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.

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.

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp – part 1: impact of oxidative extraction on chlorine dioxide stoichiometry

TAPPI Journal ◽  
2010 ◽  
Vol 9 (8) ◽  
pp. 27-35 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Decision Making ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Alkaline Extraction ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Kraft Pulp Bleaching ◽  
Softwood Kraft Pulp ◽  
Chemical Usage ◽  
Minimize Costs

The present investigation meticulously analyzes how oxidative alkaline extraction can be augmented through process changes, and how these augmentations can be leveraged to optimize chlorine dioxide usage with elemental chlorine-free (ECF) sequences for a conventional softwood kraft pulp. Bleaching data from Basta and co-workers (1992 TAPPI Pulping Conference) are re-examined and re-interpreted in this study. We determined that ~60% to 65% of the overall ClO2 charge should be applied in the D0-stage. Peroxide addition to an (EOP) can replace 0.6 to 2.5 Kg. ClO2 per Kg H2O2. Boosting the (EO) temperature to 80°C is equivalent to a 70°C (EOP) with 0.25% to 0.30% H2O2,whereas a 90°C (EO) is equivalent to 0.50% – 0.75% H2O2 in a 70°C (EOP). The stoichiometric bleaching data from this study can guide decision-making for lowering chemical usage and minimize costs to reach target brightness levels with three- and five-stage sequences.

Modeling and optimization of ultrasound‐assisted cinnamon extraction process using fuzzy and response surface models

2018 ◽  
Vol 42 (2) ◽  
pp. e12978
Author(s):  
Nur Cebi ◽  
Osman Sagdic ◽  
Abdulrahman Mohammed Basahel ◽  
Mohammed Abdullah Balubaid ◽  
Osman Taylan ◽  
...  
Keyword(s):  
Response Surface ◽  
Extraction Process ◽  
Modeling And Optimization ◽  
Response Surface Models ◽  
Surface Models ◽  
Ultrasound Assisted

Optimization of the Global Static and Dynamic Performance of a Vehicle Body by Means of Response Surface Models

2012 ◽  
Author(s):  
Pavlina Mihaylova ◽  
Alessandro Pratellesi ◽  
Niccolò Baldanzini ◽  
Marco Pierini
Keyword(s):  
Response Surface ◽  
Dynamic Performance ◽  
The Body ◽  
Vehicle Body ◽  
Fe Model ◽  
Structural Modifications ◽  
Response Surface Models ◽  
First Choice ◽  
Surface Models ◽  
Body In White

Concept FE models of the vehicle structure are often used to optimize it in terms of static and dynamic stiffness, as they are parametric and computationally inexpensive. On the other hand they introduce modeling errors with respect to their detailed FE equivalents due to the simplifications made. Even worse, the link between the concept and the detailed FE model can be sometimes lost after optimization. The aim of this paper is to present and validate an alternative optimization approach that uses the detailed FE model of the vehicle body-in-white instead of its concept representation. Structural modifications of this model were applied in two different ways — by local joint modifications and by using mesh morphing techniques. The first choice was motivated by the strong influence of the structural joints on the global vehicle performance. For this type of modification the plate thicknesses of the most influent car body joints were changed. In the second case the overall car dimensions were modified. The drawback of using detailed FE models of the vehicle body is that they can be times bigger than their concept counterparts and can thus require considerably more time for structural analysis. To make the approach proposed in this work a feasible alternative for optimization in the concept phase response surface models were introduced. With them the global static and dynamic performance of the body-in-white was represented by means of approximating polynomials. Optimization on such mathematical models is fast, so the choice of the optimization algorithm is not limited only among local-search strategies. In the current study Genetic Algorithm was used to increase the chances for finding better design alternatives. Two different optimization problems were defined and solved. Their final solutions were presented and compared in terms of structural modifications and resulting responses. The approach in this paper can be successfully used in the concept phase as it is fast and reliable and at the same time it avoids the problems typical for concept models.

scholarly journals An Evaluation of Remifentanil-Sevoflurane Response Surface Models in Patients Emerging from Anesthesia

2010 ◽  
Vol 111 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Ken B. Johnson ◽  
Noah D. Syroid ◽  
Dhanesh K. Gupta ◽  
Sandeep C. Manyam ◽  
Nathan L. Pace ◽  
...  
Keyword(s):  
Response Surface ◽  
Response Surface Models ◽  
Surface Models
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