Hydroprocessing of Gasoline on Modified Alumina Catalysts

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Any catalytic process that increases the octane rating of gasoline or that leads to the reduction of sulfur in products derived from petroleum processing is interesting. However, despite the results obtained in this research, how the results are shown is insufficient. Some aspects must be improved and others included, which are the following. 

1. Describe the method of synthesis of the catalysts, this includes mentioning the salts of Ni, Co, Mo, W and La used, the proportion of the oxides of these metals in the prepared catalysts, as well as the phosphorus content and the type of used aluminum hydroxide (gibbsite, bayerite, nordstrandite or doyleite).

2. Show the results (tables, figures, graphs) of the techniques used to confirm the presence of the CoO, MoO₃, Al₂O₃, WO₃, and NiO phases, as well as the analysis conditions, the model and the name of the instrument used.

3. Describe the instrument used to measure the content of alkanes, isoalkanes, alkenes, etc., in the reaction products. This includes the model and name of the instrument.

4. Discuss, based on the results of the characterization of the solids, their catalytic activity, since the measurement of their basicity is insufficient to explain the results.

5. The procedure for ammonia desorption studies is not described. The specifications of the equipment are not described either.

6. Reference 18 does not describe how the specific surface area measurement analyzes were carried out by the BET method. The procedure used in the ammonia desorption studies is also not described. Additionally, this article does not analyze or make any mention of the specific surface area of the materials used.

7. Specify which technique is XPA (line 170) since it appears that it was used in conjunction with TEM to identify the chemical species present on the surface of the catalysts. Species are normally identified by XRD and in many cases by HRTEM if the interplanar distances presented by the different elements or chemical compounds are known.

8. Improve the entire discussion of results.

9. Increase the number of references

Author Response

Response to Reviewer 1 Comments

 

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

 

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Must be improved	Improved.
Are all the cited references relevant to the research?	Must be improved	Improved.
Is the research design appropriate?	Must be improved	Improved.
Are the methods adequately described?	Must be improved	Improved.
Are the results clearly presented?	Must be improved	Improved.
Are the conclusions supported by the results?	Must be improved	Improved.

3. Point-by-point response to Comments and Suggestions for Authors

 

1. Describe the method of synthesis of the catalysts, this includes mentioning the salts of Ni, Co, Mo, W and La used, the proportion of the oxides of these metals in the prepared catalysts, as well as the phosphorus content and the type of used aluminum hydroxide (gibbsite, bayerite, nordstrandite or doyleite).

 

Response 1: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The synthesis of catalysts is carried out as follows. The catalysts were prepared by simultaneous impregnation of a mixture of peptized aluminum hydroxide with zeolites HZSM-5 and HY, water-soluble salts of nickel, cobalt, molybdenum, tungsten and lanthanum: Ni(NO₃)₂×6H₂O, Co(NO₃)₃×6H₂O, (NH₄)₆Мо₇О₂₄×4H₂O, (NH₄)₁₀W₁₂О₄₁×5H₂O, La (NO₃)₃×6H₂O, as well as phosphoric acid and with the introduction of modifying additives. The type of aluminum hydroxide used is pseudoboehmite.”

 

2. Show the results (tables, figures, graphs) of the techniques used to confirm the presence of the CoO, MoO₃, Al₂O₃, WO₃, and NiO phases, as well as the analysis conditions, the model and the name of the instrument used.

 

Response 2: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“To confirm the presence of the phases the method of electron microscopy was used on a transmission electron microscope “EM-125K”, U = 75 kV, using electron microdiffraction. Samples were prepared using the carbon replica method. The shape and size of zeolite particles were determined using a SEMLEO-420 electron microscope with a resolution of 15 A at a magnification of 1000 to 5000. In a number of cases, the synthesized products were characterized using crystalloptic analysis (MIN-8 optical microscope). Microdiffraction images were interpreted using standard ASTM tables.”

 

3. Describe the instrument used to measure the content of alkanes, isoalkanes, alkenes, etc., in the reaction products. This includes the model and name of the instrument.

 

Response 3: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The hydrocarbon reaction products were analyzed by gas chromatography using a Chromatek-Kristall chromatograph with a katharometer and a flame ionization detector. The chromatograph calculates the fractional composition automatically. For the analysis of hydrocarbons, a glass column 3 m long, 4 mm in diameter, filled with g-Al₂O₃ was used. For the analysis of oxygen-containing compounds a similar column with 15% PEG-300/PS-1 was used. Carrier gas (argon) rate was 30 ml/min, hydrogen rate was 40 ml/min, air speed was 400 ml/min. The detector temperature was 443 K, evaporator temperature was 443 K, the column temperature was 403 K.”

 

4. Discuss, based on the results of the characterization of the solids, their catalytic activity, since the measurement of their basicity is insufficient to explain the results.

 

Response 4: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The physico-chemical characteristics of the catalysts were studied using Brunauer-Emmett-Teller (BET) surface area analysis, electron microscopy and temperature-programmed desorption of ammonia methods.”

 

5. The procedure for ammonia desorption studies is not described. The specifications of the equipment are not described either.

 

Response 5: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The ammonia temperature-programmed desorption method was used to determine the numbers and strengths of centers of catalysts capable of interacting with specific molecules. Desorption was carried out on a USGA-101 device. To calculate the activation energy values, ammonia was desorption from the samples at different linear heating rates - 5, 10, 15 and 20 deg/min. To carry out the analysis, the sample was preliminarily saturated with the analyte, loosely bound molecules were stripped off, and then linear heating was started in a flow of inert gas.”

 

6. Reference 18 does not describe how the specific surface area measurement analyzes were carried out by the BET method. The procedure used in the ammonia desorption studies is also not described. Additionally, this article does not analyze or make any mention of the specific surface area of the materials used.

 

Response 6: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The combination of electron crystallography (EMV-100AK electron microscope) and X-ray diffraction (DRON-0.5 diffractometer) was used to determine the structure of obtained catalysts. Identification of obtained images was provided via ICDD (International Center for Diffraction Data).

According to the Brunauer-Emmett-Teller (BET) surface area analysis method, the surface area of the synthesized catalysts ranges from 211 to 274 m²/g with pore size diameter 4-10 nm and total pore volume that does not exceed 0.28-0.41 cm³/g.”

 

7. Specify which technique is XPA (line 170) since it appears that it was used in conjunction with TEM to identify the chemical species present on the surface of the catalysts. Species are normally identified by XRD and in many cases by HRTEM if the interplanar distances presented by the different elements or chemical compounds are known.

 

Response 7: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“To identify the chemicals present on the surface of the catalysts, the method of electron microscopy was used on a transmission electron microscope “EM-125K”, U = 75 kV, using electron microdiffraction. Samples were prepared using the carbon replica method. The shape and size of zeolite particles were determined using a SEMLEO-420 electron microscope with a resolution of 15 A at a magnification of 1000 to 5000. In a number of cases, the synthesized products were characterized using crystalloptic analysis (MIN-8 optical microscope). Microdiffraction images were interpreted using standard ASTM tables.

The combination of electron crystallography (EMV-100AK electron microscope) and X-ray diffraction (DRON-0.5 diffractometer) was used to determine the structure of obtained catalysts. Identification of obtained images was provided via ICDD (International Center for Diffraction Data).”

 

8. Improve the entire discussion of results.

 

Response 8: Thank you for pointing this out. We agree with this comment. Additions to the content of the article manuscript regarding research methods and discussion results are highlighted in green.

 

9. Increase the number of references

 

Response 9: Thank you for pointing this out. We agree with this comment. 6 new literary sources have been added to the list of references, which are highlighted in green.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

My comments are in the attached file.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

  English usage throughout manuscript requires of profound revision.

Author Response

Response to Reviewer 2 Comments

 

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

 

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Must be improved	Improved.
Are all the cited references relevant to the research?	Must be improved	Improved.
Is the research design appropriate?	Must be improved	Improved.
Are the methods adequately described?	Must be improved	Improved.
Are the results clearly presented?	Must be improved	Improved.
Are the conclusions supported by the results?	Must be improved	Improved.

3. Point-by-point response to Comments and Suggestions for Authors

 

1. English usage throughout manuscript requires of profound revision.

 

Response 1: To improve the writing of the manuscript in English, we will use the services of the English Editing Department.

 

2. What is the meaning of “catalysate”?

 

Response 2: During hydroprocessing, straight-run gasoline fractions produce a catalyzate, a component of high-octane gasoline, and aromatic hydrocarbons.

 

3. “various silicate modules”. Ditto as in 2.

 

Response 3: Silicate module is the molar ratio of SiO₂ and Al₂O₃.

 

4. “According to the dependencies shown in Figures 2 and 3, changes in the sulfur content in gasoline, caused by an increase in temperature in the hydrotreating reaction, and the octane number increases.” Commonplace!!!

 

Response 3: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“In this work, cheaper platinum-free catalysts have been developed in the process of converting low-octane gasoline into high-octane fuel. The process takes place under less severe conditions than the industrial reforming process where platinum-containing systems are used as catalysts. During hydrotreating on industrial catalysts, the octane number does not increase, only the sulfur content decreases. On the catalysts we have developed, the process of hydrotreating and hydroisomerization occurs simultaneously; as a result of these reactions, low-sulfur and high-octane gasolines are obtained.”

 

5. “It is noted that the amount of sulfur found in the final sample decreases with increasing temperature. In general, this tendency”. Ditto as in 4.

 

Response 5: An increase in temperature accelerates the hydrotreating reactions; naturally, the sulfur content at high temperatures is less than at low temperatures in the hydrotreating process.

 

6. “the content of substances in the catalyst”. Substances?

 

Response 6: This refers to the material or component composition of the catalyst. In this study, new catalysts based on zeolites with the introduction of modifying additives: nickel, cobalt, molybdenum, tungsten, a rare earth element (lanthanum), and phosphorus were obtained and tested in the process of catalytic hydrotreating of straight-run gasoline.

 

7. Section regarding acidity analyses by ammonia TPD must be rewritten. Impossible to get the idea authors try to convey.

 

Response 7: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“To establish the acid-base characteristics of the catalysts, the method of temperature-programmed ammonia desorption was used (Table 1). Ammonia adsorption on the surface of catalysts occurs in two forms. The composition of acid centers may include metals in various degrees of oxidation, fixed both inside the zeolite cavities and on their outer side. The functioning of various types of centers in catalytic processes is often considered as independent, without taking into account the possibility of their joint action on the reactant molecule. However, it can be assumed that it is their simultaneous presence that ensures the polyfunctionality of the catalytic system.”

 

8. Pics in Fig. 4 are of EXTREMELY bad quality!

 

Response 8: Upon re-analysis, the photographs turned out to be the same as in the manuscript of the article.

 

9. The data of the TEM and XPA studies”. XPA?

 

Response 9: An error was made here: corrected to the X-ray diffraction (XRD) method. Corrections have been made to the sentence in the text of the manuscript.

 

10. “On the surface of the catalyst CoO-WO3-La-P-HZSM-HY-Al2O3 (Figure 4b) structures were found, the size of which ranges from d ≈ 2.5-3.0 nm, consisting of La2O3. How materials composition was determined?

 

Response 10: The manuscript of the article is supplemented with the following text.

“The combination of electron crystallography (EMV-100AK electron microscope) and X-ray diffraction (DRON-0.5 diffractometer) was used to determine the structure of obtained catalysts. Identification of obtained images was provided via ICDD (International Center for Diffraction Data).”

 

11. “There are clusters with d ≈ 5.0 and 20.0 nm of highly dispersed particles (d ≈ 0.20-0.25 nm) consisting of La4W9O33 and WO3. In addition, there are areas with small clusters of dense particles with d ≈ 5.0-7.0 nm, the microdiffraction pattern of which can be attributed to LaO2, CoSi,”. EXPERIMENTAL EVIDENCE???

 

Response 11: The manuscript of the article is supplemented with the following text.

“To identify the chemicals present on the surface of the catalysts, the method of electron microscopy was used on a transmission electron microscope “EM-125K”, U = 75 kV, using electron microdiffraction. The combination of electron crystallography (EMV-100AK electron microscope) and X-ray diffraction (DRON-0.5 diffractometer) was used to determine the structure of obtained catalysts. Identification of obtained images was provided via ICDD (International Center for Diffraction Data).”

 

12. “the microdiffraction patterns”. Which ones?

 

Response 12: The figures show the corresponding microdiffractions.

 

13. “with a new composition”. ??

 

Response 13: In this study, new modified zeolite-based catalysts were prepared.

 

14. “A mixture of aluminum hydroxide with zeolites HZSM-5 and HY, water-soluble salts of nickel, cobalt, molybdenum, tungsten, rare-earth element-lanthanum, phosphoric acid were used for catalysts preparation”. Details, technique used, etc.???

 

Response 14: Thank you for pointing this out. We agree with this comment. The manuscript of the article is supplemented with the following text.

“The synthesis of catalysts is carried out as follows. The catalysts were prepared by simultaneous impregnation of a mixture of peptized aluminum hydroxide with zeolites HZSM-5 and HY, water-soluble salts of nickel, cobalt, molybdenum, tungsten and lanthanum: Ni(NO₃)₂×6H₂O, Co(NO₃)₃×6H₂O, (NH₄)₆Мо₇О₂₄×4H₂O, (NH₄)₁₀W₁₂О₄₁×5H₂O, La (NO₃)₃×6H₂O, as well as phosphoric acid and with the introduction of modifying additives. The type of aluminum hydroxide used is pseudoboehmite.”

 

15. “The preparation process of the described catalyst is typical for the same type of catalyst, which allows to prepare sufficiently large batches of modified zeolite- containing catalysts and offer them for industrial applications” Absolute non-sense!!!

 

Response 15: The results of the study allow us to make an assumption about the expediency of using the new studied catalysts in the process of catalytic hydrotreatment under industrial conditions. Previously, similarly synthesized catalysts have already been tested in production conditions and have shown high activity.

 

16. “straight-line gasoline”. ??

 

Response 16: Straight-run gasoline is gasoline (light gasoline fraction) obtained from crude oil and having a temperature of boiling of 180-200°C.

 

17. “analysis of the results of electron microscopy shows that these catalysts are “characterized by the simultaneous presence of acidic (Brensted and Lewis), M0 or Мn+ metal and mixed centers.” Acidity determination by electron microscopy?? Beyond absurdity!!!

 

Response 17: A mistake was made here: using TEM, XRD and temperature-programmed desorption of ammonia. Corrections have been made to the sentence in the text of the manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors made most of the corrections, which shows their commitment to the research.

Because it was evident through iThenticate that there is a lot of similarity with the article "Development and Testing of Modified Alumina Catalysts for Hydrotreating Petroleum Gasoline Fraction" it is recommended to make changes to the Abstract of the article, which is the section in which this situation is presented.

Author Response

Response to Reviewer 1 Comments after Round 2

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

 

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Yes
Are all the cited references relevant to the research?	Yes
Is the research design appropriate?	Yes
Are the methods adequately described?	Yes
Are the results clearly presented?	Yes
Are the conclusions supported by the results?	Yes

3. Point-by-point response to Comments and Suggestions for Authors

 

1. The authors made most of the corrections, which shows their commitment to the research.

Because it was evident through iThenticate that there is a lot of similarity with the article "Development and Testing of Modified Alumina Catalysts for Hydrotreating Petroleum Gasoline Fraction" it is recommended to make changes to the Abstract of the article, which is the section in which this situation is presented.

 

Response 1:

Thank you for pointing this out. We agree with this comment. The abstract of the manuscript has been amended and is presented as follows.

“The growing demand for motor fuels with a simultaneous decrease in light oil reserves stimulates the involvement of high-sulfur crude raw material in the processing. The creation of catalysts with improved catalytic properties for the production of high-octane fuels and low sulfur content is relevant for the petrochemical industry. In this report, new catalytic systems based on zeolites modified with lanthanum and phosphorus for the hydrotreating of straight-run gasoline have been synthesized and tested. During the hydrotreating process of straight-run gasoline in the presence of synthesized catalysts, it was found that the highest octane number (88.6) was obtained on NiO-MoO₃-La-P-HZSM-HY-Al₂O₃ (K-3), the sulfur content decreased from 0.0088% to 0.001%. Tests of the CoO-WO₃-La-P-HZSM-HY-Al₂O₃ (K-2) catalyst showed that the minimum sulfur content in the gasoline hydrotreating product was 0.0005%, which is significantly lower than for other catalytic systems. These indicators of sulfur content in sulfur hydrotreating products fully meet the Euro-5 standard. Thus, the catalysts synthesized in this work can be recommended for the process of hydrotreating gasoline fractions to produce high-octane fuel with a low sulfur content that meets international quality standards.”

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper has been improved but is still not ready for publication. For instance, what is the effect of La (basic additive) on properties of sulfided catalysts? See, for example:

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content. Catalysts 2019, 9(4),  359; https://doi.org/10.3390/catal9040359

Thiophene HDS on La-Modified CoMo/Al2O3 Sulfided Catalysts. Effect of Rare-Earth Content. Top Catal 63, 529–545 (2020). https://doi.org/10.1007/s11244-020-01326-8

Comments on the Quality of English Language

 Extensive editing of English language required.

Author Response

Response to Reviewer 2 Comments after Round 2

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

 

2. Questions for General Evaluation	Reviewer’s Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Must be improved	Improved.
Are all the cited references relevant to the research?	Must be improved	Improved.
Is the research design appropriate?	Can be improved	Improved.
Are the methods adequately described?	Must be improved	Improved.
Are the results clearly presented?	Must be improved	Improved.
Are the conclusions supported by the results?	Must be improved	Improved.

3. Point-by-point response to Comments and Suggestions for Authors

 

1. The paper has been improved but is still not ready for publication. For instance, what is the effect of La (basic additive) on properties of sulfided catalysts? See, for example:

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content. Catalysts 2019, 9(4),  359; https://doi.org/10.3390/catal9040359

Thiophene HDS on La-Modified CoMo/Al2O3 Sulfided Catalysts. Effect of Rare-Earth Content. Top Catal 63, 529–545 (2020). https://doi.org/10.1007/s11244-020-01326-8

 

Response 1: Thank you for pointing this out. To explain the effect of lanthanum on properties of sulfided catalysts, section “2. Results and discussion” is supplemented with the following sentences citing new literature 24-26, which are highlighted in yellow.

 

“Environmentally friendly lanthanum is a low-cost rare earth element that has been added to catalysts and supports to improve their thermal stability and surface basicity. For example, reducing the acidity of aluminum oxides by 60% contributed to increasing the stability of ethanol conversion by reducing coke formation. The higher stability of La-modified HZSM-5 catalysts during the decomposition of methyl mercaptan compared to the undoped material was due to lower Brønsted acidity [24, 25].

It was shown in [26] that modifying a Ni-Mo hydrotreating catalyst with rare earth elements Ce and La allows increasing the stability of operation. Lanthanum is a better activity stabilizer than cerium, and also increases the hydrodesulfurization activity of the Ni-Mo catalyst by 5-10%.

Modification of zeolite with rare earth elements leads to a redistribution of its acid sites in strength and the formation of new active centers, which include modifier elements. Changing the ratio of acid sites of modified zeolites affects their catalytic properties in the process of natural gas conversion. To obtain an effective catalyst for the conversion of gasoline into aromatic hydrocarbons, a certain combination of weak and strong acid sites is required in the catalyst, which is achieved by regulating the amount of modifiers in the catalytic system.”

 

2. Extensive editing of English language required.

 

Response 2: To improve the writing of the manuscript in English, we will use the services of the English Editing Department.

Author Response File: Author Response.pdf