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Biogas

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Kashmeera N.A.
Kashmeera N.A.

This document discusses biogas production through anaerobic digestion. It describes the key components of a biogas plant including the digester, gas holder, inlet, and outlet. The four step process of biogas production is outlined as hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Major genera of methanogenic bacteria that create methane are discussed. Factors that influence methane formation like pH, temperature, nitrogen concentration, and carbon to nitrogen ratio are also summarized.

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KASHMEERA N.A. IV SEM MSc ZOOLOGY ROLL No: 37 03/13/13
03/13/13
03/13/13
Mystery unveiled…. Alessandro volta 03/13/13
BIOGAS • Mixture of gases. • Produced by anaerobic digestion of organic matter. • Consist of CH4 ,CO2 ,traces of H2 & other gases. 03/13/13
Composition of Biogas 03/13/13
03/13/13
BENEFITS FROM BIOGAS PLANTS • Used mainly for cooking & lighting purposes. • Used in internal combustion engines to power water pumps & electric generators. 03/13/13
• Used as fuel in fuel type refridgerators. • Sludge - fertilizer. • ↓ envt. pollution 03/13/13
03/13/13
SUBSTRATE • Plant & animal biomass. • Plant biomass – • Animal biomass – cattle dung,manure from poultry,goats & sheep slaughter house & fishery wastes. • Agricultural wastes also used 03/13/13
03/13/13
Parts of biogas plant • Digester • Gas holder • Inlet • Outlet 03/13/13
Inlet chamber • To supply cow dung to the digester • It is made at the ground level so that the cow dung can be poured easily. • made up of bricks, cement and sand. • The outlet wall of the inlet chamber is made inclined so that the cow dung easily flows to the digester. 03/13/13
Digester • Most important part of biogas plant • Fermentation takes place - fermentation tank. • Built underground – insulated,airtight • Made up of bricks, sand and cement. 03/13/13
• Almost at the middle of the height of digester, two openings are provided on the opposite sides for inflow of fresh cow dung and outflow of used cow dung. 03/13/13
Gas holder • Cylindrical container • Above digester • Collect gas • The gas pipe carries the biogas to the place where it is consumed. 03/13/13
Outlet Chamber • Digested slurry from which the biogas has been generated is removed from the biogas plant. • The outlet chamber is also at the ground level. 03/13/13
03/13/13
Types • GAS HOLDER • Fixed dome type • Floating drum type FREQUENCY OF FILLING SUBSTRATE Batch type Continuous type 03/13/13
Fixed dome type • A fixed-dome plant consists of a digester with a fixed, non-movable gas holder, which sits on top of the digester. 03/13/13
Floating-drum type • Consist of an underground digester and a moving gas-holder. • Gas-holder floats either directly on the fermentation slurry or in a separate water jacket. • The gas is collected in the gas drum, which rises or moves down, according to the amount of gas stored 03/13/13
Floating-drum type 03/13/13
• Batch type • Filled once,sealed. • Emptied when raw materials stop producing gas. • Continuous type • Fed with a definite quantity of wastes at regular intervals • Gas production continuous & regular 03/13/13
03/13/13
MICROBIOLOGY OF BIOGAS •4 steps •Hydrolysis •Acidogenesis •Acetogenesis •Methanogenesis 03/13/13
Hydrolysis • Biomass is made up of large organic polymers • Complex polymers hydrolysed to monomers • complex organic molecules → simple sugars, amino acids, and fatty acids. • Done by hydrolytic fermentative bacteria 03/13/13
Acidogenesis • Results in further breakdown of the remaining components by acidogenic bacteria. • Ammonia, H2, CO2, H2S, shorter volatile fatty acids, carbonic acids, alcohols, as well as trace amounts of other byproducts produced 03/13/13
Acetogenesis • Simple molecules created through the acidogenesis phase further digested to acetic acid, carbon dioxide and hydrogen. • Acetogenic bacteria 03/13/13
Methanogenesis • The terminal stage • Intermediate products of the preceding stages converted to methane, carbon dioxide, and water. • These components make up the majority of the biogas emitted from the system. • Methanogenic bacteria 03/13/13
MICRO ORGANISMS • Hydrolytic & fermentative bacteria. • Acidogenic bacteria. • Acetogenic bacteria. • Methanogenic bacteria. 03/13/13
03/13/13
Methanogenic bacteria. • Create methane from the final products of acetogenesis as well as from some of the intermediate products from hydrolysis and acidogenesis . • Archaebacteria 03/13/13
MAJOR GENERA OF METHANOGENIC BACTERIA 03/13/13
• Cocci • Spirilli • Bacilli Cocci forming colonies in cubical packets of • sarcina eight or more are called sarcina 03/13/13
• Methanogens are a diverse group of organisms that can live in a wide range of environments. • They have been found in a range of salinity from freshwater to hypersaline. 03/13/13
• Biogas plant – Methanosarcina barkeri, Methanobacterium omelianskii 03/13/13
03/13/13
Factors affecting methane formation. • pH • Temperature • Nitrogen concentration • C:N ratio • Creation of anaerobic conditions 03/13/13
pH • 6-8 • Acidic medium lowers methane formation. • Temperature • Fluctuation ↓ methane formation – inhibit growth of methanogens. • 30-40oC 03/13/13
Nitrogen concentration • ↑ N2 - ↓ growth of bacteria - ↓ CH4 C:N ratio • Micro organisms in a biogas plant needs both N nitrogen and C carbon. • Research has shown that the methanogenic bacteria work best with a C/N ratio 30:1. 03/13/13
Creation of anaerobic conditions • CH4 production takeplace in strictly anaerobic condition. • Digesters – airtight, burried under soil. 03/13/13
03/13/13

More Related Content

Biogas

  • 1. KASHMEERA N.A. IV SEM MSc ZOOLOGY ROLL No: 37 03/13/13
  • 4. Mystery unveiled…. Alessandro volta 03/13/13
  • 5. BIOGAS • Mixture of gases. • Produced by anaerobic digestion of organic matter. • Consist of CH4 ,CO2 ,traces of H2 & other gases. 03/13/13
  • 8. BENEFITS FROM BIOGAS PLANTS • Used mainly for cooking & lighting purposes. • Used in internal combustion engines to power water pumps & electric generators. 03/13/13
  • 9. • Used as fuel in fuel type refridgerators. • Sludge - fertilizer. • ↓ envt. pollution 03/13/13
  • 11. SUBSTRATE • Plant & animal biomass. • Plant biomass – • Animal biomass – cattle dung,manure from poultry,goats & sheep slaughter house & fishery wastes. • Agricultural wastes also used 03/13/13
  • 13. Parts of biogas plant • Digester • Gas holder • Inlet • Outlet 03/13/13
  • 14. Inlet chamber • To supply cow dung to the digester • It is made at the ground level so that the cow dung can be poured easily. • made up of bricks, cement and sand. • The outlet wall of the inlet chamber is made inclined so that the cow dung easily flows to the digester. 03/13/13
  • 15. Digester • Most important part of biogas plant • Fermentation takes place - fermentation tank. • Built underground – insulated,airtight • Made up of bricks, sand and cement. 03/13/13
  • 16. • Almost at the middle of the height of digester, two openings are provided on the opposite sides for inflow of fresh cow dung and outflow of used cow dung. 03/13/13
  • 17. Gas holder • Cylindrical container • Above digester • Collect gas • The gas pipe carries the biogas to the place where it is consumed. 03/13/13
  • 18. Outlet Chamber • Digested slurry from which the biogas has been generated is removed from the biogas plant. • The outlet chamber is also at the ground level. 03/13/13
  • 20. Types • GAS HOLDER • Fixed dome type • Floating drum type FREQUENCY OF FILLING SUBSTRATE Batch type Continuous type 03/13/13
  • 21. Fixed dome type • A fixed-dome plant consists of a digester with a fixed, non-movable gas holder, which sits on top of the digester. 03/13/13
  • 22. Floating-drum type • Consist of an underground digester and a moving gas-holder. • Gas-holder floats either directly on the fermentation slurry or in a separate water jacket. • The gas is collected in the gas drum, which rises or moves down, according to the amount of gas stored 03/13/13
  • 24. • Batch type • Filled once,sealed. • Emptied when raw materials stop producing gas. • Continuous type • Fed with a definite quantity of wastes at regular intervals • Gas production continuous & regular 03/13/13
  • 26. MICROBIOLOGY OF BIOGAS •4 steps •Hydrolysis •Acidogenesis •Acetogenesis •Methanogenesis 03/13/13
  • 27. Hydrolysis • Biomass is made up of large organic polymers • Complex polymers hydrolysed to monomers • complex organic molecules → simple sugars, amino acids, and fatty acids. • Done by hydrolytic fermentative bacteria 03/13/13
  • 28. Acidogenesis • Results in further breakdown of the remaining components by acidogenic bacteria. • Ammonia, H2, CO2, H2S, shorter volatile fatty acids, carbonic acids, alcohols, as well as trace amounts of other byproducts produced 03/13/13
  • 29. Acetogenesis • Simple molecules created through the acidogenesis phase further digested to acetic acid, carbon dioxide and hydrogen. • Acetogenic bacteria 03/13/13
  • 30. Methanogenesis • The terminal stage • Intermediate products of the preceding stages converted to methane, carbon dioxide, and water. • These components make up the majority of the biogas emitted from the system. • Methanogenic bacteria 03/13/13
  • 31. MICRO ORGANISMS • Hydrolytic & fermentative bacteria. • Acidogenic bacteria. • Acetogenic bacteria. • Methanogenic bacteria. 03/13/13
  • 33. Methanogenic bacteria. • Create methane from the final products of acetogenesis as well as from some of the intermediate products from hydrolysis and acidogenesis . • Archaebacteria 03/13/13
  • 34. MAJOR GENERA OF METHANOGENIC BACTERIA 03/13/13
  • 35. • Cocci • Spirilli • Bacilli Cocci forming colonies in cubical packets of • sarcina eight or more are called sarcina 03/13/13
  • 36. • Methanogens are a diverse group of organisms that can live in a wide range of environments. • They have been found in a range of salinity from freshwater to hypersaline. 03/13/13
  • 37. • Biogas plant – Methanosarcina barkeri, Methanobacterium omelianskii 03/13/13
  • 39. Factors affecting methane formation. • pH • Temperature • Nitrogen concentration • C:N ratio • Creation of anaerobic conditions 03/13/13
  • 40. pH • 6-8 • Acidic medium lowers methane formation. • Temperature • Fluctuation ↓ methane formation – inhibit growth of methanogens. • 30-40oC 03/13/13
  • 41. Nitrogen concentration • ↑ N2 - ↓ growth of bacteria - ↓ CH4 C:N ratio • Micro organisms in a biogas plant needs both N nitrogen and C carbon. • Research has shown that the methanogenic bacteria work best with a C/N ratio 30:1. 03/13/13
  • 42. Creation of anaerobic conditions • CH4 production takeplace in strictly anaerobic condition. • Digesters – airtight, burried under soil. 03/13/13