4. Need for waste to energy
The amount of solid waste generated each year
has been increasing much faster than population
growth.
Growing demand of energy is also increases.
Today, we face numerous environmental &
economic challenges:
•Population growth and associate waste disposal needs
•Global Warming
•Dependence on fossil fuels
There is a common solution for all of these
challenges.
Energy-from-Waste (EfW) provides:
•Safe, economic waste disposal
•Greenhouse gas reduction
•Renewable energy
7. Waste to Energy
Waste-To-Energy (WTE) technologies recover
the energy from the waste. Waste can include:
•Residential
•Industrial
• Commercial
• Institutional
• Construction and demolition
All of the above included as †œmunicipal solid
waste(MSW).
• Agriculture
14. CASE STUDY
European nations rely on waste-to-energy as the
preferred method of waste disposal.
According to the Confederation of European Waste-to-
Energy Plants (CEWEP), Europe currently treats 50
million ton of wastes at waste-to-energy plants each
year, generating an amount of energy that can supply
electricity for 27 million people or heat for 13 million
people
15. TYPES OF ENERGY FROM WASTE
Thermal conversion:
•Combustion
•Gasification
•Pyrolysis
Biochemical conversion
•Anaerobic Digestion
Landfill Gas
16. TECHNOLOGY SELECTION CONSIDERATIONS
ECONOMY
ENVIRONMENT
ENERGY
• CO2 Control
• DXNs Control
• Emission Control
• Landfill Control
• Cost Control
• Profit
• Growth
• Energy Recovery
• High Efficiency
• Utilization / Sale
Waste characteristics
• waste type
• waste quality
• waste contents
18. Thermal Conversion: Gasification
• Gasification is a process that uses high temperatures
(without combustion) to decompose materials to produce
synthetic gas. Temperature > 1300oF
• It takes place in the presence of limited amounts of
oxygen
19. Thermal Conversion: Pyrolysis
• It is defined as the thermal decomposition of carbon-
based materials in an oxygen-deficient atmosphere
using heat to produce syngas.No air or oxygen is
present and no direct burning takes place. The process
is endothermic.
• Lower temperature than gasification (750 – 1500oF)
20. Syngas
Main product of
gasification
and pyrolysis
Caloriific Value:
approx. 13
MJ/kg, half of
natural gas
It is used as a
fuel to
generate
electricity or
steam
It is used to
produce
synthetic diesel
23. Biochemical conversion: Anaerobic Digestion
• “An anaerobic digester is an air tight, oxygen‐free
container that is fed an organic material, such as animal
manure or food scraps.
• A biological process occurs to this mixture to produce
methane gas, commonly known as biogas, along with an
odor‐reduced effluent. Microbes break down manure into
biogas and a nutrient‐rich effluent.”
25. Benefits Of AD
Reduce Environmental Impacts:
• Odors
• Pathogens
• Greenhouse gases
Create value‐added products:
• renewable energy (biogas)
(heat, electricity, CHP, compressed gas for vehicles, pipeline gas)
• fertilizer
• fibers(bedding, mulch, hydroseeding, potting soil amendment)
26. Landfill Gas
• Landfill gas (LFG)-to-energy is a form of anaerobic
digestion and is a biological treatment method of WTE.
• LFG is created during the decomposition of organic
substances in MSW when it is dumped, compacted, and
covered .
27. • LFG-to-energy as a method of WTE conversion does not
require new technology, but instead depends on
harnessing the methane (CH4), carbon dioxide (CO2),
and nitrogen (N2) that is and always has been created
by MSW
• LFG-to-energy is economically attractive because unlike
other WTE conversion technologies, it does not require a
new facility. Gas can be collected from an existing landfill
and either used as is, upgraded to a higher quality gas,
or converted to energy through combustion, a gas
turbine, or a steam turbine
