Refuse-derived fuel

Refuse-derived fuel (RDF) or solid recovered fuel/ specified recovered fuel (SRF) is a fuel produced by shredding municipal solid waste (MSW) or steam pressure treating in an autoclave. RDF consists largely of organic components of municipal waste such as plastics and biodegradable waste. RDF processing facilities are normally located near a source of MSW, while an optional combustion facility is normally close to the processing facility, it may also be located at a remote location. SRF can be distinguished from RDF in the fact that it is produced to reach a standard such as CEN/343

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Processing methods

Noncombustible materials such as glass and metals are removed during the post treatment processing cycle with an air knife or other mechanical separation processing. The residual material can be sold in its processed form (depending on the process treatment) or may be compressed into pellets, bricks, or logs and used for other purposes either stand alone or in a recursive recycling process. ^[1]

Advanced processing RDF methods (pressurised steam treatment in an autoclave) can remove or significantly reduce harmful pollutants and heavy metals for use as a material for a variety of manufacturing and related uses. RDF is extracted from MSW using mechanical heat treatment, mechanical biological treatment or waste autoclaves.

The production of RDF may involve some but not all of the following steps:

• Preliminary liberation (not required for autoclave treatment)
• Size screening (post treatment step for autoclave treatment)
• Magnetic separation (post treatment for autoclave treatment)
• Coarse shredding (not required for autoclave treatment)
• Refining separation

End markets

RDF can be used in a variety of ways to produce electricity. It can be used alongside traditional sources of fuel in coal power plants. RDF can be used in the cement kiln industry, where the strict standards of the Waste Incineration Directive are met. RDF can also be fed into plasma arc gasification modules,pyrolysis plants and where the RDF is capable of being combusted cleanly or in compliance with the Kyoto Protocol, RDF can provide a funding source where unused carbon credits are sold on the open market via a carbon exchange. However the use of municipal waste contracts and the bankability of these solutions is still a relatively new concept thus RDF's financial advantage may be debatable.

Regional use

Iowa

The first full-scale waste-to-energy facility in the US was the Arnold O. Chantland Resource Recovery Plant, built in 1975 located in Ames, Iowa. This plant also produces RDF that is sent to local power plants for fuel.^[2]

Manchester

The city of Manchester, in the north west of England, is in the process of awarding a contract for the use of RDF which will be produced by proposed mechanical biological treatment facilities as part of a huge PFI contract. The Greater Manchester Waste Disposal Authority has recently announced there is significant market interest in initial bids for the use of RDF which is projected to be produced in tonnages up to 900,000 tonnes per annum.^[3][4]

See also

• Biodrying
• Cement kiln
• Mechanical biological treatment
• Mechanical heat treatment

References

1. ^ Williams, P. (1998) Waste Treatment and Disposal. John Wiley and Sons, Chichester
2. ^ Arnold O. Chantland Resource Recovery Plant, www.city.ames.ia.us, Retrieved 29.11.06
3. ^ Healthy interest for Manchester waste-derived fuel contract, www.letsrecycle.com, Accessed 20.11.06
4. ^ Manchester seeks outlets for refuse-derived fuel, www.letsrecycle.com, Accessed 20.11.06