Simplified kinetic model for steam reforming of ethanol on a Ni/Al2O3 catalyst

Authors

  • Y.-J. Wu,

    1. Laboratory of Separation and Reaction Engineering (LSRE), Associated Laboratory LSRE/LCM, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
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  • J.C. Santos,

    1. Laboratory of Separation and Reaction Engineering (LSRE), Associated Laboratory LSRE/LCM, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
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  • Ping Li,

    1. State Key Laboratory of Chemical Engineering, College of Chemical Engineering, East China University of Science and Technology (ECUST), Shangai 200237, China
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  • J.-G. Yu,

    1. State Key Laboratory of Chemical Engineering, College of Chemical Engineering, East China University of Science and Technology (ECUST), Shangai 200237, China
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  • A.F. Cunha,

    1. Laboratory of Separation and Reaction Engineering (LSRE), Associated Laboratory LSRE/LCM, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
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  • A.E. Rodrigues

    Corresponding author
    1. Laboratory of Separation and Reaction Engineering (LSRE), Associated Laboratory LSRE/LCM, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
    • Author to whom correspondence may be addressed.

      E-mail address: arodrig@fe.up.pt

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Abstract

Ethanol steam reforming is a promising method for hydrogen production. Kinetic studies are carried out over a nickel-based catalyst from 200 to 600°C. A simplified Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic model was proposed with nine parameters, where the surface decomposition of methane is assumed as the rate determining step (RDS), and while all other reaction steps are set as reversible. It is postulated that the velocity of the backward reaction step of the dissociative methane adsorption math formula is similar to all other equilibrium reactions proposed, while the forward reaction step is set as the RDS. In addition, the formation of adsorbed carbon species is excluded due to the fact that SRE experiments were performed with excess water, suggesting that OH species, excluding O species formation, stick better on active Ni surface than methane. In addition, a power law kinetic model was used for analysis; the activation energy was 31.8 kJ/mol, and the reaction order of ethanol pressure was 1.52. Experimental results were successfully demonstrated by both kinetic models. The purpose of this work was to develop a simplified mechanistic model to replace empirical models (power rate model) and other proposed kinetic models that are too complex for an applied kinetic process. It was found that the simplified LHHW kinetic model has a better fit than that of the power law model. The proposed kinetic model works well over a wide temperature range (200–600°C).

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