新能源概论课件4en

Chapter4BiomassEnergyMainContents4.1Bioenergybasics4.2Bioenergytechnology4.3BioenergyinChina4.4Someproblemsandtechnologytrends4.1Bioenergybasics1.WhatisBiomass?solarenergyH2O+CO2Carbohydrates+O2plantBiomassreferstoavarietyoforganisms生物体resultingfromphotosynthesis光合作用.Photosynthesisistheprocessofconvertingthesolarenergytocarbohydrates（碳水化合物）andoxygenthroughusingcarbondioxideintheair.Biomassenergyisakindofenergywhichusesbiomassasthecarrierandisintheformofchemicalenergy.2.WhatisBiomassEnergyAdvantagesofBioenergy:•Clean,lessCO2andNOxemissions；•Renewableandsustainable；•Widedistribution，largeoutput，andvarioustransformation•FacingfewertechnologyproblemsthanothernewenergyDisadvantagesofbioenergy：•Lowerheatvalue,andhighwatercontentwhichcanreducethecombustionefficiency;•Dispersedistribution,hardtocollect,transportandpre-process；•Lackoflandtogrowenergyplants.3.BiomasssourcesEnergyCropsWoodycropsAgriculturalcropsWasteProductsWoodresiduesCropwastesAnimalwastesMunicipalSolidWaste(MSW)CommercialandindustrialwastesTypesofBiomassCornSoybeansSorghumSugarCaneBagasseSwitchgrass柳枝CornStover秸秆WoodChips&Sawdust木屑MunicipalSolidWaste,MSW4.2BioenergytechnologyTechnologiesConversionProcessMajorBiomassFeedstockEnergyProducedDirectCombustionThermochemicalWoodAgriculturalwasteMunicipalsolidwasteHeat,Steam,ElectricityGasificationGasPyrolysis热解Syntheticfueloil(biocrude)Anaerobic厌氧(Biogasproduction)BiochemicalAnimalmanure肥料,Agriculturalwaste,Landfills,WasteWaterMethane甲烷Aerobic有氧(EthanolProduction)SugarorstarchcropsWoodwastePulpsludge纸浆渣GrassstrawEthanol乙醇BiodieselProductionChemicalRapeseed油菜SoybeansWastevegetableoilAnimalfatBiodiesel1Bioenergytechnologyoptions•DirectCombustion2ThermochemicalprocessGasificationofbiomassistheprocessofconvertingthebiomasstogasusingoxygen,vapororhydrogenasgasficationagent.ThemainproductsareCO,H2,CH4,CO2,etc.Thegasificationprocesshasthreestages.1)drythebiomass2)decomposethebiomassintogas,tar（焦油）andcoke（焦炭）3)formtheproductionofsecondstageintohydrocarbon,hydrogenandothercombustiblesubstance.•GasificationBiomassGasifier200tonsofwoodchipsdailyConvertedtogasat~1850ºFCombinedcyclegasturbine8MWpoweroutput•Pyrolysis热解OrganicmaterialpartiallycombustedtoproducesecondaryfuelsandchemicalproductTheprocessofPyrolysisgivesthreegroupsofproducts.solid–char炭orcharcoal木炭liquid–pyroligeneousacid（焦木酸）oroilwhichcontentamixtureofchemicalsamixtureofgases–CO,H2,N2Fermentation发酵Naturallyoccurringbiochemicalprocessconcernedtomicro-organism.Micro-organismareinvisiblebacteriaoftwomajorgroups.–Aerobic(whichgrowsinthepresenceofoxygen)–Anaerobic(whichgrowinabsenceofgaseousoxygen).3BiochemicalprocessAerobicFermentation（有氧发酵）--EthanolProductionEthanolfeedstocksSugars,fromsugarcane,sorghumStarch（淀粉）,fromgrains(rice,maizeetc.)cassava（木薯）,potatoCellulose（纤维素）,fromwoodagriculturalresidues.AnaerobicDigestion（厌氧发酵）-DecomposebiomasswithmicroorganismsClosedtanksknownasanaerobicdigesters（沼气池）Producesmethane甲烷(naturalgas)andCO2Methane-richbiogas（沼气）canbeusedasfuelUsedinanimalfeedlots饲养场,andelsewhereUsenaturalplantoilssuchassoybean,corn,palm,andcanola油菜籽oilsTransesterification酯交换反应ofvegetableoiloranimalfatproducesfattyacidmethylester脂肪酸甲酯Producebiodiesel4ChemicalprocessBiodieselBus5BiomasspowergenerationDirectCombustionBurnbiomasstocreatesteamCo-FiringMixbiomasswithcoalincoalplantsEconomicallyattractiveGasificationPyrolysisAnaerobicDigestionBiomasspowergenerationtechnologyMunicipalSolidWastePowerPlant4.3BioenergyinChina我国每年废弃的农作物秸秆约1亿吨，折合标准煤5000万吨。预计2020年全国每年秸秆废弃量将达2亿吨以上，折合标准煤1亿吨，生物质发电资源利用潜力巨大。1生物质发电方面2003年以来，国家先后核准了河北晋州、山东单县和江苏如东3个秸秆发电示范项目，并实施了优惠上网电价等政策，使生物质发电特别是秸秆发电迅速发展。《可再生能源中长期发展规划》提出了2020年生物质发电装机3000万千瓦的发展目标。但近十年来，生物质发电项目普遍亏损，主要原因有•我国利用农林废弃物规模化发电技术尚不成熟；•单位造价高，每千瓦造价9000-10000元；•燃耗较高，燃料成本高，单位燃料成本0.4元左右，上网电价须达到0.7-0.8元/kWh；•相关政策和措施不配套，标准和规范不完善；•区域投资过热、近距离扎堆重复建设，布局不合理；•秸秆市场抢购造成燃料价格上涨和秸秆收购量不足。2010年7月23日，国家发改委发布《关于完善农林生物质发电价格政策的通知》，将全国农林生物质发电执行的上网电价，统一定为每千瓦时0.75元（含税）。可使全国大部分生物质能电厂实现盈利。2010年8月10日，国家发改委《关于生物质发电项目建设管理的通知》(1803号文)对影响生物质发电产业发展的重复建设、争夺燃料等问题，也在政策上作出了规定。如每个县或者100公里半径范围内不得重复布置生物质发电厂；生物质电站建设规模一般安装2台机组，装机容量应与资源量匹配，考虑到生物质燃料的运输半径，一般不超过3万千瓦；要求把生物质发电规划制定、生物质资源落实作为项目核准的重要条件。Source:LiuBaoliang,ThestatusofbiomassgasificationforpowerinChina,20102生物质燃料方面StatusinChinaInthenearfutureMidtolongtermdirectionStartedMainlyfromcornMarginallandfortheproductionofcassava,sweetsorghumPromotethedevelopmentoffuelethanolfromcelluloseBio-ethanolCaseStudy:BiogasinLijiang,Yunnan4.4SomeproblemsandtechnologytrendsTheproblemofrawmaterialAgricultureresiduearedispersedandthedensityofenergyislow,socollection,transportationandpretreatmentareneededtosettle.TheproblemofpowerefficiencyTheproblemofcapitalandpolicyTheproblemofsecondpollutionAshandwastewaterpollutionarekeyproblems.Theashcanberemovedbyincreasingtheefficiencyofgasification.Itishardtotacklewastewater.1SomeproblemsRoadMapforBiomassBio-Conversion,USDemonstrationPilotscaleIndustrializationExplorationNearlyzeroemissionLargescaleapplicationLargescalehigh-gradecleanfuelapplicationPretreatme