Designing, Evaluating, and Modeling Ni/Zeolite Heterogeneous Catalyst for Ethylene Oligomerization

Chemical Engineering Ph.D. Dissertation



Ethylene oligomerization is one of the major processes in the chemical industry. It is mainly conducted through homogeneous catalysis. Many heterogeneous catalysts have been proposed and studied over the years, and the Ni/zeolite is a viable system. However, many aspects still need to be clarified. 

This work aims to push the boundaries of ethylene oligomerization to make it more feasible. First, we reviewed the current literature to understand the process holistically and identify the research objectives. Next, we screened multiple zeolites with different physical and chemical properties to determine the highest-performing catalysts and their characteristics. We found a strong framework dependence on selectivities, especially in the oligomerization products. We concluded that Ni on ZSM-5 and Beta zeolites are the most attractive catalysts. We developed a methodology for evaluating catalysts using pulse adsorption and reaction experiments.

This enabled us to highlight the effects of acidity, Ni, and pore topology, especially in the early stages of the reaction. MFI catalyst has a higher ethylene uptake, while BEA retains ethylene longer and slowly desorbs. The addition of Ni promotes dimerization in both topologies. However, the contribution of acid sites is more significant in MFI than BEA, which deactivates quickly.  We found that the framework plays an important role in determining the reaction progression. Our results show that a co-functional catalyst is a better description than often used bi-functional. Given the importance of Ni2+ in the reaction mechanisms, we developed a method to encapsulate these sites on a hollow ZSM-5 zeolite. We developed a micro-kinetic model over various temperatures and pressures. With this model, we confirmed the cascade-insertion mechanism for ethylene oligomerization. Finally, we demonstrate applying a dual-bed cascade reactor system to convert dilute ethylene streams from CO2 electrochemical reduction cells with co-feeds of H2 and CO2 to fuel-range hydrocarbons.


CE Ph.D. candidate Omar Arshad Abed

CE Ph.D candidate supervised by Professor Pedro Castaño

Event Quick Information

20 Nov, 2023
01:30 PM - 03:00 PM
KAUST, Building 9, Level 2, Lecture Hall 2322 جامعة الملك عبدالله للعلوم والتقنية Saudi Arabia