1Bio-fuels and hybridsProf. Wai ChengSloan Automotive Lab, MIT2The backdrop3Transportation and Mobility• Transportation/mobility is a vital to modern economy–Transport of People–Transport of goods and produce• People get accustomed to the ability to travel4Transportation needs special kind of energy source• Vehicles need to carry source of energy on board• Hydrocarbons are unparalleled in terms of energy density– For example, look at refueling of gasoline• ~40 Liters in 2 minutes (~0.25 Kg/sec)– Corresponding energy flow= 0.25 Kg/sec x 44 MJ/Kg= 11 Mega WattsLiquid hydrocarbons !5What is in a barrel of oil ?(42 gallon oil → ~46 gallon products)Source: California Energy Commission, Fuels OfficeAsphalt and Road OilLiquefied Refinery GasResidual Fuel OilMarketable CokeStill GasJet FuelDistillate Fuel OilFinished Motor GasolineLubricantsOther Refined Products0.90%1.50%1.90%2.80%3.30%5.00%5.40%12.60%15.30%51.40%Typical US output6US Use of Petroleum by sector1970 1980 1990 2000 20100510152025Millions of Barrels/dayYearTransportationIndustrialResidentialCommercialElectric utilitiesSource: US Dept. of Energy7Oil Supply (annual average up to 2007)Source: EIA01020304050607080901001960 1970 1980 1990 2000 2010YearMillion Barrels/dayUSOPECOthersHubbert peak8The world Hubbert peakSource: http://www.fossil.energy.gov/programs/reserves/npr/publications/npr_strategic_significancev1.pdf(excluding OPEC & Russian production)20039Petroleum price0.0020.0040.0060.0080.00100.00120.001860 1880 1900 1920 1940 1960 1980 2000Yom Kippur WarArab Oil EmbargoIranian RevolutionIran/Iraq WarConstant 2004$$ of the dayOil from North Sea, AlaskaGulf WarDecrease in demand, increase in non-OPEC supplySaudi increase production2008 av. value up to June;6/6/08 @$118/Barrel$/BarrelSources: Data from EIA; event labels from WTRG Economics9/11Demand of emerging market; limited refinery capacityIraq war10CO2emissions from fossil fuel1750 1800 1850 1900 1950 20000100020003000400050006000700080001750 1800 1850 1900 1950 2000110102103104YearYearMillion metric tons of Carbon/yearTotalLiquid fuelTotalLiquid fuelSource: EIA11The drive to bio-fuel• Increasing demand of liquid fuel for transportation– Population– Society affluence• Drive for lower CO2 production• Perceived decline of petroleum reserve• Fuel price• Government Policy– Tax credit– Required bio-fuel content12What is bio-fuel?13Dominant biofuelsSugar based(corn, sugarcane, …)Cellulosic based(switchgrass, wood, …)EthanolUsageE10, E20, E85, …Crop based(rapeseed, soybean, …)Wasted oil/ animal fatAlgaeBio-dieselB10, B20, ….Compatible with current engine technology and fuel infra structure(BTL fuel not included in this discussion)14Example: Ethanol production from cornCornStarchSugarEthanol + CO2Ethanol fuelBy-productsFermentationPurification(removal of water, …)Resources:EnergyMaterialsLabor15Example: bio-diesel productionSoy,rapeseed, …Oil (tri-glyceride)Transesterification using alcohol (methanol) with alkaline catalystMechanical or solvent (hexane) extraction + water removalEsters and glycerolBio-diesel (esters)Purification(removal of glycerol, alkaline, fatty acid, …)CH2-OOC-R1CH2-OOC-R3CH-OOC-R2+3ROH ↔||R-OOC-R1R-OOC-R3R-OOC-R2Tri-glyceride Esters+(CH2OH)2-CHOHGlycerolResources:EnergyMaterialsLabor(typically 8-22 C to 2 O)AlkalineCatalyst(KOH)16Combustion characteristics of bio-fuelBio-ester data from Graboski and McCormick, Prog. Energy Comb. Sc., Vol. 24, 1998Cetane numbers.g. LHV (MJ/kg)LHV (MJ/L)B10 LHV (MJ/L)B20 LHV (MJ/L)LHV B10/ Diesel (by vol.)LHV B20/ Diesel (by vol.)Diesel45-55 0.820 43.22 35.44Soybean oil methylester 50.9 0.885 37.01 32.76 35.17 34.91 0.992 0.985Rapeseed oil methylester 52.9 0.882 37.30 32.90 35.19 34.93 0.993 0.986Sunflower oil methylester 49 0.880 38.53 33.91 35.29 35.14 0.996 0.991Frying oil ethylester 61 0.872 37.19 32.41 35.14 34.84 0.991 0.983Octane numbers.g. LHV (MJ/kg)LHV (MJ/L)E10 LHV (MJ/L)E85 LHV (MJ/L)LHV E10/ Gasoline (by vol.)LHV E85/ Gasoline (by vol.)Gasoline95 0.780 44.00 34.32Ethanol107 0.785 26.90 21.12 33.00 23.10 0.962 0.67317Stoichiometric requirement for different fuels1 1.5 2 2.5 3 3.5 424681012141618Fuel H to C ratio(A/F)stoiciometricGasoline and dieselGasoline with 11% MTBEEthanolMethanolO/C = 0O/C = 0.5O/C = 1Gasoline with 10% EthanolE85O/C ratios of bio-diesel esters ~ 0.12B10018Relative CO2 production from burning different fuel moleculesC. Amann, SAE Paper 909209919Effects of Oxygenates on PM emissionAVL Publication (by Wofgang Cartellieri in JSME 1998 Conference in Toykyo)20Bio-fuel combustion properties• Bio-diesels and ethanol are fundamentally clean and attractive fuels to be used in engines• The use of these fuels as supplements to petroleum base fuel are compatible with current engine configuration and fuel infra-structure• Practical issues can be adequately handled by engineering– Fuel quality– Engine calibration– Materials compatibility, viscosity, …Burning the fuel is the least of the problem !!!21Status of bio-fuel production22World liquid fuel production (2005)Source: http://www.wilsoncenter.org/topics/pubs/Brazil_SR_e3.pdfMT = Million tonsBGJ = Billions of giga (1018)JoulesHYDROCARBONSRENEWABLES23Liquid fuel supply projectionSource: ExxonMobil – JSAE meeting, Kyoto, July 23-26, 20071980 1990 2000 2010 2020 2030120100806040200Millions of barrels per day oil equivalent24US bio-fuel capacityYield dependent on location and weatherCrop based bio-fuels do not have enough capacity to meet the liquid fuel demand !!!US biofuelsUS harvested crop land (US agriculture census 2002), hectareUS all distillate use (diesel+jet+power gen etc.) EIA2007; L/yrUS gasoline use, EIA 2007; L/yr1.23E+083.34E+115.40E+11gal/acre L/hectareLimit of production (gal)Limit of production (L)Energy ratio of limit to demandbio-dieselpalm oil 5.08E+02 4,7561.54E+11 5.85E+111.63coconut 2.30E+02 2,1536.99E+10 2.65E+110.74rapeseed 1.02E+02 9553.10E+10 1.17E+110.33soy 6.00E+01 5621.82E+10 6.91E+100.19peanut 9.00E+01 8432.73E+10 1.04E+110.29sunflower 8.20E+01 7682.49E+10 9.44E+100.27jatropia (SE Asia) 2.00E+02 1,8726.08E+10 2.30E+110.64algae (?) 1.80E+03 16,8505.47E+11 2.07E+125.78ethanolcorn 3.44E+02 3,2171.04E+11 3.96E+110.71sugar cane (Brazil) 8.00E+02 7,4892.43E+11 9.21E+111.7125Algae: micro-seaweedsIssues• Production – Need high lipid content species– Need fast growth species–Growth in dense environment• Harvest techniques• Oil extractionCourtesy of