Demineralization of Miscanthus Biocrude Obtained from Catalytic Hydrothermal Liquefaction: Conditioning through Acid Washing

Round 1

Reviewer 1 Report

I found the paper very interesting and well-organised. I would like only to ask if the authors have investigated what could be the effect of the use of a biocrude produced under different conditions. How does the way to produce it could affect the properties of the sample used by the authors? Please include some information if this is known.

Please explain acronyms the first time they appear in text.

Some references to the environmental impacts of biofuels could be included. I suggest the following: (1) Journal of Cleaner Production, 2017, 157, pp. 254-266; (2) Management of Environmental Quality: An International Journal, 2015, 26(3), pp. 389–406; (3) Bioresource Technology, 2020, 298, 122558.

Author Response

1. I found the paper very interesting and well-organised. I would like only to ask if the authors have investigated what could be the effect of the use of a biocrude produced under different conditions. How does the way to produce it could affect the properties of the sample used by the authors? Please include some information if this is known.

We are pleased to hear that the reviewer finds this paper interesting and well organized. As mentioned in the original manuscript, we only demineralized the Miscanthus HTL biocrude that was produced at 350 °C and 22 MPa. We did not investigate the demineralization of Miscanthus HTL biocrude after producing it in different HTL conditions. Unfortunately, we could not investigate the demineralization of biocrudes produced at different conditions, as the original research did not include the production of samples at different operating conditions. This is however an interesting point for possible future work.

Moreover, we would like to mention that we are also not aware of any other similar investigation in the open-literature. We have indeed highlighted two sources (Ref. 15 and 16 from Steeper energy) which documented the demineralization of HTL biocrudes produced under supercritical conditions (i.e. 400 °C). However, authors of Ref. 15 and 16 did not report the effect of demineralization on the properties of the HTL biocrudes. This already mentioned in the original manuscript. 

2. Please explain acronyms the first time they appear in text.

In revised manuscript, we addressed the reviewer comment (i.e. explanation of acronyms) in line 32, line 33 and line 44.

3. Some references to the environmental impacts of biofuels could be included. I suggest the following: (1) Journal of Cleaner Production, 2017, 157, pp. 254-266; (2) Management of Environmental Quality: An International Journal, 2015, 26(3), pp. 389–406; (3) Bioresource Technology, 2020, 298, 122558.

We thank the reviewer for suggesting some of the references. We found reference 3 (Bioresource Technology, 2020, 298, 122558) suitable and compatible with our study and therefore, we have incorporated this reference in the revised manuscript (Ref. 24 in our main text).

Reviewer 2 Report

Dear Authors

 

the work is interesting, well presented and clearly described in a good English form.

I recomend pubblishing in the present form

Reviewer 3 Report

Review

Title: Demineralization of Miscanthus biocrude obtained from catalytic hydrothermal liquefaction: Conditioning through acid washing

 

Hydrothermal  liquefaction  (HTL)  it is undoubtedly is an interesting  technology  to  produce  a  liquid  biofuel from a wet biomass so without the need of the energy consuming drying process.

However the title of this manuscript is quite often described by scientists and very popular hence I have doubts about the novelty aspect.

First of all, it is necessary to show what is novelity.

The references should contain more recent literature from 2019 and 2020. There are many current publications on this issue.

It is also necessary to supplement the discussion of the results with literature references comparing the results obtained by other researchers.

Paragraph 225 - Table 4 no reference to the calculations. On the basis of what formulas were these data calculated.

Maybe it would be worth calculating e.g. energy recovery.

These remarks lead me to propose major revision.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

I accept the corrections after the review