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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

    Simultaneous Modeling of the Kinetics for n-Pentane Cracking and the Deactivation of a HZSM-5 Based Catalyst

    by Cordero-Lanzac, Aguayo, Gayubo, Castaño, Bilbao
    Chem. Eng. J. Year: 2018

    Abstract

    A kinetic model for the catalytic cracking of n-pentane over a HZSM-5 zeolite (Si/Al = 15) based catalyst has been proposed. In this model, the kinetic scheme of reactions is based on the paraffin cracking mechanisms and uses lumps (light olefins, light paraffins, C5+ paraffins, aromatics and methane). The reaction steps of the scheme are related with the catalytic cracking routes: protolytic cracking, β-scission, oligomerization-cracking, hydride transfer, olefin condensation and methane formation. In addition, a kinetic deactivation equation has been used for modeling the catalyst deactivation, depending on the coke precursors (light olefins and aromatics) concentration. The catalyst has been prepared by agglomerating the HZSM-5 zeolite with a mesoporous matrix of weak acidity, using pseudoboehmite as a binder. The kinetic runs have been carried out in a fixed bed reactor using the following conditions: 350–550 °C, 1.4 bar, space time up to 1.1 gcat h−1 molC−1 and time on stream up to 15 h. The formation of olefins and aromatics, as well as the catalyst deactivation, are favored at high temperatures. A mathematical methodology based on the Levenberg-Marquardt algorithm has been used for the kinetic parameters estimation. The method has allowed for the simultaneous computing of the kinetic parameters of each step of the reaction scheme and the deactivation kinetics, from the experimental results of evolution with the time on stream of each lump concentration.

    Keywords

    O2H CHA MKM