Hydrothermal Catalytic Deoxygenation of Fatty Acids and Upgrading Algae Biocrude
Total Page：16
File Type：pdf, Size：1020Kb
Hydrothermal Catalytic Deoxygenation of Fatty Acids and Upgrading Algae Biocrude by Thomas M. Yeh A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemical Engineering) in the University of Michigan 2015 Doctoral Committee: Professor Suljo Linic, Co-chair Professor Phillip E. Savage, Co-chair Professor Adam J. Matzger Professor Levi T. Thompson © Thomas M. Yeh All rights reserved. 2015 To my family and friends. ii ACKNOWLEDGMENTS I thank my committee members, Phil, Suljo, and Adam for their guidance and support during my time at Michigan. Each member has asked many thought pro- voking questions that have resulted in higher quality research. Their contributions have been instrumental to my success. My wife, Karen, has provided unending support throughout this time. She has been with me every step of the way, and she has never asked me the most dreaded question of the PhD student – “How’s your research going?”. My parents helped in the best way parents can – with free food. The skills my parents taught me through maintaining apartments has been used repeatedly in the lab through reactor construction and general equipment maintenance. Professional statistical analysis, career advice, and general support was al- ways a phone call away. My in-laws support has consistently far exceeded expec- tations over the years. The Savage and Linic group members have provided valuable feedback through discussions and thought provoking questions during group presentations. My friends provided much needed escapes from research. Leonid Pavlovsky introduced me to the art of beer brewing. As a result, I have slowly transformed into a beer snob, and Michelle Przybylek held a birthday party for me every year. Matt Morabito, Julia Faeth, Lilian Hsiao, Chad Huelsman, Ryan Franck, and Luke Griffith played Dungeons & Dragons with me and fulfilled my innate desire to nerd-out. Peter Valdez and I went on many outings to the shooting range, and he offered me training in the art of tact. Youngri Kim provided many rides to the airport and helped fulfill my love of being cheap and not paying for airport parking. Jenn Jocz was a good tennis partner, and she was able to put up with being in my office and not be offended. Yang Guo and Donghai Xu taught me Chinese and corrected my accent. Because of Yang, I also ate more bacon in one year than I have in my entire life thus far. Lastly, I am grateful for the staff. Kelly Raickovich, Susan Hamlin, Shelley Fellers, Pam Bogdanski, and Laura Bracken have provided a lot of administrative support. Kelly provided copious amounts of free food and literally provided the energy for a lot of this work. iii Preface All work presented was performed at the University of Michi- gan. This work contains both published and unpublished work that is the original work of the author, Thomas Yeh. Portions of Chapter2 are published as a review paper. Some of Chapter4 and most of Chapter5 has been published, but Chapter5 has been modified to include unpublished material. Finally, Chapter6, has been submitted for publication and is under review at the time of this writing. iv TABLE OF CONTENTS Dedication .......................................... ii Acknowledgments ..................................... iii Preface ............................................. iv List of Figures ........................................ viii List of Tables ......................................... xi List of Appendices ..................................... xiii List of Abbreviations ................................... xiv Abstract ............................................ xv Chapter 1 Introduction ........................................ 1 1.1 Background and Motivation.........................1 1.2 Biomass......................................3 1.2.1 First and Second Generation Biofuels..............4 1.2.2 Third Generation – Algae......................5 1.3 High temperature water...........................6 1.3.1 Supercritical Water..........................7 2 Literature Review .................................... 9 2.1 Hydrothermal Liquefaction Oil.......................9 2.2 Deoxygenation of Fatty Acids........................ 12 2.2.1 Decarboxylation of Saturated Fatty Acids........... 13 2.2.2 Decarboxylation of Unsaturated Fatty Acids.......... 17 2.3 Upgrading of Biocrude from Hydrothermal Liquefaction and Model Compounds................................... 21 2.3.1 Catalytic Hydrothermal Deoxygenation............ 21 2.3.2 Catalytic Hydrothermal Denitrogenation............ 24 2.3.3 Catalytic Hydrothermal Desulfurization............ 26 2.3.4 Hydrothermal Catalytic Upgrading of Real Biocrude Oils. 27 2.4 Hydrothermal Catalyst Stability...................... 31 v 3 Research Objectives ................................... 36 3.1 Objectives.................................... 36 4 Experimental Methods ................................. 38 4.1 Materials..................................... 38 4.2 Catalyst Synthesis............................... 39 4.3 Reactor Procedures.............................. 40 4.3.1 High Pressure Flow Reactor for Catalyst Deactivation Studies 40 4.3.2 Batch Reactions for Platinum Tin Studies with Unsaturated Fatty Acids............................... 42 4.3.3 Algal Biocrude Upgrading Studies................ 43 4.4 Analytical Chemistry............................. 45 4.4.1 Gas Chromatography........................ 45 4.4.2 Infrared Spectroscopy........................ 47 4.4.3 Catalyst Characterization...................... 48 5 Pt/C Deactivation in the Decarboxylation of Butyric Acid .......... 49 5.1 Introduction................................... 49 5.2 Reaction Products............................... 51 5.3 Deactivation Kinetics............................. 55 5.4 Cause of Deactivation............................. 62 5.5 Conclusions................................... 71 5.6 Acknowledgements.............................. 72 6 PtSn Catalysts for Decarboxylation of Unsaturated Fatty Acids ....... 73 6.1 PtM alloy catalysts............................... 73 6.2 Carbon Balances................................ 75 6.3 Reaction Products............................... 76 6.4 Catalyst Characterization........................... 79 6.5 Source of Hydrogen.............................. 82 6.5.1 From H2O Reacting With Pt/C.................. 82 6.5.2 From Reactant Alone........................ 83 6.5.3 From Water Alone.......................... 87 6.5.4 From Both H2O and Reactant................... 87 6.6 Conclusion.................................... 89 6.7 Acknowledgements.............................. 89 7 Activity Screening of Potential Hydrothermally Stable Catalysts ..... 90 7.1 Catalyst Selection............................... 90 7.1.1 Metal Catalyst............................. 91 7.1.2 Catalyst supports........................... 91 7.2 Results and Discussion............................ 95 7.2.1 Biocrude Analysis.......................... 97 7.2.2 Upgraded Bio-oil........................... 99 7.2.3 Limitations of the Experimental Methods............ 112 vi 7.3 Conclusion.................................... 113 7.4 Acknowledgements.............................. 115 8 Conclusions, Future Work, and Outlook ..................... 116 Appendices .......................................... 121 Bibliography ......................................... 179 vii LIST OF FIGURES 1.1 Total US energy delivered by sector from 1980 – 2040............2 1.2 Transportation fuel use by type for North America and Asia Pacific (Millions of oil-equivalent barrels per day)..................3 1.3 Physical properties of water at 24 MPa with respect to temperature...7 2.1 Pt/C selectivity to n-heptadecane for stearic, oleic, and linoleic feeds in water.......................................... 20 2.2 Total ion chromatograms from crude bio-oil (top) and upgraded prod- uct oil (bottom) obtained from SCW treatment with Pt/C, H2 ....... 29 2.3 BET surface area of untreated 1 % Pt/Al2O3 and after 10 h treatment at 225 C in different solutions............................ 34 4.1 Flow reactor schematic............................... 41 5.1 Butyric acid decarboxylation........................... 51 5.2 Carbon recovery in gas and liquid phase reactor effluent from hydrother- mal treatment of 0.2 M butyric acid over Pt/C at 350 C with W/n = 300 mg min/mL...................................... 52 5.3 H/C and CO2/C3H8 ratios from hydrothermal treatment of 0.2 M bu- tyric acid over Pt/C at 350 C with W/n = 300 mg min/mL......... 53 5.4 Molar ratios of lower alkanes to propane for hydrothermal treatment of 0.2 M butyric acid over Pt/C at 350 C with W/n = 300 mg min/mL.. 56 5.5 Flash column modeled as two stirred tanks with exchange between mL mL 1 tanks. V1 V2 200mL, n0 n1 5 min , n2 n3 3 min , kd 0.06h ..... 59 5.6 Deactivation data with model incorporating mixing in flash column... 60 5.7 Variation of first-order rate constant with time on stream for hydrother- mal decarboxylation of 0.2 M butyric acid feed over Pt/C with at W/n = 300 mg min/mL at room temperature with a reaction temperature of 350 C.......................................... 62 5.8 XRD spectra of fresh and used (24 h time on stream at 350 C) Pt/C catalysts........................................ 64 5.9 TEM images of Pt/C................................ 64 5.10 DRIFTS spectra for TiO2 and Pt/TiO2 catalysts. From top to bottom: P25 titania as received, unused Pt/TiO2, Pt/TiO2 after 24 h time on stream at 350 C with 0.2 M butyric acid feed with W/n = 300