scholarly journals CHLORINE DIOXIDE BLEACHING OF PULP FROM CROP RESIDUES: BAGASSE, KASH AND CORN STALKS

2021 ◽  
Vol 55 (3-4) ◽  
pp. 281-287
Author(s):  
TASLIMA FERDOUS ◽  
MD. IMRAN HOSSAIN ◽  
MOUMITA NANJIBA ◽  
M. A. QUAIYYUM ◽  
M. SARWAR JAHAN
Keyword(s):  
Chlorine Dioxide ◽  
Crop Residues ◽  
Corn Stalk ◽  
Alkaline Extraction ◽  
Effluent Quality ◽  
Pulp Viscosity ◽  
Pulp Properties ◽  
Effluent Discharge ◽  
Ecf Bleaching ◽  
Bagasse Pulp

"This investigation describes the effect of hot chlorine dioxide delignification (DHT) of bagasse, kash and corn stalk pulps on pulp properties and effluent quality. The pulps were subjected to DHT at 85 °C for 45 min and the results were compared with those of the D0 process carried out at 70 °C for 45 min. The kappa numbers after the alkaline extraction (Ep) stage in DHT bleaching were always lower and brightness was higher, compared to the corresponding parameters in D0 bleaching, without impacting pulp viscosity. The final brightness of the corn stalk pulp was 84.8% at a kappa factor of 0.25 in the D0 process, while in the DHT process, the same type of pulp reached the brightness of 87.2% at a kappa factor of 0.15, saving 40% ClO2 in the first stage. Similarly, kash pulp exhibited 90% brightness at a kappa factor of 0.15, which also saved 40% ClO2, compared to the conventional D0 process. The brightness of bagasse pulp in DHT and D0 processes was almost similar. Oxygen delignified pulp had a lower effluent discharge than unbleached pulps in subsequent ECF bleaching. The COD value in DHT was lower than that in D0."

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 ECF Bleaching with Molybdenum Activated Acid Peroxide and its Impact on Eucalyptus Pulp Properties and Effluent Quality

2011 ◽  
Vol 02 (01) ◽  
pp. 61-70
Author(s):  
Marco Antônio Bandeira Azevedo ◽  
Vânya Márcia Duarte Pasa ◽  
Hannu Hämäläinen ◽  
Ann Honor Mounteer ◽  
Rubens Chaves de Oliveira ◽  
...  
Keyword(s):  
Effluent Quality ◽  
Eucalyptus Pulp ◽  
Pulp Properties ◽  
Ecf Bleaching

scholarly journals Enzymes improve ECF bleaching of pulp

BioResources ◽  
2006 ◽  
Vol 1 (1) ◽  
pp. 34-44 ◽  
Keyword(s):  
Chlorine Dioxide ◽  
Acid Treatment ◽  
Kraft Pulp ◽  
Elemental Chlorine ◽  
Eucalyptus Kraft Pulp ◽  
Mediator System ◽  
Pulp Properties ◽  
Laccase Enzyme ◽  
Ecf Bleaching ◽  
Appreciable Reduction

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. A n appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction in chlorine dioxide consumption was obtained when the same laccase treated pulp was subjected to an acid treatment after the extraction stage followed by the DE P D sequence. Elemental-chlorine free bleaching was also performed using the xylanase-laccase treated pulp. Xylanase treatment was incorporated to the laccase mediator system in the elemental-chlorine free bleaching both sequentially and simultaneously. The bleaching sequence DE P D followed and in both the cases, the reduction in chlorine dioxide consumption was greater in comparison to the control. The chlorine dioxide consumption was reduced further when xylanase-laccase treated pulp was given an additional acid treatment. The final pulp properties of the treated pulps were comparable to the control pulp.

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.

Application of pure, thermostable, alkali-tolerant xylanase in bleaching of oxygen-delignified pine kraft pulp

TAPPI Journal ◽  
2015 ◽  
Vol 14 (11) ◽  
pp. 689-694
Author(s):  
QINGZHI MA ◽  
QI WANG ◽  
CHU WANG ◽  
NIANJIE FENG ◽  
HUAMIN ZHAI
Keyword(s):  
Intrinsic Viscosity ◽  
Chlorine Dioxide ◽  
High Purity ◽  
Kraft Pulp ◽  
Alkaline Media ◽  
Industrial Scale ◽  
Elemental Chlorine ◽  
Effect Of Oxygen ◽  
Alkaline Tolerant ◽  
Ecf Bleaching

The effect of oxygen (O2)-delignified pine kraft pulp pretreatment by high-purity, thermostable, and alkaline-tolerant xylanases on elemental chlorine free (ECF) bleaching of O2-delignification kraft pulp was studied. The study found that xylanase pretreatment preserved the intrinsic viscosity and yield of O2-delignified pulp while causing about 7% of delignification with high delignification selectivity. The xylanases with high purity, higher thermostability (75°C~80°C) in highly alkaline media (pH 8.0~9.5) could be applied on an industrial scale. Pulp pretreatment by the high-purity, thermostable, and alkaline tolerant xylanases could improve pulp brightness or reduce the chlorine dioxide (ClO2) consumption. In a D0ED1D2 bleaching sequence using the same amount of ClO2, the xylanase-pretreated pulp obtained a higher brightness (88.2% vs. 89.7% ISO) at the enzyme dose of 2 U/g pulp; or for the same brightness as control (88.2% ISO), the ClO2 dosage in the D0 stage was reduced by 27%, which represents a 16% savings in total ClO2 used for bleaching.

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp • part 2: economic analysis of chemical and steam consumption

TAPPI Journal ◽  
2010 ◽  
Vol 9 (9) ◽  
pp. 47-53 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Chlorine Dioxide ◽  
Previous Investigation ◽  
Kraft Pulp ◽  
Energy Costs ◽  
Alkaline Extraction ◽  
Stage Versus ◽  
Kraft Pulps ◽  
Steam Consumption ◽  
Elemental Chlorine ◽  
Softwood Kraft Pulp

Our previous investigation [1] re-analyzed the data from Basta and co-workers (1992 TAPPI Pulping Conference) to demonstrate how oxidative alkaline extraction can be augmented and how these changes affect chlorine dioxide consumption with elemental chlorine-free (ECF) sequences. The current study manipulates extraction delignification variables to curtail bleaching costs with a conventional U.S. Southern softwood kraft pulp. The economic advantages of ~0.35% to 0.65% H2O2 peroxide reinforcement in a 70°C (EOP)-stage versus 90°C (EO)-stage are predisposed to the brightness targets, to short or long bleach sequences, and to mill energy costs. Minimized bleaching costs are generally realized when a 90°C (EO) is employed in D0(EO)D1 bleaching, whereas a 70°C (EOP) is economically advantageous for D0(EOP)D1E2D2 bleaching. The findings we disclose here help to clarify previous ECF optimization studies of conventional softwood kraft pulps.

Reduction of adsorbable organically bound halogens (AOX) formation at near-neutral pH chlorine dioxide bleaching of softwood kraft pulp

Holzforschung ◽  
2020 ◽  
Vol 74 (6) ◽  
pp. 597-604
Author(s):  
Sara Starrsjö ◽  
Olena Sevastyanova ◽  
Peter Sandström ◽  
Juha Fiskari ◽  
Maria Boman ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
High Selectivity ◽  
Bicarbonate Buffer ◽  
Neutral Ph ◽  
Elemental Chlorine ◽  
Pulp Viscosity ◽  
Softwood Kraft Pulp ◽  
New Type ◽  
Adsorbable Organically Bound Halogens

AbstractRecently, a new type of bleaching sequence, Elemental Chlorine Free (ECF) light with one D stage, has been developed. It combines the efficiency and high selectivity of chlorine dioxide (ClO2) bleaching with more environmental friendly oxygen based bleaching chemicals. This work examines the effect of pH on the formation of adsorbable organically bound halogens (AOX) in an intermediate D stage – a single ClO2 stage at the middle of an ECF light bleaching sequence. Carbon dioxide (CO2) is used to generate a bicarbonate buffer in situ, stabilizing the pH during the bleaching. Near-neutral pH is hypothesized to decrease the formation of strongly chlorinating species, so that the AOX formation is reduced. The results indicate that a near-neutral pH D stage can reduce the AOX content in the effluents with up to 30%. The ISO brightness was unchanged to a lower ClO2 consumption. The pulp viscosity was slightly higher after near-neutral pH D stage, but to its disadvantage a lesser delignification and removal of HexA was obtained. The degradation of HexA correlated well with the AOX, affirming earlier theories that HexA has a major impact on the AOX formation. The higher amounts of residual HexA and lignin resulted in more thermal yellowing of the pulps bleached with a near-neutral pH D stage.

Using Oxone and TAED activator in non-chlorine bleaching of soda bagasse pulp

2019 ◽  
Vol 34 (4) ◽  
pp. 422-432
Author(s):  
Farhad Zeinaly ◽  
Konstantin Gabov ◽  
Hadi Kanåni Sula ◽  
Arash Babavand ◽  
Pedro Fardim
Keyword(s):  
Paper Industry ◽  
Environmental Pollutant ◽  
Pulp Bleaching ◽  
Chemical Pulp ◽  
Chlorine Bleaching ◽  
Pulp Viscosity ◽  
Paper Company ◽  
High Level ◽  
Bagasse Fiber ◽  
Bagasse Pulp

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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