspen (Populus tremula L.) were grown under similar conditions in the central part of Latvia. After cutting at the age of 12 years, 64 sample trees were examined. The dimensions of the vessels and the content of cellulose, lignin, extractives and ash were determined. The cell walls were characterised by UV microspectrophotometry (UMSP) in the UV range. The dimensions of fibres obtained by kraft pulping were determined such as length, width, and their shape factors. Coarseness measurements were performed, and strength properties of the handsheets were tested. One of the clones (no. 44) had a significantly higher stem volume of 208 dm3 and stem diameter of 17 cm at a height of 1.3 m. This clone had otherwise no notable differences to the other clones concerning the chemical composition, except a slightly higher lignin content (20.0% as compared with the mean value of 19.3% for other clones). Kraft cooking of hybrid aspen chips gave pulp yields in the range of 48.6–52.4%. Slightly higher strength properties (10–15%) were found for the handsheets prepared from a common aspen pulp (reference) as compared with those from hybrid aspen fibres.

Characterization of non-cellulosic glucans in Eucalyptus globulus Labill. wood and kraft pulp

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 478-482 ◽  
Author(s):  
Sara A. Lisboa ◽  
Dmitry V. Evtuguin ◽  
Carlos Pascoal Neto
Keyword(s):  
Eucalyptus Globulus ◽  
Fiber Surface ◽  
2D Nmr ◽  
Structural Features ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Naoh Solution ◽  
Nmr Techniques

Abstract The amount of non-cellulosic glucans in Eucalyptus globulus wood (approx. 4.5%) was assessed by extraction of sawdust with a 0.5 M NaOH solution at 90–120°C and the structural features were elucidated in a glucan-enriched polysaccharide fraction isolated by hot water extraction (120°C, 2 h). Isolated soluble glucans were characterized by wet chemistry methods and a set of 1D and 2D NMR techniques. The major proportion of glucans consisted of amylose (20%) and amylopectin (80%), although a small proportion of β-(1→3)-glucan (<0.2% on wood weight) was also detected. Although glucans are easily removed in the initial phase of kraft pulping, notable amounts were found in unbleached pulp and it was supposed that in the final stage of kraft pulping a fraction of α-glucan is precipitated onto the fiber surface and contributes to the pulp yield.

Sign in / Sign up

Export Citation Format

Share Document