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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

    Quenching the Deactivation in the Methanol-to-Olefin Reaction by Using Tandem Fixed-Beds of ZSM-5 and SAPO-18 Catalysts

    by Valecillos, Tabernilla, Sastre, Aguayo, Castaño
    Ind. Eng. Chem. Res. Year: 2020

    Abstract

    We proved that the disposition of tandem fixed-beds of ZSM-5 with SAPO-18 catalysts could decrease the deactivation of the second catalytic bed during the methanol-to-olefin reaction. For this purpose, we prepared two catalysts based on ZSM-5 zeolite and SAPO-18 zeotype; characterized them using XPS, XRD, 29Si NMR, N2 physisorption, NH3-TPD, and Fourier-transform infrared (FTIR); tested them individually, in mixed or tandem forms using a fixed-bed reactor or in situ reactors monitored with UV–vis or FTIR spectroscopies; and characterized the catalyst during the reaction or after it. The catalytic beds (mixed or tandem) did not offer any significant enhancement or synergetic effect in product selectivity. However, the catalytic lifetime of the second bed in the tandem catalytic beds (particularly if that is made up of the SAPO-18 catalyst) was prolonged because this bed receives less oxygenates (methanol and dimethyl ether) and more water, which slows down the deactivation of the second catalytic bed.

    Keywords

    O2H CRE