Production and processing of sour crude and natural gas - challenges due to increasing stringent regulations Darkhan Duissenov Petroleum Engineering Submission date: June 2013 Supervisor: Jon Steinar Gudmundsson, IPT Norwegian University of Science and Technology Department of Petroleum Engineering and Applied Geophysics Production and processing of sour crude and natural gas – challenges due to increasing stringent regulations Darkhan Duissenov Petroleum engineering Submission date: June 2013 Supervisor: Jon Steinar Gudmundsson Norwegian University of Science and Technology Faculty of Engineering Science and Technology Department of Petroleum Engineering and Applied Geophysics Trondheim, Norway Abstract The worldwide demand for petroleum is growing tremendously. It is expected that the demand will have incremental capacity of 20 mb/d for crude oil, reaching 107.3 mb/d, and demand for natural gas will rise nearly 50% to 190 tcf in 2035, compared to 130 tcf now. According to the International Energy Agency 70% of crude oil reserves and 40% of natural gas reserves are defined as having high content of organosulfur compounds. Obviously, for decades to come, to satisfy the growing global needs for fossil fuels, reservoirs with sour contaminants will be developed intensively. The sulfur compounds in crude oils and natural gas generally exist in the form of free sulfur, hydrogen sulfide, thiols, sulfides, disulfides, and thiophenes. These compounds can cause considerable technical, environmental, economic, and safety challenges in all segments of petroleum industry, from upstream, through midstream to downstream. Currently, the sulfur level in on-road and off-road gasoline and diesel is limited to 10 and 15 ppm respectively by weight in developed countries of EU and USA, but this trend is now increasingly being adopted in the developing world too. Furthermore, it has to be expected that the sulfur level requirements will become more and more strict in the foreseeable future, approaching zero sulfur emissions from burned fuels. The production of ultra low sulfur automotive fuels has gained enormous interest in the scientific community worldwide. Oxidative desulphurization, biocatalytic desulphurization, and combined technologies, which are alternatives to conventional hydrodesulphurization technology, are much more efficient and more economical in removing complex sulfur compounds, especially benzothiophene, dibenzothiophene and their alkyl derivatives. Keywords: product quality specifications, H2S corrosion, hydrodesulphurization, biocatalytic desulphurization, oxidative desulphurization i Acknowledgment This project would not have been possible without the help and contributions of others. I hereby seize the opportunity given to acknowledge these people for their assistance whenever I found myself in doubt of what to do and how to do it. First and foremost I offer my sincerest gratitude to my supervisor Professor Jon Steinar Gudmundsson for his excellent guidance, support and encouragement during this project. I really appreciate for his ideas, answers to all my questions and positive attitude. I would like also to acknowledge the Government of the Republic of Kazakhstan represented by the “Centre for International Programs” which provided funding to complete Master of Science in Petroleum Engineering degree at NTNU. The International Scholarship of the President of Kazakhstan “Bolashak” helped me to make my dreams come true. It is a great pleasure to thank my friends Gulia Shafikova, Danila Shutemov, Roman Shpak and honorable Kazakh friends for support, unforgettable time and life lessons. I am truly indebted and thankful to my lovely family for support and belief during my studies abroad. ii Table of Contents ABSTRACT ........................................................................................................................ I ACKNOWLEDGMENT .................................................................................................. II LIST OF FIGURES .......................................................................................................... V LIST OF TABLES ....................................................................................................... VIII 1. INTRODUCTION...................................................................................................... 1 2. WORLD PETROLEUM RESERVES ..................................................................... 3 3. PETROLEUM SUPPLY AND DEMAND OUTLOOK ......................................... 5 4. CRUDE QUALITY OUTLOOK .............................................................................. 8 4.1 DENSITY AND API GRAVITY OF CRUDE OIL ............................................................... 8 4.2 SWEET AND SOUR CRUDE OIL .................................................................................... 9 4.3 BENCHMARKS OF CRUDE OIL................................................................................... 10 4.4 FUTURE TRENDS ON CRUDE QUALITY CHARACTERISTICS ........................................ 12 4.5 PRODUCT QUALITY SPECIFICATIONS ....................................................................... 12 5. CHALLENGES IN PRODUCTION AND PROCESSING ................................. 19 5.1 CORROSION ............................................................................................................. 20 5.1.1 Corrosion in petroleum production operations ............................................. 21 5.1.2 Corrosion in petroleum refining and petrochemical operations ................... 22 5.2 CORROSION CONTROL MECHANISMS IN SOUR SYSTEMS ........................................... 23 5.3 CORROSION MITIGATION TECHNIQUES IN SOUR SYSTEMS ........................................ 25 6. PETROLEUM PRODUCTS ................................................................................... 28 6.1 CLASSIFICATION OF PETROLEUM PRODUCTS ........................................................... 28 7. COMPOSITION OF CRUDE OILS AND PETROLEUM PRODUCTS .......... 29 7.1 HYDROCARBON COMPOUNDS .................................................................................. 29 7.2 NON–HYDROCARBON COMPOUNDS ........................................................................ 32 8. SULFUR CONTENT OF CRUDE OILS .............................................................. 34 8.1 ORIGIN OF SULFUR .................................................................................................. 34 8.2 NATURE OF SULFUR COMPOUNDS ............................................................................ 35 iii 9. FUNDAMENTALS OF REFINERY PROCESSING .......................................... 40 9.1 CLASSIFYING REFINERIES BY CONFIGURATION AND COMPLEXITY ........................... 41 10. CLASSIFICATION OF DESULPHURIZATION TECHNOLOGIES .............. 42 11. HYDROTREATING ............................................................................................... 43 11.1 HYDRODESULPHURIZATION ................................................................................ 44 11.2 PROCESS PARAMETERS ........................................................................................ 45 12. UNCONVENTIONAL DESULPHURIZATION TECHNOLOGIES ................ 49 12.1 OXIDATIVE DESULPHURIZATION ......................................................................... 49 12.2 BIOCATALYTIC DESULPHURIZATION ................................................................... 51 12.2.1 Process aspects .......................................................................................... 52 12.2.2 Barriers for commercialization ................................................................. 53 12.3 NOVEL COMBINED TECHNOLOGIES ...................................................................... 56 13. NATURAL GAS....................................................................................................... 60 13.1 ASSOCIATED AND NON-ASSOCIATED GAS ............................................................ 60 13.2 SWEET AND SOUR NATURAL GAS ......................................................................... 60 13.3 GAS SWEETENING PROCESSES ............................................................................. 61 13.4 PROCESS SELECTION FACTORS ............................................................................ 66 14. REFINERY OF THE FUTURE ............................................................................. 66 14.1 GLOBAL REFINERY CAPACITY REQUIREMENTS IN THE FUTURE ............................ 70 15. EFFECT OF ORGANOSULFUR COMPOUNDS ON NATURAL GAS PROPERTIES .................................................................................................................. 73 15.1 PURE COMPONENTS BEHAVIOR............................................................................ 74 15.2 ESTIMATION OF WATER CONTENT IN SOUR GASES ............................................... 75 SUMMARY ...................................................................................................................... 79 CONCLUSION ................................................................................................................ 81 BIBLIOGRAPHY ............................................................................................................ 82 APPENDICES .................................................................................................................. 89 iv List of figures FIGURE 1 DISTRIBUTION OF PROVED RESERVES OF CRUDE OIL IN 1991, 2001 & 2011 .........