Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.
MANUFACTURE OF BIOGAS FROM
AGRICULTURAL WASTES
PRESENTED BY-
SUDIPTA GHOSH
&
PALLAVI JHA
NIT DURGAPUR
PAPER NO.- AISEC/16/...
WHY WE NEED RENEWABLE
ENERGY SOURCES?
Do not lead to emission of greenhouse gases.
Environment friendly
Available in ab...
BIOGAS
Biogas typically refers to a mixture of different gases produced by the
breakdown of organic matter in the absence ...
DIFFERENT SOURCES OF
BIOMASS
ANAEROBIC DIGESTION
Anaerobic digestion is a series of biological processes in which
microorganisms breakdown biodegradabl...
STAGES OF ANAEROBIC
DIGESTION
Carbohydrates
Fats
Proteins
Sugars
Fatty
Acids
Amino
Acids
Carbonic
Acids &
Alcohol
Hydrogen...
SINGLE BATCH AD REACTOR
SYSTEM
The concrete reactor with integrated heating system is loaded with
biowaste and closed, st...
BIOGAS YIELD FROM DIFFERENT
SUBSTRATES
REFERENCE: J ranjhita et al. Production of biogas from flowers and vegetable
wastes...
LIGNOCELLULOSIC BIOMASS
PRETREATMENT
THE MAIN PURPOSE OF PRETREATMENT:
Increase porosity
Destroy lignin shell protecting cellulose and hemicellu...
CHEMICAL PRETREATMENT
ALKALINE PRETREATMENT:
Alkali used are mainly lime and NaOH
Causes swelling of lignocelluloses & p...
CHEMICAL PRETREATMENT
DILUTE ACID PRETREATMENT:
Breaks down hemicellulose, disrupts ether bonds between lignin and
hemice...
CHEMICAL PRETREATMENT
OXIDATIVE PRETREATMENT:
Oxidizing agents used are H2O2, O3, O2 & air
Effectively removes lignin & ...
PHYSICAL PRETREATMENT
MECHANICAL PRETREATMENT:
Carried out by mills which breaks open the cellulose structure & increases...
PHYSICAL PRETREATMENT
THERMAL PRETREATMENT:
Temperature- 125 to 190°C under pressure, time-1 hr
Carried out in pressure ...
COMBINED PRETREATMENT
STEAM EXPLOSION:
Most applied process, low use of chemicals & limited energy
consumption
Demerit: ...
BIOLOGICAL PRETREATMENT
Wood degrading microbes like white, brown & soft rot fungi & bacteria
are used
Modifies the chem...
CONCLUSION
Biogas is being watched with keenest interest as environment-friendly,
alternative energy source instead of pe...
pretreatment methods for manufacture of biogas from agricutural wastes
Prochain SlideShare
Chargement dans…5
×

pretreatment methods for manufacture of biogas from agricutural wastes

716 vues

Publié le

An insight into the various pretreatment methods applied to the raw wastes before the preparation of biogas

Publié dans : Sciences
  • Soyez le premier à commenter

pretreatment methods for manufacture of biogas from agricutural wastes

  1. 1. MANUFACTURE OF BIOGAS FROM AGRICULTURAL WASTES PRESENTED BY- SUDIPTA GHOSH & PALLAVI JHA NIT DURGAPUR PAPER NO.- AISEC/16/T-1/16
  2. 2. WHY WE NEED RENEWABLE ENERGY SOURCES? Do not lead to emission of greenhouse gases. Environment friendly Available in abundant quantity and are free to use
  3. 3. BIOGAS Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas is primarily methane (CH4): 50-75% and carbon dioxide(CO2): 25- 50% and may have small amounts of hydrogen sulphide (H2S), H2, O2, N2. BIOGAS UTILIZATION Domestic & Industrial Fuel Automobile Fuel Fuel Cells for Electricity Generation Production of various chemicals like methanol
  4. 4. DIFFERENT SOURCES OF BIOMASS
  5. 5. ANAEROBIC DIGESTION Anaerobic digestion is a series of biological processes in which microorganisms breakdown biodegradable materials in the absence of oxygen to produce biogas. OPTIMUM CONDITIONS FOR AD Absence of Oxygen Temperature: Mesophilic Range- 20 to 45°C pH: 6.4 to 7.2 Carbon to Nitrogen Ratio(C:N) : 20-30 RetentionTime: 15 to 30 days Slow Mixing
  6. 6. STAGES OF ANAEROBIC DIGESTION Carbohydrates Fats Proteins Sugars Fatty Acids Amino Acids Carbonic Acids & Alcohol Hydrogen Carbon dioxide ammonia Methane Carbon dioxide Hydrogen Acetic Acid Carbon dioxide Hydrolysis Acidogenesis Acetogenesis Methanogenesis
  7. 7. SINGLE BATCH AD REACTOR SYSTEM The concrete reactor with integrated heating system is loaded with biowaste and closed, starting the anaerobic degradation.  High organic content leachate is produced The leachate is stored, heated and continuously redistributed in the reactor to increase the biogas yield. The waste is kept in the reactor from 20 to 40 days, until the biogas production stops or drops
  8. 8. BIOGAS YIELD FROM DIFFERENT SUBSTRATES REFERENCE: J ranjhita et al. Production of biogas from flowers and vegetable wastes using anaerobic digestion, International Journal of Research in Engineering &Technology
  9. 9. LIGNOCELLULOSIC BIOMASS
  10. 10. PRETREATMENT THE MAIN PURPOSE OF PRETREATMENT: Increase porosity Destroy lignin shell protecting cellulose and hemicellulose Decrease crystallinity of cellulose Must break the shell for enzyme to access substrate(sugar) PRETREATMENT METHODS: Chemical Physical Biological
  11. 11. CHEMICAL PRETREATMENT ALKALINE PRETREATMENT: Alkali used are mainly lime and NaOH Causes swelling of lignocelluloses & partial lignin solubilization Process Conditions- relatively mild, long reaction time High Cost of Chemicals REFERENCE: MohsenTaherdanak & Hamid Zilouei, Improving biogas production from wheat plant using alkaline pretreatment, Elsevier
  12. 12. CHEMICAL PRETREATMENT DILUTE ACID PRETREATMENT: Breaks down hemicellulose, disrupts ether bonds between lignin and hemicellulose & increases p0rosity of cell wall Typical conditions: Acid used: Dilute H2SO4 Concentration: low(<2%, w/w) Temp: 160-200°C Demerits: i) Removal of lignin is insignificant(<70%) ii) Corrosive to the metal of the reactor iii) Forms furfural & HMF which is inhibitory to fermentation
  13. 13. CHEMICAL PRETREATMENT OXIDATIVE PRETREATMENT: Oxidizing agents used are H2O2, O3, O2 & air Effectively removes lignin & does not produce toxic residues Ozonolysis occurs at room temperature & pressure Expensive ORGANOSOLV PROCESS: Uses organic solvents like ethanol, acetone, carboxylic acid etc. Temp: 200°C, high pressure Removes lignin, hydrolyses hemicellulose Increased risk of combustion & explosion in case of use of flammable organic solvent Solvent recovery is difficult
  14. 14. PHYSICAL PRETREATMENT MECHANICAL PRETREATMENT: Carried out by mills which breaks open the cellulose structure & increases the specific surface area of the biomass Mills divided into hammer or knife mills Greater possibility for enzyme attack Particle size- 1 to 2 mm(effective hydrolysis) Repair cost of mills is large The figure above shows that knife milling slices the fibers & hammer milling grinds the fibers
  15. 15. PHYSICAL PRETREATMENT THERMAL PRETREATMENT: Temperature- 125 to 190°C under pressure, time-1 hr Carried out in pressure cooker, autoclave or microwave heater Water is added to the dry substrate. Presence of heat & H2O disrupts H2 bonds that holds together the cellulose & lignocellulose complex Effective for crops upto 190°C Large scale application –TDH developed at ATZ Entwicklungszentrum in Germany, increase in biogas yield by 20-30%
  16. 16. COMBINED PRETREATMENT STEAM EXPLOSION: Most applied process, low use of chemicals & limited energy consumption Demerit: Long retention time & high temperature can decrease CH4 yield REACTOR FILLEDWITH BIOMASS T=160-260°C High Pressure Sat. Steam Sudden pressure reduction Hemicellulose degradation & lignin matrix disruption
  17. 17. BIOLOGICAL PRETREATMENT Wood degrading microbes like white, brown & soft rot fungi & bacteria are used Modifies the chemical composition & structure of the lignocellulosic biomass. The modified biomass is more amenable to enzyme digestion ADVANTAGES: •No chemical requirement •Low energy input •Mild environmental Conditions •Environment friendly working manner DISADVANTAGES: •Slow •Requires careful control of growth conditions •Large space requirements
  18. 18. CONCLUSION Biogas is being watched with keenest interest as environment-friendly, alternative energy source instead of petroleum. The major shortcoming is the presence of H2S in biogas which can be overcome by biogas cleanup process like biological desulphurization and biofiltration. It is not possible to define the best pretreatment method as it depends on many factors such as type of lignocellulosic biomass and desired products. Research has shown that it is possible to increase the methane yield by over 1,000 % and therefore, cost effective commercial application is possible if the correct techniques are applied.

×