​​

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

    Insight into the Deactivation and Regeneration of HZSM-5 Zeolite Catalysts in the Conversion of Dimethyl Ether to Olefins

    by Cordero-Lanzac, Ateka, Perez-Uriarte, Castaño, Aguayo, Bilbao
    Ind. Eng. Chem. Res. Year: 2018

    Abstract

    The impact of different process variables affecting the coking and rejuvenation of HZSM-5 zeolite catalyst has been studied during the conversion of dimethyl ether (DME) to olefins in a fixed bed reactor. Those variables involve the effect of (i) the matrix material with mesopores; (ii) temperature; (iii) space time; (iv) acidity of the catalyst; (v) steam, inert or air in the reaction-regeneration medium. Used catalysts have been characterized through N2 adsorption-desorption and temperature-programmed oxidation, and the presence of three coke fractions has been identified, deposited within the zeolite micropores, the external surface of the crystals and the mesopores of the matrix. Low Si/Al ratios (140) and temperatures (350 °C), and cofeeding water with DME, reduce the formation of coke within the zeolite micropores, favoring the stability of the catalyst. Reaction-regeneration cycles confirm that catalysts totally recover the activity through combustion of coke during a heating ramp up to 550 °C.

    Keywords

    O2H MKM