Round 1

Reviewer 1 Report

I think scientifically this article is inadequate, the authors tested the cyclone separator in the field of CEMS, but this is not innovative. The structure of the cyclone separator is not new and this is not the first time it has been reported. In addition, the problem solved by the authors is not outstanding and I do not see any problem being solved. There are only a few simple efficiency graphs throughout the text, and there is no discussion of the scientific issues being addressed. Therefore, I think this work needs to be enhanced to explore scientific issues if it is to be published. For example, what are the current problems with the measurements, why they cannot be easily solved, and what contributions the authors have made and the science behind this.

Author Response

Thanks for your comments. We have already revised our MS based on your comments. Please see the attached file. 

Author Response File: Author Response.docx

Reviewer 2 Report

Manuscript Number: atmosphere-1865150

Title: The effect of a hybrid pretreatment device for CEMS on the simultaneous removal of PM2.5 and water vapor

Authors: Choi et al.,

 

Comments

The work presented a hybrid cyclone module combining a traditional cyclone and a rapid cooling module to remove water vapor, and particulate matter (PM). However, many scientific points are clear that should be significantly improved.

1.       It is difficult to understand why selecting the inlet flue gas temperature of 180°C; the absolute humidity of 150 g/m³ ; and PM_2.5 concentration of 1 mg/m³. It is high humidity and low PM concentration condition. What kinds of industries are the targets of their application?

2.       Moisture content in flue gas could affect the value of OPC (Optical Particle Counters). The particulate matter could be aggregation and affect the particle size in flue gas. The authors should mention the issue.

3.       It is necessary to explain the moisture removal mechanisms in this study. Based on Figure 5, the moisture removal efficiency was in the range of 60-80% and depends on the moisture content of inlet flow.

4.       The work was only 6 slpm and the authors seem to have done their work on a lab scale. It is a limitation to scale up their system and apply it to the processes of industry.

5.       Low SO₂ loss is reasonable that is due to the low solubility of SO₂ in water.

Author Response

Thanks for your comments. We have already revised our MS based on your comments. Please see the attached file. 

P.S. Editor will send revised MS to you

Author Response File: Author Response.docx

Reviewer 3 Report

Comments

The authors developed the hybrid cyclone, a pretreatment device of CEMS, to increase the removal rate of water and PM and reduce the loss rate of targeted water-soluble gases. This study has implications for improving both the accuracy of monitoring results and the longevity of equipment. However, there are still some problems to be worked out, so a major revision may be required. My comments are as follows.

 

(1) Figure 1, some details are missing. If possible, please complete the process of air flow through condensation to remove water and PM.

(2) Section 2.2, in which step was the sampling of PM carried out? In addition, a configured cascade impactor composed of four stages was used in this study, but only PM2.5 was mentioned in this paper. The influence of particle size in this study was not mentioned.

(3) Section 2.3, why was SO2 only selected as the standard gas in this study? Do other water-soluble gases also conform to the conclusion?

(4) Section 2.4.1, if possible, mark the conical part of the cyclone in Figure 1.

(5) Lines 176-177, “The mixture of particulate matter and water exhibiting nucleation.” Is this sentence incorrect? Please check the grammar and spelling throughout.

(6) Figure 4, the PM2.5 removal rate under dry conditions was missing.

(7) Lines 260-261, please supplement the p value for the significance level of the correlation.

(8) Lines 293-295, whether the statement was appropriate? The SO2 loss rate of a Nafion dryer at <20 g/m3 of absolute humidity (50 % relative humidity) was 2.7 %, which was lower than that of the hybrid cyclone.

(9) Please unify the format of figures.

(10) References can be unified according to the requirements of the journal.

Author Response

Thanks for your comments. We have already revised our MS based on your comments. Please see the attached file. 

P.S. Editor will send revised MS to you

Author Response File: Author Response.docx

Reviewer 4 Report

The paper “The effect of a hybrid pretreatment device for CEMS on the simultaneous removal of PM2.5 and water vapor” deals with an interesting and timely subject.

The manuscript aims at the simultaneous removal of water vapor and particles by operating a hybrid cyclone as a pretreatment device for continuous emission monitoring systems.

I have the following comments:

• The topic is original and relevant in the field, addresses a specific gap in the field and provides a novel pretreatment approach in designing continuous emission monitoring systems. The references section seems appropriate, the conclusions section is consistent with the evidence and arguments, and it addresses the main question posed.

I suggest the authors emphasize the novelty of the manuscript in the introduction section.

• Moreover, the idea of the hybrid cyclone application and experimental procedure should be explained and discussed in detail in the manuscript.

• Figures should have the same format and style throughout the entire manuscript.

• Acronyms should be explained when first used.

• Add the nomenclature section

I suggest accepting the paper if the authors adequately address these comments.

Author Response

Thanks for your comments. We have already revised our MS based on your comments. Please see the attached file. 

P.S. Editor will send revised MS to you.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The solubility of SO2 is not low into water, please check it. for example, the article,

Solubility of SO2 in Water from 263.15 to 393.15 K and from 10 to 300 bar: Quantitative Raman Spectroscopic Measurements and PC-SAFT Prediction

In addition, please check the humidity effect on OPC and prove it.

Author Response

Thank you for your comments. Our authors tried to improve the scientific points you addressed.

Author Response File: Author Response.docx

Reviewer 3 Report

no

Author Response

Thank you for your comments. Our authors tried to improve English language and style points you addressed.