Studies on process parameters for chlorine dioxide production using IrO2 anode in an un-divided electrochemical cell

2009 ◽  
Vol 164 (2-3) ◽  
pp. 812-819 ◽  
Author(s):  
K. Chandrasekara Pillai ◽  
Tae Ouk Kwon ◽  
Bo Bae Park ◽  
Il Shik Moon
Keyword(s):  
Process Parameters ◽  
Chlorine Dioxide ◽  
Electrochemical Cell

scholarly journals The current distribution in an electrochemical cell. Part VII. Concluding remarks

2002 ◽  
Vol 67 (4) ◽  
pp. 273-278 ◽  
Author(s):  
Konstantin Popov ◽  
S.M. Pesic ◽  
Predrag Zivkovic
Keyword(s):  
Process Parameters ◽  
Current Distribution ◽  
Current Density ◽  
Electrochemical Cell ◽  
Side Wall ◽  
Cell Geometry ◽  
Electrode Edge ◽  
Side Walls ◽  
In Cells

Anew method for the determination of the ability of an electrolyte to distribute uniformly current density in an electrochemical cell is proposed. It is based on the comparison of the current in cells in which the electrode edges touch the cell side walls with the current in cells with different electrode edge ? cell side wall distances. The effects of cell geometry process parameters and current density are discussed and illustrated using the results presented in the previous papers from this series.

Optimization of the process parameters of an electrochemical cell in the IS process

2005 ◽  
Vol 60 (24) ◽  
pp. 7160-7167 ◽  
Author(s):  
Mikihiro Nomura ◽  
Hiroyuki Okuda ◽  
Seiji Kasahara ◽  
Shin-ichi Nakao
Keyword(s):  
Process Parameters ◽  
Electrochemical Cell

Using RuO2 anode for chlorine dioxide production in an un-divided electrochemical cell

2010 ◽  
Vol 61 (8) ◽  
pp. 2151-2160 ◽  
Author(s):  
K. Chandrasekara Pillai ◽  
Tae Ok Kwon ◽  
Bo Bae Park ◽  
Il Shik Moon
Keyword(s):  
Sodium Chloride ◽  
Chlorine Dioxide ◽  
Electrochemical Cell ◽  
Current Mode ◽  
Feed Solution ◽  
Constant Current ◽  
Sodium Chlorite ◽  
Solution Ph ◽  
On Line ◽  
Set Up

Chlorine dioxide is a well known powerful disinfectant. Although there are several chemical and electrochemical methods developed for on-line chlorine dioxide generation, the details are mostly confined as patents. We studied in this work the electrochemical generation of dissolved chlorine dioxide from an un-buffered solution of sodium chlorite and sodium chloride mixture in an un-divided electrochemical cell set-up with RuO2-coated-Ti anode and Pt-coated-Ti cathode under constant current mode. Various process parameters including feed flow rate (10 to 150 ml/min), feed solution pH (2.3 to 9.4), concentration of sodium chloride (0 to 170 mM), concentration of sodium chlorite (0 to 7.7 mM), and the applied current (100 to 1,200 mA) were optimized. Experiments were conducted by performing single pass experiments, with no circulation. The current efficiency and the power consumption were calculated for the optimized conditions, and compared with IrO2 electrode of our previous investigation.

Electrochemical cell

1998 ◽  
Vol 70 (1) ◽  
pp. 167
Author(s):  
J Coetzer
Keyword(s):  
Electrochemical Cell

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.

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