英文文獻(xiàn)：HouseholdbiogasuseinruralChina:Astudyofopportunitiesand

constraintsYuChena,c,GaiheYangb,c,*,SandraSweeneya,YongzhongFengb,cABSTRACT：Asarenewableenergy,biogasisnotonlyanimportantpartofthedevelopmentofruralnewenergy,butalsoanimportantaspectofsustainabledevelopmentinChina.Thedevelopmentprocessandpresentstatusofhouseholdbiogas,specificallytheopportunitiesandconstraintsofhouseholdbiogasinruralChina,arediscussedinthispaper.Onlyabout19%ofthebiogaspotentialhasbeenutilizedinruralChina.ThereareseveralopportunitiesforhouseholdbiogasdevelopmentinruralChina,includingtheproblemofruralhouseholdenergyconsumption,theavailabilityofbiogasfermentationmaterials,nationalfinancialsubsidies,legalandinternationalcleandevelopmentmechanisms.Also,moreresearchneedstobedoneinstrawfermentationandcoldfermentationtechnology.Trainingshouldbeconductedtoraisethelevelofbiogascustomersincomprehensivebiogasutilization.Measuresshouldbetakentoimprovethefollow?upservicesandmanagementofbiogasplants.TheinformationpresentedinthispaperwillbehelpfulnotonlytothesustainabledevelopmentofhouseholdbiogasinruralChina,butalsotothedevelopmentofbiogasinsimilarcountriesaroundtheworld.1.IntroductionThedevelopmentandutilizationofrenewableenergyresourceshasbecominganimportantcomponentofasustainableglobalenergystrategy[1].In2006,about18%ofglobalfinalenergyconsumptioncamefromrenewables,with13%comingfromtraditionalbiomass[2].Chinahasalonghistoryofrenewableenergiesuseincludingbiomass,solar,geothermal,oceanandwindenergy[1].Theseresourcesrepresentmassiveenergypotential,whichgreatlyexceedsthatoffossilfuelresources[3].Biogasisdistinctfromtheotherrenewableenergiesontwofronts:one,itisacomparativelycleanhighmethanefuel,andtwo,itisimportantinthecollectionoforganicwastematerialfromwhichbothfertilizer(s)andwaterforagricultureusescanbeproduced[4].Asthestrategyapplyingofbuildingnewsocialismruralandsustainableagriculturein21century,Thedevelopmentofruralhouseholdbiogasisanimportantwaytopromoteagriculturalstructuraladjustment,increaseruralincomes,enhancetheecologyofruralareas,andimprovethequalityofbothrurallifeandagriculturalproducts[5].ThenumberofhouseholdbiogasplantsinruralChinaisthehighestintheworld[6].By2007,therewere26.5millionbiogasplants,whoseoutputhadreached10.5billionm3(equivalenttomorethan100milliontonsofstandardcoal).Householdbiogasdigestersarefoundthroughoutthecountry,mainlyintheYangtzeRiverBasin.SichuanProvincehasthelargestnumberofbiogasplants,with2.94millionrunning[7].Therapiddevelopmentofbiogasiscloselytiedtothecountry'srichexperienceindevelopingbiogas,theavailabilityoflargeamountsoffermentationmaterials,andthestrongsupportofstatefunds.However,limitingfactorsstillexist.Inthispaper,wepresentresearchonthedevelopmentprocessandpresentstatusofhouseholdbiogasinruralChina,concentratingoncurrentopportunitiesandconstrains.HouseholdbiogasuseinChinaHouseholdbiogasdevelopmentprocess

TheresearchanduseofbiogasinChinahasalonghistory,andtheuseofhydraulicdigestershasbeeninusefornearlya100years[8].Inthe1880s,thefirsttesttofermentbiogaswasundertakeninGuangdong.RectangularhydraulicdigesterswereinventedbyLuoGuoRuiin1920inTaiwan,China.AchronologyofbiogasdevelopmenteventsinChinaisshowninTable1.Table1.ChronologyofbiogasdevelopmentinChina.Year Biogasrelatedactivity1880s ThefirsttesttofermentbiogastookplaceinGuangdongCloseof19thcenturyThesimplebiogasdigesterappeared1920 RectangularhydraulicdigesterswereinventedbyLuoGuoRuiinTaiwan,China1929 FirstChineseinstitutionstopromotebiogasestablished1931 Biogaswaspopularizedthroughoutthecountryforthefirsttime1933 Thetrainingofbiogastechnologywasbegun1958 Biogaswaspopularizedthroughoutthecountryforthesecondtime;biogasresearchinstitutesestablished1970s Biogaswaspopularizedthroughoutthecountryforthethirdtime2000 TheMinistryofAgricultureproposedthe“BiologicallyEnrichmentoftheCountrysideProject”2003 TheMinistryofAgricultureproposedthe“RuralHouseholdBiogasStateDebtProject”2007 TheMinistryofAgricultureproposedthe“ProjectofRuralBiogasProject”Thelarge-scaledevelopmentofhouseholdbiogasinChinabeganinthe1970s[9].Fig.1showsthenumberofbiogasdigestersinstalledbetween1973and2005inChina[10].From1973to1983developmentfluctuatesdramatically;from1984to1994anadjustmentperiodfollowscharacterizedbyslowdevelopment;from1995to2000thepaceofdevelopmentsteadilyincreasedannually;andbythe21st,theconstructionofhouseholdbiogasdigestershadenteredanew,sustainedandrapidstage.23W兀19Nl闘F1085 1>?88 123W兀19Nl闘F1085 1>?88 1191 ]冋！L957 20(W 2007 2006-Y&arFig.1.NumberofbiogasplantsinstalledinChina[modifiedafter11].2.2.HouseholdbiogasdigesterdesignoooooflooBEJ^4n-lLuoGuoRui?typebiogasdigestersweresetupin1920s[8].Thishydraulicbiogasdigester,constructedofclay,brick,andconcrete,waswidelyusedinruralareasinthe1970s[7].ByChinesenationalstandards,thisbiogasdigesterwasconstructedin6,8and10m3volumes,andnotedintheworldfor‘‘China'smodelofbiogasdigester''[11].In2000,commercialhouseholdbiogasdigestersmadeofglassfiberreinforcedplastics(GRP)enteredthemarket[12].TheGRPdigesterhasathicknessof6-8mm,atensilestrengthof93.5MPa,andabendingstrengthof109MPa.Thevolumerangeisfrom6to10m3[13].AcomparisonofthekeytechnicalindicesbetweentheconcretedigesterandtheGRPdigesterisshowninTable2[13].FromTable2wecanseethatGRPdigesterhasalowercoefficientthermalconductivity,alongeroperationallife,lowermaintenancecosts,andashorterconstructioncyclethantheconcreteone.Table2.ThecompareofthekeytechnicalindexesbetweenconcretedigesterandGRPdigester.ThestyleTheThermal VolumOperationConstructionPriceWeighMaterialsMaintenanceofbiogasthick-conductivitye(m3)life(a)cycle(d)(Yuant(kg)digesternessof(kJ/min))thewall(cm)Concrete105.44820101800200x4clay,2?3aneeddigester0brick,a smallconcretemain?tenance4?5aneedabigmaintenanceGRP8?101.42820?300.51700200glassNoneedtodigesterfibermaintenancereinforcedplastics2.3.Householdbiogaseco-agriculturalmodels‘‘ThreeinOne''eco-agriculturalmodelThe‘‘ThreeinOne''eco-agriculturalmodel,whichcombinesthebiogasdigesterwithapigpenandtoilet,ispopularinsouthernChina[14].Themainpurposeofthismodelissimultaneouslytosolvetheruralenergycrisisandtoimprovehouseholdhygieneintheruralenvironment.Biogascanbeusedasfuelforlightingandcooking,asafertilizerforgrowingfruittrees,vegetablesandgrain,andasapestcontrolagent[11].Greenfoodcanbedevelopedfromthepattern.Byconnectingthetoilettothebiogasplantthespreadofdiseasecausedbymosquitobreedingcanbeeliminated.Tosomeextent,italsopreventstheoccurrenceofinfectiousdiseasesandthecontaminationofdrinkingwaterbyhumanandanimalfecalmatter.The‘‘ThreeinOne''eco-agriculturalmodelconstructionrequireslesscapitalinputandisquicklyeffective,whichhasbothstrenghtenedutilityandextendedvalueinthepooreconomicconditionsofthearea[14].‘‘FourinOne''eco-agriculturalmodelThe‘‘FourinOne''eco-agriculturalmodel,whichcombinesthebiogasdigester,pigpen,solargreenhouse,andtoilet,hasbeenproposedfornorthernChina[15].Thegreenhouseinthismodelcanbeusedtoincreasethetemperatureofthebiogasdigesterincreasingtheefficiencyofcoldweatherbiogasproduction.Biogascanbeusedtoincreasethetemperatureofgreenhouses.Withthetemperatureofgreenhousesincreased,vegetablescangrowwellandpigsarewell-fed[16].Usedasasprayforvegetables,theslurryinhibitsdiseaseandboostsyields[17].BecausesolargreenhouseconstructionrequiresalargerinputofcapitalandthegrowthofgreenhousevegetablesmorewaterthismodelissuitableforregionaldevelopmentintheNorthwheresolarenergyisabundant,bettereconomicconditionsprevail,andwaterresourcesareavailable[18].2.3.3.‘‘FiveinOne''eco-agriculturalorchardmodelThe‘‘FiveinOne''eco-agriculturalorchardmodel,whichcombinesthebiogasdigesterwithsolar-poweredbarns,watersavingirrigationsystem,watercellar,andtoiletisproposedfornorthwestChina[19].Biogasfertilizerisusedtogrowfruittreestoimprovethequalityofthefruit[20].Waterresourcescollectedinawatercellarareusedinthebiogasfermentation,orchardsprayingandirrigation.Theintroductionofwater-savingdevices,greatlyeasethepressureonwaterresourcesespeciallythosecreatedbythedemandsoforchardirrigationmakingthismodelissuitableforregionaldevelopmentintheNorthwestwhereseverewatershortagesexist[21].OpportunitiesforhouseholdbiogasuseinChinaIn2007,60%ofChina'spopulationor0.9billionpeoplelivedinruralareaChina.Thepercapitaconsumptionofstandardcoalis960kg,ofwhich539kgor56%isusedfordailylife,fromwhichstrawaccountedfor32.8%,fuelwood21.2%,coal34.3%,andbiogasamere1.5%[7].AccordingtoChina'sruralbiogasplanningproject(2006—2010),by2010,0.139billionruralhouseholdsaresuitableforbiogasconstruction.However,onlyabout2.65millionhouseholdsarepresentlyusingbiogasmeaningthatonlyabout19%ofthebiogaspotentialofruralChinahasbeenachieved[22].TheproblemofruralhouseholdenergyconsumptionOverthelong-term,ruralhouseholdenergyconsumptioninChinahasmainlydependedontraditionalbiomassenergy,suchasstrawandfirewood[23].Atpresent,strawstillaccountedfor32.8%,fuelwoodaccountedfor21.2%andcoalaccountedfor34.3%ofthetotalconsumption[7].Thethreeenergysourcesweremainlyusedforcookingandhouseheating,whichleadstolow-energyefficiencyandseriousenvironmentaldegradation.Forcooking,thethermalefficiencyofstrawandfirewoodisabout20%,andofcoalis30%,butthatofstrawandfirewoodisonlyabout10%iftheyareburnedintraditionalstoves[24].Today,mankindfacestwomajorglobalclimateproblems:globalwarmingwhichismainlycausedbyemissionsofCO2,andacidrain,causedbyemissionsofSOxaswellasNOx.ThedirectburingofstrawandfirewoodleadstolargeemissionsofCOandothertoxicgases.CoalcombustionisnotonlyanimportantsourceofCO2emissions,butalsothemainsourceofincreasesinSO2emissions[25].Apartfromthat,coalisalsofacingthedangerofexhaustion.Facedwiththeseproblem,wemustenhancetheefficiencyoftheconventionalenergyandincreasetheproportionofrenewableenergysourcesinthetotalenergybudget.OpportunitiesforrenewableenergypolicyFinancialsubsidyBythe21stcentury,theChinesegovernmenthadbeguntofocusonsupportingruralbiogasprojects.In2003,theCentralTreasurydecidedtoimplementtheruralbiogasprojects.Theprogramswillhaveinvested61billionRMBfrom2003to2010,ofwhich15billionRMBisfromtheNationalInvestmentFund[26].In2003,theMinistryofAgricultureDevelopmentandReformCommissionstartedtheProjectofRuralHouseholdBiogasStateDebtandinvested840millionRMBfortheconstructionofhouseholdbiogasin22provinces(autonomousregionsandmunicipalities).In2004,themovementcontinuedtoprovide1billionRMBofnationaldebtforconstructingruralhouseholdbiogasdigesters;in2005,centralinvestmentintheconstructionofruralbiogasfundsroseto2.5billionYuan,ofwhich2billionwasslatedfortheconstructionofhouseholdbiogasdigestersand0.5billionfortheconstructionoflargeandmedium-sizedbiogasdigesters[9].AsRuralBiogasConstructionStateDebtProgramManagementMethodstipulates,centralfinancesubsidizesthe“onepoolandthreereforms”inaccordancewiththefollowingstandards:1200RMB/householdinthenorthwesternandnortheasternareas,1000RMB/householdinthesouthwesternareaand800RMB/householdinotherareas[27].LawonrenewableenergyOn28February2005,PRCLawonRenewableEnergy,bringingtheexploitationanduseofrenewableenergytothestrategicheightof“increasingenergysupply,improvingenergystructure,guaranteeingenergysafety,protectingtheenvironmentalandrealizingthesustainabledevelopmentofeconomyandsociety”[28].CleandevelopmentmechanismTotackletheproblemofglobalwarming,thecleandevelopmentmechanism(CDM)wasputforwardinKyotoProtocol.Thecleandevelopmentmechanism(CDM)isanarrangementundertheKyotoProtocolallowingindustrialisedcountrieswithagreenhousegasreductioncommitment(calledAnnexBcountries)toinvestinprojectsthatreduceemissionsindevelopingcountriesasanalternativetomoreexpensiveemissionreductionsintheirowncountries.Asaconsequence,thedevelopmentofCDMbiogastechnologyprojectsandthesaleofverifiedcarbonemissionreductions(CER)hasopenedupnewchannelsoffinanceformedium-sizedbiogasprojectinChina,includinghouseholdbiogasdigestersinruralareas,leadingtoanincreaseprojectsrateofeconomicreturn.BiogasfermentationmaterialavailabilityLivestockandpoultrymanure,mostofwhichisfromcattle,pigsandchicken,andagriculturalresiduesarethemainresourceforbiogasfermentationinruralChina.Thepotentialquantityofmanurecanbeestimatedbythenumberoflivestockandpoultryandtheannualdryexcrementproductionofonelivestockorpoultry[29].Calculatedaccordingtocurrentlivestockandpoultryproduction,thetotalphysicalquantityofdryexcrementresourcesinChinais1467milliontons,ofwhich1023milliontonscanbecollected,equivalentto107milliontonsofstandardcoal[30].Accordingtotheplanforlivestockindustrydevelopment,livestockandpoultrymanurein2010and2020willreach2.5billiontonsand4billiontons,respectively,fromwhichthecollectedamountisequivalentto120and160milliontonsofstandardcoal,again,respectively[31].Thequantityofagriculturalresiduesavailableasaresourceismainlyduetotheoutputofcrops,thecollectionofcoefficientsandconsumptionpurposes[32].ThemainapproachestostrawutilizationinChinaarepapermaking,forage,ruralenergyresource,andrecyclinginfieldandcollection(includingsomelosses),accountingfor2.1%,28%,53.6%and16.2%,respectively[33].Accordingtocurrentcropproduction,thereareabout681milliontonsofagriculturalresidueproducedannuallyinChina,ofwhich546milliontonscanbecollected.Apartfromotheruses,about290milliontonscanbeusedasanenergyresource,equivalentto145milliontonsofstandardcoal.Judgedoverthelong-term,thetotalamountofstrawwillcontinuetomaintaingrowthwithpopulationgrowth[30].After2030,400—500milliontonscanbeusedasamodernhigh-efficiencyenergyresource,equivalentto200-300milliontonsofstandardcoal.ConstraintsonhouseholdbiogasuseinChinaStrawfermentationtechnologyCellulose,hemi-cellulose,lignin,pectinandwaxarethemainorganiccomponentofstraw,whichislackingineffectivenitrogenandphosphoruscomponents,hinderingmicrobialfermentation[8].Intheprocessofstrawanaerobicmethanefermentation,theanaerobicmicrobehasaweakdegradationofdigestionabilityforlignocelluloses,leadingtoaslowhydrolyticprocessandalowdegreeofhydrolysis,whichaffectsthesubsequentacidificationandgasificationprocess.Asaresult,theanaerobicdigestionofcropresiduesisinefficientandtime-demanding,produceslessgasandresultsinpoorefficiencyofinput-output,whichkeepscropstalksfrombeingusedinlarge-scalebiogasproduction[34].Manyresearchershaveachievedsomesuccessonthepretreatmentofstrawbyphysical,chemicalandbiologicalmethodstoincreasetheutilizationofstraw[35].However,manyproblemsstillexist.First,thepretreatmentincreasesthecost;second,thechemicalpretreatmentofstrawcausessecondarypollution.Moreover,thebiologicalpretreatmentofstrawisstillintheexperimentalstagepresentingdifficultiesforlarge-scaleapplications.Therefore,findingasuitablemethodforpretreatingstrawisthefocusoffutureresearch.ColdfermentationtechnologyInruralChina,thefermentationtemperatureofhouseholdbiogasisatnormaltemperatures,generallybetween8and25°C.Theminimumtemperatureforbiogasproductionis10°C,withtherateofproductionincreasingwithincreasedtemperature[36].Winter(NovembertoMarch)conditionsinnorthernChinaareunsuitableforbiogasproductionbecausethedailymeantemperatureislowerthan10°C.Asaresult,thetimeavailableforthedigestertoproducebiogasefficientlyandrapidlyare8-9months[37].Therefore,moreresearchneedstobedonetoincreasetheefficiencyofbiogasproductionincolderregions.LowcomprehensivebiogasutilizationThetechniqueofcomprehensivebiogasutilizationreducescostsandimproveseconomicbenefits,amelioratesruralecosystems,raisesruralincomes,andcontributestosustainabledevelopment[38].Themajorityofbiogasusershavenotreceivedtechnicallytraining.Asaresult,theyareunabletocombinebiogastechnologywitheco-agriculturetechnology.Instead,biogasisusedonlyforlightingandcooking.BiogasfermentationproductshavealowlevelofuseinChina,thepotentialrateofeconomicexploitationislessthan1%,andtherateofecologicalexploitationisonly4%[39].In2005,therewere6.73millionruralhouseholdsusingmultipurposetechnologyforbiogas,accountingfor37.3%oftotalruralhouseholdusers[7].So,trainingshouldbeconductedtoraisethelevelofcomprehensivebiogasutilization.4.4?Poorfollow?upservicesandmanagementofbiogasdigestersThefollow-upservicesandmanagementofbiogasdigesters,isakeyquestionofruralenergyconstructionanddevelopment.ThedevelopmentofhouseholdbiogasinruralChinafocusesmainlyonconstructionandfailstoconsidermanagement.Thus,anumberofbiogasprojectshavebrokendawnduetoalackoffollow-upservicesandmanagement.Thisnationalphenomenonisattestedtobythe2007statistic:ofthe26.5millionbiogasdigestersinChina'sruralareas,only60%ofwhichwereoperatingnormally[12].Biogastechnologyliteratestaffareinshortsupply.Mostprovinceshaveonlysmallcounty-levelruralenergyofficeswhoseemployeesnumberbetweenthreeandseven.Staffsareunabletoadapttotherapiddevelopmentstakingplaceinthefieldofruralhouseholdbiogasdigestertechnology.Thisalsoseriouslyaffectstheefficiencyofbiogasconstructionandsustainabledevelopment[40]K.ShengandY.L.Zhang,OnsustainabledevelopmentinruralmarshgasconstructioninChina,JHuazhongAgricUniv(SocSciEd)4(2007),pp.50-52[inChinese].[40].Biogaslights,stovesandotherequipmentareallprofessionalequipment,whichisdifficulttobuyinthemarket;evenwhenavailable,farmersareunabletocorrectlyinstallthem[37].Someasurestoimprovehouseholdbiogasdigesterfollow-upandmanagementservicesneedtobetaken.ConclusionsThedevelopmentprocessandpresentstatusofhouseholdbiogas,specificallytheopportunitiesandconstraintsofhouseholdbiogasinruralChina,arediscussedinthispaper.ThereareseveralopportunitiesforhouseholdbiogasdevelopmentinruralChina,includingshortageofruralenergy,theavailabilityofbiogasfermentationmaterials,nationalfinancialsubsidies,legalandinternationalcleandevelopmentmechanisms.ConstraintsencounteredindevelopinghouseholdbiogasinruralChinaincludestrawandcoldfermentationtechnology,lowcomprehensivebiogasutilization,poorfollow-upservicesandmanagementofbiogasdigesters.Also,moreresearchneedstobedoneinstrawfermentationandcoldfermentationtechnology.Trainingshouldbeconductedtoraisethelevelofbiogascustomersinbiogascomprehensiveutilization.Measuresshouldbetaketoimprovethefollow?upservicesandmanagementofbiogasplants.中文翻譯：中國(guó)農(nóng)村家庭沼氣的利用:一項(xiàng)機(jī)會(huì)與限制并存的研究陳豫a,c,楊改河b,c,*,桑德拉斯a,馮永忠b,c摘要：作為可再生能源，沼氣不僅是一種農(nóng)村新能源的重要組成部分,也是我國(guó)農(nóng)業(yè)可持續(xù)發(fā)展的需要。本文在中國(guó)農(nóng)村家庭沼氣技術(shù)的發(fā)展過(guò)程和現(xiàn)狀，特別是對(duì)家庭沼氣帶來(lái)的機(jī)遇和約束等問題進(jìn)行了探討。沼氣在中國(guó)農(nóng)村地區(qū)，大約只有19%的潛力被利用。中國(guó)農(nóng)村，發(fā)展家庭沼氣有幾次機(jī)會(huì)，包括了農(nóng)村家庭能源消費(fèi)的材料，沼氣發(fā)酵的利用能力，國(guó)家財(cái)補(bǔ)貼，法律與國(guó)際清潔發(fā)展機(jī)制等。同樣，在稻草發(fā)酵和冷發(fā)酵技術(shù)上還需要做更多的研究。應(yīng)該通過(guò)培訓(xùn)來(lái)提高沼氣用戶的沼氣綜合利用水平。應(yīng)采取措施提高沼氣發(fā)電廠的后續(xù)服務(wù)和管理。本文給出的信息，不僅有利于中國(guó)農(nóng)村家庭生物沼氣的可持續(xù)發(fā)展,同樣有利于其他發(fā)展中國(guó)家的沼氣發(fā)展。可再生能源是發(fā)展和利用資源的重要組成部分，已成為一個(gè)全球性永續(xù)能源戰(zhàn)略［1］。在2006年，大約18%的全球性的能量來(lái)自可再生能源消耗，13%的來(lái)自傳統(tǒng)生物質(zhì)［2］。中國(guó)可再生能源的使用具有悠久的歷史，包括生物能、太陽(yáng)能、地?zé)?、海洋和風(fēng)能3］。這些資源的巨大潛能，大大超過(guò)了礦物燃料資源［3］。沼氣在2個(gè)方面有別于其他可再生能源：一、它是一種比較干凈的高甲烷燃料，二、沼氣在肥料和農(nóng)業(yè)用水所產(chǎn)的有機(jī)廢棄物手機(jī)上是很重要的［4］。作為21世紀(jì)運(yùn)用于社會(huì)主義新農(nóng)村的建設(shè)和可持續(xù)農(nóng)業(yè)發(fā)展的策略，農(nóng)村家庭沼氣是一種促進(jìn)農(nóng)業(yè)結(jié)構(gòu)調(diào)整、增加農(nóng)民收入，提高農(nóng)村生態(tài)環(huán)境，提高農(nóng)村的生活和農(nóng)業(yè)產(chǎn)品質(zhì)量的方法［5］。中國(guó)農(nóng)村家庭沼氣發(fā)電廠的數(shù)量在全世界是最高的［6］。到2007年，有2650萬(wàn)沼氣發(fā)電廠，產(chǎn)氣量已達(dá)10.5億立方米（相當(dāng)于超過(guò)100萬(wàn)噸標(biāo)準(zhǔn)煤）。家庭沼氣池遍布全國(guó)各地，主要在長(zhǎng)江流域。四川省內(nèi)擁有最多的沼氣工廠,有29萬(wàn)在運(yùn)行［7］。沼氣的快速發(fā)展與我國(guó)沼氣發(fā)展的豐富經(jīng)驗(yàn)，發(fā)酵原料的大量供應(yīng)和國(guó)家基金的大力支持是緊密相連的。然而，限制因素仍然存在。在本文中，我們將研究中國(guó)農(nóng)村家庭沼氣的發(fā)展歷程和現(xiàn)狀，并專注于眼前的機(jī)遇與制約。2.沼氣在中國(guó)家庭中的應(yīng)用2?1?家庭沼氣應(yīng)用的開發(fā)過(guò)程沼氣的研究和利用在中國(guó)有著悠久的歷史，并且液壓沼氣池的應(yīng)用將近有100年了［8］。在19世紀(jì)80年代，在廣東驚醒了第一次沼氣發(fā)酵測(cè)試。1920年，在臺(tái)灣，羅國(guó)瑞發(fā)明了矩形液壓沼氣池灣。我國(guó)沼氣發(fā)展的大事件年表，表-1。表?1,中國(guó)沼氣發(fā)展年表

年份 與沼氣相關(guān)的事件19世紀(jì)80年代在廣東第一次測(cè)試沼氣發(fā)酵19世紀(jì)末簡(jiǎn)單沼氣池的出現(xiàn)1920在中國(guó)臺(tái)灣，羅國(guó)瑞發(fā)明矩形液壓沼氣池1929中國(guó)第一個(gè)促進(jìn)沼氣機(jī)構(gòu)間建立1931沼氣第一次在全國(guó)各地推廣普及1933沼氣培訓(xùn)技術(shù)的開始1958沼氣科研院所的建立，沼氣第二次在全國(guó)各地推廣普及1970沼氣第三次在全國(guó)各地推廣普及2000農(nóng)業(yè)部提出“生物富集的農(nóng)村項(xiàng)目”2003農(nóng)業(yè)部提出“農(nóng)村家庭沼氣國(guó)家債務(wù)項(xiàng)目”2007農(nóng)業(yè)部提出“農(nóng)村沼氣工程項(xiàng)目”中國(guó)家庭沼氣于20世紀(jì)70年代開始大規(guī)模發(fā)展［9］。圖-1顯示了1973年和2005年之間中國(guó)沼氣池的安裝數(shù)量［10］。1973年到1983年大幅波動(dòng)發(fā)展；從1984年到1994年由于發(fā)展緩慢出現(xiàn)了一段調(diào)整期；自1995年到2000年以穩(wěn)定的速度增加。二^一世紀(jì)的今天，家庭沼氣池的建設(shè)進(jìn)入了一個(gè)新的，持續(xù)、快速的階段。家庭沼氣的設(shè)計(jì)羅國(guó)瑞所設(shè)計(jì)的沼氣池在20世紀(jì)20年代成立［8］。該液壓沼氣為粘土、磚、混凝土結(jié)構(gòu),20世紀(jì)70年代被廣泛應(yīng)用于農(nóng)村地區(qū)［7］。由中國(guó)國(guó)家標(biāo)準(zhǔn)，該液壓沼氣池構(gòu)建成三種模式，分別為6、8、、10m3,并被譽(yù)為“中國(guó)液壓沼氣模式,［11］。在2000年，由玻璃纖維增強(qiáng)塑料（GRP）建成的商業(yè)家庭沼氣病態(tài)進(jìn)入市場(chǎng)［12］。GRP沼氣池厚6?8mm、拉伸強(qiáng)度為93.5MPa、彎曲強(qiáng)度為109MPa。體積范圍從6到10m3［13］。表-2顯示了混凝土沼氣池和GRP沼氣池的一些關(guān)鍵技術(shù)指標(biāo)對(duì)比［13］。從表-2，我們可以看到與混凝土沼氣池相比，GRP沼氣池具有一個(gè)較低的熱傳導(dǎo)系數(shù)，較長(zhǎng)的運(yùn)行壽命，較低的維護(hù)成本和較短的建設(shè)周期圖-1，中國(guó)安裝沼氣池?cái)?shù)量表-2，混凝土沼氣池與GRP沼氣池之間關(guān)鍵技術(shù)指標(biāo)對(duì)比沼氣池池壁厚熱導(dǎo)率體積使用壽建設(shè)周造價(jià)重量材料維護(hù)風(fēng)格 （cm） （kJ/min） （m3） 命（a）期（d） （元） （kg）混凝土105.44820101800200x40粘土、磚2?3a需沼氣池塊、水泥要一次小維修，4?5a需要一次大維修GRP沼氣池8?101.42520?300.51700200玻璃纖維增強(qiáng)不需要維修塑料2.3?家庭沼氣生態(tài)農(nóng)業(yè)模式2.3.1三位一體”的生態(tài)農(nóng)業(yè)模式把沼氣池和豬圈、廁所結(jié)合在一起“三位一體”生態(tài)農(nóng)業(yè)模式，在南方比較流行［14］。該模型的主要目的是解決農(nóng)村家庭能源危機(jī)和改善農(nóng)村環(huán)境衛(wèi)生狀況。沼氣，可以用于照明和烹飪，也可以作為肥料，種植果樹、蔬菜和谷物，還可以作為殺蟲劑［11］。這種模式可以發(fā)展綠色食品。通過(guò)連接衛(wèi)生間的沼氣發(fā)電廠，可以消除引起疾病傳播的蚊子。在某種程度上，這也可以防止傳染病和人類和動(dòng)物排泄物造成的水污染?！叭灰惑w”的生態(tài)農(nóng)業(yè)模式是一種低投入高效率的模式,在經(jīng)濟(jì)貧困地區(qū)已經(jīng)有了很強(qiáng)的實(shí)用性和推廣價(jià)值［14］。2.32“四位一體“的生態(tài)農(nóng)業(yè)模式把沼氣池和豬圈、廁所、太陽(yáng)能溫室結(jié)合在一起的“四位一體”生態(tài)農(nóng)業(yè)模式，在中國(guó)北方已經(jīng)得到提出［15］。溫室可用于提高沼氣池的溫度來(lái)提高寒冷天氣沼氣的產(chǎn)率。同時(shí)沼氣有能提高溫室的溫度。隨著溫室溫度的增加，溫室蔬菜能長(zhǎng)得好，豬長(zhǎng)得更肥［16］。沼氣作為噴霧藥劑，可以抑制疾病、提高蔬菜產(chǎn)量［17］。由于日光溫室結(jié)構(gòu)需要更大的資本投入，溫室蔬菜的生長(zhǎng)需要更多的水,因此，該模型適用于太陽(yáng)能豐富，有更好的經(jīng)濟(jì)條件和水資源豐富的中國(guó)南方地區(qū)［18］。2.33“五位一體”的生態(tài)農(nóng)業(yè)果園模型把沼氣池和太陽(yáng)能谷倉(cāng)，節(jié)水灌溉系統(tǒng)，水窖、廁所結(jié)合在一起的“五位一體”生態(tài)農(nóng)業(yè)果園模式在中國(guó)西北已經(jīng)得到提出［19］。沼肥被用來(lái)種植果樹和提高水果質(zhì)量［20］。儲(chǔ)存在水窖的水資源用于沼氣發(fā)酵、果園噴灑、灌溉。節(jié)水設(shè)備的引入,大大緩解水資源壓力，特別果園灌溉水的需求壓力這種模型適用于存在嚴(yán)重缺水的西北地區(qū)發(fā)展［21］。家庭沼氣在中國(guó)應(yīng)用機(jī)遇在2007年,60%或者說(shuō)0.9億中國(guó)人居住在農(nóng)村。標(biāo)準(zhǔn)煤的人均消費(fèi)為960kg，539kg或者說(shuō)56%用于日常生活，32.8%來(lái)自秸稈燃燒，21.2%來(lái)自木柴，3403來(lái)自煤，沼氣僅占1.5%［7］。根據(jù)農(nóng)村沼氣項(xiàng)目（2006?2010），到2010年，0.139億農(nóng)戶認(rèn)為沼氣建設(shè)是合適的。然而，目前僅僅265萬(wàn)農(nóng)戶在使用沼氣，這就意味著，只有19%的沼氣在中國(guó)獲得實(shí)現(xiàn)［22］。3?1?農(nóng)村家庭能源消費(fèi)問題長(zhǎng)期以來(lái)，中國(guó)農(nóng)村家庭能源消費(fèi)主要依靠傳統(tǒng)的生物質(zhì)能源，例如秸稈和木柴［23］。當(dāng)今，在總消費(fèi)中，秸稈仍然占32.8%，木柴占21.2%，煤占34.3%［7］。這三大能源主要用于做飯和取暖，從而導(dǎo)致低能源效率和嚴(yán)重的環(huán)境退化。做飯過(guò)程中，秸稈和木柴的熱效率約為20%,煤炭為30%,如果秸稈和木柴在傳統(tǒng)爐灶燃燒的話只有約10%［24］。當(dāng)今，人們面臨兩大全球氣候問題：主要