Thermal Degradation of Aqueous Amines Used for Carbon Dioxide Capture

307 Pages·2009·2.48 MB·English

Copyright
by
Jason Daniel Davis
2009
The Dissertation Committee for Jason Daniel Davis Certifies that this is the
approved version of the following dissertation:

Thermal Degradation of Aqueous Amines Used for Carbon Dioxide
Capture

Committee:

Gary Rochelle, Supervisor
Alan Campion
James Critchfield
Jennifer Maynard
Grant Willson
Thermal Degradation of Aqueous Amines Used for Carbon Dioxide
Capture

by
Jason Daniel Davis, B.S.

Dissertation
Presented to the Faculty of the Graduate School of
The University of Texas at Austin
in Partial Fulfillment
of the Requirements
for the Degree of

Doctor of Philosophy

The University of Texas at Austin
August 2009
Dedication

To my wife Niki and my new daughter Jocelyn whose love and support have helped me
through this process and will sustain me in future endeavors.
Acknowledgements

I would like to start by thanking my supervisor Dr. Rochelle. His enthusiasm for
his work is infectious and his eagerness to teach makes it difficult not to learn something
new from each meeting or conversation. While many professors are more focused on
research over teaching, I have always viewed him as a teacher first, and researcher
second. As a manager, he treats his students with respect giving guidance where needed
while allowing for the advancement of individual ideas. Despite the growth in our
research group during my tenure, he has always been accessible and responsive to the
needs of his students. He is a family man and not afraid to encourage his students to
balance life outside of the lab with the demands of research. This has made my graduate
school experience, while being married and having my first child, much smoother than it
should have been. I will always be grateful for my time under his tutelage and if given
another opportunity to choose a professor, I would not hesitate to make the same
decision.
Without the financial support of our generous research sponsors, The Luminant
Carbon Management Program and the U. S. Department of Energy, this project would not
have been possible.
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I would also like to thank the other members of the Rochelle group throughout my
time here. Dr. Rochelle‟s assistant Maeve Cooney has always been helpful especially
when planning for conferences or presentations. The time and energy she devotes to
training dogs for people with disabilities has always amazed me. Senior members that
have graduated (or will very soon) include; Eric Chen, Marcus Hilliard, Babatunde
Oyenekan, John McClees, Andrew Sexton and Ross Dugas. I would like to extend a
special thanks to Marcus, Andrew and Ross as all three were of great assistance in my
early years as an experimentalist. My contemporaries and junior members of the group
include Bob Tsai, Xi Chen, Jorge Plaza, David Van Wagener, Qing Xu, Sepidah Ziaii,
Stephanie Freeman, Fred Closmann, Thu Nguyen, Stuart Cohen, Alex Voice, Peter
Frailie and Chao Wang.
A number of people have become my friends throughout my graduate career that
I would like to acknowledge including Andrew, Bob, Ross and Stephanie from the
Rochelle group. Other ChemE‟s from my class include Kyle Friehauf, Steve Marek,
Justin Shofner, Daniel Carr, Adam Eckensair, Dave Simmons, Andy Heitsch, Reken
Patel, and Landry Khounlavong. I would also like to acknowledge my teammates on the
2009 graduate division intramural champion basketball team including Ross Dugas,
Landry Khounlavong, Joe Dekker, Brian McClosky, Hao Ju, David Kryscio, and Collin
Beal.
My family has always been supportive of my educational pursuits. It was never a
matter of if I went to college, but more a matter of when and where. From a young age
my parents encouraged me to do well in school and their faith in me and support will
vi
never be forgotten. I would like to thank my dad for giving me his inquisitive nature and
passing on the engineering gene to me. I have always enjoyed figuring out how things
work and imagining how to make them better, a trait that has not failed me in the field of
chemical engineering. I would like to thank my mom for all of her support. She has
always been good for a word of encouragement and never told me there was a limit on
what I could do. It was not just lip service that parents tell their kids, she actually
believed it, which made all the difference.
Mostly, I would like to thank my wife Niki. She was supportive when I wanted to
give up a good job at Merck and go back to graduate school. She took on the role of
primary breadwinner with a smile and willingly put our family plans on hold in order for
me to follow my heart. I will never forget her sacrifice, friendship and dedication
through these years. She also gave me my beautiful baby girl, Jocelyn, born on February
17, 2009. I cannot imagine how it could get any better, but I have said that before and
have been proven wrong time and time again.

vii
Thermal Degradation of Aqueous Amines Used for Carbon Dioxide
Capture

Publication No._____________

Jason Daniel Davis, Ph.D.
The University of Texas at Austin, 2009

Supervisor: Gary Rochelle

Aqueous amine solutions loaded with CO were degraded in stainless steel sealed
2
containers in forced convection ovens. Amine loss and degradation products were
measured as a function of time by cation chromatography (IC), HPLC, and IC/mass
spectrometry. A full kinetic model was developed for 15-40 wt% MEA
(monoethanolamine) with 0.2 – 0.5 mol CO /mol MEA at 100oC to 150oC. Experiments
2
using amines blended with MEA demonstrate that oxazolidone formation is the rate-
limiting step in the carbamate polymerization pathway. With 30 wt% MEA at 0.4 mol
CO /mol MEA and 120oC for 16 weeks there is a 29% loss of MEA with 13% as
2
hydroxyethylimidazolidone (HEIA), 9% as hydroxyethylethylenediamine (HEEDA), 4%
as the cyclic urea of the MEA trimer, 1-[2-[(2-hydroxyethyl)amino]ethyl]-2-
imidazolidone, 3% as the MEA trimer, 1-(2-hydroxyethyl)diethylenetriamine, and less
viii
than 1% as larger polymeric products. In the isothermal experiments, thermal
degradation was slightly more than first order with amine concentration and first order
with CO concentration with an activation energy of 33 kcal/mol. In a modeled isobaric
2
system, the amount of thermal degradation increased with stripper pressure, but
decreased with an increase in amine concentration and CO concentration due to a
2
reduction in reboiler temperature from the changing partial pressure of CO . Three-
2
fourths of thermal degradation in the stripper occurred in the reboiler due to the elevated
temperature and long residence time which offset the decrease in CO concentration
2
compared to the packing. The amount of degradation for other amines tested starting
with the least degraded include; cyclic amines with no side chains < long chain
alkanolamines < alkanolamines with steric hindrance < tertiary amines < MEA < straight
chain di- and triamines. Piperazine and morpholine had no measurable thermal
degradation under the conditions of this experiment and were the most resistant to
thermal degradation. Diethyelenetriamine and HEEDA had the largest amount of
degradation with over 90% loss at 135oC for 8 weeks.

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Table of Contents
List of Tables .........................................................................................................xv
List of Figures .................................................................................................... xviii
Chapter 1: Introduction ...........................................................................................1
1.1 Carbon Dioxide and the Environment .....................................................1
1.2 Carbon Dioxide Sinks and Sources..........................................................4
1.3 Carbon Dioxide Capture and Sequestration .............................................6
1.4 CO Capture by Amine Absorption/Stripping .........................................8
2
1.5 Solvent Management .............................................................................10
1.6 Previous Work .......................................................................................12
1.7 Research Objectives and Scope .............................................................13
Chapter 2: Literature Review ................................................................................16
2.1 Monoethanolamine ................................................................................16
2.1.1 Polderman ..................................................................................17
2.1.2 Yazvikova ..................................................................................19
2.1.3 Talzi ...........................................................................................20
2.1.4 Strazisar......................................................................................20
2.1.5 Laurance Reid Proceedings........................................................21
2.2 Diethanolamine ......................................................................................22
2.2.1 Polderman and Steel ..................................................................22
2.2.2 Meisen ........................................................................................25
2.2.3 Kim ............................................................................................28
2.3 Other Amines .........................................................................................31
2.3.1 Blake ..........................................................................................31
2.3.2 Kim ............................................................................................32
2.3.3 Meisen ........................................................................................33
2.3.4 Bedell .........................................................................................34
2.3.5 IFP ..............................................................................................35
x