BIOFUELSAND BIOREFINING Volume1:Current TechnologiesforBiomass
Editedby
FERNANDOISRAELGÓMEZCASTRO
CLAUDIAGUTIERREZ-ANTONIO
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Contributors
SergioValdirBajay CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
SudhanshuS.Behera DepartmentofBiotechnology,NationalInstituteofTechnology,Raipur,Chhattisgarh; AyurinnoLegacyOPCPvt.Ltd.FTBI,NationalInstituteofTechnology,Rourkela, Odisha,India
MauroDonizetiBerni CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
Adria ´ nBonilla-Petriciolet InstitutoTecnolo ´ gicodeAguascalientes,Aguascalientes,Mexico
ValeriaCaltzontzin-Rabell EngineeringSchool,AutonomousUniversityofQueretaro,Queretaro,Mexico
WedjadaSilvaClementino FacultyofMechanicalEngineering(FEM),UniversityofCampinas(Unicamp),Campinas, SP,Brazil
LauraCondeBa ´ ez BiotechnologyEngineering,PolytechnicUniversityofPachuca,Hidalgo,Mexico
CarolinaCondeMejı ´ a MultidisciplinaryAcademicDivisionofJalpadeMendez,JuarezAutonomousUniversityof Tabasco,Tabasco,Mexico
JavierFontalvo
GrupodeInvestigacio ´ nenAplicacio ´ ndeNuevasTecnologı´as(GIANT),Departamentode Ingenierı´aQuı´mica,UniversidadNacionaldeColombia,Manizales,Caldas,Colombia
LucasTadeuFuess
ChemicalEngineeringDepartment(DEQ),PolytechnicSchool(EP),UniversityofSa ˜ oPaulo (USP),Sa ˜ oPaulo,SP,Brazil
FernandoIsraelGo ´ mez-Castro DepartmentofChemicalEngineering,DivisionofNaturalandExactSciences,University ofGuanajuato,Guanajuato,Mexico
Vı´ctorHugoGrisales-Dı ´ az Grupodeinvestigacio ´ nenMicrobiologı´ayBiotecnologı´a(MICROBIOTEC),Facultadde CienciasdelaSalud,UniversidadLibreSeccionalPereira,BelmonteAvenidaLasAmericas, Pereira,Risaralda,Colombia
ClaudiaGutierrez-Antonio
EngineeringSchool,AutonomousUniversityofQueretaro,Queretaro,Mexico
NilsRandulfKristiansen
DepartmentofEngineeringSciences,UniversityofAgder,Grimstad,Norway
RubensAugustoLamparelli
CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
XueLi
CleanTechnology,BioproductsandBioprocessNationalScienceProgram,SaskatoonResearch andDevelopmentCentre,ScienceandTechnologyBranch,GovernmentofCanada,Saskatoon, SK,Canada
PauloCesarManduca
CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
SergioIva ´ nMartı´nez-Guido
EngineeringSchool,AutonomousUniversityofQueretaro,Queretaro,Mexico
OsirisMartı´nez-Sa ´ nchez
DepartmentofChemicalEngineering,DivisionofNaturalandExactSciences,Universityof Guanajuato,Guanajuato,Mexico
GilbertoMartins
Engineering,ModelingandAppliedSocialSciencesCenter(CECS),FederalUniversityofABC (UFABC),SantoAndre,SP,Brazil
BrunadeSouzaMoraes
CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
RicardoMorales-Rodriguez
DepartamentodeIngenierı´aQuı´mica,Divisio ´ ndeCienciasNaturalesyExactas,Campus Guanajuato,UniversidaddeGuanajuato,Guanajuato,Mexico
AnaLauraMoreno-Go ´ mez
InternationalBusinessDepartment,PolytechnicalUniversityofSaintRoseJa ´ uregui,Queretaro, Mexico
EdmundMupondwa
CleanTechnology,BioproductsandBioprocessNationalScienceProgram,SaskatoonResearch andDevelopmentCentre,ScienceandTechnologyBranch,GovernmentofCanada; DepartmentofChemicalandBiologicalEngineering,UniversityofSaskatchewan,Saskatoon, SK,Canada
SilviaAzucenaNebra
CenterforEnergyPlanning(NIPE),UniversityofCampinas(Unicamp),Campinas,SP,Brazil
HenrikKofoedNielsen DepartmentofEngineeringSciences,UniversityofAgder,Grimstad,Norway
ReynaldoPalacios-Bereche
Engineering,ModelingandAppliedSocialSciencesCenter(CECS),FederalUniversityofABC (UFABC),SantoAndre,SP,Brazil
OscarAndresPrado-Rubio
GrupodeInvestigacio ´ nenAplicacio ´ ndeNuevasTecnologı´as(GIANT),Departamentode Ingenierı´aQuı´mica,UniversidadNacionaldeColombia,Manizales,Caldas,Colombia; DepartmentofChemicalandBiochemicalEngineering,TechnicalUniversityofDenmark, PROSYS—ProcessandSystemsEngineeringCentre,Lyngby,Denmark
NellyRamı´rez-Corona DepartmentofChemical,FoodandEnvironmentalEngineering,UniversidaddelasAmericas Puebla,Puebla,Mexico
RameshC.Ray
CentreforFoodBiologyandEnvironmentStudies,Bhubaneswar,Odisha,India
AraceliGuadalupeRomero-Izquierdo EngineeringSchool,AutonomousUniversityofQueretaro,Queretaro,Mexico
AngelaV.Ruales-Salcedo
GrupodeInvestigacio ´ nenAplicacio ´ ndeNuevasTecnologı´as(GIANT),Departamentode Ingenierı´aQuı´mica,UniversidadNacionaldeColombia,Manizales,Caldas,Colombia
SoumanRudra
DepartmentofEngineeringSciences,UniversityofAgder,Grimstad,Norway
P.Saranraj
DepartmentofMicrobiology,SacredHeartCollege(Autonomous),Tirupattur,TamilNadu, India
AriovaldoJoseSilva
SchoolofAgriculturalEngineering(FEAGRI),UniversityofCampinas(Unicamp),Campinas, SP,Brazil
LopeTabil DepartmentofChemicalandBiologicalEngineering,UniversityofSaskatchewan,Saskatoon, SK,Canada
ToreSandnesVehus DepartmentofEngineeringSciences,UniversityofAgder,Grimstad,Norway
JianlongWang
TsinghuaUniversity – ZhangJiagangJointInstituteforHydrogenEnergyandLithium-Ion BatteryTechnology;CollaborativeInnovationCenterforAdvancedNuclearEnergy Technology;BeijingKeyLaboratoryofRadioactiveWasteTreatment,INET,Tsinghua University,Beijing,People’sRepublicofChina
YananYin
TsinghuaUniversity – ZhangJiagangJointInstituteforHydrogenEnergyandLithium-Ion BatteryTechnology;CollaborativeInnovationCenterforAdvancedNuclearEnergy Technology,INET,TsinghuaUniversity,Beijing,People’sRepublicofChina
Biomass:Thedriverforsustainable development
FernandoIsraelGómez-Castroa andClaudiaGutierrez-Antoniob aDepartmentofChemicalEngineering,DivisionofNaturalandExactSciences,UniversityofGuanajuato,Guanajuato,Mexico bEngineeringSchool,AutonomousUniversityofQueretaro,Queretaro,Mexico
1.1Introduction
Until2019,theeconomicsectorsshowedeconomicgrowthasresultofpopulation increase.Similarly,globalizationcontributedtosuchgrowbyallowingfreetradeatan internationallevelataffordablepricesandminimumdeliverytimes.Accordingtothe WorldBank,theworldgrossdomesticproductduringtheperiod2010–2019augmented 32.77%,from66,126to87,799billionUSD(WorldBank,2021a).Nevertheless,in 2020,theemergenceandspreadofthesevereacuterespiratorysyndromecoronavirus 2(SARS-CoV-2)changedtheworldscenario(Liu,Kuo,&Shih,2020).Theeasyspread ofthevirusgeneratedapandemic,forwhichtherewasnovaccineavailable.Therefore, preventionmeasuresincludedisolatingthepopulation,whichledtochangesinconsumptionpatternsandthebreakdownofsomesupplychains( Jiang,Fan,&Klemes ˇ , 2020).Althoughtheisolationmeasurescontributedtosavingpeople’slives,whichare invaluable,thishasundoubtedlysloweddownthedevelopmentofeconomicsectors. Ontheotherhand,beforethepandemicsocietyfacedtheclimatechangeproblem, whichiscausedfortheaccumulationofgreenhousegasesintheatmosphere.According tothe InternationalEnergyAgency[IEA](2021a),theglobalcarbondioxideemissions increasedin9.5%duringtheperiod2010–2019,from30.4to33.3Gt.In2020,theemissionsdecreasedalmost8%respectto2019(IEA,2021b).Nevertheless,theforecastsindicatedthattheglobalenergydemandcanreboundtoitspre-pandemiclevelsbetween 2023and2025withaprojectedgrowthforenergydemandbetween9%and4%,respectively(IEA,2021c);thedifferencebetweentherecoverytimeandprojectedenergy demandreliesintheimplementationofcleantechnologies.
Inthiscontext,theIEA,incollaborationwiththeInternationalMonetaryFund,proposedaSustainableRecoveryPlantobeappliedintheperiod2021–2023(IEA,2021d). TheSustainableRecoveryPlanconsiderasmainobjectivesboostingtheeconomic growth,creatingjobs,andbuildingmoreresilientandcleanerenergysystems.Theplan includespolicies,investmentsandmeasurestoacceleratethedeploymentoflow-carbon electricity,increasethespreadofcleanertransport,improvetheenergyefficiencyof
BiofuelsandBiorefining Copyright © 2022ElsevierInc. https://doi.org/10.1016/B978-0-12-824116-5.00008-8
Fig.1.1 SustainablerecoveryplantproposedbytheIEA,incollaborationwiththeInternational MonetaryFund(IEA,2021d).
buildingsandappliances,enhancetheefficiencyofequipmentusedinindustries,developmentofsustainableproductionofbiofuels,andboostinnovationincrucialtechnology areas(IEA,2021d), Fig.1.1.
TheSustainableRecoveryPlanemphasizethepromotionanduseofcleanenergy projects,whererenewableenergysourceshaveakeyrole.Amongrenewableenergy sourcesthesolarradiation,geothermalenergy,windstreams,marinestreams,hydroenergy,andbiomass,areincluded(Fig.1.2).
Solarradiationincludestheheat,light,andotherradiationgivenbythesun,which emits8.65 1013 TW;however,only173,000TWarrivetotheearth(Book,2002);as reference,in2018theglobalpowergenerationwas26,603TW(Kober,Schiffer, Densing,&Panos,2020).Itmustbementionedthatahighfractionofthesolarradiation arrivingtheearthisreflected,around52,000TW(Book,2002).Moreover,theamount ofsolarradiationthatisabsorbeddependsontheanglebetweenthedirectionofthesun andthesurface,thepresenceofclouds,aswellastheabsorbedfractioninthatsurface (Dickinson,2003).Duetothis,solarradiationisnotequallyavailableinalltheregions oftheplanet;thus,minorradiationsolarisreceivedinhighlatitudes,andmajorinthe tropics(Dickinson,2003).Amapofworldwidesolarradiation,developedbytheWorld BankandtheInternationalFinanceCorporation,istheGlobalSolarAtlas(WorldBank
Biofuels
Recovery Plan
Group,2021a).Thesolarradiationcanbeconvertedthroughelectricalenergy,through photovoltaicpanels,andthermalenergy,throughsolarabsorberdevices.
Ontheotherhand,themovementofwindstreamsisanotherrenewableresource, derivedfromthesolarradiation.Accordingto Book(2002),370TWfromthetotalsolar radiationaretransferredtowindandwaves.Thewindstreamscontainrenewableenergy generatedfromthepressuredifferenceofnaturalwarmandcoolareas,whichcreatesair massesinconstantmovement(Yahyaoui,2017).Therefore,likethesolarirradiation, windstreamsareavailableinalltheplanet,butatdifferentspeedsanddensities. Amapofworldwidewindstreams,developedbytheWorldBankandtheInternational FinanceCorporationalongwiththeTechnicalUniversityofDenmark,istheGlobal WindAtlas(WorldBankGroup,2021b).Accordingtothe IEA(2021e),theleadregions inuseofwindenergyin2019wereChina(23.8GW),theEuropeanUnion(10.5GW), theUnitedStates(9.1GW),India(2.4GW),andLatinAmerica(2.2GW).Thewind energycanbeconvertedintoelectricalenergy,throughwindgenerators,orinto mechanicalenergy,throughwindmills.
Themarinestreamsalsocontainenergy,whichisderivedfromthesolarradiation. Accordingto Book(2002),370TWfromthetotalsolarradiationaretransferredtowind andwaves.Themarineenergyincludestidalenergy,waveenergy,andthosederived fromtemperatureandsalinitydifferences(Liu,2015).Themarineenergyisnotavailable inalltheregionsoftheplanet;inthoseregionswhereisavailable,differentenergydensitiesareobserved.Thetheoreticalreservesofmarineenergyareestimatedin 76,600GW,fromwhich52.2%and39.1%proceedfromtemperaturedifferencesand oceansalinity,respectively;tidalandwaveenergyonlycontributewith3.9%each
Fig.1.2 Renewableenergysources.
one,whiletheoceancurrentenergywithbarely0.9%(Liu,2015).TheGlobalAtlasfor RenewableEnergycontainsaworldwidemapofmarinetidalcurrents(IRENA,2021). Theenergycontainedinthemarinestreamscanbeconvertedtoelectricalenergy throughbuoys,turbines,floatingtubes,andmembranes.
Moreover,hydro-energyistheformofenergywhichcouldbeharnessedthrough movementofwatertopowermach ineryorcreateelectricity( Ratlamwala&Dincer, 2018 ).Usually,awatercourseiscollectedatahighlevelandreturnedatalower level,theleveldifferencescanbefromseveralmeterstoamaximumof1800m ( Gardel,1981 ).Thehydro-energyisnotavailableinalltheregionsoftheplanet; inthoseregionswhereisava ilable,differentpotentialsforenergyproductionare observed.Accordingto Breeze(2019) ,theglobalcapacityofhydro-energyisaround 1300GW.Thepotentialenergyaccumulatedinthereservoirsistransformedto kineticenergyandlaterinelectricitythroughhydropowerplants;theseplantscan beclassifiedasmicro(productioncapacity upto100kW),small(productioncapacity upto5MW),medium(productioncapacit yupto100kW),andlarge(production capacitygreaterthan100kW).
Ontheotherhand,geothermalisthermalenergygeneratedandstoredintheEarth. Suchkindofenergyisoriginatedfromtheprimalformationoftheplanet(20%)andfrom radioactivedecayofminerals(80%)(ElBassam,Maegaard,&LawtonSchlichting,2013). Geothermalenergyistheonlyrenewableenergysourcethatdoesnotrelyonthesunas primaryenergysource(Fekete,2013).Accordingto Kammen(2004),1%oftheheat containedintheuppermost10kmofEarth’scrustisequivalentto500timestheenergy containedinallofEarth’soilandgasresources;however,itisunevenlydistributed,seldomconcentrated,andoftenatdepthstoogreattobeexploited.Aworldwidemapthat showsthelocationofthisrenewableresourceisavailable(GeothermalEnergyMap, 2021).Thegeothermalenergycanbeconvertedintoelectricalenergy,throughpower generationfacilities,andintothermalenergy,throughheatexchangersandheatpumps.
Finally,biomassisacomplexnaturalrenewablematerialwithenormouschemical variability(Bonechietal.,2017),anditisavailableinalmostanyplaceoftheplanet. Accordingtothe WorldBioenergyAssociation(2020),theworldwidetotallandarea availableisabout13billionhaoutofwhichagriculturelandaccountsfor37%(4.8billion ha),forestlandaccountsfor31%(3.9billionha)andotherlandcoversabout32%(4.2 billionha).Aninterestingcharacteristicofbiomassisthatcanbeusedtoproducethermal andelectricalenergy,aswellasbiofuelsandvalue-addedproducts.Duetothis,biomassis themostpromisingrenewableresource,whichcanbeamaindrivertowardthesustainabledevelopment.
Therefore,inthischapter,thecurrentsituationontheenergeticandtransportation sectorswillbedescribedtojustifythenecessitytomovetoabiomass-basedeconomy. Finally,futureinsightsonthedevelopmentofabiomass-basedeconomywillbe presented.
1.2Globalenergycontext
Inthelastyears,theuseofenergyinalltheeconomicsectorshasconsiderablyaugmented; thisincrementismainlyduetothegrowthofpopulationaswellaschangesinthelifestyle ofsociety.Thephenomenonofglobalizationhasacceleratedtheadoptionofonlineplatformsforalmosteveryactivityindailylife;theseplatformsoperatethankstothepresence ofservers,storagesystems,andnetworksallovertheworld.Indeed,thepandemicthatwe areexperiencinghascontributedtothis,duetothesocialisolationmeasuresthathave beenrequestedtoreduceinfections.
In2010,theworldwideenergyconsumptionwas8837.84Mtoe(IEA,2021f),while thesedataincreasedto14,406Mtoein2019(IEA,2021g),whichrepresentagrowthof 63%;ontheotherhand,thepopulationincreasedfrom6956.82millionto7713.46duringthesameperiod,whichrepresentsjustagrowthof10.87%(WorldBank,2021b).
Table1.1 showstheobservedchangeinthecontributionofeachtypeoffuelinthe worldwideenergyconsumption.Weobservethatthecontributionofrenewableenergies augmentedin226%duringtheperiod2010–2019,whiletheuseofbiomassintraditional way(firewood)decreasedin18.49%.Ontheotherhand,theuseofcoalandoilincreased in51.36and57.90%,respectively.Thehigherincrementsinnon-renewablesources wereobservedinnuclearandnaturalgaswith63%and78.52%,respectively.
In2020,therewasadecreasingin5%intheworldwideenergydemand,anditis expectedthattheenergydemandlevelsobservedin2019canbereachedbetween 2022and2025(IEA,2021h);asitwasmentioned,thedifferencebetweentherecovery timeandprojectedenergydemandreliesintheimplementationofcleantechnologies.It isimportanttomentionthatintheforecasts,until2030,thereisanestimatedgapof3% and8%respecttothepre-crisistrajectoryfortherecoveryyearsof2022and2025,respectively(IEA,2021h).Nevertheless,itisexpectedanincreasinginenergydemand,andas consequenceincarbondioxideemissions.Therefore,itisnecessarythedevelopmentof
Table1.1 Totalenergyconsumptionfortypeoffuelbetween2010and2019. Typeoffuel2010(Mtoe)2019(Mtoe)Variation(%)
Nuclear530.27864.36+63.00
Biomass707.03576.24 18.49
Renewables441.891440.6+226.00
Naturalgas1855.953313.38+78.52
Oil2828.114465.86+57.90 Coal2474.603745.56+51.36 Total8837.8414,406.00+63.00
Datawastakenfrom: InternationalEnergyAgency(2021f). Worldtotalfinalconsumptionbysource 1973–2018 https://www.iea.org/data-and-statistics/charts/world-total-final-consumptionby-source-1973-2018 (accessed15.03.2021);InternationalEnergyAgency(2021g). World energyoutlook2020 https://www.iea.org/reports/world-energy-outlook-2020#executivesummary (accessed15.03.2021).
Fig.1.3 Numberofarticlespublishedrelatedtosustainabilityandtherenewableresources. (Data source: www.sciencedirect.com.)
strategiesthatcontributetothesustainablerecoveryofalltheeconomicsectors worldwide.
Sustainabledevelopmentimpliesmeetingtoday’sneedswithoutdeprivingfuture generation’sabilitytomeettheirownneeds(Bilgili&Ulucak,2020).Thus,itisnecessary tocontinuethetransitionfromnon-renewabletorenewableresources.Thisnecessity appliesnotonlyforenergetics,instead,itincludesalltheproductsderivedfromnonrenewableresources,suchassolvents,polymers,lubricants,additives,chemicals,textile, fertilizers,aswellasenergystoragedevices.Inthiscontext,biomassisapromissoryalternativetowardthissustainabledevelopment;duetothis,theeffortsofthescientificcommunityarefocusedonbiomassovertheotherrenewableresources. Fig.1.3 presentsthe numberofarticlesintheElsevier’ssearchplatform(www.sciencedirect.com),which resultedfromthecombinationofthewords“sustainability”plusthetypeofrenewable resource.Asimilartrendisobservedifthewordsustainabilityisremovedfromthesearch box.Inparticular,thenumberofarticlesrelatedwithbiomassandsustainabilityhas grownexponentially;in Fig.1.4,wecanobservehowthisnumbervariedfrom1384 in2000to19,978in2020,datawhichrepresent14.42timesthenumberin2000.This evidencestherelevanceofbiomassasakeyrenewableresourcenotjustforenergyproductionandstorage(Antaretal.,2021; Awasthietal.,2020; Kumar&Verma,2021; Senthil&Lee,2021),butalsoforvalue-addedproducts(Antaretal.,2021; Kobayashi&Nakajima,2021; Sen&Baidurah,2021; Usmanietal.,2021).
Fig.1.4 Historicalevolutionofthenumberofarticlespublishedrelatedtosustainabilityandbiomass. (Datasource: www.sciencedirect.com.)
Thebiomassisarenewableresourcewhichcanbeconvertedtoawidevarietyof value-addedproductsaswellasseveraltypesofbioenergy.Nevertheless,itsrenewable characterdoesnotautomaticallyimplythatisenvironmentallyfriendly.Indeed,allthe productionprocesseshaveanenvironmentalimpact,andbiomassconversionisnot theexception.Accordingto Sayedetal.(2021),someoftheenvironmentalimpactof biomassuseincludeexhaustiveutilizationoflandandresources,highsoilerosionrates, decreaseinwatercatchmentforaquiferrecharge,lossofsoilnutrients,andreductionof biodiversity.Nevertheless,thebiomassusagediminishesgreenhousegasesaswellasthe ecologicalfootprint,beingthelastonetherelevantindicatortoanalyzetheenvironmentalsustainability(Bilgili&Ulucak,2020).Therefore,theresearchanddevelopment effortsmustbefocusedontheuseofwastebiomass,avoidingthecompetitionwithfood andsolvingapollutionproblem;moreover,theextractionand/ortransformationprocessesforbiomassmustbeofminimumenergyconsumptionand,aspossible,ofzero residues.Inthiscontext,theuseofprocessintensificationaswellasbiorefineryproductionschemesarepromissorystrategiestoachievesustainableprocessfortheconversionof biomassintovalue-addedproductsaswellasbioenergy.Moreover,itiscriticaltodevelop toolstoovercomethebiomasssupplychainplanningchallenges,inordertominimizethe
environmentalimpactandmaximizethesocialandeconomicbenefits(Zahraee, Shiwakoti,&Stasinopoulos,2020).Thisisthefocusofthetwovolumesofthisbook.
Inaddition,anotherimportantaspectistheestablishmentofpolicies,whichare definedbygovernmentsorpartiesastheprinciplesthatguidedecision-makingtoachieve anobjectiveorgoal.Inthiscontext,severalstudiescanbefoundrelatedtotheeffectsof governmentpoliciesonsustainabilityinseveralcountries.Someoftheseworksas describednext.
Umar,Urmee,andJennings(2018) proposedapolicyforthegenerationofelectricity basedonoilpalmbiomassinMalaysia.Thepolicyincludesninedrivers:policiesandacts onrenewableenergy,biomasswastemanagement,ruralelectrification,environmental,as wellasbiomassfinancingpolicy,electricitysupplyact,Feed-inTariffsystem,physical infrastructuresystemalongwithanawarenesscampaign.Theauthorsalsoconcludethat Governmentinterventionisnecessarytoattracttheinvolvementofleadingcompaniesin thebusiness. BishtandThakur(2019) reportedtheeffectofgovernmentpolicyforthe generationofelectricitythroughsmall-scalebiomassgasificationplantsinIndia.Authors indicatedthattheGovernmentofIndiapromotesbiomassgasificationprojectforthermal andelectricalenergygenerations(until5MW),ascapitalsubsidies.Inaddition,attractive fiscalincentivescanbeobtainedduring10yearsforthistypeofprojects.Theauthors affirmthatthegovernmentpolicyhasledtothegrowthofthesectoratarateof 0.81GW/year.RespecttoChina, Guanetal.(2020) developednewrecommendations forthedevelopmentofbiomassmoldedfuelinChina;thebiomassmodeledfuelincludes pellets,briquettes,androds.Theauthorsmadeananalysisofthecurrentpolicies,suggestingsomeimprovements.Theymentionedthatitisnecessarytoimprovethelegislationsystem,sincetherearenotspecificbiomassenergylawsinChina;also,effective economicincentivesmustbeimplemented,suchasinvestmentloans,taxdeductions, andreinvestmenttaxrefund.
ShehuandClarke(2020) reportedthatthelackofpolicyisoneofthemainnontechnologicalbarriersfortheestablishmentofbiofuelsindustryinAfrica,andparticularly inNigeria.TheyanalyzedtheuseofJatrophaandpalmoilsfortheproductionofbiodieselinNigeriaconsideringcropyield.Thus,theyproposedtheimplementationofthe intersectoralpolicyleadbytheFederalMinistryofEnvironment,whichcouldhelptothe sustainabledevelopmentofthecountry,helpingtotheenergydiversification.
InBangladesh,therearepoliciestoreducethegreenhousegasemissionslevels.In spiteofthis,theemissionslevelshadincreased.Thus, Hasanetal.(2020) realizedastudy toevaluatedhowthesepoliciescouldbeimprovedinordertobeeffectiverespectthe nationalobjectives.Theyfoundthatpoliciesonrenewableenergy,energyefficiency anddemandmanagement,andafforestationcontributedtothenationaldevelopment goals,whilethosepoliciesrelatedwiththeelectricitygenerationfromcoalandforestbiomasshavelittlesynergywiththegoals. Nong,Nguyen,Nguyen,Wang,andSiriwardana (2020) presentedacriticalreviewofthepolicieseffects,andotheraspects,onthe
sustainableeconomyinVietnam.Inspiteoftheavailabilityofnaturalresources,thereis stillmissingfinancialcapacities,advancestechnologiesaswellasqualifiedhuman resources.Moreover,authorsidentifiedthattheGovernmentofVietnamneedtoarticulateaclearpathwaytoinformtheenergysectorstobecomemoremarket-drivenalong withaclimatechangepolicy,suchascarbontaxoremissionstradescheme.
Recently, Cross,Welfle,Thornley,Syri,andMikaelsson(2021) realizedastatistical analysisoftheeffectsofbioenergypoliciesintheUnitedKingdom,Denmark,Finland, andSweden.Allthesecountrieshaveseveraltargets,relatedtorenewableelectricity (oscillatebetween7%and23%)andheat(between8%and56%).Authorsconcludedthat theachievementinbioenergytargetsdependsonmanyfactorssuchasenergy,economic andenvironmentallandscapeofeachcountry,andnotexclusivelyofthegovernment policy.TheirresultsalsoshowedthatUnitedKingdomhasbeensuccessfultoreach itsrenewableelectricitytargets,whiletheNordiccountrieshavesuccessfullyaccomplishedtheirrenewableheattargets.Ontheotherhand, Singh,Christensen,and Panoutsou(2021) reviewedtheEuropeanpoliciesrelatedtothebiomassvaluechains withtheobjectiveofevaluatehowalignedtheyarerelatedwiththefivecoreobjectives proposedinthe2018BioeconomyStrategy.Authorsreportedthatitisnecessaryto implementpoliciestoproportionatefinancialsupportthatpromotescollaboration betweentheactorsofthesupplychain.Therefore,theyrecommendedsomeupdates inthesepolicies,introducingfinancial,regulatory,orinformationprovisions.
Chang,Liu,Khan,andLiu(2021) analyzedthelegalsystemoftheUnitedStatesfor thedevelopmentofmarinerenewableenergy.Accordingtotheauthors,thelegalframeworkisadequateforthedevelopmentofthistypeofrenewableenergy;however,the authorsrecommendtheimprovementoftheinstitutionalstructureinordertoreach theestablishedgoals.
ForGermany, Rechsteiner(2021) presentedacompleteanalysisoftheenergytransition.Forthiscountry,thedrivendidnotproceedfromadisruptivetechnologyorthe abundanceofanaturalresourceforenergyproduction.Instead,thedeterminingfactor fortake-offwasofaninstitutionalnature,basedonchangestolawsontariffsandnew, openmarketstructures(Rechsteiner,2021).Thus,aminimumpricewasofferedfor renewableenergy,whichimpulsethatthecitizensinvertedinrenewabletechnologies, mainlyphotovoltaicandwind.Inthesameyear, Erat,Telli,Ozkendir,andDemir(2021) realizedacriticalanalysisoftheenergytransitioninTurkey.Theauthorsreportedthat thegoalssettledfor2023regardtheuseofrenewableenergyhavealreadyreached;in spiteofthis,thecountryhasabiggerpotentialtoimplementrenewableenergy.Thetargetsfor2030includetheincreaseoffacilities’capacitiesintheuseofsolar(38,000MW), wind(25,000MW),andgeothermal(4000MW).Later,ananalysisofthestrategies,policies,andresultsoftheenergytransitionofTurkeyandGermanywerepresentedby Telli, Erat,andDemir(2021).Bothcountrieshaveshownimportantadvancesintheirenergy transition,inspiteofthedifferencesintheeconomicandgeographicconditions;
moreover,GermanyandTurkeyarecommittedtoreduceitscarbondioxideemissionsin 80%(2050)and21%(2030),respectively.ThemaindifferencereliesinthatGermanywill shutdownthenuclearpowerin2022,whileTurkeywillhavenuclearpowerinthe energyportfolioin2023.
Finally, Buiraetal.(2021) proposedadecarbonizationpathwayinMexico.Authors indicatedthattheactualMexicanpolicyisnotcompatiblewiththegoalsofParisAgreement.TheyproposedpoliciestoaccomplishthedecarbonizationofthemaincontributingsectorsinMexico.Someofthesepoliciesincludepromotingtheinvestmentto expandtherenewablegenerationcapacity,developmentofurbanizationandpublic transportstrategies,suspendinginvestmentsinoilandgasprojects,andestablishprograms toreduceemissionsinagriculturethroughtheimplementationofthebestpractices.
Basedonthepreviousworks,itcanbeobservedthateachcountryhasuniquecharacteristicsthatleadtodifferentopportunityareasfortheestablishmentofbiomassvalue chains.Eachcountrymustproposeitsbiomassusagetargetsbasedonthoseavailable.The governmentpoliciesdonothaveauniquecorrelationwiththeachievementofbioenergy targets;however,itisimportanttocountwiththemsincetheyestablishthetargetsand followtheadvancesontheiraccomplishment.Basedonthat,alltheprogramsandeconomicincentivesmustbeimplementedinordertoachievethegoals.Moreover,thereis animportanttaskonthecommunicationofthecurrentscienceandtechnologydevelopments,toallowallthepopulationknowabouttheadvantagesonmovingtoabiomassbasedeconomy.Also,itisnecessarytoidentifythemostviablebiomassthatisgoingtobe requiredwithoutaffectingthefoodsafetyandconsideringtheclimateconditionsineach country.Theseaspectswillbediscussedinthenextsection.
1.3Biomassforbioenergyandvalue-addedproducts
Accordingto Houghton(2008),theterm“biomass”referstothemassofalllivingorganisms,includingplants,animals,andmicroorganisms.Particularly,plantbiomasshas playedanimportantroleinthehistoryofmankind,beingoneofthefirstwaystodeliver energy,asoccurswhenburningwood.Throughphotosynthesis,plantscapturesolar energyandcarbondioxide,obtainingavarietyofcarbon-containingproducts,e.g.carbohydrates(Zhu,Long,&Ort,2008).Thus,plantbiomasshaspotentialtobearenewablesourceofenergyandasinkforcarbondioxide.Nevertheless,thecomponentsofthe plantbiomassmustbemodifiedforamoreefficientproductionofbioenergy.Asexample,directburningofagriculturalresiduesisfeasible;indeed,itisacommonpracticein somecountries.Nevertheless,suchresiduesstillhavehumidity,reducingthecombustion efficiency.Suchburningpracticesreleasegreatamountsofgreenhousegases.Other exampleistheuseofwoodasfuel.Adisadvantageofsuchapproachisthedeforestation, causedbythehighdemandofenergyandthelowgrowingrateofatree.Thus,plant biomasscouldbekeyforasustainabledevelopment,butitmustbemodifiedtomake
Table1.2 Typesofbiomassintermsoftheirchemicalcomposition.
Typeofbiomass Maincomponents
Sugar/starchy Sugar
Starch
Lignocellulosic Lignin
Hemicellulose
Cellulose
Triglyceride-based Triglycerides
Freefattyacids
abetteruseofitsenergycontent.Theuseofnewtechnologiescouldbefavorable;for instance,theuseofecologicalstovesallowsthedirectwoodburninginamoreefficient way.Moreover,theremustbeaproperplanningforbiomass’useasenergysource,to allowsatisfyingthedemandbutmaintainingtheavailabilityoftheplantsandother renewableenergysources.
Plantbiomasscanbeclassifiedeitherintermsofitschemicalcharacteristicsoritsorigin.First,thekindsofbiomassintermsoftheirchemicalcompositionaredescribedin Table1.2.Sugar/starchybiomassincludescorn,sugarcane,sugarbeet,amongothers. Thecarbohydratesarealmostdirectlyavailableinthiskindofbiomass,sotheycanbe easilyreachedtoobtainderivatives.Amonglignocellulosicbiomass,agriculturalresidues canbementioned.Lignocellulosicbiomasshasacomplexstructure,whichmakesmore difficulttoreachthefractionfromwhichusefulderivativesareobtained.Ontheother hand,triglyceride-containingbiomassincludecanola,sunflower,castor-oilplant,and otherplantswithseedfromwhichoilscanbeobtained.Othertriglyceridesourcesare macro-andmicro-algae.Dependingonthekindofbiomass,itsoilcancontaineither smallorhighproportionoffreefattyacids.
Intermsofitsorigin,plantbiomasscanbeclassifiedasediblebiomass(firstgeneration),non-ediblebiomass(secondgeneration),andalgalbiomass(thirdgeneration).First generationbiomassincludedavarietyofsugars,starch,andtriglyceridessourceswhich arepartofhumanfeeding.Corn,sugarcane,andsugarbeetcanbementionedamongthe first-generationsugar/starchybiomass,wherecanolaandsunfloweroilsareexamplesof triglyceridebiomass.Unfortunately,theuseofsuchmaterialsasenergysourcemayrisk thealimentarysafetyofthepopulation.Thus,somecountrieshaveestablishedpoliciesto avoidtheiruseasrawmaterialstoproducebiofuels.Toexemplify,theuseofcornto producebiofuelsispossibleinMexicoonlyonasurplusscenario(DiarioOficialdela Federacio ´ n,2008).Thus,second-generationbiomassarisesasanalternativetoavoid theuseofediblesources.Agriculturalresiduesareanexampleofsecond-generationbiomass.Suchresidueshavehighavailability,containingcelluloseandhemicellulose,which canbeprocessedtoobtainfermentablesugars.Nevertheless,theyalsocontainlignin,thus
Fig.1.5 Classificationofplantbiomassintermsofitschemicalcomposition.
pre-treatmentsarenecessarytoaccesstothedesiredcomponents.Amongthenon-edible triglyceridesources, Jatrophacurcas andcastorseedsareincluded.Suchspeciesareparticularlyresistant,sotheycanbefoundinregionswhereothercropshavedifficultiesto grow.Finally,micro-andmacroalgaeareconsideredasthirdgenerationbiomasses, andcanbesourceofeithertriglyceride-basedoilsorsugar-containingbiomass.Aninterestingcharacteristicofsuchmaterialsisthattheydonotmakeuseofcultivationland, sincetheygrowinponds.Ontheotherhand,theyrequirehighquantitiesofwater togrow,butithasbeenreportedthattheycanbegrowninwastewater,actingasabiologicaltreatmentforsuchwaters(Wollmannetal.,2019).Classificationofbiomassis depictedin Fig.1.5.Examplesofeachkindofbiomassarepresented.
Biomassisdistributedworldwide.Accordingto WorldBioenergyAssociation (2020),fromthetotaldomesticsupplyofbiomassin2017,27.7%correspondstoAfrica, 19.4%toAmerica,38.8%toAsia,13.5%toEurope,and0.6%toOceania. Table1.3 showsthereportedworldwideavailabilityofdifferentbiomasses.Sugarcanehasthehighestavailabilityintheworld;nevertheless,itisimportanttoobservethatthereportedtons arereferredtothetotalproductionofthebiomass,whichincludesthewholeplant. Moreover,cornandsugarcanearemainlyusedasfood;thus,itsuseasrawmaterials forbiofuels/bioproductsgenerationcouldnotbeappropriatefromtheethicalperspective.Ontheotherhand,thehighavailabilityofstover,straw,andbagasseisevident. Table1.3 presentstheavailabilityoffarmedseaweed.Otherbiomasssourceisgiven bymacro-andmicroalgae;nevertheless,thereisnoinformationabouttheavailability ofsuchbiomassworldwide.Theproductionofsuchbiomassisrelatedtothewater neededforitsgrowing.Somespeciescangrowinwastewater;thus,thepotentialproductioncouldbegivenbythegenerationofwastewaterineachregion.Availability ofnon-ediblevegetableoilsandanimalfatsislower,butmicro-algaecouldcontribute
Table1.3 Worldbiomassavailability.
Typeofbiomass WorldavailabilitySource
Corn 960milliontons Wolf,Dehoust,andBanse(2018)
Sugarcane 1877milliontons MakulandSua-iam(2016)
Vegetableoils(edible) a 176.23million tons Garcı´a(2016)
Vegetableoils (non-edible) b
15.7–22.4 milliontons
Chuck,McManus,Allen,andSingh (2016)
Farmedseaweed18.92million tons Chirapart,Praiboon,Ruangchuay,and Notoya(2015)
Agriculturalresidues c (stover/straw)
Agriculturalresidues d (bagasse)
1580.2million tons Tye,Lee,Abdullah,andLeh(2016)
1044.8million tons Tyeetal.(2016)
Animalfats5milliontons Chucketal.(2016)
a Includecottonseed,olive,palm,palmkernel,coconut,peanut,rapeseed,soybean,andsunfloweroils.
b Jatrophacurcas oil.Availabilityhasbeenestimatedfromtheoilproductivitydataandthereportedplantedhectares,usinga densityof0.92kg/Lfor J.curcas oil.
c Includebarley,corn,oat,rice,sorghumandwheatstraws,andcornstover.
d Sugarcanebagasse.
assourceofoils.Additionally,wastecookingoilsarealternativesourcesoftriglycerides, withanestimatedworldwideavailabilityof25milliontons(Chucketal.,2016).
Biomasscanbetransformedintoavarietyofproducts.First,theconversionofbiomassintobiofuelscanbementioned.Thetriglyceridescontainedinvegetableandalgaederivedoilscanbeconvertedintobiofuelsasbiodiesel,biojetfuel,andgreendiesel.Itis importanttomentionthatbiodieselconsistoffattyacidmethylesters,whilegreendiesel andbiojetfuelarerenewablehydrocarbonsintheboilingpointrangeoffossildieseland fossiljetfuel,respectively.Ontheotherhand,sugarandstarchybiomasshasaspotential derivativesbioalcohols,asbioethanolandbiobutanol.Moreover,suchalcoholscanbe furthertreatedtoproducebiojetfuel.Lignocellulosicbiomassisapotentialsourcefor bioalcohols,althoughitrequiredadditionalprocessingstepstoremovethelignin;this lastcomponentcanbetreatedtoobtainaromatics(Shenetal.,2015),whichcanbe blendedwithbiojetfueltoenhanceitsproperties.Suchkindofbiomasscanalsobeprocessedtoobtainrenewablehydrogen(FerreiraSoares,Confortin,Todero,DiasMayer,& Mazutti,2020).Ontheotherhand,agriculturalandpruningresiduescanbecompressed toobtainsolidbiofuels,aspellets(Mendez-Va ´ zquezetal.,2017)andbriquettes(Dinesha, Kumar,&Rosen,2019).Lignocellulosicbiomasscanadditionallybeusedtoproducea widevarietyofhigh-addedvalueproducts.Someofthederivativeswithnear-termmarketpotentialare1,4-butanediol,1,3-butadiene,ethyllactate,fattyalcohols,furfural, glycerin,isoprene,lacticacid,1,3-propanediol,propyleneglycol,succinicacid,and para-xylene(Biddy,Scarkata,&Kinchin,2016).Additionally,biopolymerscanbeeither
directlyextractedfrombiomass,ascellulose,chitin,pectin;orsynthesizedtakingbiomass asrawmaterial,asoccurswithpolyglycolicacid,polycaprolactone,polyvinylalcohol, amongothers( Jha&Kumar,2019).
Animalbiomassescanalsobeusedasrawmaterialstoobtainvaluableproducts.Feces fromsomeanimals,ascows,swine,amongothers,canbeconvertedintobiogas(Chen etal.,2010; Zhu,Zhang,Tang,Zhengkai,&Song,2011).Animalfatsarelow-costraw materialstoproducebiodiesel(Canoiraetal.,2008; Sanderetal.,2018).Insectsareother potentialrawmaterialsfortheproductionofbiodiesel,ashasbeenreportedfortheblack soldierflylarvae(Nguyenetal.,2018).
Biomassisconvertedintobiofuelsorbioproductsthroughavarietyoftreatments, eithermechanical,chemical/thermochemical,orbiological(Fig.1.6).
Mechanicaltreatmentsareusuallyemployedaspreliminarystepstoreducethesizeof theparticles,enhancingthemassandheattransferonfurthertreatments.Chemicaland biologicaltreatmentsareusedtotransformthebiomass’components.Asexamplesof chemical/thermochemicaltreatments,transesterificationandesterification,ammonia fiberexpansionpretreatment,oligomerization,andhydrotreatingcanbementioned. Amongthebiologicaltreatments,enzymatichydrolysis,andfermentationarefound. Oncethedesiredproductsareobtained,purificationmusttakeplace,sinceitisnecessary torecoverreactantsormassagentswhileisolatingtheproductsandby-products,sothey canachieveproperstandards.Purificationisnotaneasytaskforthebiomassprocessing facilities.Traditionalbiodieselproductionschemesimplyseveralwashingstepstorecover thecatalystandremovingsoaps.Ontheotherhand,fermentation-basedprocesses requireusinggreatamountsofwater;thus,thedesiredorganicproductsarehighly diluted,withahighprobabilityofoccurrenceofazeotropes.Thisimpliestheneedfor highamountsofenergyormassagentstoperformthepurificationinseveralunits,which directlyaffectstheproducingcosts.Moreover,thetransformationofbiomassintobiofuelsandbioproductsiscommonlylimitedbychemicalequilibrium,leadingtolowyields
Fig.1.6 Conversionofbiomassintobiofuelsandbioproducts.
andtheneedforexcessreactants.Allthesechallengesopenawidewindowofopportunitiestoovercomethedescribedlimitations.Atprocessinglevel,processintensification (PI)hasbeenshownasahighlyimportantstudyareaforchemicalengineers,layingthe foundationsforthedevelopmentofnoveltechnologies,moreefficient,cheaperand cleaner. Ramı´rezCoronaandPalaciosRosas(2019) summarizedthefocusofprocess intensificationonthedesignofminiaturizedunits,multifunctionalsystemsandhybrid separations,togetherwiththeintegrationofalternativeenergysources.Theapplication ofsuchphilosophyismandatoryforbiomass’conversionprocessestoallowthemtobe sustainableattheproductionlevel.PIallowsreducingequipmentsize,whichreducesthe environmentalimpactassociatedwiththeuseofresources.Loweruseoffossilfuelsfurtherreducessuchimpact.Ontheotherhand,loweringthegreenhouseemissionsassociatedtotheprocessallowreducingtheimpactsassociatedwithhumanhealth. Moreover,PIsearchesforprocesswithlowergenerationofwastes,whichhelpson reducingthedamagetoecosystems.
Unfortunately,biofuelsarenoteconomicallycompetitivewithfossilfuels.Thecost oftherawmaterialshasagreatimpactonthesellingpriceofbiofuels.Ontheotherhand, whenlow-costrawmaterialsareused,theprocessingcostincreasesduetotheneedfor furthertreatments.Topromotetheuseofbiofuels,governmentalsupportisessential. Properpolicies,assubsidiesandtaxreductions,havebeenstablishedasstrategiestopromotesuchindustry(Mansourietal.,2019);althoughspecialcaremustbetakenonthe mid-andlong-termeffectsofsuchpoliticsontheinvolvedsectors(Bi,Zeng,Zhang,& Wen,2020; Elizondo&Boyd,2017).Otherapproachtoincreasetheprofitabilityofthe biofuelsindustryisbymakinguseofavarietyofrawmaterialstoproducenotonlybiofuelsbutalsohigh-addedvalueproductsinasinglefacility.Thisisthebiorefinery approach,whichallowsobtainingavarietyofmarketablechemicals,fuels,andproducts fromeachfractionofthebiomass(EspinozaPerez,Camargo,Narva
ezRinco ´ n,&Alfaro Marchant,2017).Toexemplify,algalbiomasscanbeusedtoobtainoil,whichcanbe transformedintobiodieselorbiojetfuelandgreendiesel.Ontheotherhand,thecarbohydratescontainedinthemicroalgalbiomasscanbefermentedintobioalcohols,andthe proteinsandpigmentscanbeextractedtogenerateproductsforthepharmaceutical industry(Chewetal.,2017).Suchdiversificationofproductscouldbethemostpromissorywaytodevelopaneconomicallyfeasiblebio-basedindustry.Anadditionalaspect toensurethefeasibilityofsuchindustryistheselectionofanappropriatesupplychain. Duetothevariabilityonthelocationofbiomasses,andontheavailabilityofdifferent kindsofbiomasses,itismandatorytoproperlyselectthesourcesfortherawmaterials, thelocationofthefacilities,thebetterproductsintermsofthemarketstobesatisfied,and thelogisticsforthedistributionoftheproducts.Moreover,itisimportanttoconsiderthat biomassmaynotbeavailableinthesameproportioninthespring–summerandthe autumn-winterseasons(Espinoza-Va ´ zquez,Go ´ mez-Castro,&Ponce-Ortega,2021); indeed,thereareexpectedslightlychangesinthecompositionduetotheseasonandalso
thegeographiclocationofthecultivationsite.Theselectionofthesupplychainmust involvenotonlyeconomiccriteria,butalsoenvironmentalandsocialcriteriatoensure thesustainabilityofthewholeproductioncycle(Orjuela-Castro,Aranda-Pinilla,& Moreno-Mantilla,2019).
1.4Futuretrendsforabio-basedeconomy
Fromthediscussioninprevioussections,theconversionofbiomassintoavarietyof productsistechnicallyfeasible.Triglyceridesfrombiomasscanbetransformedintofuels asbiodiesel,biojetfuelandgreendiesel.Ontheotherhand,sugar/starchyandlignocellulosicbiomasscanbeconvertedintobioalcohols,biojetfuel,andawidevarietyofhighaddedvalueproducts.Additionally,energycanbeobtainedaspartoftheconversion schemes.Nevertheless,furthereffortsarerequiredtoensuretheeconomicfeasibility oftheconversionofbiomass.Moreover,toensureatrulysustainablebio-basedeconomy,thewholeproductionschememustbeenvironmentallyfriendlyandshowpositive effectsforthesociety.Suchproductionchainwouldthencontributetoaccomplishthe sustainabledevelopmentgoalsestablishedbytheUnitedNations(UnitedNations,n.d.).
Differentkindsofbiomasshavebeenstudiedasrawmaterialstoproducebiofuelsand bioproducts.AlthoughcountriesasBrazilandtheUnitedStateshavedevelopedbiofuels productionschemesfromrawmaterialsassugarcaneandcorn,suchapproachwouldnot beappropriateformanycountrieswheretheproductionofcropswithalimentarypurposesisnotenoughtosatisfytheirpopulation’sneeds.Thus,otherrawmaterialsmustbe preferred.Agriculturalresiduesareamongtherawmaterialswithhighestpotential,due totheirhighavailabilityandtheircontinuousgeneration.Moreover,theycanbeusedas sourceawidevarietyofproducts.Ontheotherhand,second-andthird-generationraw materialsmustbeusedastriglyceridesources.Specialattentionmustbegiventomicroalgaloil,sincemicro-algaehaveahighoilproductivityandrequirenolandforitsculture. Moreover,somespeciescangrowinwastewater,actingasabiologicaltreatmentforthose waters;thischaracteristicmustbeexploited,giventhecurrentcrisisintermsofwater availability.Additionally,theuseofwastecookingoilsasrawmaterialsforbiofuels’productionisastrategytoavoidtheinappropriatedisposalofsuchoils.
Thedevelopmentofbiorefineriesisoneofthemoreimportantstrategiestoachieve aneconomicallyfeasiblebiomass-basedindustry.Abiorefineryisthesustainableequivalentofatraditionalpetroleum-basedrefinery,whereallthefractionsofarawmaterial areusedtoobtaindiverseproducts,asfuelsandplatformmolecules.Similarly,abiorefinerymakesuseofalltheavailablefractionsofbiomass,transformingtherawmaterial intoasetofproductsthroughavarietyofoperations.Suchapproachallowsexploitingas muchaspossiblethecomponentsofbiomasstoobtainbiofuelsandvaluablebioproducts. Toexemplify,lignocellulosicbiomasscanbeusedtoproducebioalcohols.Nevertheless, theligninmustbefirstremovedtoreachthefractionofbiomasswhichcanbefurther
fermented.Thebioalcoholcanbeaproductitself,oritcanbefurthertreatedtoobtain biojetfuel.Theligninremovedinthefirststepcanbeprocessedtoobtainaromatic hydrocarbons,whichcanbeblendedwiththebiojetfueltoobtainaproductwithacompositioncomparabletofossiljetfuel.Ontheotherhand,afractionofthecelluloseand/or hemicellulosefromtheagriculturalresiduescouldbeusedtoproducemoleculesasfurfural,levulinicacid,amongothers,insteadofproducingthebioalcohol.Thisopensa widerangeofpotentialroutes,wherethebestroutemustbedecidedintermsofthekind ofbiomassavailable,thedemandoftheproducts,andthemarket’sperformance.Onthe otherhand,itwouldbedesirabletohaveflexiblebiorefineries,withthecapacitytotransformnotonlyasinglebiomass,butavarietyofbiomasses.Thiswouldhelptoavoidissues intermsoftheseasonalityofagivenbiomass.
Anadditionalstrategytoenhancetheglobalsustainabilityofthebiomass-conversion industryisrelatedwiththeenhancementoftheprocessingtechnologies.Increasingthe conversionsandyieldsobtainedonthereactionsystemswhiledecreasingtheirenergy andwaterrequirements,enhancingtheefficienciesonthepurificationsystems,and reducingtheproductionofwastes,arechallengesforthemodernprocessengineerwith thetaskofdesigningthesustainableprocessesforabiorefinery.Reducingtheenergy needsofaprocessdirectlydecreasestheenvironmentalimpactassociatedwiththeuse offuelstoproducesteam,whichisthemostusemediatoprovideheatinanindustrial process.Ifagivenequipmentrequireselectricity,thereductiononitsneedsalsodecreases theenvironmentalimpact.Sucheffectcanalsobeachievedbyusingelectricityproduced byrenewableapproaches.Toachievesuchgoals,avarietyoftoolsisavailable.Process intensification(PI)isoneofthestrategieswhichmayallowenhancingtheglobalsustainabilityoftheprocess,intermsofeconomic,environmental,andsocialindicators.PI allowsmakingabetteruseofthematerialsandenergyinsidetheprocess,promoting higheryieldsinsmallerequipment,lowerenergyrequirements,lowerwastegeneration, amongotherpositiveeffects.Ontheotherhand,energyintegrationallowsmakinguse ontheenergycontentofthestreamsinaprocesstoreducetheneedsforexternalutilities. Bythisapproach,utilities’costscanbereduced,andtheenvironmentalimpactassociated withtheproductionandsteamsandtheuseofcoolingwatercanbelowered.Nevertheless,specialcaremustbetakensincethecapitalcostscanbeincreased,duetotheneedof moreequipment.Evenso,suchincreasecouldbecompensatedwiththereductionon utilities’costs.
Thedesignofintensifiedorintegratedprocessesisnotatrivialtask.Thegeometriesof theintensifiedsystemscanbemorecomplexthanconventionalsystems.Moreover, intensifiedsystemsmayleadtoanincreaseonthenumberofdegreesoffreedom,which generatestheneedofoptimizingtheprocesstoachievethebestdesign.Intermsofenergy integration,degreesoffreedommayexistwhendevelopingtheheatexchangenetwork, oncemoreleadingtoanoptimizationproblem.Thus,thedesignofintensified/integrated biorefineriesimpliestheuseofefficientoptimizationtools,sincethemodelsrepresenting
