Bio-Gas and Its Types

1
Bio-gas Plant and Its Types

• Made By Rishabh
• X-A
• Roll No.-24

2
Bio-Gas

• Biogas is obtained by anaerobic fermentation of
  animal waste like animal dung and plant waste by
  anaerobic bacteria is presence of water but in
  absence of oxygen.
• Biogas is a mixture of Methane (75), Carbon
  Dioxide (23), Hydrogen and Hydrogen Sulphide.
• The anaerobic bacteria decomposes the carbon
  compound present in the animal and plant wastes
  in form of carbohydrates, proteins and fats into
  methane gas. Some of these bacteria breakdown
  biomass to sugars, organic acids and other
  compounds which are further decomposed by other
  bacteria to form carbon dioxide and hydrogen.
  These combine to form methane and water. The
  reaction is CO24H2 CH42H2O

3
Fixed Dome Type Biogas Plant

• A fixed dome type biogas plant consists of an
  inlet chamber or mixing chamber where slurry of
  animal dung and other waste material is prepared
  by adding equal amount of water.

4
Fixed Dome Type Biogas Plant

• The slurry is then passed to the underground
  digester tank. It is a closed tank made by laying
  bricks. These are sealed chambers.
• Organic waste material undergoes decomposition by
  microorganisms and biogas is produced which is
  collected in gas holder from where it is supplied
  to consumers.

5
Fixed Dome Type Biogas Plant

• The residue left in digest tank is removed
  through the outlet chamber and is now called
  spent slurry.
• This spent slurry is used as manure because it
  contains compounds rich in nitrogen and
  phosphorus.

6
Fixed Dome Type Biogas Plant
Full Working
7
Floating Gas Holder Type Biogas Plant

• This type of biogas plant consists of a well
  shaped underground tank called digester tank.
• The sides of digester tank are made of bricks and
  base is made of concrete.
• A drum shaped gas holder made of steel floats in
  inverted position over the dung slurry. The gas
  collects in floating gas holder.

8
Floating Gas Holder Type Biogas Plant

• The gas holder can move up or down and its
  movement is controlled by control pipe.
• The Biogas comes out form the outlet at the top
  of gas holder tank.
• The digester tank has a partition wall, which
  divides it into two chambers and helps in
  increasing gas pressure

9
Floating Gas Holder Type Biogas Plant

• On left side of the tank is an inlet pipe made of
  cement which is connected to a mixing tank.
• This inlet brings fresh dung slurry into digester
  tank.
• On right side of digester tank is an outlet pipe
  made of cement which is connected to an over-flow
  tank.
• This outlet pipe removes spent slurry.

10
Floating Gas Holder Type Biogas Plant

• Working
• Cattle dung and water are mixed in equal
  proportions in the mixing tank to prepare the
  slurry which is fed to digester tank through an
  inlet pipe.
• The slurry is left in digester tank for 50 to 60
  days. This dung undergoes anaerobic fermentation
  and forms biogas which collects in the gas
  holder.
• The pressure of biogas increases in the gas
  holder with increasing amount.

11
Floating Gas Holder Type Biogas Plant

• Since the gas holder cannot rise up beyond a
  certain point, increased gas pressure pushes the
  spent slurry from the digester tank into
  over-flow tank.
• This spent slurry is taken off and used as
  manure.
• More fresh slurry is added and thus biogas is
  produced.

12
Floating Gas Holder Type Biogas Plant
13
Floating Gas Holder Type Biogas Plant

• Its Disadvantages
• It is more expensive as its gas holder drum is
  made of steel.
• Defects in welding of gas-holder and corrosion of
  steel can lead to leakage of biogas.
• Its maintenance cost is high as gas holder of
  this plant is to be painted frequently to save it
  from corrosion.

14
Thank You