Development of CO2 Absorption Using Blended Alkanolamine Absorbents for Multicycle Integrated Absorption–Mineralization
Round 1
Reviewer 1 Report
The authors' article is devoted to an important and topical issue related to the use of carbon dioxide absorption with the use of various absorbents.
Climate change driven by greenhouse gas emissions is becoming a global issue worldwide. By the end of the century, the concentration of carbon dioxide is expected to increase by about 2 times. Despite the purposeful growth of solar and wind energy, there is still no competitive alternative to burning hydrocarbon fuels. There are three most common industrial methods for extracting carbon dioxide from combustion products: physical (in particular, the method of water absorption), chemical (method of absorption with an aqueous solution of monoethanolamine or diethanolamine and adsorption. There are other technologies for extracting carbon dioxide, but they have not found wide industrial application. In In this regard, technologies for capturing and storing carbon in the form of carbon dioxide are recognized as critical to curbing the rise in temperature on the planet. The amine purification method used, due to its high cost, has not found wide application in industry.However, new technological solutions (for example, the use of enzymes, membranes and chemisorbents) will help reduce the cost of this method and its widespread implementation.
Thus, this problem is relevant, both from a resource-saving, and from an environmental and economic point of view.
The studies presented in the paper are undoubtedly of interest to readers in the field under consideration.
However, it would be necessary to clarify a number of comments that are available to the article:
1. In the article in sections 1 and 2, a more detailed analysis of the known absorption methods used in the article should have been carried out.
2. Have you compared the developed scheme for connecting experimental equipment and devices for multi-cycle complex absorption-mineralization (Figure 1) with the analogues used? Should the advantages of the scheme used be emphasized more clearly?
3. Is it possible to conduct studies with a wider variation of parameters than shown in section 2.3? Or do these parameter changes give a greater effect?
4. Very important data are presented in the graphs of Figure 2. It would be necessary to give mathematical models of the parameters under study, allowing the calculation and prediction of the output value.
5. In the Discussion section, a more detailed analysis could be made of the methods used around the world to improve resource efficiency and improve carbon capture and use by evaluating the use of mixed alkanolamine absorbents.
6. Are there any patents on the methods used in the article and is it planned to test the results obtained on other similar objects?
Author Response
Journal: Minerals, MDPI
Manuscript ID: minerals-2294807
Paper title: Development of multicycle integrated absorption–mineralization for CO2 utilization using MEA-based blended absorbents.
Dear Editors and Reviewers.
We greatly appreciated for the reviewers’ comments and suggestions. The proposed comments and questions are valuable and helpful for us to revisit and improve the quality of our paper. When preparing the revised manuscript, be sure to address the following additional corrections. In addition, we would like to thank you and the reviewers for their effort in providing comments, concerns and suggestions on our manuscript. Revisions in the manuscript are shown in blue color. In accordance with the reviewers’ comments and suggestions, the adjusted contexts are marked with text highlight yellow color. We hope that the revisions in the manuscript and accompanying responses are adequately acceptable and sufficient to make our manuscript suitable for publication. Thank you for your consideration.
Sincerely,
Chanakarn Thamsiriprideeporn and coauthors.
Responses to comments from Reviewer 1
General comments:
The authors' article is devoted to an important and topical issue related to the use of carbon dioxide absorption with the use of various absorbents.
Climate change driven by greenhouse gas emissions is becoming a global issue worldwide. By the end of the century, the concentration of carbon dioxide is expected to increase by about 2 times. Despite the purposeful growth of solar and wind energy, there is still no competitive alternative to burning hydrocarbon fuels. There are three most common industrial methods for extracting carbon dioxide from combustion products: physical (in particular, the method of water absorption), chemical method of absorption with an aqueous solution of monoethanolamine or diethanolamine and adsorption. There are other technologies for extracting carbon dioxide, but they have not found wide industrial application. In In this regard, technologies for capturing and storing carbon in the form of carbon dioxide are recognized as critical to curbing the rise in temperature on the planet. The amine purification method used, due to its high cost, has not found wide application in industry. However, new technological solutions (for example, the use of enzymes, membranes and chemisorbents) will help reduce the cost of this method and its widespread implementation. Thus, this problem is relevant, both from a resource-saving, and from an environmental and economic point of view. The studies presented in the paper are undoubtedly of interest to readers in the field under consideration.
Response: We sincerely appreciate the reviewers' comments and suggestions. We can evaluate our manuscript and continue to improve it.
Detailed comments:
Q1: In the article in sections 1 and 2, a more detailed analysis of the known absorption methods used in the article should have been carried out.
A1: For your suggestions, it has been very helpful in improving our introduction and experimental sections. We added the further information of amine absorption in the revised manuscript (Line 56-68 and 196-197).
Q2: Have you compared the developed scheme for connecting experimental equipment and devices for multi-cycle complex absorption-mineralization (Figure 1) with the analogues used? Should the advantages of the scheme used be emphasized more clearly?
A2: We were sorry for the unclear explanation. In our design and operation of the multicycle integrated absorption–mineralization (multicycle IAM), we have incorporated two key benefits of conventional CO2 amine-based removal and CO2 utilization using brine solution. The conventional CO2 amine-based removal process involves recycling the amine absorbent to optimize the CO2 capture performance [1-4]. However, this process typically operates at high temperatures, exceeding 100°C for amine regeneration [3,4]. The waste brine utilized to desorb CO2 from amine as well as to enhance CO2 sequestration through mineralization. This approach allowed for operation at room temperature and atmospheric pressure, with the precipitation of carbonates increasing CO2 utilization [5].
We have combined the advantages of amine absorbent recycling and brine mineralization in our multicycle IAM. This approach enables us to expand carbonate production while operating at ambient temperature and pressure conditions, with optimal utilization of the amine absorbent. We summarized and added the further advantages of multicycle IAM in the manuscript (Lines 76-86).
Ref:
[1] Bernhardsen, I. M., and Knuutila, H. K. (2017). A review of potential amine solvents for CO2 absorption process: Absorption capacity, cyclic capacity and pKa. International Journal of Greenhouse Gas Control, 61, 27-48.
[2] Kim, S., Shi, H., and Lee, J. Y. (2016). CO2 absorption mechanism in amine solvents and enhancement of CO2 capture capability in blended amine solvent. International Journal of Greenhouse Gas Control, 45, 181-188.
[3] Kohl, A. L., and Nielsen, R. (1997). Gas purification. Elsevier.
[4] Kohl, A. L. (1985). Alkanolamines for hydrogen sulfide and carbon dioxide removal. Gas purification, 29-35.
[5] Zevenhoven, R., and Fagerlund, J. (2010). Mineralisation of carbon dioxide (CO2). In Developments and innovation in carbon dioxide (CO2) capture and storage technology (pp.433-462). Woodhead Publishing.
Q3: Is it possible to conduct studies with a wider variation of parameters than shown in section 2.3? Or do these parameter changes give a greater effect?
A3: Indeed, we performed our experiment which further study the advantages of blending alkanolamine absorbent in the section of absorption of multicycle IAM.
Our study aimed to investigate the benefits of blending alkanolamine absorbent in the absorption stage of multicycle IAM. Experimental procedures were conducted to compare purified MEA with blended MEA under identical conditions (20-25°C, 1 atm). In order to maintain consistency, the concentration of MEA was kept constant throughout the experiment [6]. We maintain the belief that a broader range of amine concentrations in our study would yield more comprehensive outcomes. Nevertheless, given the preliminary nature of our available data, we have opted to experiment using concentration ratios that can be compared and analyzed.
Ref:
[6] Thamsiriprideeporn, C., and Tetsuya, S. (2022). Effects of Alkanolamine Absorbents in Integrated Absorption–Mineralization. Minerals, 12(11), 1386.
Q4: Very important data are presented in the graphs of Figure 2. It would be necessary to give mathematical models of the parameters under study, allowing the calculation and prediction of the output value.
A4: Thank you very much for your suggestion and felt sorry for unclear use of phrases or sentences. We added the calculation of CO2 accumulation in the revised manuscript (Line 300-307).
Q5: In the Discussion section, a more detailed analysis could be made of the methods used around the world to improve resource efficiency and improve carbon capture and use by evaluating the use of mixed alkanolamine absorbents.
A5: Thank you for your insightful comment. We added more details of blended amine for CO2 absorption to improve the absorption efficiency in the revived manuscript (Line 612-626).
The blended alkanolamine absorbent is widely used in current CO2 removal technology because it is a simple and cost-effective method that can increase the efficiency of CO2 capture, especially in multicycle IAM. The blended absorbent is used to improve the CO2 capture because the proportion of amine in absorbent was also higher. Therefore, the selectivity of CO2-amine in the blended absorbent increases, resulting in a higher CO2 absorption per unit (conversion efficiency) and reduced the loss of amine in system (degradation efficiency) [7,8].
Ref:
[7] Zhang, J., Nwani, O., Tan, Y., and Agar, D. W. (2011). Carbon dioxide absorption into biphasic amine solvent with solvent loss reduction. Chemical Engineering Research and Design, 89(8), 1190-1196.
[8] Zhuang, Q., and Clements, B. (2018). CO2 capture by biphasic absorbent–absorption performance and VLE characteristics. Energy, 147, 169-176.
Q6: Are there any patents on the methods used in the article and is it planned to test the results obtained on other similar objects?
A6: Thank you for the helpful suggestions. We have not yet filed a patent, but we have a plan to improve the experimental methodology for future patent filing.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments for author File: Comments.pdf
Author Response
Journal: Minerals, MDPI
Manuscript ID: minerals-2294807
Paper title: Development of multicycle integrated absorption–mineralization for CO2 utilization using MEA-based blended absorbents.
Dear Editors and Reviewers.
We greatly appreciated for the reviewers’ comments and suggestions. The proposed comments and questions are valuable and helpful for us to revisit and improve the quality of our paper. When preparing the revised manuscript, be sure to address the following additional corrections. In addition, we would like to thank you and the reviewers for their effort in providing comments, concerns and suggestions on our manuscript. Revisions in the manuscript are shown in blue color. In accordance with the reviewers’ comments and suggestions, the adjusted contexts are marked with text highlight yellow color. We hope that the revisions in the manuscript and accompanying responses are adequately acceptable and sufficient to make our manuscript suitable for publication. Thank you for your consideration.
Sincerely,
Chanakarn Thamsiriprideeporn and coauthors.
Responses to comments from Reviewer 2
General comments:
Response: We highly appreciate your comments and suggestions, which will assist us to improve our manuscript. We organized the sections of the result, discussion, and conclusion for this revised manuscript.
Detailed comments:
Q1: Please use the literature background on cleaner production/sustainability to broaden the manuscript foundation, which is important in capturing the attention of the prospective reader.
A1: Thanks for reminding us about literature background. We were carefully checked and improved our revised manuscript.
Q2: In your abstract, emphasize the scientific value of your paper. Please read the articles we've written about models. Your abstract should clearly state the essence of the problem, what you did, and what you discovered and recommended. This would assist a prospective abstract reader in deciding whether or not to read the entire article.
A2: We applicated for your insightful comments, which have been helpful in improving our manuscript (Line 13-20 and 23-25).
Q3: Your discussion and conclusions do not establish a strong correlation with cleaner production, sustainability, or environmental concerns. Please connect your empirical findings to a broader and more in-depth review of the literature.
A3: We improved our content of empirical findings according to your comments (Section 4.4 and Table S1). We really appreciate your help.
The criteria for selecting the appropriate alkanolamine absorbent in multicycle IAM are depended on CO2 absorption capacity, conversion efficiency, absorbent degradation, toxicity, and cost, as following Equation 9.
| Appropriate blended absorbent = (W1 x CO2 absorption factor) + (W2 x Conversion factor) + (W3 x Degradation factor) + (W4 x Toxic factor) + (W5 x Cost factor) |
(9) |
The CO2 absorption factor represents the fraction of the blended alkanolamine absorbent's experimemtal CO2 absorption capacity to its nominal CO2 absorption capacity [50]. The degradation factor accounts for the degradation of the amine solution over time due to chemical reactions and impurities [54-56] and can be estimated using Equation 7. The conversion factor represents the fraction of CO2 that is converted into a stable carbonate after absorption [53] and can be estimated using Equation 8. The toxic factor indicates the level of harm posed to humans [61,62], while the cost factor represents the cost of the amine solution [63-65]. W1, W2, W3, W4, and W5 are weights assigned to each variable. These factors range from 0 to 1, with 0 indicating no effect and 1 indicating the greatest effect.
Q4: Please ensure that your conclusions section emphasizes the scientific value of your paper and/or the applicability of your findings. Highlight the uniqueness of your mineralization research. Discuss in detail the previous studies to which you are referring. What research gaps and contributions exist? What minerals were obtained during the study in relation to carbon capture, utilization, and storage (CCUS)?
The conclusion section lacks some perspective on future research work and quantifies main research findings. Please discuss the implications of your research in your conclusions. Discussions and conclusions should be more in-depth; it would be more interesting if the authors focused more on the significance of their findings in terms of the interrelationship between the obtained results and sustainable development/cleaner production in the sector context, and the barriers to doing so, as well as the real-world consequences of changing the observed situation.
A4: We apologized to use unclear explanation. We clarified our research contribution in the conclusion section of the revised manuscript (Section 5).
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper reported a IAM technology for CO2 emission reduction. The topic is intersting, and the manuscript is overall well writen. It can be accepted for publication in Minerals after minor revisions.
1. The title is not precise enough. For the first sight, I thought it was a review article.
2. In the introduction part, more content about CO2 mineralization is suggested to be added. Here are some good papers, and the author are suggested to cite these papers. Chemical Engineering Journal 416 (2021) 129093;Minerals 2021, 11(3), 274
Author Response
Journal: Minerals, MDPI
Manuscript ID: minerals-2294807
Paper title: Development of multicycle integrated absorption–mineralization for CO2 utilization using MEA-based blended absorbents.
Dear Editors and Reviewers.
We greatly appreciated for the reviewers’ comments and suggestions. The proposed comments and questions are valuable and helpful for us to revisit and improve the quality of our paper. When preparing the revised manuscript, be sure to address the following additional corrections. Revisions in the manuscript are shown in blue color. In accordance with the reviewers’ comments and suggestions, the adjusted contexts are marked with text highlight yellow color. We hope that the revisions in the manuscript and accompanying responses are adequately acceptable and sufficient to make our manuscript suitable for publication. Thank you for your consideration.
Sincerely,
Chanakarn Thamsiriprideeporn and coauthors.
Responses to comments from Reviewer 3
General comments:
This paper reported a IAM technology for CO2 emission reduction. The topic is interesting, and the manuscript is overall well written. It can be accepted for publication in Minerals after minor revisions.
Response: We sincerely appreciate the reviewers' comments and suggestions. We can evaluate our manuscript and continue to improve it.
Detailed comments:
Q1: The title is not precise enough. For the first sight, I thought it was a review article.
A1: We improved our title according to your comments. We really appreciate your help.
Q2: In the introduction part, more content about CO2 mineralization is suggested to be added. Here are some good papers, and the author are suggested to cite these papers. Chemical Engineering Journal 416 (2021) 129093; Minerals 2021, 11(3), 274
A2: Thank you for your suggestions, these references were added.
Author Response File: Author Response.pdf
Reviewer 4 Report
I think this is a well written article describing the CO2 removal technique. I only have minor comments and would recommend it to be accepted after minor revision. My biggest concern on the manuscript is that the authors conclude carbonates as a single mineral and a brief description of different carbonate minerals should be provided.
Detail comments:
Line 51-52: It should be “metal cations” instead of “mineral ions”.
Line 76-77: I think it should be explained here what kind of advantages there are.
Author Response
Journal: Minerals, MDPI
Manuscript ID: minerals-2294807
Paper title: Development of multicycle integrated absorption–mineralization for CO2 utilization using MEA-based blended absorbents.
Dear Editors and Reviewers.
We greatly appreciated for the reviewers’ comments and suggestions. The proposed comments and questions are valuable and helpful for us to revisit and improve the quality of our paper. When preparing the revised manuscript, be sure to address the following additional corrections. In addition, we would like to thank you and the reviewers for their effort in providing comments, concerns and suggestions on our manuscript. Revisions in the manuscript are shown in blue color. In accordance with the reviewers’ comments and suggestions, the adjusted contexts are marked with text highlight yellow color. We hope that the revisions in the manuscript and accompanying responses are adequately acceptable and sufficient to make our manuscript suitable for publication. Thank you for your consideration.
Sincerely,
Chanakarn Thamsiriprideeporn and coauthors.
Responses to comments from Reviewer 4
General comments:
I think this is a well written article describing the CO2 removal technique. I only have minor comments and would recommend it to be accepted after minor revision. My biggest concern on the manuscript is that the authors conclude carbonates as a single mineral and a brief description of different carbonate minerals should be provided.
Response: We sincerely appreciate the reviewers' comments and suggestions. We can evaluate our manuscript and continue to improve it.
Detailed comments:
Q1: It should be “metal cations” instead of “mineral ions” (Line 51-52).
A1: The statement has been corrected in the revised manuscript.
Q2: I think it should be explained here what kind of advantages there are (Line 76-77)
A2: We summarized and added the further advantages of multicycle IAM in the manuscript (Lines 76-86).
In the multicycle IAM, we have incorporated two key benefits of conventional CO2 amine-based removal and CO2 utilization using brine solution. The conventional CO2 amine-based removal process involves recycling the amine absorbent to optimize the CO2 capture performance [1-4]. However, this process typically operates at high temperatures, exceeding 100°C for amine regeneration [3,4]. The waste brine utilized to desorb CO2 from amine as well as to enhance CO2 sequestration through mineralization. This approach allowed for operation at room temperature and atmospheric pressure, with the precipitation of carbonates increasing CO2 utilization [5].
We have combined the advantages of amine absorbent recycling and brine mineralization in our multicycle IAM. This approach enables us to expand carbonate production while operating at ambient temperature and pressure conditions, with optimal utilization of the amine absorbent.
Ref:
[1] Bernhardsen, I. M., and Knuutila, H. K. (2017). A review of potential amine solvents for CO2 absorption process: Absorption capacity, cyclic capacity and pKa. International Journal of Greenhouse Gas Control, 61, 27-48.
[2] Kim, S., Shi, H., and Lee, J. Y. (2016). CO2 absorption mechanism in amine solvents and enhancement of CO2 capture capability in blended amine solvent. International Journal of Greenhouse Gas Control, 45, 181-188.
[3] Kohl, A. L., and Nielsen, R. (1997). Gas purification. Elsevier.
[4] Kohl, A. L. (1985). Alkanolamines for hydrogen sulfide and carbon dioxide removal. Gas purification, 29-35.
[5] Zevenhoven, R., and Fagerlund, J. (2010). Mineralisation of carbon dioxide (CO2). In Developments and innovation in carbon dioxide (CO2) capture and storage technology (pp.433-462). Woodhead Publishing.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
It seems to me that Authors have addressed on issues of suggested reviewers. Therefore it can be published in the present form.
