Oxygen Delignification of Bamboo Kraft Pulp with High Kappa Number

2011 ◽  
Vol 239-242 ◽  
pp. 223-226
Author(s):  
Hui Gao ◽  
Huai Yu Zhan
Keyword(s):  
Caustic Soda ◽  
Reaction Temperature ◽  
Kraft Pulp ◽  
Kappa Number ◽  
Optimal Conditions ◽  
Oxygen Delignification ◽  
Lignin Removal ◽  
Bamboo Pulp ◽  
Major Factors ◽  
Two Stages

Bamboo kraft pulp with Kappa number of 25.6 was sampled, and oxygen delignification was applied to bleach these bamboo pulp samples. By investigating yield, Kappa number, viscosity, brightness of pulp, and delignification selectivity, it has been proven that caustic soda dosage and reaction temperature were major factors for oxygen delignification. The optimal conditions for oxygen delignification were proposed as follows: alkali dosage of 3.5% on o.d. pulp-mass, reaction temperature of 85°C, oxygen pressure of 0.6 MPa, and temperature retention time of 80 min. Two stages of oxygen delignification were used and no washing between the two was required. It was found that delignification efficiency and selectivity to lignin-removal were improved significantly. In addition, adding hydroquinone compounds during oxygen delignification can improve the qualities greatly such as higher viscosity and better selectivity of delignification.

Changes in the lignin-carbohydrate complex in softwood kraft pulp during kraft and oxygen delignification

Holzforschung ◽  
2004 ◽  
Vol 58 (6) ◽  
pp. 603-610 ◽  
Author(s):  
Martin Lawoko ◽  
Rickard Berggren ◽  
Fredrik Berthold ◽  
Gunnar Henriksson ◽  
Göran Gellerstedt
Keyword(s):  
Kraft Pulp ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Oxygen Delignification ◽  
Number Range ◽  
Morphological Aspects ◽  
Carbohydrate Complex ◽  
Softwood Kraft Pulp ◽  
Hydrolysis Of

Abstract Three kraft pulps in the kappa number range between 50 and 20 and the same pulps oxygen-delignified to similar lignin contents (kappa approximately 6) were analyzed for lignin-carbohydrate complexes (LCC) by a method based on selective enzymatic hydrolysis of the cellulose, and quantitative fractionation of the LCC. Between 85 and 90% of residual lignin in the unbleached kraft pulp and all residual lignin in the oxygen-delignified pulps were isolated as LCC. Three types of complexes were found; viz., xylan-lignin, glucomannan-lignin-xylan and glucanlignin complexes. After pulping to a high kappa number, most of the residual lignin was linked to xylan. Different delignification rates were observed so that most of the residual lignin was linked to glucomannan when the pulping was extended to a low kappa number. With increasing degree of oxygen delignification, a similar trend in the delignification rates of LCC was observed so that the residual lignin was increasingly linked to glucomannan. Complex LCC network structures seemed to be degraded into simpler structures during delignification. The differences in delignification rates are discussed with reference to the solubility properties and structural differences of LCC, and to morphological aspects of the pulp.

ECF Bleaching of Pre-Hydrolyzed Larix Kraft Pulp for Production of Dissolving Pulp

2013 ◽  
Vol 634-638 ◽  
pp. 386-390
Author(s):  
Zhi Li ◽  
Jun Li ◽  
Jun Xu
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Kappa Number ◽  
Alkaline Extraction ◽  
Polymerization Degree ◽  
Oxygen Delignification ◽  
Elemental Chlorine ◽  
Pulp Properties ◽  
Ecf Bleaching

Elemental Chlorine Free (ECF) bleaching sequence of O1/O2D0EOPD1D2 was adopted to bleach the pro-hydrolyzed Larix kraft pulp, where O1/O2 was two-stage oxygen delignification without interstage treatment, D was chlorine dioxide bleaching, EOP was pressurized alkaline extraction strengthened by hydrogen peroxide. Keeping bleaching temperature and time unchanged, sodium hydroxide charge(NaOH) in O1 stage, chlorine dioxide(ClO2) charge in D0 stage and D2 stage were studied, pulp properties such as brightness, kappa number, alpha-cellulose, pentosan and polymerization degree were measured and compared to establish optimal bleaching conditions. Results show that the optimal charge of NaOH in O1 stage is 2.5%, ClO2 in D0 and D2 stage are 2.5%, 0.6%, and the pulp gained at the optimal bleaching conditions has the properties of 93.9% of alpha-cellulose, 2.60% of pentosan, 375.5 ml/g of viscosity and 86.6%ISO of brightness.

scholarly journals Bleached kraft pulp production from Pinus tecunumanii (Eguiluz e Perry)

2005 ◽  
Vol 29 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Leonel F. Torres ◽  
Roberto Melo ◽  
Jorge Luiz Colodette
Keyword(s):  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Raw Material ◽  
Kraft Pulps ◽  
Optimum Conditions ◽  
Oxygen Delignification ◽  
Bleached Kraft Pulp ◽  
Pinus Tecunumanii ◽  
Pulp Production

The use of 12-year-old Pinus tecunumanii (Eguiluz e Perry) grown in Colombia was evaluated for bleached kraft pulp production. Kraft pulps of kappa number 30 ± 1 were produced, and oxygen delignified and bleached to 90% ISO with ECF processes. The bleached pulps produced under optimum conditions were evaluated with regard to their strength properties. Pinus tecunumanii wood required low effective alkali charge to reach the desired kappa number and the unbleached pulp showed high oxygen delignification efficiency and bleachability when a OD(EO)DED sequence was used. The bleached pulps presented good physical-mechanical properties, which are comparable to those obtained with more traditional pines such as Pinus taeda and Pinus radiata. The results demonstrate that this tropical pine species is a suitable raw material for bleached kraft pulp production

Quantification of lignin-carbohydrate complexes in hardwood pulps, Part 2: Effects of bleaching chemicals

TAPPI Journal ◽  
2015 ◽  
Vol 14 (10) ◽  
pp. 663-670 ◽  
Author(s):  
DAVID J. NICHOLSON ◽  
GUSTAVO V. DUARTE ◽  
ERICKA F. ALVES ◽  
DAVID J. KIEMLE ◽  
AARON T. LEAVITT ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Kappa Number ◽  
Oxygen Delignification ◽  
Bleaching Process ◽  
Lignin Removal ◽  
Dilute Sodium Hydroxide ◽  
Alkaline Conditions

High kappa number kraft and soda-anthraquinone (soda-AQ or SAQ) pulps from sugar maple (Acer saccharum) were investigated to see how the lignin-carbohydrate complexes (LCC) they contained affected lignin removal by oxygen, chlorine dioxide, and hydrogen peroxide. The chlorine dioxide and hydrogen peroxide doses were higher than normal because both pulps had unbleached kappa numbers in the range of 61-62. Only oxygen delignification was investigated with the SAQ pulp. The research focused on the strong lignin-carbohydrate (L-C) linkages only. The pulp carbohydrates were enzymatically degraded and solubilized, thus leaving an enzymatic lignin (EL) residue. The highest concentration of bound sugars (glucan, xylan, arabinan, and galactan) on any of the ELs was <2.1 wt%. Chlorine dioxide (D stage) was investigated at end pHs of 2.1, 2.9, and 4.0, followed by extraction with dilute sodium hydroxide. Lignin oligomers containing bound glucan and arabinan were unreactive and accumulated in the fibers. When oxygen was used to delignify kraft and SAQ pulps by ~50%, only ~10% of the lignin bound arabinan was solubilized. Galacto-lignin complexes were somewhat reactive to oxygen and hydrogen peroxide under alkaline conditions, but less reactive in the D stages. Consistent with literature data, xylo-lignin complexes were reactive toward oxygen and toward the other two oxidants. They do not appear to be major impediments in the bleaching process.

The Kinetics of Oxygen Delignification of Reed Kraft Pulp (I)-Kinetics of Delignification

2011 ◽  
Vol 236-238 ◽  
pp. 1420-1424
Author(s):  
Xiao Feng Pan ◽  
Le Fan Ma ◽  
Qin Qin Qu ◽  
Jia Liang Lan ◽  
Li Hong Tan
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Oxygen Pressure ◽  
Kraft Pulp ◽  
Reaction Order ◽  
Frequency Factor ◽  
Kappa Number ◽  
Alkali Concentration ◽  
Oxygen Delignification ◽  
Kinetics Of

The kinetics of reed kraft pulp oxygen delignification process is studied, suitable kinetics model determined is -dk/dt=Aexp(-E/RT) [OH-]b[PO2]cKa, and the parameters in the model is calculated. The function for estimation of the kappa number at different reaction time is established for the reed kraft pulp oxygen delignification process. The reaction order fitted is 6.72 for delignification (a), 0.87 for alkali concentration (b), and 0.62 for oxygen pressure(c), respectively. The activation energy E is 80.96KJ/mol and frequency factor A 1.5×104.

Effect of Neutral Xylanase Pretreatment on ECF Bleaching of KP Bamboo Pulp with Low Kappa Number

2012 ◽  
Vol 549 ◽  
pp. 260-264
Author(s):  
Jin Bao Li ◽  
Mei Yun Zhang ◽  
Xin Xing Xia ◽  
Yi Juan Liu
Keyword(s):  
Kappa Number ◽  
Residual Lignin ◽  
Color Reversion ◽  
Bleached Pulp ◽  
Lignin Removal ◽  
Bamboo Pulp ◽  
Ecf Bleaching ◽  
Optimum Charge

At present, most of the studies of Xylanase auxiliary bleaching focused on in the alkaline or acid conditions. It was investigated in this paper that Neutral Xylanase had been used to pretreat the oxygen delignified KP bamboo pulp with low kappa number. The effect of Xylanase on the follow-up ECF bleaching was discussed, especially highlighting the principle of the residual lignin removal and improvement of pulp’s brightness. Results showed that the effect of neutral xylanase pretreatment on ECF bleaching of KP bamboo pulp was obvious. The pulp with a higher brightness and brightness stability could be obtained in this way. The optimum charge of xylanase is 0.6IU•g-1, and The brightness of the bleached pulp could reach 87.8%ISO, the color reversion value 0.016, viscosity 764mL•g-1. It was 2.9%ISO higher in brightness, 59mL•g-1 higher in viscosity, but the color reversion value is only 30.2% of the later, compared to the pulp without xylanase pretreatment.

scholarly journals Response surface methodology optimization study on corncob pretreatment: reduction of sodium hydroxide usage and enhancement in pulpzyme HC biobleaching efficiency

Food Research ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 201-213
Author(s):  
T.-K. Tang ◽  
Y.-Y. Lee ◽  
E.-T. Phuah ◽  
C.-P. Tan ◽  
S. Kanagaratnam ◽  
...  
Keyword(s):  
Reaction Time ◽  
Sodium Hydroxide ◽  
Reaction Temperature ◽  
Complex Structure ◽  
Cellulose Fibre ◽  
Kappa Number ◽  
Alkaline Pretreatment ◽  
Lignin Removal ◽  
Optimization Study ◽  
Optimized Conditions

Lignocellulosic rich corncob biomass possesses less complex structure, lignin and pigment content. As compared to wood pulp, it is considered to be a better alternative for the production of cellulose fibre. The present study was conducted to optimize both the alkaline (using sodium hydroxide) and biobleaching (using Pulpzyme HC) pretreatment process of corncob to promote lignin removal and cellulose swelling. It was the aim of this work to achieve mild processing conditions for corncob pretreatment in order to minimize the chemical usage. Results demonstrated that the mild pretreatment approach employed was found to successfully increase cellulose swelling and lignin removal from the corncob biomass. In alkaline pretreatment process, reaction temperature showed to be the most prominent effect in enhancing lignin removal and cellulose swelling as compared to sodium hydroxide concentration and reaction time. RSM optimized conditions for alkaline pretreatment process: 0.5 M NaOH, reaction temperature of 80°C and reaction time of 30 mins manage to increase the sedimentation index (indicate swelling of cellulose) from 0 to 30 and reduce the kappa number (represent lignin removal) from 82 to 32, respectively. Meanwhile, for biobleaching pretreatment using Pulpzyme HC, reaction time play a more significant role than the Pulpzyme HC concentration in promoting lignin removal and increasing cellulose swelling. RSM optimized conditions showed that the kappa number was reduced from 32 to 18 whereas the sedimentation index increased from 30 to 60 when the alkaline pretreated corncob was biobleached with Pulpzyme HC.

Research on Kraft Pulping Delignification of Bamboo (Neosinocalamus)

2011 ◽  
Vol 418-420 ◽  
pp. 2241-2244
Author(s):  
Pei Yi Li ◽  
Mei Yun Zhang ◽  
Xin Xing Xia ◽  
Chun Tao Lin
Keyword(s):  
Fiber Material ◽  
Wide Distribution ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Raw Material ◽  
Maximum Temperature ◽  
Pulp Yield ◽  
Oxygen Delignification ◽  
Local Conditions ◽  
Bamboo Pulp

Bamboo, as a kind of non-wood raw material, has a long, thin fiber with wide distribution and rich abundance in China. Its pulping properties are between softwood and hardwood. Adapting to the Chinese situation, developing bamboo pulp industrialization, according to the local conditions, is an available way to solve the shortage of fiber material for paper-making. Delignification of bamboo (Neosinocalamus) was carried out by conventional kraft and soda pulping under varying conditions to determine the relationships between selected cooking parameters (EA 14~20%, sulfidity 0~40%, maximum temperature 160 and 165°C, and time at maximum temperature 60~110 min) and pulp properties (kappa number and yield). Results indicated that in order to obtain relatively low kappa numbers(17~27), high sulfidity(20~40%) at lower EA(14~16%) increased pulp yield compared to the case of low sulfidity(0~10%) at higher EA(16~18%). Pulp with lower kappa numbers (13~15) and acceptable yield can be obtained at a sulfidity level of 20~30% with 18% EA or at a sulfidity level of 10~30% with 20% EA. Meanwhile, bamboo pulp in this condition not only helps to decrease kappa number in the subsequent oxygen delignification process, but also reduces the cost of chemicals in the bleaching process.

scholarly journals Factors limiting oxygen delignification of kraft pulp

2001 ◽  
Vol 79 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Leonid G Akim ◽  
Jorge Luiz Colodette ◽  
Dimitris S Argyropoulos
Keyword(s):  
Kraft Pulp ◽  
Oxidation Mechanism ◽  
Quantitative Information ◽  
Total Phenolic ◽  
Residual Lignin ◽  
Analytical Pyrolysis ◽  
Oxygen Delignification ◽  
Softwood Kraft Pulp ◽  
Major Factors ◽  
C Nmr

Softwood kraft pulp was subjected to a laboratory one- and three-stage oxygen delignification process. Pulp and liquor samples were collected at different stages of the process with particular attention being paid to the early and late stages. A novel residual lignin isolation method extracted about 65% of the oxidized residual lignins at a purity exceeding 90%. Using this methodology coupled to quantitative 31P NMR, 13C NMR, 2D heteronuclear (HMQC) NMR spectroscopic and analytical pyrolysis techniques allowed a thorough characterization of the residual and solubilized lignin fractions at the various stages of the process. Our conclusions do not point to a single factor as being responsible for the limits confronting oxygen delignification. Amongst the major factors impeding the effectiveness of oxygen delignification are: (i) the accumulation of relatively inert 5,5' biphenyl structures originally present in kraft lignin from dibenzodioxocin ring opening reactions; and (ii) the accumulation of considerably less reactive p-hydroxyphenyl structures. Detailed quantitative information was obtained and discussed in relation to the presence and role of these unreactive phenolic fractions on the residual oxidized lignins. As such we arrived at important conclusions as to why and how these structures remain and accumulate on the fiber. In addition, issues related to the profiles of the total phenolic hydroxyl content of the residual lignins and the remaining arylglycerol β-O-4 structures are discussed.Key words: analytical pyrolysis, biphenyl structures, HMQC, NMR, oxidation mechanism, oxygen delignification, p-hydroxyphenyl moieties, quantitative 13C NMR, quantitative 31P NMR, residual lignin, solubilized lignin, total phenolic hydroxyls.

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