Transcript BIOMASS - Eastern Mediterranean University (EMU), Cyprus

BIOMASS
ABDULAZEEZ MUHAMMAD
118559
ITEC211
CONTENT
• BIOMASS
• WHERE DOES IT COME FROM ?
• TYPES OF BENEFICIAL BIOMASS
• METHODS OF CONVERSION
• ADVANTAGES AND DISADVANTAGES
BIOMASS
Biomass is plant material and animal wastes used to produce
energy.
It is the oldest form of renewable energy known to humans.
WHERE DOES IT COME FROM?
Through the process of photosynthesis, plants
combine carbon dioxide from the air and
water from the ground to produce
carbohydrates (sugars) and oxygen.
Energy is released when the plant is burned.
oxygen from the atmosphere combines with the
carbon in plants to produce carbon dioxide and
water.
The process is cyclic.
TYPES OF BENEFICIAL BIOMASS
• Energy crops
• Crop residues
• Manure
• Urban wastes
TYPES OF BENEFICIAL BIOMASS
• Energy Crops
Energy crops can be grown on farms in potentially
large quantities and in ways that don’t displace or
otherwise reduce food production, such as by
growing them on marginal lands or pastures or as
double crops that fit into rotations with food
crops. Trees and grasses that are native to a region
often require fewer synthetic inputs and pose less
risk of disruption to agro-ecosystems
CROP RESIDUES
• Depending on soils and slope, a certain fraction of
crop residues should be left in the field to
maintain cover against erosion and to recycle
nutrients, but in most cases some fraction of crop
residues can be collected for renewable energy in
a sustainable manner. Food processing also
produces many usable residues.
MANURE
• Manure from livestock and poultry contains
valuable nutrients and, with appropriate
management, should be an integral part of soil
fertility management.
URBAN WASTES
•
People generate biomass wastes in many forms, including
"urban wood waste" (such as tree trimmings, shipping
pallets and clean, untreated leftover construction wood),
the clean, biodegradable portion of garbage (paper that
wouldn’t be recycled, food, yard waste, etc.). In addition,
methane can be captured from landfills or produced in the
operation of sewage treatment plants and used for heat and
power, reducing air pollution and emissions of global
warming gases.
GASIFICATION
• Gasification is a process that converts organic
or fossil based carbonaceous materials into
carbon monoxide, hydrogen and carbon
dioxide. This is achieved by reacting the
material at high temperatures (>700 °C),
without combustion, with a controlled amount
of oxygen and/or steam
PROCESSES OF GASIFICATION
• Drying
• Pyrolysis
• Combustion
• Reduction
PROCESSES OF GASIFICATION
•
DRYING. The biomass is exposed to heat in the gasifier and the
water will boil out, leaving behind dry biomass.
•
PYROLYSIS. When heat is applied to biomass, the volatile
compounds escape and are broken down to simple compounds due to
the heat. This steps leaves behind charcoal, which is due to the very
strong carbon-carbon bonds and the complex structure of the lignin
molecule (lignin being the main protein that gives wood its strength
• COMBUSTION. The complex tars and charcoal are then burned in
the presence of oxygen and turn into water vapors and carbon
dioxide.
•
REDUCTION. This step occurs almost simultaneously to cracking
and combines carbon and oxygen atom to produce carbon monoxide
(CO) and carbon dioxide. The same goes for hydrogen, which is
converted back into water.
METHODS OF CONVERSION
• THERMAL CONVERSION
• BIOCHEMICAL CONVERSION
• CHEMICAL CONVERSION
THERMAL CONVERSION
• Thermal conversion processes use heat as the
dominant mechanism to convert biomass into
another chemical form.
CHEMICAL CONVERSION
• A range of chemical processes may be used to
convert biomass into other forms, such as to
produce a fuel that is more conveniently used,
transported or stored, or to exploit some property
of the process itself.
BIOCHEMICAL
• Biochemical conversion makes use of the
enzymes of bacteria and other microorganisms to
break down biomass. In most cases,
microorganisms are used to perform the
conversion process: anaerobic digestion,
fermentation, and composting.
ADVANTAGES
Utilizing biomass reduces
•Dependence on expensive imported oil
•Net greenhouse gas emissions
•Toxic air emissions
•Air pollution
Agricultural economy is also supported
when biomass is utilized.
ADVANTAGES
Biomass energy can reduce air pollution, provide important wildlife
habitat, reduce soil erosion, and improve soil quality.
Rural economies can become energy self-sufficient by using locally
grown crops to generate electricity for their homes and fuels for their
cars.
DISADVANTAGES
• Biomass is expensive (in terms of producing and
converting it to alcohols).
• There is also difficulty in collecting and storaging
large amounts of biomass for power generation.
• If directly burned particulate matter pollution is a
major concern
• Possible toxic pollution from combustion of
herbicides and pesticides on crop
DISADVANTAGES
• Combustion of biomass products require some
land where they can easily be burnt.
• Consumes more fuel
REFERENCES
•
http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-biomassenergy-works.html#Types_of_Biomass.
•
http://www.nrel.gov/biomass/
•
http://www.conserve-energy-future.com/Advantages_Disadvantages_BiomassEnergy.php