Influence of the Adsorption Bed Composition on the Low-Pressure Fluidization

Round 1

Reviewer 1 Report

 I do not feel the quality of the manuscript is sufficient to meet the required standard of the current journal. Consequently, I propose to decline the manuscript.
Section 3 is written like an experimental report. There is little in depth discussion or comparison with the findings of other similar studies - not a single reference is mentioned in the section. There are no experimental errors or analyses.

Author Response

Comment:

I do not feel the quality of the manuscript is sufficient to meet the required standard of the current journal. Consequently, I propose to decline the manuscript.

Section 3 is written like an experimental report. There is little in depth discussion or comparison with the findings of other similar studies - not a single reference is mentioned in the section. There are no experimental errors or analyses.

Answer:

Thank you for your comments and suggestions. The manuscript was revised according to the comments of all reviewers.

The introduced modification significantly increases the overall quality of the manuscript and especially emphasizes the novelty of the presented research and its contribution to the development of knowledge regarding the adsorption research technology. Section 3 was supplemented with additional information constituting the in-depth discussion of the findings.

 

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

Reviewer 2 Report

Review

Manuscript Number: processes-2362613

Full Title: Influence of the adsorption bed composition on the low-pressure fluidization

Comments and Suggestions for Authors

l  General comments:

- Bibliography is enough, actual and relevant;

- English needs revision;

- Subject is interesting and actual.

l  Detailled comments:

(1)   Subject is actual and very interesting. English must be improved. Some sentences are confuse and some spell check is required.

(2)   Please pay more effort to improve the paper so that it addresses the following points sufficiently.

²  added values to previous researches

²  logical connections between sections for chapter 2

(3)   Abstract should describe the importance of the research and validation method, and key results obtained could be the added values to the knowledge in the subject. If these points are correct, please recorganize and improve the contents to be centralised on this points.

(4)   In figure 1 and 2, not only should the pictures of the experimental system be shown, but also the performance parameters and structural parameters of the test equipment should be illustrated.

(5)   In section 2.2, the adsorption bed was composed of silica gel supplied by Sigma-Aldrich. The microscopic photograph of the bed composition need to be analyzed and the way to obtain it explained.

(6)   In section 2.3, the 9 parameters are listed above, but there is no indication that those parameters were directly tested. Experimental testing methods and data processing processes need to be specified.

(7)   In Figure 4, the ordinate is not clear. Which is the temperature, pressure and weight?

(8)   I suggest that no references appear in the conclusion.

Please consider the need to resolve the above discrepancies in the revised version.

This paper need been major revision before publication.

That’s all. Thank you.

Date of this review

April 18, 2023

Comments for author File: Comments.pdf

l  General comments:

- Bibliography is enough, actual and relevant;

- English needs revision;

- Subject is interesting and actual.

Author Response

Comment:

l  General comments:

- Bibliography is enough, actual and relevant;

- English needs revision;

- Subject is interesting and actual.

l  Detailled comments:

1. Subject is actual and very interesting. English must be improved. Some sentences are confuse and some spell check is required.

Answer:

Thank you for your valuable comments, which helped us to improve the paper. The text has been corrected with a native speaker in order to eliminate the grammatical and spelling errors.

 

Comment:

2. Please pay more effort to improve the paper so that it addresses the following points sufficiently.

-  added values to previous researches

-  logical connections between sections for chapter 2

Answer:

Thank you for your valuable remarks.  The novelty of the presented research in comparison to previous research was indicated in the abstract as well as the introduction section. We also removed subsections in Chapter 2 to avoid the raised problem.

 

Comment:

3. Abstract should describe the importance of the research and validation method, and key results obtained could be the added values to the knowledge in the subject. If these points are correct, please recorganize and improve the contents to be centralised on this points.

Answer:

Thank you for this valuable comment. The abstract has been supplemented with additional information according to the reviewer’s suggestions.

 

Comment:

4. In figure 1 and 2, not only should the pictures of the experimental system be shown, but also the performance parameters and structural parameters of the test equipment should be illustrated.

Answer:

Thank you for your suggestion. In the paper "Experimental Investigation of an Intensified Heat Transfer Adsorption Bed (IHTAB) Reactor Prototype" (DOI: 10.3390/ma14133520 ) the operating parameters as well as the design parameters of the test equipment have been presented in detail. Nonetheless, according to the Reviewer’s comments, we supplemented this section with the most important information on structural parameters of the test equipment.

 

Comment:

5. In section 2.2, the adsorption bed was composed of silica gel supplied by Sigma-Aldrich. The microscopic photograph of the bed composition need to be analyzed and the way to obtain it explained.

Answer:

Thank you for your valuable remark. Using an Analysette 3 Spartan shaker (FRITSCH GmbH, Idar-Oberstein, Germany), the silica gel was segregated to granulation of 200–250 um. The weight of the silica gel used in the tests was 55 g. The spherical silica gel particles from Sigma Aldrich had an irregular shape with a particle sphericity of 0.65, a density of 2200 kg/m³ and a bulk density of 850 kg/m³. These data are included in section 2.2. 

 

Comment:

6. In section 2.3, the 9 parameters are listed above, but there is no indication that those parameters were directly tested. Experimental testing methods and data processing processes need to be specified.

Answer:

Thank you for your suggestion. Parameters described in section 2.3. were used in the calculations both in this paper and in the previously cited papers. These parameters were necessary to calculate, e.g. minimum fluidization velocity, material porosity and superficial gas velocity.

 

Comment:

7. In Figure 4, the ordinate is not clear. Which is the temperature, pressure and weight?

Answer:

Thank you for your valuable remark. The mass designation error has been corrected in Figure 4 (a-e). In addition, symbol markings have been added to make it easier to read temperature, pressure and weight. We also supplemented the caption of Fig. 4 with the description of the detailed symbols.

 

Comment:

8. I suggest that no references appear in the conclusion.

Please consider the need to resolve the above discrepancies in the revised version.

This paper need been major revision before publication.

Answer:

The references have been removed from the conclusions section according to the reviewer’s valuable suggestion.

The reviewer’s valuable comments and suggestions have been carefully analyzed and the paper was modified according to them.

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

Reviewer 3 Report

The authors carried out the process under low-pressure conditions and to induce fluidization with a pressure difference by adding Al / CNTs in SG. Typical profiles for vapour uptake for different mixtures and the pressure difference were obtained. Some problems should be solved before publication are as following:

1. In keywords, is it “absorption” or “adsorption”? Please check it.

2. When preparing the mixtures containing 5 and 15% of Al or CNTs, how to make the Al or CNTs uniformly mixed with SG? Please make it clear in the text.

3. Why did the addition of 5% Al to the bed had a negative effect on the sorption processes?  Why did the increasing carbon nanotubes content have no longer same effect as that of 5% CNTs? Further analysis and discussions are needed. Please add the corresponding analysis and discussion in the text.

4. Why did you just study the bed pressure difference at a height of 3 and 4 cm？

5. When calculating the pressure difference in Figure 5, the detailed parameters should be given in the text, for example, pressure of gas fluidizing the bed (P0), temperatures (T), average gas velocity in the fluidized bed (Uav) etc..

6. The unit of pressure difference should be included in Figure 5 (a) & (b).

7. The conclusions could be shortened. Focus on the important conclusions.

8. The units of symbols should be included in “List of Symbols and Abbreviations”.

Author Response

Comment:

The authors carried out the process under low-pressure conditions and to induce fluidization with a pressure difference by adding Al / CNTs in SG. Typical profiles for vapour uptake for different mixtures and the pressure difference were obtained. Some problems should be solved before publication are as following:

1. In keywords, is it “absorption” or “adsorption”? Please check it.

Answer:

Thank you for your valuable remark. The keywords have been corrected. Adsorption is correct.

 

Comment:

2. When preparing the mixtures containing 5 and 15% of Al or CNTs, how to make the Al or CNTs uniformly mixed with SG? Please make it clear in the text.

Answer:

Section 2.2 has been supplemented with the below text according to the reviewer’s valuable comment: To prepare the SG-Al and SG-CNT mixtures, the ingredients were measured in the appropriate proportion, then combined and mechanically mixed in three directions. The mixture prepared in this way was poured into the bed column.

 

Comment:

3. Why did the addition of 5% Al to the bed had a negative effect on the sorption processes? Why did the increasing carbon nanotubes content have no longer same effect as that of 5% CNTs? Further analysis and discussions are needed. Please add the corresponding analysis and discussion in the text.

Answer:

Section 3 has been supplemented with the below text according to the reviewer’s valuable comment: The purpose of creating mixtures with aluminum powder and nanotubes was to improve heat transfer coefficients, which was to improve the intensity of sorption processes involving SG, which is the main sorbent in the adsorption bed. Aluminum as a metal does not have sorption capacity, but due to its high thermal conductivity coefficient, it was selected for the tests. However, good thermal properties did not recompensate its lack of sorption capacities.

In the case of CNT, the situation is different. The material itself does not show sorption capacity in the water-CNT pair, but it has such a shape that leads to the creation of a potential difference at the opposite ends of the nanotube, which accelerates the transport of water or steam through the nanotube, thus facilitating the access of water vapour to the sorbent. Probably this phenomenon allowed us to improve the efficiency of sorption processes in the bed.

 

Comment:

4. Why did you just study the bed pressure difference at a height of 3 and 4 cm?

Answer:

Heights of 3 and 4 cm turned out to be the most appropriate heights, as these heights constituted the top of the bed in the stationary state of all the materials tested. Hence, pressure changes at these heights were useful to compare and assess the intensity of the fluidization process of all tested materials. This explanation has be added in section 3.

 

Comment:

5. When calculating the pressure difference in Figure 5, the detailed parameters should be given in the text, for example, pressure of gas fluidizing the bed (P0), temperatures (T), average gas velocity in the fluidized bed (Uav) etc.

Answer:

The temperature of the gas was 25^oC, while the velocity of the gas fluidizing the bed (in this case it was water vapor) was caused by the pressure difference in both chambers.

The minimum fluidization velocity of the solid particles is in the range of 0.43 - 0.68 m/s. The system operated in transient regimes corresponding to bubbling and circulating fluidized beds (superficial gas velocity: 6.6-14 m/s), but the bed did not circulate and was held inside the chamber by the net. According to the Reviewer’s comments, section 2.1 has been supplemented with the above description.

 

Comment:

6. The unit of pressure difference should be included in Figure 5 (a) & (b).

Answer:

Thank you for your valuable remark. The unit of pressure difference is given in Figure 5(a) and (b).

 

Comment:

7. The conclusions could be shortened. Focus on the important conclusions.

Answer:

Thank you for your valuable remark. The "Conclusions" section has been corrected.

 

Comment:

8. The units of symbols should be included in “List of Symbols and Abbreviations”.

Answer:

Thank you for your valuable remark. The units of symbols have been added to the “List of Symbols and Abbreviations”.

 

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

 

 

Reviewer 4 Report

This manuscript has clear ideas and strong readability. Just a few small suggestions: 

1. Please provide the theoretical basis for the experiment, or what mechanism has been revealed through the experiment. Because there are too many options for conducting experiments, including selecting different materials, proportions, sequences, methods, etc., theoretical basis should be provided.

2. The conclusion section includes a total of seven points, which are relatively long and numerous. It is sufficient to directly provide the experimental results or revealed mechanisms in the conclusion section.

Author Response

Comment:

This manuscript has clear ideas and strong readability. Just a few small suggestions:

1. Please provide the theoretical basis for the experiment, or what mechanism has been revealed through the experiment. Because there are too many options for conducting experiments, including selecting different materials, proportions, sequences, methods, etc., theoretical basis should be provided.

 

Answer:

Thank you for your valuable remark. The theoretical basis of the experiment was to induce a fluidization process by differential pressure with an appropriate choice of materials to support the fluidization of adsorption parent material (in this case, silica gel) under low-pressure conditions. Materials used in the tests were selected, taking into account their good thermal properties to enhance heat transfer in the fluidized bed.

According to the Reviewer’s comments, section 2.3 has been supplemented with the above description.

 

Comment:

2. The conclusion section includes a total of seven points, which are relatively long and numerous. It is sufficient to directly provide the experimental results or revealed mechanisms in the conclusion section.

Answer:

Thank you very much for your valuable suggestion. During the analysis of experimental research results, the authors define a lot of important conclusions, which were described in the manuscript. According to the reviewer's comment, the text was re-analyzed and the number of points with final conclusions has been reduced.

 

 

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

 

Round 2

Reviewer 1 Report

I still do not feel the quality of the manuscript is sufficient to meet the required standard of the current journal. The objective, and purpose of carrying out this research have not been mentioned clearly in the introduction. The paper also has some serious English spelling and grammatical mistakes. The results are not discussed in detail. The Figures are also blurred. Finally, in my opinion, the article does not present any advanced achievement to deserve publication.

Author Response

Dear Reviewer,

 

Comment:

I still do not feel the quality of the manuscript is sufficient to meet the required standard of the current journal. The objective, and purpose of carrying out this research have not been mentioned clearly in the introduction.

Response:

Thank you for your comments and suggestions. We supplemented the abstract with the following explanation.

This study aims to analyze the effect of adding Al powder and nanotubes to the adsorption bed mixture on its performance at low-pressure fluidization.

The practical significance of the paper follows from the fact that the obtained results allow for an increase in the performance of the adsorption chillers and, therefore, increase the energy efficiency of the adsorption cooling and desalination systems. Moreover, since adsorption chillers accept low-grade thermal energy sources, including renewable and waste thermal energy, the presented paper contributes to the works on sustainable development. Therefore, the presented results contribute to the zero-emissions concept of the energy processes.

Additionally, we added new keywords: net-zero emission, sustainability, and energy efficiency.

            Finally, we supplemented the Conclusions section with the following statement:

The paper deals with time subjects of high practical significance related to net-zero emission, sustainability, and energy efficiency.

 

Comment:

The paper also has some serious English spelling and grammatical mistakes.

Response:

The text has been corrected in order to eliminate the grammatical and spelling errors.

 

Comment:

The results are not discussed in detail. The Figures are also blurred.

Response:

Thank you for your comments, which allowed us to improve our paper. We improved the discussion of the results by explaining the importance of the pressure difference between the evaporator and the adsorption chamber and the factors responsible for the observed desorption processes. Now the discussion of our results covers the influence of time, pressure, pressure drops, temperature, bed material’s content, the height of the fluidized bed, and the valve state between the evaporator and adsorption chamber.

Additionally, according to the reviewer’s comments, the figures have been substantially corrected.

 

Comment:

Finally, in my opinion, the article does not present any advanced achievement to deserve publication.

Response:

The fluidization in adsorption cooling and desalination systems are new research areas. According to our knowledge, only two research centers deal comprehensively with this issue, i.e. our department at Jan Dlugosz University in Czestochowa and AGH University of Science and Technology. Our paper presents the state of the art of the current research on this cutting-edge and timely subject. According to the reviewers’ comments, due to the lack of other research papers in this area, we emphasized this explanation in the last paragraph of the Introduction section.

Moreover, the results presented in this work show that the adsorption bed composition significantly affects its performance. The study proved that 5% and 15% of Al powder introduced to the bed negatively affect its sorption properties, while the addition of 15% CNTs improves the sorption properties of the bed. This finding is of significant importance in terms of guidelines for the researchers and engineers aiming to develop the adsorption technology dedicated to cooling and desalination applications.

 

 

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have answered the questions pointed out by the reviewer. The reviewer would like to suggest publication of this paper.

Author Response

Dear Reviewer,

 

Comment:

The authors have answered the questions pointed out by the reviewer. The reviewer would like to suggest publication of this paper.

Response:

Thank you for your positive evaluation regarding the publication of our paper.

 

 

Sincerely,

Anna Zylka,

Jan Dlugosz University in Czestochowa, Poland

Faculty of Science and Technology

13/15 Armii Krajowej Ave

42-200 Czestochowa, Poland

e-mail: [email protected]

ORCID: https://orcid.org/0000-0001-6241-0863

 

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

I approve the publication of this paper