PONE-D-21-08473

Yields and characterization of bio-oils from fast pyrolysis of tobacco processing wastes in an ablative reactor under vacuum

PLOS ONE

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PLOS ONE

Additional Editor Comments:

Your MS Needs major revisions based on reviewers' comments. In addition, I have also gone through the MS and found that your MS must be read by a native language editor in order to improve the language of the MS. Also please improve the discussion proving recent references. 

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2. Please provide further details on the source of the tobacco residues, such that similar samples could be obtained by another researcher seeking to reproduce your work.

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Reviewers' comments:

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

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Reviewer #1: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Manuscript review

Manuscript number: PONE-D-21-08473

Manuscript title: Yields and characterization of bio-oils from fast pyrolysis of tobacco processing wastes in an ablative reactor under vacuum

Summary:

Vacuum pyrolysis of tobacco residues was performed at various temperatures (400-600 degC) and ablative blade rotation speeds. Product analysis is reported with surprising quantities of alkanes.

General comments:

The paper has many standard experimental analyses seen in pyrolysis literature and there are some surprising results showing alkanes- though without a mass balance it is not clear how much. The biggest weaknesses of the paper are the following:

1) There is no clear hypothesis.

2) Relevant literature is not cited – notably, there are many papers out there regarding vacuum pyrolysis. Further, have other researchers found alkanes to be present in tobacco pyrolysis oils? The manuscript does not discuss if this is a new finding or not.

Location Comment

Introduction The premise of the paper is vacuum pyrolysis, which is a very specialized technology. However you did not cite a vast body of research which has explored how vacuum pyrolysis changes the product spectrum. Please add a paragraph explaining this choice.

Introduction What is the scientific question and hypothesis? Stating a list of experiments is not a very good story, so to speak.

Experimental procedure Please provide a figure illustrating your unique reactor configuration.

Experimental procedure It is so good that you ran the experiments 3x. Nice job.

Results Please compare your results to at least some of the many, many vacuum pyrolysis papers available in the literature. E.g. Garcia-Perez et al. 2002.

Table 1 Please report the ash content and proximate analysis of the char produced from this work. I am very curious what char looks like from this feedstock under vacuum pyrolysis.

3.3.1 NMR analysis Where are your spectra? Tables 2 and 3 should be connected to a figure with overlayed data.

Table 4 Area percentage is a good start. Do you have an idea of mass balance from this reactor? GCxGC only captures monomer and dimer compounds, but it is well known that vacuum pyrolysis produces a large amount of lignin and sugar derived oligomers, as seen in the literature.

Fig. 4 This reaction scheme does not seem likely. Hydrogenation needs either a metal-acid catalyst or very high temperatures. All of the hydrocarbons come from xylose?

General What is the maximum temperature of the hot points in the reactor?

Reviewer #2: Authors have performed vacuum ablative pyrolysis of tobacco residues to generate bio-oils and characterized it through three-dimensional gas chromatography/time-of-flight mass spectrometric analysis and NMR. The idea and experimental plan seem interesting, but manuscript required some corrections as given below pointwise:

In title, please change “yields” as “production”.

In abstract section, please include 1-2 line of background and 1-2 line of conclusion.

At page no. 1, kindly provide reference for the statement (In the north……….via pyrolysis) given in line 27-30.

At page no. 4, in line no. 108, instrument name “Bruker 400 UltraShield” is incomplete, correct is as “Bruker 400 UltraShield NMR”.

In tables, none of the table shows any statistical analysis. Kindly, include statics.

At page no. 6, in line line no. 153-154, i. e. “At the highest temperature (600 ºC)…..54.4% w/w yield at the highest speed”. These results have not been compared with the existing literature. Kindly, compare and discuss your results.

Kindly, include the desired characteristics of efficient bio-oil somewhere in the manuscript.

The compositional analysis of tobacco residues for cellulose and hemicellulose should be included in the manuscript.

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Reviewer #1: No

Reviewer #2: Yes: Dr. AJAY KUMAR PANDEY

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Attachment

Submitted filename: Manuscript review PONE-D-21-08473.docx

Production and characterization of bio-oils from fast pyrolysis of tobacco processing wastes in an ablative reactor under vacuum

PONE-D-21-08473R1

Dear Dr. Tippayawong,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Abhay K. Pandey

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

The authors addressed reviewer comments

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: Authors have addresses all the queries in impressive way, therefore I recommend to accept this manuscript for publication.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No