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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

    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