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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

    Slowing down the deactivation of H-ZSM-5 zeolite catalyst in the methanol-to-olefin (MTO) reaction by P or Zn modifications

    by Valecillos, Epelde, Albo, Aguayo, Bilbao, Castaño
    Catal. Today Year: 2020

    Abstract

    The benefits of H-ZSM-5 zeolite modification with H3PO4 or ZnCl2 have been analyzed during the methanol to olefins (MTO) reaction. The catalysts were prepared, characterized and tested using three different reactors: fixed-bed, operando FTIR and UV–vis. The spent catalysts were further characterized for analyzing the nature and location of the species trapped. The results show that the zeolite modified with H3PO4 has suffered a simultaneous dealumination, leading to a decrease of number of acid sites and activity. However, the zeolite modified with ZnCl2 shows the inclusion of Zn transforming Brønsted into Lewis acid sites, leading to reaction intermediates (hydrocarbon pool species) that decreases the rate of reaction but improves propylene selectivity (+10%), slows downs coke formation (-42%) and expands catalytic lifetime (+80%). The distinct effect of Zn modification, typically associated with the promotion of aromatics, is explained on the grounds of the severe transformation of the strong and Brønsted acid sites.

    Keywords

    O2H HCE CRE