Education

Research Projects

Below, an overview is given of all possible research projects within the theoretical / computation chemistry subgroup. For each project, an indication is given whether this project is feasible for a Bachelor Final Project, a Capita Selecta or a Master Final Project.

Description Type
Multiscale reactor modelling based on microkinetics and machine learning.

Contemporary reactor modeling uses relatively simple chemokinetic rate expressions. As a step forward, a hierarchical reactor model is constructed wherein the fundamental kinetics are based on highly accurate microkinetic simulations. Since the direct evaluation of microkinetics is too cost-intensive for more advanced reactor models, an artificial neural network is built that captures all reaction kinetics. This ANN then acts as the kinetic model in the overall reactor simulation, significantly reducing the computational cost making such simulations computationally feasible.

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Bachelor Final Project
Capita Selecta
Master Final Project
Exploring kinetic modules in the description of catalytic reactors

Numerical modeling of catalytic reactors remains a challenging task due to the complex interplay of transport and reactive processes. The underlying mathematical description, typically based on finite difference, finite volume or finite element discretization, exhibits inherently stiff equations. As such, the modeling of more complex chemo-kinetic networks requires some form of coarse-graining that simplifies the equations involved by which the overall numerical routines remain tractable on modern computational infrastructures. In this project, we aim to explore the different types of coarse graining methodologies to describe reactive events in the catalytic reactor and study the effect of this choice on the overall interplay between transport and reaction.

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Bachelor Final Project
Capita Selecta
Master Final Project
Modeling catalyst deactivation in cobalt-based Fischer-Tropsch synthesis

Cobalt-based Fischer–Tropsch synthesis (FTS) catalysts are an integral part of the gas-to-liquid (GTL) process. Due to the cost of both cobalt and noble metals, which are often used as promoters, an extended catalyst life is required to make the process economically feasible. Fundamental understanding of the deactivation mechanisms at play during FTS is key to extending catalyst lifetime. Current insights in the deactivation process point out that carbon deposition and surface reconstruction are two important deactivation mechanisms. In this study, we aim at building a mesoscale ReaxFF-based model to describe such processes.

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Bachelor Final Project
Capita Selecta
Master Final Project
Predicting the surface topology of iron carbide nanoparticles

Iron-based Fischer–Tropsch catalysts, which are applied in the conversion of CO and H2 into longer hydrocarbon chains, are historically amongst the most intensively studied systems in heterogeneous catalysis. Despite this, fundamental understanding of the complex and dynamic chemistry of the iron-carbide system is still a developing field. One prominent question is what active sites are exposed under typical process conditions. There are many iron-carbide phases and each phase can expose a variety of surface facets. In turn, these surface facets harbor a variety of active sites. To construct an atomic/mechanistic kinetic model of Fisher-Tropsch synthesis, it is critical that the stability and presence of these active sites is known.

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Bachelor Final Project
Capita Selecta
Master Final Project

Books

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Introduction to Microkinetics

Molecular catalysis has revealed that the macroscopic phenomena observed in experiments are caused by the emergent behavior of very small particles guided by the laws of quantum mechanics. Remarkably, these quantum effects are propagated over roughly ten orders of magnitude, at which point their behavior is considered to be classic.

Within this work, we will elaborate on the connection between the smallest quantum scale and the larger macroscopic scale, providing a theoretical framework on which many kinetic studies in heterogeneous catalysis are based. We will focus on the underlying quantum chemical mechanism leading to the observed overall rate laws in chemistry and process engineering.

ISBN: 978-90-386-4520-9

Quantum Chemical and Microkinetic Modeling of the Fischer-Tropsch Reaction

In this dissertation, the kinetics and mechanism of the Fischer-Tropsch reaction are investigated. The Fischer-Tropsch reaction is a very complex reaction involving many elementary reaction steps. The rate of these steps depends in a sensitive manner on the type of transition metal, the surface metal atom topology and the composition of the adsorbed layer. While density functional theory methods provide accurate data for the rate constants for these elementary reaction steps, microkinetics simulations allow to predict the compositon of the adsorbed layer on the surface as well as the rates of all elementary reaction steps. In this manner, important issues can be resolved that pertain to the mechanism of the ­Fischer-Tropsch reaction such as the dominant reaction pathway from reactants (CO and H2) to products (alkanes, alkenes, oxygenates and water). Pertinent questions relevant to the Fischer-Tropsch reaction treated in this thesis are as follows. What is the manner of CO dissociation? Which of the two main proposed mechanisms for chain growth - the carbide mechanism or the CO insertion mechanism - dominates? What are the rate-controlling steps and which elementary reaction steps influence the product selectivity?

ISBN: 978-90-386-3793-8