Biogas-energy of the future

1. Energy of the future

2. Biogas is a mixture of gases produced by the breakdown
of organic matter in the absence of oxygen. Biogas is
produced by anaerobic digestion with anaerobic bacteria
or fermentation of biodegradable materials such as manure,
sewage, municipal waste, green waste, plant material, and
crops.
COMPONENTS PERCENTAGE
Methane (CH4) 50-75
Carbon Dioxide (CO2) 20-50
Nitrogen (N2) 0-10
Hydrogen (H2) 0-1
Hydrogen Sulphide (H2S) 0-3

3.  Fixed dome type
 Floating drum type
 ARTI type
 Nisargruna (BARC) type

4. Advantages:
◦ easy to operate
◦ Provide gas at
constant pressure
 Disadvantages:
◦ Expensive
◦ Rusting
◦ Requires regular
maintenance

5.  Advantages:
◦ Easy to construct
◦ Inexpensive
 Disadvantages:
◦ Its volume is fixed.
So the gas pressure increases inside
◦ Plant must be gas-tight (no leakage)

6.  This model is developed by Dr. Anand karve (President of ARTI) in
2003
 It uses starchy or sugary (kitchen waste, leftover food, green
leaves)feedstock instead of low calories influent like cattle dung (or
conventional feed stock).
 2 kg of such feedstock is able to generate 500gm of methane.
 Around 10,000 such plants are operational in Maharashtra and few
plants are also installed I other parts of India as well.
 It is 20 time as efficient as conventional biogas plant.
 Effluent is watery so easy to handle.
 This design have won Adshen award for sustainable energy in 2006.

8. Conventional
Biogas system
ARTI Biogas
system
Amount of feedstock required 40kg +40lit water 1-1.5kg +15 lit
water
Nature of required feed stock Dung Any starchy
material
Reaction time 40 Days 48-72 hours
Standard size of household 4000 lit 1-1.5 kL
Capital investment per unit
INR 20,000 INR 10,000
including stove
Amount and nature of slurry to
be disposed
80 lit sludge 15 lit watery
Running expense per meal INR 25 0 to INR 5

9.  Influent get choked in inlet pipe, so influent should be
chopped properly before mixing in water.
 Leakage of gas occurs due to its design which causes 10-20%
loss of biogas.

10.  Developed by Dr. S. P. Kale (Scientist BARC) around 2005
 It uses biodegradable kitchen waste, paper waste, green grass, leaf
litter, animal remains in abattoirs, hospital waste, green plant waste,
cow dung, crop residues, sugarcane, baggase, water hyacinth, etc.
 Major focus of this plant is to manage municipal solid waste.
 The waste is first segregated carefully to remove non-biodegradable
material and then homogenized to make a slurry. It is then
processed in a sequential manner first by aerobic and then by
anaerobic process
 About 70% of Water can be recycled at the end of the process.
 based on thermophilic microorganisms and microbial processes
develop the design of the biogas plant. The plant is completely
gravity based.

12. 1. Mixer 5. Main digester tank
2. Pre- mix tanks 6. Dome
3. Solar heating system 7. waste water tank
4. Pre digester tank

13.  Mixing stage:
The waste that enters the Nisargruna Bio-digesters has to be
properly segregated as some materials may detrimentally affect the
efficiency of the plant and may spoil the mixer blades as well as
interfere with the microbial activities in both the aerobic and
anaerobic digesters;
 Pre-treatment Stage:
The introduction of the high temperature water in the aerobic
digester is essential for the breakdown of the sulphurus and other
toxic products that may be present in the waste. To maintain aerobic
condition air compressor is used.
 Anaerobic Digestion Stage:
The two stage digestion helps in improving the purity of the
methane gas, of up to 90%, thereby increasing its fuel efficiency
when burned. However, this purity is dependent on how
effectively the pre-digester temperatures are maintained and
the amount/ quality of the waste that enters the system.

14.  Gas produced from Nisargruna plant has
o Methane: 70-75%
o Carbon Dioxide: 10-15%
o Water vapors : 5-10%
Gas produced from nisargruna biogas plant has high methane
content.
Infrastructure Required
The following infrastructures required for set-up a 1 tonne/day
capacity Bio gas plant:
 Space : ~ 300 m2
 Manpower : Two unskilled persons for operation
 Power supply : 3 phase AC
 Water Supply : 1.2 kL for one tonne plant

15. Sr.
NO.
ORGANIC WASTES ESTIMATED QUANTITY
1 Municipal Solid Waste 30million tons/year
2 Municipal liquid Waste 1200 million lt./day
3 Distillery (243 units) 8057 kilolitres/day
4 Press mud 9 million tons/year
5 Food & fruit processing wastes 4.5 million tons/year
6 Willow dust 30000 tons/year
7 Dairy industry waste 50-60 million lt./day
8 Paper & pulp industry waste (300mills) 1600 m3/day
9 Tannery (2000 units) 52500 m3waste
water/day

16. Sr.
No.
Raw Materials Biogas production
inlts/kg
Methane content
in Biogas (%)
1 Cattle Dung 40 60.0
2 Green Leaves & Twigs 100 65.0
3 Food waste 160 62.0
4 Bamboo Dust 53 71.5
5 Fruit Waste 91 49.2
6 Bagasse 330 56.9
7 Dry Leaves 118 59.2
8 Non E 242 67.5

17.  Cooking: Biogas can be used in a specially designed burner for
cooking purpose. A biogas plant of 2 cubic metres capacity is
sufficient for providing cooking fuel needs of a family of about five
persons.
 Lighting: Biogas is used in silk mantle lamps for lighting purpose.
The requirement of gas for powering a 100 candle lamp (60 W) is
0.13 cubic meter per hour.
 Power Generation: Bio Biogas can be used to operate a dual fuel
engine to replace up to 80 % of diesel-oil. Diesel engines have been
modified to run100 per cent on biogas. Petrol and CNG engines can
also be modified easily to use biogas.
 Transport Fuel: After removal of CO2 H2S and water vapour, biogas
can Be converted to natural gas quality for use in vehicles.

18.  Purification is carried out to enrich biogas by scrubbing off
the unwanted components i.e. carbon dioxide (CO2) and
hydrogen sulfide (H2S).
 It is essential to have more energy per unit volume of
compressed biogas and to get rid of the corrosive effect of
H2S.
 Various purification processes include absorption into water,
absorption by chemical, pressure swing adsorption and
membrane separation.
 One of the simple and cheap method is the use of
pressurized water as an absorbent liquid.

19.  Water is good solvent for CO2 and it is most suitable method for
rural areas.
 The solubility of CO2 in water is governed by variation in pressures
and temperatures

21.  Biogas is an important renewable energy resource for rural areas
in India.
 It is an environment friendly, clean, cheap and versatile fuel.
 Average calorific value of biogas is 20 MJ/m3(4713 kcal/m3).
 Biogas like Liquefied Petroleum Gas (LPG) cannot be liquefied
under normal temperature and pressure.
 An estimate indicates that India has a potential of generating
6.38 X 1010 m3 of biogas from 980 million tones of cattle dung
produced annually .
 The heat value of this gas amounts to 1.3 X 1012 MJ . In addition,
350 million tones of manure would also produce along with
biogas.
 To make biogas suitable for automobile application, the enriched
biogas was compressed up to 20.0MPa after moisture removal
and filled in special high pressure seamless steel cylinders (as
used in CNG filling)

22.  MNES Report (2001) Renewable Energy in India and business
opportunities. MNES (Ministry of Non-conventional Energy Sources),
Government of India, New Delhi.
 http://www.barc.gov.in/technologies/kitchen/Kitchen.html
 http://www.barc.gov.in/akruti-tp/atp_nisar.html
 MIT Co Lab, Sustainable management of organic wet waste in
developing cities.
 The 2nd Joint International Conference on “Sustainable Energy and
Environment (SEE 2006)” C-003 (O) 21-23 November 2006,
Bangkok, Thailand