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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

    A global methanol-to-hydrocarbons (MTH) model with H-ZSM-5 catalyst acidity descriptors

    by Vicente, Aguayo, Castaño, Gayubo
    Fuel Year: 2024 DOI: https://doi.org/10.1016/j.fuel.2024.132777

    Abstract

    This work presents a dual cycle-based kinetic model that uses H-ZSM-5 catalyst acidity descriptors for the methanol-to-hydrocarbons (MTH, -olefins, MTO, and –aromatics, MTA) processes. This model was developed using data obtained in 12 periodic reactions with three H-ZSM-5 zeolites of different acidity (Si/Al = 15, 40 and 140). We decoupled the kinetics of the model from the catalyst identity by linking the calculation of the kinetic parameters to the zeolite acidity, allowing us to perform simulations of the reactor operating under various conditions and with different zeolite acidity values different from those used experimentally. The results obtained in the simulations let us identify the best operating conditions for the MTO and MTA processes, and pointed at the main difficulties found when implementing these two technologies industrially. In addition, the conditions and values obtained for the target products, either light olefins or aromatics, were comparable with those presented by several existing works in the literature for H-ZSM-5 zeolites of similar acidity. Moreover, the methodology detailed here using acidity descriptors can be extrapolated for its application to other catalytic processes.

    Keywords

    MKM O2H