Superheated Steam Torrefaction of Biomass Residues with Valorisation of Platform Chemicals Part—2: Economic Assessment and Commercialisation Opportunities

Round 1

Reviewer 1 Report

The article entitled “Superheated Steam Torrefaction of Biomass Residues with Valorisation of Platform Chemicals Part-2: Economic Assessment and Commercialisation Opportunities” is a continuation of an article recent published in Sustainability. The first one presented and ecological assessment and this one presents the economical assessment of a biorefinery proposal still under development stage. The article is well written and its contribution is very clear. 

1- Two things are essential to guarantee the reproducibility of the work:

1.1- The details (as far as possible) and costs of the equipment units. Because only with this information the readers can check if the estimations are consistent or even re-do/adapt the economic assessment with other methodologies. It is not presented in the text and no supplementary material was referenced.

1.2- The mass and energy balances of the biorefinery, for the same reasons. As it was already presented in the first article, I understand that a merely mention to it would be enough.

2- Lines 255-256: “Both investment cost calculations lead to results that differ by less than 5% for the two variants.” Where does it appear? The difference in the Total Investment Cost according to Figure 2 is of more than 100% and in lines 280-281 the authors affirm that the investment costs of the process variant is “significantly higher”.

3- Line 264: “followed by silos”. How? Storage is not shown in Figure 2(b).

4- Figure 3 resolution could be improved.

5- In Table 2, the differences between the specific revenues of the two variants must be clearer: which revenues should be summed to get each one of the reported total revenues?

6- I think the calculations in section 3.4 would be better explained with a concrete example. For instance, how to get the 1123 value for 5-HMF?

7- This reviewer could not see the results explained between lines 399 and 402 in Figure 7(b). Are the variants inverted?

8- Lines 435-438: why these four sectors apply for this particular biorefinery? Is was not explained in the text. The discussion that follows in sections 4.2, 4.4 and 4.5 seems very generic.

Author Response

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Reviewer 2 Report

The scientific concept of the paper is good. This study is interesting to be published; the manuscript adds important information to the existing literature. However, the manuscript needs minor revision, there are some grammar and syntax error.

Author Response

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Reviewer 3 Report

The paper addresses a very interesting and appealing research topic. The structure of the paper is correct. To enhance the quality of this article, some considerations could be evaluated before final acceptance:

• Please check that the meaning of acronyms is defined when they are introduced the first time, both in the abstract and in the manuscript (e.g., SHS is not defined in the manuscript's text).
• Please include, preferably in the first part of the paper, a brief description of the manuscript’s structure.
• Please provide, in figure 1, a legend to identify the meaning of arrows with solid, dashed, and double lines. Moreover, please adopt two different colours (or styles) to distinguish the matters from the energy flows.
• The column “Description/source” in table 1 is quite misleading since “description” and “source” are two different pieces of information. Therefore, the current column should be divided into two columns, one for the “Description” and one for the “Source” of each corresponding parameter. Many references for some costs included in this table are available in the scientific literature (e.g., an estimation of maintenance costs and general expenditure is provided in the research work entitled “An Economic Model to Assess Profitable Scenarios of EAF-Based Steelmaking Plants under Uncertain Conditions”). Please use the existing information in case they are consistent with your research. If no references are identified to certain cost items, a statement as “authors’ assumption” can be shown.
• Section 4 should be rearranged. In my view, a part of the contents included in this section can be moved to the first part of the manuscript. Similarly, a new sub-section (in section 3) could include others contents of the current section 4. In this way, the ‘revised’ structure will be the Results (currently in section 3) followed by “Discussion” (currently in section 5), without any sections between the two parties.
• The conclusion section could include details on the limit and future developments of the research work.

Author Response

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