Refuse-derived fuel
Encyclopedia
Refuse-derived fuel or solid recovered fuel/ specified recovered fuel (SRF) is a fuel produced by shredding and dehydrating solid waste (MSW) with a Waste converter
technology. RDF consists largely of combustible components of municipal waste such as plastic
s and biodegradable waste
. RDF processing facilities are normally located near a source of MSW and, 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
ANAS. A comprehensive review is now available on SRF / RDF production, quality standards and thermal recovery, including statistics on European SRF quality.
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 it may be compressed into pellets, bricks or logs and used for other purposes either stand-alone or in a recursive recycling
process.
Advanced RDF processing 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 municipal solid waste
using mechanical heat treatment
, mechanical biological treatment
or waste autoclave
s.
The production of RDF may involve some but not all of the following steps:
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.
Several methods have been developed by the European CEN 343 working group to determine the biomass fraction of RDF/SRF. The initial two methods developed (CEN/TS 15440) were the manual sorting method and the selective dissolution method. Since each method suffered from limitations in properly characterizing the biomass fraction, an alternative method was developed using the principles of radiocarbon dating. A technical review (CEN/TR 15591:2007) outlining the carbon-14 method was published in 2007, and a technical standard of the carbon dating method (CEN/TS 15747:2008) was published in 2008. In the United States, there is already an equivalent carbon-14
method under the standard method ASTM D6866.
Although carbon-14 dating can determine with excellent precision the biomass fraction of RDF/SRF, it cannot determine directly the biomass calorific value. Determining the calorific value is important for green certificate programs such as the Renewable Obligation Certificate program in the United Kingdom. These programs award certificates based on the energy produced from biomass. Several research papers, including the one commissioned by the Renewable Energy Association in the UK, have been published that demonstrate how the carbon-14 result can be used to calculate the biomass calorific value.
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.
, 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.
plant. Municipal solid waste
as well as industrial waste is turned into refuse-derived fuel. The 70,000-80,000 tonnes RDF that is produced per annum is used to power the nearby BFB-plant, which provides the citizens of Borås
with electricity and district heating
.
Waste converter
A waste converter is a machine used for the treatment and recycling of solid and liquid refuse material. A converter is a self-contained system capable of performing the following functions: pasteurization of organic waste; sterilization of pathogenic or biohazard waste; grinding and pulverization...
technology. RDF consists largely of combustible components of municipal waste such as plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s and biodegradable waste
Biodegradable waste
Biodegradable waste is a type of waste, typically originating from plant or animal sources, which may be degraded by other living organisms. Waste that cannot be broken down by other living organisms are called non-biodegradable....
. RDF processing facilities are normally located near a source of MSW and, 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
ANAS. A comprehensive review is now available on SRF / RDF production, quality standards and thermal recovery, including statistics on European SRF quality.
Processing methods
Non-combustible materials such as glassGlass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
and metals are removed during the post-treatment processing cycle with an air knife
Air knife
An air knife is a tool used to blow off liquid or debris from products as they travel on conveyors. Air knives are normally used in manufacturing or as the first step in a recursive recycling process to separate lighter or smaller particles from other components for use in later or subsequent...
or other mechanical separation processing. The residual material can be sold in its processed form (depending on the process treatment) or it may be compressed into pellets, bricks or logs and used for other purposes either stand-alone or in a recursive recycling
Recursive recycling
Recursive Recycling is a technique where a function, in order to accomplish a task, calls itself with some part of the task or output from a previous step...
process.
Advanced RDF processing 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
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
and related uses. RDF is extracted from municipal solid waste
Municipal solid waste
Municipal solid waste , commonly known as trash or garbage , refuse or rubbish is a waste type consisting of everyday items we consume and discard. It predominantly includes food wastes, yard wastes, containers and product packaging, and other miscellaneous inorganic wastes from residential,...
using mechanical heat treatment
Mechanical heat treatment
Mechanical heat treatment is an alternative waste treatment technology. This technology is also commonly termed Autoclaving. MHT involves a mechanical sorting or pre-processing stage with technology often found in a material recovery facility. The mechanical sorting stage is followed by a form of...
, mechanical biological treatment
Mechanical biological treatment
A mechanical biological treatment system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion...
or waste autoclave
Waste autoclave
A waste autoclave is a form of solid waste treatment that utilises heat, steam and pressure of an industrial autoclave in the processing of waste. Waste autoclaves process waste either in batches or in continuous-flow processes. In batch processes, saturated steam is pumped into the autoclave at...
s.
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. In Europe RDF can be used in the cement kiln industry, where the strict standards of the Waste Incineration DirectiveWaste Incineration Directive
The Waste Incineration Directive, more formally Directive 2000/76/EC of the European Parliament and of the Councilof 4 December 2000 on the incineration of waste , is a Directive issued by the European Union and relates to standards and methodologies required by Europe for the practice and...
are met. RDF can also be fed into plasma arc gasification modules, pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
plants and where the RDF is capable of being combusted cleanly or in compliance with the Kyoto Protocol
Kyoto Protocol
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change , aimed at fighting global warming...
, 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.
Measurement of the biomass fraction of RDF and SRF
The biomass fraction of RDF and SRF has a monetary value under multiple greenhouse gas protocols, such as the European Union Emissions Trading Scheme and the Renewable Obligation Certificate program in the United Kingdom. Biomass is considered to be carbon-neutral since the liberated from the combustion of biomass is recycled in plants. The combusted biomass fraction of RDF/SRF is used by stationary combustion operators to reduce their overall reported emissions.Several methods have been developed by the European CEN 343 working group to determine the biomass fraction of RDF/SRF. The initial two methods developed (CEN/TS 15440) were the manual sorting method and the selective dissolution method. Since each method suffered from limitations in properly characterizing the biomass fraction, an alternative method was developed using the principles of radiocarbon dating. A technical review (CEN/TR 15591:2007) outlining the carbon-14 method was published in 2007, and a technical standard of the carbon dating method (CEN/TS 15747:2008) was published in 2008. In the United States, there is already an equivalent carbon-14
Carbon-14
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues , to date archaeological, geological, and hydrogeological...
method under the standard method ASTM D6866.
Although carbon-14 dating can determine with excellent precision the biomass fraction of RDF/SRF, it cannot determine directly the biomass calorific value. Determining the calorific value is important for green certificate programs such as the Renewable Obligation Certificate program in the United Kingdom. These programs award certificates based on the energy produced from biomass. Several research papers, including the one commissioned by the Renewable Energy Association in the UK, have been published that demonstrate how the carbon-14 result can be used to calculate the biomass calorific value.
Iowa
The first full-scale waste-to-energyWaste-to-energy
Waste-to-energy or energy-from-waste is the process of creating energy in the form of electricity or heat from the incineration of waste source. WtE is a form of energy recovery...
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.
Manchester
The city of ManchesterManchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...
, 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
Mechanical biological treatment
A mechanical biological treatment system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion...
facilities as part of a huge PFI
Private Finance Initiative
The private finance initiative is a way of creating "public–private partnerships" by funding public infrastructure projects with private capital...
contract. The Greater Manchester Waste Disposal Authority
Greater Manchester Waste Disposal Authority
The Greater Manchester Waste Disposal Authority is a waste disposal authority created under the Local Government Act 1985 to carry out the waste management functions and duties of the Greater Manchester County Council after its abolition in 1986....
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.
Bollnäs
During spring 2008 Bollnäs Ovanåkers Renhållnings AB (BORAB) in Sweden, started their new waste-to-energyWaste-to-energy
Waste-to-energy or energy-from-waste is the process of creating energy in the form of electricity or heat from the incineration of waste source. WtE is a form of energy recovery...
plant. Municipal solid waste
Municipal solid waste
Municipal solid waste , commonly known as trash or garbage , refuse or rubbish is a waste type consisting of everyday items we consume and discard. It predominantly includes food wastes, yard wastes, containers and product packaging, and other miscellaneous inorganic wastes from residential,...
as well as industrial waste is turned into refuse-derived fuel. The 70,000-80,000 tonnes RDF that is produced per annum is used to power the nearby BFB-plant, which provides the citizens of Borås
Borås
Borås is a locality and the seat of Borås Municipality, Västra Götaland County, Sweden. It had 63,441 inhabitants in 2005.- Geography :Borås is located at the point of two crossing railways, among them the railway between Gothenburg and Kalmar, and is often considered the Swedish city gaining the...
with electricity and district heating
District heating
District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
.
See also
- BiodryingBiodryingBiodrying is the process by which biodegradable waste is rapidly heated through initial stages of composting to remove moisture from a waste stream and hence reduce its overall weight....
- Cement kilnCement kilnCement kilns are used for the pyroprocessing stage of manufacture of Portland and other types of hydraulic cement, in which calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium silicates...
- Isle of Wight gasification facilityIsle of Wight gasification facilityThe Isle of Wight gasification facility is a municipal waste treatment plant in southern England. It entered the commissioning phase in autumn 2008...
- Mechanical biological treatmentMechanical biological treatmentA mechanical biological treatment system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion...
- Mechanical heat treatmentMechanical heat treatmentMechanical heat treatment is an alternative waste treatment technology. This technology is also commonly termed Autoclaving. MHT involves a mechanical sorting or pre-processing stage with technology often found in a material recovery facility. The mechanical sorting stage is followed by a form of...
- Waste-to-energyWaste-to-energyWaste-to-energy or energy-from-waste is the process of creating energy in the form of electricity or heat from the incineration of waste source. WtE is a form of energy recovery...