A Method to Reduce Steam Consumption of ECF Bleaching Based on Operation Optimizing
and Lei Zhan 4Round 1
Reviewer 1 Report
The manuscript entitled „ Method to Reduce Steam Consumption of ECF Bleaching based on
Operation Optimizing ” aims to demonstrate the models for steam reduction in pulp production and with mandatory increase of chemicals dosage in order to pulp quality retention. From that point of view (from my point of view) or form environmental point of view, it is not acceptable. The scientific contribution would be to reduce steam and to reduce (or to keep previous) dosage of chemicals. This paper is more technical paper than Scientific paper.
The manuscript is not prepared according to Journal requirements. The in line reference citations and reference list should be set according to journal requirements. The manuscript should be prepared in given Journal template.
Line 25: 404 million with space between
Line 39: Costa A et al. Proposed – use the Journal reference guideline (this refers to all reference citations in the whole manuscript, not just this example)
Line 43: Goortani B M et al. will integrate – I think they have integrated it…
Line 48: K2S2O8 – use the full name not just chemical formula
Lines 48-49: Some researchers – Use more adequate adjectives since you have stated only one reference, not few of them…
Line 85: would be increased – should be increased
Line 87: eucalyptus kraft pulp – is there any Latin name for the used pulp
Line 91: The initial conditions were… - the initial conditions of pulp were
Line 113 : Figure 2 is too blurred, the Figure should be given in better quality
Lines 120-121: Considering the Kappa number after bleaching is small and testing method which difficult to judge the end point of titration causes the analysis result unstable. – please check the sentence construction.
Lines 130-131: Please include the equations numbers in text
(after 10 page the line numbering is missing)
Figure 3 Is to blurred. Should be replaced with high quality
Increasing the amount of chemicals to ensure the quality of the pulp and reducing the
bleaching temperature to reduce steam consumption and the cost of bleaching. – what about the sustainability issues related to increased usage of chemicals?
Moreover, is there any other benefit from this steam reduction?
Author Response
Dear reviewer,
Thank you for giving us an opportunity to modify our manuscript. Here, please allow us to express our thanks to you.We carefully considered all the opinions of the reviewers and completed a major revision according to your guide. The point-to-point response to the comments and the revisions to the paper based on their comments are shown below.
The manuscript entitled “Method to Reduce Steam Consumption of ECF Bleaching based on Operation Optimizing” aims to demonstrate the models for steam reduction in pulp production and with mandatory increase of chemicals dosage in order to pulp quality retention. From that point of view (from my point of view) or form environmental point of view, it is not acceptable. The scientific contribution would be to reduce steam and to reduce (or to keep previous) dosage of chemicals. This paper is more technical paper than Scientific paper.
Thank you for your professional reviews. We agree with you very much that the consumption of steam and the utilization of chemicals can be reduced simultaneously is the most appropriate from the perspective of environmental protection. However, it is contradictory to achieve pulp bleaching quality. From our previous research, brightness decreases as the decrease of bleaching temperature and chemical dosage. It means that reducing the consumption of steam will reduce the whiteness of the product, to keep the production capacity, the dosage of chemicals should be increased to make up for the reduction of whiteness. As mentioned in the revised manuscript, the steam consumption is reduced by 19.45% after optimization, and the total production cost is reduced by 1.62%, but the consumption of chemicals is only increased by 1.69%; less than 5% of waste water in the pulp and paper mills are affected by this chemical, which has little effect on the total pollutants. Moreover, as the reduction of steam consumption, air pollution of combusting coal can be reduced. How to realize the optimization of bleaching cost, pulp quality and total environmental impact is the objective of our following research. I'm very sorry for the inconvenience caused by the improper expression. We have made major revises to the structure of the article, hoping that the revised version will become more reasonable. Thank you again for your professional comments.
1. The manuscript is not prepared according to Journal requirements. The in line reference citations and reference list should be set according to journal requirements. The manuscript should be prepared in given Journal template.
Thank you for your carefully reviewing, it is our mistake that there is a gap between the format of the paper and the requirements of the journal. We have modified the references in the article according to the requirements of the journal, and the revised references will be more suitable for the publication requirements of the journal.
2. Line 25: 404 million with space between
Thank you for your carefully reviewing, due to our carelessness, the space between 404 and million was lost. The same errors also were modified and annotated in the revised manuscript.
3. Line 39: Costa A et al. Proposed – use the Journal reference guideline (this refers to all reference citations in the whole manuscript, not just this example).
Thank you for your professional advice. We apologize for the poor experience caused by incorrect use of names. All names in the article have been modified accordingly as required.
4. Line 43: Goortani B M et al. will integrate – I think they have integrated it…
Thank you for your detailed reviews. I am sorry that the misunderstanding of the work of related researchers caused by our mistakes in writing. We have modified the tense of this sentence to make it look more fluent and reasonable.
5. Line 48: K2S2O8 – use the full name not just chemical formula.
Thank you for your professional reviews. I am sorry for not providing the full name of the chemical abbreviation when it first appeared. We have added the full chemical name of K2S2O8 to the paper.
6. Lines 48-49: Some researchers – Use more adequate adjectives since you have stated only one reference, not few of them…
Thank you for your comments. We have used the author’s name here to explain the work he has done, which will make it look more reasonable.
7. Line 85: would be increased – should be increased.
Thank you for your carefully reviewing. We deleted this content according to the comments of other reviewers.
8. Line 87: eucalyptus kraft pulp – is there any Latin name for the used pulp.
Thank you for your comments. According to your suggestion, we tried to find a Latin name of eucalyptus kraft pulp. But after searching related documents and dictionaries, we found that we could not find a word to describe eucalyptus kraft pulp more reasonably.
9. Line 91: The initial conditions were… - the initial conditions of pulp were.
Thank you for your carefully reviewing. Obviously, your sentence is more reasonable for the content of the article. We have revised this sentence as required.
10. Line 113: Figure 2 is too blurred, the Figure should be given in better quality.
Thank you for your comments. I apologize for such an error. We have changed the picture to make it look clearer.
11. Lines 120-121: Considering the Kappa number after bleaching is small and testing method which difficult to judge the end point of titration causes the analysis result unstable. – please check the sentence construction.
Thank you for your professional suggestion. I apologize for such a grammatical error. We have reviewed the sentence structure again and revised it.
12. Lines 130-131: Please include the equations numbers in text.
Thank you for your professional advice. Combined with the opinions of other reviewers, we have adjusted the structure of the paper. The source of each equation was explained in the adjusted article, and the corresponding equation number was added to the analysis.
13. (after 10 page the line numbering is missing)
Thank you for your carefully reviewing. I ' m sorry that my carelessness caused such a format error, the line number disappeared has been added in the revision.
14. Figure 3 Is to blurred. Should be replaced with high quality
Thank you for your comments. I apologize for such an error. We have changed the figure to make it clearer.
15. Increasing the amount of chemicals to ensure the quality of the pulp and reducing the bleaching temperature to reduce steam consumption and the cost of bleaching. – what about the sustainability issues related to increased usage of chemicals? Moreover, is there any other benefit from this steam reduction?
Please allow us to express our thanks for your careful review and detail guides. As you said, in our optimization strategy, we lowered the bleaching temperature to reduce steam consumption, while increasing the dosage of chemicals to maintain the quality of the pulp. Increasing the dosage of chemicals will have a sustainability issues on the environment. But we have found that the concentration of wastewater discharged from the bleaching process accounts for 5% of the mixed wastewater of the paper mill (calculated based on the chemical oxygen demand (COD) in the wastewater). So, the treatment cost caused by this part can be ignored. Reducing the consumption of steam can reduce the amount of fuel used, thereby reducing the emission of harmful gases such as sulfur dioxide (SO2) in industrial production, which has obvious benefits to the environment. These research results is the basis for the following multi-objective optimization of pulp quality, environmental impacts and bleaching cost in the bleaching process，which is the objective of our following research.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I would apprecaite the scientific discussion in your conclusions.
Weaknesses of experiment and model should be described.
Some small remarks in the text.
Comments for author File: Comments.pdf
Author Response
Dear reviewer,
Thank you for giving us an opportunity to modify our manuscript. Here, please allow us to express our thanks to you.We carefully considered all the opinions of the reviewers and completed a major revision according to your guide. The point-to-point response to the comments and the revisions to the paper based on their comments are shown below.
1. In the introduction, some people's names are quoted incorrectly.
Thank you for your detailed reviews. We have modified the format of the author's name one by one through after deleting the author's last name.
2.No space is required between 8 and %.
Thank you for your carefully reviewing, we have deleted the spaces, the same errors also were modified and annotated in the revised manuscript.
3. ECF did not list the full name when it appeared first time.
We are very sorry for this mistake; the full name is added in the revised manuscript.
4. Figures 1 and 2 do not indicate the source.
Thank you for your professional advice. The Schematic diagram of a typical bleaching system shown in Figure 1 was drawn by us with reference to the bleaching process of relevant enterprises. Also, Fig. 2 is the block diagram of the bleaching system drawn on the basis of Fig. 1, so the source is not need to mark.
5. Line number disappears after line 204.
Thank you for your comments. I ' m sorry that my carelessness caused such a format error, the line number disappeared has been added in the revision.
6. The picture quality in Fig. 3 is poor.
Thank you for your comments. We have replaced Figure 3 with the clearer pictures.
Also, other similar errors have been revised.
Other comments.
I would appreciate the scientific discussion in your conclusions. Weaknesses of experiment and model should be described.
Thank you for your professional advice. According to your suggestion, we discussed the other functions of the optimization model besides reducing steam consumption in the conclusion of the revised paper, and elaborated the further research based on this study. At the same time, the weaknesses and its causes are described. In order to solve the issues or improve the situation, the problems need to be solved or technologies should to be developed are expounded in the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
Review of “A Method to Reduce Steam Consumption of 1 ECF Bleaching based on Operation Optimizing” by Chen et al.
I found this manuscript hard to follow; both due to numerous grammatical errors, and due to the methodology and analysis/discussion not being clearly expressed. I have highlighted below my main areas of concern.
On lines 84-85 the authors say “In consequence, steam consumption can be reduced by decreasing bleaching temperature, but some chemicals dosages would be increased to ensure pulp quality and control bleaching cost.” However, they have presented no evidence as to what the effect of reducing bleaching temperature would be, or that any effect could be overcome by increasing the chemical levels.
Equation (4) is the conservation of energy equation, as the authors state, but the implication is that equation (5) is also a conservation of energy equation, which it is not. The authors need to explain the format of equation (5), including references to other work where applicable.
Equation (10) relates to minimising the function in equation (5). The value of all the variable in this equation are set out after equation (5) in the text, with the exception of T_{out,i}. None of the parameters in equation (11) appear in equation (10), so it is not clear how the constraints are applied, or how equation (11) can be minimised, other than changing the output temperature. The authors need to clearly set out what they are doing.
In figure 3, it is unclear how the calculated values of Kappa, viscosity and brightness were calculated.
In the conclusions, the authors make the point that the steam has been reduced by 19.45%, which appears to be a good saving in terms of energy; however in the abstract the reduction in cost is 1.62%. Given that this is the most energy-intensive industry (line 26), the small decrease in cost relative would suggest a significant increase in the cost of the chemicals suggesting a considerable larger mass of chemical is being used. Could the authors quantify this and comments on the environmental effects of this relative of the environmental benefits of using less energy. They should also make it clear in the conclusions that the cost saving is only 1.62%
Author Response
Dear reviewer,
Thank you for giving us an opportunity to modify our manuscript. Here, please allow us to express our thanks to you.We carefully considered all the opinions of the reviewers and completed a major revision according to your guide. The point-to-point response to the comments and the revisions to the paper based on their comments are shown below.
Review of “A Method to Reduce Steam Consumption of ECF Bleaching based on Operation Optimizing” by Chen et al. I found this manuscript hard to follow; both due to numerous grammatical errors, and due to the methodology and analysis/discussion not being clearly expressed. I have highlighted below my main areas of concern.
1. On lines 84-85 the authors say “In consequence, steam consumption can be reduced by decreasing bleaching temperature, but some chemicals dosages would be increased to ensure pulp quality and control bleaching cost.” However, they have presented no evidence as to what the effect of reducing bleaching temperature would be, or that any effect could be overcome by increasing the chemical levels.
Thank you for your professional advice. This expression lacks logic, also no evidence presented. Our previous work found that the brightness of pulp increases as the dosage of chemicals increases, and the brightness of pulp decreases when the bleaching temperature declines. So, the description has been updated in the revised version.
2. Equation (4) is the conservation of energy equation, as the authors state, but the implication is that equation (5) is also a conservation of energy equation, which it is not. The authors need to explain the format of equation (5), including references to other work where applicable.
Thank you for your comments. I am sorry for the misunderstanding caused by the improper expression. In order to improve the logic of the text, the equations (4) and (5) (equations (1) and (2) in revised manuscript) are elaborated separately in the revised manuscript. The description about the meaning of equation 5 and related reference are added.
3. Equation (10) relates to minimizing the function in equation (5). The value of all the variable in this equation are set out after equation (5) in the text, with the exception of Tout,i. None of the parameters in equation (11) appear in equation (10), so it is not clear how the constraints are applied, or how equation (11) can be minimised, other than changing the output temperature. The authors need to clearly set out what they are doing.
Thank you for your professional suggestion. I am very sorry for the error that the logic of the original article was not clear enough. We have adjusted the structure of the article to make it more logical and clearly. The logic of text is expressed as follows. We first established the calculation equation of steam consumption, and put forward the objective function and the main factors that affect the objective function. Then, the constraints of the optimization model combine the original pulp quality calculation model and bleaching cost calculation model in sections 2.3.2.
4. In figure 3, it is unclear how the calculated values of Kappa, viscosity and brightness were calculated.
Thanks for your professional suggestion, it is a mistake in our work. Firstly, the functions of pulp quality indices (pulp brightness, viscosity and Kappa number) and operating conditions are obtained by data fitting based on a large number of single factor experiments on each stage. Then, the quality indices after bleaching can be calculated by utilizing equations (4) – (6) and quality indices models of each stage in table 3 based on the obtained initial value of pulp brightness, the amount of bleaching chemicals, the bleaching temperature of each stage. The corresponding description has been updated in the revised version.
5. In the conclusions, the authors make the point that the steam has been reduced by 19.45%, which appears to be a good saving in terms of energy; however, in the abstract the reduction in cost is 1.62%. Given that this is the most energy-intensive industry (line 26), the small decrease in cost relative would suggest a significant increase in the cost of the chemicals suggesting a considerable larger mass of chemical is being used. Could the authors quantify this and comments on the environmental effects of this relative of the environmental benefits of using less energy. They should also make it clear in the conclusions that the cost saving is only 1.62%.
Please allow us to express our thanks for your careful review and detail guides. As you said, in our optimization strategy, we really need to increase the dosage of chemicals to compensate for the decrease in brightness due to the reduction in steam consumption. However, the dosage of chemicals before and after optimization is increased by 1.69%, and the concentration of wastewater discharged from the bleaching process accounts for 5% of the mixed wastewater of the paper mill (calculated based on the chemical oxygen demand (COD) in the wastewater). Therefore, the treatment cost caused by this part can be ignored. And our optimization goal is to reduce the steam consumption in the bleaching process as much as possible under the premise of ensuring the pulp quality without increasing the bleaching cost, the reduction of steam consumption will reduce the consumption of coal, and to a certain extent will reduce the pollution of the atmosphere from coal combustion. Of course, how to use mathematical programming to achieve multi-objective optimization that takes into account the cost and pollutant emissions of the bleaching process, and pulp quality is also our future research focus. At the same time, only 1.62% of the cost saving is added in the conclusions.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors have corrected the issues I have stated in the first review.
Reviewer 3 Report
The authors address my points in an appropriate manner and I feel the manuscript is suitable for publication.
