ECONOMICS PROGRAM SRI INTERNATIONA Menlo Park, Califo Abstract Process Economics Program Report No. 149 ETHANOL FOR GASOHOL (March 1982) This report covers the production of ethanol from three major classes of biomass, viz., (1) the starch crop, represented by corn, (2) the sugar crop, represented by sugar beets, and (3) cellulosic materials, represented by wood. It reviews some of the methods to recover an anhydrous ethanol from a dilute aqueous solution, including a preliminary economic evaluation of a liquid carbon dioxide extraction method which is currently under pilot plant studies. It also presents some of the properties of gasohol (gasoline containing 10 ~01% ethanol). PEP'80 WSF
Report No. 1 49 ETHANOL FOR GASOHOL by WING SIEN FONG March 1982 A private report by the PROCESS ECONOMICS PROGRAM Menlo Park, California 94025
For detailed marketing data and information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMICAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PETROCHEMICALS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI DIRECTORY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States and Western Europe. ii
CONTENTS 1 INTRODUCTION.............,.....,...... 1 2 SUMMARY............................ 3 3 INDUSTRY STATUS........................ 13 Argentina... 14 Australia... 14 Brazil... 14 Europe..... 15 India... 16 Indonesia... 16 Japan... 16 Philippines.. 16 United States. 17 4 PROPERTIES OF GASOHOL... 23 Octane Number. 23 Volume Change. 27 Water Tolerance (Phase Separation)... 27 Vapor Pressure. 29 5 ETHANOL FOR GASOHOL FROM CORN................. 39 Chemistry... Hydrolysis of Starch.. Ethanol Fermentation... Process Review. Corn Processing... Starch Liquefaction and Saccharification (Hydrolysis).. Ethanol Fermentation... Stillage... Process Description... Corn Treatment and Starch Conversion. Fermentation. Ethanol Recovery and Dehydration... Distillers Dry Grain-Solubles (DDGS) Production. Process Discussion... Cost Estimates. 39 39 41 42 42 45 51 62 62 63 65 65 66 73 76 iii
CONTENTS 6 ETHANOL FOR GASOHOL FROM SUGAR BEETS. Chemistry.. Process Review Process Description... Beet Juice Production. Dry Beet Pulp Pellet Production.. Fermentation.... Ethanol Recovery and Dehydration. Distillers Dry Grain-Solubles (DDGS) Production Process Discussion... Cost Estimates 7 ETHANOL FOR GASOHOL FROM WOOD... Chemistry.. Process Review Dilute Sulfuric Acid Hydrolysis.. The Scholler-Tornesch Process.. The Madison Process. The TVA (or Modified Madison) Process... The Cederquist Process The American Can Process... The New York University Process. Finland Extrusion Process... Concentrated Hydrochloric Acid and (or) Hydrogen Chloride (Gas) Hydrolysis... The Bergius-Rheinau Process... The Flash Saccharification Process The Naguchi-Chisso Process... The Prodor Process.. The Hereng Process.. Concentrated Sulfuric Acid Hydrolysis... The Giordani-Leone Process... The Hokkaido Process. Wood Pretreatment... Steam Explosion... Steam-Extruder... Steam-Refiner... Batch-Steaming... Reprecipitation of Cellulose... High Energy Irradiation......... 85 85 86 91 93 93 93 94 94 101 103 115 115 123 123 123 125 126 127 127 128 128 129 129 130 131 131 132 132 132 133 133 133 134 134 135 135 136 iv
CONTENTS 7 ETHANOL FOR GASOHOL FROM FJOOD (Continued) Process Description... 136 Acid Hydrolysis of Wood 137 Lignin Recovery... 138 Fermentation... 138 Ethanol Recovery and Dehydration. 139 Yeast By-Product Recovery... 139 Process Discussion... 145 Cost Estimates... 149 8 RECOVERY OF ETHANOL FROM FERMENTED BROTH... 161 Introduction 161 Process Review... 161 Distillation... 162 Adsorption/Absorption. 166 Extraction 168 Other Processes... 171 Process Description... 171 Process Discussion... 177 Cost Estimates... 179 APPENDIX DESIGN AND COST BASES............... 187 CITED REFERENCES....................... 191 PATENT REFERENCES....................... 199 V
ILLUSTRATIONS 4.1 4.2 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Effect of Corn Price and Distillers' Dry Grain-Solubles (DDGS) Credit and Yield on the Net Production Cost...... 5.8 6.1 6.2 6.3 6.4 Effect of Ethanol Concentration on the Octane Number and Volume of Ethanol-Gasoline Blends,............ Effect of Ethanol Content on Gasoline's Reid Vapor Pressure...................... A Typical Wet Milling Process for Corn............ Typical Dry Milling Processes for Corn,........... Archer Daniels Midland Ethanol Batch Process......... Archer Daniels Midland Continuous Anhydrous Ethanol Process........................ Alfa-Lava1 "Biostil" Process................. FlowSheet.......................... Effect of Operating Level and Plant Capacity on Production Cost.......,.............. A Block Flow Diagram for a Typical Process to Produce Ethanol from Sugar Beets.............. Ethanol for Gasohol from Sugar Beets FlowSheet.......................... Ethanol for Gasohol from Sugar Beets Effect of the Production Schedules of Beet Juice and Dry Beet Pulp Pellet on the Total Fixed Capital and Net Production Cost.................... Ethanol for Gasohol from Sugar Beets Effect of Sugar Beet Price and By-Products (Beet Pulp Pellet and DDGS) Credit and Yield on Net Production Cost............ 28 30 43 46 55 56 60 201 33 84 87 205 109 113 vii
ILLUSTRATIONS 6.5 Ethanol for Gasohol from Sugar Beets Effect of Operating Level and Plant Capacity on Production Cost,..,.....,............ 114 7.1 Ethanol for Gasohol from Wood Flow Sheet......................... 209 7.2 Ethanol for Gasohol from Wood Effect of Wood Price, Lignin Credit and Yeast By-Product Credit on the Net Production Cost............., 157 7.3 Ethanol for Gasohol from Wood Effect of Operating Level and Plant Capacity on Production Cost...................... 158 7.4 Ethanol for Gasohol from Wood Effect of Disposal Charge or Credit for the By-Product Calcium Sulfate and Residual Hexosans, Pentosans, and Sugars in the Stillage on the Net Production Cost,,.... 159 8.1 Distribution Coefficients for Normal Aliphatic Alcohols in Carbon Dioxide/Water Mixture............... 170 8.2 Ethanol Recovery by Liquid Carbon Dioxide Extraction FlowSheet.. 213 8.3 Ethanol Recovery by Liquid Carbon Dioxide Extraction Effect of the Pressure of the Recycling Carbon Dioxide Streams on the Battery Limits Investment and Total Direct Operating Costs..............,.. 184 8.4 Ethanol Recovery by Liquid Carbon Dioxide Extraction Effect of the Size of the Extraction Column on the Battery Limits Investment and Total Direct Operating Costs................. 185 8.5 Ethanol Recovery by Liquid Carbon Dioxide Extraction Effect of Makeup Carbon Dioxide Requirement or Price on the Total Direct Operating Costs............. 186 Viii
TABLES 2.1 2.2 3.1 3.2 4.1 4.2 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 6.1 6.2 Summary of Economics for Production of Ethanol from Corn, Sugar Beets, and Wood.............. 9 Summary of Economics for Recovery of Ethanol from a Fermented Broth by Distillation and Liquid Carbon Dioxide Extraction........,... 10 State Tax Incentives for Gasohol in the United States.......,,........... 19 Potential and Existing Ethanol-For-Gasohol Producers in the United States and Their Existing and (or) Planned Capacities.,................... 20 Some Physical Properties of Ethanol and Gasoline...... 24 Effect of Ethanol Content on Some of the Physical-Chemical Properties of a Gasoline......... 25 Bases and Assumptions.................... 64 Stream Flows........................ 68 Major Equipment....,................. 69 Utilities Summary...................,.. 72 Total Capital Investment.................. 78 Capital Investment by Section................ 79 Production Costs...................... 80 Direct Operating Costs by Section......,....... 82 Ethanol for Gasohol from Sugar Beets Bases and Assumptions.................... 92 Ethanol for Gasohol. from Sugar Beets Stream Flows.... e................... 96 ix
TABLES 6.3 Ethanol for Gasohol from Sugar Beets Major Equipment,..................... 97 6.4 Ethanol for Gasohol from Sugar Beets Utilities Summary..................... 100 6.5 Ethanol for Gasohol from Sugar Beets Total Capital Investment.................. 107 6.6 Ethanol for Gasohol from Sugar Beets Capital Investment by Section............... 108 6.7 Ethanol for Gasohol from Sugar Beets Production Costs..................... 110 6.8 Ethanol for Gasohol from Sugar Beets Direct Operating Costs by Section............. 112 7.1 Typical Composition of Wood (Extractives and Ash-Free Basis)............. 117 7.2 Some Reaction Rate Constants for the Hydrolysis of Douglas Fir Cellulose.,........ 120 7.3 Some Reaction Rate Constant Ratios for Cellulose Hydrolysis and Glucose Decomposition.,.. 122 7.4 Ethanol for Gasohol from Wood Bases and Assumptions................... 140 7.5 Ethanol for Gasohol from Wood StreamFlows....................... 141 7.6 Ethanol for Gasohol from Wood Major Equipment...................... 142 7.7 Ethanol for Gasohol from Wood Utilities Summary.................... 148 7.8 Ethanol for Gasohol from Wood Total Capital Investment................. 152 7.9 Ethanol for Gasohol from Wood Capital Investment by Section............,.. 153 7.10 Ethanol for Gasohol from Wood Production Costs..................... 154 7.11 Ethanol for Gasohol from Wood Direct Operating Costs by Section............. 156 ' X
TABLES 8.1 Ethanol Recovery by Liquid Carbon Dioxide Extraction Bases and Assumptions................... 172 8.2 Ethanol Recovery by Liquid Carbon Dioxide Extraction Stream Flows....................... 174 8.3 Ethanol Recovery by Liquid Carbon Dioxide Extraction Major Equipment...................... 175 8.4 Ethanol Recovery by Liquid Carbon Dioxide Extraction Utilities Summary..................... 176 8.5 Ethanol Recovery by Liquid Carbon Dioxide Extraction Capital Investment Estimate......,.,....... 182 8.6 Ethanol Recovery by Liquid Carbon Dioxide Extraction Direct Operating Costs............,..... 183 Xi