Performance Identification of a Steam Boiler Burner via Acoustic Analysis

Round 1

Reviewer 1 Report

This work utilized acoustic data to study the performance and to identify the optimum operating points of natural gas burners that are used in steam boilers. The results show that operating parameters and acoustic analysis results can be correlated and confirmed with the emission measurement results. The study is interesting, while some revisions are needed:

1. The introduction is poorly written. The literature review should be reorganized. It is strongly recommended to separate the introduction into several paragraphs for better flow.
2. There should be one paragraph at the end of the introduction which provides clear and concise summary for the methods, results and significance for this work.
3. The first paragraph in Results section “Measurements were taken…” should be moved to Materials and Methods section.
4. For Figure 5, the legend should be in numerical order. The lines should use both different types (e.g., solid, dots…) and colors in order to better distinguish them.
5. The discussion is weak and should be refined. For example, “It was concluded that the Yule–Walker 160 method is more suitable for these data characteristics”, how is this concluded? Please explain more. Also, provide more discussion for the power spectral density values in terms of different excess air coefficients.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The study examined the operating parameters of the natural gas boiler’s burner along with acoustic data. The paper is interesting and in line with the aims and scope of this journal. The impression is that the results from the Figures are very sparsely described. The discussion of the results should be expanded with the appropriate text for better explanations. Also, the following comments need to be addressed:

1)        The main objectives of the study have to be clearly defined at the end of the Introduction.

2)        The authors need to better emphasize a novelty of the paper - what is new compared to the existing publications in the literature?

3)        Line 91. “These results are presented as Yule–Walker equations.“ - Did you mean on Equation 6? The equation 6 needs to be mentioned in the main text above equation 6.

4)        Nomenclature should be added.

5)        The subject boiler and operation parameters has to be explained in more detail (location, power, dimensions, mass flows of natural gas and air…).

6)        Fig. 2. Why the normalized amplitude are monitored only for 10 s? Is it enough time for reliable conclusions? Explain.

7)        Lines 135-137. “The excess air coefficient of 1.14 of the boiler measured at the third measurement was determined as the excess air coefficient where combustion is the most suitable as per the criteria set by standards regarding flue gas emissions and efficiency values.“ – Based on which criteria? Where are these standards for flue gas emissions and efficiency values? This analysis needs to be in the details/better explained.

8)        Note that Table 2 is not mentioned in the main text in the Section 3!

9)        Improve the legend in Fig. 5 to be more clear for readers.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

 1.     Here, fluctuations depending on the combustion state are reflected in the graphics. Subsequently, these values were transferred from time domain to frequency domain for each excess air coefficient.

It is better to analyze the influence of these including volume of burner, the O2%, and the fuel%?

2.     While recording acoustic data, changes were made in the λ excess air coefficient values and flue gas emissions and boiler efficiency values were simultaneously measured for each excess air coefficient value.  

How to determine the value of λ ? as the 1.07 1.11 1.14 1.16 1.17 1.19 1.30 1.35?

3.     The “Discussion” is too short without references, what is the difference of your research?

4.     It needs to add new references in the last three years, as least 5~8.

5.      The sentences need to be polished.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have properly addressed the reviewer's comments. It can be published in Processes.

Reviewer 2 Report

The authors improved their paper in an acceptable form for publication.

Reviewer 3 Report

The revision is good