Estudo computacional da calibração e substituição do gás natural veicular por biometano em um motor de ignição por centelha e seu impacto no setor de mobilidade urbana brasileiro

Abstract

The intensificationofclimatechangeandthedeteriorationofairqualitydemand sustainable energysolutionsthatreconcilevehicularmobilitywiththemitigationofgreen- house gas(GHG)emissions.Amongthealternatives,biomethaneemergesasaviable substitute forcompressednaturalgas(CNG),duetothesimilarityoftheirphysicochemical propertiesanditspotentialtoreduceGHGemissionswithoutrequiringstructuralchanges to therefuelinginfrastructure.Inthiswork,throughnumericalsimulationsusingthe GT-SUITE® software,thecalibrationofaspark-ignitionenginecommerciallyemployedin light-dutyvehiclesoriginallydesignedforCNGwasdeveloped.Thestudyconsideredboth the directfuelsubstitutionandtheoptimizedignitiontimingcalibrationtomaximize performanceandminimizeGHGemissions.Suchmodificationsaredeemedfeasiblesince they donotrequirephysicalchangestotheengine,butratheranadjustmentoftheengine map intheelectroniccontrolunit.Inthedirectsubstitutioncase,withoutcalibration adjustments,nosignificantlossesintorqueandpowerwereobserved,withrecorded reductions ofupto1.94%in CO2, 4.03%in CO, and2.26%in NOx. Withignition timing calibration,retardedby1° to 3° compared toCNG,performanceimprovements wereachieved,withgainsinpowerandthermalefficiency,inadditiontofurtheremission reductions, reaching2.30%for CO2, 4.48%for CO, and1.64%for NOx. Whenassessing the substitutionofCNGbybiomethane,basedontheGHGemissiondataobtainedfrom numericalsimulations,theBrazilianvehiclefleet,andtheestimatedfuelconsumption and mileageofCNG-poweredvehiclesinBrazil,itwasobservedthatthereplacement of CNGbybiomethaneinthenationalfleetcouldmitigateupto79.51thousandtons of CO2 and 18.12thousandtonsof NOx peryear.Theenergydemandassociatedwith the purificationprocesswasalsoevaluated,highlightingthattechnicalfeasibilitymustbe accompanied bypublicpoliciesandspecificlegislationtofosterbiomethaneproduction and vehicularuse.Theresultsdemonstratethatbiomethane,particularlywithproper calibration, isacompetitiveandenvironmentallyadvantageousalternativecompared to CNG,contributingtothedecarbonizationofthetransportationsectorandtothe valorizationoforganicwasteinBrazil.Theimplementationofthistechnology,coupled with regulatoryincentivemechanisms,mayincreasetheshareofrenewablefuelsinthe energy matrixandsignificantlyreduceairpollution.