Presentation on theme: "Biomass Basics: Renewable Energy and Chemicals Dennis J. Miller Department of Chemical Engineering and Materials Science Michigan State University East."— Presentation transcript:
Biomass Basics: Renewable Energy and Chemicals Dennis J. Miller Department of Chemical Engineering and Materials Science Michigan State University East Lansing, Michigan (517)
Benefits of the Chemical Industry Tell Our Students About It!!
The Emerging Paradigm: Sustainability and Green Chemistry "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” The Brundtland Commission Report, The United Nations, Environmentally Sustainable Economically Sustainable Socially Sustainable
Distribution of proven (oil) reserves 1984,1994, 2004
Oil reserves-to-production (R/P) ratios
Oil consumption by region
Major oil trade movements
Energy Consumption Concepts (A great web site: Material and Energy Balances –How much fossil energy in MJ (oil, coal, gas) does the world use annually? –How much oil does the U.S. use annually? (A: about 1.5 cubic miles) –How many watts per person does that equate to in the U.S.?
Biorenewable Fuels and Chemicals
Corn: The Near-term Biofuels Feedstock 2005 Statistics Production:11.8 billion Bushels Acres planted:80.9 million acres Average yield:160 bushels/acre (vs. 137 bu/a in 2000 !) The corn plant 3.8 tons corn stover / acre (lignocellulosic) 3.8 tons corn grain / acre Societal/Global perspective questions: How much of our fuel needs can corn provide? What are the costs associated with using corn for fuel? How does politics enter into corn ethanol?
Corn to ethanol energetics C 6 H 12 O 6 = 2 C 2 H 5 OH + 2 CO 2 glucose ethanol carbon dioxide 1.0 kg 0.51 kg 0.49 kg 17 MJ 15.8 MJ0 MJ Theoretical yield 2.7 gal/bu EtOH yield (grain only): 450 gal/acre EtOH yield w/ 50% stover: 670 gal/acre Ethanol energy content 80,000 Btu/gal Gasoline energy content 130,000 Btu/gal
Ethanol fuel supply U.S. gasoline consumption (2006): 150 billion gal U.S. fuel ethanol consumption (2006): 6 billion gal –4% of total gasoline demand –Blended 10% with gasoline (40% of U.S. gasoline contains ethanol) –14 million of 80 million acres of corn harvested Ethanol energy exercises How much corn would be required to provide E10 for the entire U.S.? A: About ~5 billion bushels (40% of 2006 U.S. crop) What land mass would be required to replace all U.S. gasoline with ethanol? A: 200 billion gal EtOH equates to 75 billion bushels corn / yr or 300+ million acres (22% of U.S. landmass)!
Cellulosic Biomass – long-term renewable biofuel feedstock Composition (wt%)WoodSwitchgrass Cellulose Hemicellulose Lignin Yield(ton/acre) Ethanol yield (gal/ton) Challenges –Switchgrass is low-density compared to corn, more costly to collect and transport. –Cellulose difficult to hydrolyze (structural polymer); starch is amorphous and easy to hydrolyze. –Can burn lignin to provide energy for plant operation
Senior Design Problem: Bioenergy plantation design Fundamental concept: there exists an optimum biorefinery capacity (M) for biofuel production. (Tradeoff between capital cost (~M 0.6 ) and cost of transporting biomass (~M 1.5 )). Process energy provided by lignin combustion Can choose parameters arbitrarily or use standard values (NREL website). Possibilities for open-ended design, multiple smaller “feeder” process units in remote locations.
Biomass Plantation Economics (NREL)
Biodiesel from plant oils Plant oils include soy, rapeseed, canola, etc.. Waste cooking oils are minor potential source, are inexpensive, but contain water and free fatty acids that must be cleaned up. Other sources include algae, sewage, etc.. Reversible reaction system Typical methanol:oil feed ratio of 6:1 gives two product phases, >98% methyl ester yield
Current biodiesel production (Batch production, labor and energy intensive) Plant oil (100 kg) (30 gal) Methanol (22 kg) (6:1 ratio) NaOCH 3 (0.5 kg) 60 o C, 2 hr purification Glycerol + NaOCH 3 Biodiesel Product (100 kg) (30 gal) Neutralize purify Glycerol byproduct (10.4 kg) (0.7 lb/gallon)
Biodiesel in the classroom Material and energy balances : a) Calculate stoichiometric reaction masses, byproduct glycerine yields b) Calculate biodiesel energy density relative to diesel fuel c) Optimizing energy yields from land - Which fuel type gives higher energy yield per acre, biodiesel or ethanol? Canola: 1000 kg/acre*0.44 kg oil/kg canola*39 mJ/kg = MJ/acre Ethanol: 160 bu/acre*2.7 gal/bu*3 kg/bu*27 MJ/kg = MJ/acre Reaction engineering: Make biodiesel as classroom demo (cooking oil + methanol + sodium hydroxide/methoxide) Good example of homogeneous catalysis (can see color change upon addition of sodium hydroxide in methanol)
Chemical Building Blocks from Biomass Carbon number Biomass Blocks Petroleum Blocks C 1 methanol, COmethane C 2 acetic acid, ethanolethylene C 3 lactic acid, acetone, propylene propionic acid, glycerol C 4 succinic acid, n-butanolisobutylene 3-hydroxybutyratebutadiene C 5 xylose, glutamic acid 3-hydroxyvalerate C 6 glucose, lysinebenzene C 7, C 8 toluene xylene
Lactic Acid Fermentation: C 6 H 12 O 6 2 C 3 H 6 O 3 (glucose) (lactic acid) - Yields exceed 0.95 lb/lb glucose - Product concentrations > 90 g/L - Production rates > 3 g / L· hr - Ca(OH) 2 to neutralize, acidulation w/ H 2 SO 4 (CaSO 4 waste) Production cost: < $0.25 / lb Production capacity: 350 MM lb/yr (Cargill) 100 MM lb/yr (all others)
Equilibrium Lactate Ester Reactions Nominal lactic acid concentration (wt%) L1L1 L2L2 L3L3 L4L Equilibrium oligomer distribution - Lactic acid oligomerization reactions characterized by K e = 0.23
Lactate esters via reactive distillation Lactic Acid + Ethanol = Ethyl lactate + Water Lactic Acid Ethanol Water Ethyl Lactate Ethanol + Water Ethyl Lactate (+ oligomers)
Wt % EtOH EtLA 0.13 Water Stream 3 Flow kmol/hr Wt % LA 0.00 EtOH 0.30 EtLA Water 0.13 L2ES L3ES 6.11 L2 Acid 0.66 L3Acid 0.63 Stream 4 Flow 9.90 kmol/hr Wt % EtOH Feed Stream 2 Flow 54.0 kmol/hr 85C 1.16 atm Wt % LA 58.0 Water 14.0 L2 Acid 22.0 L3 Acid 8.0 Feed Stream 1 Flow kmol/hr 25C Reactive distillation for lactate ester production 7 FEED (88% LA feed) LA : kmol/hr L2 Acid : kmol/hr L3 Acid : kmol/hr Water : kmol/hr EtOH : kmol/hr # Stages35 Reflux ratio0.1 Lactic acid conversion (%) >99
Chemicals from Renewables Material balances/reaction engineering: Determine theoretical yields - renewables generally undergo weight loss in conversion, whereas petroleum generally undergoes weight gain in conversion. Separations: schemes for purifying low volatility organic/renewable products (evaporation, reactive distillation, chromatography, other novel separations) Thermodynamics: Many biobased reactions are reversible, involve nonideal solutions, physical properties estimation required
Summary Renewable fuels and chemicals can be incorporated across the core ChE curriculum –Energy and mass balance calculations –Thermodynamics: physical properties, phase equilibria, reaction equilibria –Reaction engineering: kinetics, reactor design, catalysis –Separations: design separations schemes for non- volatile, thermally fragile compounds –Process design: core chemical engineering principles and unit operations are key to designing biorefineries
GREEN CHEMISTRY DEFINITION Green Chemistry is the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products *. GREEN CHEMISTRY IS ABOUT (12 principles) Waste Minimisation at Source Use of Catalysts in place of Reagents Using Non-Toxic Reagents Use of Renewable Resources Improved Atom Efficiency Use of Solvent Free or Recyclable Environmentally Benign Solvent systems
Traditional Synthesis of Ibuprofen (CH 3 CO) 2 O AlCl 3 O I¯Bu ClCH 2 CO 2 C 2 H 5 NaOC 2 H 5 O CHCO 2 C 2 H 5 I¯Bu H+ H20H20 CHO I¯Bu H 2 NOH I ¯ Bu C N CH NOH I¯Bu CO 2 H Ibuprofen (BASF and Celanese Corporation) 60% Waste
Green Chemistry Alternative Synthesis of Ibuprofen PGCC Winner 1997 (CH 3 CO) 2 O HF catalyst H2H2 CO, Pd CO 2 H O OH Ibuprofen (BASF and Celanese Corporation) 1% Waste + CH 3 COOH
Green chemistry in the curriculum Material and Energy Balances –Define and implement atom economy and waste generation into stoichiometry problems –Yield calculations for multiple step syntheses Reaction Engineering and Design courses –Carry out reactor design for green process and compare with traditional process Resource: ACS Green Chemistry Institute