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Controlling selectivity and stability of zeolite catalysts for methanol to hydrocarbons and ethylene oligomerization


    Problem Statement

    Olefins are commodity chemicals with applications in the production of plastics (petrochemical industry), lubricants, plasticizers, and surfactants, among many others. However, there is an imbalance between their production and demand, which oligomerization-cracking reactions over zeolites could solve. At the same time, zeolites are excellent catalysts for methanol to hydrocarbons (MTH), olefins (MTO), or aromatics (MTA). The processes aim to produce light hydrocarbons like propylene or convert ethylene into higher-value a-olefins, aromatic hydrocarbons (BTX), and jet fuel.

    Our focus in this project is to modify, synthesize, and develop novel materials of different porosity (engineered at the multiscale): from hierarchical zeolites, nano zeolites, and hollow zeolites to catalytic particles, bodies, spray-dried, and extrudates with tuned properties. Additionally, we incorporate different metals (i.e., Ni, Cr, Zn) to adjust the selectivity of desired products.

    We use various reactors, such as operando or high-throughput packed-bed and batch reactors.

    OLG-O2H

    Goals

    • Control structure–selectivity: Tune zeolite porosity and acidity to maximize propylene and α-olefin yields.
    • Metal modulation: Use Ni, Cr, Zn to bias reaction pathways and improve selectivity to target hydrocarbons.
    • Deactivation control: Reduce coke formation and extend catalyst lifetime with regeneration strategies.
    • Reactor optimization: Shape catalysts into bodies/extrudates and validate 100 h continuous stable operation.

    Related People

    Hend Omar Mohamed
    Kiruthika Jayaseelan

    Related Publications

    Dual-cycle-based lumped kinetic model for methanol-to-aromatics (MTA) reaction over H-ZSM-5 zeolites of different Si/Al ratio

    by Vicente, Aguayo, Castaño, Gayubo
    Fuel Year: 2024 DOI: https://doi.org/10.1016/j.fuel.2023.130704

    Abstract

    In this work we developed a 7-lump kinetic model for the methanol-to-aromatics (MTA) reaction based on the dual-cycle mechanism, with consideration of deactivation of the catalyst by coke formation and applicable to H-ZSM-5 zeolite-based catalysts of different acidity. The model developed is suitable to be implemented at an industrial scale, as the intrinsic kinetic aspect fits the experimental data in a wide range of operating conditions. Moreover, the model is validated for two catalysts (prepared from two H-ZSM-5 zeolites of Si/Al ratio = 15 and 40), and considers a combined formation of coke from both unreacted oxygenates and reaction products (specifically, aromatics and light olefins). The final model comprises 10 reaction steps, and considers the effect of water co-feeding. The kinetic parameters of best fitting are obtained in the simultaneous fitting of the zero time and the deactivation kinetics. We compared the kinetic parameters of the best-fitting model for the two catalysts and related the differences obtained between both sets of parameters to catalyst properties.

    Keywords

    MKM O2H