Life Cycle Assessment of the High Performance Discontinuous Fibre (HiPerDiF) Technology and Its Operation in Various Countries

Round 1

Reviewer 1 Report

The manuscript is related to life cycle assessment (LCA) of HiPerDiF technique as a method of fiber reclamation with focusing on environmental impacts. Four measures are considered including HH, EQ, CC, and Re. The following points should be considered:

1. The system explained to use for reclamation of fibers is a laboratory-scale machine. But, in large scale process some factors will add to process or change, certainly. For example the mixing is not carry out with magnetic stirrer and energy consumption is different in a mixing vessel. It has mentioned that the process is in trl2 and the results are valid in commersial scale. The authors should state that how the results could be applied in that conditions.
2. Which portion of CFRPs are used in the targeted countries? Is it an important factor to be considered or not?
3. It could be helpful to state abbreviations in a table.
4. As authors stated the economic issues are not included in this study. But, it is a determining parameter for example in transportation of recycled materials. It could be helpful if the authors point how the economical aspects could coupled with the results of this manuscrip.

Author Response

Dear Reviewers, 

Thank you for taking the time to review this manuscript.

I had some formatting issues with the previous version of the manuscript which I have rectified with this latest version. 

Apologies for the confusion and I look forward to receiving your feedback.

Yours sincerely, 

Amy Fitzgerald

 

Reviewer 1

The manuscript is related to life cycle assessment (LCA) of HiPerDiF technique as a method of fiber reclamation with focusing on environmental impacts. Four measures are considered including HH, EQ, CC, and Re. The following points should be considered:

1. The system explained to use for reclamation of fibers is a laboratory-scale machine. But, in large scale process some factors will add to process or change, certainly. For example the mixing is not carry out with magnetic stirrer and energy consumption is different in a mixing vessel. It has mentioned that the process is in trl2 and the results are valid in commersial scale. The authors should state that how the results could be applied in that conditions.

Thank you for this comment. We are in agreement and concur that the entire process would be optimised for scale up and that some of the original appliances used would be redundant. However, we have sought out the best advice possible with the scaling methodology. While this is not an exact science, based on what we know we have assumed the scale up to be linear, with a certain margin of error, so that we can effectively realise a working model for the machine scenario. See lines 514 – 526 in the document.

1. Which portion of CFRPs are used in the targeted countries? Is it an important factor to be considered or not? While this is an important comment, it falls outside the scope of the LCA’s system boundary. However, in the section “Interpretation and future considerations” (starting on line 667) we highlight that an expansion of the system boundary would be important in future studies – this research intends to provide an indicative result that decision makers can use to plan.
2. It could be helpful to state abbreviations in a table. Added after the acknowledgements.
3. As authors stated the economic issues are not included in this study. But, it is a determining parameter for example in transportation of recycled materials. It could be helpful if the authors point how the economical aspects could coupled with the results of this manuscrip. At line 720, a sentence has been added to include this reviewer’s point.

Reviewer 2 Report

This paper provides an overview of the problems of high performance discontinuous fibre technology. Carbon fibre reinforced  polymer composite have become increasingly popular in several area of the application.

One of the aims of developing new materials is to obtain better mechanical properes which ensure higher durability of the mechanical systems where they are used.

In this paper discusses environmental issues that arise during production carbon fibre reinforced  polymer composite:

 

In this paper suggests a new method for obtaining the  polymer composite.    I think this paper will be interesting for readers of this journal.

I am recommending to include in the references the next publications

1.S.P. Repetsky, I. G. Vyshyvana,Y.Nakazawa,S. P. Kruchinin, S.Bellucci., Electron transport in carbon nanotubes with adsorbed chromium impurities.Materials (2019), 12, 524.

2.J.Bonca and S.Kruchinin (Eds). Nanostructured materials for the detection of CBRN. Springer, 2018, P.350 .

Author Response

Reviewer 2

This paper provides an overview of the problems of high performance discontinuous fibre technology. Carbon fibre reinforced  polymer composite have become increasingly popular in several area of the application.

One of the aims of developing new materials is to obtain better mechanical properes which ensure higher durability of the mechanical systems where they are used.

In this paper discusses environmental issues that arise during production carbon fibre reinforced  polymer composite:

 

In this paper suggests a new method for obtaining the  polymer composite.    I think this paper will be interesting for readers of this journal.

I am recommending to include in the references the next publications

1.S.P. Repetsky, I. G. Vyshyvana,Y.Nakazawa,S. P. Kruchinin, S.Bellucci., Electron transport in carbon nanotubes with adsorbed chromium impurities.Materials (2019), 12, 524.

2.J.Bonca and S.Kruchinin (Eds). Nanostructured materials for the detection of CBRN. Springer, 2018, P.350 .

The authors thank the reviewer for their time and feedback. However, we decline to include these references in the revised manuscript, since they fall outside the scope of the paper. The material processed by the HiPerDiF machine is carbon fibre, and not nanotubes, with which they share only minor similarities.

Reviewer 3 Report

Reviewer Report:

The present manuscript entitled “Life Cycle Assessment of the High-Performance Discontinuous Fibre (HiPerDiF) technology and its operation in various countries” authored by Amy M. Fitzgerald et al. describes the environmental impacts of the machine using life cycle assessment methodology. The hypothetical operation of the machine across different European countries was also examined to understand the impacts associated with bulk material transport and electricity from different energy sources. Furthermore, the environmental impact showed an inverse correlation with the increased use of renewable sources for electricity generation due to a reduction in air pollutants from fossil fuel combustion. The outcomes indicated that the conceptual HiPerDiF second prototype (HiPerDiF 2G), and a second evaluation should be conducted on the optimized third-generation model (HiPerDiF 3G) recently completed at the National Composites Centre in Bristol, UK. The objective and justification of the work are clear, and the experimental work is significant. The study is very accurate and adequate, and thus, However, certain issues are detailed below which need to be addressed before its final acceptance in Sustainability.

Comment 1:  There are some typographical errors in the manuscript text, so authors need to correct them in the revised manuscript.

Comment 2:  The abstract should be edited. It must summarize well the obtained results.

Comment 3:  Provide the Graphical Abstract of the manuscript.

Comment 4: Figures 2, 3, and 10 quality is very poor, so improve the Figures resolution.

Comment 5: The conclusions section is too lengthy, should be shortened.

Author Response

Reviewer 3

Reviewer Report:

The present manuscript entitled “Life Cycle Assessment of the High-Performance Discontinuous Fibre (HiPerDiF) technology and its operation in various countries” authored by Amy M. Fitzgerald et al. describes the environmental impacts of the machine using life cycle assessment methodology. The hypothetical operation of the machine across different European countries was also examined to understand the impacts associated with bulk material transport and electricity from different energy sources. Furthermore, the environmental impact showed an inverse correlation with the increased use of renewable sources for electricity generation due to a reduction in air pollutants from fossil fuel combustion. The outcomes indicated that the conceptual HiPerDiF second prototype (HiPerDiF 2G), and a second evaluation should be conducted on the optimized third-generation model (HiPerDiF 3G) recently completed at the National Composites Centre in Bristol, UK. The objective and justification of the work are clear, and the experimental work is significant. The study is very accurate and adequate, and thus, However, certain issues are detailed below which need to be addressed before its final acceptance in Sustainability.

Comment 1:  There are some typographical errors in the manuscript text, so authors need to correct them in the revised manuscript. Thank you for picking up on this, and the formatting should be updated in this version.

Comment 2:  The abstract should be edited. It must summarize well the obtained results. A summary sentence explaining the result has been added.

Comment 3:  Provide the Graphical Abstract of the manuscript. The authors thank the reviewer for this comment. Currently MDPI do not require a graphical abstract.

Comment 4: Figures 2, 3, and 10 quality is very poor, so improve the Figures resolution. We thank the reviewer for identifying this, and we have replaced these images.

Comment 5: The conclusions section is too lengthy, should be shortened. We thank the reviewer for this feedback. The section starting on line 667 called “Interpretation and future considerations” is not a conclusion, but more of a discussion on the main points of the full study. The “Conclusion” starting on line 742 is a succinct section.

 

Round 2

Reviewer 1 Report

The revised version has improved and I recommend it for publication in the Sustainability journal.

Author Response

Dear the Editor and Reviewers,

Thank you for your feedback. The responses are:

1. Abstract: We thank the reviewer for their comments, but we deliberately decided not to include any numerical values in the abstract as it would be confusing when read out of its context. We have included a summary of the key findings and highlighted the novelty and relevance of this paper within the current literature.
2. Graphs: We thank the reviewer for raising this as a comment, and the figures have now been updated.
3. Graph axis units: We thank the reviewer for their comment, however this has been the standard of publication.
4. Table 1: Thank you and completed.
5. Avoid lumping references: We thank the reviewers for raising this comment, but lumped references are only present in the introduction where a handful of published articles verify the same point. Dedicating a separate sentence for each of the paper would make the introduction cumbersome, repetitive and difficult to read.
6. Conclusions: We thank the reviewer for their comment, and have made amendments appropriate to the study.
7. Reference style: We thank the reviewer for the comment, however the reference style has followed the one provided with the Sustainability Journal template.
8. Table 2: We thank the reviewer for their comment, and we have changed this.

Thank you for your time, and I look forward to hearing from you soon.

Best regards,
Amy Fitzgerald

Author Response File: Author Response.docx