Abstract Process Economics Program Report 246 NEAR ZERO SULFUR DIESEL FUEL (November 2002) Desulfurization of diesel fuel is growing worldwide into a process critical to petroleum refinery profitability. Worldwide environmental awareness led countries in the major developed regions to legislate almost sulfur-free highway diesel fuel for their markets by 2005-2007. Near zero sulfur (NZS) diesel fuel of 15 ppm sulfur or less allows advanced post engine exhaust clean up devices that remove emissions and particulate material to function. Currently the most common sulfur specification is 500 ppm (350 ppm in Europe) with higher limits in some countries. Ultra low sulfur diesel (ULSD) fuel of less than 50 ppm becomes the specification in both the European Union and Japan in 2005. The European Commission further adopted a 10 ppm sulfur specification for road diesel fuel beginning January 1, 2005 with full conversion by 2010. An U.S. EPA rule phases in 15 ppm sulfur highway diesel fuel starting June 1, 2006. U.S. pipelines are anticipated to require a sulfur level somewhat below 10 ppm to be able to deliver less than 15 ppm fuel. In Japan, 10 ppm sulfur fuel in 2007 is proposed. Countries in other regions of the world are also working to reduce the sulfur in diesel fuel. In order to meet these specifications, the capital investment needed by the refining industry is anticipated to be substantial (estimates range from $3 to 13 billion for the U.S. industry). This report reviews the chemistry, technology and economics of producing diesel fuel meeting the new NZS specifications slated for 2005 and beyond. A number of improved hydrodesulfurization processes and catalysts are commercial. Adsorption and oxidation processes requiring little or no additional hydrogen are offered for license. Other processes are under development. Revamping of existing hydrotreaters is reviewed. We evaluate the economics of a generic hydrotreating process to produce a low aromatic NZS diesel fuel. This report should provide a useful overview of near zero sulfur diesel fuel and its properties with in-depth review of process developments and economics within the industry. People involved in the energy industry, professionals who research, develop, plan, operate, design plants or manage investments in the petroleum refining industry as well as those in allied industries could benefit from the information contained in this report. PEP 02 RHN
CONTENTS 1 INTRODUCTION... 1-1 2 CONCLUSIONS... 2-1 3 SUMMARY... 3-1 COMMERCIAL ASPECTS... 3-1 TECHNICAL ASPECTS... 3-2 ECONOMIC ASPECTS... 3-3 4 INDUSTRY STATUS... 4-1 U.S. MARKET CONCERNS... 4-3 Distribution and Contamination Issues... 4-4 "Small" Diesel Refiners... 4-5 U.S. DIESEL DEMAND... 4-5 INSTALLED CAPACITY... 4-7 NEW CONSTRUCTION... 4-14 PROCESS TECHNOLOGIES AVAILABLE... 4-15 UOP... 4-15 Criterion and Shell... 4-16 Axens... 4-16 Akzo Nobel Catalysts... 4-17 Phillips Petroleum... 4-17 CrystaTech... 4-17 Other Process Developments... 4-18 COST OF PRODUCING NZSD... 4-18 CATALYSTS PRICES... 4-20 5 GENERAL PROCESS REVIEW... 5-1 DIESEL ENGINES... 5-2 iii
CONTENTS (Continued) TYPES OF DIESEL FUELS... 5-3 Grade... 5-3 Alternate Diesel Fuels... 5-6 Fischer-Tropsch Diesel Fuels... 5-7 Biodiesel Fuels... 5-9 Ethanol-Diesel Blends... 5-13 Dimethyl Ether... 5-14 Compressed Natural Gas... 5-14 DIESEL FUEL CHEMISTRY... 5-14 Diesel Fuel Composition... 5-15 Sulfur... 5-20 Nitrogen and Oxygen... 5-21 Diesel Fuel Characterization... 5-21 Cetane Number (Index)... 5-22 Boiling Range, Distillation, Volatility, and Flash Point... 5-25 Density and Viscosity... 5-25 Heating Value... 5-26 Cloud Point, Pour Point, and Low-temperature Filterability... 5-26 Foam... 5-27 Color... 5-27 Sulfur... 5-27 Aromatics... 5-27 Stability... 5-28 Diesel Fuel Incompatibility... 5-28 ADDITIVES... 5-31 Anti-static Additives... 5-33 Lubrication... 5-33 Stabilizers... 5-33 Emissions... 5-33 iv
CONTENTS (Continued) HYDROTREATING REACTION PATHWAYS... 5-34 Hydrodesulfurization... 5-36 Hydrodenitrogenation... 5-39 Hydrodeoxygenation... 5-42 Olefin and Aromatics Hydrogenation... 5-44 Interaction of Heteroatoms... 5--45 KINETICS... 5-46 Hydrodesulfurization... 5-47 Thiophene... 5-49 Benzothiophene... 5-50 Dibenzothiophene... 5-51 Interaction of Heteroatoms... 5-52 Hydrodenitrogenation... 5-53 Ortho-Propylaniline... 5-53 Pyridine and Piperidine... 5-54 Interaction of Heteroatoms... 5-54 Hydrogenation of Aromatics... 5-55 Middle Distillate Feedstock... 5-56 HYDROTREATING CATALYSTS FOR NZS DIESEL... 5-62 Catalyst Metals... 5-64 Catalyst Structure and Presulfiding... 5-65 Catalyst Supports... 5-67 Additives... 5-69 Commercial Catalysts... 5-70 Akzo Nobel... 5-72 Advanced Refining Technologies... 5-73 Axens... 5-74 Criterion... 5-74 v
CONTENTS (Continued) Sud-Chemie... 5-75 Developmental Catalysts... 5-75 CoMo on Al MCM-41... 5-76 Nickel Phosphide... 5-77 Catalyst Deactivation, Regeneration and Disposal... 5-78 6 HYDROPROCESSING... 6-1 REFINING SCHEME... 6-2 HYDROCRACKING... 6-4 FCC FEED HYDROTREATMENT... 6-6 HDS PRETREATMENT PROCESS... 6-7 Diesel Isotherming Process... 6-7 National Center for Scientific Research Process... 6-8 LCO UPGRADING... 6-9 HYDROTREATING PROCESS REVIEW... 6-11 Commercial Diesel HDS Processes... 6-11 Haldor Topsoe Two-Stage HDS / HDA Process... 6-12 MAKfining Premium Distillate Technologies... 6-14 MQD Unionfining Process (UOP)... 6-18 Feedstock Effects... 6-21 Reactor Design... 6-21 Temperature... 6-22 LHSV... 6-23 H 2 Partial Pressure... 6-23 Recycle Gas H 2 S Concentration... 6-25 Recycle Gas: Oil Ratio... 6-25 Reactor Internals... 6-26 Control and Optimization... 6-28 vi
CONTENTS (Continued) DIESEL HDT REVAMPING... 6-31 Refinery Operational Options... 6-32 HDS Revamping Options... 6-34 Revamping Case Studies... 6-36 Moderate Pressure Unit Revamp... 6-36 Low Pressure Unit Revamp... 6-38 Commercial Experience... 6-38 PROCESS DESCRIPTION... 6-41 Reaction -- Section 100... 6-51 Gas Recovery -- Section 200... 6-51 Purification -- Section 300... 6-51 PROCESS DISCUSSION... 6-52 Feedstock... 6-52 Product Yields and Quality... 6-52 Reaction -- Section 100... 6-53 Gas Recovery - Section 200... 6-54 Purification - Section 300... 6-54 Hydrogen Systems... 6-54 Materials of Construction... 6-55 Waste Treatment and Disposal... 6-55 Comparison with Previous PEP Hydrotreaters... 6-55 COST ESTIMATES... 6-56 Capital Costs... 6-56 Production Costs... 6-59 7 SORPTION PROCESSES... 7-1 S ZORB TM - DIESEL SULFUR REMOVAL TECHNOLOGY... 7-1 Process Description... 7-2 vii
CONTENTS (Concluded) Pilot Plant Results... 7-2 Sorbent... 7-5 Economics... 7-6 Application to H 2 S Removal... 7-6 HALDOR TOPSOE PROCESS... 7-7 EXXONMOBIL PROCESS... 7-7 SELECTIVE ADSORPTION FOR REMOVING SULFUR... 7-7 RESEARCH TRIANGLE INSTITUTE PROCESS... 7-8 8 OTHER PROCESSES... 8-1 DESULFURIZATION PROCESSES... 8-1 ASR-2 Diesel Desulfurization Process... 8-1 Process Description... 8-2 Product Quality... 8-4 Cost Estimate... 8-4 Conversion / Extraction Desulfurization Process... 8-4 BP Oxidative Polishing... 8-5 SulphCo Process... 8-6 Diesel Clean Extraction... 8-6 Biodesulfurization... 8-6 CRYSTASULF SM PROCESS... 8-7 APPENDIX A: PATENT SUMMARY TABLES... A-1 APPENDIX B: DESIGN AND COST BASES... B-1 APPENDIX C: CITED REFERENCES... C-1 APPENDIX D: PATENT REFERENCES BY COMPANY... D-1 APPENDIX E: PROCESS FLOW DIAGRAM... E-1 viii
ILLUSTRATIONS 4.1 Diesel / Heating Oil Price Differentials... 4-19 5.1 Transesterification Reaction... 5-10 5.2 Selected Functional Groups Found in Diesel Fuel... 5-19 5.3 Typical Hydrotreating Reactions... 5-35 5.4 Simplified HDS Pathways... 5-37 5.5 Hydrodenitrogenation Pathways... 5-41 5.6 Comparison of HDO and HDS Pathways... 5-43 5.7 Hydrogenation of Tetralin... 5-44 6.1 Washington Redar Process... 6-9 6.2 Haldor Topsoe Two-Stage HDS / HDA Process... 6-12 6.3 MAKfining Two-Stage HDS / HDA Process... 6-15 6.4 MQD Unionfining Process... 6-19 6.5 Effect of WABT on Product Sulfur Content... 6-22 6.6 Effect of H 2 Partial Pressure on WABT... 6-23 6.7 Shell's Green GasOil Control Scheme... 6-30 6.8 Near Zero sulfur Diesel Hydrotreater... E-3 7.1 Phillips Szorb TM - Diesel Process... E-5 7.2 S Zorb Product Sulfur... 7-3 7.3 S Zorb Hydrogen Consumption... 7-3 7.4 S Zorb SRT vs. Hydrotreating... 7-4 8.1 Simplied Unipure ASR-2 Process (246277)... 8-3 8.2 Petro Star's Conversion / Extraction Desulfurization Process (246345)... 8-5 ix
TABLES 3.1 Summary of Cost Estimates for A NZS Diesel Fuel Hydrotreater... 3-5 4.1 European and U.S. Diesel Fuel Specifications... 4-2 4.2 U.S. Distillate Demand... 4-6 4.3 U.S. Distillate Supply... 4-7 4.4 Diesel Hydrotreating Refineries - North America... 4-8 4.5 Diesel Hydrotreating Refineries - Western Europe... 4-10 4.6 Diesel Hydrotreating Refineries - Asia-Pacific... 4-11 4.7 Diesel Hydrotreating Refineries - Central & Eastern Europe, South & Central America, Middle East, Africa... 4-12 4.8 Diesel Hydrotreating Refineries - World Summary... 4-13 4.9 Diesel Hydrotreating Refineries - Distribution of Capacities... 4-14 4.10 Comparison of ULSD Production Cost Estimates... 4-19 5.1 Typical Speed Ranges of Three Types of Diesel Engines... 5-3 5.2 General ASTM D-975 Specifications for Three Diesel Fuel Grades... 5-4 5.3 Properties of Diesel Fuels... 5-6 5.4 GTL Diesel Fuel Compared to Sweden's Class I Diesel Fuel... 5-7 5.5 Comparison of Sasol SPD F-T Diesel Properties with Conventional and Carb Diesel Fuels... 5-8 5.6 Properties of Petroleum Diesel Fuel, Soybean Oil, Rapeseed Oil, and Ester Fuels... 5-11 5.7 Typical Properties and Composition of Diesel Fuel Blendstocks... 5-16 5.8 Aromatics Distribution in Diesel Blendstocks... 5-17 5.9 Functional Groups Listed in Order of Incompatibility Reactions in Diesel Fuels... 5-18 5.10 Boiling Points of Sulfur Compounds in Diesel Fuel and Steric Hindrance Classification... 5-20 5.11 Cetane Number and Auto-Ignition Temperature of Selected Hydrocarbons... 5-23 5.12 Typical Cetane Numbers of Refinery Blendstocks... 5-24 x
TABLES (Continued) 5.13 Classification of Organic Nitrogen Compounds for Sediment Formation in Middle Distillates... 5-30 5.14 Representative Diesel Fuel Additives... 5-32 5.15 Rate Constants of Thiophenic Compounds... 5-48 5.16 Isthmus/Maya Straight Run Gas Oil Feedstock Characterization... 5-58 5.17 Kinetic Constants for HDS of Three Sulfur Components of Middle Distillate... 5-61 5.18 Relative Activity for HDS of DBT of Transition Metal Sulfides... 5-64 5.19 Selection of HDS Catalyst Type for Producing NZS Diesel Fuel... 5-71 5.20 Characterization of Six Commercial Catalysts (CA 1996)... 5-71 5.21 Akzo Nobel's Nebula Catalyst Compared to Stars KF-848 Catalyst... 5-72 5.22 Comparison of Nicomo Catalyst with NIMO Catalyst for NZS Diesel... 5-74 5.23 CoMo on Al MCM-41 Catalyst Compared to CoMo on Alumina Catalysts- HDS of DBT a... 5-76 5.24 HDS of Ni 2 P Catalyst Compared to Conventional CoMo Catalyst a... 5-77 6.1 Effect of Feedstock on Diesel Quality in Single Stage Hydrocracking... 6-5 6.2 Hydrocracking Catalyst Effects Quality of Diesel from Highly Aromatic Cracked Feedstock... 6-6 6.3 Washington Redar Process LCO Upgrading Pilot Plant Results... 6-11 6.4 Haldor Topsoe Two-Stage Diesel HDS / HDA Unit Performance... 6-13 6.5 HDS Catalyst-Hydrocracking Catalyst Beds in a Single-Stage Pilot Plant Reactor... 6-16 6.6 MAKfining Isomerization Dewaxing Pilot Plant Performance... 6-17 6.7 Revamping of a European HDS Unit with MAKfining Process... 6-18 6.8 MQD Unionfining Process Study Using Dewaxing and HDA... 6-20 6.9 MQD Unionfining Process Study for European Refinery... 6-20 6.10 Effect of H 2 Partial Pressure... 6-24 6.11 Effect of Recycle Gas H 2 S Concentration on WABT... 6-25 6.12 Effect of Recyle Gas: Oil Ratio... 6-26 6.13 Number of Suppliers of 14 ft. I.D. HDT Reactors by Wall Thickness... 6-32 xi
TABLES (Continued) 6.14 Comparison of Technologies Useful in Meeting 15 PPMW Sulfur Maximum... 6-35 6.15 Summary of Revamped Reactor Conditions... 6-37 6.16 Scanraff, Sweden, HDS Unit Operation for Class I City Diesel Fuel... 6-39 6.17 Beta Refining HDA Operation in Production of Swedish Class I City Diesel Fuel... 6-40 6.18 Shell Gothenburg, Sweden, Production of Class I City Diesel Fuel... 6-40 6.19 Design Bases and Assumptions... 6-42 6.20 Feedstock Characterization... 6-43 6.21 Liquid Products Characterization... 6-43 6.22 NZS Diesel Hydrotreater Stream Flows... 6-44 6.23 NZS Diesel Hydrotreater Major Equipment... 6-48 6.24 NZS Diesel Hydrotreater Utilities Summary... 6-50 6.25 NZS Diesel Hydrotreater Total Capital Investment... 6-58 6.26 NZS Diesel Hydrotreater Capital Investment by Section... 6-62 6.27 NZS Diesel Hydrotreater Production Costs... 6-63 6.28 Estimated Differential in Product Value Between NZS and 500 PPM Sulfur Diesel Fuels... 6-65 7.1 Diesel Feedstock Composition... 7-2 7.2 Desulfurization of Different Diesel Feedstocks (Pilot Plant Results)... 7-5 A.1 General NZS Diesel Fuel Patent Summary... A-3 A.2 Diesel Fuel Compositions Patent Summary... A-10 A.3 Additives for Diesel Fuels Patent Summary... A-12 xii
TABLES (Concluded) A.4 Diesel Fuel Hydrotreating Patent Summary... A-19 A.5 Diesel Fuel Stock by Hydrocracking Patent Summary... A-28 A.6 NZS Diesel Fuel by Sorption Processes Patent Summary... a-33 xiii