Using a Low-Temperature Pyrolysis Device for Polymeric Waste to Implement a Distributed Energy System

Round 1

Reviewer 1 Report (Previous Reviewer 3)

By comparing the original manuscript and the resubmitted improved manuscript I can state that:

- authors significantly improved language, yet some typos are still to be corrected

- formal and formatting issues are now mostly OK; artwork quality should be improved still (see Table 1 with embedded small figures and Figure 3 - in both cases the resolution is low)

- literature survey was further elaborated and the sense of actuality and practical value can be clearly perceived

- method description was rewritten, enriched by requested information and is now clear and understandable

- results presentation contains relevant information

What remains to be dealt with is Discussion. Even though improved ale elaborated compared to original submission and conducts comparison to other already operating plats, referencing should be improved. Take Table 4: The authors added a note stating (if I understand this correctly) that the information was extracted from the waste treatment plants´ websites. If so, what does the authors prevent from listing those websites among references? In addition, the discussion in 4.4. and 4.5. is interesting but contains a lot of information which should be referenced to make the text more academic rather than a plain narrative.

I recommend the authors conducting a further improvement of Discussion section as a part of major revision of the manuscript.

Author Response

By comparing the original manuscript and the resubmitted improved manuscript I can state that:

- authors significantly improved language, yet some typos are still to be corrected

- formal and formatting issues are now mostly OK; artwork quality should be improved still (see Table 1 with embedded small figures and Figure 3 - in both cases the resolution is low)

• Thanks to the reviewer's suggestion, the authors have split Table 1 into Table 1 (retaining production information) and Figure 3 (new figure), and greatly improved the resolution of all figures (including new figure 4). Most typos in the manuscript have been corrected. If there are further requirements, we can make further improvements.

 

- literature survey was further elaborated and the sense of actuality and practical value can be clearly perceived

- method description was rewritten, enriched by requested information and is now clear and understandable

- results presentation contains relevant information

• Thanks to the reviewers for their comments which made our hard work better reflected in this manuscript.

 

What remains to be dealt with is Discussion. Even though improved ale elaborated compared to original submission and conducts comparison to other already operating plats, referencing should be improved. Take Table 4: The authors added a note stating (if I understand this correctly) that the information was extracted from the waste treatment plants´ websites. If so, what does the authors prevent from listing those websites among references? In addition, the discussion in 4.4. and 4.5. is interesting but contains a lot of information which should be referenced to make the text more academic rather than a plain narrative.

 

• Thanks to the reviewers for their criticisms and suggestions, which made our research more rigorous and complete. The authors have improved the information citations in Table 4. Due to unfamiliarity with the citation format of data and documents from the web sources (including in Japanese and traditional Chinese), they were not presented in previous versions of the manuscript. Relevant citation information is now provided in the #51 reference.
  The authors also improve the discussion in 4.4. and 4.5., reformulating and citing the literature, on enhancing grid resilience and applying decentralized energy supply systems to different domain requirements. Thanks again for your valuable advice.

 

I recommend the authors conducting a further improvement of Discussion section as a part of major revision of the manuscript.

• The authors agree with the reviewer's comments to reorganize the manuscript to improve the presentation of figures and tables, and to substantially improve the informative statements in the Discussion.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

The authors have significantly improved the quality of the submitted manuscript. However, the content is still in essence very poor and could be much improved. The results presented are predictable and the discussion of the results leaves much to be desired. It is advisable to include improvements in the discussion and quality of the images presented. In addition, some minor changes are added:

Figure 2 is moved and is not visible.

There are errors in the units, be careful with subscripts and always use the international system.

The organisation of the manuscript leaves much to be desired

Figure 3 is very poor and there is no discussion of the results.

The results obtained are of little relevance

The conclusions need to be significantly expanded and improved.

Author Response

The authors have significantly improved the quality of the submitted manuscript. However, the content is still in essence very poor and could be much improved. The results presented are predictable and the discussion of the results leaves much to be desired. It is advisable to include improvements in the discussion and quality of the images presented. In addition, some minor changes are added:

• Thank you very much for the reviewer's guidance. The authors have reorganized the structure of the article, explained the innovation and applications of the research results, and cited relevant information and literature about the resilience of the power grid and the difference in energy demand in different fields in the discussion.

 

Figure 2 is moved and is not visible.

• Thanks for the reminder, maybe it was lost during file conversion. We have provided a clearer Figure 2 to illustrate the operating structure of the low-temperature pyrolysis system.

 

There are errors in the units, be careful with subscripts and always use the international system.

• Thanks to the reviewer for your careful review, we have corrected the subscripts unit of the dynamic viscosity and the heating value unit to the international system.

 

The organisation of the manuscript leaves much to be desired

• The authors have restructured the organization of the manuscript and strengthened the highlights, and thank the reviewer for making our study more scientific sound.

 

Figure 3 is very poor and there is no discussion of the results.

• The authors reproduce Figure 3 (as the Figure 4 in revision) and illustrate the continuous production mode with step feeding. Different from the batch experiments, automated process control can improve the feeding speed, ambient reaction conditions and product output removal in a continuous operation, making the production process more economical and efficient.

 

The results obtained are of little relevance

• Thanks to the reviewer for your comments, the authors have improved the presentation and discussion of the results and provided richer relevant information in the manuscript. Including the difference between high-temperature pyrolysis process and low-temperature pyrolysis process in terms of the conversion efficiency and the composition of products.

 

The conclusions need to be significantly expanded and improved.

• The authors have reworded the conclusions to emphasize the purpose of this study and to clarify the results of implementation to provide an affordable, clean, accessible renewable energy applications while reducing the environmental impact of modern life.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report (New Reviewer)

The authors have made all the changes proposed by the reviewer and the article has been significantly improved for publication in the journal.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The authors focused on the waste disposal and waste-to-energy investigation, which is a meaningful research topic nowadays. The proposed method is to use low-temperature pyrolysis to convert waste to useful oil. However, based on the paper quality, I am afraid I cannot accept the paper as the current version. Some comments are left here:

1. Please concise the paper and use succinct statements throughout the paper. Avoid long-page redundant contents.

2. Try to improve the method description. The paper should disclose the contents in detail as much as it can, so that others can repeat. After reading the paper, I am still not very clear on the pyrolysis method, how did it work? What is the difference between the method used here and others reported in the literature. Such method is not unique. And mobile module is also not well-described. Flowchart diagram is suggested.

3. Results presented here are too poor. Only purity, oil yield are presented. Is that all the data obtained by this study? Which kind of waste was used to generate the data? Why not category the waste and analyze and compare the waste-to-energy efficiency, oil produciton, oil quality and costs, (so on) related to the waste disposal? A good journal paper should have enough solidated data.

4. Can the authors set some standard or propose some evaluation criteria for the comparison with other technologies for a fair and better comparison?

5. Give more quantified data in both Abstract and Conclusions.

6. Last but not least, please think about the novelty of such study. 

Reviewer 2 Report

The manuscript entitled “Mobile Module with Low-Temperature Pyrolysis of Waste Plastics to Implement Distributed Energy System” studied the mobile application of low-temperature microwave pyrolysis of plastic waste to oil. To address the disposable waste and meet the energy demand and advocated the use of waste plastic oil in generators. However, some minor mistakes need to be corrected before resubmission. The following are the main points to be improved:

 

Comments and Suggestions for Authors

1. It’s difficult to understand sentences that are too long and have grammatical mistakes.

2. Abbreviation list and highlights are missing and must be provided.

3. The temperature selected was182.1°C; why? And what is the temperature effect other than the selected temperature? And last, the pressure is not specified.

4. The chemical analysis of mixed and shredded plastic waste is missing.

5. The economic evaluation is not appropriate. The WPO comparison with solar and wind is also inappropriate. The efficiency calculation is missing. It is better to provide product price, waste price, waste handling charges and pros and cons related terms of the economic factor.

6. The efficacy of WPO is clear but not comparable.

7. The terms of comparison of LTD hosts with different waste recycling plants are unclear.

8. The manuscript is written in general form; more technical details should be included.

9. It is better to split figure 3 into two different figures.

 

10. Is the washer, crusher and extruder included in the LTD host?

Reviewer 3 Report

The presented manuscript is a report on microwave-assisted pyrolysis of mixed plastic waste experiments. As such, the chosen topic is relevant for Sustainability journal and the intent of the authors to develop a functional and efficient modular waste processing unit is commendable.

The manuscript starts with a decent Introduction, managing to highlight the topic actuality and containing an adequate number of references. However, very few references are made on the particular topic of “microwave-assisted pyrolysis”, despite the vast amount of recent literature (both review and experimental papers) dedicated to it. Thus, the sense of relevance of the submitted manuscript is doubtful.

Experimental part lacks a more detailed equipment description along with key design parameters of used equipment. Feed characteristics (composition, proximate, ultimate analysis, other important parameters) is missing, limiting the relevance of obtained results. The fact that only two experiments were performed and the whole Results and Discussion part uses the scarce results of two experiments only, disqualifies the manuscript from further consideration for publishing. It is simply unscientific to build just of two experiments and the relevance of obtained results plus that of the related discussion is very limited.

Discussion part lacks any analytical and quantitative approach, except for comparing installed waste processing capacities and their specific energy production. Not a single word is said about heat and power cogeneration.

 

Taking into account the above findings, my recommendation is to reject the paper. Experimental part is completely insufficient; results and discussion are weak, based on two single experimental runs. This is a situation, where major revision, however thorough, would not suffice to improve the manuscript quality. If the authors feel they can deal with my objections in a thorough way, they can produce a new manuscript and submit it. Attached is a list of queries that might help them in this task.

 

List of queries

English needs polishing by a native or certified speaker. Often, there is a mix of tenses used which worsens the text flow and makes the understanding of what was meant by the given text passages more difficult.

 

Literature is sufficiently rich, covering 60+ sources, combining journal articles and books, with journals being issued by several publishing houses. Literature is contemporary, strengthening the sense of manuscript actuality. Authors are encouraged to unify the References section format (capital letters in journal names…). Some references (Nr. 5 and 15 as examples) are incomplete, please provide full bibliographic details for all references if possible.

 

Study novelty must be emphasized. Microwave-assisted pyrolysis has already been studied in the recent past. Just a quick survey in ScienceDirect with “microwave-assisted pyrolysis” yielded over 13 thousand records, out of which over 5000 records are original articles. Lines 130 to 139 of the manuscript are insufficient as novelty claim. Authors need to assess the current literature (experimental papers) and state what contribution their study conveys above what is already known from experimental papers.

 

Line 96: use of lumped references should be avoided. If possible, state the contribution of each study cited, separately.

 

Figure 2 should be improved in terms of resolution. The same applies to Figure 3a.

 

Part 3.2. and 3.3 – more construction and design details should be provided, or a reference to suitable data source or repository containing them should be made.

 

Part 3.4 Is entirely insufficient. Feed properties are missing. Without stating and discussing feed properties, the whole experimental and results sections cannot be used beyond a mere case-study results. Moreover, two different experiments without repetition are entirely insufficient to make any relevant conclusions.

 

Table 1 and elsewhere in the manuscript – do use of upper and lower indices wherever applicable.

Line 242, 243, 251 and elsewhere: possible physical units confusion: Total produced power is given in kWh instead of KW. Please, do distinguish clearly between output (kW) and energy amount produced (kWh), or amount of energy produced per unit feed (kWh/kg).

 

Part 5 Discussion: Lacks proper references and the discussion must be enriched. And, even if references are made (see Table 2), they are omitted from References list. Make sure all references are listed in References list.

 

Part 5.3 and Table 2: It should be clearly stated whether the plants listed in Table 2 do, or do not cogenerate useful heat. If they do, comparing electricity outputs only is unfair.

 

Part 5.6 is very general, lacks any quantification and does not manage to clearly link the study outputs with topics of circular economy and sustainability.