Training on Biogas and Biomethane Production

Transcription

1 Training on Biogas and Biomethane Production Biogas Production - Information for a successful biogas plant operation - Fraunhofer IWES Division Bioenergy and System Technology Biogas plant technology Gas upgrading, injection and grids Sustainability Demand oriented energy supply Hessian Biogas Research Centre (HBFZ)

2 Content Feedstock materials Digestion Biogas Energy Production Digestate 3 Biogas Production - Feedstock X X X X X 4

3 Biogas Production - Feedstock Feedstock: Organic fraction of municipal solid waste Impurities: Metal, plastics, stones Bunker Manual sorting out coarse matter (optional) Crushing Separation of metals Sieving Removing inert particles Separation of inadequate components => waste! 5 Biogas Production - Feedstock Feedstock properties: Fresh matter (FM) [kg] Water content (% of FM) [kg H2O /kg FM ] Dry matter (DM) [kg DM /kg FM ] Organic dry matter (odm) [kg odm /kg FM ] Density substrate (ρ) [kg/l] ~ 1 Specific gas yield (Y Gas ) [L Gas /kg odm, in ] Methane concentration (c CH4 ) [Vol.-%] Availability: Own premises [to odm /ha*a] Delivery contracts [to odm /a] 6

4 Biogas Production - Digestion Biological degradation of organic compounds in 4 steps: manure wastes plants Carbo hydrate Fat Protein 1 st step cracking macromolecules Sugar Carboxy acids Amino acid Bases 2 nd step digesting monomers Fatty acids Gases Alcohols 3 rd step formation of methanogenic substrates Acetic acid Hydrogen Carbon dioxide 4 th step biogas production Biogas Methane Carbon dioxide hydrolytic acidogenetic bacteria acetogenetic methanogenic bacteria Different populations with partly contradicting ambience preferences Activity hampered by own metabolites Ambient conditions in a digester are a compromise 7 Biogas Production - Digestion source: Dienstleistungen/Waerme/Biogas/Biogasanlage_Schwandorf 8

5 Biogas Production - Digestion 9 Biogas Production - Digestion BEKON Dranco Dry Fermentation: Advantageous for feedstock with low water content Parallel digesters necessary for continuous biogas flow and gas quality Batch process needs complex procedures for explosion prevention Less machinery but more staff for loading and unloading digesters Combination of dry and wet digestion makes sense source: Biogas, Top Agrar 10

6 Biogas Production - Digestion Benchmarks for biogas production: Usable volume digester (V R ) [m³] Mass flow feedstock (m ) [kg FM /d, kg odm /d] Dry matter feedstock (DM) [kg DM /kg FM ] Dry matter in digester (DM) [kg DM /kg FM ], 0,05-0,15 Organic dry matter (odm) [kg odm /kg FM ], ~ 0,05 Retention time (t r ) [d], calculation: t r = V R *ρ/m Minimum 20d! Always check both parameters!!! Volume load(l V ) [kg odm /(m³ R *d)], 1-20 calculation: L V = m *odm/v R Maxima: maize silage 3, manure 5, waste 20 kg odm /(m³ R *d) 11 Biogas Production - Biogas Biogas Composition Gas component Vol.-% Methane Carbon dioxide Nitrogen 0-7 Oxygen 0-2 Hydrogen 0-1 Hydrogen sulphide 0-1 Elemental sulphur formed by bacteria which digest H2S 12

7 Biogas Production - Biogas 13 Micro gasturbine Biogas Production - Biogas Pilot injection Diesel engine 14

8 Biogas Production - Energy Benchmarks for energy production: Biogas production (V Gas ) [m³ N /d] Calculation: V Gas = m *odm*y Gas Power, gross (P total ) [kwh/d] Calculation: P total = V Gas *c CH4 *H i,ch4 Net calorific value methane H i,ch4 10 kwh/m³ N Power, electric (P el ) [kw] Calculation : P el = P total *η el /0,9 for Diesel Electrical efficiency CHP 35-42% Power, thermal (P th ) [kw] Calculation: P th = P total *η th /0,9 for Diesel Thermal efficiency CHP 45-55% 15 Biogas Production Energy Benchmarks for energy production: Energy, electric (E el ) [kwh el /a] Calculation: E el = P el *h max -E el,aux Full load hours (h max ) [h/a] E el /P el Auxiliary power (E el,aux ) [kwh el /a] ~ 3-15% of E el Energy, thermal (E th ) [kwh th /a] Calculation: E th = P th *h max -E th,aux Full load hours (h max ) [h/a] E el /P el Auxiliary power (E th,aux ) [kwh th /a] ~ 50% of E th 16

9 Biogas Production Digestate Utilization of digestate to be done preferably in the most cost effective way spreading on agricultural land most common method Power of biogas plant [kw el ] Digester residue production [t/a] Application area [ha] Sometimes not possible to spread without any treatment because: The maximum allowable fertilizer concentration of the soil is reached Sanitation is necessary Too many heavy metals or other hazardous components 17 Biogas Production Digestate Essential objectives of digester residue treatment are: Export of nutrients Saving storage and transport costs Selling treated products (fertilizers, compost, pellets) Reduction of environmental impacts as Pathogenic activation Emission of pollutants Waste and waste water Odour 18

10 Biogas Production Digestate Digestate treatment processes Mechanical Chemical Thermal Centrifugal separation Membrane separation Pressing Precipitation with CaPO 4 Precipitation with MAP Drying Stripping ammonia Evaporation 19 Biogas Production Digestate Screw press separator [UTS Products GmbH] [UTS Products GmbH] 20

11 Biogas Production Digestate Decanter centrifuge Source: modified after HEMMING & WAGNER (2008) [Fa. Spaleck Oberflächentechnik GmbH] 21 Biogas Production Digestate Filter presses Belt filter press [Fa. Passavant Geiger GmbH] [Fa. Passavant Geiger GmbH] 22

12 Biogas Production Digestate Ultra filtration process 23 Biogas Production Digestate Solar drying with the electric mole [Fa. Thermo-System Industrie - & Trocknungstechnik GmbH] [Fa. Thermo-System Industrie - & Trocknungstechnik GmbH] 24

13 Biogas Production Digestate Drum drier [Fa. Dörfler GmbH] [Fa. Dörfler GmbH] 25 Training on Biogas and Biomethane Production Do you have any questions? Thank you for your attention. [Copyright: Schmack Biogas AG] 26

14 Training on Biogas and Biomethane Production Contact: Henning Hahn Fraunhofer IWES Division Bioenergy and System Technology Königstor Kassel, Germany 27 Training on Biogas and Biomethane Production Key figures: Manure from 3 Cows = covers the electricity demand of one priv. Household 1 kwel installed capacity = 0.5 ha maize = Manure from 8 cows 1 t FM maize = m³ Biogas 1 m³ biomethane = 1 l oil equivalent 1 m³ biomethane = kwh el Biogas plant electricity demand: 5-25 % Biogas plant heat demand: 5-25 % Necessary labour hours: 8-10 lh/kwel installed 28

15 Training on Biogas and Biomethane Production organic waste source DM odm biogas yield biogas yield methane content [%] [% of DM] [l N/kg odm] [m³/t FM] [%] old bread fats Organic waste from priv. households grease trap removal sludge (liquid) grease trap removal sludge (solid) flotate sludge potato (fruit-water - starch production) potato (process-water - starch production) potato pulp potato pulp (pressed, from starch production) potato shells potato grain cheese waste molasses rumen content rape press cake rye powder rye grain sour whey (diluted) sour whey (fresh) food waste whole milk (fresh) cabbage slices waste no data onion slices ,