Growth of Polycyclic Aromatic Hydrocarbons during the Supercritical Pyrolysis of n-Decane

317 Pages·2017·20.07 MB·English

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LSU Doctoral Dissertations Graduate School
2016
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Subramanian Venkateswaran Kalpathy
Louisiana State University and Agricultural and Mechanical College
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Kalpathy, Subramanian Venkateswaran, "Growth of Polycyclic Aromatic Hydrocarbons during the
Supercritical Pyrolysis of n-Decane" (2016). LSU Doctoral Dissertations. 3725.
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GROWTH OF POLYCYCLIC AROMATIC HYDROCARBONS DURING THE
SUPERCRITICAL PYROLYSIS OF n-DECANE

A Dissertation
Submitted to the Graduate Faculty of the
Louisiana State University and
Agricultural and Mechanical College
in partial fulfillment of the
requirements for the degree of
Doctor of Philosophy

in

The Gordon A. and Mary Cain Department of Chemical Engineering

by
Subramanian Venkateswaran Kalpathy
B.E., University of Pune, India, 2009
May 2016
Dedicated to my late grandmother Vijayam S. Nathan

ii
Acknowledgements
First and foremost I would like to thank the most important person in this endeavor, my
Ph.D. advisor, Prof. Mary J. Wornat, without whom this thesis would not have been possible.
She believed in me at times when I did not believe in myself. I am forever grateful for her
constant encouragement and passing on her knowledge not only about science but also about life
in general. Throughout my journey as a graduate student and as a researcher she has been a
constant source of inspiration. One could not have asked for a better advisor.
Next, I would like to thank the other members on my thesis committee, Dr. Francisco R.
Hung, Dr. James J. Spivey, Dr. Michael L. Cherry for their valuable time and inputs. I gratefully
acknowledge the Air Force Office of Scientific Research for providing funding for this work. For
providing PAH reference standards and UV spectra, which is extremely essential for this work, I
would like to thank the following: Dr. Arthur Lafleur and Ms. Elaine Plummer, of the
Massachusetts Institute of Technology; Dr. John Fetzer, of FETZPAHS; Dr. Hilan Kaplan, of
Boston College; Dr. Markus Braun and Prof. Maximilian Zander, of RÜTGERS Basic Aromatics
GmbH; Dr. Michael J. Krische, University of Texas; Prof. Bongsup Cho, University of Rhode
Island; Prof. Thomas E. Prisinzano and Mr. Benjamin Neuenswander, University of Kansas;
Prof. Yasushi Nishihara and Prof. Masayuki Iwasaki, Okayama University; Dr. Qingsu Xia,
National Center for Toxicological Research; Dr. Yao-Ting Wu, National Cheng Kung
University; Dr. Dianne Poster, of National Institute of Standards and Technology; and Ms. Leslie
Karlin, of the Chemical Carcinogen Standards Reference Repository, National Cancer Institute.
A mentor for whom I am extremely grateful is Dr. Nimesh Poddar. He has not only been my
mentor but also like my elder brother in this research group. He has always been there for me at
times when I needed him the most. He has provided me with numerous valuable inputs in my
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dissertation. I will always be grateful to him for sharing his knowledge and expertise of UV
spectra. I consider it to be my privilege to have worked with him in a lot of challenging
situations. I would like to thank Dr. Sean Bagley who taught me how to perform experiments
and the extremely complex product analyses. He has been a very encouraging and supportive
mentor. I would also like to thank Dr. Franz Ehrenhauser for the motivation he gave me during
my early years as a graduate student and training me to use the LC-MS instrument. My sincere
thanks to Mr. Matthew Skapura for his assistance in organizing the lab. His help made a lot of
difference especially during time-crunching situations. I would also like to thank Ms. Catherine
Poddar, Ms. Eva Caspary, and Ms. Elizabeth Hurst for their help during my time in the lab.
I am thankful to Joe, Darla, Danny, and Rachel—the workshop and administrative staff at the
Department of Chemical Engineering—for their help on countless occasions. I would also like
to thank the LSU Graduate School for providing travel support through the Coates Travel awards
for conference travels to Beijing, Munster, Warsaw, Corvallis, and San Francisco to present my
research. My sincere thanks to the Combustion Institute for providing travel support for
presenting my work at the 35th International Symposium on Combustion held in San Francisco.
I would like to thank my dear friends Saroj, Nidhi, Brajesh, Anvita, Anuja, Prathvind, Richie,
Ahalya, Kalindi, Sarthak, Rahul, Dipti, Kaushik, Kundan, Jesil, Sneha, Manasi, and Vinay, who
helped my stay cheerful during this long journey by not allowing me to feel homesick. I am
thankful to Dr. Sharanya Prasad, one of my oldest friends since my childhood, for all the
memorable conversations we had about each of our Ph.D. journey and her valuable advice.
This acknowledgement would not be complete without mentioning Divya Mohan. I cannot
thank her enough for her patience, for believing in me, supporting me at the toughest moments,
motivating me to constantly push my limits to achieve my goals, and for the love she has given
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me. I look forward to a lifelong journey filled with love and happiness with her. I would also like
to thank Mohan Subramanian, Revathi Mohan, and Deepa Mohan for their constant prayers for
my success.
I would like to thank my little sister, Padma, for her loving care, for standing by me
throughout my life, and being the wonderful sister that she is. I would also like to thank my
uncles and aunts, Venkatram Krishnan, TRS Subramanian, Shilpa Krishnan, and Charu
Subramanian for their constant support and making sure that my stay in the United States was
comfortable.
Finally, I am forever grateful to my parents, K. V. Subramanian and Ananthalakshmi
Subramanian, for believing in me, encouraging me to take this path and for being my role
models.

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Table of Contents
Acknowledgements ........................................................................................................................ iii
List of Tables ............................................................................................................................... viii
List of Figures ................................................................................................................................ ix
Abstract ...................................................................................................................................... xxix
Chapter 1. Introduction .................................................................................................................. 1
1.1 Background and Motivation ...................................................................................... 1
1.2 Purpose of Research................................................................................................. 10
1.3 Structure of the Dissertation .................................................................................... 12
Chapter 2. Experimental Equipment and Analysis Techniques ................................................... 15
2.1 Introduction .............................................................................................................. 15
2.2 Supercritical Fuel Pyrolysis Reactor System ........................................................... 15
2.3 Product Analysis ...................................................................................................... 18
2.3.1 Gas-Phase Product Analysis ........................................................................... 19
2.3.2 Liquid-Phase Product Analysis ....................................................................... 20
2.3.2.1 Analysis of Aliphatic and One-Ring Aromatic Products .................. 20
2.3.2.2 Analysis of Two-Ring Aromatic Products ........................................ 25
2.3.2.3 Analysis of 2- to 10-Ring PAH Products .......................................... 26
2.4 Concluding Remarks................................................................................................ 35
Chapter 3. The Effects of Temperature on the Yields of the Major Aliphatic and Aromatic
Products of Supercritical n-Decane Pyrolysis ............................................................................... 36
3.1 Introduction ............................................................................................................... 36
3.2 Experimental Equipment and Procedures ................................................................. 38
3.3 Results and Discussion ............................................................................................. 40
3.3.1 Aliphatic Products of Supercritical n-Decane Pyrolysis .................................. 41
3.3.2 Aromatic Products of Supercritical n-Decane Pyrolysis ................................. 45
3.4 Summary and Conclusions ....................................................................................... 62
Chapter 4. The Effects of Pressure on the Yields of the Major Aliphatic and Aromatic Products
of Supercritical n-Decane Pyrolysis.............................................................................................. 65
4.1 Introduction ............................................................................................................... 65
4.2 Experimental Equipment and Procedures ................................................................. 68
4.3 Results and Discussion ............................................................................................. 70
4.3.1 Aliphatic Products of Supercritical n-Decane Pyrolysis .................................. 71
4.3.2 Aromatic Products of Supercritical n-Decane Pyrolysis ................................. 73
4.4 Summary and Conclusions ....................................................................................... 89

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Chapter 5. Reaction Pathways for the Growth of Polycyclic Aromatic Hydrocarbons during the
Supercritical Pyrolysis of n-Decane, as Determined from Doping Experiments with 1- and 2-
Methylnaphthalene ........................................................................................................................ 91
5.1 Introduction ............................................................................................................... 91
5.2 Experimental Equipment and Procedures ................................................................. 93
5.3 Results and Discussion .............................................................................................. 94
5.4 Conclusion ............................................................................................................... 113
Chapter 6. Growth Reactions of Polycyclic Aromatic Hydrocarbons during the Supercritical
Pyrolysis of n-Decane, as Determined from Doping Experiments with 1-Methylphenanthrene
and Fluorene................................................................................................................................ 115
6.1 Introduction ............................................................................................................. 115
6.2 Experimental Equipment and Procedures ............................................................... 116
6.3 Results and Discussion ............................................................................................ 118
6.4 Conclusion ............................................................................................................... 136
Chapter 7. Conclusions and Recommendations for Future Work ............................................. 138
7.1 Summary ................................................................................................................. 138
7.2 Recommendations for Future Work ........................................................................ 147
References ................................................................................................................................... 149
Appendix A Supporting Information for Chapter 2 ................................................................... 155
Appendix B Supporting Information for Chapter 3 ................................................................... 161
Appendix C Supporting Information for Chapter 4 ................................................................... 195
Appendix D Supporting Information for Chapter 5 ................................................................... 231
Appendix E Supporting Information for Chapter 6 ................................................................... 254
Appendix F Letters of Permission ............................................................................................. 278
Vita .............................................................................................................................................. 286

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List of Tables
1.1. Critical properties of n-decane and other jet fuels1 ............................................................ 7
2.1. Contents of the 15 Normal-Phase HPLC Fractions of an n-Decane Product Mixture ..... 24
2.2. Reversed-phase HPLC solvent methods for the analysis of liquid-phase PAH products of
supercritical n-decane pyrolysis in Fractions 2 through Fractions 1540,53,54,61 ................. 29
6.1. Reactions of 1-naphthylmethyl as determined from 1-methylnaphthalene-doped n-decane
pyrolysis experiments79 .................................................................................................. 130
A1. GC retention times and Response factors for C -C hydrocarbons ................................ 155
1 6
A2. GC retention times and response factors for n-alkanes, one-, and two-ring aromatics .. 156
A3. Surrogates compounds for GC calibration ...................................................................... 157
A4. HPLC elution times and response factors for polycyclic aromatic hydrocarbons .......... 158

A5. Surrogates compounds for HPLC calibration ................................................................. 159

B1. Global first-order kinetic rate parameters E and ln A , for aromatic products of
app app
supercritical n-decane pyrolysis at 94.6 atm ................................................................... 161

C1. Global first-order kinetic rate parameters ΔV≠ and ln A , for aromatic products of
p
supercritical n-decane pyrolysis at 570 °C ..................................................................... 195
D1. Aromatic products of supercritical n-decane pyrolysis .................................................. 231
E1. Quantified aromatic products of supercritical n-decane pyrolysis ................................. 254

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List of Figures
1.1. Molecular structure and bond-dissociation energies46 for model fuel n-decane ................. 3
1.2.   Favored  4-,  6-,  and  8-ring  benzenoid  PAH  products  of  supercritical  n-decane  pyrolysis...8

1.3. Molecular structures and bond-dissociation energies46,58 for model fuels toluene and 1-
methylnaphthalene .............................................................................................................. 9

1.4. Formation of C H PAH products of supercritical toluene pyrolysis41,50 (top two rows)
14 10
and of C H PAH products of supercritical 1-methylnaphthalene pyrolysis30 (bottom
22 14
two rows). These reactions exemplify Mechanism I, arylmethyl / methylaromatic
addition ............................................................................................................................. 10

1.5. Formation of C H and C H PAH products of supercritical toluene pyrolysis41 (top
13 10 21 14
two rows) and C H PAH products of supercritical 1-methylnaphthalene pyrolysis30
21 14
(bottom two rows). These reactions exemplify Mechanism II, arylmethyl / aromatic
addition. The red structure corresponds to toluene pyrolysis product of Mechanism I in
Figure 1.4 .......................................................................................................................... 10

1.6.   Molecular  structures  of  dopants,  2-methylnaphthalene  and  1-methynaphthalene,  used  in  
the  supercritical  n-decane  pyrolysis  experiments ............................................................. 13

1.7.   Molecular   structures   of   dopants,   fluorene   and   1-methylphenanthrene,   used   in   the  
supercritical  n-decane  pyrolysis  experiments ................................................................... 14
2.1. Schematic of the supercritical fuel pyrolysis reactor system ............................................ 16
2.2. Analysis scheme for liquid-phase products of supercritical pyrolysis of n-decane.  Note
that there are four analysis or fractionation/analysis sequences. An exit stream marked
“lighter   part”   or   “heavier   part”   from   an   HPLC/FC   fractionation   step   in   one   of   the  
sequences contains material whose analysis is covered in one of the other analysis
sequences, tailored to that material ................................................................................... 21
2.3. Comparisons of the UV spectra of n-decane pyrolysis products (solid lines) to reference
spectra (dashed lines). Comparisons are shown for the products identified as (a)
benzo[a]pyrene, (b) 8-methylbenzo[a]pyrene, (c) benzo[pqr]naphtho[8,1,2-bcd]perylene,
and (d) a methylated benzo[pqr]naphtho[8,1,2-bcd]perylene. The reference spectra in (a)-
(d) are from reference standards. The mass spectrum for each product is displayed as an
inset to the respective figure. In (d) note that relative to the UV spectrum of
benzo[pqr]naphtho[8,1,2-bcd]perylene the UV spectrum of methylated
benzo[pqr]naphtho[8,1,2-bcd]perylene is shifted by 2.5 nm to higher wavelengths ....... 31
2.4. Reversed-phase HPLC chromatogram of Fraction 6 of the products of n-decane pyrolysis
at 570 °C and 94.6 atm. This fraction primarily contains the C H benzopyrenes and
20 12
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