Gobar Gas Plant construction
Class IX
Bio gas for village…

Bio gas is a clean unpolluted and cheap
source of energy in rural areas. It consists
of 55-70% methane which is inflammable.
Bio gas is produced from cattle dung in a
bio gas plant commonly known as gobar
gas plant through a process called
digestion.
Objectives

1. To provide fuel for cooking purposes
and organic manure to rural house holds
through family type Bio Gas Plants.
2. To mitigate drudgery of rural women,
reduce pressure on forests and accentuate
social benefits.
3. To improve sanitation in villages by
linking sanitary toilets with bio gas plants.
Construction Technique – Need to
keep in Mind
Site Selection
 Digging of the pit
 Foundation laying
 Machinery construction work
 Laying of pipeline and accessories
 Precautions in lying pipelines.
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A lay out Model of Gobar gas plant
Components required for Bio gas
plant
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Mixing tank and inlet
Digester
Gas holder or gas storage dome
Outlet and compost pits and
Gas main outlet and valve, pipeline,
water fittings, gas stoves, lamp and
similar appliances run on bio gas.
Feeder (Raw materials) from the
Villages
Cow dung
 Human waste (link latrine to the Gas plant)
 Animal waste
 livestock and poultry wastes, night soil,
crop residues, food-processing and paper
wastes, and materials such as aquatic
weeds, water hyacinth, filamentous algae,
and seaweed.
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Construction Process…
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First a pit is dug, perhaps ten feet deep.
Then a water-tight cement cylinder (with
brick or gravel) is constructed. Next, a wall
is built across the middle, extending up
from the bottom, not quite to the top.
Intake and outgo pipes are installed. The
whole unit is water-tight.

The manure is mixed with water in the
Intake basin to make a slurry, which then
goes down the pipe to the bottom of the
left side. This side of the cylinder
gradually fills and overflows to the right
side. Meanwhile, the whole mass bubbles
methane up to the top. It collects under the
large metal bell-like cover. The gas builds
pressure, and can be taken off through a
rubber tube to a gas stove in a kitchen.
Model of Gas plant
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When both sides of the cylinder are full,
the effluent flows out from the bottom of
the right side each time more raw manure
is added to the left. What comes out on the
right is of more value as fertilizer than the
raw manure. So the methane is an added
byproduct literally "something for
nothing," once the capital expense of the
construction is paid.
Cost estimate…
Capacity of
Sl. no.
plant
retention
period
Unit cost
1
1 cu. m
40 days
4700/-
2
2 cu. m
40 days
6500/-
3
3 cu. m
40 days
7600/-
4
4 cu. m
40 days
8700/-
Subsidy available to Villages
Central
subsidy
for others
State subsidy under Anila
Yojane SF MF AL SC ST
Hilly areas
State subsidy
for Hilly
areas not
approved
from
central
governm
ent
Total
Size of Plant
(in cu.
m)
Central subsidy for SF,
MF AL SC ST Hilly
areas
1
2300
1800
1500
2000
3800
2
2300
1800
3500
4000
5800
3
2300
1800
3500
4000
5800
4
2300
1800
3500
4000
5800
Advantages
(a) Large cattle population in the countryside
ensuring steady source of supply of the
raw material required for running the gas
plant.
(b) Helps in reducing the deforestation as it
arrests for cutting of trees for firewood.
(c) Helps in maintaining ecological balance.
(d) Helps in rural sanitation
(e) Lower capital cost and almost cost free
maintenance.
(f) Removes drudgery of women.
Uses of Gobar Gas…
Generally the uses of the gas can be as under
1) cooking
2) lighting
3) Motive Power a) run pump set b) chalfcutter
4) can produce electricity.
Motive Power can be produced by linking
the Gobar Gas to a duel fuel engine,
specially designed for Gobar Gas.
Courtesy

http://www.unu.edu/unupress/unupbooks/8
0434e/80434E0k.htm