Podcast
Questions and Answers
What is the primary function of chlorophyll in plants?
What is the primary function of chlorophyll in plants?
What is the approximate percentage of energy used in the world that is accounted for by biomass?
What is the approximate percentage of energy used in the world that is accounted for by biomass?
What is the name of the process by which plants convert solar energy into carbohydrates?
What is the name of the process by which plants convert solar energy into carbohydrates?
What is the gaseous fuel produced from biomass through anaerobic fermentation?
What is the gaseous fuel produced from biomass through anaerobic fermentation?
Signup and view all the answers
What is the range of wavelengths of visible light used by plants for photosynthesis?
What is the range of wavelengths of visible light used by plants for photosynthesis?
Signup and view all the answers
What is the purpose of adding certain portions of digested slurry to the fresh slurry during anaerobic digestion?
What is the purpose of adding certain portions of digested slurry to the fresh slurry during anaerobic digestion?
Signup and view all the answers
What is the ideal pressure range for the proper functioning of the anaerobic digester?
What is the ideal pressure range for the proper functioning of the anaerobic digester?
Signup and view all the answers
What is the primary purpose of energy crops?
What is the primary purpose of energy crops?
Signup and view all the answers
What is the temperature range at which anaerobic bacteria grow and work best?
What is the temperature range at which anaerobic bacteria grow and work best?
Signup and view all the answers
What is the major component of biogas?
What is the major component of biogas?
Signup and view all the answers
What is the term for the process of converting biomass into biogas?
What is the term for the process of converting biomass into biogas?
Signup and view all the answers
What is the primary advantage of anaerobic digestion over other methods of energy production?
What is the primary advantage of anaerobic digestion over other methods of energy production?
Signup and view all the answers
What is the ideal temperature range for anaerobic digestion?
What is the ideal temperature range for anaerobic digestion?
Signup and view all the answers
What is the primary function of hydrolysis in the biochemical process of converting biomass to biogas?
What is the primary function of hydrolysis in the biochemical process of converting biomass to biogas?
Signup and view all the answers
What is the primary advantage of using biomass energy?
What is the primary advantage of using biomass energy?
Signup and view all the answers
What is the optimal temperature range for photosynthesis to occur at its maximum rate?
What is the optimal temperature range for photosynthesis to occur at its maximum rate?
Signup and view all the answers
What is the energy density of charcoal?
What is the energy density of charcoal?
Signup and view all the answers
What is the main component of biogas, produced through anaerobic digestion?
What is the main component of biogas, produced through anaerobic digestion?
Signup and view all the answers
What is the process of converting woody biomass into producer gas?
What is the process of converting woody biomass into producer gas?
Signup and view all the answers
What is biodiesel produced from?
What is biodiesel produced from?
Signup and view all the answers
What is the temperature range in which anaerobic bacteria can digest biomass?
What is the temperature range in which anaerobic bacteria can digest biomass?
Signup and view all the answers
What is one of the methods used to overcome the problem of low temperature in hilly regions for biogas production?
What is one of the methods used to overcome the problem of low temperature in hilly regions for biogas production?
Signup and view all the answers
What is one of the considerations for locating a biogas plant?
What is one of the considerations for locating a biogas plant?
Signup and view all the answers
What is one of the benefits of community biogas plants?
What is one of the benefits of community biogas plants?
Signup and view all the answers
What is one of the suggestions to improve the productivity and efficiency of biogas plants?
What is one of the suggestions to improve the productivity and efficiency of biogas plants?
Signup and view all the answers
What is the ideal solid content of biomass for better digestion?
What is the ideal solid content of biomass for better digestion?
Signup and view all the answers
What is the purpose of seeding in anaerobic digestion?
What is the purpose of seeding in anaerobic digestion?
Signup and view all the answers
What is the effect of faster feeding rate on the digestion process?
What is the effect of faster feeding rate on the digestion process?
Signup and view all the answers
What is the classification of biogas plants based on their operation?
What is the classification of biogas plants based on their operation?
Signup and view all the answers
What is the purpose of mixing and stirring in the digester?
What is the purpose of mixing and stirring in the digester?
Signup and view all the answers
What is the purpose of pyrolysis in biomass conversion?
What is the purpose of pyrolysis in biomass conversion?
Signup and view all the answers
What is the product obtained by catalytic liquefaction process at low temperature and high pressure?
What is the product obtained by catalytic liquefaction process at low temperature and high pressure?
Signup and view all the answers
What is the purpose of gasification in biomass conversion?
What is the purpose of gasification in biomass conversion?
Signup and view all the answers
What is the purpose of leachate collection system in landfilling?
What is the purpose of leachate collection system in landfilling?
Signup and view all the answers
What is the ideal moisture content of garbage for biogas production in landfilling?
What is the ideal moisture content of garbage for biogas production in landfilling?
Signup and view all the answers
What is the purpose of the partition wall in the digester chamber of a floating drum type biogas plant?
What is the purpose of the partition wall in the digester chamber of a floating drum type biogas plant?
Signup and view all the answers
What is the advantage of using a displacement tank in a modified fixed dome type biogas plant?
What is the advantage of using a displacement tank in a modified fixed dome type biogas plant?
Signup and view all the answers
What is the calorific value of biogas?
What is the calorific value of biogas?
Signup and view all the answers
Why can't biogas be used alone in an IC engine?
Why can't biogas be used alone in an IC engine?
Signup and view all the answers
What is the stoichiometric air-fuel ratio of biogas?
What is the stoichiometric air-fuel ratio of biogas?
Signup and view all the answers
Study Notes
Biomass Energy Resources
- Biomass is organic material that can be converted into energy through combustion or metabolic processes
- Main sources of biomass energy: wood, agricultural waste, urban waste, and forest waste
Photosynthesis
- Process by which plants convert solar energy into chemical energy (carbohydrates)
- Requires chlorophyll, carbon dioxide, and water
- Plants absorb red and blue light, but not green light, which is why they appear green
- Biomass production efficiency: 28% of used energy is converted into carbohydrates
Conditions for Photosynthesis
- Temperature: 20-30°C for maximum rate
- Carbon dioxide concentration: increases photosynthesis
- Oxygen concentration: reduces photosynthesis
- Water: increases photosynthesis
- Intensity and wavelength of solar radiation: increases photosynthesis with PAR (photo synthetically active radiation)
Biomass
- Can be used in its original form or transformed into solid, liquid, or gaseous fuels
- Examples of biomass fuels: fuel wood, charcoal, fuel pellets, bioethanol, biogas, producer gas, and biodiesel
Biofuels
- Fuel wood: most common source of biomass energy, energy density of 16-20 MJ/kg
- Charcoal: obtained from wood, energy density of 30 MJ/kg
- Fuel pellets: formed from crop residues, energy density of 16-20 MJ/kg
- Bioethanol: derived from sugarcane, starch, or cellulose, energy density of 26.9 MJ/kg
- Biogas: gaseous fuel produced from biomass, energy density of 23 MJ/m3
Biomass Resources
- Forests: source of fuel wood, charcoal, and producer gas
- Agricultural residues: straw, rice husk, groundnut shell, coconut shell, and sugarcane bagasse
- Energy crops: sugar plants, starch plants, and oil-producing plants
- Urban waste: garbage, sewage, and liquid waste
- Aquatic plants: water hyacinth, seaweed, algae, and kelp
Advantages and Disadvantages of Biomass Energy
- Advantages: renewable, storable, waste management, indigenous, economic development, sanitation, and fertilizers
- Disadvantages: low energy density, labor-intensive, and large land area required
Biogas
- Gaseous fuel produced from biomass through anaerobic digestion
- Composition: 50-60% methane, 25-35% carbon dioxide, and 5% hydrogen and other gases
- Energy density: 23 MJ/m3
- Uses: cooking, heating, lighting, and running small IC engines
Anaerobic and Aerobic Processes
- Anaerobic: process occurring in absence of oxygen, used in biogas production
- Aerobic: process occurring in presence of oxygen
Anaerobic Digestion
- Process of biogas production from biomass slurry
- Factors favoring digestion: wetness, warmness, and darkness
- Three stages: hydrolysis, acid formation, and methane formation
- Digester: airtight equipment used for anaerobic digestion
Advantages of Anaerobic Digestion
- Energy production from waste materials
- Fertilizer production
- Waste management
- Improved sanitation and hygiene
- Containment of odors
Raw Materials for Biogas
- Waste: industrial, agricultural, urban, and forest waste
- Cultivated materials: rice, wheat, and cereals
- Harvested materials: agricultural crops and residues
Factors Affecting Biogas Production
-
Temperature: 20-65°C
-
Pressure: 6-10 cm of water column
-
Water: 9-10% solid content
-
pH value: 6-7.5
-
Feeding rate: uniform feeding rate
-
Presence of nutrients: carbon, nitrogen, and other nutrients
-
Seeding: adding digested slurry to fresh feed
-
Mixing and stirring: mixing of biomass slurry
-
Retention time: 50-60 days
-
Toxic substances: presence of pesticides, detergents, and ammonia
-
Type of biomass: cow dung, poultry manure, etc.### Advantages and Disadvantages of Fixed Drum Type Biogas Plant
-
Lower cost
-
No corrosion problem
-
Better heat insulation
-
No maintenance required
Disadvantages of Fixed Drum Type Biogas Plant
- Gas production per cubic meter of the digester is less
- Variable pressure of biogas
- More risk of leakage due to higher pressure of gas
- More risk of explosion
- Complex installation
Properties of Biogas
- Composition: 60% methane, 40% carbon dioxide, and traces of hydrogen, hydrogen sulphide, and other gases
- Calorific value: 5,600 kcal/m3 or 4,250 kcal/kg
- Stoichiometric air-fuel ratio: 5.27 by volume
- Calorific value of mixture: 767 kcal/m3, equivalent to 85% of gasoline
Application of Biogas in IC Engine
- Biogas cannot be used in IC engine without modification
- Blending biogas with petrol and diesel can run IC engine with small modification
- A mixture of biogas and gasoline containing 5-10% biogas can be used as IC engine fuel, reducing gasoline consumption by 5-10% and fuel cost
Models of Biogas Plants
- Common circular digester with floating gas holder without water seal (KVIC design, India)
- Common circular fixed dome digester (China)
- Flexible gas type combined digester and gas holder
- Taper digester with floating gas holder (Nepal)
- Two-chamber rectangular digester with floating gas holder and water seal (Philippines)
- Jet digester with separate gas holder (Thailand)
- KVIC model
- PRAD model
- ASTRA model
- Ganesh model
Biogas Plant in Hilly Area
- Average temperature remains below 15°C in hilly regions
- Anaerobic bacteria grow and digest biomass in the temperature range of 25-75°C
- Methods to overcome temperature limitations:
- Hot water circulation
- Use of chemicals (e.g., urea and urine)
- Solar energy system
By-Product of Digestion
- By-products of digestion are shown in Figure
Location of Biogas Plant
- Considerations for locating a biogas plant:
- Distance from well or spring used for drinking water purposes
- Proximity to biomass generation area
- Availability of water source
- Open and exposed site for better performance
- Proximity to point of gas consumption
Size of Biogas Plant
- Considerations for deciding the size of the plant:
- Waste generation and animal/people population
- Gas requirements
- Volume of digester tank needed
- Size and shape of digestion tank
- Size of floating drum of the digester
Community Biogas Plants
- Advantages of community biogas plants:
- Efficient cooking fuel
- Electricity generation for various purposes
- Suggestions for improving productivity and efficiency:
- Using biogas in dual fuel engine to generate power
- Using hot exhaust to operate biogas plants at higher temperature
- Using additional materials (e.g., water plants with animal waste) to generate biogas
- New methods of biogas generation using bacterial support structures and recycling of spent slurry
Biomass Conversion Technologies
- Basic technologies to convert biomass into:
- Direct energy
- More valuable or convenient products
- Technologies:
- Incineration
- Thermochemical (pyrolysis)
- Biochemical
Incineration
- Burning or combustion of biomass to obtain useful heat
- Heat can be used for:
- Space heating and cooking
- Generating steam in boiler to run turbine with electric generator
Thermochemical (Pyrolysis)
- Conversion of biomass into more valuable and convenient fuels
- Process:
- Heating biomass in absence of air or partial combustion
- Products:
- Gaseous mixture (H2, CO, CO2, CH4, N2)
- Liquid (acetic acid, acetone, methanol, oil, and tar)
- Pure carbon char
Biomass Gasification
- Conversion of solid biomass into combustible gas mixture (carbon monoxide and hydrogen)
- Process:
- Partial combustion of biomass in absence of sufficient air
- Types of gasifiers:
- Fixed bed updraft gasifier
- Fixed bed down draft gasifier
- Cross draft gasifier
- Fluidized bed gasifier
Energy Recovery from Urban Waste by Landfill Reactors
- Municipal solid waste (MSW) disposal by controlled sanitary landfilling
- Biodegradable urban wastes are segregated and compacted to generate biogas
- Preparing the landfill site:
- Lining with plastic liner and clay to prevent groundwater contamination
- Leachate collection system to collect and recycle leachate
- Optimum moisture content of garbage: 60%
- Biogas production using anaerobic bacteria
- Temperature rises to 60°C during digestion
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the use of biomass energy, primarily obtained from wood, for cooking and heating purposes, particularly in rural areas.
