Thermal Cracking Furnace Optimal Modeling Based on Enriched Kumar Model by Free-Radical Reactions
Round 1
Reviewer 1 Report
Comments on Manuscript processes-665290:
The authors discuss their improved kinetic model for thermal cracking, which is going to extend the adaptability to various feedstocks. Personally, I am in favor of publication of such investigations. Frankly speaking, however, the improvement claimed is not well-demonstrated to me. The authors should explicitly highlight how the manuscript is filling the existing knowledge gap in the field of thermal cracking, which is flooded with similar reports; how the research conducted advances the Science in related fields, i.e., process modeling; the discussion part should be improved. Although some interesting data have been presented, the draft is not suitable for publication in Processes in its present form. The term “ethylene cracking furnace” is not correct here, as the furnace does not crack ethylene as the main role. Moreover, liquid feedstocks do not produce ethylene as the main product. Hence, the authors must replace the inappropriate term with “cracking furnace” or “thermal cracking furnace”. Lines 55–57: I am not convinced that the Kumar–Kunzru model is a cornerstone for modeling of the thermal cracking kinetics of heavy feedstocks. I think the authors have overestimated the model, and their sentence inappropriately refers to “heavy feedstocks”, while naphtha is not considered heavy. There exist many more powerful models in the literature. Discuss the shortcoming of the existing techniques and also highlight how the current work is overcoming the listed limitation. Clearly describe your objectives and why it is required to run this study. While the manuscript addresses the cracking furnace, the role of the rate of heat transfer to and inside the reactor should be still clarified. Without such information, the conclusions and comparisons are tentative. Numerous reports are available in the public domain, the missing ones of which should be included in the citations [please find them in the next comments]. Moreover, many of the findings were discussed vaguely and not presented in a critical format. The authors claim the introduction of an improved kinetic model, but the improvement made is not clear and convincing enough. Several relevant papers on the kinetics of thermal/catalytic cracking of hydrocarbons are missing. All of them should be cited in the manuscript [1-17]. Please define all abbreviations at their first appearance. For instance, please see “K-R structure…”, “EB”, etc. Title: some words are capitalized and some are not. Please write then consistently. Line 34: “The work of modeling a furnace can be mainly divided into two parts, the reaction modeling and the reactor modeling.” This statement is not correct. A process furnace consists of several other parts as well, including external heat transfer models. Please revise accordingly. Lines 84, 85: “The core idea of K-R (Enriched Kumar model with free-radical approach) is enriching the Kumar model with free-radical approach”. Is the core idea really new? We all know that molecular models are only simplified schemes for certain reaction systems within their constraints. More sensitivity analysis is required for model validation and supporting the key conclusions. What is the role of steam in the reaction kinetics? Figures: the quality is not adequate. Please improve all figures. The language of the paper is really poor and, therefore, another serious round of editing is required. For instance, please correct “predict product yield” to “predicted product yield” and “…and with high accuracy” to “…with high accuracy”. Please also make a thorough grammar check. For instance, you may refer to “Ethylene is an important olefinic hydrocarbons…” or “showed” on Line 109. Please also avoid conversational tone, e.g., “can’t”.
References:
[1] D.L. Allara, R. Shaw, A Compilation of Kinetic Parameters for the Thermal Degradation of n-Alkane Molecules, J. Phys. Chem. Ref. Data, 9 (1980) 523–557.
[2] M. Ghashghaee, S. Shirvani, Two-step thermal cracking of an extra-heavy fuel oil: experimental evaluation, characterization, and kinetics, Ind. Eng. Chem. Res., 57 (2018) 7421–7430.
[3] M. Dente, S. Pierucci, E. Ranzi, G. Bussani, New Improvements in Modeling Kinetic Schemes for Hydrocarbons Pyrolysis Reactors, Chem. Eng. Sci., 47 (1992) 2629–2634.
[4] L. Szepesy, Feedstock Characterization and Prediction of Product Yields for Industrial Naphtha Crackers on the Basis of Laboratory and Bench-Scale Pyrolysis J. Anal. Appl. Pyrol., 1 (1980) 243–268.
[5] M. Ghashghaee, R. Karimzadeh, Multivariable optimization of thermal cracking severity, Chem. Eng. Res. Des., 89 (2011) 1067–1077.
[6] E. Joo, S. Park, M. Lee, Pyrolysis Reaction Mechanism for Industrial Naphtha Cracking Furnaces, Ind. Eng. Chem. Res., 40 (2001) 2409–2415.
[7] M. Ghashghaee, S. Shirvani, S. Kegnæs, Steam catalytic cracking of fuel oil over a novel composite nanocatalyst: Characterization, kinetics and comparative perspective, J. Anal. Appl. Pyrol., 138 (2019) 281-293.
[8] M. Ghashghaee, Thorough assessment of delayed coking correlations against literature data: Development of improved alternative models, React. Kinet. Mech. Cat., 126 (2018) 83–102.
[9] B.M. Souza, L. Travalloni, M.A.P. da Silva, Kinetic Modeling of the Thermal Cracking of a Brazilian Vacuum Residue, Energ. Fuel., 29 (2015) 3024–3031.
[10] S. Shirvani, M. Ghashghaee, S. Kegnæs, Dual role of ferric chloride in modification of USY catalyst for enhanced olefin production from refinery fuel oil, Applied Catalysis A: General, 580 (2019) 131-139.
[11] Z. Belohlav, P. Zamostny, T. Herink, The kinetic model of thermal cracking for olefins production, Chemical Engineering and Processing: Process Intensification, 42 (2003) 461–473.
[12] J.M. Simmie, Detailed chemical kinetic models for the combustion of hydrocarbon fuels, in: PECS, Department of Chemistry, National University of Ireland, Galway, Ireland, 2003.
[13] G. Bikas, Kinetic mechanisms for Hydrocarbon Ignition, in, Rheinisch-Westf¨alischen Technischen Hochschule Aachen, 2001.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper presents an interesting study about the kinetic modelling and simulation of the reaction network of a cracking furnace based on the enrichment of the Kumar model by free-radical reactions. The number of reactions of Kumar model (22) were significantly increased by the use of a radical reactions network. Finally, the model was validated by comparing the theoretical results with an industrial plant results. This paper contributes to quite novel knowledge to the related field, but it needs some improvements before acceptance for publication. The major comments are as follows:
(1) This manuscript was submitted to Processes to be considered to be published but there are no references to this journal in the bibliography. Why did the authors choose this journal? Please add some references to show the relation of your work with the journal scope.
(2) There are some english expressions that must be revised. In general, the paper has been written in poor english, making some explanations difficult to follow. Hence, please revise your english redaction.
(3) Abstract: Line 18, you say that the proposed model fits the industrial data well, but afterwards you include the sentence (2) that is in no relation with the industrial fit directly. Hence, I suggest to writte this expression as a new sentence.
(4) Keywords: I suggest to include kinetics or similar in the keywords to improve the manuscript classification.
(5) Line 31: do you refer to cash flow profits when you talk about the yield of billions of pounds?
(6) Line 35: a more accurate model than what? You have not talk about the Kumar model before (except in abstract).
(7) Line 39: Why do you think that other models are characterized by a limited utility? In engineering, models are often successful when they allow to design a specific chemical process. Can you explain a little bit more about the disadvantages of these models?
(8) Line 41: I don´t agree that a kinetic model that is not based in a mechanism reaction network can´t ensure the correctness of the chemical operations.
(9) Line 59: which reasons?
(10) Lines 73-80 (and more in the rest of the manuscript): the word "chapter" must be changed by "section" (or subsection, in case). In addition, all the acronyms must be defined at the first time that they are used. You can consider to include a table with all acronyms used in the text at the beginning of the article.
(11) Line 95: some references must be included or some equations must be explained to show the exponential growth.
(12) Lines 99-338: there are almost no references in all these lines. The Kumar model is a well-known kinetic model that has been applied by many research groups. Hence, some references must be included in the text when you explain typical values or the method itself.
(13) You should include only Tables and Figures in the manuscript. Schemes must be Tables, and Charts must be Figures.
(14) Lines 101-103: why these conditions are important? Can you provide some references to support these comments?
(15) Line 207: "listed above" means listed in Scheme 2?
(16) Some font types are mixed in the text.
(17) Line 325: in which previous study? Please specify.
(18) Line 332: MRE must be defined the first time that it is introduced in the text.
(19) Line 350: can you provide some information about the chaos algorithm? It could be of interest to explain why a chaos algorithm is used. Which advantages are observed when a chaos algorithm is used vs., for example, a method based on artificial intelligence?
(20) Tables 5-8: the K-R model relative errors are often very different from the Kumar relative errors (they also change from possitive to negative and vice versa). Does this mean that the improvement that it is presented in this manuscript could be not for application on other cracking systems because the results sensibility?
(21) Some figures are not in good resolution. Please provide some improved ones.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript developed an optimized Kumar model with free-radical reaction network for the ethylene cracking furnace modeling. Case analysis was conducted and the proposed model was validated with industrial data on the clean tube assumption. This work delivers some effort for the ethylene cracking furnace modeling field. However, there are still many issues needed to be addressed.
Nomenclature table or the explanations for the parameters are really needed. It is difficult to understand the text because most parameters in tables or figures are not defined. Rational introduction of the Kumar model is needed in the Part 1. The schemes, tables and figures are in poor quality. For example, in Scheme 2, there are two values in last column corresponding for one reaction. I cannot understand what are B, T, EB and ST in Scheme 3,Table 3 and Table4. Line 108, are all reactions listed in the Scheme 1 first-order reactions? Line 139, the authors described the sub-graph (a) to (d). But there is no such information in figure2. Part 4.4, even though the naphtha (4) to (9) cannot get the reasonable solution, their results should be listed in the supplementary materials. Chart 3 is confusing. The x-axis is “process of pyrolysis”, how to define this variables? For the y-axis, what are the values for the “industry product yield of propylene” and “industry product yield of ethylene”? In the case analysis, for different naphtha, are the kinetics parameters in the primary reaction different due to their different compositions ?
Overall, this manuscript is difficult to understand due to the poor quality of the tables, figures and language grammar.
Author Response
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments on Manuscript processes-665290R1:
I can agree that the authors have conducted an in-depth revision of their manuscript, addressing all comments to the required standards for acceptance. Then, I would recommend the publication of the manuscript.
Reviewer 2 Report
The manuscript has been significantly improved in the revised version in accordance with this reviewer comments. Therefore, I recommend to accept it in its actual form.
Reviewer 3 Report
In the revised manuscript, the authors have addressed reviewers’ comments and have made revision accordingly. The related data and references are offered. Also, some missing information is added. In summary, the quality of the manuscript is improved. Therefore, this revised manuscript is suggested to be accepted for publication.
