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Controlling the selectivity–stability tradeoff in zeolite catalysis: oligomerization–alkylation, cracking, and methanol-to-hydrocarbons 


    Problem Statement

    Olefins and aromatics are commodity chemicals used in producing plastics (in the petrochemical industry), lubricants, plasticizers, and surfactants, among other products. However, there is an imbalance between their production and demand, which reactions like oligomerization, alkylation, and cracking over zeolites could help address. At the same time, zeolites serve as excellent catalysts for converting methanol to hydrocarbons (MTH), olefins (MTO), or aromatics (MTA). These processes aim to produce light hydrocarbons such as propylene or to convert ethylene into higher-value alpha-olefins, aromatic hydrocarbons (BTX), and jet fuel.


    Our focus in this project is to synthesize, modify, and develop new catalysts with engineered porosity at multiple scales: from hierarchical and hollow zeolites to catalytic particles, bodies, or technical catalysts intended for implementation. Additionally, we incorporate various metals (e.g., Ni, Cr, Zn) to influence the selectivity toward the desired products.

    We utilize various reactors, including forced dynamic, operando, high-throughput packed-bed, and batch reactors.

    OLG-O2H

    Goals

    • Control the catalyst structure to balance selectivity and stability.
    • 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

    Faseeh Kulangara Kandiyil
    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