Improvement of the Standard Chimney Electrostatic Precipitator by Dividing the Flue Gas Stream into a Larger Number of Pipes

Round 1

Reviewer 1 Report

Please reduce the size of your introduction.

The quality of figures is very low please improve.

The reference section is very old please improve with new.

Author Response

Reviewer 1:

1. Please reduce the size of your introduction.

• As required, I tried to shorten the introduction and I also supplemented it with more current research

2. The quality of figures is very low please improve.

• Quality of figures and graphs was improowed.

3. The reference section is very old please improve with new.

• I updated the refferences with more current research also

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript compares two constructions of electrostatic precipitators attached to a biomass-fired boiler. The manuscript is original and potentially interested for the readers of this journal, however, the paper cannot be published in the present form and requires significant improvement. I recommend rejection of this manuscript.

 

Specific comments:

1. Introduction. Multi-pipe electrostatic precipitators for flue gas cleaning from small boilers were formerly reported in several papers, which should be mentioned, and the novelty of that presented in this manuscript should be discussed. For example: 1. Part Sci Technol 2010; 2: 547–65. https://doi.org/10.1080/ 02726351003758444; 2. Landtechnik 2010; 65(5): 342–5; 3. Renewable and Sustainable Energy Reviews 137 (2021) 110446, DOI: 10.1016/j.rser.2020.110446; 4. Chem Eng Technol 2017; 40 (No.2) 278–288. https://doi.org/ 10.1002/ceat.201600200.
2. In order to compare the collection efficiency of two different devices a similar inlet dust loading must be used. In this paper the particle mass concentrations differ significantly 1012:342.
3. Line 71: "The polarized particle is repelled by the electrostatic force..." The particle are polarized indeed, but the main mechanism driving the particles to collection electrode is the force acting on charged particle (the particles are charged by ion current in the discharge from the discharge electrode).
4. Line 121: explain why two different power supplies were used in the experiments?
5. Line 136: "The three-filter probe allows to measure all three particle sizes PM10, PM10-2.5, PM <2.5 at once". The main mass of particles emission is concentrated in particles >10 microns. Why the authors ignore this size range?
6. Line 137: "flue gas collection..". Electrostatic precipitator is not used for flue gas collection but for particle separation (collection) from the gas.
7. Section 3. Authors must provide the magnitude of supply voltage during ESP operation, the discharge current (current voltage characteristics), regeneration (rapping) period, inlet temperature, and other important operation parameters.
8. Figure 5. Missing symbol M8 in figure 5. Please also explain the symbols F1, F2, F3 in figure 5.
9. Figure 8. Please also explain the symbols F1, F2, F3 in figure 8.
10. Figures 6 and 7. Is it not a mistake that the total mass of PM<10  microns particles is smaller than those <2.5 microns?
11. What does the symbols MBOx and MSOx mean in figures 6 and 7 ?
12. How the classes of sizes (PM10, PM2.5) were separated from the gravimetric measurements?
13. Line 212: The sentence starting with "The overall separation..." is awkward and must be rephrased.
14. How the plots in figures 9-11 were drawn? Please put the measuring points at this plot (and discuss the measuring procedure) or discrete values when obtained from numerical calculations (please also provide the equations used for these calculations).
15. Line 249: "energy consumption required to maintain the electrostatic field". This statement is absolutely erroneous. The energy is consumed to maintain the gas ionization and ion flow".
16. Line 277: "the resistance of the electrostatic field," there is no such physical variable.
17. Finally, I cannot understand how the collection efficiencies were calculated from the data presented in the manuscript.
18. English needs improvement: For example: change "transformer" to "transformer-rectifier (line 68); "settling electrode." to "collection electrode" (line 72); "which are charging.." to "which are charged by ion current generated by.." (line 73). "chimney draft" to "chimney draught" (line 93); "flow" to "flow rate" (in several places); "concentration of the electrostatic field" to "magnitude of electric field"; "Approaching the electrode spacing... " to "decreasing the interelectrode distance..." (line 276); etc.  

 

Author Response

Reviewer 2:

The manuscript compares two constructions of electrostatic precipitators attached to a biomass-fired boiler. The manuscript is original and potentially interested for the readers of this journal, however, the paper cannot be published in the present form and requires significant improvement. I recommend rejection of this manuscript.

Specific comments:

1. Introduction. Multi-pipe electrostatic precipitators for flue gas cleaning from small boilers were formerly reported in several papers, which should be mentioned, and the novelty of that presented in this manuscript should be discussed. For example: 1. Part Sci Technol 2010; 2: 547–65. https://doi.org/10.1080/ 02726351003758444; 2. Landtechnik 2010; 65(5): 342–5; 3. Renewable and Sustainable Energy Reviews 137 (2021) 110446, DOI: 10.1016/j.rser.2020.110446; 4. Chem Eng Technol 2017; 40 (No.2) 278–288. https://doi.org/ 10.1002/ceat.201600200.

• I incorporated the publications you mentioned in the introduction (line 73) and specified the innovativeness of our solution (line 77).

1. In order to compare the collection efficiency of two different devices a similar inlet dust loading must be used. In this paper the particle mass concentrations differ significantly 1012:342.

• Both types of precipitators were connected to the same combustion equipment and the same chimney with an exhaust fan which kept the chimney draft at approximately the same level of 12 ± 2 Pa. (line 92). In this way, we tried to compensate for the different pressure drop that both precipitators produced.
•  

1. Line 71: "The polarized particle is repelled by the electrostatic force..." The particle are polarized indeed, but the main mechanism driving the particles to collection electrode is the force acting on charged particle (the particles are charged by ion current in the discharge from the discharge electrode).

• Statement "The polarized particle is repelled by the electrostatic force..." has been fixed (line 65)

1. Line 121: explain why two different power supplies were used in the experiments?

• The research used two sources from the same manufacturer and the same principle of operation. The only difference was the lower power range that we could use with a lower cross-section of the pipeline and which significantly reduced the cost of equipment (line 123).

1. Line 136: "The three-filter probe allows to measure all three particle sizes PM10, PM10-2.5, PM <2.5 at once". The main mass of particles emission is concentrated in particles >10 microns. Why the authors ignore this size range?

• Missing mark ''>'' was add to the text.

1. Line 137: "flue gas collection.". Electrostatic precipitator is not used for flue gas collection but for particle separation (collection) from the gas.

• Statement '' flue gas collection '' has been fixed (line 138)

1. Section 3. Authors must provide the magnitude of supply voltage during ESP operation, the discharge current (current voltage characteristics), regeneration (rapping) period, inlet temperature, and other important operation parameters.

• The values of the basic measured quantities were added to section 3 in Table 1. (line 139)

1. Figure 5. Missing symbol M8 in figure 5. Please also explain the symbols F1, F2, F3 in figure 5.

• Filters (Fx) was associated with its size group in the description and symbol M8 was corrected.

1. Figure 8. Please also explain the symbols F1, F2, F3 in figure 8.

• Filters (Fx) was associated with its size group in the description.

1. Figures 6 and 7. Is it not a mistake that the total mass of PM<10  microns particles is smaller than those <2.5 microns?

• Incorrect marking ''> <’’ was corrected in the text

1. What does the symbols MBOx and MSOx mean in figures 6 and 7 ?

• Complicated terms MSOx and MBOx were removed from the text and replaced by the classic numbering of measurements with the mark Mx (measurement, x)

1. How the classes of sizes (PM10, PM2.5) were separated from the gravimetric measurements?

• No only three classes of sizes was separated in cascade cylindrical impactor PM>10, PM10-2.5, PM <2.5.

1. Line 212: The sentence starting with "The overall separation..." is awkward and must be rephrased.

• Statement '' The overall separation'' has been reformulated (line 130)

1. How the plots in figures 9-11 were drawn? Please put the measuring points at this plot (and discuss the measuring procedure) or discrete values when obtained from numerical calculations (please also provide the equations used for these calculations).

• The graphs in section 3 were created using a mathematical model to help us better evaluate the results of the membranes. According to the comment, they have been reworked and supplemented with values.

1. Line 249: "energy consumption required to maintain the electrostatic field". This statement is absolutely erroneous. The energy is consumed to maintain the gas ionization and ion flow".

• Statement '' energy consumption required to maintain the electrostatic field'' has been corrected (Line 262)

1. Line 277: "the resistance of the electrostatic field," there is no such physical variable.

• Statement '' the resistance of the electrostatic field' has been removed from the text.

1. Finally, I cannot understand how the collection efficiencies were calculated from the data presented in the manuscript.

• Efficiencies were calculated from differences in particle mass values captured on the filters using both separator models. Not only the electrostatic effect but also the mechanical effect caused by the change in the shape of the chimney was taken into account in the overall increase in efficiency. (Line 282)

1. English needs improvement: For example: change "transformer" to "transformer-rectifier (line 68); "settling electrode." to "collection electrode" (line 72); "which are charging.." to "which are charged by ion current generated by.." (line 73). "chimney draft" to "chimney draught" (line 93); "flow" to "flow rate" (in several places); "concentration of the electrostatic field" to "magnitude of electric field"; "Approaching the electrode spacing... " to "decreasing the interelectrode distance..." (line 276); etc.  

• English has been modified and several sentences and phrases have been reworded in the text.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper describes a new, optimized construction electrostatic precipitator for particle emissions reduction from small, solid fuel sources and analyses the improvement of its performance. The topic is very interesting in the period of great gas fuel increase, it is appropriate for the journal since it is directly applied.

 

The content lacks some clarity of presentation, and must be improved in some details and some descriptions of the process.

 

The main ambiguity that should be improved is the description of the working parameters measured in the section Results. It should be precisely described what are the parameters for each case in figure 6. and 7. - MBO1-MSO4..I understand that MBO are with the precipitator off, and MSO are with precipitator on, but what is the difference among MBO2 and MBO3?.. are these the combustion phases from figure 1? What does the acronym MBO and MSO stand for? I understand that F1, F2 and F3 from figure 5 are the PM<10, PM10-2.5 and PM<2,5 filters, but it all should be clearly written, perhaps in he figure caption, but also in the text. Where do I read the reduction from 416.03 to 15.83 mg.m-3 (line 209) in the graphical results (fig. 6 and 7.)?? The description of the results should be more clear. A table with the description of the cases MBO1 to MSO4 could maybe help.

 

Details:

The acronym TZL (line 94) is not explained, what does it stand for?

I think the phases of the course of the combustion are not presented in the chronological order in figure 1 and it would be better. The description (lines 96-97) does not coincide with the order in the figure. I suppose it should be 1.loading, 2.burial formation, 3.burning, 4. extiguishing. You better add it to the figure caption too.

Line 109, diameter 300 m, must be mm?

I would like few lines that describe the measuring instrument TCR Tecora Isostack Basic (line 149).

Line 170: C is explained, while it does not appear in the previous formula.

Figure 5. caption, h)?

 

 

I would like a line or formula that explain how is the separation efficiency calculated before the first time when it appears, it would make easier to understand to a wider auditorium.

 

Line 230: The flow remains the same. It is the "flow velocity" that is reduced by the flow area increase..

Author Response

Reviewer 3:

The paper describes a new, optimized construction electrostatic precipitator for particle emissions reduction from small, solid fuel sources and analyses the improvement of its performance. The topic is very interesting in the period of great gas fuel increase, it is appropriate for the journal since it is directly applied.

 The content lacks some clarity of presentation, and must be improved in some details and some descriptions of the process.

The main ambiguity that should be improved is the description of the working parameters measured in the section Results. It should be precisely described what are the parameters for each case in figure 6. and 7. - MBO1-MSO4..I understand that MBO are with the precipitator off, and MSO are with precipitator on, but what is the difference among MBO2 and MBO3?.. are these the combustion phases from figure 1? What does the acronym MBO and MSO stand for? I understand that F1, F2 and F3 from figure 5 are the PM<10, PM10-2.5 and PM<2,5 filters, but it all should be clearly written, perhaps in he figure caption, but also in the text. Where do I read the reduction from 416.03 to 15.83 mg.m-3 (line 209) in the graphical results (fig. 6 and 7.)?? The description of the results should be more clear. A table with the description of the cases MBO1 to MSO4 could maybe help.

• The required information has been added to the results category. Some terms such as (MSO, MBO,) have been removed from the image descriptions and replaced with clearer ones. Size categories were also assigned to the filter descriptions. A mistake of 15.83 mg.m-3 has been fixed (line 227)

Details:

The acronym TZL (line 94) is not explained, what does it stand for?

• The acronym TZL is synonymous with PM and was replaced in the text.

 

I think the phases of the course of the combustion are not presented in the chronological order in figure 1 and it would be better. The description (lines 96-97) does not coincide with the order in the figure. I suppose it should be 1.loading, 2.burial formation, 3.burning, 4. extiguishing. You better add it to the figure caption too.

• Figure 1 has been corrected so that the individual combustion phases follow one another

Line 109, diameter 300 m, must be mm?

• Yes it was corrected.

I would like few lines that describe the measuring instrument TCR Tecora Isostack Basic (line 149).

• Description to measuring device TCR Tecora Isostack Basic was added to text (line 148)

Line 170: C is explained, while it does not appear in the previous formula.

• excess text has been removed from the article.

Figure 5. caption, h)?

• Missing measurement mark M8 was added to the text

I would like a line or formula that explain how is the separation efficiency calculated before the first time when it appears, it would make easier to understand to a wider auditorium.

• The settling efficiency is the percentage expression of the reduction in the average weight of the collected particles compared to the original values before the using of the precipitator.

 

Line 230: The flow remains the same. It is the "flow velocity" that is reduced by the flow area increase..

• It is true informations about changing the flow velocity has been incorporated into the text (line 265) and an unrelated flow chart has been removed from the text.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

All my comments and suggestions have been addressed by the authors and I recommend the paper for publication.