Published on January 7, 2008
Bioenergy from Food Waste and Farm Grown Crops: Bioenergy from Food Waste and Farm Grown Crops David Specca, Acting Director Rutgers EcoComplex Slide2: EcoComplex Office, Lab and Outreach Center Slide3: Solid Waste Management Water Quality Renewable Energy Controlled Environmental Ag. Landfill Gas Use Organics Recycling Green Purchasing Anaerobic Digestion Surface Water Lab Storm Water Management Impervious Cover Issues Non-point source pollution TMDL’s LFG/Biogas Biodiesel Ethanol Hydrogen Biomass Gasification Hydroponics Aquaculture Vermiculture Energy efficiency Program Areas Research and Demonstration Greenhouse: Research and Demonstration Greenhouse Over one acre of greenhouse laboratory, hydroponics and aquaculture facilities Slide5: A range of biomass resources were examined; these can be divided into 5 categories based on their physical characteristics. 500 pound-per-day Food WasteAnaerobic Digester Demonstration – Nearing Completion: 500 pound-per-day Food Waste Anaerobic Digester Demonstration – Nearing Completion Slide7: Anaerobic Digestion Process Four main microbial steps of the AD process: Hydrolytic bacteria break down organic materials into sugars and amino-acids Fermentative bacteria convert these into organic acids Acidogenic bacteria convert acids into CO, H2 and acetate Methanogenic archea convert these into methane In the two phase digesters, the acidogenic and methanogenic micro-organisms operate in separate tanks in optimum environments. The first tank can be also pressurized to achieve fast hydrolysis. The benefits are: Lower capital costs due to smaller tanks Ability to process higher solid content material 30% higher biomass conversion rates Higher methane content and cleaner biogas Reduced pathogen content in the digestate solids Other interesting process improvements include: Innovative flow designs that enable higher hydraulic and solid retention times (HRT, SRT) such as the Valorga process Biomass pre-treatment done to break down the lignin, increasing biodegradability and yield The use of microorganisms that work at higher (thermophilic) temperatures allows for lower retention times. Process parameters are sensitive and more diligent operations are required. Anaerobic Digestion process description. Biomass / Water / Chemicals Shredding, Blending, PH adjustment Pre-treatment Digester Gas Clean-up Digester Solids IC Engine, Heat, Steam Boiler Waste H2S, H2O Pre-treated Waste Dewatering Digester Effluent Water Treatment Liquid Sludge Can be landfilled or sold (depending on feedstock): Slow nitrogen release fertilizer Animal bedding Animal feed Recycle Biogas Microturbine CO2 removal + NG compression Biogas NG Pipeline CNG for fuel Liquefaction CO2 (sale) LNG for fuel Methane Initial Gas Clean-up Biogas The dilute acid hydrolysis to P-series process description.: The dilute acid hydrolysis to P-series process description. Slurry Mixing Tank Water Treatment Chemicals (further treatment) Two chemicals produced at this phase: Furfural (FF) can be sold directly as a chemical or converted to either Furfuryl Alcohol (for sale to the foundry binders market) or THFA (a solvent that is also a P-series fuel component) Formic Acid can be sold as a chemical or used to produce hydrogen Biomass First-Stage Hydrolysis Intermediate Chemicals Steam Recovery Lignin Cake Acid Recovery Separator Vapor Phases Feed Water Levulinic Acid 1 1 Sulfuric Acid Second-Stage Hydrolysis Levulinic + Formic Acid Flask Separator Recycled Water Crude Levulinic Acid Centrifugal Separator Tars Solvent Extraction Solvent Water Separator Recycled Water Recycled Acid Tar Extraction 3 Lignin / Tar slurry is a low sulfur substitute for #6 fuel oil: It can be used in a boiler to provide the heat requirements for the process It can be sold for its energy content In the case of fuels production, it can be used to produce hydrogen needed for the hydrogenation of levulinic acid The inorganic residue in the boiler or gasification chamber can be disposed of in a landfill or used for concrete aggregate (unless the feedstock contains hazardous inorganic contaminants) 2 Treated Water Levulinic acid can be sold as a chemical or converted to fuels through Esterification to produce Methyl-levulinate (a substitute for #2 heating oil) or Ethyl-levulinate (a diesel fuel additive) Hydrogenation to produce methyltetrahydrofuran (MeTHF), an ether used as a gasoline additive or replacement 3 2 The tipping fee is the main driver of the economics of dilute acid hydrolysis for biofuels production.: The tipping fee is the main driver of the economics of dilute acid hydrolysis for biofuels production. Fuel Production Cost for Dilute Acid Hydrolysis (for Biofuels Production) (2007$) Key assumptions: Debt equity ratio: 40%:60%, Cost of equity = 15%, cost of debt = 8%, Federal income tax rate = 35%; NJ state income tax rate = 9%; Property tax = 1.5%, Insurance = 0.5%, Depreciation under Modified Accelerated Cost Recovery System (MACRS): Depreciation period considered is 15 years. Loan period = 25 years. Project economic life = 25 years. No incentives have been factored into the analysis. Non production-related subsidies (blender’s tax credit, the Renewable Fuels Standards and other blending mandates) are not included as they impact the sales price rather than production costs. The Alternative Fuel Credit of $0.50/gallon, for which P-series fuels are eligible, has not been considered in the analysis as it is likely to be claimed further down the value chain (at the point of blending or sales of the fuel), in a similar to how the Alcohol Fuel Mixture Credit and Biodiesel Mixture Credit are claimed. It is important to recognize that, nevertheless, the fuels produced with this technology will stand to benefit from this tax credit through increased market prices Feedstock costs dominate the economics of biodiesel; the potential impact of technology advancements and scale is noticeable for YG.: Feedstock costs dominate the economics of biodiesel; the potential impact of technology advancements and scale is noticeable for YG. Fuel Production Costs for Biodiesel (2007$) Key assumptions: Debt equity ratio: 40%:60%, cost of equity = 15%, cost of debt = 8%, Federal income tax rate = 35%; NJ state income tax rate = 9%; Property tax = 1.5%, Insurance = 0.5%, Depreciation under Modified Accelerated Cost Recovery System (MACRS): Depreciation period considered is 15 years. Loan period = 25 years. Project economic life = 25 years. Incentives included for 2007 calculation: 10 ¢/gallon small producer tax credit (for 15 MGPY). Non production-related subsidies (blender’s tax credit, the Renewable Fuels Standards and other blending mandates) are not included as they impact the sales price rather than production costs. As a note, soy biodiesel is considered “agri” and therefore granted a higher blender’s tax credit ($1/gallon) than that granted to YG biodiesel ($0.5/gallon) Soy Biodiesel Plant Yellow Grease Biodiesel Plant Ethanol is a clean burning, high octane additive to (or replacement for) petroleum gasoline.: Ethanol is a clean burning, high octane additive to (or replacement for) petroleum gasoline. Corn ethanol is produced by fermenting the starch contained in corn Other established feedstocks for ethanol production are those containing sugars (sugar crops, sorghum, molasses) or where sugars can be easily extracted (barley, wheat, potatoes, rye) ~15% of the 2005 US corn harvest was used for ethanol production Cellulosic ethanol is being developed with the goal of increasing feedstock options Agricultural residues (corn stover, wheat straw), energy crops (switchgrass, miscanthus, woody crops such as poplar), forestry residues, municipal wastes (organic fraction), industry wastes Feedstock Corn ethanol production is a mature technology In a dry mill, the starch fraction is extracted from the grain, grinded, liquefied and hydrolyzed to liberate the sugars for fermentation. The alcohol is then distilled and denatured. Distiller’s Dried Grain (DDG), an animal feed ingredient, is the by-product Wet mills are more capital intensive and designed to optimize the value of co-products Technology improvements will continue to yield better efficiencies and lower costs Cellulosic ethanol production technologies are being developed Technical and economic hurdles still need to be overcome before the technology can be deployed Enzymatic hydrolysis has received attention as the most promising enabling technology Conversion Ethanol in the US is mostly used as an additive to gasoline (up to 10%) for environmental and regulatory compliance, as an octane enhancer or to reduce fuel costs The use of ethanol as a replacement for gasoline (E85) requires modest engine modifications and reduces vehicle range (but not efficiency) due to the 30% lower energy content of ethanol The US and Brazil are the main consumers (and producers) of ethanol; in Brazil, 25% of all motor fuel is ethanol and 80% of new car sales are Flexible Fuel Vehicles (FFV) End-Use The corn and cellulosic ethanol process descriptions.: The corn and cellulosic ethanol process descriptions. Grain Receiving Mash Preparation Fermentation Distillation Centrifu-gation Evapora-tion Dehydr-ation Dryer Denaturant Syrup Wet Grains DDGS 200 Proof Ethanol Fuel Ethanol Process Condensate Beer Corn Mash Corn Meal DDGS 60 Mgpy Corn Ethanol (Dry Mill) Feed Handling Pretreatment & Conditioning Saccharification & Fermentation Distillation, Dehydration, Solids Separation Biomass Cogeneration Denaturant 200 Proof Ethanol Fuel Ethanol Electricity Export (net of facility needs) Beer Steam & Electricity to Process Lignin 10 Mgpy Cellulosic Ethanol (SSF*1) Corn Biomass 1: Simultaneous Saccharification and fermentation Garden State Ethanol, Inc. an EcoComplex Incubator Company: Garden State Ethanol, Inc. an EcoComplex Incubator Company 100 million bushels of corn within 80 mile radius Garden State Ethanol, Inc.: Garden State Ethanol, Inc. Slide15: Thank You!