How Sustainable Can Biodiesel Be? Thatcher Root Department of Chemical & Biological Engineering University of Wisconsin - Madison Liquid fuel from agricultural feedstocks Decreasing process pollution Reducing water needs Use of solid catalyst

Biodiesel Production Conversion of vegetable oil to motor fuel Triglycerides from corn, soy, canola, … Transesterify with alcohol (methanol or ethanol) Catalyze with base or acid TG + 3 ROH  Methyl Esters + Glycerol Focus on heterogeneous base catalyst Simplify separations Eliminate neutralization requirement, water wash Production of clean glycerine phase

Petroleum Consumption in the United States Estimated total petroleum use by sector 4.1 million barrels diesel fuel consumed per day! 2/3 of petroleum consumed goes for transportation! Estimated petroleum product use Diesel fraction is higher in Europe

History of diesel engines Invented in 1893 by Rudolf Diesel Ran on peanut oil at 1900 World’s Fair Switched to cheaper petroleum distillate Fuel must ignite from compression alone Diesel’s first engine

Oil Methyl alcohol (wood alcohol) Biodiesel Glycerin Waste forest products (wood, paper, pulp) Cosmetics Food Pharmaceuticals Inks Heating oil Passenger cars Lye, potash What is biodiesel? ++ Waste fryer oil Vegetable oil

What’s the real deal with biodiesel emissions? Type of emission B100B2 Total unburned hydrocarbons - 67%- 20% Carbon monoxide- 48%- 12% Particulate matter- 47%- 12% Nitrogen oxides+ 10%+2% to -2% Emission reduction measured as compared to 100% petrodiesel.

Biodiesel Chemistry 100 kg10 kg 100 kg 10 kg Equilibrium reaction: Keq = 1 for transesterification Excess methanol used for high conversion Typically 6:1 or 10:1 into reactor Need to recover, recycle excess methanol ~

Production of Biodiesel oil methanol lye + biodiesel glycerin biodiesel water Water wash 3-4 times Glycerin drained, purified, sold Reacts for 3 hours Settles for 24 hours Water drained, discarded Catalyst and alcohol premixed Pump

Potential feedstocks Soybean oil, canola oil Inedible oils –Jatropha Palm oil –Only in tropics Used fryer oil –Needs pretreatment Beef tallow –Edible and inedible Algae –High yield, small scale Canola Soy Jatropha Crop Average oil yield (gallon/acre) Corn18 Soybean48 Sunflower100 Rapeseed (canola) 130 Oil palm640 Algae~10,000

Estimated US production capacity: 580 million gallons Biodiesel Production in the United States

Wisconsin Biodiesel Wisconsin biodiesel production, 2005: 1 million gallons Estimated current production: 2 million gallons Current Wisconsin biodiesel plants: –Renewable Alternatives, Manitowoc –Great Lakes Biofuels, Madison –WE BE Bio, Mauston –WRR Environmental Services, Eau Claire

Future Wisconsin Biodiesel Production Expected Wisconsin production, 2007: 100 million gallons Under construction: –North Prairie Productions, LLC, Evansville 45 million gallons/year –Anamax Energy Services, DeForest December million gallons/year –Two plants proposed for Jefferson and Clinton

Biodiesel Production - Commercial Scale “Home-made” system Use waste fryer fat from restaurants Cook in small batches Waste disposal in city sewers Commercial Scale production - 10 M liter/year Market value of glycerine co-product $1.60/lb /lb /lb recent trend Variation with purity Wash water consumption Methanol, Salt removal Permit issues Soap production Separation Disposal oil methanol lye + biodiesel glycerin biodiesel water Glycerin contains salt, excess methanol Acid to neutralize base Wash water contains soap, salt, methanol Multiple water washes

Biodiesel Reaction Initiation CH 3 OH + NaOH → CH 3 O-Na + H 2 O Methoxide (CH 3 O - ) is active intermediate Form from any basic catalyst or feed Water byproduct leads to soap byproduct Loss of fatty acid chains Difficulty in separation in settling tank Some avoid water by using sodium methoxide Cost, hazard to handle Water levels in alcohol, oil feedstock? Better - avoid free base, and salt, with solid base catalyst Inorganic oxides, salts Ion exchange resins R OCH 3

Biodiesel Product Workup Reactor product has methanol in biodiesel ASTM standard regulates level Affects volatility (vapor pressure) Water wash removes methanol, all polar species Efficiency of wash process affects consumption Huge impact on permit requirements Glycerine byproduct contains excess alcohol, catalyst Use of acid to neutralize Mineral acid (HCl, H 2 SO 4, H 3 PO 4, …) Organic acid (acetic acid, …) Minimal value - as fuel, or feedstock for another process Impact of salt content Ash content prevents use in boilers Affects value for other processes Glycerine price plunging as production rises

Glycerine Byproduct Use Glycerine byproduct from soap - cosmetic use Price plunging as production surges Minimal value - as fuel, or feedstock for another process Impact of salt content Ash content prevents use in boilers Affects value for other processes

Biodiesel Catalyst Goal Ideal catalyst creates methoxide without water formation or salt waste Solid base catalyst: Oxides: MgO + CH 3 OH -> MgOH + + CH 3 O - Ion exchange resins: R OCH 3 Advantages: Catalyst remains in reactor for further use No acid neutralization, new base need Decrease in wash water requirement High quality glycerine byproduct Research on solid base catalysts now underway

Biodiesel Process Improvement Goal Ideal catalyst creates methoxide without water formation or salt waste product Solid base catalyst: MgO + CH 3 OH -> MgOH + + CH 3 O - Catalyst remains in reactor for further use No acid neutralization, new base need High quality glycerine byproduct Research on solid base catalysts now underway

Biodiesel Seasonal Variations Cold Flow Filter Plugging test ASTM standard for flow through wire mesh FAME “wax” crystal formation Variation with fat/oil origin and FAME production Chain length Saturation Alcohol used for ester “Dewaxing” treatment Variation in oil source with seasonal temperature

NExBTL Biodiesel Alternative process from Finland Vegetable oil + hydrogen -> alkanes + water Higher energy content (and input) Propane byproduct Higher capital cost, production cost More conventional petro-diesel-like properties Conventional petro-diesel distribution, processing

Resources National Biodiesel Board: Energy Information Administration: Biodiesel America:

12 Principles of Green Chemistry 1.Prevent waste 2.Design safer chemicals and products 3.Design less hazardous chemical syntheses 4.Use renewable feedstocks 5.Use catalysts, not stoichiometric reagents 6.Avoid chemical derivatives 7.Maximize atom economy 8.Use safer solvents and reaction conditions 9.Increase energy efficiency 10.Design chemicals and products to degrade after use 11.Analyze in real time to prevent pollution 12.Minimize the potential for accidents