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INCINERATION OF PLASTICS AND OTHER WASTES

INTRODUCTION
WASTES DISPOSAL - Significant from old days
Energy recovery from wastes
Land filling - odor, bacteria growth, ground water contamination, some wastes are not biodegradable
INCINERATION - thermal destruction

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Presented By, DUGLUS VARGHEESE
M7A NO: 28
GUIDE: SREEJITH T.V

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WASTE - A PROBLEM
US generates 300 million metric tons of hazardous wastes annually
According to EPA 17% of all chemical wastes generated are hazardous
CMA results reveals 213 million tons of wastes generated by its member companies
Waste conversion to electrical or 0 mechanical energy should be environmentally benign
SOURCES OF WASTES
Increased use of plastics
Dumps of old tires
Improper disposal of house hold wastes
Hazardous wastes often find their way into storm water and fresh water collection systems
Recycling is highly sensitive to contamination
DISPOSAL OF WASTES
Land fills ” poor method . INCINERATION
* 4 stages ” Drying, Pyrolysis, Gasification
and Combustion
* A type of furnace ” burns wastes at a controlled temperature and controlled
supply of air
* Gases become so hot ; they breakdown in to smaller components ; combine with oxygen to form less harmful gases and steam
AN INCINERATION PLANT
LOW TEMPERATURE OXYGEN ENRICHED SYSTEM
* Non-combustibles are removed prior to
combustion of wastes
* Low operational temperature ” 800 to
850°C
* Low NOx emission
* Low thermal destruction efficiency
LOW TEMPERATURE STARVED AIR
SYSTEM ^ ^ ' .
* Larger residence time
* Larger size
* 2 stages ” 1. pyrolysis 2.
combustion * High initial cost
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PYROLYSIS
* Controlled thermal decomposition in an oxygen free environment
* Efficient to decompose cellulose,
plastics, rubber etc.
* Materials decompose in to Pyro-gas,
Pyro-oil and solid by-products
GASIFICATION
* Thermo-chemical process
* 4 Zones ” Drying zone, Pyrolysis zone,
Combustion zone, Reduction zone
* Drying zone drive off moisture
* Pyrolysis zone
* Temperature of 400°C
* Remaining will be carbon in the form of charcoal
Combustion zone
* C + 02
* 2H2 + 02 Reduction zone
I0°C
CO.
* CO2 + C _
* If water is injected C + H2O _
* C + 2H2
2CO
CH4
CHALLENGES AND OPPURTUNITIES FOR ENERGY RECOVERY
America everyday disposes 5 million tones of hazardous wastes
Catalytic after burner ” complete combustion
Use of O2 instead of air to achieve higher temperature and reduce effluent gases
Heat generated can be used to produce electricity or for direct heating of rooms
Displaces the need for an equivalent amount of electricity to be generated
Saving release of green house gases like C02 from fossil fuel power stations
A planned district heating system is set up at the SELCHP to heat the buildings
CONCLUSION
Amount of waste generated will grow continuously in this millennium
Utilization of energy from waste can save millions of dollars
Thermal destruction of wastes to molecular level allows one to more cleanly convert it in to usable energy
Opportunities for combustion engineers
THANK YOU