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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

    Selective Dealumination of HZSM-5 Zeolite Boosts Propylene by Modifying 1-Butene Cracking Pathway

    by Ibanez, Epelde, Aguayo, Gayubo, Bilbao, Castaño
    Appl. Catal. A: Gen. Year: 2017

    Extra Information

    Feature Article.

    Abstract

    An HZSM-5 zeolite was dealuminated by steaming with its self-adsorbed water at mild temperatures (300, 400 or 500 °C), characterized and tested in the transformation of 1-butene into propylene. The structural, porous-surface and acidic properties of the catalysts (unmodified and steamed) were characterized using N2 adsorption-desorption isotherms, tert-butylamine adsorption-TPD, XRD, 29Si and 27Al MAS-NMR, and FTIR spectroscopies, and the results pointed to the following evidences: (i) dealumination took place transforming specific strong acid, framework tetrahedral Al sitings (located within the micropores) into distorted and extra-framework species; and (ii) the porous-surface properties were less sensible to the treatment. The acid site density was shifted towards the intersections of the zeolite micropores (of weaker acidity), resulting in the selective inhibition of hydrogen transfer pathway, thus lowering the selectivity of paraffins, aromatics and ultimately, coke deposition. Overall, the performance of the 500 °C-steamed catalyst compared with the parent one was enhanced: propylene selectivity was boosted 69%, coke deposition dropped by 34%, whereas the initial conversion only fell 6%.

    Keywords

    OLG MKM