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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

    The intrinsic effect of co-feeding water on the formation of active/deactivating species in the methanol-to-hydrocarbons reaction on ZSM-5 zeolite

    by Valecillos, Elordi, Aguayo, Castaño
    Catal. Sci. Technol. Year: 2021

    Abstract

    Water is formed and added in the conversion of methanol-to-hydrocarbons, slowing down both the reaction and deactivation rates. This work aims to clarify the selective nature of water quenching on a ZSM-5 zeolite catalyst in terms of (1) reaction/deactivation using an integral reactor (full range of conversions) and (2) rate of formation/growth of deactivating species using two FTIR and UV-vis in situ differential reactors (conversions lower than 0.15). Our approach assesses the effect of water under comparable conversion conditions while characterizing in detail the products and intermediates of the reaction (by online and in situanalysis, and extraction measurements). The results obtained prove, in an unbiased way, that water quenches more selectively the deactivation than the reaction with moderate amounts of added water (water/methanol = 0.11 g g−1). On the other hand, in situ FTIR spectroscopy evidences that co-feeding water sweeps the retained species from the silanol sites and favors the formation of olefins as retained species, while in situ UV-vis spectroscopy proves that the rate of formation/growth of discrete retained species drop by the addition of water and the degree of this decline is severer for coke than for coke precursors or active species.

    Keywords

    O2H