Effects of Shaft Tuyere Parameters on Gas Movement Behavior and Burden Reduction in Oxygen Blast Furnace
Round 1
Reviewer 1 Report
This paper “Effects of Shaft Tuyere Parameters on Gas Movement Behavior and Burden Reduction in Oxygen Blast Furnace” used a cfd model to simulate influence of the shaft tuyere parameters in an oxygen blast, including shaft tuyere position, shaft tuyere diameter and shaft tuyere angles furnace, which is very meaningful. However, there are few flaws in this article.
(1) The Fig.1 is a bit misty. The mesh and the size of the shaft is hard to recognize. please instead it with a clearer one;
(2) The H2 and the N2 in Table 5 should be subscripted;
(3) Please check the format of the tables and figures in this paper to avoid the errors like question(2);
(4) Was the gas inlet a mass-inlet or a velocity inlet? Please give detailed boundary conditions of this model, including the gas inlet, gas outflow. solid inlet and solid outflow;
(5) Why the different diameters did showed few influence on the distribution of CO mole fraction in shaft in Fig 12? Please provide the opinion of author about this phenomenon.
(6) What’s the convergence criterion of this model? How to judge weather the model has reached steady state? Please give a detailed introduction in paper;
(7) Does this research result provide any help or experience for the iron-making process with oxygen blast furnace?
(8) Besides the temperature and gas conpontents distribution, the production of pig iron, the coke ratio and the coal ratio are important for iron-making process. Did the author consider those indexs?
Comments for author File: 
Comments.pdf
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
1.Comments: The Fig.1 is a bit misty. The mesh and the size of the shaft is hard to recognize. please instead it with a clearer one.
Response: Thanks for your review. This figure has been instead by a clear one.
2.Comments: The H2 and the N2 in Table 5 should be subscripted.
Response: Thanks for your review! Those formal errors in table 5 has been corrected.
3.Comments: Please check the format of the tables and figures in this paper to avoid the errors like question(2);.
Response: Thanks for your review! All tables and figures in this article has been checked carefully and some error has been corrected!.
4.Comments: Was the gas inlet a mass-inlet or a velocity inlet? Please give detailed boundary conditions of this model, including the gas inlet, gas outflow. solid inlet and solid outflow.
Response: Thanks for your review! The detailed information of inlet and outflow has been added in Page 7.
“The gas inlet and the solid outflow were set as velocity-inlet, while the gas outflow and solid inlet were set as pressure-outflow.”
5.Comments: Why the different diameters showed few influence on the distribution of CO mole fraction in shaft in Fig 12? Please provide the opinion of author about this phenomenon.
Response:Thanks for your advise. In figure 12, the blast velocity has been set as a constant, which means the penetration depths barely changed with different diameters. So the effeted regions by shaft gas are similar, and the reactions in those region are influenced tinily. And those casue that different diameters showed few influence on the distribution of CO mole fraction in shaft.
6.Comments: What’s the convergence criterion of this model? How to judge weather the model has reached steady state? Please give a detailed introduction in paper.
Response: Thnks for your advise. Detailed introduction has been added in page 7
“When the residual is lower than 10-5. this model could be judged as stable”
7.Comments: Does this research result provide any help or experience for the iron-making process with oxygen blast furnace?
Response: Thnks for your review. Actually, shaft tuyere parameters plays an important role in the oxygen blast furnace process. This paper could provide some reference for the industrial production to choose the suitsble parameters for shaft tuyere.
8.Comments: Besides the temperature and gas conpontents distribution, the production of pig iron, the coke ratio and the coal ratio are important for iron-making process. Did the author consider those indexs?
Response: Thanks for your suggestion once again. All those indexes (including production, coke ratio and other indexes) has been studied in our following studies.
Bset wishes!
Zedong Zhang
Reviewer 2 Report
Please find the attached file with my comments.
Comments for author File: Comments.pdf
In my opinion, the English should be significantly improved. There are a lot of mistakes concerning the use of articles.
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
1.Comments: In the Abstract, there are a lot of results. I prefer more information about the general purpose of the study. Moreover, the novelty should be better highlighted.
Response: Thanks for your review. The general purpose and the novelty of the study has been added in abstract.
“Parameters of shaft tuyere had vital effects on the gas flow distribution and working condition in the TGR-OBF, which determined the production index, CO2 emission reduction and economic benefit. To clarify the effects of shaft tuyere parameters on gas movement behavior and burden reduction in oxygen blast furnace, a 2D steady state model based on with a actual plant conditions in China was published in this study.”
2.Comments: In Table 2, there is a sign “=” in the chemical reactions, but I think the arrow “” is more suitable.
Response: Thanks for your review. It has been corrected.
3.Comments: In section 4.1. Model Verification, there are shown measured values. Could the authors explain how the values were measured?
Response: Thanks for your review. Those values are collected from the blast furnace in our cooperative enterprise.
4.Comments: I think it will be better to combine some figures together, for example, Fig. 25 and Fig. 26, because the number of figures is very high.
Response: Thanks for your review. We have amended those figures in this paper as your advise!
5.Comments: In the Introduction, there is sufficient literature data presented. However, in the Results and Discussion section, the results are not sufficiently discussed with the current literature. It is very important, and without that, the manuscript should not be accepted for publication?
Response: Thanks for your review. Your suggestion is really beneficial. However, the studies on the parameters of shaft tuyere on the oxygen blast furnace are rare, and we are hardly to find some literature to compare and discuss. Actually, we are making some intensive studise on oxygen blast furnace, and we will discuss those research results in our subsequent research!
Bset wishes!
Zedong Zhang
Reviewer 3 Report
The paper titled “Effects of Shaft Tuyere Parameters on Gas Movement Behavior and Burden Reduction in Oxygen Blast Furnace” was systemically investigated the effects of shaft tuyere parameters on gas movement behavior and burden reduction in oxygen blast furnace based on a 2D steady state model of TGR-OBF. It could provide a reliable reference for the production of oxygen blast furnace. However, there are some questions for the author to consider improving the article.
(1) The reaction rate of CO and H2O in table 2 was wrong.
(2) Fig 1 was hazy, please revised it with a more clarity one.
(3) Did the coal ratio in table 3 was used in this model? If not, the author could delete it from boundary conditions.
(4) The unit of shaft tuyere diameter was wrong. According to the context, it should be meter instead of millimeter.
(5) What’s the meaning of the “L” in the parameter “positions of shaft tuyeres” in table 4?
(6) The gradient diagrams in Fig 4, Fig 11 and Fig 18 were wrong.
(7) The change of shaft tuyere parameters will influence the components of top gas, which finally will affect the recycling gas and cause the change of bosh gas components. Has the author considered this problem?
No much comments on the English language.
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
1.Comments: The reaction rate of CO and H2O in table 2 was wrong.
Response: Thnks for your suggestion once again! This has been corrected in table 2.
2.Comments: Fig 1 was hazy, please revised it with a more clarity one.
Response: Thanks for your suggestion. Fig.1 has been instead by a clearer one..
3.Comments: Did the coal ratio in table 3 was used in this model? If not, the author could delete it from boundary conditions.
Response: Thanks for your review. Coal ratio is an important parameters which could influence the components of bosh gas. So we think that it’s nessacery to point it out in this paper.
4.Comments: The unit of shaft tuyere diameter was wrong. According to the context, it should be meter instead of millimeter.
Response: Thanks for your review. This error has been corrected.
5.Comments: What’s the meaning of the “L” in the parameter “positions of shaft tuyeres” in table 4?
Response: Thanks for your review. “L” means the high of the blast furnace shaft..
6.Comments: The gradient diagrams in Fig 4, Fig 11 and Fig 18 were wrong.
Response: Thanks for your review. Those errors has been corrected.
7.Comments: The change of shaft tuyere parameters will influence the components of top gas, which finally will affect the recycling gas and cause the change of bosh gas components. Has the author considered this problem?
Response: Thanks for your review. As the shaft tuyere angles increasing, the standing time of shaft gas in TGR-OBF reduced, which shorten the reaction time of ore and reducing gas.
Best wishes
Zedong Zhang
Reviewer 4 Report
The paper needs substantial language proofreading and correcting. This includes going through the sentences such that they can be understood only the intended way.
Furthermore, when going through the paper, I noticed that for example equations are not explained. Please correct this, especially when the paper deals with simulations and equations.
The paper needs substantial language proofreading and correcting. This includes going through the sentences such that they can be understood only the intended way.
Furthermore, when going through the paper, I noticed that for example equations are not explained. Please correct this, especially when the paper deals with simulations and equations.
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
Comments: The paper needs substantial language proofreading and correcting. This includes going through the sentences such that they can be understood only the intended way.
Furthermore, when going through the paper, I noticed that for example equations are not explained. Please correct this, especially when the paper deals with simulations and equations.
Response: Thanks for your review! We have improved our language and writing techniques to enhance the readability of this paper.And the explanation of those equations are listed in table 6 in Nomenclature.
Bset wishes
Zedong Zhang
Reviewer 5 Report
Although the article is well-written, it does not effectively address the theme of sustainability. Rather, it focuses on investigating a process. While the article is of good quality, it does not significantly contribute to sustainability. The results should be presented more organized, as the current abundance of graphics fails to clearly demonstrate the direct impact of each simulation. Tables or other methods of presenting information more orderly would be preferable. The discussion of results is also lacking, as it does not provide a comparison with other literature studies or offer a thoughtful reflection on them. Consequently, it is recommended that the article be rejected, as it does not effectively address the topic of sustainability, which was the intended focus of the research.
There are no comments on the language.
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
Comments: Although the article is well-written, it does not effectively address the theme of sustainability. Rather, it focuses on investigating a process. While the article is of good quality, it does not significantly contribute to sustainability. The results should be presented more organized, as the current abundance of graphics fails to clearly demonstrate the direct impact of each simulation. Tables or other methods of presenting information more orderly would be preferable. The discussion of results is also lacking, as it does not provide a comparison with other literature studies or offer a thoughtful reflection on them. Consequently, it is recommended that the article be rejected, as it does not effectively address the topic of sustainability, which was the intended focus of the research.
Response: Thanks for your review! Actually, the TGR-OBF is a unique process with low fuel ratio, low CO2 emission and high productivity in the field of ironmaking. It’s a potential progress to reducing CO2 emission of blast furnace, which can improve the achievement of carbon neutrality and improve the sustainable development. The results of our advanced research show that about 30% coke consumable could be cut down in TGR-OBF compared with traditional blast furnace. So we think this study is closely bound up with the issue of sustainability. We have added relevant statement in revised manuscript.
Best wishes
Zedong Zhang
Author Response File: 
Author Response.docx
Reviewer 6 Report
The article studies the effect of tuyere parameters on temperature and gas distribution and reduction degree in a top gas recycling blast furnace. This is done via 2D modeling. Such investigations could contribute towards improvement of industrial practices, especially in terms of reducing CO2 emissions.
The article presents an interesting finding that the position of tuyeres can have considerable impact on the reduction degree of iron oxide. However, the reviewer believes that the current version of article needs major revision, please consider following comments and questions.
1. The authors have not clearly identified a knowledge gap in existing literature.
2. Table 5: what is source of the measured values?
3. Line 67: What is TBF?
4. Line 153, and 394: what do point A and E represent? They are never described.
5. Figure 4, 11, 18 and 25: these figures present CO distribution in shaft, but the scale on figure is indicating temperature contours.
6. Line 184-186: the reported observation is not obvious in Figure 5. Especially that when similar trends are seen in Figure 26, the authors say that those changes were inconspicuous.
7. Line 193: Figure 6 doesn’t represent distribution of CO mole fraction; it shows reduction gas utilization.
8. Figure 7: please explain the effect of tuyere position for when the distance to furnace axis is more than 1.5 m.
9. Line 206 – 207: The reported reduction degrees are for tuyere position, not tuyere diameter.
10. Line 379 should say Fig 29.
11. Section 5: The text presented in this section doesn’t read like conclusions. It is more like a summary of results. Please revise to draw conclusions from the results.
12. The article mostly just presents the results in for of a lot of figures, and lacks discussion of results. It is suggested to have deeper discussions, especially corelating the obtained results to impacts on industrial practices.
13. Can you please comment on the practical issues associated with change in tuyere position?
14. The authors have reported effect of four parameters in four subsections (4.2 through 4.5), where they have presented results in similar formats which makes it look repetitive. Especially, 4.3 and 4.4 present effect of tuyere diameter (at constant volume and velocity), with no difference in results. It seems unnecessary to have so many figures showing the same thing, particularly with no commentary and discussion. It would be better to combine section 4.3 and 4.4.
The review think that they are not highly qualified to assess the quality of English, however, it has been difficult to read and follow this manuscript. Especially, the introduction section which presents the current techniques and issues is written in past tense, which might not have been be a correct choice.
Author Response
Dear Editor and Reviewer
Thanks for your review. They are great helpful for us to perfect our research. And there are our responses for those questions and suggestions.
1.Comments: The authors have not clearly identified a knowledge gap in existing literature.
Response: Thanks for your review! According to existiong literature, there are some studies abuut TGR-OBF had been published. However, the systematic researches about the parameters are lacked. This is the knowledge gap between this study and existing literature.
2.Comments: Table 5: what is source of the measured values?
Response: Thanks for your review. Those values are collected from the blast furnace in our cooperative enterprise.
.
3.Comments: Line 67: What is TBF?
Response: Thanks for your review. “TBF” means “traditional blast furnace”. This has been added in page 4 line 7.
4.Comments: Line 153, and 394: what do point A and E represent? They are never described.
Response: Thanks for your review again! The point A and E signing the highest and the lowest position of shaft tuyere. We used those point in early version of this paper. Now they have been corrected.
5.Comments: Figure 4, 11, 18 and 25: these figures present CO distribution in shaft, but the scale on figure is indicating temperature contours.
Response: We are sorry for our carelessness! We have replaced those picture by correct pictures.
6.Comments: Line 184-186: the reported observation is not obvious in Figure 5. Especially that when similar trends are seen in Figure 26, the authors say that those changes were inconspicuous.
Response: We are sorry for our carelessness! We have displayed a wrong figure of fig.5. We have replaced it with a correcr picture.
7.Comments: Line 193: Figure 6 doesn’t represent distribution of CO mole fraction; it shows reduction gas utilization.
Response: Thanks for your review. This error has been corrected.
8.Comments: Figure 7: please explain the effect of tuyere position for when the distance to furnace axis is more than 1.5 m.
Response: Thanks for your review! Relevant interpretation has been added in the revised manuscript.
“When the distance to furnace axis is more than 1.5 m, the reaction between ore and reduction is controled by bosh gas, And higher shaft tuyere position causes a shorter contact time of ore and reduction gas on the same high, which resultes the incomplete reaction of ore and reduces the reducing degree.”
9.Comments: Line 206 – 207: The reported reduction degrees are for tuyere position, not tuyere diameter.
Response: Thanks for your review. This error has been corrected.
10.Comments: Line 379 should say Fig 29
Response: Thanks for your review. This error has been corrected.
11.Comments: Section 5: The text presented in this section doesn’t read like conclusions. It is more like a summary of results. Please revise to draw conclusions from the results.
Response: Thanks for your review. We have added our conclusions of those results in Section 5.
“Lower position of shaft tuyere is beneficial to extend the contact time of ore and reducing gas, which could improve the reducing degree of ore.”
“According to those results, the change of diameters in a certain control range have small effects on the TGR-OBF”
“The change of tuyere angles showed a slight effects on TGR-OBF”
“In industrial manufacture, the TGR-OBF should be controled lower than 3/10L. Considering the abrasion, the diametere and angle of tuyere should be kept around 130 mm and 0°”
12.Comments: The article mostly just presents the results in for of a lot of figures, and lacks discussion of results. It is suggested to have deeper discussions, especially corelating the obtained results to impacts on industrial practices.
Response: Thanks for your review again! We have added our discussions in Section 4.
“Considering above results comprehensively, a lower position of shaft tuyere is beneficial to the TGR-OBF in industrial production. When the high of tuyere is lower than 3/10L, the reaction time of recycling gas and ore is extended, and more iron oxide could be reduced. It could improve the smelting efficiency and the reducing gas utilization of TGR-OBF, and decreases the coke ratio (insteaded by recycling gas).”
“In the range from 0.088 m to 0.096 m, the change of tuyere diameter showed a slight influence on the TRG-OBF with a constant blast velocity. The penetration depths were almost unchanged , which caused the similar reaction region of reducing gas under different diameters. However, in physical production, smaller diameters will intensify the abrasion between recycling gas and tuyere. Considering above results comprehensively, the diameter of shaft tuyere should be limited around 0.092 mm.”
“In the range from 0.088 m to 0.096 m, the change of tuyere diameter showed a slight influence on the TRG-OBF with a constant blast volume. Although the shortening of shaft tuyere diameter could accelerated the blast velocity, the change was kept in an limited scope by the bound of diameter, which cauesed the slight change on the distribution of reducing gas and temperature. In industrial manufacture, a constant blast volume is more likely to be accepted. Considering the abrasion between recycling gas and tuyere, in the range from 0.088 m to 0.096 m, the diameter is not supposed to be a lower value.”
13.Comments: Can you please comment on the practical issues associated with change in tuyere position?
Response: Thanks for your advise! In practical production progress, the tuyere position is fixed. And the study results could provide a position limlit of tuyere and help the iron plant to confirm the reasonable tuyere position.
14.Comments: The authors have reported effect of four parameters in four subsections (4.2 through 4.5), where they have presented results in similar formats which makes it look repetitive. Especially, 4.3 and 4.4 present effect of tuyere diameter (at constant volume and velocity), with no difference in results. It seems unnecessary to have so many figures showing the same thing, particularly with no commentary and discussion. It would be better to combine section 4.3 and 4.4.
Response: Thanks for your advise again! Actually, the 4.3 and 4.4 have discussed two different issues, although they have similar results. So we think that combining the section 4.3 and 4.4 may cause difficulty in reading. So after our assessment, we keep this merogenesis.
Bset wishes!
Zedong Zhang
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Thank you for your responses to my questions. I recommend this manuscript for publication.
The English of the manuscript is rather ok. There are still some minor mistakes.
Reviewer 5 Report
After thoroughly reviewing your manuscript, it has been verified that several significant corrections and improvements have been made to your work. There are improvements in the text's clarity, coherence, and flow. It is noted that the overall structure of the manuscript logically presents the subject matter of sustainability.
In general, there is an improvement in the quality of your work; the corrections and improvements made have strengthened your manuscript. The dedication and effort in this second round of revision are appreciated.
Improvements can be seen in the style and wording. For example, some ambiguous or unclear phrases have replaced more concise and direct expressions. In addition, grammar, punctuation, and spelling, in general, have been polished, ensuring that your manuscript is linguistically ideal.
Reviewer 6 Report
Thank you for your responses and making the suggested corrections.
Thank you for your responses and making the suggested corrections
