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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.

Goals

  • Develop a quantitative analytical workflow to analyze and interpret these complex reacting environments
  • Explore novel renewable and waste resources to obtain chemicals and fuels
  • Deploy ad-hoc catalysts and process conditions to incorporate these wastes in the refinery (bio- and waste-refinery)
  • Analyze process dynamics and kinetics
OLG2023

Related People

Hend Omar Mohamed
Kiruthika Jayaseelan
Rushana Khairova

Related Publications

Direct analysis at temporal and molecular level of deactivating coke species formed on zeolite catalysts with diverse pore topologies

by Hita, Mohamed, Yerrayya, Zambrano, Zhang, Ramirez, Castaño
Catal. Sci. Technol. Year: 2023 DOI: https://doi.org/10.1039/D2CY01850K

Abstract

he mechanistic understanding of coke formation on zeolites is elusive, given the limitations for the extraction and analysis of coke species. Here, we analyze the evolution of deactivating coke species over time on the surface of Ni/ZSM-5, β and Y zeolites during ethylene oligomerization, which is a representative coke-forming reaction. We present a method that directly analyzes the coke species using high-resolution mass spectrometry on the used catalysts and their isolated soluble and insoluble coke fractions (indirect analysis). Along with other techniques, we report a full-picture temporal evolution of coke and its fractions at the molecular level to establish a correlation between the dominant reaction mechanisms, the location of coke within the catalyst structure, and the observed performance of the catalysts. Ab initio calculations are performed to understand the preferable location of coke. We delve deep into the peculiar deactivation mechanism of ZSM-5 zeolite (MFI structure), which shows two less intuitive parallel deactivation pathways.

Keywords

OLG ANW