) is a fuel produced from various types of wastes such as Municipal Solid wastes (MSW), industrial wastes or commercial wastes.
The World Business Council for Sustainable Development
provides a definition:
“Selected waste and by-products with recoverable calorific value can be used as fuels in a cement kiln, replacing a portion of conventional fossil fuels, like coal, if they meet strict specifications. Sometimes they can only be used after pre-processing to provide ‘tailor-made’ fuels for the cement process“
RDF consists largely of combustible components of such wastes, as non recycable plastics. paper cardboard, labels, and other corrugative materials. These fractions are separated by different processing steps, such as screening, air classifiation, ballistic separation
, separation of ferrous and non ferrous materials, glass
, stones and other foreign materials and shredding into a uniform grain
size, in order to produce a homogenous material which can be used as substitute for fossil fuels in e.g. cement plants, lime plants, coal fired power plants or as reduction Agent in Steel Furnaces. RDF can be also further specified into e.g. tyre derived fuels (TDF) from used tyres, or solid recovered fuels (SRF).
Others describe the properties, such as
- Secondary fuels
- Substitute fuels
- Solid recovered fuels (SRF)
- “Climafuel®” as trade name from Cemex
- “AF“ as an abbreviation for alternative fuels
- Ultimately most of the designations are only general paraphrases for alternative fuels which are either waste-derived or biomass-derived.
Yet it is the case, that worldwide there is no exact classification
which is used for such materials. Even legislative authorities have not yet established any exact guidelines on the type and composition
of alternative fuels. The first approaches towards classification or specification are to be found in the Federal Republic of Germany (Bundesgütegemeinschaft für Sekundärbrennstoffe) as well as at European level (European Recovered Fuel Organisation). These approaches which are initiated primarily by the producers of alternative fuels, follow a correct approach: Only through a strictly and exactly defined standardisation in the composition of such materials can both production and utilisation be uniform worldwide.
First approaches towards alternative fuel classification:
Solid recovered fuels are part of RDF in the fact that it is produced to reach a standard such as CEN/343 ANAS. A comprehensive review is now available on SRF / RDF production, quality standards and thermal recovery, including statistics on European SRF quality.