Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures

Round 1

Reviewer 1 Report

This paper studies the accuracy of gas mixture and the test results of two mixing methods. The advantages and disadvantages of the mixing method of gas phase and solid phase materials are explored, and the 20L spherical explosion system is used for experiments. The research content of this paper can provide reference for the explosion characteristics test of gaseous solid mixtures, and also provide technical reference for explosion standards.Based on the above analysis, the synergistic inhibition mechanism on explosion has been revealed. Hence, it is recommended to accept after some revision.

1. The article should put forward in detail the means and methods to prove that the gas and solid mixture can be mixed evenly in 20L sphere.

2. The air conditions for explosion test should be specified, such as temperature, humidity, etc.

3. Why does the conclusion of the article mention " For tests with flammable gas concentrations of more than 40 Mol-% Method I has to be applied."?

Author Response

Dear Reviewer,

thanks for your time and sharing your knowledge on this topic.

Here are the answers to your questions:

1. It can not be proved (or in the moment i don't see a way). This is also the case for only dust explosions and the discussion has been going on for a long time, whether the dust is evenly distributed at the given time-delay-turbulence-combination. We can only say, that if only gases are used the mixing is completed after the given time and we did our best to display the proper A-B-comparison on that topic.
2. You are right, i missed that part and it is definately important. One of our partner institutions used synthetic air and the results varied from ours, so good point, i inserted that (line 153).
3. The 20L-sphere is partially evacuated to 400 mbar before injecting the dust. That is equal to 40% of the atmosphere at the ignition moment. But you are right, Method III could also be used for tests up to 60 %. i added that (line 320).

Kind regards

Stefan H. Spitzer

Reviewer 2 Report

The authors present an experimental investigation on hybrid mixtures, solving some practical issues involving the use of standard methods developed for non-hybrid mixtures.

The article is well written an clearly describe the background as well as the aim and methodology applied. Conclusions are supported by presented results.

Author Response

Dear Reviewer,

thanks for your time and sharing your opinion.

I hope you enjoyed reading and that you will benefit from the upcoming standard on hybrid dust-gas mixtures.

Kind regards

Stefan H. Spitzer