Biomass Pellet Processing from Sugar Industry Byproducts: A Study on Pelletizing Behavior and Energy Usage

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

The topic of the work is interesting and current. I have a couple of suggestions and remarks.

Shorten the introductory part. Focus on important things and be concise.

When you did the proximate and ultimate analysis, why didn't you determine the content of lignin, cellulose and hemicellulose? Table 1.

About picture 2. The picture under a, b and c seem a little unclear.

Paragraph 2.3.2 why you did not determine the mechanical strength and hardness. Or you think that these parameters are irrelevant for you pellet.

In Figure 8. No key differences can be seen except for the arrangement of the pellet pieces.

In Figure 9. Why does the PMD sample bounce off the others?

You have shown a lot of results, but they seem a bit rushed.

Your work is too long, perhaps you could have transferred some results to additional material.

Author Response

Dear Respected Reviewer,

We appreciate your interest in the study "Biomass Pellet Processing from Sugar Industry Byproducts: A Study on Pelletizing Behavior and Energy Usage" as well as your insightful recommendations and criticism that have helped us to refine our work. We would like to clarify the following further in response to your concerns, and we have made the necessary modifications in accordance with the recommendations.

Please see the attachment.

Yours sincerely,
 
Mr.Pasawat Sanchumpu
PhD student. Agricultural Engineering, Faculty of Engineering, Khon Kaen University.
E-mail: pasawat.s@kkumail.com

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

33: are energy improvements actually increasing energy demand?

34-38:  The percentages are inconsistent with each other, and there is no clear basis (percent of what)

39-40: sentence wording is off

46: consider paragraph change at “agricultural waste”

47-48: unclear what this sentence means

49: This sentence really does not tell us anything

50: producing biomass absorbs energy, producing biomass energy usually releases them (unless BECCS is used)

53-54: biomass does not store “carbon dioxide in the atmosphere”, it stores carbon in biomass on the land

57-58: use of “another” is incorrect

100-104: as stated these statements are inconsistent, as power plants don’t have enough fuel, but abandoned 30+ MMtonne.  Also, dry tons? Wet tons? 

104-106: unit consistency

120-126: This statement would be useful much earlier, to clarify the why of the goal

127: fig. 1: provide a tonne or kg / hectare for the portion that goes to the sugar factory as well

130: just from academics?  The US has installed over 10MM tonne/year of capacity in the past 15 years I believe

133:  limited literature but significant interest?  Please be consistent

136-150:  generally, these sentences need improved wording

158:  There is a lot of results in the materials and methods section.  I recommend re-ordering the presentation to separate materials and methods from results.

164-167: please give the sugar mill this came from, and ideally the processing steps that lead to your raw materials.

170-172: wording

175: principle of machining is not a term of art I am familiar with.  Is “cutting” meant?

173-175:  If available give model and manufacturer for the machine

176-177:  If available give model and manufacturer for the machine (thank you for giving screen size and RPM)

177: what kind of hammer mill (e.g. fixed or swing hammer), was it air assisted?

182-190: good description, please include manufacturer and model, or if custom built, a diagram,

191: Reference to figure 2 is incorrect

192:  for future reference, biomass is generally dried to constant weight, as 24 hours is frequently insufficient to reach equilibrium (see ISO 18134)

200: container geometry?  Size / shape can matter.  Was this done on a wet or dry basis?

222-223: wording

224:  SCL is not defined (is this SCB?).  This is then repeated several more times.

 

223-227: recommend not listing values, just reference the table

238: state pelletizer manufacturer and model

244-245: meaning of this sentence is unclear

265-267: unclear what is meant

267-269: unclear what is meant

263-275: no need to list proportions, reference the table

277-278: I don’t think these papers indicated quantities, but a method.  Please make clear

302-305: container volume and scale precision?

329: Diametric does not seem to be the right word here

331-332: This method is for rock samples, so may or may not be appropriate.  Were curved platens used to reduce early cracking?

350-352: FVI seems to reference “fuelwood value index” which may or may not be appropriate for comparison. This only seems to appear once, and is presented in a way that is unclear and has no external comparisons.  Please either more clearly explain this, or leave it out.

361: “Video Recording equipment (multimeter) “ does not make sense.  Please provide details of the power measuring system.  From personal experience, time scale matters a lot (especially if this is instantaneous measurements not averages).   Small Pelletizers and hammer mills tend to have very noisy power consumptions numbers

373-380: Unclear on this method. At very least, wording / explanation needs improvement.

383-388: wording is off

388: “optimal diameter” of what?  The pellet die hole (these are commonly 3-8 mm depending on application)

390: unclear what is meant by “force” and “friction” in this context

392: does this power consumption include heating energy (I assume yes from the values)?  If so, would any industrial producer use electricity to heat a dryer?  What other sources of thermal energy might be applied?

393-395: this sentence does not make much sense, and does not belong here.

398: inaction?

400: is crushed the right word

402: this sentence is unclear

414-415: sentence structure

417-419: this sentence belongs earlier when discussing individual materials not mixes

424-426: this does not seem correct, and disagrees with statements made earlier in this paragraph

426-428: these sentences seem to contradict each other

443:  This section has a great deal of material having to do with moisture content

444: is the moistures content critical or is “figuring it out” critical?

445-447: wording unclear

448: percentages in this line have no clear connection to the surrounding material

Pg. 13: This entire page is almost unreadable.  Some breakup of this is needed.  The statements made are mostly restating data in tables, and quite a few sentences are incomplete, unclear, or internally inconsistent.  Many statements are internally inconsistent, or incorrect.

500: Moisture rating concept appears with no explanation.  Table 6 is unclear on meaning, and the letter to number concept is entirely unexplained.

503: data for at least one outcome suggest moistures below 15% (10-12% is common in wood pelletizing) would be better, so this statement may be a stretch.

508-509: this statement does not seem to be based on, or referring to anything in the data.  Please clarify.

513: no “significant at 5% level” markings are shown, why is this included.

515: “same letter” statement does not seem to mean anything.  Clarify.

520: what SEC is meant here?  Just pelletization?  Milling? 

520,521: Are there only 3 data points in the a,b,c plots?  If so, just make them bar charts.  These are misleading

530: this sentence makes no sense

531-533: this sentence is very confusing.  Also, why 300 seconds,

534-536: This consistent power consumption seems unlikely, as small pelletizers tend to have very volatile energy consumption.  I am concerned you method (which was not explained) is missing something here.

537: compression pressure?  Adjusted how?

541-542: the meaning here is unclear

542-543: this sentence is unclear

545-554: none of this discussion makes sense,

565: The energy consumptions do not seem to match the average amps.  No explanation of how these connect is provided.

Did not continue reviewing past this point. 

Comments on the Quality of English Language

See general notes.

Author Response

Dear Respected Reviewer, 
Thank you for your interest in the research "Biomass Pellet Processing from Sugar Industry Byproducts: A Study on Pelletizing Behavior and Energy Usage" and for your valuable suggestions and comments to improve our research. We have made the corrections according to your recommendations (the text highlights will be blue) and would like to further clarify your concerns as per the attached documents.

Please see the attachment.

Yours sincerely,
 
Mr.Pasawat Sanchumpu
PhD student. Agricultural Engineering, Faculty of Engineering, Khon Kaen University.
E-mail: pasawat.s@kkumail.com

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The present study focused on using waste materials from the sugar industry,  such as sugarcane straw, bagasse, and filter cake, to compress into pellets to investigate pelletizing 19 behavior and energy usage. Some issues should be adressed:

 

(1) Page 8, some unnecessary blank lines existes, Line 300 and 306, for example;

(2) Page 16, Line 551-552, "The biomass pelletizing pressure also rose as the size of the biomass particles increased; the biomass particle size with the smallest size also had the greatest size and the lowest pelletizing pressure", some more detailed discussion is suggested to be added;

(3) Page 20, "the biomass pellet's weight will increase 651 proportionately with the powder's volume.", some more deeper explanations are suggested to be added;

 

Overall, the paper is well organised and can be accepted after minor reversion.

Author Response

Dear Honored Reviewer,   Thank you for your interest in the study "Biomass Pellet Processing from Sugar Industry Byproducts: A Study on Pelletizing Behavior and Energy Usage" and for your helpful thoughts and comments to improve our research. We have made modifications as instructed (the text highlights will be yellow) and would like to further explain the questions as per the attached documents.   Please see the attachment.   Yours sincerely,   Mr.Pasawat Sanchumpu PhD student. Agricultural Engineering, Faculty of Engineering, Khon Kaen University. E-mail: pasawat.s@kkumail.com

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

My main concern is that the dataset in figure 10 seems to contain data that has been manipulated / synthetically generated, not collected from an operating pellet mill.  As an example, below is the plot of figure 10.a, with repeated artifacts highlighted.  I strongly recommend that the source data be reviewed, and provided in a Supplementary Material document.  Data should ideally include startup, warm up, and clearing of the press at the end of the run, and an indication of the portion of the dataset used for the stated measurements.  Any manipulation / modification of the data (e.g. subtracting out no-load pellet mill power) should be discussed.

 

Comments on the Quality of English Language

Considerable improvements in the written English in this paper are still needed.

Author Response

Dear Respected Reviewer,

    We sincerely apologize for any concerns our explanation may have caused and appreciate your recognition of the importance of the graph in Figure 10. We also extend our gratitude for your valuable suggestions and feedback, which are crucial for improving our research. To address your concerns further, we have provided additional explanations in the attached document.

Once again, we appreciate the Reviewer's time in reading our work and offering suggestions for how to make this article greater. We expect that our responses will contribute to a clearer understanding of the research.

Yours sincerely,

 

Mr. Pasawat Sanchumpu

PhD student. Agricultural Engineering, Faculty of Engineering, Khon Kaen University.

E-mail: pasawat.s@kkumail.com

Author Response File: Author Response.pdf