How Green can Biodiesel Be? Ruminations by Thatcher Root Department of Chemical & Biological Engineering University of Wisconsin - Madison

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

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

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

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

Production of biodiesel oil methanol lye + biodiesel glycerin biodiesel water Water wash 3-4 times Glycerin drained, purified, sold Reacts for 3 hours at 140°F Settles for 24 hours Water drained, discarded Catalyst and alcohol premixed Pump

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.

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 –10,000 gal/acre Canola Soybean Jatropha

Comparison of annual oil yields CropAverage oil yield (gal/acre) CropAverage oil yield (gal/acre) Corn18Rapeseed (canola) 127 Soybean48Oil palm635 Sunflower102Algae10,000

BQ-9000 is a voluntary accreditation program through the National Biodiesel Board Estimated US production capacity: million gallons Biodiesel Production in the United States

Current Wisconsin Biodiesel Production 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

Production of biodiesel oil methanol lye + biodiesel glycerin biodiesel water Water wash 3-4 times Glycerin drained, purified, sold Reacts for 3 hours at 140°F Settles for 24 hours Water drained, discarded Catalyst and alcohol premixed Pump

Biodiesel Production - Scale “Home Brew” system Use waste fryer fat from restaurants Cook in small batches Waste disposal in city sewers Commercial Scale production - 5 M gal/year Market value of glycerine co-product $1.60/lb /lb /lb Variation with purity Wash water consumption - permit issues Soap production Separation Disposal

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

Biodiesel Chemistry 100 lbs10 lbs100 lbs10 lbs

Biodiesel Reaction Initiation CH 3 OH + NaOH → CH 3 O-Na + H 2 O Methoxide 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 Avoid water by using sodium methoxide at start Cost, hazard to handle Water levels in alcohol, oil feedstock?

Biodiesel Product Workup Reactor product has methanol in biodiesel ASTM standard regulates level Affects volatility (vapor pressure) 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, …) Water wash removes methanol, all polar species Efficiency of wash process affects consumption Huge impact on permit requirements

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 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

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