Abstract Process Economics Program Report 252 CHEMICALS FROM AGRICULTURAL WASTES (September 2004)

Transcription

1 Abstract Process Economics Program Report 252 CHEMICALS FROM AGRICULTURAL WASTES (September 2004) Petrochemical hydrocarbon sources are finite and many experts suggest that they will become exhausted within decades. In addition, both natural gas and crude oil have recently experienced an upward shift in pricing trends. The use of bio-based sources such as plant/crop wastes provides inputs that are renewable and creates the opportunity for a transition to a more sustainable economy. There is also the hope that in the near future, cellulosic plant/crop wastes will become economically competitive with petrochemical feedstocks. There are numerous challenges, both technical and infrastructure related, associated with commercializing lignocellulosics as feedstocks for chemicals. While large quantities of various crop wastes go unused throughout the world, these lignocellulosic materials are difficult to efficiently convert into chemical products due to their complex polymeric structures. A multi-disciplinary approach that couples biotechnology and chemistry with process engineering is necessary in order to achieve efficient commercial processes. In addition to the technical challenges of commercializing this technology, there are also large infrastructure barriers. These barriers are associated with the development of new agricultural infrastructure for the collection and storage of crop wastes. An integrated feedstock supply system must be developed that can supply the feedstock needs in a sustainable fashion at a reasonable cost. Infrastructure issues could be as important as the technical issues when considering overall production costs. In this report, PEP presents process designs and associated cost estimates for the production of two chemicals, ethanol and lactic acid, from agricultural wastes. Technology development is in the semi-commercial stage in North America, Europe and Japan for economically producing fuel grade ethanol from a crop waste such as corn stover, wheat straw or rice straw. Process economics are also estimated for producing lactic acid from corn stover, a technology that is more recently under development. Ultimately, the best process economics for the use of these feedstocks could come through the development of the biorefinery, a concept also discussed in this report. For lignocellulosic biomass to be economically viable as an ethanol feedstock, the Department of Energy has chosen a target ethanol selling price of $1.07 per gallon (28 per liter) as a goal for Our PEP analysis indicates that more progress must be made in biomass conversion technology to meet that goal. Our PEP analysis of lactic acid production from corn stover indicates a good potential for manufacturing the chemical profitably at prices significantly below current market prices. Corn stover has a good potential as a lactic acid feedstock after conversion technology has been demonstrated at the commercial scale for producing ethanol. For those in the chemical industry, this report will be useful for the comparative economics it provides, as well as for its extensive review of ongoing research related to biomass conversion technologies. The report reviews and analyzes more than 200 recent patents and articles related to biomass conversion. The report s review of biomass availability around the world will also be useful for those exploring this field. PEP 04 GMB

2 R eport No. 252 C HE MIC A L S F R OM A R G IC UL T UR A L WA S T E S by G R E G M B OHL MA NN S eptember 2004 A private report by the P R OC E S S E C ONOMIC S P R OG R A M SR I Menlo P ark, C alifornia 94025

3 SRIC agrees to assign professionally qualified personnel to the preparation of the Process Economics Program s reports and will perform the work in conformance with generally accepted professional standards. No other warranties expressed or implied are made. Because the reports are of an advisory nature, neither SRIC nor its employees will assume any liability for the special or consequential damages arising from the Client s use of the results contained in the reports. The Client agrees to indemnify, defend, and hold SRIC, its officers, and employees harmless from any liability to any third party resulting directly or indirectly from the Client s use of the reports or other deliverables produced by SRIC pursuant to this agreement For detailed marketing data and information, the reader is referred to one of the SRI Consulting 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 SRIC DIRECTORY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States, Western Europe, Canada, and East Asia, South America and Mexico.

4 CONTENTS 1 INTRODUCTION SUMMARY BIOMASS FEEDSTOCKS ETHANOL STATUS LACTIC ACID STATUS TECHNICAL ASPECTS Ethanol from Corn Stover Lactic Acid from Corn Stover Biorefinery Case Study ECONOMIC ASPECTS INDUSTRY STATUS INTRODUCTION GOVERNMENT POLICY AND LEGISLATION RENEWABLES VISION ETHANOL LACTIC ACID Lactic Acid Pricing BIOMASS FEEDSTSOCKS BIOMASS AVAILABILITY Corn Stover Wheat Straw FOREST CROPS Wood and Paper Wastes Rice Straw iii

5 CONTENTS (Continued) 5 CONVERSION TECHNOLOGIES PROCESS REVIEW Pretreatment/Prehydrolysis Saccharification Co-Fermentation LACTIC ACID Fermentation Traditional Recovery Recovery by Extraction Base Regeneration Purification Recombinant Lactobacillus ETHANOL PROCESS DESCRIPTION Pretreatment and Conditioning Saccharification and Co-Fermentation Distillation and Dehydration PROCESS DISCUSSION NREL Design Feedstock On-Stream Factor Waste Treatment Materials of Construction CAPITAL AND PRODUCTION COSTS DISCUSSION OF PRODUCT VALUE vi

6 CONTENTS (Continued) 7 LACTIC ACID PROCESS DESCRIPTION Pretreatment and Conditioning Saccharification and Co-Fermentation Extraction and Purification PROCESS DISCUSSION Fermentation Productivity Selection of Extraction Design Patents Product Quality Waste Treatment Materials of Construction CAPITAL AND PRODUCTION COSTS DISCUSSION OF CAPITAL COST AND PRODUCT VALUE BIOREFINERY CONCEPT LIGNOCELLULOSE BIOREFINERY WHOLE CROP BIOREFINERY GREEN BIOREFINERY BIOREFINERY CASE STUDY Section 100 Pretreatment and Conditioning Section 200 Saccharification and Co-Fermentation Section 300 Distillation and Dehydration Section 400 Dry Mill and Saccharification Section 500 Fermentation Section 600 Recovery and Purification Section 700 DDGS Recovery vii

7 CONTENTS (Concluded) Section 800 Combustion and Turbogeneration Capital Costs APPENDIX A: PATENT SUMMARY TABLES... A-1 APPENDIX B: DESIGN AND COST BASES... B-1 APPENDIX C: CITED REFERENCES... C-1 APPENDIX D: PROCESS FLOW DIAGRAMS... D-1 viii

8 ILLUSTRATIONS 3.1 U.S. Chemical Industry Purchases Oil and Natural Gas Prices World Ethanol Production Corn Wet Milling and Dry Milling U.S. Ethanol Prices Cumulative U.S. Biomass Quantities by Price Commodity Price Projections The Effect of Plant Size on Collection Distance Major Components of Plant Materials Schematic Diagram of the Conversion of Biomass Feedstock to Ethanol Fuel Carbohydrates Dilute Acid Production of Hemicellulose Syrups Ethanol from Rice Straw by Arkenol Technology Bioethanol Production Using Fungal Pretreatment Hot Wash Effect on Simultaneous Saccharification and Fermentation Yield Corn Stover Hemicellulose Syrup Fermentation Modified Zymomonas Mobilis Pathway Prodigene Process for Production of Ethanol from Corn Stover The Embden-Meyerhof-Parnas Catabolism Pathway Lactic Acid Effect on Enzymatic Hydrolysis of Cellulose Lactic Acid from Lignocellulosic Feedstocks Lactic Acid from Wastepaper vs. Glucose Simultaneous Saccharification and Extractive Fermentation Ethanol from Biomass Processes The Effect of Plant Size on Collection Distance viii

9 ILLUSTRATIONS (Concluded) 6.3 Ethanol from Corn Stover... D Lactic Acid from Corn Stover... D Biorefinery Building Blocks and Intermediates Ligno-Cellulosic Feedstock Biorefinery [LCF-Biorefinery] Integrated Biorefinery Model Green Biorefinery Biorefinery Case Study Ethanol and 1,3-Propanediol from Whole Corn ix

10 TABLES 2.1 Chemicals from Agricultural Wastes Manufacturing Cost Summary DOE/USDA Awards Wet Milling vs Dry Milling Major U.S. Ethanol Producers Proposed Cellulose to Ethanol Plants in the United States Primary Producers of Lactic Acid Lactic Acid Prices in Three Geographic Regions Available Waste Biomass in the United States Potential Bioethanol Production Major Energy Inputs for Selected Crops Corn and Stover Production in Estimated Costs for Corn Stover Harvest Cost Variation Under Low and High Resource Availability Facility Size = 2,000 Dry Tons/Day One Pass Harvest and Rail System Economics Corn and Stover Compositions Corn Stover Composition Range % Dry Weight Basis Wheat Straw Availability Chemical Composition of Wheat Straw Composition of American and European Oaks California Rice Straw Composition Cost Estimate for Rice Straw Pretreatment Processes Patent Summary... A Effect of 121 C Pretreatment on Different Feedstocks Comparison of Pretreatment Processes Cellulase Enzyme Requirements for Various Feedstocks xi

11 TABLES (Continued) 5.5 Saccharification and Fermentation Patent Summary... A Recombinant Saccharomyces Performance at 9000 Liters Microorganism Performance in the Presence of Lignocellulose Sugars Effect of ph on Lactic Acid Separation Representative Prices for Biomass and Fossil Resources Theoretical Ethanol Yields Ethanol from Corn Stover Design Bases Ethanol from Corn Stover Stream Flows Ethanol from Corn Stover Major Equipment Ethanol from Corn Stover Utilities Summary Pretreatment Hydrolyzer Reactions and Conversions Saccharification Reactions and Conversions Ethanol from Corn Stover Total Capital Investment Ethanol from Corn Stover Capital Investment by Section Ethanol from Corn Stover Production Costs Ethanol from Corn Stover Direct Costs by Section, $ thousands/yr Production Costs of Bioethanol in Brazil Lactic Acid from Various Fermentation Substrates Lactic Acid from Corn Stover Design Bases Lactic Acid from Corn Stover Stream Flows xii

12 TABLES (Concluded) 7.4 Lactic Acid from Corn Stover Major Equipment Lactic Acid from Corn Stover Utilities Summary Pretreatment Hydrolyzer Reactions and Conversions Saccharification Reactions and Conversions Lactic Acid from Corn Stover Total Capital Investment Lactic Acid from Corn Stover Capital Investment by Section Lactic Acid from Corn Stover Production Costs Lactic Acid from Corn Stover Direct Costs by Section, $ thousands/yr Capital Related Elements at Plant Capacity 400 Million lb/yr Sugar from Corn Stover Whole Corn Biorefinery Battery Limits Investment Whole Corn Biorefinery Total Capital Investment Whole Corn Biorefinery Production Costs PDO Economic Comparison xiii