Review Reports

Round 1

Reviewer 1 Report

General comment:

The manuscript proposed by the authors is valuable and increase knowledge about new feedstock for biofuels production. This topic is still relatively unrecognized, so every new study makes a major contribution to this area. The subject is in line with a Journal scope in terms of biofuels production. It can be published after major corrections.

32 bulk density? Why hier not solid density (Particle density according to ISO 17225-3 or 7)?

43 please avoid grouping citations. Separate citations and describe specifically what is relevant in the item

47 please avoid grouping citations. Separate citations and describe specifically what is relevant in the item

79 and ash content especially in biomass containing large amounts of bark (see: https://doi.org/10.3390/ en14113016 and https://doi.org/10.3390/en14040818

84 „briquettes have a high calorific value” This statement is misleading to the reader. The briquetting process does not change the energy parameters of biomass - the HHV of the briquette is the same as the HHV of the raw material for its production

105 the source of this classification is needed. 1200kg/m3 is the average, minimum or maximum density?

106 bulk density so low? - „100 to 200 200 kg/m³”

106 higher density results in a higher calorific value (kJ/kg) – This is not true, the densification process does not change the calorific value. The amount of energy in the raw material is the same before and after the densification process. On what principle would this increase in calorific value take place?

107 given definition of BD is imprecise

119 please provide the source of this information

123 from which source are the drawings and do the authors have permission to use them?

138 just as in 105

139 repetition of the incorrect statement from 106

141 from which source are the drawings and do the authors have permission to use them?

174 the drawing is unnecessary and should be removed from the work, especially as it is not in English

180 it should not be a table but a diagram

220 What is the basis for this statement? Several publications on this subject can be found in:  https://doi.org/10.3390/en13081859 or https://doi.org/10.3390/ma14040879

207 – 226 it's more like Introduction

228 8…10% or 8 – 10%?

233-236 on what basis has this been established? Fine particles fill in the spatial structure created by large particles. In the further part of the paper there are results for 8 - 3,15 but also for 8 - 0mm

237-238 „combustion produces more ash because of the quick burning process” not exactly true. The ash content does not depend on the combustion process, it is a parameter that characterises the raw material. The amount of residue produced, which includes ash and unburned material, may depend on the combustion process.

301 what kind of density – specific?

325 briquettes were cut or broken into these lengths?

326 I think that Figure 9a is not necessary

331 why the ash content was not specified?

336 why bulk density? Standards for briquettes require solid density

422 rather HHV

429 the ash content should also be included in this calculation

449 6 or 8mm?

548 calorific value or heating value? It would be better to give values in dry state, so that the results can be compared, with different moisture contents it is difficult to compare

552 which part of the standard 17225?

553 the work should also include a summary table with a comparison to the requirements of the quality standard so that it is clear which parameters have been met and in which class and which have not

 

Author Response

The responses are in the attached file

Author Response File: Author Response.doc

Reviewer 2 Report

The paper is clear, very detailed and well written. All the sections are well structured, figures and pictures have a good resolution and they are useful to understand the work.

For me this paper can be accepted in the present form.

Author Response

The responses are in the attached file.

Author Response File: Author Response.doc

Reviewer 3 Report

1. Table 4 is not clear. I do not underatand what you want to express.

2. Energy consumption of biomass solid fuel production should be considered in this work. If energy consumption is high, the feasibility of the process will be questioned.

3. The logic of the preface is not clear and needs to be combed again. For example, the advantages of biomass solid fuels in bioenergy production should be clarified in the introduction section. What about liquid and gas fuels?
4. What are the advantages of this specialized equipment compared with others?

Author Response

the responses are attached

Author Response File: Author Response.doc

Round 2

Reviewer 1 Report

The article has been improved compared to the previous version and It can be published in present form.