Abstract Process Economics Program Report 262 PROPYLENE GLYCOL FROM GLYCERIN (December 2007)

Abstract Process Economics Program Report 262 PROPYLENE GLYCOL FROM GLYCERIN (December 2007) A variety of economic, environmental and technical factors have encouraged industry attention on producing industrial chemicals from bio-feedstocks, rather than from crude oil derivatives. One such example is producing propylene glycol (PG) from glycerine (GLY), rather than the conventional routes starting with propylene monomer. Propylene glycol has historically been produced in commercial quantities either via the chlorohydrin process or by peroxidation, both using propylene monomer as the starting material. Both routes produce propylene oxide (PO) as an intermediate chemical, which is then hydrated to propylene glycol. The peroxidation routes have evolved from those processes (Arco Chem/Lyondell, Repsol, Shell, BASF) producing a significant amount of by-product (PO/styrene monomer, PO/tertiary butyl alcohol, PO/ methyl tertiary butyl ether), to more recent processes developed by Solvay, Dow and BASF that eliminate the by-product by using hydrogen peroxide as the oxidizing agent. As of 2007, Degussa has announced the design and construction of a commercial scale PG plant using glycerine as its feedstock. Other companies have announced processes to use glycerine to produce polyols and epichlorohydrin. The combination of high crude oil prices and governmental subsidies to produce biofuels (bio-ethanol, bio-diesel) have resulted in an enormous increase in bio-diesel production, resulting in a glut of by-product glycerine (which represents 10% of biodiesel mass). As a result, glycerine market prices have fallen from $US 2/kg down to fuel value ($US 200/mt), or less. The low cost of glycerine combined with the high price of PG offers an opportunity to develop industrial scale processes converting glycerine to propylene glycol. This report presents preliminary process engineering design information and the corresponding production economics for converting GLY to PG using the Davy process and a process developed at the University of Missouri by Galen Suppes. In addition to these two processes this report also provides a detailed design of the glycerin purification section that is needed to allow these processes to take advantage of lower cost crude glycerin which is readily available form may bio-diesel production facilities. SRI Consulting PEP Report 262

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CONTENTS 1 INTRODUCTION... 1-1 SOURCE OF GLYCERIN FROM BIO-DIESEL MANUFACTURE... 1-2 ALTERNATIVE COMMERCIAL ROUTES TO PG VIA PO... 1-3 VALUE PROPOSITION FOR PROPYLENE GLYCOL FROM GLYCERIN... 1-6 2 SUMMARY... 2-1 UPGRADING FUEL GRADE GLYCERIN... 2-2 AVAILABLE LICENSED TECHNOLOGIES... 2-3 KEY TECHNOLOGY ATTRIBUTES... 2-3 ATTRACTIVENESS OF GLYCERIN TO PROPYLENE GLYCOL... 2-3 3 PROCESS SAFETY... 3-1 PROCESS SAFETY CONCERNS... 3-1 MAJOR SAFETY CONCERN FOR PG FROM GLY... 3-1 PRODUCT SAFETY CHARACTERISTICS OF PROPYLENE GLYCOL AND GLYCERIN... 3-1 Glycerin... 3-2 Hydrogen... 3-3 Acetol... 3-3 Acrolein... 3-3 Propylene Glycol... 3-4 Ethylene Glycol... 3-4 Methanol... 3-5 CATALYSTS... 3-5 BRIEF PROCESSING PERKS... 3-6 MAJOR PROCESSING RISKS... 3-6 MATERIALS OF CONSTRUCTION... 3-6 SRI Consulting iii PEP Report 262

CONTENTS (Continued) 4 VALUE PROPOSITION FOR CONVERTING GLYCERIN TO PROPYLENE GLYCOL... 4-1 HISTORICAL PRICING ENVIRONMENT... 4-1 GLYCERIN PRODUCTION LEVEL FROM BIO-DIESEL... 4-4 SUBSIDY ECONOMICS FOR BIO-DIESEL... 4-5 LONG TERM VIABILITY OF METHYL ESTER BIO-DIESEL... 4-6 BIO-DIESEL FEEDSTOCK OPTIONS... 4-8 ALTERNATE CHEMISTRIES FOR CONSUMING GLYCERIN... 4-9 5 INDUSTRY STATUS... 5-1 PROPYLENE GLYCOL... 5-1 PG--Physical Properties... 5-1 PG--Chemical Properties... 5-2 PG--Uses... 5-2 PG--Integrated Supply Chain... 5-3 PG--Commercial Grades... 5-4 PG--Methods of Manufacture... 5-5 PG--SUPPLY AND DEMAND... 5-5 PG--DEMAND GROWTH... 5-7 PG--By-Product Production... 5-7 PG--COMPETITORS... 5-8 HISTORICAL PRICES FOR PROPYLENE GLYCOL... 5-11 GLYCERIN... 5-14 Glycerin Physical Properties... 5-14 Glycerin Chemical Properties... 5-15 COMMERCIAL USES FOR GLYCERIN... 5-15 PRODUCTION OF GLYCERIN... 5-16 SRI Consulting iv PEP Report 262

CONTENTS (Continued) GLOBAL GLYCERIN SUPPLY/DEMAND BALANCE... 5-17 COMMERCIAL GRADES OF GLYCERIN... 5-19 CRUDE GLYCERIN... 5-19 Refined or Purified Glycerin... 5-20 Commercial Uses for Glycerin... 5-21 Historical Glycerin Pricing... 5-21 BALANCE BETWEEN CRUDE GLYCERIN AND REFINED GLYCERIN... 5-25 QUANTITY OF EXCESS GLYCERIN PRODUCTION VIA BIO-DIESEL... 5-26 POSSIBLE NEW COMMERICAL CHEMICALS FROM GLYCERIN... 5-28 ANNOUNCED PROJECTS FOR PROPYLENE GLYCOL FROM GLYCERIN... 5-29 OTHER COMMERICAL PRODUCT ANNOUNCEMENTS INVOLVING GLYCERIN AS FEEDSTOCK... 5-30 Epichlorohydrin... 5-30 Propane Diol (PDO)... 5-30 Glycerine Based Polyols... 5-30 Other Commercial Product Announcements Involving Propylene Glycol Production from Bio-Feedstocks... 5-31 6 RELEVANT CHEMISTRY... 6-1 GLYCERIN MOLECULAR STRUCTURE... 6-1 CONVENTIONAL SOURCES OF GLYCERIN... 6-1 FORMATION OF GLYCERIN BY-PRODUCT FROM BIO-DIESEL PRODUCTION. 6-2 SAPONIFICATION... 6-2 CHEMISTRY OF PROPYLENE GLYCOL PRODUCTION FROM GLYCERIN... 6-3 CONVENTIONAL CATALYSTS FOR GLYCERIN CONVERSION TO PROPYLENE GLYCOL... 6-4 HYDROGENOLYSIS CATALYSTS... 6-4 COMPETING REACTIONS... 6-5 SRI Consulting v PEP Report 262

CONTENTS (Continued) SELECTIVE DEOXYGENATION... 6-5 CHEMISTRY FOR CONVENTIONAL PROPYLENE GLYCOL PRODUCTION... 6-6 7 PROCESS DESIGN BASIS... 7-1 DESIGN CONDITIONS... 7-1 SITE LOCATION... 7-1 FACILITY SITE BASIS... 7-2 Cost Bases... 7-2 Capital Investment... 7-2 CONSTRUCTION CAPITAL COST INDEX... 7-4 PROJECT CONSTRUCTION TIMING... 7-6 PRODUCTION COSTS... 7-6 Effect of Operating Level on Production Costs... 7-6 BASIC BIO-DIESEL PROCESS... 7-7 PRE-TREATMENT OF GLYCERIN WITHIN BIO-DIESEL PLANT... 7-8 MATERIALS OF CONSTRUCTION FOR FUEL GRADE GLYCERIN PROCESSING AND STORAGE... 7-13 DESIGN BASIS RATIONALE FOR GLYCERIN PRE-TREATMENT IN PROPYLENE GLYCOL PLANT... 7-14 MATERIALS OF CONSTRUCTION FOR PROPYLENE GLYCOL PROCESSING FROM GLYCERIN... 7-14 SYNTHETIC PRODUCTION OF GLYCERIN... 7-15 DESIGN BASIS FOR PLANT UTILITY FUEL... 7-15 DESIGN BASIS FOR PLANT PRODUCTION CAPACITY... 7-15 PROCESS PLANT PRODUCT SPECIFICATIONS... 7-16 Propylene Glycol Product Specifications... 7-16 METHANOL BY-PRODUCT SPECIFICATIONS... 7-16 PROCESS PLANT FEEDSTOCK SPECIFICATIONS... 7-17 SRI Consulting vi PEP Report 262

CONTENTS (Continued) Glycerin Purity Required for Propylene Glycol Production... 7-17 Fuel Grade Glycerin Specifications... 7-18 Glycerin Analytical Standards... 7-18 8 PRE-TREATMENT OF FUEL GRADE GLYCERIN... 8-1 RATIONALE FOR PRE-TREATMENT... 8-1 SCOPE OF WORK FOR PRE-TREATMENT SYSTEM... 8-3 INPUT-OUTPUT DIAGRAM... 8-4 BIO-DIESEL PROCESS PRIMER... 8-4 CHARACTERIZATION OF FUEL GRADE GLYCERIN... 8-5 FUEL GRADE GLYCERIN COMPOSITION... 8-6 COMPOSITION OF PRE-TREATED GLYCERIN... 8-8 GLYCERIN PRE-TREATMENT UNIT PROCESSING... 8-8 PRE-TREATMENT BLOCK FLOW DIAGRAM... 8-9 PROCESS DESIGN BASIS FOR FUEL GRADE GLYCERIN RECEIVING AND BULK STORAGE FACILITIES... 8-11 PROCESS DESCRIPTION: UNLOADING AND BULK STORAGE OF CRUDE GLYCERIN... 8-11 FUEL GRADE GLYCERIN NEUTRALIZATION... 8-12 FEEDSTOCK HEATING AND FREE OIL SEPARATION... 8-12 CENTRIFUGE FILTRATION AND ION EXCHANGE BEDS... 8-12 WIPED FILM VACUUM EVAPORATION... 8-13 FINAL GLYCERIN VACUUM DISTILLATION... 8-14 ACTIVATED CARBON TREATMENT... 8-15 METHANOL PURIFICATION SYSTEM... 8-15 9 PROPYLENE GLYCOL FROM GLYCERIN VIA DAVY VAPOR PHASE PROCESS TECHNOLOGY... 9-1 SRI Consulting vii PEP Report 262

CONTENTS (Continued) LIQUID AND VAPOR PHASE PROCESSES... 9-1 ASHLAND-CARGILL PG PROJECT ANNOUNCEMENT... 9-1 DAVY LIQUID PHASE PROCESS TECHNOLOGY... 9-1 Liquid Phase Process Configuration... 9-2 Documented Basis for Davy Liquid Phase Design... 9-2 CLAIMED BENEFITS OF THE DAVY LIQUID PHASE PROCESS... 9-2 KEY ELEMENTS OF DAVY VAPOR PHASE GLYCERIN TO PG TECHNOLOGY.. 9-3 Qualitative Evaluation of the Davy Vapor Phase Process... 9-4 DAVY VAPOR PHASE PROCESS CATALYST... 9-4 Reactor Design Conditions... 9-4 PROCESS DESCRIPTION OF DAVY VAPOR PHASE PROCESS... 9-5 10 PROPYLENE GLYCOL FROM GLYCERIN VIA PROFESSOR SUPPES TECHNOLOGY... 10-1 TECHNOLOGY LICENSING... 10-1 Essence of Suppes Process... 10-2 USE OF COPPER-CHROMITE CATALYST... 10-2 Impact of Water on Reaction... 10-3 Impact of Reactive Distillation... 10-3 Documentation Used in the Process Design... 10-4 PROCESS DESCRIPTION... 10-4 OPPORTUNITY TO PRODUCE PG FREE OF EO... 10-5 11 RELEVANT US PATENTS... 11-1 Hydrogenation of Benzene to Toluene... 10-10 Hydrogenation of Benzene to Toluene... 10-22 Hydrogenation of Benzene to Toluene... 10-33 SRI Consulting viii PEP Report 262

CONTENTS (Concluded) APPENDIX A: PATENT SUMMARY TABLES... A-1 APPENDIX B: CITED REFERENCES... B-1 APPENDIX C: PROCESS FLOW DIAGRAM... C-1 SRI Consulting ix PEP Report 262

ILLUSTRATIONS 1.1 Glycerin Molecular Structure... 1-1 1.2 Chemistry of Glycerin Conversion to Propylene Glycol... 1-2 1.3 3-Step Process: Propylene Glycol from Glycerin... 1-2 1.4 Bio-Diesel Chemistry... 1-3 1.5 PO Hydration to PG... 1-3 1.6 Propylene Glycol Integrated Product Chain... 1-4 2.1 Glycerin Pre-Treatment Sequence... 2-2 4.1 Historical US Naphtha and Propylene Prices... 4-1 4.2 Historical US Price for Glycerin... 4-2 4.3 Historical US PO and PG Price... 4-3 4.4 Historical US Prices for Propylene and PG... 4-3 4.5 Historic US Prices for Glycerin and PG... 4-4 4.6 Methyl Ester vs. Hydrogenated Bio-Diesel... 4-7 5.1 Uses for Propylene Glycol... 5-3 5.2 Propylene Glycol Integrated Product Chain... 5-3 5.3 Propylene Oxide Derivatives... 5-4 5.4 Hydration of PO to PG... 5-7 5.5 Western Europe Sourcing for Glycerin... 5-17 5.6 Historic US Crude Glycerin Prices... 5-22 5.7 Historic Refined Glycerin Prices... 5-22 5.8 World Bio-Diesel Production by Region and Consumption of Biodiesel... 5-27 5.9 World Biodiesel Production Capacity and Supply/Demand... 5-28 6.1 Molecular Structure of Glycerin... 6-1 6.2 Reaction Paths for Triglycerides... 6-2 6.3 Methanol Reaction with Triglycerides... 6-2 6.4 Glycerin Conversion to PG... 6-3 6.5 Glycerin Conversion Pathways... 6-6 SRI Consulting x PEP Report 262

ILLUSTRATIONS (Concluded) 6.6 Hydration of PO to PG... 6-6 7.1 Historical PEP Construction Cost Index for the U.S. Gulf Coast... 7-4 7.2 Basic Bio-Diesel Production Process... 7-8 7.3 Block Flow Diagram of By-Product Glycerin Treatment within Bio-Diesel Production Plant... 7-10 8.1 Schematic of Lurgi Bio-Diesel Plant... 8-2 8.2 Segmentation of Glycerin to PG Process... 8-3 8.3 Process Input/Output Diagram... 8-4 8.4 Block Flow Diagram for Glycerin Pre-Treatment... 8-10 8.5 Glycerin Pre-Treatment Process Flow Diagram... C-3 9.1 Propylene Glycol from Glycerine via Davy Vapor Phase Technology Process Flow Diagram... C-9 10.1 Reaction Steps in Suppes Process... 10-2 10.2 PG from Glycerine via Suppres Liquid Phase Technology... C-11 SRI Consulting xi PEP Report 262

TABLES 2.1 Commercial Uses for Glycerin... 2-1 3.1 Major Product Safety Risks... 3-2 4.1 Global Production of Glycerin by Source (KTY)... 4-5 4.2 Green Diesel Yield... 4-7 4.3 Comparison of Diesel Fuels... 4-8 4.4 Potential Farm Yield of Bio-Diesel Feedstock Sources... 4-9 5.1 Boiling Point Elevation with PG:H 2 O Solutions... 5-1 5.2 Freezing Point Depression with PG:H 2 O Solutions... 5-1 5.3 Heat Capacity of PG:H 2 O Solutions... 5-2 5.4 Commercial Specifications for Propylene Glycol... 5-4 5.5 Global Propylene Glycols Capacity and Consumption 2006... 5-6 5.6 World Supply/Demand for Propylene Glycols 2006... 5-7 5.7 Major World Producers of Propylene Glycols... 5-8 5.8 World Producers of Propylene Glycols... 5-9 5.9 U.S. List Price and Unit Value for Monopropylene Glycol... 5-12 5.10 Western European Prices for Propylene Glycols... 5-13 5.11 Historical Japan Prices for PG... 5-14 5.12 Physical Properties of Purified Glycerin... 5-15 5.13 Commercial Uses for Glycerin... 5-16 5.14 Glycerin Global Supply/Demand Balance... 5-18 5.15 Commercial Grades of Glycerin... 5-19 5.16 Forms of Crude Glycerin... 5-20 5.17 Forms of Refined Glycerin... 5-20 5.18 Historic US Glycerin Prices... 5-23 5.19 Historic European Glycerin Prices... 5-24 5.20 Historic Japan Glycerin Prices... 5-25 5.21 SRIC Projection of World Bio-Diesel Production by Region... 5-26 SRI Consulting xii PEP Report 262

TABLES (Continued) 7.1 Construction Cost Site Location Factors... 7-1 7.2 Historical PEP Construction Cost Index for the U.S. Gulf Coast... 7-5 7.3 Distribution of Components from Raw Bio-Diesel Decanting Drum... 7-11 7.4 Combined Glycerin Rich Streams from Bio-Diesel Manufacturing Plant... 7-11 7.5 Feed Stream to Methanol Recovery within Bio-Diesel Manufacturing Plant... 7-12 7.6 Representative Composition of Fuel Grade Glycerin Stream from Medium Scale Bio-Diesel Plant... 7-13 7.7 Propylene Glycol Product Specifications... 7-16 7.8 Methanol By-Product Specification... 7-17 7.9 Pre-Treated Glycerin Specification... 7-18 8.1 Fuel Grade Glycerin Composition from Bio-Diesel Plant that Recovers Methanol...8-7 8.2 Fuel Grade Glycerin Composition from Bio-Diesel Plant that Does Not Recover Methanol... 8-7 8.3 Composition of Pre-Treated Glycerin... 8-8 8.4 Process Conditions for Wiped Film Evaporators... 8-14 8.5 Utility Consumption of Lurgi Glycerin Distillation Unit... 8-14 8.6 Pre-Treatment Section Material Balance... 8-16 8.7 Technical Grade Glycerin from Fuel Grade Glycerin Equipment List... 8-17 8.8 Technical Grade Glycerin from Fuel Grade Glycerin Total Capital Investment... 8-19 8.9 Technical Grade Glycerin from Fuel Grade Glycerin Production Economics... 8-20 9.1 Propylene Glycol from Glycerin via Davy Vapor Phase Technology Material Balance... 9-7 9.2 Propylene Glycol from Glycerin via Davy Vapor Phase Technology Equipment List... 9-8 9.3 Propylene Glycol from Glycerin via Davy Vapor Phase Technology Capital Cost Estimate... 9-10 SRI Consulting xiii PEP Report 262

9.4 Propylene Glycol from Glycerin via Davy Vapor Phase Technology Production Economics... 9-11 TABLES (Concluded) 10.1 Catalyst Results for the Suppes Process... 10-3 10.2 Propylene Glycol from Glycerin via Suppes Liquid Phase Technology Material Balance... 10-6 10.3 Propylene Glycol from Glycerin via Suppes Liquid Phase Technology Equipment List... 10-7 10.4 Propylene Glycol from Glycerin via Suppes Liquid Phase Technology Capital Cost Estimate... 10-9 10.5 Propylene Glycol from Glycerin via Suppes Liquid Phase Technology Production Cost Estimate... 10-10 SRI Consulting xiv PEP Report 262