Agricultural Structures-BIOGAS PLANT Flashcards
Used to process animal wastes or manure to produce biogas and sludge.
Biogas plant
Consisting of an
inlet/mixing tank, digester, gas chamber and outlet/sludge tank.
Biogas plant
Biogas plant where the digester and gas chamber form one unit.
Integrated plant
Digester and gas chamber form separate units.
Split-type Plant
Plant with series of digesters.
Multi-digester plant
Plant consisting of digester and a moving, floating gasholder that either float directly in the
fermenting slurry or in a separate water jacket.
Floating type
Closed digester with an immovable, rigid gas chamber and a displacement pit.
Fixed type
Plant consisting of a heat-sealed plastic or rubber bag, combining digester and
gasholder.
Balloon type
Chamber where manure and water are collected, stored and separated from heavy and non-
biodegradable materials before feeding them into the digester.
Collecting tank
Serves as conveyor of the manure-water mixture or slurry from the mixing tank to the digester.
Inlet pipe
Any water and air tight container designed for the process of anaerobic microbiological degradation of organic matter into which the slurry is introduced for digestion and methanization.
digester
biodigester
bio-reactor
anaerobic reactor
Division in the digester that prevent the slurry from premature exit into the sludge/outlet tank.
Baffle board
Mechanical device inside the digester used to stir the slurry.
stirrer
mixer
agitator
Space inside or outside the digester for the collection and storage of biogas.
Gas chamber
Cantilever beam that holds the gasholder/movable cover in position at the desired biogas
pressure.
Gasholder retainer
Serves as conveyor where the effluent or the slurry is forced out.
Outlet pipe
Layer of compacted soil and gravel to support the digester wall.
Backfill
Amount of slurry fed per unit volume of digester capacity per day.
Loading rate
organic material used to produce biogas
Substrate
adding or introducing anaerobic bacteria to the digester
Seeding
mixture of manure and water
Slurry
difference in height between the digester wall and the filling line
Freeboard
level of slurry when the digesters is at full load
Filling line
average period that a given quantity of slurry is retained in the digester for digestion
Retention time
materials that inhibit the normal growth of pathogens in the digester such as mineral ions, heavy metals and detergents
Toxic materials
materials that inhibit the normal growth of pathogens in the digester such as mineral ions, heavy metals and detergents
Toxic materials
various processes that take place among the methanogens, non-methanogens and substrates
fed into the digester as inputs
methanization
digestion
anaerobic bacteria that act upon organic materials and in the process, produce biogas
Methanogens
temperature range of 20 oC – 40 oC where mesophilic bacteria operates
Mesophilic temperature rage
amount of biogas produced per day per cubic meter of slurry
Gas production rate
mixture of gas (composed of 50 to 70 percent methane and 30 to 40 percent carbon dioxide)
produced by methanogenic bacteria
Biogas
layer of floating material (mainly fibrous) on the slurry
Scum
settled portion or precipitate of the slurry; a mud-like, semi-solid mass
Sludge
residue that comes out at the outlet after the substrate is digested/processed inside the digester
Effluent
The minimum diameter of the inlet pipe shall be
0.2m
Retention time for liquid pig manure
15 to 25 days
Retention time for liquid cow or carabao manure
20 to 30 days
Retention time for liquid chicken manure
20 to 40 days
Retention time for animal manure mixed with plant materials
50 to 80 days
For Balloon Type:
The digester volume is ___% of the total digester volume is occupied by the slurry.
80%
The minimum diameter of the outlet pipe shall be ___.
0.2m
For fixed type, the volume of the outlet tank shall be ____ of digester volume occupied by the slurry.
1/3
The tank should be concreted and a ______ should be provided to control or allow the proper mixture of water and manure.
Sluice gate
The floor of the mixing tank should be inclined from ______ toward the inlet pipe and it should be elevated at least ___ from the filling line.
8.5% to 17.5% ; 0.2m
Concrete pipe (prefabricated RC pipe) should be used and it should be inclined ____ with digester wall.
58%
Lower end of inlet pipe should be positioned below the gasholder retainer for floating type. If there is no retainer, the lower end should be located ____ from the floor of the digester.
100mm
Manhole cover should be _____ in
diameter and _____ thick.
0.65m ; 0.125m
The floor shall have a slope of about ____ from the inlet to the outlet
2.5%
The gas drum should consist of ____ mild steel sheets for the sides and ____ sheets for the top.
2.5 mm ; 2mm
The gas drum should have a sloping roof of _____ and it should be provided
with guide frame.
16.5%
