GAS-LIQUID PHASE EQUILIBRIA IN THE HELIUM-CARBON TETRAFLUORIDE AND HELIUM-CHLOROTRIFLUOROMETHANE SYSTEMS AT LOW TEMPERATURES AND 20-120 ATMOSPHERES A THESIS Presented to The Faculty of the Graduate Division by Yo Kil Yoon In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy In the School of Chemical Engineering Georgia Institute of Technology November, 1971 GAS-liQUID PHASE EQUILIBRIA IN THE HELIUM-CARBON TETRAFLUORIDE AND HELIUM-CHLOROTRIFLUOROMETHANE SYSTEMS AT LOW TEMPERATURES AND 20-120 AT1?0SPHERES Approved; Date approved by Chairman; 1^^- H ^ll I In presenting the dissertation as a partial fulfillment of the requirements for an advanced degree from the Georgia Institute of Technology, I agree that the Library of the Institute shall make it available for inspection and circulation in accordance with its regulations governing materials of this type. I agree that permission to copy from, or to publish from, this dissertation may be granted by the professor under whose direction it was written, or, in his absence, by the Dean of the Graduate Division when such copying or publication is solely for scholarly purposes and does not involve potential financial gain. It is under­ stood that any copying from, or publication of, this dis­ sertation which involves potential financial gain will not be allowed without written permission. 7/25/68 li DEDICATION To the memory of my mother and father ili ACKNOWLEDGMENTS It is my sincere wish to express a particular grati- tute to Dr. W. T, Ziegler, my thesis advisor, for his en­ couragement, suggestions and fruitful discussions during this research. Especially, his broad and profound knowledge of thermodynamics was of great help in carrying out all theoretical treatments of this work. His continuous teaching and suggestions for the experimental techniques before and during the experimental work were also very helpful in deve­ loping attitutes necessary for an experimenter. I wish to thank to Dr. B. S. Kirk, who built the phase equilibrium apparatus used in this work. I also extend my appreciation to Dr. J. D. Garber, who assisted me in learning the actual operation of the apparatus and whose several com­ puter programs were of great help in making theoretical cal­ culations . Dr. R. A. Pierotti and Dr. J. D. Muzzy are acknowledged for serving on the Thesis Reading Committee. I am also indebted to the School of Chemical Engi** neering for the financial support through teaching assistan- ships during 1969-1971. Thanks are due the Rich Electronic Computer Center for the use of their facilities. My appreciation is also given to Korean Military Academy for allowing me a leave of absence to come the iv United States and accomplish this research. Finally, I am extremely grateful to my wife, Buhm Jin, for her endurance, encouragement and continuous love which have made the present work a reality. Particularly, her help with typing the final copy of this thesis is gratefully acknowledged. TABLE OF CONTENTS Page ACKNOWLEDGMENTS iil LIST OF TABLES viii LIST OF FIGURES x NOMENCLATURE , xlii SUMMARY XX Chapter I. INTRODUCTION 1 II. EXPERIMENTAL APPARATUS 8 Description of Apparatus Experimental Procedure III. EXPERIMENTAL RESULTS AND DISCUSSION .... 17 Introduction Experimental Results Discussion of Results IV. CALCULATION OF ENHANCEMENT FACTORS 33 Introduction Equations of State Considered Virial Equation of State Calculation of Virial Coefficients Benedict-Webb-Rubin Equation of State V. COMPARISON OF PREDICTED AND EXPERIMENTAL GAS PHASE EQUILIBRIUM DATA 63 Interaction Second Virial Coefficient Enhancement Factor VI. COMPARISON OF PREDICTED AND EXPERIMENTAL LIQUID PHASE EQUILIBRIUM DATA 96 Experimental Henry's Law Constant and Par­ tial Molar Volume at Infinite Dilution vi TABLE OF CONTENTS (Continued) Page Theoretical Prediction of Henry's Law Constant and Partial Molar Volume at Infinite Dilution VII. CONCLUSIONS AND RECOMMENDATIONS 129 Conclusions Recommendations APPENDICES 137 A. TEMPERATURE SCALE USED AND CORRECTIONS FOR PRESSURE GAUGES 138 B. HELIUM-PROPYLENE SYSTEM MEASUREMENTS .... 140 C. EXTRACTION OF KIHARA POTENTIAL PARA­ METERS FROM EXPERIMENTAL SECOND VIRIAL COEFFICIENT DATA 1^3 D. COMMENTS ON THE CALCULATION OF THE REDUCED VIRIAL COEFFICIENTS BASED ON THE LENNARD-JONES POTENTIAL lA9 E. CALIBRATION OF GAS CHROMATOGRAPHS 154 General Analysis of Carbon Tetrafluoride in Helium Analysis of Chlorotr1£luoromethane in Helium Analysis of Helium in Carbon Tetrafluoride and chlorotrifluoromethane F. SUMMARY OF EXPERIMENTAL PHASE EQUILIBRIUM DATA FOR THE HELIUM-CARBON TETRAFLUORIDE AND HELIUM-CHLOROTRIFLUOROMETHANE SYSTEMS. 163 G. SMOOTHED EXPERIMENTAL AND THEORETICAL EN­ HANCEMENT FACTORS, AND SMOOTHED EXPERIMENTAL SOLUBILITY OF HELIUM 181 H. SELECTION OF PHYSICAL PROPERTY DATA FOR PURE COMPONENTS 186 Helium Carbon Tetrafluoride Chlorotrifluoromethane vii TABLE OF CONTENTS (Concluded) page I. PURITY OF GASES USED 206 BIBLIOGRAPHY 207 VITA 219 viii LIST OF TABLES Table Page 1, Bi2 for the Helium-Carbon Tetrafluoride System 70 2, Bi2 for the Helium-Chlorotrifluoromethane System •••• 72 3, Values of Kj2 fo^^ the Helium-Carbon Tetrafluoride and Helium-Chlorotri- fluoromethane Systems 79 4, H2 and V^ for the Helium-Carbon Tetrafluoride System 104 00 —00 5, Hj and V2 for the Helium-Chlorotri- 106 fluoromethane System 6. Boiling Point Data for Pure Components . • • . 117 7. Parameters for the Method of Snider and Herrington 117 8. Molar Volumes of the Pure Liquid Components at Saturation •• •... 125 9. Comparison of Predicted and Experimental 00 ' —00 ^ 10/: H2 and V^ for Some Binary Systems. ...... IZb 10. Comparison of B*L(T*)»S and C^L(T*)»S Calculated Using Kirk*s b^^^'s and Kihara's c^^^'s. Respectively ,c-| 11. Operating Conditions of Chromatographs . • • 162 12. Experimental Gas and Liquid Phase Equilibrium Compositions in the Helium- Carbon Tetraf luoride System 165 13. Experimental Gas and Liquid Phase Equilibrium Compositions in the Helium- Chlorotrif luoromethane System 172 ix LIST OF TABLES (Continued) Table Page 14. Smoothed Experimental and Theoretical Enhancement Factors of Carbon Tetra- fluoride in Helium, and the Smoothed Experimental Solubility of Helium in Liquid Carbon Tetrafluoride 182 15. Smoothed Experimental and Theoretical Enhancement Factors of Chlorotrifluoro- methane in Helium, and the Smoothed Experimental Solubility of Helium in Liquid Chlorotrifluoromethane .... 184 16. Input Parameters for the Calculation of Third Virial Coefficients Using the Method of Chueh and Prausnitz .... 189 17. Intermolecular Potential Parameters and BWR Parameters 190 18. Compressibility Factors of Saturated Liquid Estimated Using the Generalized Correlation Given by Chueh and Prausnitz and the Critical Constants 191 19. Vapor Pressures of Carbon Tetrafluoride and Chlorotrifluoromethane 200 LIST OF FIGURES Figure Page 1. Schematic Diagram of Phase Equilibrium Apparatus . • 10 2. Experimental Enhancement Factors of Carbon Tetrafluoride in Helium at 106.01, 117.33, 132.18, and 147.10 K. 19 3. Experimental Enhancement Factors of Carbon Tetrafluoride in Helium at 162.03 and 173.02 K 20 A. Experimental Enhancement Factors of Carbon Tetrafluoride in Helium along Isobars 21 5. Experimental Solubility of Helium in Liquid Carbon Tetrafluoride ..... 22 6. Experimental Enhancement Factors of Chlorotrifluoromethane in Helium at 145.21, 163.01, and 180.02 K 23 7. Experimental Enhancement Factors of Chlorotrifluoromethane in Helium at 196.01, 211.06, 221.27, and 231.08 K. 24 8. Experimental Enhancement Factors of Chlorotrifluoromethane in Helium along Isobars 25 9. Experimental Solubility of Helium in Liquid Chlorotrifluoromethane .... 26 10. Predicted and Experimental Bjj fo^^ the Helium-Carbon Tetrafluoride System at Temperatures between 106 to 173 K . 67 11. Predicted and Experimental B^^ for the Helium-Carbon Tetrafluoride System at Temperatures between 106 to 773 K . 68 12. Predicted and Experimental B12 for the Helium-Chlorotrifluoromethane System. 71 XI LIST OF FIGURES (Continued) Figure Page 13. Theoretical and Experimental Enhancement Factors in the Helium-Carbon Tetrafluo- ride System at 106.01 K 81 14. Theoretical and Experimental Enhancement Factors in the Helium-Carbon Tetrafluo- ride System at 117.33 K 82 15. Theoretical and Experimental Enhancement Factors in the Helium-Carbon Tetrafluo- ride System at 147.10 K 83 16. Theoretical and Experimental Enhancement Factors in the Helium-Carbon Tetrafluo- ride System at 173,02 K 84 17. Theoretical and Experimental Enhancement Factors in the Helium-Chlorotrifluoromethane System at 145.21 K 18. Theoretical and Experimental Enhancement Factors in the Helium-Chlorotrifluoromethane System at 180.02 K 86 19. Theoretical and Experimental Enhancement Factors in the Helium-Chlorotrifluoromethane System at 211.06 K 87 20. Theoretical and Experimental Enhancement Factors in the Helium-Chlorotrifluoromethane System at 231.08 K 88 21. Experimentally Determined Henry's Law Constants for the Helium-Carbon Tetrafluo- ride System 105 22. Experimentally Determined Henry's Law Constants for the Helium-Chlorotrifluoro­ methane System 107 23. Comparison of Theoretical and Experimental H"' for the Helium-Carbon Te tr af luor ide 2 119 System . 24. £omparison of Theoretical and Experimental V*^ for the Helium-Carbon Tetrafluoride System 120 xii LIST OF FIGURES (Concluded) Figure Page 25. Comparison of Theoretical and Experimental H^ for the Helium-Chlorotrifluoromethane System 121 26. Comparison of Theoretical and Experimental Vj for the Helium-Chlorotrifluoromethane