​​

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

    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