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Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor

Received: 7 November 2025     Accepted: 18 November 2025     Published: 29 December 2025
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Abstract

Maleic anhydride is a key intermediate in the chemical industry, predominantly produced through the partial oxidation of n-butane over vanadium-phosphorus-oxide (VPO) catalysts. This reaction is accompanied by side reactions that lead to the formation of undesired by-products, primarily CO and CO2. In this work, a previously developed mathematical model of a fixed-bed tubular reactor was extended to include a catalyst activity function accounting for catalyst deactivation, and the kinetic parameters were optimized using experimental data from an industrial reactor at Koksara d.o.o. Lukavac. The model describes the partial oxidation of n-butane to maleic anhydride through multiple reactions, with reaction rates expressed as functions of temperature, partial pressures, and catalyst activity. Numerical simulations were performed using MATLAB, employing a nonlinear least-squares solver to minimize the deviation between the predicted and measured temperature profiles along the reactor. The validated model showed good agreement with experimental data, demonstrating its capability to accurately simulate reactor behavior under typical industrial conditions. Parametric studies were conducted to analyze the effects of inlet n-butane and oxygen flow rates, reaction mixture temperature, and pressure on the formation of CO and CO2. The results indicate that by-product formation is strongly influenced by the oxygen/n-butane ratio, temperature, pressure, and the catalyst oxidation state. Higher oxygen flow rates and elevated temperatures increase CO and CO2 formation, while lower values reduce their production. Changes in n-butane flow have a minor effect on CO2, but more pronounced effects on CO due to the interplay between partial and complete oxidation at different catalyst sites. Increasing the inlet pressure enhances by-product formation by increasing reactant concentrations, whereas reduced pressure decreases CO and CO2 formation. The developed model provides a practical tool for understanding and optimizing industrial maleic anhydride production. It offers insights into the effects of key process parameters on by-product formation, supporting improved reactor operation, reduced trial-and-error experimentation, and more efficient industrial process design.

Published in American Journal of Chemical and Biochemical Engineering (Volume 9, Issue 2)
DOI 10.11648/j.ajcbe.20250902.12
Page(s) 57-66
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Maleic Anhydride, N-butane Oxidation, Fixed-bed Tubular Reactor, VPO Catalyst, Mathematical Modeling, Kinetic Parameters, By-product Formation

References
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  • APA Style

    Karic, E., Petric, I. (2025). Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor. American Journal of Chemical and Biochemical Engineering, 9(2), 57-66. https://doi.org/10.11648/j.ajcbe.20250902.12

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    ACS Style

    Karic, E.; Petric, I. Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor. Am. J. Chem. Biochem. Eng. 2025, 9(2), 57-66. doi: 10.11648/j.ajcbe.20250902.12

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    AMA Style

    Karic E, Petric I. Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor. Am J Chem Biochem Eng. 2025;9(2):57-66. doi: 10.11648/j.ajcbe.20250902.12

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  • @article{10.11648/j.ajcbe.20250902.12,
      author = {Ervin Karic and Ivan Petric},
      title = {Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor},
      journal = {American Journal of Chemical and Biochemical Engineering},
      volume = {9},
      number = {2},
      pages = {57-66},
      doi = {10.11648/j.ajcbe.20250902.12},
      url = {https://doi.org/10.11648/j.ajcbe.20250902.12},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajcbe.20250902.12},
      abstract = {Maleic anhydride is a key intermediate in the chemical industry, predominantly produced through the partial oxidation of n-butane over vanadium-phosphorus-oxide (VPO) catalysts. This reaction is accompanied by side reactions that lead to the formation of undesired by-products, primarily CO and CO2. In this work, a previously developed mathematical model of a fixed-bed tubular reactor was extended to include a catalyst activity function accounting for catalyst deactivation, and the kinetic parameters were optimized using experimental data from an industrial reactor at Koksara d.o.o. Lukavac. The model describes the partial oxidation of n-butane to maleic anhydride through multiple reactions, with reaction rates expressed as functions of temperature, partial pressures, and catalyst activity. Numerical simulations were performed using MATLAB, employing a nonlinear least-squares solver to minimize the deviation between the predicted and measured temperature profiles along the reactor. The validated model showed good agreement with experimental data, demonstrating its capability to accurately simulate reactor behavior under typical industrial conditions. Parametric studies were conducted to analyze the effects of inlet n-butane and oxygen flow rates, reaction mixture temperature, and pressure on the formation of CO and CO2. The results indicate that by-product formation is strongly influenced by the oxygen/n-butane ratio, temperature, pressure, and the catalyst oxidation state. Higher oxygen flow rates and elevated temperatures increase CO and CO2 formation, while lower values reduce their production. Changes in n-butane flow have a minor effect on CO2, but more pronounced effects on CO due to the interplay between partial and complete oxidation at different catalyst sites. Increasing the inlet pressure enhances by-product formation by increasing reactant concentrations, whereas reduced pressure decreases CO and CO2 formation. The developed model provides a practical tool for understanding and optimizing industrial maleic anhydride production. It offers insights into the effects of key process parameters on by-product formation, supporting improved reactor operation, reduced trial-and-error experimentation, and more efficient industrial process design.},
     year = {2025}
    }
    

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  • TY  - JOUR
    T1  - Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor
    AU  - Ervin Karic
    AU  - Ivan Petric
    Y1  - 2025/12/29
    PY  - 2025
    N1  - https://doi.org/10.11648/j.ajcbe.20250902.12
    DO  - 10.11648/j.ajcbe.20250902.12
    T2  - American Journal of Chemical and Biochemical Engineering
    JF  - American Journal of Chemical and Biochemical Engineering
    JO  - American Journal of Chemical and Biochemical Engineering
    SP  - 57
    EP  - 66
    PB  - Science Publishing Group
    SN  - 2639-9989
    UR  - https://doi.org/10.11648/j.ajcbe.20250902.12
    AB  - Maleic anhydride is a key intermediate in the chemical industry, predominantly produced through the partial oxidation of n-butane over vanadium-phosphorus-oxide (VPO) catalysts. This reaction is accompanied by side reactions that lead to the formation of undesired by-products, primarily CO and CO2. In this work, a previously developed mathematical model of a fixed-bed tubular reactor was extended to include a catalyst activity function accounting for catalyst deactivation, and the kinetic parameters were optimized using experimental data from an industrial reactor at Koksara d.o.o. Lukavac. The model describes the partial oxidation of n-butane to maleic anhydride through multiple reactions, with reaction rates expressed as functions of temperature, partial pressures, and catalyst activity. Numerical simulations were performed using MATLAB, employing a nonlinear least-squares solver to minimize the deviation between the predicted and measured temperature profiles along the reactor. The validated model showed good agreement with experimental data, demonstrating its capability to accurately simulate reactor behavior under typical industrial conditions. Parametric studies were conducted to analyze the effects of inlet n-butane and oxygen flow rates, reaction mixture temperature, and pressure on the formation of CO and CO2. The results indicate that by-product formation is strongly influenced by the oxygen/n-butane ratio, temperature, pressure, and the catalyst oxidation state. Higher oxygen flow rates and elevated temperatures increase CO and CO2 formation, while lower values reduce their production. Changes in n-butane flow have a minor effect on CO2, but more pronounced effects on CO due to the interplay between partial and complete oxidation at different catalyst sites. Increasing the inlet pressure enhances by-product formation by increasing reactant concentrations, whereas reduced pressure decreases CO and CO2 formation. The developed model provides a practical tool for understanding and optimizing industrial maleic anhydride production. It offers insights into the effects of key process parameters on by-product formation, supporting improved reactor operation, reduced trial-and-error experimentation, and more efficient industrial process design.
    VL  - 9
    IS  - 2
    ER  - 

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