scholarly journals Increasing Softwood Pulp Yield by Minimizing Primary Peeling of Wood Carbohydrates Using Sodium Methyl Mercaptide Before and During Kraft Pulping

2021 ◽  
Author(s):  
Ravikant A Patil ◽  
van Heiningen Adriaan
Keyword(s):  
Treatment Temperature ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Yield Increase ◽  
Sodium Methyl ◽  
White Liquor ◽  
Softwood Pulp ◽  
Dry Wood ◽  
Pre Treatment ◽  
Co Addition

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.

Stabilization, degradation, and dissolution behavior of Scots pine polysaccharides during polysulfide (K-PS) and polysulfide anthraquinone (K-PSAQ) pulping

Holzforschung ◽  
2015 ◽  
Vol 69 (9) ◽  
pp. 1049-1058 ◽  
Author(s):  
Markus Paananen ◽  
Stella Rovio ◽  
Tiina Liitiä ◽  
Herbert Sixta
Keyword(s):  
Scots Pine ◽  
Black Liquor ◽  
Kraft Pulping ◽  
Cooking Time ◽  
Dissolution Behavior ◽  
Pulp Yield ◽  
Yield Increase ◽  
Ion Concentrations ◽  
Kraft Process ◽  
Diffusion Phenomena

Abstract The behavior of Scots pine (Pinus sylvestris L.) polysaccharides was studied during modified kraft pulping processes of wood meal by polysulfide (K-PS) and polysulfide anthraquinone (K-PSAQ) at the hydroxide ion concentrations of 0.50 and 1.55 M [OH-] with a high liquor-to-wood (L/W) ratio of 200. The high L/W ratio was selected for avoiding diffusion phenomena and to be able to focus on the chemistry of polysaccharides. A comparison with the kraft process reference at 160°C revealed a substantial increase in pulp yield (6–7% in K-PS pulping and 7.5–10.5% in K-PSAQ pulping) mainly attributed to galactoglucomannan (GGM) stabilization. Due to the rapid delignification rate at 1.55 M [OH-] concentration, the temperature could be lowered from 160°C to 130°C without a notable prolongation of cooking time. In K-PS pulping at 130°C, no additional GGM stability was observed compared to 160°C, whereas cellulose and arabinoxylan preservation was improved. In K-PSAQ pulping, GGM preservation was also significantly improved. At 130°C, pulp yield increase of approximately 8% in PS pulping and more than 11% in PSAQ pulping was observed. The amount of dissolved softwood hemicelluloses in black liquor was significantly increased at the higher [OH-] level and even further in the presence of PS and AQ. Simultaneously, the formation of hydroxy acids was decreased, indicating a significant stabilization of the dissolved polysaccharide fraction parallel to the pulp polysaccharides.

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

TAPPI Journal ◽  
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.

Prehydrolysis kraft pulping of jute cutting and caddis mixture for rayon production

TAPPI Journal ◽  
2019 ◽  
Vol 18 (5) ◽  
pp. 287-293 ◽  
Author(s):  
JANNATUN NAYEEM ◽  
M. SARWAR JAHAN ◽  
RAZIA SULTANA POPY ◽  
M. NASHIR UDDIN ◽  
M.A. QUAIYYUM
Keyword(s):  
Kraft Pulping ◽  
Kappa Number ◽  
Pulp Yield ◽  
Solid Residue ◽  
Rayon Production ◽  
Kraft Cooking ◽  
Prehydrolysis Kraft

Jute cutting, jute caddis, and cutting-caddis mixtures were prehydrolyzed by varying time and temperature to get about 90% prehydrolyzed yield. At the conditions of 170°C for 60 min of prehydrolysis, the yield for 100% jute cutting was 76.3%, while the same for jute caddis was only 67.9%. But with prehydrolysis at 150°C for 60 min, the yield was 90% for jute cutting, where 49.94% of original pentosan was dissolved and prehydrolysis of jute caddis at 140°C in 60 min yielded 86.4% solid residue. Jute cutting-caddis mixed prehydrolysis was done at 140°C for 30 min and yielded 92% solid residue for 50:50 cutting-caddis mixtures, where pentosan dissolution was only 29%. Prehydrolyzed jute cutting, jute caddis, and cutting-caddis mixtures were subsequently kraft cooked. Pulp yield was only 40.9% for 100% jute cutting prehydrolyzed at 170°C for 60 min, which was 10.9% lower than the prehydrolysis at 140°C. For jute cutting-caddis mixed prehydrolysis at 140°C for 45 min followed by kraft cooking, pulp yield decreased by 3.3% from the 100% cutting to 50% caddis in the mixture, but 75% caddis in the mixture decreased pulp yield by 6.7%. The kappa number 50:50 cutting-caddis mixture was only 11.3. Pulp bleachability improved with increasing jute cutting proportion in the cutting-caddis mixture pulp.

Temperature dependence of germinability of wheat (Triticum aestivum L.) grain in relation to pre-harvest sprouting

1984 ◽  
Vol 35 (2) ◽  
pp. 115 ◽  
Author(s):  
DJ Mares
Keyword(s):  
Dry Weight ◽  
Complete Removal ◽  
Triticum Aestivum L ◽  
Treatment Temperature ◽  
Preharvest Sprouting ◽  
Optimum Temperature ◽  
Grain Dormancy ◽  
Lag Period ◽  
Pre Treatment ◽  
Damage Tolerant

Germinability in harvest-mature wheat grain showed a marked dependence on temperature. The optimum temperature for the complete germination of all grains ranged from 20�C for the non-dormant variety, Timgalen, to 10�C for the strongly dormant red wheat RL 4137, whereas the optimum in terms of the shortest lag period ranged from 25� to 15�C for the same varieties. Germinability gradually increased during post-harvest storage and, for after-ripened grain, the optimum temperature for both complete germination and shortest lag period were greater than 30�C. Germinability could also be increased by pre-treating imbibing grains at temperatures of 5�, 10� or in some cases 15�C. This treatment was only effective for grain at moisture contents >25% (dry weight) and the effect was not reversed by redesiccation. The pre-treatment temperature required for maximum germinability decreased with increasing levels of grain dormancy. Complete removal of dormancy required a pre-treatment period of c. 48 h; however, lesser periods gave the shortest lag period in the case of the dormant varieties. The implications of these results for the utilization of dormancy in the development of preharvest sprouting damage tolerant varieties and their subsequent use in practice are discussed.

Kraft pulping and bleaching of Eichhornia crassipes (Mart.) Solms (water hyacinth)

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9243-9264
Author(s):  
Luis Fernando Pintor-Ibarra ◽  
José de Jesús Rivera-Prado ◽  
Sarai Ramos-Vargas ◽  
Teófilo Escoto-García ◽  
Nancy Eloisa Rodríguez-Olalde ◽  
...  
Keyword(s):  
Water Hyacinth ◽  
Eichhornia Crassipes ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Pulp Yield ◽  
Inorganic Elements ◽  
Wood Fibers ◽  
Pulp Bleaching ◽  
Cellulosic Pulp ◽  
Unbleached Pulp

Eichhornia crassipes (water hyacinth) was pulped by means of a kraft pulping process with reagent loads of 10 and 20% on a dry matter basis to determine yield, rejects, kappa number, and ash. Fiber classification, brightness, opacity, and viscosity were measured in the brown pulp. Bleaching was performed by means of an O1O2D1(PO)D2HD3 sequence. Yield, kappa number, pH, ash, brightness, opacity, and viscosity were evaluated in the bleached pulp. Finally, a microanalysis of inorganic elements was carried out in both the bleached and unbleached pulp ash. The highest kraft pulp yield was 26.4%, with a 10% reagent load at 120 °C and 30 minutes cooking. It was determined that E. crassipes cellulosic pulp contains large amounts of fines. Results of the bleaching sequence indicate low brightness (58.0 %) and low viscosity (6.43 cP). The most abundant inorganic elements in the ash of both bleached and unbleached pulp were Ca, Mg, P, and Si. These results suggest that E. crassipes biomass might complement cellulosic fibers in pulping processes of low yield, such as the wood fibers used to produce handmade paper.

A Novel Ethanol-Based Non-Particulate Ink for Spin-Coating Cu2ZnSnS4 Thin Film

2021 ◽  
Vol 16 (2) ◽  
pp. 136-141
Author(s):  
Jingyuan Zhang ◽  
Yusheng Liu ◽  
Jianing Song ◽  
Mu Zhang ◽  
Xiaodong Li
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Spin Coating ◽  
Treatment Temperature ◽  
Coated Film ◽  
Coating Method ◽  
Pre Treatment ◽  
Cu2znsns4 Thin Film ◽  
Czts Thin Films

The Cu2ZnSnS4 (CZTS) thin films were fabricated by the direct solution coating method using a novel non-particulate ink. The ink was formulated using ethanol as the solvent and 1,2-diaminopropane as the complex-ing agent. The pure phase kesterite films with good crystallinity, large-sized crystals and excellent electrical properties were prepared by the spin-coating deposition technique using the homogeneous and air-stable ink. It was found that the subsequent pre-treatment temperature had an influence on the film crystallinity and electrical properties. The best film was obtained by pre-treating the spin-coated film at 250 °C, and then post-annealing at 560 °C. The film shows a narrow bandgap of 1.52 eV and excellent electrical properties, with a resistivity of 0.07 Ocm, carrier concentration of 3.0 x 1017 cm-3, and mobility of 4.15 cm2 V-1 s-1. The novel non-particulate ink is promising for printing high quality CZTS thin films as absorber layers of thin film solar cells.

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.

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.

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