HYDROCARBON BIOREFINERY
ofBiomassforHydrocarbon Biofuels
EditedBy
SUNILK.MAITY
DepartmentofChemicalEngineering,IndianInstituteofTechnology Hyderabad,Sangareddy,Telangana,India
KALYANGAYEN
DepartmentofChemicalEngineering,NationalInstituteofTechnology Agartala,Agartala,Tripura,India
TRIDIBKUMARBHOWMICK
DepartmentofBioengineering,NationalInstituteofTechnology Agartala,Agartala,Tripura,India
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Contributors
R.S.Ajmal
DepartmentofChemicalEngineering,NationalInstituteofTechnologyCalicut,Kozhikode, India
WaqasAslam
AustralianInstituteforBioengineeringandNanotechnology(AIBN),TheUniversityof Queensland,Brisbane,QLD,Australia
NeerajAtray
BiofuelsDivision,CSIR-IIP,Dehradun,India
NunoBatalha
SchoolofChemicalEngineering,FacultyofEngineering,ArchitectureandInformation Technology,TheUniversityofQueensland,Brisbane,QLD,Australia
ThalladaBhaskar
MaterialResourceEfficiencyDivision,CSIR-IndianInstituteofPetroleum,Dehradun, Uttarakhand;AcademyofScientificandInnovativeResearch(AcSIR),Ghaziabad,India
AmanKumarBhonsle
AcademyofScientificandInnovativeResearch(AcSIR),Ghaziabad;BiofuelsDivision, CSIR-IIP,Dehradun,India
TridibKumarBhowmick
DepartmentofBioengineering,NationalInstituteofTechnologyAgartala,Agartala,Tripura, India
BhabatushBiswas
DepartmentofBioengineering,NationalInstituteofTechnologyAgartala,Agartala,Tripura, India
PareshButolia
SchoolofChemicalEngineering,SungkyunkwanUniversity,Seoul,SouthKorea
JyotiPrasadChakraborty
DepartmentofChemicalEngineeringandTechnology,IndianInstituteofTechnology(Banaras HinduUniversity),Varanasi,UttarPradesh,India
SudiptaDe
KAUSTCatalysisCenter(KCC),KingAbdullahUniversityofScienceandTechnology, Thuwal,SaudiArabia
GabrielFraga
SchoolofChemicalEngineering,FacultyofEngineering,ArchitectureandInformation Technology,TheUniversityofQueensland,Brisbane,QLD,Australia
KalyanGayen
DepartmentofChemicalEngineering,NationalInstituteofTechnologyAgartala,Agartala, Tripura,India
JoshuaGorimbo
ZhijiangCollege,ZhejiangUniversityofTechnology,Shaoxing,Zhejiang,China
ShelakaGupta
MultiscaleModellingforEnergyandCatalysisLaboratory,DepartmentofChemicalEngineering, IndianInstituteofTechnologyHyderabad,Kandi,Telangana,India
M.AliHaider
RenewableEnergyandChemicalsLaboratory,DepartmentofChemicalEngineering,Indian InstituteofTechnologyDelhi,HauzKhas,Delhi,India
OlusolaO.James
ChemistryUnit,FacultyofPure&AppliedSciences,KwaraStateUniversity,Malete,Kwara State,Nigeria
JanakiKomandur
DepartmentofChemicalEngineering,IndianInstituteofTechnologyGuwahati,Guwahati, India
MuxinaKonarova
AustralianInstituteforBioengineeringandNanotechnology(AIBN),TheUniversityof Queensland,Brisbane,QLD,Australia
AdarshKumar
MaterialResourceEfficiencyDivision,CSIR-IndianInstituteofPetroleum,Dehradun, Uttarakhand;AcademyofScientificandInnovativeResearch(AcSIR),Ghaziabad,India
PankajKumar
DepartmentofChemicalEngineering,BirlaInstituteofTechnologyandScience(BITS),Pilani, HyderabadCampus,Hyderabad,Telangana,India
AlekhyaKunamalla
DepartmentofChemicalEngineering,IndianInstituteofTechnologyHyderabad,Kandi, Sangareddy,Telangana,India
XinyingLiu
InstitutefortheDevelopmentofEnergyforAfricanSustainability(IDEAS),Universityof SouthAfrica(UNISA),FloridaCampus,Johannesburg,SouthAfrica
SwarnalathaMailaram
DepartmentofChemicalEngineering,IndianInstituteofTechnologyHyderabad,Kandi, Sangareddy,Telangana,India
SudipMaity
Gasification,CatalysisandCTLResearchGroup,CentralInstituteofMiningandFuelsResearch (DigwadihCampus),Dhanbad,Jharkhand,India
SunilK.Maity
DepartmentofChemicalEngineering,IndianInstituteofTechnologyHyderabad,Kandi, Sangareddy,Telangana,India
KaustubhaMohanty
DepartmentofChemicalEngineering,IndianInstituteofTechnologyGuwahati,Guwahati, India
MahluliMoyo
InstitutefortheDevelopmentofEnergyforAfricanSustainability(IDEAS),Universityof SouthAfrica(UNISA),FloridaCampus,Johannesburg,SouthAfrica
MuthusivaramapandianMuthuraj
DepartmentofBioengineering,NationalInstituteofTechnologyAgartala,Agartala,Tripura, India
GregPerkins
SchoolofChemicalEngineering,FacultyofEngineering,ArchitectureandInformation Technology,TheUniversityofQueensland,Brisbane,QLD,Australia
PanneerselvamRanganathan
DepartmentofChemicalEngineering,NationalInstituteofTechnologyCalicut,Kozhikode, India
JanakanS.Saral
DepartmentofChemicalEngineering,NationalInstituteofTechnologyCalicut,Kozhikode, India
TahirHussainSeehar
DepartmentofEnergyTechnology,AalborgUniversity,Aalborg,Denmark;Departmentof Energy&EnvironmentEngineering,DawoodUniversityofEngineering&Technology, Karachi,Sindh,Pakistan
AyazAliShah
DepartmentofEnergyTechnology,AalborgUniversity,Aalborg,Denmark;Departmentof Energy&EnvironmentEngineering,DawoodUniversityofEngineering&Technology, Karachi,Sindh,Pakistan
KamaldeepSharma
DepartmentofEnergyTechnology,AalborgUniversity,Aalborg,Denmark
BhushanS.Shrirame
DepartmentofChemicalEngineering,IndianInstituteofTechnologyHyderabad,Kandi, Sangareddy,Telangana,India
MalayilGopalanSibi
SchoolofChemicalEngineering,SungkyunkwanUniversity,Seoul,SouthKorea
JasvinderSingh
MaterialResourceandEfficiencyDivision,CSIR-IndianInstituteofPetroleum(CSIR-IIP), Dehradun;AcademyofScientificandInnovativeResearch(AcSIR),Ghaziabad,India
SatyanshSingh
DepartmentofChemicalEngineeringandTechnology,IndianInstituteofTechnology(Banaras HinduUniversity),Varanasi,UttarPradesh,India
SaqibSohailToor
DepartmentofEnergyTechnology,AalborgUniversity,Aalborg,Denmark
DeepakVerma
SchoolofChemicalEngineering,SungkyunkwanUniversity,Seoul,SouthKorea
Hydrocarbonbiorefinery: Asustainableapproach
AlekhyaKunamallaa,SwarnalathaMailarama,BhushanS.Shriramea, PankajKumarb,andSunilK.Maitya
aDepartmentofChemicalEngineering,IndianInstituteofTechnologyHyderabad,Kandi,Sangareddy,Telangana,India bDepartmentofChemicalEngineering,BirlaInstituteofTechnologyandScience(BITS),Pilani,HyderabadCampus, Hyderabad,Telangana,India
1.7.2
Abbreviation
2,5-DMF 2,5-dimethylfuran
2,5-DMTHF 2,5-dimethyltetrahydrofuran
2-MF 2-methylfuran
2-MTHF 2-methyltetrahydrofuran
5-EMF 5-ethoxymethylfurfural
ABE acetone–butanol–ethanol
FTS Fischer-Tropschsynthesis
GVL γ-valerolactone
HAA hydroxyalkylation-alkylation
HDO hydrodeoxygenation
HMF 5-hydroxymethylfurfural
LA levulinicacid
MMT millionmetrictons
MON motoroctanenumber
RON researchoctanenumber
1.1Introduction
Transportationfuelsplayanextremelyvitalroleinpresentsociety.Gasoline,diesel,and jetfuelaremajorliquidtransportationfuelsatthemoment.DieselistheprimarytransportationfuelinIndiathataccountsformorethan75%oftransportationfuelsconsumed inthecountry.Ontheotherhand,gasolineisthemajortransportationfuelintheUnited States.Thesetransportationfuelsarethemajorenergy-consumingsector,accountingfor about28%oftheworld’senergyconsumption [1].Theyaremainlyproducedfromcrude oil.However,somecountriesintheworldblendalimitedamountofbiomass-derived fuelswiththesetransportationfuels.Petroleumis,however,limitedandnonrenewable. Thecurrentconsumptionrateindicatesthatexistingpetroleumreserveswillbe exhaustedwithinthenext50years [1].However,reservoirssometimesproducemore petroleumthantheestimatedreserveduetotheapplicationofenhancedrecoverytechniques.Moreover,newpetroleumreservoirsarediscoveredfromtimetotime.Therefore,petroleummaylastalittlelongerthan50years.Moreover,thesetransportationfuels areresponsibleforemissionsofcarbondioxide,NOx,unburnedhydrocarbons,andparticulatematterintotheatmosphere.Theseemissionsareaccountableforglobalwarming andunhealthyairquality,causingvarioushealthissues.Petroleumreservesarealsolimitedinmanycountriesintheworld.Forexample,Indiaimportsabout84%ofthepetroleumconsumedinthecountry.Therefore,theproductionoftransportationfuelsfrom
renewablesourcesisessentialforthesustainabilityofhumancivilizationandmaintenance ofcleanairquality.
Biomassistheonlycarbon-basedrenewableenergysourcewiththepotentialtoprovidetransportationfuels,calledbiofuels.Itmaybeemphasizedthatpetroleumhasbeen originatedfrombiomass.Thebiofuelsarecarbon-neutral.Thecarbondioxideemitted fromthesebiofuelsisreusedforthegrowthofbiomass,therebypreventingglobalwarmingandmaintainingconsistentairquality.Thebiofuelsfurtherofferadvantages,suchas theutilizationofwastebiomassandimprovementintheruraleconomy.Thebiomasscan alsoproviderenewableorganicchemicals,heatenergy,andelectricity.Incontrast,other renewableenergies,suchassolar,wind,hydrothermal,etc.,provideonlyenergyinthe formofelectricityandheat.Biomassisthusconsideredthemostpromisingrenewable energysource.Inancienttimes,humancivilizationwasdependentonbiomassforits energyneeds.Untilnow,biomassremainstheprimaryenergysource,mostlyforcooking,inseveralunderdevelopedordevelopingcountries.Currently,biomassdelivers around10%oftheworld’senergyor50%ofrenewableenergy.Biomassandwaste accountforabout22%ofenergyconsumptioninIndia [2].TheEuropeanRenewable EnergyCounciltargeted50%contributionofrenewableenergyintheworld’senergy consumptionby2040.Anticipatingthepotentialsofbiomass,theInternationalRenewableEnergyAgencyproposedsubstitutingabout22%oftransportationfuelswithbiofuels by2050 [3].Thischapterthusprovidesanoverviewofthevariousbiomasssourceswith theiravailabilityandchemicalstructureanddifferenttypesofbiorefineryfortheproductionofnumerousbiofuels.Thischapter,specifically,introducesanovelhydrocarbon biorefineryconceptformanufacturinghydrocarbonbiofuelsandbuilding-blockchemicalsfrombiomassandtheroleofheterogeneouscatalysisinthisbiorefinery.
1.2Biomass
Thedefinitionofbiomasshasbeenwidenedsincetheevolutionofbioenergyconcepts. Biomassisarenewableorganicmatterthatbroadlyincludesplants,microorganisms,and animalwastes.Basedontheirsource,biomassisclassifiedasenergycrops,wastes,and residuesobtainedfromagriculturecropsandforestmanagement,wastesgeneratedfrom industriesandmunicipality,andaquaticplants(Table1.1) [4,5].
1.2.1Typesofbiomass
Energycrops.Energycropsarecultivatedwittinglyforbioenergyproduction.These energyplantationsarelow-cost,short-rotation,andhigh-yieldingvarietiesthatneed nominalmaintenance.Thesededicatedcropsencompasswood,perennialforage,sugar, starch,andoil-basedenergycrops.Thewoodyenergycropshaveawidegeographical distributionwithhighpotentialyields.Theyarecultivatedonarotationalbasisforpulp production.Theperennialforageenergycropsareadaptableinthewastelandandrequire
Table1.1 Differenttypesofbiomassbasedontheirsource.
Energycrops
Oilcrops Oilseedrape,sunflower,castoroil,olive,coconut,groundnut, jatropha,soybeanoil,palmoil,cottonseedoil,linseedoil,field mustard,palmoil,etc.
SugarcropsSweetsorghum,sugarbeet,sugarcane,etc.
StarchcropsWheat,sweetpotato,corn,rice,barely,maize,etc.
WoodycropsHybridwillow,silvermaple,sweetgum,hybridpoplar,silvermaple, easterncottonwood,blackwalnut,greenash,sycamore,pine, miscanthus,etc.
GrasscropsBamboo,switchgrass,kochia,wheatgrass,canarygrass,coastal Bermudagrass,alfalfahay,thimothygrass,commonreed,Indian shrub,giantreed,immaturecereals,etc.
Agriculturewasteandresidue
Stalk Bean,corn,cotton,kenaf,mustard,sunflower,triticale,etc.
Straw Bean,corn,oat,rice,sesame,sunflower,wheat,mint,paddy,rape, rye,etc.
Shellandhusk
Almond,cashewnut,coffee,olive,peanut,walnut,sunflower, cotton,etc.
Fiber Flax,palm,kneafbast,jutebast,coconutcoir,etc.
LivestockwasteChickenmanure,pigmanure,sheepmanure,cattlemanure,bones, meatbonemeal,etc.
Forestwasteandresidue
Forestwaste Woodblocks,woodchipsfromthinning,logsfromthinning,barks, earlythinningbranches,leaves,bushes,etc.
Industryandmunicipalitywasteandresidue
FoodindustryresidueCookingoil,proteins,tallow,wetcellulosicmaterial(beetroottails), animalfat,oilgheewaste,fruitandvegetablescrap,fiberobtained fromextractionofsugarandstarch,etc.
Paperandwood industryresidue
Fibrouswastefrompaperandpulpindustries,wastewoodfrom sawmills,wastewoodfromtimbermills(bark,woodchips,slabs,and sawdust),paperandpulpsludge,etc.
OtherindustrywasteTanningwaste(leatherparticles,wasteliquor,andfleshingresidue), soapindustry(oilandgrease),wastewatersludge,etc.
MunicipalitywasteSewagesludge,wastepaper,yardwaste,gardengrassesandplants, dairywaste,woodpalletsandboxes,fiberboard,plywood, paperboardwaste,stalefood(uneatenbread,rice,andvegetables), etc.
Marinebiomass
MarinebiomassMarineandfreshwateralgae(microalgaeandmacroalgae), cyanobacteria,marinemicroflora,giantkelp,othermarine microorganisms(marineyeast),duckweed,waterhyacinth,sweet waterweeds,etc.
minimumwaterandnutrientsfortheircultivation.Typicalexamplesoftheseenergy cropsarebamboo,switchgrass,wheatgrass,sweetsorghum,andmiscanthus [4,6]. Theoil,sugar,andstarch-basedcropsarecultivatedacrosstheglobeforfoodpurposes. Theseenergycropsthusposefoodversusfuelconflicts.Somecountries,however,producetheseenergycropsinexcessofhumanconsumptionforbioenergyapplications.For example,Brazilproducessugarcaneforbioethanolproduction.TheIndianGovernment promotedjatrophacultivationinwastelandsforbiodieselproduction.Jatrophaoilisinedibleandhencedoesnotposefoodversusfuelconflict.
Agriculturewastesandresidues.Aconsiderableamountofbiomasswastesandresiduesis coproducedduringtheharvestingofcrops.Theseagro-wasteshave,however,limited utilization.Theyareeitherusedascattlefodderorfuelforcookinginremotevillages. Themajorityofthesebiomassesarestilleitherburnedinthefieldordumpedintothe wasteland.Ricehuskisthemostprominentagro-residue,anditaccountsforabout 25%ofricebymass [7].Sincecornisgrownworldwide,cornstoverisoneofthemajor agro-residues.Animalmanureisalsoincludedinagriculturewastes [4,7].Animal manure,suchascowdung,iscurrentlyusedforbiogasproduction.Theagricultural wastesandresiduesareinedibleandhenceanattractivebiomassforabiorefinery.This biomasshas,however,lowdensityandisgeneratedinremoteagriculturefields.The transportationofthisbiomassfromaremotelocalitytoacentralbiorefineryisthusexpensive.Moreover,thisbiomassisseasonal.Thestoragefacilityforthisbiomassisthusobligatoryfortheuninterruptedoperationofabiorefinery.
Forestwasteandresidue.Forestwastesandresiduesareanotherpertinentbiomass.The loggingresiduesgeneratedfromharvestoperation,fuelwoodderivedfromforestlands, stumps,andearlythinningofbranchesareprimaryforestresidues.Incontrast,woodprocessinggeneratessecondaryresidues.Theseoperationsareessentialtomaintainforest healthandproductivity.Thebarkandwoodhaveahighheatingvalueandaresuitable forthermalenergyapplications.Solidwoodisthemainsourceofenergyforthesmallscaleindustriesinunderdevelopedanddevelopingcountries.Thelowrecoverabilityand costoftransportation,logging,andcollectionactivitiesaremajorhurdlesforthisbiomass. Theutilizationofthisbiomassatornearsourceinadecentralizedbiorefineryisthus desirable.
Industryandmunicipalitywaste.Theorganicchemicalindustriesandmunicipalities generatealargevolumeoforganicwasteswithonlyasmallamountofinorganicmaterials [8].Solidwastes,greenwastes(nutshells,grasscutting,etc.),sewagesludge,andindustry wastesareexamplesofindustryandmunicipalitywaste.Themunicipalitysolidwastes comprisewastefood,paper,plastic,andtextiles.Foodwastesaregeneratedinvarious stepsofthefoodprocessingchain,suchasmanufacturing,logistics,storage,andpostconsumerstage [5,9].Thewastesgeneratedinthepulpindustry,bagasseproducedinthe sugarcaneindustry,andcoproducts(fattyaciddistillate,protein-richcake,gum,soap stock,etc.)oftheoilseedprocessingindustryareexamplesofindustrialwastes.
Marinebiomass.Marinebiomassreferstodiversifiedgroupsofaquaticspecies,photosyntheticalgae,andcyanobacteria.Thesizeofthisbiomassrangesfrommicroscopic(cyanobacteria,microalgae,etc.)tomacroscopic(macroalgaeandbrown,red,blue,andgreen seaweeds).Bothmicroandmacroalgaehavemorethanonemillionspecies [8,10].These speciescouldbeapotentialsourceoftriglycerideandcellulosicbiomass.Theycangrow inwastewater,coastalseawater,salinewater,andnonarableland.Innutrient-richwater, microandmacroalgaegrowwithahighcelldensityofupto107 cells/mL [11].The growthrateofalgaeisalsoveryhighwithashortharvestingcycle(1–10days).
1.2.2Chemistryofbiomass
Thebiomassiscomposedofadiverserangeoforganiccompoundswithaninsignificant amountofinorganicsubstances.Carbon,hydrogen,andoxygenaremajorelementsin biomasswithaminorquantityofnitrogenandsulfur.Carbohydrates,lignin,lipid,proteins,andfatsaremajorconstituentsofbiomass.Theamountoftheseconstituentsinbiomassdependsontheirtypes,growthstage,source,andgeographiclocation.Thefour categoriesofbiomassarecommonlyusedinabiorefinery:triglyceride,sugar,starch, andlignocellulose.
Triglycerides.Thetriglyceridesincludevariousinedibleandediblevegetableoil,waste cookingoil,wasteoils(trapgrease,yellowgrease,etc.),microalgaeoil,andanimalfats. Atriglyceridemoleculecontainsoneglycerolunitandthreesameordifferentfattyacids linkedbyanesterbond(Fig.1.1).Thefattyacidscontainalinearcarbonchaininthe rangeofC8–C24.Palmitic(C16:0),stearic(C18:0),oleic(C18:1),andlinoleic(C18:2)acids areprimaryfattyacidsintriglycerides.Bothsaturatedandunsaturatedfattyacidsarepresentintriglycerides.Thetriglyceridesalsocontainfreefattyacids.Thenumberofdouble bonds,thecarbonchainlengthoffattyacids,andtheextentoffreefattyacidsdependon thetypesoftriglycerides(Table1.2).
Sugarandstarch.Sugar(C12H22O11)ismadeoftwosix-carbonsaccharides,namely α-glucose(C6H12O6)and β-fructose(C6H12O6.).Theyarebondedby α1glucosidic and β2fructosidicbonds(Fig.1.1).Sugarisobtainedfromsugarbeet,sugarcane,sweet sorghum,etc.Ontheotherhand,instarch, α-glucosemonomersarelinkedby α1,4and α1,6glucosidicbondstoformpolymericstructures.Twoprincipalcomponentsare presentinstarch:amylose(20%–25%,water-soluble)andamylopectin(75%–80%, water-insoluble).Amylosecontainsonly α1,4glucosidicbonds,whileamylopectincontainsboth α1,4glucosidicand α1,6glucosidicbonds [4].Starchisfoundinpotato,rice, wheat,beans,etc.
Lignocellulose.Lignocellulosebiomassisacompositeofcellulose(40%–50%),hemicellulose(25%–35%),andlignin(15%–25%)withasmallamountofprotein,pectin,and extractives [4,15] (Fig.1.1).Thecarbohydrates(i.e.,celluloseandhemicellulose) providemechanicalandstructuralstrengthtotheplant,whilethenoncarbohydrate
Amylose
Hemicellulose monomers Starch
Lignin monomers
Fig.1.1 Chemistryofbiomass.
Coumaryl alcohol
Coniferyl alcohol
Table1.2 Chemicalcompositionofbiomass [9,12–14]
Biomass
Vegetableoil,wt%
3.5–7.61.3–6.514–4344–
a C8:0 ¼ 4.6–9.5wt%,C10:0 ¼ 4.5–9.7wt%.
(i.e.,lignin)givesstabilitytothesestructures.Thecompositionoflignocellulosebiomass ispresentedin Table1.2.Celluloseisalong-chainpolysaccharidewithahighdegreeof polymerization(nearly10,000).Itisalinearpolymerof D-glucopyranoseformedby β1,4 glycosidiclinkage.Cellulosehasacrystallinestructurewithfourdifferentforms:Iα,Iβ,II, andIII [16].Thecrystallinestructuresareformedbyintraandintermolecularhydrogen bonding.Thetightpackingofpolymericchainsandcrystallinestructuremakescellulose recalcitrantfordegradationandinsolubleinwater.Inplants,itispresentaselementary fibrilsconsistingofasinglecellulosechainorbundlesofelementaryfibrils,i.e.,microfibrils.Thesecomplexesofferstrengthandchemicalstabilitytoplants [17].
HemicelluloseisabranchedpolymercontainingC5 (xyloseandarabinose,C5H10O5) andC6 (glucose,mannose,andgalactose,C6H12O6)sugars.Thesesugarsareacetylated withuronicacid.Theheterogeneouscombinationofmonosaccharidesinhemicellulose isformedby β1,4glycosidicand β1,3glycosidicbonds.Itisanamorphouspolymerthat canreadilyhydrolyzetomonomersugars [17].Theabundanthemicelluloseinhardwood isxylan,inwhichxylosesugarsarelinkedatoneandfourpositions.Whilesoftwood hemicellulosemostlycontainsglucomannan,apolymerof D-glucoseand D-mannose
bondedby β1,4glucosidicbonds,ligninisabundantinlignocellulosebiomass.Itisanoncrystallineandthree-dimensionalpolymerofphenylpropanoidunits.Thethreeunitsthat formtheligninstructureareconiferylalcohol,sinapylalcohol,andcoumarylalcohol. Thelignincontentandcompositionvarywiththetypesofbiomass.Thehardwoodlignin containsacombinationofconiferyl(25%–50%)andsinapylalcohol(50%–75%).The softwoodligninhasahighpercentageofconiferylalcohol(90%–95%),whilegrasslignin hasallthreebuildingblocks,i.e.,coniferyl(25%–50%),sinapyl(25%–50%),andcoumaryl (10%–25%)alcohol [18]
1.2.3Availabilityofbiomass
BiomassisdistributedinvastterritoriesonEarthwithalargenumberofspecies.Therefore,itisdifficulttoassesstheexactavailabilityofbiomassonarenewablebasis.Ingeneral,wastebiomassfromagriculture,forest,industries,andmunicipalitiesisabundant withoutmuchimpactontheenvironmentandfoodproducts.Thisbiomassisthusappropriateforabiorefinery.In2014,theUnitedStatesconsumed5.6millionmetricton (MMT)cornand0.216MMTbiomasstoproducebio-basedproductsandgasoline blendstocks,respectively [19].In2013,theindustrialsectorintheUnitedStatesutilized approximately85.3MMT(dry)woodandwoodwastetogenerate539trillionBtuthermaland15.4trillionBtuelectricalenergy,whiletheresidentialsectorproduced349.5 trillionBtuthermalenergyfrom44.8MMT(dry)woodandwoodwaste.TheUnited Statesfurthergenerated254MMTmunicipalsolidwastein2013.About34%ofthese wasteswerediscardedforlandfilling,andtheremainingwereusedforeitherenergy recoveryorcompost [19].In2016,theUnitedStatesgeneratedapproximately 3.3MMTwoodpellets.Nearly85%ofthesewereresiduesoriginatedfromthesawmill, woodproductmanufacturing,andlogging,whiletheremaining15%weregenerated fromlogsharvestedforindustrialapplications [20].TheUnitedStatesproposedtogenerate1.3billiontonsdrybiomassby2030forbioenergyapplication.Itincludes87MMT grains,106MMTanimalmanureandfoodprocessingwaste,368MMTforestwaste, 377MMTenergycrops,and428MMTcropresidue [21]
In2017,theglobalbioenergysupplywas55.6EJwith48.2EJcontributionfrom solidbiofuels(woodpellets,woodchips,fuelwood,etc.).Thecontributionsofliquid biofuels,municipalitywaste,biogas,andin dustrialwastewere3.65,1.45,1.33,and 1.07EJ,respectively [22].Ontheotherhand,thecontributionofrenewableelectricity was0.33EJglobally [22] .In2017,biomasssupplied5%oftotalprimaryenergy consumedintheUnitedStateswithabout47%,44%,and10%contributionfrom wood,wood-derivedbiomass,andmunicipalwaste,respectively [23].In2018,the UnitedStatesproduced38.1MMTofoilequivalentbiofuel,whichwasthehighest
intheworld(39.9%).Brazilwastheworld’ssecondhighestbiofuelproducer (21.4MMTofoilequivalent,22.4%) [24,25].
InIndia,theestimatedannualavailabilityofbiomassfromagriculture,forest,and wastelandwas242MMTin2010–2011andisanticipatedtobe281MMTby 2030–2031 [26].RiceandwheatarethemostcultivatedcropsinIndiawhichaccount for41%ofthecultivatedarea,whiletheremaining15.9%,13.8%,and10.2%accountfor oilseed,pulses,andcommercialcrops,respectively [11].In2010–2011,theestimated productionofricestrawwas172.8MMT,ofwhich80.8%and11.1%wereusedasfodder andfuel,respectively,andtheremaining8%wereusedforotherpurposes.About 139.2MMTwheatstrawwasgeneratedin2010–2011,anditisestimatedtobe 193.7MMTby2030–2031 [26].In2015–2016,thetotalcropresiduesinIndiawereestimatedas816.4MMT.Thesugarcaneandcottonresiduesaccountfor282MMT [11,26]. UptoMay2019,theinstalledcapacityofrenewablepowerwas78.4GWinIndiawith 46%,37%,and12.8%contributionfromwind,solar,andbiomass,respectively.India estimatesaprojected175GWrenewablepowerby2022with10GWfrombiomass. Theprincipalfeedstockisbagassefromsugarmills [27].In2015–2019,theaverageannual ethanolconsumptiongrowthwashighercomparedtotheproductiongrowth(8%)in India [27].Thecombinedeffectofenhancedfiscaldeficitowingtotheincreaseincrude oilimportanddepreciatingrupeemakestheIndianGovernmentfocusonbiofuels.The primaryfuelconsumptioninIndiawas809.2MMTofoilequivalent,whichisnearly 5.84%ofglobalconsumptionin2018with27.5MMTofoilequivalentcontribution fromrenewables [25].TheIndianannualbiofuelproductiongrowthrate(19.7%in 2007–2017)washigherthantheglobalgrowthrate(9%).In2018,biofuelproduction inIndiawas1023MMTofoilequivalent,whichwas1.1%ofglobalbiofuelproduction [25].TheNationalBiofuelPolicyinIndiaproposed20%mixingofbioethanolwithgasolineand5%mixingofbiodieselwithdieselby2030 [24,27].During2013–2014,only 1.53%ethanolwasblendedwithgasoline.Itwasincreasedto3.5%in2015–2016and droppedto2.07%in2016–2017 [24].
1.3Biorefinery
Coalisusedmainlytoproduceelectricityinthermalpowerplants.Incontrast,thepetroleumrefineryrefinescrudeoiltoproduceaspectrumofproducts,primarilyfuels,suchas liquefiedpetroleumgas,gasoline,kerosene,jetfuel,diesel,andfueloil.Thesefuelsfind applicationinthetransportationsector,cooking,illumination,andindustry.Besides,the petroleumrefineryproducesnaphthaasfeedstockforpetrochemicalindustries.Onthe otherhand,naturalgasisusedasfeedstockforpetrochemicalindustriesandroadtransportationfuelintheformofcompressednaturalgas.Inthepetrochemicalindustry,naphthaandnaturalgasarefurtherprocessedtoproducethreebasicbuilding-blockchemicals: (i)synthesisgas(H2 +CO),(ii)olefins,suchasethylene,propylene,butylenes,and
Table1.3 Platformchemicals.
Ethanol
Furfural
5-Hydroxymethylfurfural
Furandicarboxylicacid
Glycerolandderivatives
Lacticacid
Isoprene
Biohydrocarbons
Succinicacid
Hydroxypropionicacid/aldehyde
Levulinicacid
Sorbitol
Xylitol
butadiene,and(iii)aromatics,suchasbenzene,toluene,ethylbenzene,andxylenes. Thesebuilding-blockchemicalsarethefoundationfororganicchemicals,fertilizers, polymers,andcommoditiesforoursociety.
Anovelmanufacturingconceptisdevelopingthroughouttheworldtosubstitute thesefossilfuelswithbiomass.Thisconceptisknownasthebiorefinery [3,4].Thebiorefineryshouldideallyproduceaspectrumofproductsthatarecurrentlyobtainedfrom fossilfuels,suchasbiofuels,organicchemicals,polymers,materials,heatenergy,andelectricity.Thebiorefineryidentified12primarybiomass-derivedorganicchemicals,called platformchemicals(Table1.3) [28].Theseplatformchemicalsareproducedfromthe carbohydratefractionofbiomassusingacombinationofchemicalandbiochemicalprocesses.Theglycerolis,however,coproducedinthetransesterificationprocess(10wt%of biodiesel).Theseplatformchemicalshavevastderivativepotentialstoproduceorganic chemicals,polymers,andcommodityproducts.Theplatformchemicalscanalsobetransformedintovariousbiofuels.Thebiorefineryisthusanalogoustotheintegratedpetroleumrefineryandpetrochemicalindustry.Thebiorefinerycanbeclassifiedbasedon eitherfeedstock,products,orthenatureofprocessingtechnologies.Ingeneral,thespecificbiorefineryisexpectedtoprocessbiomasswithasimilarchemicalnature.Sothe biorefineryisspeculatedbasedonthespecificchemicalnatureofbiomass,suchasthe sugarandstarch-basedbiorefinery,lignocellulose-basedbiorefinery,andtriglyceridebasedbiorefinery [3,4].Theseindividualbiorefineriescanbefurtherclassifiedbased oneithertargetedproductsortypesofprocessingtechnologies.
1.3.1Sugarandstarch-basedbiorefinery
Sugarandstarch-basedbiorefineriesarewellknownbecauseofbioethanol.Thestarchbasedfeedstockundergoeshydrolysistoformaqueoussugars.Aqueoussugarsare extractedfromsugar-basedfeedstockthroughphysicalseparationmethods.Aqueous sugarsarefermentedtovastrangesofproducts.Strainsusedinfermentationdetermine thetypesofproducts.Bacterialstrainsareusedforacetone–butanol–ethanol(ABE)fermentationwithcoproductionofhydrogen,whileyeastfermentationyieldsethanol. Bioethanolandbiobutanolareusedasbiofuelandsolvent.Theyarealsoreformedto synthesisgasandcatalyticallyconvertedtopetrochemicalbuilding-blockchemicals,such
asethylene,butylenes,andaromatics [29–31].Fermentationofsugarsalsoproducesvariousplatformchemicals,suchassuccinicacid,lacticacid,glutamicacid,itaconicacid,and 3-hydroxypropanoicacid(Table1.3).Ametabolicallyengineeredstrainproduceslinear orbranchedhigherbio-alcoholsfromsugars.Aqueous-phasecatalysisofsugarsproduces aromaticsandalkanes [32].Hydrogenisproducedbytheaqueous-phasereformingof sugars.5-Hydroxymethylfurfural(HMF)isproducedbydehydrocyclizationofhexose sugars.ThedecompositionofHMFproduceslevulinicacid(LA).Microbialprocessing ofhexosesugarsproducesliquidbiofuels [33]
1.3.2Lignocellulose-basedbiorefinery
Alignocellulosebiomassprovidesawidespectrumofproducts.However,thecomplex structureofthelignocellulosebiomassisthemainbottleneck.Thecombustionofthe lignocellulosebiomassproducesheatandelectricity.Thegasificationproducessynthesis gas,whichisfurtherconvertedtoethanolandhigheralcoholsandliquidbiofuelsthrough theFischer-Tropschprocess.Fastpyrolysisandliquefactionofthelignocellulosebiomass producebio-oil.Bio-oilisupgradedtobiofuels,aromatics,andorganicchemicalsusing hydrodeoxygenation(HDO)andzeoliteupgrading [34].Pretreatmentoflignocellulose biomassformshydrolysatecontainingsugars.Anaerobicfermentationofhydrolysateproducesbiogasandhydrogen.Furtherhydrolysisofpretreatedlignocellulosebiomass reducesthestructuralcomplexityandproducesligninandsugars(hexoseandpentose). Aqueoussugarsarefermentedtoethanol,butanol,acetone,andhydrogen.Aqueousphasedehydration/hydrogenationofsugarsproducesC1–C6 alkanes.Zeoliteupgrading ofsugarsproducesaromaticsandhydrocarbons.Aqueous-phasereformingandmicrobial processingproducehydrogenandliquidbiofuels,respectively [33,35].Furfuraland HMFareC5 andC6 furansandobtainedbydehydrationofC5 andC6 carbohydrates, respectively,inthepresenceofacidcatalysts [36].LAisobtainedbysubsequentdehydrationoffurans.BiofineCorporationproducesLAonalargescaleusingaseriesof tworeactors(70%–80%yield) [37].Inthefirstreactor,carbohydrateisconvertedto HMFat483–503Kinthepresenceofmineralacids.HMFisthenconvertedtoLAin thesecondreactorat468–488Kwithmorethan60%yield.Ligninisconvertedtoaromaticsthroughzeoliteupgrading.Depolymerization,hydrogenation,andsolvolysisof ligningivegasoline-rangefuelandphenolics.
1.3.3Triglyceride-basedbiorefinery
Triglyceridesaretransformedintobiofuels,value-addedproducts,andorganicchemicals. Thecakeorresidueobtainedfromoilseedisusedasfertilizer,feed,orfeedstockstothe lignocellulosebiorefinery.Transesterificationoftriglyceridesforbiodieselproduction hasgainedenormousattentioninthisbiorefinery.Hydrolysisoftriglyceridesproduces
Table1.4 Classificationofbiorefinerybasedontypesofbiofuels.
Biorefinery
Biorefineryfor traditionalbiofuels
Biorefineryforfueladditives
Hydrocarbon biorefinery
Biofuels
Biodiesel,bioethanol,biobutanol,dimethylether,etc.
γ-Valerolactone,furaniccompounds(2-methylfuran, 2-methyltetrahydrofuran,2,5-dimethylfuranand2,5dimethyltetrahydrofuran),5-ethoxymethylfurfural,alkyllevulinates, glycerolether/acetal,etc.
Greenliquefiedpetroleumgas,greengasoline,greenkerosene, greenjetfuel,greendiesel,etc.
Fig.1.2 Biorefineryfortraditionalbiofuels.
fattyacidsthatarehydrogenatedandisomerizedtogreendiesel [38].Fattyacidsarealso usedtoproducemanyvalue-addedproductslikesoaps,emulsifiers,surfactants,etc. GreendieselandgreengasolinearealsoproducedbydirectHDO,catalyticcrackingover solid-acidcatalysts,andpyrolysisoftriglycerides [39].Steamanddryreformingoftriglyceridesproducesynthesisgas [40,41]
1.3.4Biorefineryforbiofuels
Thebiorefinerycanbebroadlyclassifiedintothreetypesbasedonthenatureofbiofuels produced:(i)biorefineryfortraditionalbiofuels,(ii)biorefineryforfuel-additives,and (iii)hydrocarbonbiorefinery(Table1.4) [42].
1.4Biorefineryfortraditionalbiofuels
Thebiorefineryfortraditionalbiofuelsisshownin
Fig.1.2.Thefuelpropertiesofthese biofuelsarecomparedwithgasolineanddiesel,aspresentedin Table1.5.
