T-2854 STEAM PYROLYSIS OF A HYTORTED EASTERN SHALE OIL FOR CHEMICAL INTERMEDIATE PRODUCTION By Steven Paul Sherwood ARTHUR LARES LIBRARY COLORADO SCHOOL ot MINES GOLDEN, COLORADO 80401 ProQuest Number: 10781147 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10781147 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 T-2354 A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Engineering (Chemical and Petroleum-Refining Engineer), Golden, Colorado Date ///&Q/&*/_ -A Signed: Steven Paul Sherwood Approved! ^jr Dr. Victor Yesavage Thesis Advisor Golden, Colorado I ate DjV A.J. Kiqnay L-epatment Head Chemiacal and Petroleum Refining Engineering T-2854 ABSTRACT Eastern shale oil from a Hytort oil shale retort was pyrolyzed with steam at atmospheric pressure in a bench scale tubular reactor packed with ceramic balls. The reaction variables and ranges studied were: temperature from 1395°F to 1632°F, residence time from 0.445 seconds to 1.42 seconds, and a steam to oil mass ratio from 0.449 to 0.931. The maximum yield of olefin product as a weight percent of feed were: Ethylene 12.54 Propylene 5.14 Total Olefin 20.70 The results of these experiments were correlated with a pyrolysis severity factor which combines the effects of three reaction parameters into a single quantity. Increased severity resulted in increased production of hydrogen and carbon monoxide. Ethylene and olefin yield were found to go through a maximum at a temperature of 1478°F, residence time of 0.530 seconds, and steam to oil mass ratio of 0.449. Olefin production was much less then other shale oils investigated at Colorado School of Mines. Therfore this oil would not seem to be an appropriate feed for the petro­ chemical industry. iii T-2854 TABLE OF CONTENTS Fage ABSTRACT................................................ iii LIST OF FIGURES....................................... vi LIST OF T A B L E S ....................................... vii ACKNOWLEDGEMENT ....................................... viii INTRODUCTION....................... 1 EXPERIMENTAL BASIS..................................... 6 Chemistry of Pyrolysis ......................... 6 Previous Investigations......................... 6 Institute of Gas Technology .............. 7 Laramie Energy TechnologyCenter ........... 7 Colorado School of Mines.. ............. 8 DuPont....................................... 12 Stone and W e bster......................... 15 REACTION VARIABLES..................................... 18 Feed Composition................................ 18 Reaction Temperature ............................ 18 Residence T i m e ................................... 19 Steam to Oil Mass Ratio......................... 20 Pyrolysis Severity Factor....................... 21 FEEDSTOCK CHARACTERISTICS ........................... 22 iv T-2854 TABLE OF CONTENT (cont.) Page EXPERIMENTAL APPARATUS. ....................... 24 Feed System..................................... 24. Reactor System ................................ 26 Cooling and Sampling System. ........... 31 SAFETY FEATURES ..................................... 33 EXPERIMENTAL PROCEDURE............................. 34- RESULTS AND DISCUSSION.............................. 37 Effect of Pyrolysis Condition on Yields. 37 Effect of Reaction Temperature.......... 37 Effect of Residence Time................ 38 Effect of Steam to Oil Mass Ratio . 44 Effect of Severity Factor ............... 46 Optimum Ethylene and Olefin Yields ......... 50 Overall Mass Balance......................... 52 Elemental Mass Balance ....................... 52 Reproducibility of Results .................. 54 Comparison with Previous Studies ........... 57 CONCLUSION............................................ 59 RECOMMENDATIONS........................... 61 REFERENCES CITED..................................... 62 APPENDICIES.......................................... 67 A. Computer Program Listing and Notation . 67 A1. Sample Calculations and Equations . 76 B. Computer Program EOSMP.FOR Data Output. 80 C. Simulation Program Data Output.......... 101 v T-2854- LIST OF FIGURES Figure Page 1. Experimemtal Apparatus for Pyrolysis System. 25 2. Reactor Dimensions ................................. 27 3. Reactor S y s t e m....................................... 29 4.. Thermocouple Location................................ 30 5. Effect of Temperature (Wt.? of Feed Vs. Temp.) . 4-0 6. Effect of Temperature (SCF of Feed Vs. Temp.). 4-1 7. Effect of Residence T i m e ........................ 4-3 8. Effect of Griswolds's Severity Factor...........4-7 9. Effect-of Fritzler’s Severity Fa c t o r .............. 4-8 vi T-2854- LIST OF TABLES Table Page 1. Maximum Light Olefin Yields of Tosco II Crude Shale O i l ....................... :9 2. Maximum Light Olefin Yields of Whole Shale Oil. 9 3. Maximum Light Olefin Yields of Distillates. '9 4.. Maximum Light Olefin Yields of Hydrogenated Vacuum Distillates...................................... 13 5. Maximum Light Olefin Yields of Hydrogenated Shale Oils.......................................................13 6. Steam Pyrolysis of Paraho Shale O i l ..................14- 7. Steam Pyrolysis Yeilds (Ruderhausen and Thompson) 16 8. Steam Pyrolysis of Parahoe Shale Oil and Petroleum Gas oil (Korsi, Halle, and Virk)......................17 9. Physical Properties of Eastern Shale Oil. .... 23 10. Medium Residence Time Results .................... 39 11. Effect of Residence Time on Product Yield .... 4-2 12. Effect of Steam to Oil Mass Ratio on Product Yield 4-5 13. Results of Steam Pyrolysis of Eastern Shale Oil . 4-9 14-. Maximum Olefin Y i e l d s ............. 51 15. Overall Mass Balance................................... 53 16. Elemental Mass Balance.................................55 17. Reproducibility of Pyrolysis Run..................... 56 18. Comparison with Computer Model............... 58 ACKNOWLEDGMENT I would like to thand Dr. lesavage and Dr. Dickson for their help with this thesis. I would also like to thank Mike Robinson and Doug Nishamoto for helping with the pyrolysis system. viii T-2854 1 INTRODUCTION Recent fluctuation in crude oil supply and cost have stimulated an interest to utilize the vast reserves of oil shale found in the United States as an alternative fuel source. These cyclic economics are a deterrent to some shale oil projects (1), but Union Oil appears to be determined to produce shale oil from Colorado. In order to produce a synthetic fuel from shale oil, process schemes have been developed which involve coking, hydrostabiliza­ tion, hydrodenitrogenation, reforming and cracking (2,3). Foreign and domestic shale oils were analyzed by The Bureau of Mines in Laramie (4). The results indicate that shale oils differ greatly in such properties as sulfur and hydrocarbon composition. The sulfur containing species are evenly distributed throughout the boiling ranges of the oils, while the nitrogen compound concentration in the higher boiling fractions is much higher then the lower boiling fractions (4). Shale oil naphtha is found to contain about 10 percent nitrogen compounds, light distllates (200-310?C) contain about 20 percent, heavy distilaltes (310-430°C) contain about 40 percent and residuum (430°C+) will contain about 85 percent nitrogen species (5,6). Nitrogen compounds found include pyrroles, pyridines, and quinoline homologs, all of which have the T-2854 2 chemical properties of a weak base (7). Typically shale oil will have a nitrogen content of about 2 weight percent (8,9). Cady et al. (7) report that NTU shale oil consists of 39 percent hydrocarbon compounds and 61 percent nonhydrocarbon species. Of the nonhydrocarbons, 59 percent are nitrogen containing compounds, 10 percent are sulfur containing compounds and 31 percent are oxygen containing compounds. The basic nitrogen compounds found in shale oil act as poisons to modern acidic type catalysts (2). Since most of the processes in a refinery are catalytic, it is necessary to remove the nitrogen before processing (10). This could be done by hydrodenitrogenation (2), of hydrofining (9). Cheveron research reports that it would cost between $6.50 and $9.70 (1978 prices) a barrel to refine shale oil. Most of this cost is associated with the initial step of reducing the nitrogern content of the oil (11). Any alternative use for shale oil that does not involve prerefining may be both practical and economical. An alternative use for shale oil may be as a feedstock for the production of petrochemical intermediates such as ethylene, propylene, butadiene, benzene, toluene and xylene. Steam pyrolysis of hydrocarbons is the most extensively used method of production of these intermediates (12,13). Since pyrolysis is a noncatalytic process, it does not require expensive prerefining to reduce the nitrogen content of a T-2854 3 shale oil. Pyrolysis to form pertrochemical intermediates may therefore be an attractive