Chapter 4. Chemical pulp bleaching

Abstract Bagasse fiber has been used in the production of bleached chemical pulp by the Pars Paper Company. In this company, a conventional three-stage sequence of hypochlorite, alkaline extraction and second hypochlorite (HEH) is applied in pulp bleaching. Pulp bleaching is one of the most important environmental pollutant stages in the pulp and paper industry. In this research, the bleaching of soda bagasse pulp by applying Oxone and TAED-activator in non-chlorine bleaching sequences has been investigated. The unbleached pulp, with kappa number of 20, 955 ml/g viscosity and 37 % brightness, was prepared from Pars Paper Company. Results indicated that, the TAED at the first and second stages were more effective than in the Oxone stages. Moreover, the sequences, which contained TAED- and Oxone-second-stage, could reach the minimum level of kappa (1.7), but the highest brightness (80 %) was attained by using only TAED with a comparatively high level of pulp viscosity (752).

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Hydrogen Peroxide Bleaching. New Application of Hydrogen Peroxide in Chemical Pulp Bleaching.

JAPAN TAPPI JOURNAL ◽

10.2524/jtappij.52.623 ◽

1998 ◽

Vol 52 (5) ◽

pp. 623-629 ◽

Cited By ~ 1

Author(s):

Tetsuo Koshitsuka

Keyword(s):

Hydrogen Peroxide ◽

Pulp Bleaching ◽

Peroxide Bleaching ◽

Chemical Pulp

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Modelling of chemical pulp bleaching

Nordic Pulp & Paper Research Journal ◽

10.3183/npprj-2008-23-01-p091-101 ◽

2008 ◽

Vol 23 (1) ◽

pp. 91-101 ◽

Cited By ~ 6

Author(s):

Ville Tarvo ◽

Susanna Kuitunen ◽

Tuula Lehtimaa ◽

Pekka Tervola ◽

Erkki Räsänen ◽

...

Keyword(s):

Pulp Bleaching ◽

Chemical Pulp

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Inclusion of a pressurized acidolysis stage in chemical pulp bleaching

BioResources ◽

10.15376/biores.6.1.823-840 ◽

2011 ◽

Vol 6 (1) ◽

pp. 823-840

Author(s):

Samar K. Bose ◽

Aaron Leavitt ◽

Bertil Stromberg ◽

Dipankar Kanungo ◽

Raymond C. Francis

Keyword(s):

Kraft Pulp ◽

Model Compound ◽

Lignin Content ◽

Control Sample ◽

Major Change ◽

Pulp Yield ◽

Pulp Bleaching ◽

Lignin Model Compound ◽

Chemical Pulp ◽

Lignin Model

Hardwood soda-AQ pulps are believed to be rich in benzyl sugar ethers (BSE) that can be partially cleaved by aqueous acidic treatments. The aim of this investigation was to evaluate the effect of acidolysis on final bleached brightness for kraft and soda-AQ (SAQ) hardwood pulps. The increase in final brightness due to acidolysis at 110 °C was twice as high for a eucalyptus SAQ pulp as compared to the kraft pulp. An oxygen delignified maple C-SAQ pulp (carbonate pre-treated SAQ) was acidolyzed at 120 °C and pH 2.6 for 30 min. When 1.60% ClO2 + 0.25% H2O2 on pulp was used in DEPD final bleaching of the control sample a brightness of 91.5% was achieved. When only 1.00% ClO2 + 0.25% H2O2 on pulp was used for the acidolyzed sample a brightness of 92.0% was attained. Analyses of the maple pulp after the acidolysis showed no major change in lignin content, brightness, or pulp yield. The minor changes suggest that a facile reaction such as benzyl ether cleavage was responsible for the improved bleachability. Preliminary research involving a lignin model compound and commercial birch xylan showed that lignin-carbohydrate condensation products were generated under SAQ cooking conditions. Furthermore, a fraction of these lignin-carbohydrate moieties were subsequently cleaved by acidolysis at pH 2.5 and 105 °C.

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ENVIRONMENTALLY FRIENDLY TECHNIQUES FOR CHEMICAL PULP BLEACHING

Environmental Engineering and Management Journal ◽

10.30638/eemj.2010.011 ◽

2010 ◽

Vol 9 (1) ◽

pp. 73-80 ◽

Cited By ~ 1

Author(s):

Dan Gavrilescu ◽

Grigore Craciun ◽

Gheorghe Dutuc ◽

Alexandru Botar ◽

Adrian Catalin Puitel

Keyword(s):

Environmentally Friendly ◽

Pulp Bleaching ◽

Chemical Pulp

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Coagulation of wood extractives in chemical pulp bleaching filtrate by cationic polyelectrolytes

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2007.08.084 ◽

2008 ◽

Vol 153 (1-2) ◽

pp. 525-531 ◽

Cited By ~ 10

Author(s):

T. Leiviskä ◽

J. Rämö

Keyword(s):

Pulp Bleaching ◽

Wood Extractives ◽

Chemical Pulp ◽

Cationic Polyelectrolytes

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Elemental chlorine-free bleaching of North American hardwood kraft pulps: Evaluation of oxidant-reinforced extraction variables on overall bleaching optimization

TAPPI Journal ◽

10.32964/tj12.10.33 ◽

2013 ◽

Vol 12 (10) ◽

pp. 33-41 ◽

Cited By ~ 4

Author(s):

BRIAN N. BROGDON

Keyword(s):

Response Surface ◽

Chlorine Dioxide ◽

North American ◽

Yield Loss ◽

Alkaline Extraction ◽

Kraft Pulps ◽

Pulp Bleaching ◽

Response Surface Models ◽

Elemental Chlorine ◽

Surface Models

This investigation evaluates how higher reaction temperatures or oxidant reinforcement of caustic extraction affects chlorine dioxide consumption during elemental chlorine-free bleaching of North American hardwood pulps. Bleaching data from the published literature were used to develop statistical response surface models for chlorine dioxide delignification and brightening sequences for a variety of hardwood pulps. The effects of higher (EO) temperature and of peroxide reinforcement were estimated from observations reported in the literature. The addition of peroxide to an (EO) stage roughly displaces 0.6 to 1.2 kg chlorine dioxide per kilogram peroxide used in elemental chlorine-free (ECF) bleach sequences. Increasing the (EO) temperature by Δ20°C (e.g., 70°C to 90°C) lowers the overall chlorine dioxide demand by 0.4 to 1.5 kg. Unlike what is observed for ECF softwood bleaching, the presented findings suggest that hot oxidant-reinforced extraction stages result in somewhat higher bleaching costs when compared to milder alkaline extraction stages for hardwoods. The substitution of an (EOP) in place of (EO) resulted in small changes to the overall bleaching cost. The models employed in this study did not take into account pulp bleaching shrinkage (yield loss), to simplify the calculations.

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