Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed

Round 1

Reviewer 1 Report

The authors present a study on particle movement in a circulating fluidised bed for the special case of desulpherised ash. The research is clearly motivated and sufficiently placed within the open literature. Experimental equipment and approach are clearly described; experiments are well chosen, even if the authors do not apply some method of experimental design which would increase the siginificance of their data and also ease the presentation and interpretation.

Throughout the manuscript, language needs to be improved, for example capitalisation of names (e.g. "Geldart").

Fig. 7 is hard to read and needs improvement.

What is the shape of the ash particles? Classification in Geldart A or C is performed using the sphere equivalent ... so, how spherical are the particles?

What is the solids loading of the CFB? Is it still a dilute flow or a dense fluid-solids flow?

Section 4 needs to be integrated with section 3.

Interpretation of data is mostly descriptive. Authors need to improve the discussion, i.e. give some reasoning about the "why" the results are as observed and how the observation compare to similar observations in the literature (and the interpretation therein).

A new section "Summary and conclusion" (or similar) should be added to the end of the manuscript.

Author Response

Thank you very much for providing us the opportunity to resubmit our manuscript (Manuscript number: processes-1281171). We have seriously considered and point-by-point addressed the reviewers’ remarks, and revised the manuscript accordingly.  All changes in details are attachted in the Word file. Please see the attachment. 

Author Response File: Author Response.docx

Reviewer 2 Report

Figure 1, 3, 5, 7 should be enlarged and more clear

Author Response

Thank you very much for providing us the opportunity to resubmit our manuscript (Manuscript number: processes-1281171). We have seriously considered and point-by-point addressed the reviewers’ remarks, and revised the manuscript accordingly.  All changes in details are attachted in the Word file. Please see the attachment. 

Reviewer 3 Report

This paper investigated the flow characteristics of the desulfurized ash particles in the fluidized bed, to find the axial and radial distribution of the solids holdup of the desulfurized ash particles. This article could be considered in the next round. The current manuscript is not in a satisfactory level. So I recommend a major revision. In the next round, the authors should address the following points.

1. The first question is how representative a cold model experiment could be. Is it able to represent the real scenario? In real operating condition, the high temperature could significantly change the pressure, space velocity, viscosity, and drag force.

2. The term “type A particles” should be avoided in abstract.

3. Please rephrase the sentence “In the radial distribution, the central area is lower, the sidewall area tends to be higher.”

4. “the mass concentration of SO2 emissions is not higher than 35 mg/m”, revise to “should not be”

5. “and the total amount of particles stored is the highest It can reach 400 kg” structural problem in this sentence.

6. The geometrical information like height, width should be marked in Fig. 1.

7. “After testing and calculation, the angle of repose of the desulfurized ash particles is 52.6°, while the angle of repose of the FCC type A particles is 32°. The comparison shows that the flow properties of the desulfurized ash particles are very poor.” This part needs a photo to facilitate the understanding.

8. “According to the geldart particle classification, the desulfurization ash The ash particles belong to geldart C type particles.”

9. It is necessary to provide a clear definition of holdup. I assume it is the volume fraction of solid. If necessary, mathematical definition should be there.

10. In figure 7, why do not the authors show a two dimensional profile with axial coordinate and radial coordinate? This type of profile would perfectly match Figure 1 (axial coordinate-vertical axis, radial coordinate-horizontal axis).

11. Figure 8 and 7 are showing the same results, just in different forms. This is not necessary.

Author Response

Thank you very much for providing us the opportunity to resubmit our manuscript (Manuscript number: processes-1281171). We have seriously considered and point-by-point addressed the reviewers’ remarks, and revised the manuscript accordingly.  All changes in details are attachted in the Word file. Please see the attachment. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have thoroughly improved the manuscript. The reviewer recommends acceptance.

Author Response

Thank you very much for providing us the opportunity to resubmit our manuscript (Manuscript number: processes-1281171). We have seriously considered and point-by-point addressed the reviewers’ remarks, and revised the manuscript accordingly.  Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

This paper investigated the flow characteristics of the desulfurized ash particles in the fluidized bed, to find the axial and radial distribution of the solids holdup of the desulfurized ash particles. This article could be considered in the next round. The current manuscript is not in a satisfactory level. So I recommend a major revision. In the next round, the authors should address the following points.

1. The first question is how representative a cold model experiment could be. Is it able to represent the real scenario? In real operating condition, the high temperature could significantly change the pressure, space velocity, viscosity, and drag force.

2. The term “type A particles” should be avoided in abstract.

3. Please rephrase the sentence “In the radial distribution, the central area is lower, the sidewall area tends to be higher.”

4. “the mass concentration of SO2 emissions is not higher than 35 mg/m”, revise to “should not be”

5. “and the total amount of particles stored is the highest It can reach 400 kg” structural problem in this sentence.

6. The geometrical information like height, width should be marked in Fig. 1.

7. “After testing and calculation, the angle of repose of the desulfurized ash particles is 52.6°, while the angle of repose of the FCC type A particles is 32°. The comparison shows that the flow properties of the desulfurized ash particles are very poor.” This part needs a photo to facilitate the understanding.

8. “According to the geldart particle classification, the desulfurization ash The ash particles belong to geldart C type particles.”

9. It is necessary to provide a clear definition of holdup. I assume it is the volume fraction of solid. If necessary, mathematical definition should be there.

10. In figure 7, why do not the authors show a two dimensional profile with axial coordinate and radial coordinate? This type of profile would perfectly match Figure 1 (axial coordinate-vertical axis, radial coordinate-horizontal axis).

11. Figure 8 and 7 are showing the same results, just in different forms. This is not necessary.

Author Response

Thank you very much for providing us the opportunity to resubmit our manuscript (Manuscript number: processes-1281171). We have seriously considered and point-by-point addressed the reviewers’ remarks, and revised the manuscript accordingly.  Please see the attachment. 

Author Response File: Author Response.pdf