Embodied Energy in Pyrolysis and Solvolysis Approaches to Recycling for Carbon Fiber-Epoxy Reinforced Composite Waste Streams

Round 1

Reviewer 1 Report

The embodied energy of carbon fiber reinforced plastics waste streams recycled via pyrolysis and solvolysis technologies was addressed in this study, and Some conclusions of engineering significance were obtained. The manuscript can be accepted after addressing the following question:

1. The specific features and characters of composite system are not well introduced or explained in the manuscript;
2. The origins of the data, and the relevant formulas need detailed introduction;
3. Conclusion needs to be concised

Author Response

Please see attached file.

Author Response File: Author Response.docx

Reviewer 2 Report

The work concerns the analysis of CFRP composite waste recycling by pyrolysis and solvolysis.The authors presented an interesting concept for the management of this waste, in line with the current trends in this field. Pyrolysis seems to be the most promising method of thermal conversion of various types of waste into an environmentally inert and valuable product from an energy point of view. It should be noted, however, that the work focuses excessively on technological aspects, material science aspects do not constitute the dominant thread of the article. The quantitative share between the material science analysis and the discussion of technology is debatable, therefore the work only to a limited extent falls within the scope of the subject matter of the Recycling magazine. This issue should therefore be examined by the Editor of the Special Issue. However, this does not change the general assessment that the article is important for the scientific community and concerns the current problems of managing complex materials, such as composites.

Detailed comments:

• The visualization of the pyrolysis process presented in Fig. 1 has a cognitive and didactic value, but, the multitude of information contained in this figure makes it difficult to interpret. This difficulty is all the greater because there is no marked direction of moving around the drawing. The use of dotted / dashed lines is not very convincing and gets lost in the excess of information. Therefore, it is suggested that the authors mark with arrows the successive stages of the process (as shown in the case of solvolysis) or visualize the successive stages of waste processing in a more simplified manner.
• The reference in line 122 is missing.
• The discussion of the results presented in Tables 3, 4 and 5 and in Figures 5, 6a and 6b is very sketchy and general. There is no in-depth analysis. The discussion in Section 8 regarding the above-mentioned tables and figures is insufficient.
• The authors use different units of mass interchangeably, namely both pounds (e.g., lines 30, 78, 187) and kg (e.g., lines 105, 114, 134, section 4.0). Authors should only use one unit system.

Author Response

Please see attached file.

Author Response File: Author Response.docx