Rakičan, 2007

BIOGAS FOR FARMING, ENERGY CONVERSION AND ENVIRONMENT PROTECTION

Kestutis NAVICKAS

Department of AgroenergeticsLithuanian University of Agriculture

29 Novembra 2007, Rakičan

Rakičan, 2007

INSPIRATIONS FOR BIOGAS

Political - Kyoto protocol, EU and national legislations

Environmental – reduction of organic and biological

pollution

Veterinary – treatment of animal by-products not

intended for human consumption

Energy – replacement of fossils to local resources

Recovery – production of new products from wastes

Agricultural – waste treatment, fertilizers

Social – labor market and regional development

Rakičan, 2007

100 120 139 159 186274

370450

617

8501050

1600

1800

2000

2400

2800

3500

0

500

1000

1500

2000

2500

3000

3500

Nu

mb

er

of

pla

nts

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

P. Weiland, 2007

Development of biogas industry in Germany

Rakičan, 2007

Process design

Technology flows and elements

Substrate

collection and holding

pretreatment - separation, cutting, mixing, sanitation

loading and removal

digestate storage and utilization

Process

mixing

heating

Biogas

collection and holding

conversion

Rakičan, 2007

AD Process scheme

British Biogen

Rakičan, 2007

Process parameters

Temperature

Psychrophilic (10oC - 25oC)

Mesophilic (25oC - 45oC)

Thermophilic (55oC - 60oC)

Hydraulic retention time HRT

(the average time the substrate remain in a digester)

HRT = Vl / Sd (Vl – liquid volume, Sd – daily flow)

Cattle manure - 12 – 18 days

Pig manure - 10 – 15 days

Organic loading rate OLR

(organic material fed daily per m3 of digester volume)

Cattle manure - 2.5 –3.5 kg VS/ m3 day

Pig manure - 3.0 –3.5 kg VS/ m3 day

Rakičan, 2007

Process indicators

SUBSTRATE

• Composition (TS, VS, Proteins, Fats and Carbohydrates)

• pH level (about 7.0)

• Rate of C:N

• Biogas yield potential (m3/kg substrate or m3/kg TS)

BIOGAS

• Biogas rate (m3/m3 of digester volume per day)

• Biogas composition and energy potential

OTHER

• Energy efficiency or biogas utilization factors

• BOD and COD in feed and removal or VS in feed and removal

• Pay back

Rakičan, 2007

Biogas yields from different biomass

25

30

35

35

55

80

80

350

400 800

75

110

200

0 100 200 300 400 500 600 700 800

Biogas yield, m3/t

Pig manure

Cattle manure

Poultry manure

Fruit and vegetables

Dairy waste

Distilary waste

Sewage waste

Vegetable oil

Fatty wastes

Used fats

Mangel

Grasses

Maize

Rakičan, 2007

Biomass for biogas

Rakičan, 2007

0

50

100

150

200

250

300

350

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Weeks

Su

bst

rate

, t

0

2

4

6

8

10

12

Bio

gas,

103

. m

3

manure industrial waste biogas per week

Influence on biogas production of the industrial substrate

Rakičan, 2007

Composition of Biogas

Component Dimension Content

CH4 % 55 - 80

CO2 % 15 - 45

H2S mg/m3 0 - 5000

NH3 mg/m3 0 - 450

Humidity - Saturated

Caloric value MJ/m3 20 - 25

Caloric value kWh/m3 5,5 – 8,0

Rakičan, 2007

Biogas useBIOGAS

Boiler Cogenerator Fuel cell Storage

Conversion Compression

Electricity Heat Electricity Heat Liquid fuelHeat

Separation of sulphur, dust and moisture

Upgrading

Rakičan, 2007

Cogeneration

Bio

mass

en

ergy p

ote

nti

al

100%

Gas

engine

Mechanical energy 35,4

%

Th

erm

al

en

ergy 6

1.7

Effluent gas

36,1%

Liquid

cooler

26,6 %

Effluen

t gas c

ooler

Effluent gas

25.8%

Losses of heat transmission

2,9%

Heat exchanger

of liquid cooler

Heat

exchanger

of effluent

gas

Power

generator

35,4%

Heat energy

57.3 %

Electrical energy

33,9 %

21.9% Losses

8.8%

0.3%3.5%

0.6%

2.9%

1.5%

10,3%

Rakičan, 2007

Pig Farm Biogas Plant, Lithuania

60 m3 pig manure / day + Industrial wastes: ~ 3 t / day

Digester: 3 x 300 m3 horizontal steel digesters

Biogas production: 1200 - 2500 m3/d

Co-generation: 1 x 75 kW and 1 x 110 kW

2 x 300 kW gas burners

Rakičan, 2007

Pig Farm Biogas Plant, Lithuania 2

90 m3 pig manure / day + Industrial wastes: ~ 10 t / day

1 x 2000 m3 vertical steel digester

Biogas production: 3000 - 3500 m3/d

Co-generation: 4 x 150 kWel

Rakičan, 2007

Laboratory

Rakičan, 2007

Potential problems of anaerobic digestion

Waste management create traffic movements for wastecollecting and digestate transporting to the land. Accidentsof waste transporters can cause pollution of environment.The potential noise can be given from deliveries, pumps,compressors, mixers etc.There may also be some risk of fire and explosion, althoughno greater than with systems using natural gasEmployers of people working in biogas plants must assessthe risk from exposure of the gases, pathogens in thefeedstocks and to control that riskTransportation of animal by-products creates some risksfor health and risk of animal disease transmission betweenfarms.

Rakičan, 2007

Benefits for environment

Mitigation atmospheric methane concentrationsreduces impacts on global climate change

Treatment of wastes reduces water, airpollution, odors and destroys pathogens

Application of digestate fulfils the phosphorusrequirements of the crops and completes thenitrogen requirements from mineral fertiliser.

Displacement of fossil fuels reduces CO2

emissions

Rakičan, 2007

Farming benefits

Diversification of farming activities;

Reliable energy production and utilisation;

Additional earnings from waste treatment, production of energy and fertilisers, selling of green certificates;

Improvement of the mechanical and nutrition properties of manure;

Rakičan, 2007

Thank you for attention!Kestutis NAVICKASDepartment of Agroenergetics

Lithuanian University of AgricultureStudentu 11, LT-53361,Akademija, Kaunas distr.LITHUANIA

E-mail Kestutis.Navickas@lzuu.ltTel. + 370 68 78 68 26Fax. + 370 37 75 22 71