training on biogas and biomethane production - eihp · benchmarks for biogas production: usable...

Training on Biogas and

Biomethane Production

Biogas Production- Information for a successful biogas plant operation -

� Biogas plant technology

� Gas upgrading, injection and grids

� Sustainability

� Demand oriented energy supply

� Hessian Biogas Research Centre

(HBFZ)

Fraunhofer IWES

Division Bioenergy and System Technology

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Content

Feedstock materials

Digestion

Biogas

Energy Production

Digestate

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Biogas Production - Feedstock

X

X X

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X

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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 !


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Feedstock properties:

Fresh matter (FM) [kg]

Water content (% of FM) [kgH2O/kgFM]

Dry matter (DM) [kgDM/kgFM]

Organic dry matter (oDM) [kgoDM/kgFM]

Density substrate (ρ) [kg/L] ~ 1

Specific gas yield (YGas) [LGas/kgoDM, in]

Methane concentration (cCH4) [Vol.-%]

Availability:

Own premises [tooDM/ha*a]

Delivery contracts [tooDM/a]

Biogas Production - Digestion

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Carbo hydrate

Fat

Protein

manure

wastes

plants

Acetic acid

Hydrogen

Carbon dioxide

hydrolytic acidogenetic

bacteria

Methane

Carbon dioxide

Biogas

acetogenetic methanogenic

bacteria

Fatty acids

Gases

Alcohols

Sugar

Carboxy acids

Amino acid

Bases

1st step

cracking

macromolecules

2nd step

digesting

monomers

3rd step

formation of

methanogenic

substrates

4th step

biogas production

Biological degradation of organic compounds in 4 steps:

Different populations with partly contradicting ambience preferences

Activity hampered by own metabolites

Ambient conditions in a digester are a compromise


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source: http://www.eon-bayern.com/pages/eby_de/

Dienstleistungen/Waerme/Biogas/Biogasanlage_Schwandorf

§ €


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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

BEKON Dranco


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Benchmarks for biogas production:

Usable volume digester (VR) [m³]

Mass flow feedstock (m´) [kgFM/d, kgoDM/d]

Dry matter feedstock (DM) [kgDM/kgFM]

Dry matter in digester (DM) [kgDM/kgFM], 0,05-0,15

Organic dry matter (oDM) [kgoDM/kgFM], ~ 0,05

Retention time (tr) [d], 20-100

calculation: tr = VR*ρ/m´

Minimum 20d!

Volume load(LV) [kgoDM/(m³R*d)], 1-20

calculation: LV = m´*oDM/VRMaxima: maize silage 3, manure 5, waste 20 kgoDM/(m³R*d)

Always check

both

parameters !!!

Biogas Production - Biogas

Biogas Composition

Gas component Vol.-%

Methane 40-75

Carbon dioxide 25-60

Nitrogen 0-7

Oxygen 0-2

Hydrogen 0-1

Hydrogen sulphide 0-1

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Elemental sulphur formed by

bacteria which digest H2S


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Micro gas-

turbinePilot injection

Diesel engine

Biogas Production - Energy

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Benchmarks for energy production:

Biogas production (V´Gas) [m³N/d]

Calculation: V´Gas = m´*oDM*YGas

Power, gross (Ptotal) [kWh/d]

Calculation: Ptotal = V´Gas*cCH4*Hi,CH4Net calorific value methane Hi,CH4 10 kWh/m³NPower, electric (Pel) [kW]

Calculation : Pel = Ptotal*ηel/0,9 for Diesel

Electrical efficiency CHP 35-42%

Power, thermal (Pth) [kW]

Calculation: Pth = Ptotal*ηth/0,9 for Diesel

Thermal efficiency CHP 45-55%

Biogas Production – Energy

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Benchmarks for energy production:

Energy, electric (Eel) [kWhel/a]

Calculation: Eel = Pel*hmax-Eel,auxFull load hours (hmax) [h/a] Eel/Pel

Auxiliary power (Eel,aux) [kWhel/a] ~ 3-15% of Eel

Energy, thermal (Eth) [kWhth/a]

Calculation: Eth = Pth*hmax-Eth,auxFull load hours (hmax) [h/a] Eel/Pel

Auxiliary power (Eth,aux) [kWhth/a] ~ 50% of Eth

Biogas Production – Digestate

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Utilization of digestate to be done preferably in the most cost effective way

spreading on agricultural land most common method

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

Power of biogas plant

[kWel]

Digester residue production

[t/a]

Application area

[ha]

500 10 000 200

1 000 20 000 400

8 000 160 000 3 200


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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 …


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Digestate treatment – processes

Mechanical Chemical Thermal

Centrifugal

separation

Precipitation

with CaPO4

Drying

Membrane

separation

Precipitation

with MAP

Stripping

ammonia

Pressing Evaporation


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Screw press separator

[UTS Products GmbH]

[UTS Products GmbH]


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Decanter centrifuge

[Fa. Spaleck Oberflächentechnik GmbH]

Source: modified after HEMMING & WAGNER (2008)


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Filter presses – Belt filter press

[Fa. Passavant Geiger GmbH] [Fa. Passavant Geiger GmbH]


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Ultra filtration process


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Solar drying with the „electric mole“

[Fa. Thermo-System Industrie - & Trocknungstechnik GmbH]

[Fa. Thermo-System Industrie - & Trocknungstechnik GmbH]


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Drum drier

[Fa. Dörfler GmbH] [Fa. Dörfler GmbH]

Training on Biogas and Biomethane Production

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Thank youfor your attention.

Do you haveany questions?

[Copyright: Schmack Biogas AG]

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Contact:

Henning Hahn

Fraunhofer IWES

Division Bioenergy and System Technology

Königstor 59

34 119 Kassel, Germany

[email protected]

www.urbanbiogas.eu

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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 = 170-250 m³ Biogas

1 m³ biomethane = 1 l oil equivalent

1 m³ biomethane = 3.3 – 4.3 kWhelBiogas plant electricity demand: 5-25 %

Biogas plant heat demand: 5-25 %

Necessary labour hours: 8-10 lh/kWel installed

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organic waste sourceDM oDM biogas yield biogas yield

methane

content

[%] [% of DM] [lN/kg oDM] [m³/t FM] [%]

old bread 65.0 97.0 760 482.0 53

fats 95.0 92.0 1000 874.0 68

Organic waste from priv. households 32.0 71.9 350 81.0 63

grease trap removal sludge (liquid) 5.0 90.0 1000 45.0 68

grease trap removal sludge (solid) 97.0 95.0 870 743.0 65

flotate sludge 15.0 93.0 700 63.0 59

potato (fruit-water - starch production)3.5 62.9 727 16.0 71

potato (process-water - starch production)1.6 81.3 423 6.0 65

potato pulp 14.0 93.0 610 79.0 55

potato pulp (pressed, from starch

production) 25.0 94.0 610143.4

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potato shells 12.7 92.0 880 103.0 52

potato grain 6.0 87.0 670 35.0 56

cheese waste 79.0 94.0 900 674.0 68

molasses 73.0 78.0 430 247.0 55

rumen content 15.0 86.7 300 39.0 60

rape press cake 90.0 82.0 630 465.0 63

rye powder 87.8 96.8 680 576.0 54

rye grain 5.5 95.0 670 35.0 55

sour whey (diluted) 4.0 89.0 550 19.5 63

sour whey (fresh)21.8 94.9 670 138.7 67

food waste 18.2 92.9 856 144.7 56

whole milk (fresh) 13.0 95.0 900 111.2 63

cabbage slices waste 12.5 88.0 no data 88.1 55

onion slices 82.0 67.0 490 267,8 65

training on biogas and biomethane production - eihp · benchmarks for biogas production: usable...

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