Manure, the sustainable fuel for the farm

Transcription

1 Manure, the sustainable fuel for the farm Workshop name Venue, dd month yyyy Speaker s name

2 Workshop content Introduction Project planning Project implementation Biogas plant operation Economy 2

3 Introduction 3

4 Small scale Biogas Plants in (Remark: Please insert data or graph related to the biogas market in your country)

5 Incentives for the implementation of small scale biogas plants: Governmental Goals Emmission trading certificates Renewable Energy Law Subsidies Personal incentives: energy independancy, additional income 4

6 Biogas Technology 6

7 The Digestion Process Biogas (CH 4, CO 2 ) (wet) Biomass Solid, liquid manure, org. residues, energy crops Microbial (Biological) Process Digested substrate Nutrients Process conditions: - Under exclusion of air (anaerobic) - Moisture (max. 20 % DM in wet digestion) - Heat: 35 C 45 C (often), 50 C 55 C (rare) - Neutral to slightly alcaline ph-value

8 Manure Well-known feedstock; Potentially available in significant quantities; Good for co-digestion with other feedstock such as food waste; Economically feasible only if biogas digester is located at the place of manure production: transportation of manure is costly manure has relatively low-biogas yields.

9 Characteristics of Liquid Manure Collection Daily fresh supply is important! Manure store for longer periods of time (due to slatted/ perforated floors and manure cellar) decreases specific gas yield Preferable: Stables with external manure storage A manure system based on scrapers Usage of daily fresh manure Additional benefit: hygienic advantages on the stable atmosphere due to a reduction of harmful gases from the manure

10 Characteristics for Solid Manure Collection Quantity and quality of material removed from outdoor feedlots is influenced by uncontrollable climatic conditions Significant soil is removed during cleaning which leads to high ash content in the manure Dry matter content of harvested manure averaged 75% as compared to the original excreted manure that is approximately 10%. Ash content of harvested manure is approximately 66% as compared to a 20% ash content in excreted manure Organic matter content: 25-30% (50-80% excreted manure) 10/30

11 Organic Residues Old bread Apple pomace Spent grains / daff Biowaste (households) Grease trap Flotation fat Frying fat Vegetable residues Grain sweepings Cerial mash Glycerine Coffee draff Cacao shells Potatoe leafs Potatoe peels Potatoe mash Leafs Molasses Whey Fruit pomace Rape meal extract Colza cake Lawn cuttings Canteen / Catering Waste Onion peels Cosubstrates Energy Crops Corn Cob Mix Ensiled fodder peas Ensiled fodder beets Cereal mash Cereal straw Grass silage Rye total plant silage Oat silage Potatoes Potatoe mash Clover grass silage Alfalfa silage Corn seeds Corn silage Rape seeds Rye grains Red clover silage Ensiled beets (in general) Sun flower total plant silage Triticale total plant silage Triticale grain Wheat total plant silage Wheat grains Ensiled sugar beets..

12 Share of different digestible organic mass flow related to the total potential Energy crops 22% Landfill gas 5% Sewage sludge 11% Material from land conservation activities 3% Agricultural by-product 25% org. Residues 7% Slurry and Manure / Dung 27% Source: Handreichung Biogasgewinnung und nutzung, Fachagentur Nachwachsende Rohstoffe e. V. 1

13 The Gas C v H w O x N y S z Organic Substance Bacteria Heat Biogas: (composition) CH 4 : Vol-% CO 2 : Vol-% O 2 : 0 3 Vol-% N 2 : 0 5 Vol-% H 2 O: 0 10 Vol-% H 2, NH 3, H 2 S in ppm-level 1 m³ Biogas = 0,6 Liter Fuel Oil (with 60 Vol-% CH 4 )

14 Digestor Types Completely mixed reactor (standing): Slurry storage made of concrete or steel, mixed and heated, can come in differnt hights and widths Plug flow reactor (horizontal): Steel or concrete tank with paddle stirrer, heated

15 Biogas plants are operated in different ways:

16 Functional principle Through hydrostatic pressure, liquid level is at the same height in the connecting pipe Liquid levels balance themselves Overflow system communicating vessels Overflow works

17 The Conversion process Biogas Process heat to digester Energy conversion (CHP, Fuel cell) Energy for use Electric energy Thermal energy

18 Basic Components of a small scale Biogas Plant Vorgrube Feststoffeintrag Kondensatabscheider Rührkesselreaktor Endlager Überschusswärme BHKW Heizöltanks

19 Further plant components which could be necessary for the digestion of organic residues and energy crops: Reception bunker or pit Crushing technology Separation of impurities Hygienisation unit Hydrolysis tank Dosing unit

20 Advantages & Aims of Biogas Technology 1. Energy Production of gas, heat and power 2. Ferilizer value Avoidance of nutrient losses Reduction of plant corrosion Improvment of fluidity Improvment of plant compatibility Improvment of plant health Reduction of germination capacity of weed seeds 3. Environmental Compatibility Reduction of odour Reduction of methane and ammonia emissions Reduction of nitrate leaching Hygiensiation Recycling of organic residues Avoidance of sewer connection in remote areas

21 Feedstock & Microbiology 21

22 Biogas formation Biogas is formed by microorganisms that degrade organic material under anaerobic conditions Naturally occurs e.g. in landfills, bogs & mires, manure storage tanks Complex & interdependent process that happens in several stages

23 Feedstock for Biogas plants IBBK Fachgruppe Biogas GmbH

24 Dry matter (DM) Fresh matter (FM) Organic matter feedstock for microorganisms Feedstock (fresh matter) consits of: water + dry matter Water content Microbes eat volatile solids (= VS), Volatile solids [from % FM or % DM ] Mineral solids (ash)

25 The 4 Steps of Biogas Formation 1. Step Hydrolysis 2. Step Acidogenesis 3. Step Acetogenesis 4. Step Methanogenesis H 2 /CO 2 Biomass Polysacharids Proteins Fats Sugars Aminoacids Fatty acids Biogas CH 4 /CO 2 Fatty acids (Propionic acid) Alkohols Acetic acid H 2 hydrolytic Bacteria acidogenetic Bacteria acetogenic Bacteria methanogenetic Bacteria

26 The different degradation processes... occur at the same time simultaneously In agricultural biogas plants the separation of the degradation stages plays a minor role strongly depend on each other Intermediate products are needed for following processes can cause mutual inhibition Intermediate products may not accumulate Product inhibition one-stage process develop slowly in advanced stages Hydrolysis is the fastest, methane formation the slowest biogas digestate

27 Relative concentration [%] x Odour reduction of animal slurry through digestion Retention time [days]

28 An import basic substrate for biogas production: manure Mean values of few raw manure and digestate samples of Biogas plant Oberlungwitz DM [%] Nitrogen Ammonium Phosphorous Raw manure Potash Magnesium Calcium ph-value Digestate

29 Temperature ranges Thermophil (50-60 C) high gas yield after short retention time sensitive biocoenosis caution with rapid degradable substrates, (hydrolysis develops too fast) Mesophil (32-45 C) stable biocoenosis satisfying gas yield with acceptable retention time common, particularly in wet fermentation processes Psychrophil (< 25 C) low growth rate long retention times inefficient for biogas production no longer in use

30 Project planning 1 Process parameters 30

31 Dry matter contents Dry matter (DM): DM [%FM] = Measure unit for the sum of total solids in the substrat related to fresh mass Volatile Solids (VS): VS [%FM] = VS [%DM] = Measure unit for the sum of volatile solids in the substrat related to fresh mass Share of the volatile solids in dry matter Biogas production only possible from VS! Important: determination of degradable part of VS

32 (Hydraulic) Retention time t, HRT central planning parameter with manure plants less important parameter with energy crops or waste W orkingvolume[m³] HRT[d] m³ Daily SubstrateInput d x [days] Working Volume = Usefull reactor volume 6

33 Retention time of solid feedstock Solid feedstock is added by tonnage converstion to volume needed: Input Tonnage of solid feestock [t] [m³] t Density Digester Content m³ Density Digester Content 1 t/m³ 6

34 Example: daily manure input: 5 t/tag Digestor Working Volume: 300 m³ Gas space: 30 m³ VZ t 5 d t 1 m³ m³ 54 d Recommended retention times with mesophilic temperatur in digester: (depending on process and reactor) min max Liquid hen manure: Days Liquid pig manure: Days Liquid cow manure: Days Solid cow manure with straw: Days

35 Organic Loading Rate B R B R kgodm m³ d ( Drymatter Day) kgvs workingvolume[ m³] d Dry Matter (DM, VS, CSB, TOC) - Load per m³ working volume Tendency for higher loading rate (Energy crops, Waste) Alternative: Digester load - related to VS in Reactor (bacterial density) - at the moment no relevance 8

36 Project planning 2 Feedstock 36

37 Feedstock related biogas yields spez. Biogas yield [m³ Bioas /t Substrat ] Dairy slurry (8,5 % TS) 20 Pig slurry (6 % TS) 20 Poultry manure (15 % TS) 56 Total plant silage (38 % TS) 176 Corn silage ( 33 % TS) 185 Gras silage (40 % TS) 208 Weizenstroh (86 % TS) 292 Corn, dry (87 % TS) 590 Wheat grains (87 % TS) 598 Used oil & fat (95 % TS) 875 Kitchen waste (14 % TS) 48 Vegetable waste (15 % TS) 57 Source: LFL

38 Biogas yields from feedstock Is determined by: Ingredients of the substrate Organic content (volatile solids / VS) Proportion of fat, protein and carbohydrates Retention time in digester Form of preparation Process temperature Organic constituents Source: C. Tidjen, FAL Methane production Maize silage Process time [d] Gas yield [m 3 /kg] Methane content [%] Raw protein 0,7 71 Raw fat 1,25 66 Raw fiber 0,79 50 Free N extract materials 0,79 50 Source: Roediger

39 Detailed feedstock data Feedstock DM [% FS] odm [% FS] odm [% TS] Methane [Vol%] m³ch 4 / t ots m³ Biogas/ t FM Cow manure 8,5% 7% 85% 55% Pig manure 6% 5% 85% 60% Hen manure 15% 11% 75% 65% Maize corn dry 87% 86% 98% 53% Grass silage 40% 36% 89% 54% Wheat corn 87% 85% 98% 53% Maize silage 33% 32% 96% 52% Wheat straw 86% 79% 92% 51% Green grain silage 38% 35% 93% 53% Vegetable waste 15% 11% 76% 56% Kitchen waste 14% 11% 82% 60% Old fat 95% 87% 92 % 68% Manure Energy crops and agricultural subproducts Agroindustrial and slaughter house wastes Source: LFL Remark: values are general, for exact values an individual substrate analysis has to be undertaken!

40 Operators do s & dont s Do start slowly give microorganisms time to adapt Do provide stable conditions for your little co-workers: Regular feeding of same ration Maintain a constant temperature Do regular plant checks Keep a data log Don t be erratic & unreliable!

41 Project planning 3 Biogas plant components 41

42 Solids Feeder: Bunker size Planning and designing of Components Mixing pit: Storage time Digester: Organic loading rate, Retention time, Substrate mixing Substrate storage: Storage time Silo: Required area, Volume, Storage time CHP: Gas potential

43 Mixing pit Storage capacity max. ca. 5 days Leachate of silo and percipitation (if possible) Possibilities of mixing-in co-substrates Not too big: Mixing energy Solids feeder Sizing of feeding systems Storage capacity of min. 1 day Density of energy crops loose ca. 0,5 t/m³ Avoid too long storage time: composting! Control of mass flow instead of time

44 Digester sizing Design according to hydraulic retention time (manure based plants) days Design according to organic loading rate (energy crop and waste plants) Loading rate will be higher with more energy crops Less manure B R = ca. 4 kg ots/m³ d More manure B R = max. 2 kg ots/m³ d Future plant extention should be included in planning First step lower organic load => bigger digester than needed Easier operation from the beginning After a successful learing time organic load can be increased

45 Sizing digestate storage tank Digestate storage requirement Consider mass loss through biogas process Very low with liquid manure (ca. 5 %) Relatively high with energy crops and wastes (ca. 25 %) Very high with corn of grain (ca. 75 %) Formula for design (6 months storage): Necessary storage Vol.[m³] = (Substrate input[t] Mass loss[t]) / 2 Consider already available storage! Post digester = Storage volume

46 Sizing of CHP unit Expected gas yield and expected methane content Biogas [m³/a] * CH 4 -Cont. [%] = Methane yield [m³ CH 4 /a] Energy content methane: 10 kwh/m³ Methane yield [m³ CH 4 /a] * 10 kwh/m³ = Brutto energy [kwh/a] Elektrical efficiency h el (30 40 %) Brutto energy [kwh/a] * h el = Elektrical Energy [kwh/a] Desired full load hours h full = ca h/a Elektr. Energy [kwh/a] / h full [h/a] = theor. continous load [kw]

47 Environmental & Social benefits 47

48 Environmental Benefits Triple benefits for GHG-emission reduction: 1. Methane emission reduction through better manure management agricult. GHG 2. Energy production from biogas (power, heat, vehicle fuel) GHG from fossil fuels 3. Better fertiliser value less need for mineral fertiliser GHG from fertilser production 48

49 Environmental Benefits plus 4. Weed and pathogen control through AD 5. Phosphate recycling saves scarce P- sources 6. Reduced odour emissions from animal husbandry 49

50 Manure vs. Digestate Advantages of digestate low in odour appreciated by population improved plant compatibility better flowability easier soil penetration high share of NH 4 more effective, better control of fertilising effect, reduced leaching into ground water 50

51 Social Benefits AD gives farms & rural areas new perspectives: + Additional income for farms (or reduced energy costs, e.g. through self-supply in Belgium) + Local companies are involved in construction of AD plants, maintenance and repair Support of SME in rural areas Strengthening of a regional financial circuit 51

52 Social Benefits from renewables facts from Germany (status quo 2012) Decentral (renewable) energy production diversification of energy supply 50% of renewable energy plants are owned by citizens (partly aiming at supplying regional energy) 754 energy cooperatives 70 new public service companies since 2005 Source: IÖW: Wertschöpfung durch Erneuerbare Energien, SR 210/15, Dez

53 Social Benefits from renewables facts from Germany (status quo 2012) Direct national added value from renewables: 18.9 billion 12.5 billion (= 66 %) remain on communal/ municipal level full-time jobs, 75 % in planning, production & installation Source: IÖW: Wertschöpfung durch Erneuerbare Energien, SR 210/15, Dec

54 Main messages Manure is available free of costs Additional income for farms AD is good for the environment 3-fold reduction of agriculture s CO 2 - footprint AD makes rural live more attractive Creates or keeps jobs in rural areas Less smell from animal husbandry 54

55 Legal disclaimer Die alleinige Verantwortung für den Inhalt dieser Präsentation liegt bei den AutorInnen. Sie gibt nicht unbedingt die Meinung der Europäischen Union wieder. Weder die EASME noch die Europäische Kommission übernehmen Verantwortung für jegliche Verwendung der darin enthaltenen Informationen. 55