Development and evaluation of aromatic polyamide-imide membranes for H₂S and CO₂ ...

295 Pages·2013·3.27 MB·English

DEVELOPMENT AND EVALUATION OF AROMATIC
POLYAMIDE-IMIDE MEMBRANES FOR H S AND CO
2 2
SEPARATIONS FROM NATURAL GAS

A Dissertation
Presented to
The Academic Faculty

by

Justin Vaughn

In Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy in the
School of Chemical and Biomolecular Engineering

Georgia Institute of Technology
May 2013

COPYRIGHT © JUSTIN TYLER VAUGHN 2013
DEVELOPMENT AND EVALUATION OF AROMATIC
POLYAMIDE-IMIDE MEMBRANES FOR CO AND H S
2 2
SEPARATIONS FROM NATURAL GAS

Approved by:

Dr. William Koros, Advisor Dr. Amyn Teja
School of Chemical and Biomolecular School of Chemical and Biomolecular
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. David Bucknall Dr. Krista Walton
School of Materials Science and School of Chemical and Biomolecular
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. Carson Meredith
School of Chemical and Biomolecular
Engineering
Georgia Institute of Technology
Date Approved: 20.February.2012
I have not failed. I have just found 10,000 ways that do not work.
-Thomas A. Edison
This dissertation is dedicated to my parents, Jeff and Kathi Vaughn. Without their loving
support, both emotionally and perhaps more important, financially, I would absolutely
without a doubt not be where I am today.
ACKNOWLEDGEMENTS

First and foremost, this project would not have been possible without the generous
funding provided by The King Abdullah University of Science and Technology Global Research
Partnership (KAUST-GRP), Award #KUS-I1-011-21.
Now I shall move on to the many memorable people who have made an impact on me
during my graduate school experience. Let me start by saying the last four years of my life have
been a roller coaster ride to say the least, filled with many highs as well as some lows. I have
learned and grown more, both as a chemical engineer and as a person, in the last 4 years than I
have in the last 23 years of my life. With that, a tremendous amount of gratitude is owed to my
advisor, Dr. William Koros. I am almost certain that I will never find another person more
dedicated to their craft than he is. His enthusiasm and tenacity for scientific discovery are second
to none, and I’m sure I’m not alone when saying it was inspiring at times. He was also willing to
take on a simple chemistry major such as myself, which definitely shocked me at the time.
Beyond just the field of membrane science, Dr. Koros has taught me that life is about “selling
yourself,” even if you believe that what you have to offer isn’t so exciting. Also, no matter how
busy he was, he was always willing to put in whatever amount of time and effort was necessary
for his students. For this, I will be forever grateful.
I would also like to thank my committee members, Dr. Bucknall, Dr. Meredith, Dr. Teja
and Dr. Walton for your valuable input and willingness to serve on my committee during the
important steps of my PhD education.
As cliché as it sounds, I could literally go on for pages thanking and talking about all of
the various people who have influenced me during my graduate school tenure. In an effort to save
from writing a novel, I will try to keep this concise, but in case you haven’t noticed from the rest
of this dissertation; my writing is probably anything but. I would like to start with Dr. JR Johnson
for putting up with me over the last four years, for consistently reminding me of my inferior
chemistry degree, for being jealous that he didn’t go to Ohio State, and in general having an
answer for every question or problem that I encountered. Along with JR, Dr. Oguz Karvan
designed and built the majority of the H S lab. A sincere amount of gratitude is owed to the two
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of you. Exceptional engineers the both of you are, but perhaps it was the general conversations—
both academic and non—that were the most memorable.
An order of thanks is owed to all Koros group members, past and present. Specifically,
Dr. Ryan Adams for “showing me the ropes” when I first joined the group; Dr. Jong Suk Lee for
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teaching me how to conquer the enigma that is the density gradient column as well as for being a
friend who was always up for coffee, cooking me tasty Korean food, and sharing a good laugh;
Dr. Dhaval Bhandari for solid professional and friendly advice, and finally Dr. Ryan Lively for
pleasant research as well as non-research related conversation, because let’s admit it, we don’t
think about research 100% of the time while we are in lab. You have all been good colleagues
and more importantly friends. I hope to maintain contact over the years.
My fellow classmates in the Koros group were also quite influential during my work.
Dr. Meha Rungta and Dr. Liren Xu, who although our research projects were very different, were
good citizens of the group who were able to share research ideas and humorous discussion. Dr.
Canghai Ma, who had the highly sought after privilege of sharing an office with me over the last
year, was a good office-mate who was willing to put up with my general office shenanigans. Dr.
Vinod Babu, who had the extra special privilege of sharing the same office space as me
throughout our entire Koros group tenure, was a good classmate, officemate, and friend. Thanks
for putting up with my antics, my terrible sense of humor and music choices, and generally
keeping me on the politically correct side of the spectrum. I would also like to mention and thank
Brian Kraftschick and Carine Kuete Achoundong, who worked alongside me on the H S projects,
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for sharing of data, general discussions about such wacky H S behavior, and for your willingness
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to sacrifice lab equipment during the latter parts of my work so that I could finish on time. Other
Koros group members who deserve mentioning are Stephen Burgess for DMA measurements as
well as just being a good person and group member, and Stephanie Li for being a friend, listener
to my general gripes and complaints about research, and for lending me batteries.
It would be remiss of me not to mention my regular Red Brick Brewery crew, Jonathon
‘T’ Rubin, Stephanie Didas and Ryan Clairemont, who were always up for Friday brewery tours.
Jonathon was also lucky enough to live in the same house as me for four years. Thanks for
providing me with many a late night and tremendously fruitful discussion, dinner leftovers, late
night Sunday trips to the grocery store, and various biking adventures. Josh Thompson, who is a
colleague as well as a friend, also deserves a ‘shout out.’ Let us not forget the times you Jonathon
and I had while living at 784 Penn Avenue. Those times are neither here nor there. And no, I’m
not forgetting you Erin Redmond. When research got the best of us, Erin was always up for
commiserating and debating whether graduate school was the right choice for us. Oh yea, Mr.
William Archie, thanks for Sunday dinners and being a good friend outside of Georgia Tech
throughout my time here in graduate school. I am thankful to have met all of you and know that I
have made friends for life.
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Last but certainly not least, an extraordinary amount of debt and gratitude is owed to
my parents, Jeff and Kathi Vaughn. Without your financial and emotional support, I can without a
doubt say I would not be here nor be the man that I am today. The two of you have sacrificed
more for me than I can ever hope to repay. I could not have asked for better parents, and hope that
one day I can repay even a shred of it back to you. And how could I forget my brother, Josh
Vaughn, who probably understands me more than anyone on this planet. Thanks for the fun and
memorable summer trips while I was here in Atlanta.
Hopefully I’ve mentioned everyone, and I am sincerely sorry if I forgot you. It has been
a wild four years and I thoroughly look forward to what life will bring me next. Godspeed, and
bring it on real-world!

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TABLE OF CONTENTS

ACKNOWLEDGEMENTS ............................................................................................... iv
LIST OF TABLES ........................................................................................................... xiii
LIST OF FIGURES ......................................................................................................... xvi
SUMMARY ................................................................................................................... xxiii

CHAPTER 1: INTRODUCTION AND MOTIVATION………………………………... 1
1.1. Natural Gas Production .....................................................................................1
1.2. Membrane Separations……………………………………………………..... 5
1.3. H S Removal from Natural Gas………………………………….………...... 8
2
1.4. Research Objectives ........................................................................................12
1.5. Dissertation overview .....................................................................................14
1.6. References .......................................................................................................15
CHAPTER 2: BACKGROUND AND THEORY .............................................................17
2.1. Polymeric Membranes for Gas Separations…………………………………17
2.2. Gas Transport through Non-porous Media .....................................................19
2.2.1. General Transport Theory……………………………………………. 19
2.2.2. Transport in Rubber Polymers ...............................................................25
2.2.3. Transport in Glassy Polymers ................................................................28
2.2.4. Temperature Dependence of Transport Parameters ...............................33
2.3. Non-Ideal Transport Effects ...........................................................................35
2.3.1. Plasticization ..........................................................................................35
2.3.2. Competitive Sorption .............................................................................37
2.4. Challenges Associated with the Simultaneous Removal of CO and H S….. 38
2 2
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2.5. Methods for Controlling Plasticization………………………………………44
2.6. References…………………………………………………………………... 49
CHAPTER 3: MATERIALS AND METHODS ...............................................................53
3.1. Materials .........................................................................................................53
3.1.1. Glassy Polymers.....................................................................................53
3.1.2. Rubbery Polymers ..................................................................................56
3.2. Membrane Fabrication ....................................................................................56
3.2.1. Formation of Dense Film Membranes ...................................................56
3.2.2. Membrane Masking ...............................................................................59
3.3. Membrane Characterization Techniques ........................................................61
3.3.1. Permeation Analysis ..............................................................................61
3.3.1.1. Permeation Equipment ................................................................. 61
3.3.1.2. Design Considerations for H S Handling .....................................62
2
3.3.1.3. Pure Gas Permeation Analysis ......................................................64
3.3.1.4. Mixed Gas Permeation ..................................................................69
3.3.2. Gas Sorption...........................................................................................71
3.3.3. Thermal Analysis ...................................................................................73
3.3.3.1. Thermal Gravimetric Analysis (TGA) ..........................................73
3.3.3.2. Differential Scanning Calorimetry (DSC) ................................... 75
3.3.4. FTIR-ATR Spectroscopy .......................................................................75
3.3.5. UV-Vis/Microfluorescence Spectroscopy .............................................75
3.3.6. X-Ray Diffraction ..................................................................................76
3.3.7. Bulk Density ..........................................................................................76
3.3.8. Gel Permeation Chromatography (GPC) .............................................. 77
3.4. References .......................................................................................................77
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CHAPTER 4: EFFECT OF THERMAL ANNEALING ON THE
BASE STRUCTURE: 6F-PAI-1........................................................................................78
4.1. Annealing Protocol .........................................................................................78
4.2. Pure Gas Plasticization Analysis ....................................................................81
4.3. Characterization of the Polymer Physical Structure .......................................85
4.3.1. Microfluorescence Spectroscopy…………………………………….. 86
4.3.1.1. Fluorescence Excitation ................................................................87
4.3.1.2. Fluorescence Emission ..................................................................89
4.3.2. X-Ray Diffraction Analysis ....................................................................90
4.4. Characterization of Single Gas Transport Properties ......................................98
4.4.1. Single Gas Permeation ........................................................................... 98
4.4.2. Single Gas Sorption .................................................................................99
4.4.3. Single Gas Diffusion .............................................................................104
4.5. Mixed Gas Permeation .................................................................................108
4.5.1. 50/50 CO /CH4 .....................................................................................108
2
4.5.2. Effect of Toluene Exposure ...................................................................110
4.5.3. Effect of H S Exposure .........................................................................113
2
4.6. Comparison of 6F-PAI-1 to Upper-Bound ...................................................117
4.7. Conclusions ..................................................................................................120
4.8. References ....................................................................................................121

CHAPTER 5: EFFECT OF THE AMIDE BOND DIAMINE STRUCTURE ON THE
CO , CH , AND H S TRANSPORT PROPERTIES .......................................................124
2 4 2

5.1. Introduction ..................................................................................................124
5.2. Material Development ..................................................................................127
5.3. Physical Structure Characterization .............................................................129
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