Large Biogas Plants in Denmark -technology and operation experience

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1 Large Biogas Plants in Denmark -technology and operation experience September by Anne Seth Madsen, [email protected] 1 NIRAS

2 Agenda NIRAS Large Biogas Plants in Denmark Large Biogas Plants concept and tour Input materials and gas production Economy 2 NIRAS

3 NIRAS Background Multi disciplinary Consultancy Since Employees, 2/3 hold academic degrees Turnover 49 million Euro (2002/2003) Odense Svendborg 3 NIRAS

4 Biogas Experience in NIRAS Biogas Consultancy for 20 years Total 8 joint plants built in DK International activities Danish operations, upgrading and planning consultancy R&D Activities - Digestion of Grass - Restaurant waste - Odor control - Process control - Reject water handling - Pre-treatment 4 NIRAS

5 Biogas Concept Anaerobic treatment = Biogas production 5 NIRAS

6 History of Biogas in DK 6 NIRAS

7 Biogas Plants in operation m 3 biomass processed at: Large plants 2002 Animal manure Organic waste Total Farm Plants New projects app. 15! 20 Large Biogas Plants! 57 Farm based Biogas Plants 7 NIRAS

8 Snertinge Biogas Plant 8 NIRAS

9 Waste Collection Tankers 20 m 3 30 m 3 Tippers Pipeline Average distance to plant Emptying cycle 9 NIRAS

10 Pre-Treatment: Hygienisation / sterilization Hygienic step if recycling nutrients Separate unit to guarantee of retention time Elimination of pathogens and weeds 10 NIRAS

11 Digesters Steel or concrete tanks Insulated Processes mesophilic thermophilic 11 NIRAS

12 After Storage Second digester Buffer for return of digestate or Buffer before aftertreatment 12 NIRAS

13 After treatment: e.g. separation Separation in solid and liquid fraction Different technologies Centrifuge Solid fraction 12% Liquid fraction 88% 13 NIRAS

14 3.4.4 Solids Fraction Will contain most phosphorours Dry matter content up to 30% 14 NIRAS

15 Fluid fraction - post treatment Various technologies can separate the liquid fraction in Concentrated nutrients Reject water 15 NIRAS

16 3.2.9 Gas Storage Equalize gas production Max for 24 hours storage Size depends on utilization of gas 16 NIRAS

17 3.4.1 Gas Treatment Gas contains H 2 S Can be removed biologically in after storage gas cleaning unit 17 NIRAS

18 3.4.2 Gas Utilization Boilers Internal Combustion Engines Gas turbines CHP applications Fuel Cells 18 NIRAS

19 Input material Pre-conditions Gas potential (CH 4 = methan) Dry matter in manure Example of input from 7 plants 19 NIRAS

20 Pre-conditions In principal all organic wastes that are: Free of substances that inhibit the biogas process Suitable DM content Free of environmental toxic substances Sufficient biogas production 20 NIRAS

21 CH 4 production and DM% Pig slurry 25 Gas production for various DM contents in pig manure 20 m3 CH4 / m3 input ,0% 4,0% 5,0% 6,0% 7,0% 8,0% 9,0% 21 NIRAS

22 Remenatns from flavouring Soy oil Kitchen and canteen waste CH 4 production capacity m3 CH4 / m3 input Sudge from edible fats Victuals old Protein Household waste Sewage sludge conc. Sewage sludge Bleach clay Fish waste Flotation sludge Stomac content pig Pig manure Pig slurry Cow slurry 22 NIRAS

23 Operational journal 23 NIRAS

24 Input composition 2001 Input composistion in Danish biogas plants % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% VEG SIN FAN LEM HOD HAS THO Other industrial waste Conc. Fat waset (>60%) Medicinalind.other Medicinalind., mucosa Tannery waste Oil mill, bleach soil Pektinin sludge Daiary waste Backery waste Fish waste flotation sludge Residues fodder production Fat/floataion sludge Stomach content - slaughter house Other manure Pig manure Cow manure 24 NIRAS

25 Economy: Income Gate fees Gate fees for organic waste Biogas Electricity sale Heat sale? Fertiliser 25 NIRAS

26 Economy: Capital cost Capital cost, plant mio m3/year 26 NIRAS

27 Economy: Running cost Running cost EURO 6 5,5 5 4,5 4 3,5 3 2, m3/year 27 NIRAS

28 Trends in Denmark Increased gas production (~25%) per unit received material Increased reduction of solids Pre-treatment: Sterilisation at 70 and133 o C Reduced retention time (4-6 days termo-, 7-10 days mesophilic) Physical layout: 2 parallel lines, fewer pumps and moving parts Process monitoring and management Reduced capital cost 28 NIRAS

29 Land application/ after-treatment Direct application to field After treatment - separation After treatment - upgrading 29 NIRAS

30 Fertiliser effect Nitrogen uptake increased from 40 to >70% Phosphorous increased from ~30 to > 60 % Substitutes chemical fertiliser - adds organic matter to the soil Nutrients are recycled to land 30 NIRAS

31 THANK YOU! Anne Seth Madsen - [email protected] 31 NIRAS