PETROCHEMICALS from REFINERY STREAMS (February 2000)

Abstract Process Economics Report 169B PETROCHEMICALS FROM REFINERY STREAMS (February 2000)

Lyondell’s (formerly Arco’s) SuperflexSM process and Mobil’s Olefin Interconversion (MOI) process are two new secondary olefin conversion technologies that crack C4-C8 olefins to pre- dominately ethylene and propylene. Both technologies are based on a reactor/regenerator design similar to conventional fluid catalytic cracking (FCC). Alternatively, Asahi’s Alpha process converts C4-C8 olefins to aromatics, mainly benzene, toluene, and xylenes (BTX). In the Alpha process, hydrogen circulation maintains stable catalyst activity for 3 days; therefore, this process can oper- ate in a two-fixed bed swing reactor system. Shape-selective medium-pore zeolite catalysts are at the heart of the three processes. Reac- tion thermodynamics determine the product slate and selectivity independent of feedstock sources. Suitable feedstocks include light cracked naphtha (LCN), coker naphtha, steam cracker C4/C5, and light pyrolysis gasoline. Olefin cracking technology offers the opportunity to decouple propylene supply from ethylene production. The quantity of polymer-grade propylene produced by either the Superflex or MOI process based on LCN from a 65,000 b/d FCC unit exceeds that recovered from a 1 billion lb/yr (world-scale) naphtha-based ethylene plant. A similar amount of LCN could produce BTX equiva- lent to that of a 44,5000 b/d catalytic reformer. Economic analyses show that it is more attractive to convert LCN to light olefins than to aromatics, although more than twice the capital investment is required. During periods of high demand (e.g., the mid-1990s), the simple return on investment for the MOI and Superflex process could have reached 20% and 30%, respectively. Because of the volatility in commodity prices, these two processes could not cover cash costs during other times in the 1990s. Lower capital investment cost fail to make the Alpha process economically viable because paraffinic by-products constitute 40% of the process yield. By nature, aromatization reactions generate hydrogen, which in turn saturates olefinic components and downgrades them to fuel.

PEP’98 169B EJC CONTENTS

GLOSSARY...... xiii 1 INTRODUCTION ...... 1-1 REFINERY PROFITABILITY ...... 1-1 GASOLINE REGULATIONS...... 1-4 SECONDARY OLEFIN CONVERSION TECHNOLOGY...... 1-4 2 SUMMARY...... 2-1 TECHNICAL ASPECTS...... 2-1 Conversion to Light Olefins...... 2-1 Chemistry...... 2-1 Process Design ...... 2-2 Conversion to Aromatics...... 2-3 Chemistry...... 2-3 Process Design ...... 2-3 ECONOMIC ASPECTS ...... 2-4 Olefins Production from LCN...... 2-6 Aromatics Production from LCN ...... 2-9 3 OLEFINS AND AROMATICS SOURCES...... 3-1 LIGHT OLEFIN PRODUCTION...... 3-5 Light Olefins from Steam Cracking...... 3-5 Light Olefins from Refinery Sources...... 3-6 Fluid Catalytic Cracking...... 3-7 Deep Catalytic Cracking ...... 3-8 On-Purpose Olefin Production...... 3-8 Propylene from Ethylene Metathesis (Disproportionation) ...... 3-8 AROMATICS PRODUCTION ...... 3-9 Sources of BTX Aromatics ...... 3-9 Conventional Catalytic Reforming ...... 3-10 Zeolite Reforming ...... 3-11 Pyrolysis Gasoline ...... 3-12 Nonconventional Aromatics Sources...... 3-14

i CONTENTS (Continued)

4 CHEMISTRY REVIEW (Concluded) Monomolecular Reactions ...... 4-13 Pentene Cracking ...... 4-15 Hexene Cracking ...... 4-16 Heptene Cracking...... 4-17 Octene Cracking...... 4-19 Aromatization Mechanism ...... 4-21 5 FLUID CATALYTIC CRACKING PROCESS REVIEW...... 5-1 FLUIDIZATION ...... 5-1 REACTOR/REGENERATION ...... 5-1 Reactor Riser...... 5-5 Feed Injection ...... 5-5 Riser ...... 5-5 Vapor/Catalyst Separation ...... 5-6 Spent Catalyst Stripper ...... 5-6 Catalyst Transfer to Regenerator ...... 5-7 Regeneration ...... 5-7 Heat Balance ...... 5-8 VAPOR RECOVERY SECTION ...... 5-9 6 SUPERFLEXSM PROCESS ...... 6-1 PROCESS REVIEW...... 6-1 Process Conditions...... 6-1 Catalyst ...... 6-2 Superflex Chemistry ...... 6-5 Feedstocks ...... 6-5 Product Distribution...... 6-5 PROCESS DESCRIPTION...... 6-8 Section 100—Cracking and Fractionation ...... 6-8 Section 200—Ethylene Recovery ...... 6-9 Section 300—Propylene Recovery ...... 6-9 PROCESS DISCUSSION...... 6-16 Design Capacity...... 6-16

iii CONTENTS (Continued)

6 SUPERFLEXSM PROCESS (Concluded) Reactor/Regeneration...... 6-17 Recycle Ratio...... 6-17 Product Recovery ...... 6-17 Ethylene Recovery...... 6-18 Propylene Recovery...... 6-18 COST ESTIMATES ...... 6-19 Investment Costs ...... 6-19 Production Costs ...... 6-20 Feedstock Value Sensitivity ...... 6-26 By-product Value Sensitivity ...... 6-27 7 MOBIL OLEFIN INTERCONVERSION PROCESS...... 7-1 PROCESS REVIEW...... 7-1 Reaction Conditions...... 7-1 Feedstock ...... 7-1 Catalyst ...... 7-2 Cracking Reactions...... 7-2 Product Distribution...... 7-4 PROCESS DESCRIPTION...... 7-5 Section 100—Cracking and Fractionation ...... 7-5 Section 200—Ethylene Recovery ...... 7-6 Section 300—Propylene Recovery ...... 7-6 PROCESS DISCUSSION...... 7-13 Design Capacity...... 7-13 Reactor/Regenerator ...... 7-14 Recycle Ratio...... 7-14 Product Recovery ...... 7-14 Ethylene Recovery...... 7-15 Propylene Recovery...... 7-15 COST ESTIMATES ...... 7-16 Investment Costs ...... 7-16 Production Costs ...... 7-17 Feedstock Value Sensitivity ...... 7-23

iv By-product Value Sensitivity ...... 7-23

CONTENTS (Concluded)

8 ALPHA PROCESS...... 8-1 PROCESS REVIEW...... 8-1 Gasoline Mode...... 8-1 Petrochemical Mode ...... 8-2 Process Conditions...... 8-3 Catalyst ...... 8-3 Feedstocks ...... 8-4 Product Selectivity ...... 8-4 PROCESS DESIGN...... 8-5 Section 100—Reaction ...... 8-5 Section 200—Extractive Distillation ...... 8-5 Section 300—Benzene/Toluene Recovery ...... 8-6 Section 400—Xylene Recovery ...... 8-6 PROCESS DISCUSSION...... 8-15 Reaction Conditions...... 8-15 Aromatics Separation from Nonaromatics...... 8-16 COST ESTIMATES ...... 8-16 Capital Investment ...... 8-16 Production Costs ...... 8-17 Raw Material and Product Prices ...... 8-23 Variable Costs ...... 8-23 Profitability ...... 8-24 APPENDIXES A PATENT SUMMARY TABLE B DESIGN AND COST BASES C CITED REFERENCES D PATENT REFERENCES BY COMPANY E POTENTIAL UPGRADABLE CRACKING REFINERY CAPACITIES WORLDWIDE F PROCESS FLOW DIAGRAMS

v FIGURES

1.1 Annual U.S. Gulf Coast Cracking Refining Margins, 1991-1999 ...... 1-2 1.2 Annual Rotterdam Reforming/Cracking Refining Margins, 1991-1999...... 1-2 1.3 Annual Singapore Topping/Reorming Refining Margins, 1991-1999 ...... 1-3 2.1 Equilibrium Olefin Distribution...... 2-2 2.2 Superflex vs. MOI Production Economics, 1999 ...... 2-6 2.3 Olefin Production Economics, 1990-1999 (Feedstock: FCC LCN)...... 2-7 2.4 Olefin Production Economics, 1990-1999 (Dilute Ethylene Value as Fuel)...... 2-8 2.5 Alpha Process Production Economics, 1990-1999...... 2-9 3.1 Monthly U.S. Gulf Coast Cracking Refining Margins, 1991-1999...... 3-2 3.2 Monthly Rotterdam Reforming/Cracking Refining Margins, 1991-1999 ...... 3-2 3.3 Monthly Singapore Topping/Reforming Refining Margins, 1991-1999 ...... 3-3 4.1 Equilibrium Olefin Distribution...... 4-8 4.2 ß-Scission of the Pentene Carbenium Ion...... 4-15 4.3 Pentene Cracking Reaction: Hydrogen Transfer and Cyclization...... 4-15 4.4 ß-Scission of the Hexene Carbenium Ion...... 4-16 4.5 ß-Scission of the Heptene Carbenium Ion...... 4-18 4.6 ß-Scission of the Octene Carbenium Ion...... 4-20 4.7 Paraffin and Olefin Aromatization ...... 4-21 4.8 Olefin and Aromatic Yields ...... 4-23 5.1 ... UOP’S FCC Reactor...... 5-2 5.2 .. Kellogg’s FCC Reactor ...... 5-3 5.3 .. Exxon’s FCC Flexicracking® Unit...... 5-4 6.1 Phosphorus Bonding Mechanism ...... 6-3 6.2 Superflex Process Chemistry ...... 6-5 6.3 Superflex Process...... F-3 6.4 Superflex Investment Requirement, 1999 ...... 6-20 6.5 Superflex Production Economics, 1990-1999...... 6-25 6.6 U.S. Gulf Coast Product and Feedstock Costs, 1990-1999 ...... 6-25 6.7 Effect of Feedstock Value on Superflex Production Economics ...... 6-25 6.9 Superflex Production Economics, 1990-1999...... 6-27 7.1 Simplified MOI Process Flow...... 7-2 7.2 MOI Process Chemistry...... 7-3

vi FIGURES (Concluded)

7.3 MOI Investment Requirement, 1999...... 7-17 7.4 MOI Production Economics, 1990-1999...... 7-22 7.5 U.S. Gulf Coast Feedstock and Product Costs, 1990-1999 ...... 7-22 7.6 Effect of Feedstock Value on MOI Production Economics 1999...... 7-23 7.7 MOI Production Economics, 1990-1999...... 7-24 8.1 BTX Yield vs. Reaction Temperature ...... 8-4 8.2 Alpha Process...... F-7 8.3 Alpha Process Investment Requirement, 1999 ...... 8-17 8.4 Alpha Product Spot Prices, 1990-1999...... 8-23 8.5 Alpha Process Production Economics, 1990-1999...... 8-24

vii TABLES

1.1 Gasoline Specifications ...... 1-4 2.1 Product Yield: Superflex vs. MOI...... 2-2 2.2 Alpha vs. Catalytic Reforming under Aromatics Production ...... 2-4 2.3 Petrochemical Production from FCC LCN...... 2-5 3.1 Annual Refining Margins, 1991-1999...... 3-4 3.2 World Conversion Refinery Capacity—as of January 1999...... E-3 3.3 World Conversion Refinery Capacity— United States and Canada as of January 1999 ...... E-4 3.4 World Conversion Refinery Capacity: Europe—as of January 1999 ...... E-12 3.5 World Conversion Refinery Capacity: Asia-Pacific—as of January 1999...... E-18 3.6 World Conversion Refinery Capacity: Middle East and Africa—as of January 1999...... E-23 3.7 World Conversion Refinery Capacity: Latin America and the Caribbean—as of January 1999 ...... E-26 3.8 Propylene Sources, 1998...... 3-5 3.9 Light Olefin Yields from Steam Cracking...... 3-6 3.10 DCC vs. FCC Yields ...... 3-7 3.11 Commercial DCC Units...... 3-8 3.12 World BTX Production by Source, 1998...... 3-10 3.13 Estimated Yields during Ethylene Manufacture Ratio of BTX Production to Ethylene Production, 1998 ...... 3-13 3.14 World Gasoline Specifications...... 3-14 3.15 U.S. RFG Quality, Summer 1998: Actual Regular Unleaded Average—Phase I ...... 3-15 3.16 U.S. Conventional Gasoline Quality...... 3-16 3.17 CARB Reformulated Gasoline Requirements ...... 3-16 3.18 Reactive Olefins...... 3-19 3.19 Typical FCC Light Olefin Yields ...... 3-20 4.1 C5-C8 Olefin Conversion to Ethylene, Propylene, and Aromatics Patent Summary ...... A-3 4.2 LCN Atmospheric Reactivity and Volatility...... 4-3 4.3 U.S. RFG Specifications ...... 4-4 4.4 Propylene Yields from Steam Cracking ...... 4-5 4.5 Olefin Cracking Product Distribution...... 4-9

4.6 Comparison of Pentene Product Distribution from C2-C10 Hydrocarbons: Cracking vs. Equilibrium at 275°C (527°F) ...... 4-9

viii TABLES (Continued)

4.7 Conversion of Paraffins and Olefins over ZSM-5 at 1832°C (1000°F) ...... 4-11 4.8 Monomolecular vs. Bimolecular Mechanisms ...... 4-12 4.9 Monomolecular Olefin Cracking over ZSM-5...... 4-14 4.10 Aromatization of Light Hydrocarbons...... 4-22 6.1 Superflex and FCC Process Comparison...... 6-1 6.2 Superflex Catalyst Composition...... 6-2 6.3 Effects of Phosphorus and Steam on H-ZSM-5 ...... 6-4 6.4 Superflex Catalyst Circulation System...... 6-4 6.5 Superflex Process Reactor Yield: Single-Pass Mode...... 6-6 6.6 Effects of Recycle Ratio on the Superflex Process ...... 6-7 6.7 Superflex Process Reactor Yield: Recycle Mode ...... 6-7 6.8 Superflex Process Design Bases and Assumptions...... 6-10 6.9 Superflex Process Stream Flows...... 6-12 6.10 Superflex Process Major Equipment...... 6-13 6.11 Superflex Process Utilities Summary...... 6-15 6.12 Potential Propylene Production from an FCC/Superflex Complex ...... 6-16 6.13 Polypropylene Production from an FCC/Superflex Complex...... 6-17 6.14 Polymer-Grade Propylene Specifications ...... 6-19 6.15 Superflex Process Total Capital Investment ...... 6-21 6.16 Superflex Process Capital Investment by Section ...... 6-22 6.17 Superflex Process Production Costs ...... 6-23 7.1 MOI Process Reactor Yield ...... 7-4 7.2 Superflex Process Design Bases and Assumptions...... 7-7 7.3 MOI Process Stream Flows...... 7-9 7.4 MOI Process Major Equipment...... 7-10 7.5 MOI Process Utilities Summary...... 7-12

ix TABLES (Concluded)

7.6 Potential Propylene Production from an FCC/MOI Complex...... 7-13 7.7 Polypropylene Production from an FCC/MOI Complex ...... 7-15 7.8 Polymer-Grade Propylene Specifications ...... 7-16 7.9 MOI Process Total Capital Investment ...... 7-18 7.10 MOI Process Capital Investment by Section ...... 7-19 7.11 MOI Process Production Costs ...... 7-20 8.1 Alpha RFG Process ...... 8-2 8.2 Alpha ARO Process...... 8-2 8.3 Alpha Process Conditions...... 8-3 8.4 Alpha ARO Process Design Bases and Assumptions...... 8-7 8.5 Alpha Process Stream Flows...... 8-8 8.6 Alpha Process Major Equipment...... 8-12 8.7 Alpha Process Utilities Summary...... 8-14 8.8 Aromatics Production from the Alpha Process vs. Catalytic Reforming...... 8-15 8.9 Alpha Process Total Capital Investment ...... 8-18 8.10 Alpha Process Capital Investment by Section ...... 8-19 8.11 Alpha Process Production Costs ...... 8-21