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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

    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