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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

    SAPO-18 and SAPO-34 Catalysts for Propylene Production from the Oligomerization-Cracking of Ethylene or 1-Butene

    by Epelde, Ibanez, Valecillos, Aguayo, Gayubo, Bilbao, Castaño
    Appl. Catal. A: Gen. Year: 2017

    Abstract

    The performance of SAPO-18 and SAPO-34 catalysts has been compared during the conversion of ethylene or 1-butene to propylene. This comparison has been made in terms of activity (conversion), selectivity and stability against coke deposition. The SAPOs were synthesized, agglomerated, calcined, characterized and tested in a fixed-bed reactor at 500 °C. The spent catalysts (after 5 h on stream) were characterized to assign the location and nature of coke. The results point to the higher activity and stability of SAPO-18 catalyst in the conversions of each reactant (ethylene or 1-butene), which has been explained on the basis of its acidity, pore topology and above all, the faster diffusion of aromatics causing deactivation. Thus, the SAPO-18 catalyst suffers slower coke deposition, while this coke is of lighter nature (more aliphatic and less aromatic). The advantages of SAPO-18 over SAPO-34 catalyst are more relevant for the transformation of 1-butene, where the propylene selectivity and yield increase over time, as secondary reactions are selectively neglected and coke condensation is slowed down.

    Keywords

    OLG HCE