Insights into the High Activity of Hydrotreating Catalysts for Heavy Gas Oil
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsReview for the paper: "Insights into of…"
The paper describes the development of a highly active hydrotreating catalyst for processing heavy gas oil to reduce the nitrogen content to 2 ppm. The catalyst is NiMo/Ɣ-Al2O3 doped phosphate prepared in presence of tartaric acid and polyethylene glycol.
The authors should explain the following issues:
1- It’s unusual to introduce the preparation of the catalyst at the end of the discussion and before the conclusions. In the synthesis of the catalyst, the authors have used phosphoric acid. The question is: which is the value of Ph? The reviewer remembers that at Ph=5 starts to go in solution Al2O3.
Insights into of…
The paper describes the development of a highly active hydrotreating catalyst for processing heavy gas oil to reduce the nitrogen content to 2 ppm. The catalyst is NiMo/Ɣ-Al2O3 doped phosphate prepared in precedence of tartaric acid and polyethylene glycol.
The authors should explain the following questions:
1-It’s unusual to insert the preparation of the catalyst at end of discussion and before the conclusions. In the synthesis of the catalyst, the authors have used phosphoric acid. The question is: which is the value of Ph? The reviewer remembers to the author that at Ph=5 Al2O3 starts to go in solution.
2-In the preparation of the catalyst, you start with Mo with valence 6+ and Ni with valence 2+; what valence Mo and Ni have in the final catalyst?
3-In the section 3.2, the authors write “the catalyst was diluted …of SiC”. Which kind of compound is SiC?
4-At the end, the catalyst is sulfured with CS2, is the final product completely sulfured?
5-If the Mo is completely sulfured, which kind of structure has the MoS2 in the surface of the Al2O3?
6- The sequence of the redox reaction shows the reduction of Mo to 6+ to 4+ from MoO3 to MoS2. Do the elements suffer reduction?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this manuscript, these authors reported fabrication of NiMoP catalyst for converting VGO to be lube base oil, with remarkable N removal. It is useful and interesting. However, the authors need to address the following concerns before the present version can be accepted for publication.
1. In line 156, properties of VGO is listed in Table 1, including S content, N content, and aromatics content. After VGO was hydrotreated with the NiMoP catalyst, N content could be greatly reduced, but no information on the change of S content and aromatics content was provided. Hence, readers would not know whether the hydrotreated VGO could be evaluated to be lube base oil.
2. Experimental details may be improved. What is the water amount in lines 193 and 196? What is the sulfidation time at 140 oC and 230 oC, respectively in line 201? Then in line 202, what is the exact mixture when you say “a mixture of 10% CS2”?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript contains several significant flaws that the authors should carefully address and revise accordingly.
1. The abstract is too general. This should briefly introduce the issues while focusing on specific details about the methodology used. It should also contain significant results with specific numerical data to enhance the credibility and impact of the findings.
2. The results should be compared with those from existing approaches in the literature to ensure they align with expected outcomes. Additionally, more detailed explanations and in-depth analyses are required for improvement.
3. No numeric values are provided to describe your results in sections 2.3 and 2.4. However, I suggest revising this section to enhance its representation and clarity.
4. Results discussion without being supported by other parameters, such as temperature, are merely a series of data with some divagations. The arguments should be supported by temperature and, even, composition at the engine-out. You have temperature info, at least use it properly. Otherwise, it is not meaningful.
5. The research work contains too many old references in the field. So, citing recent articles in the text to support your discussion is necessary, especially the fuel properties. Enhance your text by incorporating insights from articles such as 10.1016/j.meaene.2024.100017.
6. In the methodology section, authors are expected to elucidate the employed research methods in detail.
7. Instead of repeating statements in the conclusion section, I suggest that authors should systematize and point out the most important conclusions or take-home messages from the analysis in summary.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
