Fundamental Study on Ammonia Low-NOx Combustion Using Two-Stage Combustion by Parallel Air Jets

Round 1

Reviewer 1 Report

This is a kind of well-thought-out experiment as well as a well-prepared manuscript.

 

Remarks:

Section 2: The material of the furnace should be given.

Section 2: Is there any gas mixer before the burner?

Line 144: "As lambda_1 decreased ..." (not increased).

Lines 227-238: Providing appropriate chemical reactions should be considered within this paragraph.

 

I recommend publishing this paper after very minor revision.

Author Response

I am grateful for your review of our paper.

We have answered each of your points in the attachment.

We hope the revised version is now suitable for publication and look forward to hearing from you in due course.

Sincerely,

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript Fundamental study on ammonia Low-NOx combustion using two-stage combustion by parallel air jets by K. Kikuchi et al. is a detailed experimental study of the effects of adding secondary air flow into the combustion furnace on NOx formation/reduction. The authors varied several parameters (or their ratios) affecting the overall combustion, such as diameter of the main burner, diameter of the secondary air nozzles, distance of the secondary air nozzles with respect to the burner, excess air ratio and ammonia mixing ratio. The results clearly show that adding secondary air can have plausible effect on NOx concentration, even though there are opposing tendencies leading to conditions when the NOx is reduced most effectively. The manuscript presents a careful study which shows that the two-stage process is effective and acceptable emission levels of NOx satisfying air pollution limits can be obtained even when pure ammonia is burned. The work is quite interesting both per se and for the readership of Processes and I recommend it for publication. Below I have a few remarks that the authors should consider for an improved readability of the presented work:

1) The definition of the air excess ratios Lambda_tot and Lambda_1 should be defined precisely at their introduction, otherwise the reader may be left in doubt of their meaning.

2) Likewise, the definition of the mixing ratio E_NH3 should be specified precisely.

3) lines 269-270: The sentence “However…   …NOx reduction rate for single-stage combustion significantly depended on the ratio of primary air flow rate to secondary air flow rate,… “  is confusing, because single-stage combustion does not have any secondary air flow.

Author Response

I am grateful for your review of our paper.

We have answered each of your points in the attachment.

We hope the revised version is now suitable for publication and look forward to hearing from you in due course.

Sincerely,

Author Response File: Author Response.pdf