Characteristics of Pyrolysis and Low Oxygen Combustion of Long Flame Coal and Reburning of Residues

Round 1

Reviewer 1 Report

The following corrections should be done before further processing;

1- Abstract section should be rewritten more scientifically by presenting results in more detail. Moreover, it is too long

2- The following references are recommended to cite in section 1

• The peculiar influence of the mineral impurities content in coal-water fuel on the regularities of fuel drop ignition and combustion
• Thermodynamic effects of cycling carbon dioxide injectivity in shale reservoirs
• Effect of oxidation temperature and oxygen concentration on macro characteristics of pre-oxidised coal spontaneous combustion process
• Experimental investigation and mathematical modeling of gas diffusivity by carbon dioxide and methane kinetic adsorption
• The feasibility analysis of underground gas storage during an integration of improved condensate recovery processes
• Modeling of CO2 capture ability of [Bmim][BF4] ionic liquid using connectionist smart paradigms

3- Literature review is really poor and should be compared to the novelty of your work one by one. For example, say ...et al... did this and we present this. why is different and what are the novelties. It is not acceptable to say just the novel points without any comparison.

 

4- Section 2.2, add a picture to be more sensible for readers

5- Section 2.1, could you please explain the number of coal samples that you are used? What are the properties?

 

6- The nomenclature section should be added to define each parameter and its units?

 

7- In Figure 1, what would happen for higher temperatures?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The article is well written and has the correct structure. The great advantage of the article is interesting laboratory tests and their extensive analysis. Here are some minor reamrks:

1. Line 86, please check the entry "... ..under a lean oxygen gradient of 21-0% to compare ...".
2. Line 109, China in capital letter.
3. In line 116, please write what type of furnace was used in the research.
4. Lines 131,134,412, separate the unit from the digit.
5. Line 135, please write down why the temperatures were selected: 350, 400, 450 and 500.
6. Line 184, regarding the unit volatile components weight Wv-%, remove the minus sign; the same for residual value Wc-% and oxygen combustion Wp-% and lines 205-208, 243,343,362.
7. Figures 2,3,4, vertical axis - please correct the notation, use the same notation as in the other figures, for example ().
8. Line 310, please write two or three sentences from which it follows, that "... .pyrolysis residues experienced different constant temperature conditions in the early stage ..."

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Reviewer Comments

 

 

The present manuscript describes an experimental study of pyrolysis and low oxygen combustion of long flame coal and reburning of residues. A manuscript has a practical application. The results show that the increasing of constant temperatures can promote both pyrolysis and low oxygen combustion, while the pyrolysis reaction accelerates the combustion process of residues and the low oxygen combustion hinders reburning.

The paper is well structured and can be accepted for publication after providing several corrections mentioned below.

 

In the Introduction section, an enhanced literature review is required. For this study, the authors have used only 36 literature sources. It seems insufficient for such type of research. It will be great if the authors show some description in context – Why it is important to conduct this study? Can it be used for the underground or surface gasification process?

 

Line 107. 2.1 coal samples – Capital letter “C”

Lines 41-42. Long flame coal belongs to bituminous coal with high volatile matter and low rank. What is the range value of volatile matter?

Line 55-58. Regarding “spontaneous combustion” please look at the study and consider it in your work: Gamiy, Yu., Kostenko, V., Zavialova, O., Kostenko, T., & Zhurbynskyi, D. (2020). Identifying sources of coal spontaneous heating in mine workings using aerogas control automatic systems. Mining of Mineral Deposits, 14(1), 120-127. https://doi.org/10.33271/mining14.01.120

Line 135. What are the boundary conditions for heating rate? Why only 350°C, 400 °C, 450 °C and 500°C at the heating rate of 10 °C /min were studied? Why not 550°C or 300°C with heating rate of 20 °C /min?

Line 178. As for me, it will be easier to see the difference between curves if all curves will be placed in one figure. Please consider combining figure 1a-d into one.

Figures 2,3,5,6,7,8,10 can be combined too.

 

In general, I must admit that a very good study was performed.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

I am more than satisfied with the corrections provided by the authors.
This study is an important contribution to the field of pyrolysis and combustion of coal.