Waste-to-energy
Published: September 2, 2008, 6:09 pm
Updated: September 2, 2008, 6:09 pm
This article has been reviewed by the following Topic Editors:
Cutler J. Cleveland,
Rosemarie Szostak
Municipal Waste Combustor
Waste-to-energy is the process in which waste is used to generate useful energy –electricity, heat or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory combustion conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per kilogram. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery boiler to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families.
Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of methane, a high-fuel value gas.
Further reading
Waste to Energy systems, Integrated Waste Services Association
Are you absolutely sure you want to delete this article? This process cannot be undone and is permanent.
Yes, Delete This Article
Are you absolutely sure you want to remove this article? This process cannot be undone and is permanent.
Yes, Remove This Article
Citation
Stefano Consonni (Lead Author);Avanish K Panikkar (Contributing Author);Cutler J. Cleveland, Rosemarie Szostak (Topic Editor) "Waste-to-energy". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth September 2, 2008; Last revised Date September 2, 2008; Retrieved May 22, 2013 <http://www.eoearth.org/article/Waste-to-energy>
The Author
Stefano Consonni graduated in Mechanical Engineering at Politecnico di Milano (Polytechnic of Milan) in 1983 and received a M.S. (1987) and Ph.D. (1992) in Mechanical Engineering at Princeton University. He is professor of Energy Systems at Politecnico di Milano in Italy; from 1998 to 2005 Consonni has acted as head of the campus in the city of Piacenza. Since 2005 he is President of LEAP (Laboratory for Energy and the Environment in Piacenza), a consortium promoted by Politecnico di Milano for ... (Full Bio)
Municipal Waste Combustor
Waste-to-energy is the process in which waste is used to generate useful energy –electricity, heat or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory combustion conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per kilogram. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery boiler to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families.
Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of methane, a high-fuel value gas.
Further reading
Waste to Energy systems, Integrated Waste Services Association
Are you absolutely sure you want to delete this article? This process cannot be undone and is permanent.
Yes, Delete This Article
Are you absolutely sure you want to remove this article? This process cannot be undone and is permanent.
Yes, Remove This Article
Site Options
0 Comments
Add Comment