Aging aerosol in a well-mixed continuous-flow tank reactor: an introduction of the activation time distribution

Friebel, Franz; Mensah, Amewu A.

doi:https://doi.org/10.5194/amt-12-2647-2019

Articles | Volume 12, issue 5

https://doi.org/10.5194/amt-12-2647-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-12-2647-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 5

Research article

|

08 May 2019

Research article |

| 08 May 2019

Aging aerosol in a well-mixed continuous-flow tank reactor: an introduction of the activation time distribution

Franz Friebel and Amewu A. Mensah

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Final revised paper (published on 08 May 2019)
Supplement to the final revised paper
Preprint (discussion started on 12 Nov 2018)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Referee Comments.', Anonymous Referee #1, 09 Dec 2018
- AC1: 'answer to reviewer 1', Franz Friebel, 22 Feb 2019
RC2: 'scientific comments', Anonymous Referee #2, 21 Dec 2018
- AC2: 'answer to reviewer 2', Franz Friebel, 22 Feb 2019
- AC3: 'answer to reviewer 2_corr', Franz Friebel, 25 Feb 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Franz Friebel on behalf of the Authors (22 Feb 2019) Manuscript

ED: Referee Nomination & Report Request started (25 Feb 2019) by Charles Brock

RR by Anonymous Referee #1 (12 Mar 2019)

Suggestions for revision or reasons for rejection

Overall the manuscript has a few technical and stylistics quirks that are arguable (and some less so, e.g., P1 L17 “…(OFR)…” should be plural) yet I do not feel fit to criticize or amend, and leave to the discretion of the Editor. I thank the authors for educating me on the difference between an aerosol and an aerosol particle, as well as taking my previous suggestions into consideration.

P1 L10: I will insist here as I did throughout my first review. I recommend changing “…aerosol chamber as a Continuous flow Stirred Tank Reactor (CSTR).” To “…aerosol chamber in continuous fashion, aiming to mimic the characteristics of a Continuous flow Stirred Tank Reactor (CSTR).” The authors are free to choose what they see fit, as this is a small detail, but I will put my view forth once more. Same applies for: P2 L4-5.

P2 L6-7: Unless I’m mistaken, the authors don’t mean what they’re saying when referring to Simonen et al.’s TSAR. When I read “This greatly exceeds the typical aging times of several minutes that can be reach within Oxidation Flow Reactors (OFRs; (Simonen et al., 2017)…” I automatically think the TSAR only ages compounds for a couple of minutes, but that’s not the case. It just has a low residence time. May I ask the authors to rephrase, likely (if I understand correctly) from a point of view of V/Q?

P2 L13: consider a hyphen e.g. “CSTR-approach”, as used in P2 L41.

P2 L14: Again, I insist that phrasing like “The volume of the CSTR is actively stirred…” be changed. May I offer, for example, “The vessel is actively stirred…”.

P3 L5: “ORF”

P3 L7: Please cite Kang et al. after the PAM and George et al. after the TPOT.

P3 L16: From a technical perspective, a flow tube reactor is not a PFR. Unless I’m mistaken, it’s a term arising from atmospheric chemists. I’d ask the authors to remove “…or flow tube reactor…”.

P3 L27: Citations for PAM and TPOT are reversed.

P3 L33: To the authors’ choice, they can consider changing “volume” to “vessel”.

P3 L34-37: Yes! I thank the authors for taking my previous suggestions on v1 of the manuscript into consideration.

P6 in general: Thank you again to the authors for having a much clearer description of what ‘non-gradual transitions’ and ‘external parameters’ are. I think now the readers, by enlarge, should be able to understand this at first pass.

P15 L20: Didn’t the authors already introduce the SAPHIR earlier? I think they could just mention it so the reader is more aware they have prior knowledge of the SAPHIR and its modes of operation (continuous vs. batch).

P15 L20-24: What was the flowrate? Depending on that the reader can estimate V/Q in the tubing and then decide if it really is negligible.

P16 L17: Visa versa?

P18 L9: I have never head of the puls-function. Perhaps pulse-function? But even then, I strongly believe in the technical difference between a pulse (finite peak height) vs. the PFR E-Curve (infinite peak height), so I would argue “often referred to as puls-function” be removed. In the same vein, it’s not “due to technical restrictions” that any reactor (OFR or otherwise) is not on either end of the CSTR to PFR spectrum, it’s simply reality. I appreciate these are small details but I think they’re important.

P20 L21: agree in ‘some’ parameters and disagree in ‘other’ parameters? This sentence, though, is a very good highlight of the work the authors have done and why it is important.

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ED: Publish subject to technical corrections (13 Mar 2019) by Charles Brock

AR by Franz Friebel on behalf of the Authors (17 Mar 2019) Author's response Manuscript

Short summary

Simulating atmospheric aging processes in the laboratory under atmospheric conditions is a challenging task. The main obstacle is achieving long observation times with a reasonable amount of technical and financial input. We adapted the concept of the continuous-flow stirred tank reactor in order to achieve long observation times (up to 16 h) in small chamber volumes (3m3). We successfully tested this concept by oxidation of soot particles with ozone.