Chemistry of Pulp Bleaching

2010 ◽  
pp. 393-438 ◽  
Author(s):  
Göran Gellerstedt
Keyword(s):  
Pulp Bleaching

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

TAPPI Journal ◽  
2013 ◽  
Vol 12 (10) ◽  
pp. 33-41 ◽  
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.

A Report on 2008 International Pulp Bleaching Conference

2008 ◽  
Vol 62 (9) ◽  
pp. 1147-1155
Author(s):  
Tomoya Yokoyama ◽  
Koki Kisara ◽  
Iori Tomoda ◽  
Kazuhiro Kurosu ◽  
Shiho Katsukawa ◽  
...  
Keyword(s):  
Pulp Bleaching

Trend of Pulp Bleaching Research in Oji Paper

2011 ◽  
Vol 65 (9) ◽  
pp. 866-872
Author(s):  
Makoto Iwasaki
Keyword(s):  
Pulp Bleaching

Formation of organochlorine compounds in kraft pulp bleaching processes

Chemosphere ◽  
1996 ◽  
Vol 33 (12) ◽  
pp. 2431-2440 ◽  
Author(s):  
S. Juuti ◽  
T. Vartiainen ◽  
J. Ruuskanen
Keyword(s):  
Kraft Pulp ◽  
Organochlorine Compounds ◽  
Pulp Bleaching ◽  
Kraft Pulp Bleaching

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.

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