Deactivation routes in zeolite catalyzed isobutane/2-butene alkylation and regeneration procedures [Elektronische Ressource] / Iker Zuazo

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• Publié par: technische_universitat_munchen
• Publié le: 01 janvier 2004
• Nombre de lectures: 14
• Langue: English

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Technische Universität München
Lehrstuhl für Technische Chemie II


Deactivation Routes in Zeolite Catalyzed Isobutane/2-Butene
Alkylation and Regeneration Procedures

Iker Zuazo

Vollständiger Abdruck der von der Fakultät für Chemie der Technischen Universität
München zur Erlangung des akademischen Grades eines

Doktors der Naturwissenschaften

genehmigten Dissertation.


Vorsitzender: Univ.-Prof. Dr. Thorsten Bach

Prüfer der Dissertation:
1. Univ.-Prof. Dr. Johannes A. Lercher
2. Univ.- Prof. Dr. Frank H. Köhler




Die Dissertation wurde am 06.05.2004 bei der Technischen Universität München
eingereicht und durch die Fakultät für Chemie am 27.05.2004 angenommen. Acknowledgments

Everything comes to an end and, as somebody sang, “nothing lasts forever”. I have to
say...yes, nothing lasts forever...but these three years of my life will stay always deep
inside me, and nobody can take them out. Besides that, time run like hell...but, of course,
that would not be in this way without all the good moments (in- and outside the Uni) with
my (already missed) colleagues.
First of all, I would like to give one million thanks to the great group dealing with
alkylation at TCII. Johannes, it was a great experience to work with you. We went
through easier and more difficult times, times full of stress and also more relaxed times,
but at the end of the day, you were always very fair with me, you took always all the time
I needed to discuss, and you trusted in me from the beginning. I think we did a good job
together and we were successful with our tasks. I had quite a lot of fun with your secret
feeling for science (“aus dem Bauch heraus...”) but I have to recognize that it worked
many of the times. You were the guide I needed and you showed me how to work as a
professional and, therefore, I feel indebted to you. Following with the group of
alkylation…Alex and Andreas...well...what can I say about you two, guys? If I could
choose a team for my future working life...both of you would be in my team, no doubt
about it. It was really a pleasure to work with you. We had a lot of fun, we learned a lot
together, and I think we were somehow something more than only “lab-colleagues”. I
will miss you a lot, and I hope we can see each other in the next (but not too far...) future.
I enjoyed very much all these conversations about similarities-dissimilarities among our
countries. Alex, I will never forget these couple of beers at the “Scharfes-Eck” in
Garching at the beginning of the times...and now, going to more recent times, I would
like to thank Hitri for her huge help. It was not only a pleasure but also very funny to
work with you. Without your help I would have needed even the next life to finish all the
experiments I wanted to do. Try not to forget all the Spanish that you learned from me,
ok? I also want to thank Carsten for the MALDI measurements. Roberta, thank you for
all the important corrections you did.
I would also like to say thanks to Xaver Hecht and Andreas Marx. I have never seen
so nice setups as the ones you built. You are a genius in this topic and, well, without your
i help there would be no way to run reactions. Thanks a lot.
I am also very indebted to all these people that talked to me in German even when it
was completely impossible to understand what I wanted to say, and specially Andreas,
Christian, Philipp(s), Hendrik (vielen Dank für die Korrektur!), Maria, Su, Jan Olaf,
Peter, Josef...and all the rest. Danke euch! Ihr habt mir aber viel geholfen! (Phillip und
Peter, es war super mit euch joggen zu gehen...).
I know that with my legendary memory I would forget to thank a couple of you and,
that is why, I would like to do it in a more general way. Thank you, TCII group, it was
really a pleasure to share this time with you.
I would also like to thank my Spanish friends from München...you gave me the
necessary support to finish the thesis.
And now, going a bit more to the inside...I do not know if “thanks” is the right word,
but somehow I would like to say something like that to all my family (Aita, Ama, Laika,
Javi, Maite, Gonzalo, Ana, June) for all the mountains of love and help you gave me in
these past years. Esti, I would specially like to thank you for all your help during the
thesis and for all your support during this (sometimes hard) time. I will never forget the
nights that I had to spend in the Lab doing reactions/regenerations...it was more than a
dream to see you coming with the dinner and a glass of wine...thank you again four your
support and for your love.

Iker



ii 1. Chapter 1
General introduction

1.1 Introduction to the alkylation process 1
1.2 Reaction/side-reactions mechanism overview 2
1.3 Deactivation/regeneration of zeolites 5
1.4 References 7

2. Chapter 2
Detailed time-on-stream/deactivation study in zeolite catalyzed
iso-butane/butene alkylation

2.1 Introduction 10
2.2 Experimental 11
2.2.1 Catalyst preparation
2.2.2 Catalytic experiments 11
2.2.3 Catalyst characterization 13
2.2.4 Alkylate analysis
2.2.5 Characterization of used zeolites 13
2.3 Experimental results and interpretation 15
2.3.1 Physicochemical characterization
2.3.2 Alkylation of iso-butane with n-butene 16
2.3.3 Alkylate characterization 19
2.3.4 Characterization of coked catalysts 22
2.3.5 Recovered deposits analysis 29
2.4 Discussion 33
2.4.1 Main alkylation mechanism and product selectivity overview
2.4.2 Alkylate quality evolution with time-on-stream 36
2.4.3 Chemical nature of the deposits
2.5 Conclusions 42
2.6 References


iii 3. Chapter 3
Impact on the alkylate produced and accumulated deposits for
different performing catalysts in iso-butane/butene alkylation

3.1 Introduction 46
3.2 Experimental 47
3.2.1 Catalyst preparation 47
3.2.2 Catalytic experiments
3.2.3 Catalyst characterization 49
3.2.4 Alkylate analysis
3.2.5 Coke zeolite characterization 50
3.3 Experimental results and interpretation 50
3.3.1 Physicochemical characterization 50
3.3.2 Alkylation experiments 52
3.3.3 Alkylate characterization 57
3.3.4 Characterization of coked catalysts 63
3.3.5 Analysis of recovered deposits 68
3.4 Discussion 70
3.4.1 Physicochemical properties influencing the performance of a catalyst
for the iso-butane / 2-butene alkylation reaction and their impact on the
quality of the alkylate produced 70
3.4.2 Alkylate quality evolution with time-on-stream 71
3.4.3 Chemical nature of the deposits 72
3.5 Conclusions 74
3.6 References 75

4. Chapter 4
Product characteristics during a stable solid acid catalyzed iso-
butane/2-butene reaction

4.1 Introduction 78
4.2 Experimental 79
4.3 Experimental results and interpretation 81
4.3.1 Single reaction and reaction steps during the long-term experiment 81
iv 4.3.2 Mild-regeneration step during the long-term experiment 85
4.3.3 Hard-regeneration step during-term experiment 87
4.3.4 Overall alkylation reaction over more cycles 88
4.4 Discussion 94
4.4.1 Catalyst performance 94
4.4.2 Comparison of the quality of the product between a single reaction
and a set of reactions/mild-regenerations 95
4.4.3 Cracked products during the hard-regeneration step 96
4.5 Conclusions 99
4.6 Acknowledgments 100
4.7 References 100

5. Summary 102
6. Zusammenfassung 104
7. Resumen 106














v Chapter 1

General Introduction



1.1 Introduction to the alkylation process
In chemistry, the term alkylation comprises a variety of reactions, which have in common
that an alkyl group of an arbitrary (but usually well defined) carbon number is introduced into
an arbitrary substrate by means of an alkylating agent, typically alkene, an alcohol, or an alkyl
halide [1]. Alkylation within the petroleum refining industry more specifically refers to a
process positioned downstream of the fluid catalytic cracking unit (FCCU, [2]) and is meant
to convert part of the C hydrocarbons formed as by-products in the FCCU into the so-called 4
“alkylate”