Presentation on theme: "Gas out Biomas in Biomas out (Digestate) Biogas production."— Presentation transcript:
1 Gas outBiomas inBiomas out (Digestate)Biogas production
2 Where are we. Why do we want. How do we manage. What do we need Where are we? Why do we want? How do we manage? What do we need? From where should we start? What do we want to know?
3 Biogas knowledge piramide Optimizing operational condition& designing biogas systemMethane productivity& potential, reaction, inhibition operational condition, digetibilityIdentification of biogas field in generalObtaining technical ability to obtain datato support project
4 Biogas plant concept Pig slurry Biomas out (Digestate) Fe Additional income for the farmersClean energy (kitchen)Digestate is an excellent fertilizerLess odourSanitaion
5 The microbiology process Biomasse:Animal manureOrganic wasteHydrolysisDissolved substrateAcidogenesisH2+CO2AcetognesisVFA>C2CH4+H2O+ CO2CH3-COOHMethanogenesis
6 Methane produktion Hydrolysis is process rate controlling Biomasse:Animal manureOrganic wasteHydrolysisDissolved substrateAcidogenesisH2+CO2AcetognesisVFA>C2CH4+H2O+ CO2CH3-COOHMethanogenesisHydrolysis is process rate controllingVFA transformation reduced due to:High NH3Sudden changes in environmentHigh H2 concentrationFeedback:High VFA conc. reduces hydrolysisCellulose består af glucose (C6 kulstof)Hemicellulose består af xylose og andre kulhydrater mannose, arabnose etc.Hydrolyse ved glycosidase, xylanaseLipaserProteaser
7 Physical process Lysis Non enzymatic decay Phase separation COMPOSITE MATERIALMACROMOLECULESPhysical process: DisintegrationLysisNon enzymatic decayPhase separationPhysical breakdown (shearing)
8 Biological and chemical process MACROMOLECULESSIMPLE SUBSTRATESHydrolysis (chemical)A→B1+B2 (H2O is used)Hydrolytic enzymes (biological/chemical)Made by micro-organisms – same outcome
9 Acidogenesis: (biological) SIMPLE SUBSTRATESVOLATILE FATTY ACIDSACETATE & HYDROGENAcidogenesis: (biological)Volatile fatty acids are generated from monosaccarides, fat and aminoacids.(sugar-degraders & aminoacid-degraders)Acetogenesis: (biological)Acetate is generated from LCFAs. (lcfa-degraders) and from sugar (sugar-degraders)
16 Ammonia inhibitionIn literature ammonia inhibition has been assessed relating biogas production toReactive ammonium (NH3)Total NitrogenAmmoniumHow is NH3 related to NH4+How would you recommend that the inhibition is expressed (reactive ammonium, total nitrogen or ammonium
18 VFA inhibitionInhibition at a ratio of propionic acid to acetic acid at 1.4:1Inhibition at 2 g VFA Ltr-1
19 Temperature Bacteria adaptation Batstone et al. 2002
20 Acidogenesis: (biological) SIMPLE SUBSTRATESVOLATILE FATTY ACIDSACETATE & HYDROGENAcidogenesis: (biological)Volatile fatty acids are generated from monosaccarides and aminoacids.(sugar-degraders & aminoacid-degraders)Acetogenesis: (biological)Acetate is generated from LCFAs. (lcfa-degraders) and from sugar (sugar-degraders)What happens if the temperature suddenly drops?
21 Metane production as affected by NH4+ koncentration interacting with temperature Bemærk ammoniak inhibering øges ved stigende temperatur20 days retention time in CSTR digester
22 Biogas knowledge piramide Digestibilty Optimizing operational condition& designing biogas systemMethane productivity& potential, reaction, inhibition operational condition, digestibilityIdentification of biogas field in generalObtaining technical ability to obtain datato support project
23 Definitioner VS (Volatile solids): Methane productivity: The fraction of dry matter (DM) in slurry that is transformed to gas at high temperature/incineration (550oC) for one hourHow would you measure VS?Methane productivity:CH4 production pr. unit VSCH4 production pr. unit COD35.9 MJ energy can be produced pr. m3 CH4 or 45 MJ kg CH4.En kubikmeter gylle fra kvæg og svin er MJ energi (hvilket omtrent svarer til energien i liter benzin)
24 Source of energy in animal slurry Mentioned to make clear that this presentation is about animal manure management and about the two green house gases methane and nitroux oxide.The slide is also presenting the content of the presentation.
26 Characterisation of biogas potential In the biological process the maximum biogas production BMP(liter CH4 kg(VS)-1)Volume of methane produced when residence time is in principle very longBiomasBatchudrådning af gylleBemærkhældning af kurven de første 10 dageden samlede metan produktion (Bo ultimativ biogas produktion)InoculumBMP is estimated in batch fermentation at 35oCFermentation time days
27 Anaerobic Digestibility The theoretical biogas production can be calculated from knowing the chemical composition of the biomass:TBMPIn the biological process the maximum biogas production: BMPAnaerobic digestibility =BMP/TBMPQuestion- BMP/TBMP ↑ digestibility??- BMP/TBMP ↓ digestibility ??
28 Biodegradability (BMP/TBMP) examples Here we presented BMP, TBMP and BMP per TBMP which we call biodegradability. First BMP were around 200 to 400 and TBMP were around 450 to 530 liter per kg vs ). Here you can see the biodegradability as percentage, For som animal manure and crops, the biodegradability were quite high which were around 80 to 90 percentage, but we also can see that some animal manure have quite low digestibility.
29 Lignocellulose Low digestibility lignin : Non degradable in anaerobic environmentshydrolysis of cellulose blocked by lignin.Ligninglue to hold lignocellulosic matrixprotective coatused to assess digestibility of feed in animal science
30 Lignocellulose in VS (volatile solid) The figure shows the lignocellulose fractions in VS. For most animal manure samples, the lignocellulose content were around % of VS except piglet which has quite low lignocellulose, that seems because piglet has milk as daily diet. It is interesting to see the lignocelluloses in Calf manure which are quite high because calf manure contains large amount of straw as bedding materials. That’s why the characteristics of calf manure were close to energy crop rather than animal manure. For the energy crop lignocellulose were around 60 to 80 percentage.
31 Fermentation result - animal manure The figure shows fermentation results to determine BMP. As you can see it, for the first two weeks the great majority of methane gas were produced. And thereafter only small amounts were released. We can also clearly see that there is some relation between lignin concentration and cumulative methane yield which is BMP.From this figure, we could also realized that BMP test require such a large amount of work in long period.
33 Energy potential of biomass Dry matterVolatile solids in pct of dry matter (DM)Total energy contentEnergy production in biogas plant%MJ/ kg DMMJ/kg DMPig slurry68016,39,8Cattle slurry1015,37,6Clover grass209018,314,6Straw19,19,6Why is biogas energy production of straw so low
35 Biogas production estimates With the Hashimoto equation one can assess production of biogas as affected by:temperature,hydraulic retention time,micro-organism activitybiomass composition
36 Hashimoto equation HRT or θ Hydraulic retention time SRT Solid retention timeΓIs the specific gas yieldB0The ultimate or specific methane yield, measured with batch fermentation at more than 60 days and at 35oC.maximal specific growth rate of the micro organisms, µm a function of temperature and residues feed to the reactorKis a kinetic parameter depending of the rate of feed, feed composition and bacterial consortium,S0Concentration of organic components in feed to the reactorNm3The volume CH4 produced, calculated at 0oC (273oK)
38 SummarisingBiogas is efficient in producing energy from biomasses with a high water contentBiogas transform the biomas reducing VS and thus reduced GHG emission potential of the slurryBiogas transform biomas organic N into ammonium that is an efficient fertilizer
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