energyequipsys/Vol2/No2/AUG2014/171-184EnergyEquipmentandSystemshttp://energyequipsys.ut.ac.irhttp://energyequipsys.comEnergyauditingincementindustry:AcasestudyMortezaGholipourKhajeha*MasoudIranmaneshaFarshidKeyniaaaEnergyDepartment,InstituteofScience,HighTechnology&Environmentalsciences,GraduateUniversityofAdvancedTechnology,Kerman,IranABSTRACTIndustrialenergyconsumptionliesbetween30%and70%ofthetotalenergyconsumedinselectedcountries.Cementproductionisoneofthemostenergyintensiveindustriesallaroundtheworld.ThispaperdealswithanenergyauditanalysisinacementplantinIran.Inallrecentworks,afterperforminganenergyaudit,differentstrategiesareofferedtoreduceenergylosses.Generally,thesestrategiesdifferfromtheviewpointofeconomicsandtheirextentoflossreduction,whichmakesitdifficulttochooseoneofthem.Inthispaper,adecision-makingproceduresuchasananalytichierarchyprocess(AHP)afteranenergyauditprocessisproposedtohelpthedecisionmakerinthisprocess.Articlehistory:Received7August2014Accepted27September2014Keywords:CementIndustry;EnergyAudit;HeatandElectricityBalance;Decision-MakingProcedure.1.IntroductionIndustrialenergyconsumptionliesbetween30%and70%oftotalenergyconsumedinselectedcountries[1-8].Anotableamountofenergyisusedinthecementindustry.Therefore,considerableattentionisneededforthereductionofenergyandenergy-relatedenvironmentalemissions,locallyorglobally[9-13].Itisreportedthatthisindustryconsumesabout15%oftotalenergyconsumptioninIran[14].Beinganenergyintensiveindustry,thissegmentofindustrytypicallyaccountsfor50–60%oftotalproductioncosts[15].Thetypicalelectricalenergyconsumptionofamoderncementplantisabout110–120kWhpertonofcement[16].Ithasbeenproventhatathermalenergysavingpotentialof0.25–0.345GJ/t,anelectricalenergysavingpotentialof20–35*Correspondingauthor:EnergyDepartment,InstituteofScience,HighTechnology&Environmentalsciences,GraduateUniversityofAdvancedTechnology,Kerman,Iran.E-mailaddress:gholipour_morteza@chmail.ir(MortezaGholipourKhajeh)kWh/tandanemissionreductionpotentialof4.6–31.66kgCO2/t[17-22]isfeasibleinthisindustry.Duetotheirwidespreaduse,efficientstrategiesforcontrollingmotorsareoftheessence.Upto700electricmotorscanbefoundinacementplantwithvariouspowerratings[23].Anumberoffunctionsareperformedbyelectricmotorsanddrivesinacementfactory,includingfanmovement,grinding,kilnrotationandmaterialtransport.Motorscanberewired(whichisoftenpreferredtoreplacement)whennecessary[23].Fujimoto[24]andHendriks[25]foundtheenergysavingtobe3–8%withhigh-efficiencymotors.Variablespeeddrives(VSD)appearinthefansofcoolers,pre-heaters,kilnsandmillsamongotheritems[26].Bettercontrolstrategiesformotordrivesarecrucialastheyconsumealargeportionofpowerinthecementindustry.Althoughmostmotorsarefixedspeedmodels,partialorvariableloadoperationiscommon,especiallyconsideringtheloadvariationsthatoftenoccurincementplants[27].172MortezaGholipourKhajehetal./energyequipsys/Vol2/No2/AUG2014Inatypicalcementindustry,energeticandexergeticanalysisofwasteheat(mainlybyfluegasesandtheambientairstreamusedforcoolingdowntheclinker,about35%to40%oftheprocess’heatloss)recoverysystemshasbeenperformedbyS.Karellasandcoworkers[28]inwhichtwodifferentcycleshavebeeninvestigated;awater-steamcycleandanOrganicRankineCycle(ORC)withisopentaneastheworkingfluid.Energyandexergyanalysisprovedthatthewatersteamcycleshowsbetterperformancewithasysteme...
