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C6370 Peter Lund 2015
Lecture 11_a
Biofuels
• Liquidbiofuelsfrombiomass
• Bioethanol,biomethanol,other
• Feedstocks,productionprocesses
• Energybalances,potentials
Biofuel use today
C6370 Peter Lund 2015
• USA&Brasilia96%ofbioethanol,Germany60%ofbiodiesel
• EU:10%ofallfuelsin2010needtobebiobased
C6370 Peter Lund 2015
Issue of conflicts with food production in the future?
Food and fibres
biofuel
Examples of biofuel chains
C6370 Peter Lund 2015
Processes Products Biomass source
Sugar+starch Sugarcane, sugarbeats, maize, corrn
Fatty acids (oils) Rape, palm, jatropha
Cellulose Grass, bagasse, straw, wood
Source: UPM/Sohlström
C6370 Peter Lund 2015
Basics of biofuels (liq)
• ChemicalformsofbiomassCO2+sun+water→sugar
starch(e.g.corn) Cellulose+hemicellulose (differentpolymericformsof carbohydrates)
+lignin=wood• Liquidformsofbioenergy
– Ethanol(fermentationandmethanol(thermalprocess)– ETBEandMTBE)(additivesingasoline) – Gasohol(85%ethanolormethanol+15%gasoline),M85jaE85– Rapeseeds(biodiesel),NeXT-biodiesel(NesteOil)– BTL,Fischer-Tropschprocesses
C6370 Peter Lund 2015
Biomass composition
• CarbohydratesCm(H2O)nclassi[iedaccordingtotheamountofsugarmolecules:mono,di,tri,polysaccharides;5Catoms=pentose,6Catoms=hexoses
• Sugars– Canesugar(=sucrose)àglucose+fructose(six-carbonsugars)throughhydrolysis
• Starch– Polysaccharid;hydrolysisofstarch(acidoramylase)yieldsglucose– 70%ofcornisstarchamixofstraight-chainedandbranchedpolymersofglucose,molecularweightsupto1-2million)
• Cellulosicbasedbiomass– Carbohydratepolymers:cellulose,hemicellulose,;lignin– Celluloseiscomposedoflongchainsofglucosemoleculeswithacrystallinestructure
– Hemicellulosecontainsdifferentsugars,nocrystallinestructure(inhardwoodxylose)
C6370 Peter Lund 2015
Production of ethanol
• Producedthroughfermentation• Biomass+biocatalystsàethanol
– Starch+enzyme(amylase)oracid→glucose(sugar)– Cellulose+enzyme(cellulase)oracid→glucose– Hemocelluose+xylose→differentkindofsugarse.g.xylose→
• Lowyieldsofethanol– Glucose(fermentation,bacteria)→ethanol– Theaboveprocessedworkinnaturalconditions,enzymescatalyzejustonereactionatime
C6370 Peter Lund 2015
Process steps for ethanol from lignocellulosic biomass (2 gen biofuels)
• Pretreatmentofbiomassfeedstock• Hydrolysis(sugar)• Ethanolfermentation(ligninaswaste)• Biomasspretreatedtobeenzymesensitive(e.g.
weekacid,0.5%sulphuracid)→hemicellulosehydrolysesintoxylose→celluloseandligninremains
• Basicreactioninvolved– Hemicellulose:(C5H8O4)n+nH2O→nC5H10O5– Cellulose:(C6H10O5)n+nH2O→nC6H12O6– (C6H12O6)n+nH2O→2C2H5OH+2CO
• 100kgfeedstock→50-60kgethanol;½turnsintoCO2,but96%oftheheatingvalueofcelluloseremains
• 1000kgstarch/cornà440lethanol• Theprocessyields3-12%alcohol,restiswater
whichneedtoberemove(needsenergy)
yeast
cellulase acid
C6370 Peter Lund 2015
Production of biomethanol
• Methanolisanimportantindustrialchemical(ca30billionl/year)
• Two-stepprocess– 1)syngasproduction,2)catalyticconversionintomethanol
– Biomassgasi[icationàsteamreformationàShiftreactionàMethanolsynthesis
• Chemicalreactions:– Biomass+H2O→CO+H2(syngas)– CO+H2O→CO2+H2(shiftconversion)– 2H2+CO→CH3OH+heat(methanol)– 3H2+CO2→CH3OH+H2O
C6370 Peter Lund 2015
Biodiesel from oilseeds(1 gen) • RME=rapemethylester;n0.6-1ton/ha• Separation:rape(3000kg)→rapeoil(1000kg)+proteincake(1900kg)• Esteri[ication:rapeoil+methanol→glyserine(110kg)+RME(1000kg)• Tropicalplants:jatropha1,6-3,2ton/ha;palmoil4-6ton/ha
Summary of energy ratios of biofuels from different sources
• Cellulosicethanol 2-36• Palmoil 9• Sugarcaneethanol 8• Wastebiodiesel 6• Soyadiesel 2-3• Cornethanol 2(USA)• Cornethanol 1.2• Diesel 0.8-0.9• Gasoline 0.8• Oilshale 0.75
• Energyratio=energyoutput/energyinputs
C6370 Peter Lund 2015
Production price trends for biofuels
• Sugarcanebioethnanol0.2-0.25€/l(gasolineequivalent)• Cellulosicethanol0.25-0.55• Cornethanol(USA)0.3-0.45• Cornethanol(EU)0.35-055• Wastebiodiesel0.2-0.3• Soyadiesel0.30.55• Rapeiesel0.3-0.55• FTbiodiesel0.35-0.6
C6370 Peter Lund 2015
Your Work # 11 • HomeworkfromLecture11
– Howseverearetheissuesrelatedtobiofuelproduction?Biodiversity,con[lictswithfoodproduction,humanrights,etc.
– Wewillspendtogether5minutesonthisquestion
• InpreparingforLecture12(fuelcellsandH2)– Havealookonfc&h2stuff,justoverview)
C6370 Peter Lund 2015
Conversion of biomass into biofuels
• Thermal,chemicalandbiochemicalprocessesforconvertingorganicmaterialintobiofuels
C6370 Peter Lund 2015
C6370 Peter Lund 2015
EU:s own feedstock sources for biofuel production
• Biofuel production could meet 10-20% of EU’s fuel need,
• Example of land-area needed to produce 6% of EU fuel needs
Lähde: EEA
C6370 Peter Lund 2015
Nya biobränslen (ersättning av olja)
• Tra[ikensbränslebehov4.000.000ton/år• EU-direktivet:biobränslenminst230.000ton/år2010;Inhemsk
produktion100.000-200.000ton/årmöjligtenligtodlingsarealen(biodieselochetanol)
• Framtidaenergiodlingar– Rapsochrybs0,6ton/ha(biodiesel);[inskproduktionmotsvararca45.000tonRME/år;max.300.000ton(100%avdjurfodersombiprodukt)
– Bioetanolfrånsockerbetor(1000milj.kg)~150.000ton;35ton/ha;ca0.4€/litermeddagensintäktsnivå
– Rör[len30MWh/ha(metan40.000km/haellerfastbränsle);t.ex.500.000ha=1.500.000tonbiogas
• Biogas(metan)– Samhällsavfall;livsmedelindustrin0,6;avfallsvatten0,9;jordbruksavfall30-140;energiodlingar7;sopgas0,7TWh/år