Technologies and Innovations for Biomass Energy Production

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript provides an overview of biomass conversion technologies. It is a well-written and well-structured manuscript. The following are my comments:
1- Figure 1: In the figure, there are some biomass conversion technologies that are not mentioned, such as crushing, grinding, and drying in the physical technologies, and Torrefaction in the thermochemical technologies.

2- Figure 7: This figure should be provided in a higher quality version.

3- Section 2.1.3: The Gasification process requires oxidants or gasifying agents. I did not see any information about that, however.

4- Section 2.1.5: A description of catalytic torrefaction is needed here.

5- Section 2.2.1: Pyrolysis technology section should cover catalytic slow and fast pyrolysis in detail.

6- It would be useful if the authors provided more discussion of the effectiveness of presented technologies with a comparative approach, since this is a review paper.

Comments for author File: Comments.pdf

Fair enough.

Author Response

This manuscript provides an overview of biomass conversion technologies. It is a well-written and well-structured manuscript. The following are my comments:

1- Figure 1: In the figure, there are some biomass conversion technologies that are not mentioned, such as crushing, grinding, and drying in the physical technologies, and Torrefaction in the thermochemical technologies.

Response

• This has been addressed. The suggested methodologies have been added to Fig. 1 of the revised manuscript. Thank you for your comment.

2- Figure 7: This figure should be provided in a higher quality version.

Response

• This has been done as suggested. Figure 7 has been replaced with a higher quality image. Please see Figure 7 of the revised manuscript. Thank you for your comment.

3- Section 2.1.3: The Gasification process requires oxidants or gasifying agents. I did not see any information about that, however.

Response

• The oxygen, carbon dioxide, steam, and air gasifying agents are already mentioned in the gasification process discussion. Thank you for your comment.

4- Section 2.1.5: A description of catalytic torrefaction is needed here.

Response

• More information has been added. Thank you for your comment.

5- Section 2.2.1: Pyrolysis technology section should cover catalytic slow and fast pyrolysis in detail.

Response

• More information has been added. Thank you for your comment.

6- It would be useful if the authors provided more discussion of the effectiveness of presented technologies with a comparative approach, since this is a review paper.

Response

• This review already has showed the effectiveness of different technologies and how they differ, though they were discussed individually. Thank you for your comment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript "The Current Technologies and Innovations for Biomass Recycling" summarized the competitive advantages, potential environmental impacts, and challenges of different conversion technologies used for bioenergy production. The article was not very well organized, and most of the information was not new. I would suggest the author address the following concerns;

 (1) Title: The title was too big, and it needed to be more specific.

(2) Abstract: The current version lacked the conclusions. It should be concise and directly underscore the major and novelty of the findings.

(3) Introduction: The content was incomplete. Many core data about the bioenergy production market should be given in the Introduction. A brief introduction and the application scenarios of each conversion technology should be presented, including physical, biological, thermochemical, and biochemical.

(4) Biomass conversion technologies: (i) There are too many subheadings, which confused readers. Please rearrange. (ii) The content only listed the techniques. Their application scenarios should be further discussed. The pros and cons of these techniques should be discussed in detail. (iii) There were too many figures in this section, and they should be refined and merged, e.g., Fig. 1-4. (iv) The pictures were also not clear enough.

(5) Challenges, sustainability, and environmental benefits: This part is too general and too simple. Lack of comparative discussion and conclusion. Please rewritten.

(6) Conclusion: The conclusion should be rewritten. It should directly underscore the major and novelty of the findings. This part did not see the conclusion of this article.

Minor editing of English language required

Author Response

The manuscript "The Current Technologies and Innovations for Biomass Recycling" summarized the competitive advantages, potential environmental impacts, and challenges of different conversion technologies used for bioenergy production. The article was not very well organized, and most of the information was not new. I would suggest the author address the following concerns;

• Title: The title was too big, and it needed to be more specific.

 Response

• This has been addressed. The title has been re-written and it’s more specific. Thank you for your comment. 

• Abstract: The current version lacked the conclusions. It should be concise and directly underscore the major and novelty of the findings.

Response

• This has been addressed. The abstract has been re-written. Please see the abstract section of the revised manuscript. Thank you for your comment.

• Introduction: The content was incomplete. Many core data about the bioenergy production market should be given in the Introduction. A brief introduction and the application scenarios of each conversion technology should be presented, including physical, biological, thermochemical, and biochemical.

Response

• The focus of this review is describing the various technologies associated with biomass conversion for bioenergy production. The information about the core data about the bioenergy production market has recently been published and we do not intend to repeat this information as it’s beyond the scope of our present review. Please see the following articles for more details. Energies 2022, 15, 9601. https://doi.org/10.3390/en15249601; However, we intend to add this information in our next submission. This work is currently on-going: Title: The fate and application of bioenergy resource derived from biomass. Thank you for your comment.
• Biomass conversion technologies: (i) There are too many subheadings, which confused readers. Please rearrange. 

Response

• This has been addressed. The multiple sub-sections have been corrected. Please see page the revised manuscript. Thank you for your comment.

 (ii) The content only listed the techniques. Their application scenarios should be further discussed. The pros and cons of these techniques should be discussed in detail.

Response

• The application scenarios will be communicated in our next submission (Title: “The fate and applications of bioenergy resource derived from biomass”). The research on this is currently on-going. The pros and cons of the technologies are summarized in Table 2-5. Thank you for your comment.

(iii) There were too many figures in this section, and they should be refined and merged, e.g., Fig. 1-4.

Response

• According to the mdpi sustainability journal’s instruction for authors, All Figures, Schemes and Tables should be inserted into the main text close to their first citation and must be numbered following their number of appearance (Figure 1, Scheme I, Figure 2, Scheme II, Table 1, etc.). We believe complying with the journal’s requirement is vital for the transformation of the manuscript to a publishable form. Please see https://www.mdpi.com/journal/sustainability/instructions#figures for details. Thank you for your comment.

 (iv)  The pictures were also not clear enough.

Response

• Clearer images of high qualities have been provided. Thank you for your comments.

• Challenges, sustainability, and environmental benefits: This part is too general and too simple. Lack of comparative discussion and conclusion. Please rewritten.

Response

• The challenges, sustainability, and environmental benefits has been re-written. Please see the section of the revised manuscript. Thank you for your comments.

• Conclusion: The conclusion should be rewritten. It should directly underscore the major and novelty of the findings. This part did not see the conclusion of this article.

Response

• The conclusion has been re-written. Please see the conclusion section of the revised manuscript Thank you for your comments.

Reviewer 3 Report

Repeated work.

Repeated idea of the manuscript. The content and the style are very similar to the published literature.

You may have a view with the following: https://www.hindawi.com/journals/jchem/2020/5024369/

Repeated work 

Author Response

Repeated work. Repeated idea of the manuscript. The content and the style are very similar to the published literature. You may have a view to the published literature. https://www.hindawi.com/journals/jchem/2020/5024369/

Response

• Our current work has no similarity in focus, content and style of the suggested published literature. The abstract from the published work stated clearly:

Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic residues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much attention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap and abundantly resources can reduce global warming owing to their less polluting nature. +e low-quality biomass and high ash content of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Thererefore, it is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author information, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The objective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/biomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the composition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the operating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and chemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/sewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique. Furthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study will provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends.

Our abstract reads:

Biomass is considered one of the prospective alternatives to energy and environmental challenges. The use of biomass as bioenergy has gained global interest due to its environmentally benign, renewable, and abundant characteristics. Numerous conversion technologies have been developed over time to convert biomass into various energy products. This review presents a summary of the different biomass conversion technologies used for bioenergy production. These include thermochemical, biological, physical, biochemical, and hybrid system technologies. It summarizes the production of different bioenergy products such as bio-oil, biodiesel, and fuel through the various conversion technologies. The competitive advantages, potential environmental impacts, and challenges of these biomass conversion technologies are discussed. The recycling of biomass can solve a lot of current energy challenges. However, the conversion technologies exhibit some challenges relative to upscaling and commercialization due to their immense operational and investment expenses and high energy usage.

Obviously there’s no correlation in similarity repeatability in our current submitted work and the claimed published work. Thank you for your comment.

Round 2

Reviewer 2 Report

The authors have addressed my concerns. It looks OK.

Minor editing of English language required