沼气技术

BiogastechnologyinchinaZhiyingYanStudentnumber:174Chengduinstituteofbiology,CAS1.Theconceptionofbiogaswhat’sthebiogas?Itisoriginallycalledswampgasjustbecausepeoplefounditinswamparea.Also,itisbecalledbiogasduetoproductionofthisgasbybiologicalmetabolismunderanaerobicconditions.2.Thefermentationofbiogasandits’composingBiogasfermentation,widelydistributedinthenature,isthebioconversionprocessbywhichorganicmatterisdegradedandconvertedintoinflammablegasbymanykindsofmicrobesatanaerobicconditions.Fermentationmaterialsisveryavailablesuchashumanorlivestock’smanure,straw,wastewaterandwasteresidualsfromfactories.Its’maincomposingismethane(CH4),whichcontentis55-70%.Then,itiscarbondioxide(CO2),whichcontentis30-45%.Thereisstillalittlenitrogengas(N2),hydrogengas(H2),sulfuratedhydrogen(H2S),andsoon.Sobiogastechnologycannotonlytreatorganicwastesbutalsogetakindofcleanandrenewenergy.3.MainbiogastechnologiesinChina3.1Householdbiogastechnology“Onedigesterandthreetransformations”modes“Fourinone”modes“Pig-biogas-fruit”modes“Fivetransformations”modesHouseholdbiogastechnology(1)TypicalhydraulicpressuredigesterinChinaFigure1DiagramschemeofhydraulicpressuredigesterThedigesterisasshowninthefollowingFigure1.Beforebiogasgeneration,theliquidleveloffermentationchamberisflushwiththoseofinletpipeandhydraulicchamber.Withthegradualincreaseofbiogasinfermentationchamber,thegaspressureincreasesandpushfermentationchamberliquidtohydraulicpressurechambertillinnerbiogaspressureandouterhydraulicpressuresareinbalance.Withtheconsumptionofbiogas,thebiogaspressuredecreasesandthehydraulicchamberliquidflowsbacktothefermentationchambertoreachanewbalance.Storageanddischargeofgasareperformedbycontinualchangesintheliquidlevelofthepool.