Substitute fuel
Substitute fuels ( RDF ) or secondary fuels (SBS) are fuels that are obtained from waste . This can be solid , liquid or gaseous waste that is processed in different processing depths for the respective purpose.
The waste used to produce substitute fuel can come from households , industry or commerce . The depth of treatment depends on the use of the substitute fuel and the different quality requirements of the thermal process. To date, neither the processing nor the product substitute fuel are legally defined.
The processing steps for the high-calorific fractions from commercial waste and household waste include pre-sorting, coarse shredding, sieve classification, air sifting and ferrous and non-ferrous separation . Additional processing steps for the production of secondary fuels are sensory sorting and drying. In addition to the emission-relevant parameters, important fuel parameters are the calorific value , chlorine content and the ash content . RDF is used together with conventional fuels in what is known as co-incineration, especially in cement, lime, lignite and, for the most part, in industrial power plants (high calorific fraction) as well as in waste incineration plants or as the sole fuel in RDF power plants. In addition to sustainable use, the advisability of using substitute fuels should be assessed by comparing the energy efficiency of the energetic and material recycling.
Definition of terms
The term substitute fuel or secondary fuel includes all non- fossil fuels . They can be produced from selectively obtained, production-specific (commercial) waste as well as from unspecific waste mixtures such as municipal waste.
This includes both liquid, paste, as well as solid waste and biomass, which for the energy recovery / incineration are processed, which endkonfektioniert and heating value are used for energy recovery. These are e.g. B. high calorific fractions from municipal waste, commercial waste, solvents , waste oil , whole or shredded tires and dried sewage sludge , rice husks, straw or even animal meal .
The fraction separated from the waste mixture, which then has a higher calorific value than the initial raw waste, is referred to as the “high calorific value fraction”. It is usually obtained with a lower degree of processing (municipal) and passed on to private processors for post-processing. This high-calorific fraction can also be used without further treatment in so-called substitute fuel power plants, which generate steam or electricity from it.
History and current status
For around 40 years, fuel has been produced from mixed waste from various origins using mechanical processes. The term “BRAM” ( acronym for “fuel from garbage”) developed around 1980 describes the first approaches to fuel production from undefined waste mixtures, the origin and composition of which were completely unknown. However, the use of waste fuels was less successful then than it is today. The term BRAM is no longer in use today, but in a report by the European Commission it was still used in 2003 as the German term for Refuse Derived Fuel (RDF).
Today the terms replacement, substitute or secondary fuel are common. The introduction of these terms is associated with the introduction of qualitative minimum requirements and regulated quality assurance. Quality associations such as the Federal Quality Association for Secondary Fuel e. V. (BGS) founded. In the past, new machine technologies for shredding and sorting waste have been developed. Quality control and quality assurance are made possible by further developed sorting techniques such as optimized eddy current separators for separating non-ferrous metals or new sensor-supported sorting techniques.
Efforts are also being made at the European level to standardize quality requirements. To date, however, neither the processing nor the product substitute fuel are legally defined. According to the EU Waste Framework Directive (2008/98 / EC), energy recovery or the processing of waste into fuels does not constitute recycling . According to the EU Waste Framework Directive (2008/98 / EC), reuse and recycling take precedence over energy recovery, when it is the best option from an environmental point of view. Only if the energy efficiency (energy output / energy input ) is over 60%, in newer systems (approved after December 31, 2008) over 65%, is the waste incineration according to 2008/98 / EC an energetic recovery, otherwise it is a waste disposal .
So far, it has not yet been clearly defined at EU level at which stage substances are no longer considered waste but rather products. A possible CEN standardization of substitute fuels would currently not change the waste status of the material. With an amendment to the EU Waste Framework Directive, EU-wide criteria could be developed in the future, compliance with which the RDF material would be redeclared from a waste to a product.
Processing intensity and quality requirements
The processing intensity depends on the use of the substitute fuel as well as on the different quality requirements of the customers, who provide a clear specification of the product to be accepted. Important fuel parameters also result from the quality of the raw waste used for the production of substitute fuel.
These are calorific value , residue on ignition and chlorine content. Depending on the immission law permits of the plant in which the fuel is used, minimum and maximum values for heavy metal content are defined and various demands are made on the degree of metal removal.
Different requirements are also placed on the grain size: what is important here is the lumpiness, i.e. the limitation of the piece size and bulk density. The type of storage and transport also depends on the way the substitute fuel is used.
The safeguarding and testing of the quality of a substitute fuel have an impact on the selection of the waste material flow or the raw waste used and the process management of its processing.
Processing method
The higher the quality requirements by the buyer of the substitute fuel, the more complex and therefore more costly the waste separation must be carried out.
The waste mixture is processed in different ways depending on the type and composition of the waste. This process often begins with pre-sorting or the selection of contaminants. This is followed by coarse comminution and then sieve classification, as well as, if necessary, magnetic separation and non-ferrous separation for the separation of valuable metals. The enrichment of the high calorific fractions relevant for the substitute fuel takes place on the one hand already during the sieve classification (for example by means of a drum sieve) and furthermore the use of air separators. As a result, plastic films and paper are enriched or flat and airworthy components are discharged in the flow of light materials.
In order to meet the required quality of substitute fuels, further processing steps may be necessary. Fine processing is carried out for use in cement works, for example. Sensory sorting takes place using near-infrared spectroscopy (NIR) and image recognition systems . Harmful chlorine carriers are removed through sensor sorting . Storage stability and calorific value are increased by drying steps . The product produced can also be pelletized to increase transportability.
Classification and standardization
In Germany there are quality marks of the Gütegemeinschaft secondary fuels and recycling wood e. To classify secondary fuel qualities. V. (BGS). These are the RAL-GZ 724 quality mark for secondary fuels from waste with a high calorific value, the RAL-GZ 727 quality mark for determining the biogenic content in secondary fuels according to RAL-GZ 724 and other solid substitute fuels and RAL-GZ 428 for recycled wood. The criteria for the quality of secondary fuels include, for example, the calorific value, water, chlorine and sulfur content.
The standardization committee CEN TC 343 Solid Recovered Fuels (SRF) was founded in 2002. The standards should first be treated as a technical specification. Only then should they apply as a European standard after a validation process. Many draft standards for the classification of Solid Recovered Fuels , i.e. solid substitute fuels, are currently in the approval process. Only a few points, such as a regulation on the density of pellets and briquettes, have already been ratified. The individual standards should come into force between 2010 and 2012.
A report by the European Recovered Fuel Organization (2005) summarizes the basics for the classification of Solid Recovered Fuels (SRF). The calorific value , chlorine and mercury content were determined as key properties for the classification . The calorific value represents the economic value, chlorine the technological restrictions and mercury the ecological pollution or emissions. According to these three parameters, the SRF are divided into 5 quality classes. According to a resolution in 2004, the lowest quality class must also comply with limit values in order to be classified as SRF.
Recovery and buyer of substitute fuels
RDF is used together with conventional fuels in what is known as co - incineration , especially in cement , lime and lignite power plants, largely also in industrial power plants (high calorific fraction) and in waste incineration plants or as the sole fuel in RDF power plants. All over Europe, plants using RDF must at least meet the requirements of the EU Directive (2000/76 / EG) on the incineration and co-incineration of waste. In Germany, the 17th BImSchV applies to waste incineration and co-incineration plants.
For example, the secondary fuels that are specifically processed from selected material flows are mainly used in cement power plants due to the higher quality requirements due to sophisticated processing technologies. With an energy content of around 15% and above, raw waste such as old tires, plastics , industrial and commercial waste as well as animal meal and animal fats are suitable for refuse-derived fuel processing for use in the cement industry. With lower energy shares u. a. waste oil , solvents and municipal waste are also used for processing. Airworthy fractions of secondary fuels are also known as " fluff " and are used in the cement industry.
Energy efficiency
In contrast to thermal treatment, the energetic recovery of waste is the use of the waste, i.e. H. the use of the waste- generated energy content is more in the foreground. Systems that only use waste-derived fuels must, however, unlike co-incineration systems (usually secondary fuel), have a comparable flue gas cleaning system, so that the pollutant potential is also eliminated. The energetic recovery of waste can be assessed in terms of energy efficiency . With regard to the discussion about the advisability of using RDF, the comparison of energy efficiency with energetic and material recycling is relevant.
With the material group paper , cardboard and cardboard (PPK) as well as with some plastics, the material recycling is usually more energy efficient than the energetic. The cumulative energy expenditure for the production of copy paper from cellulose is approx. 35 MJ / kg. With a cumulative energy expenditure for the production of copy paper from waste paper of approx. 15 MJ, approx. 20 MJ / kg are saved in the material recycling. In the case of energetic recovery, on the other hand, only approx. 10 MJ / kg are saved with a high fuel efficiency of 76%.
When producing polyethene polymers from secondary materials, around 53 MJ / kg are saved compared to the use of primary materials. In contrast, the energy saving as RDF is only 32.7 MJ / kg, even assuming a high degree of fuel utilization. The energetic recovery of waste paper and waste plastics makes sense, however, if this z. B. are not suitable for recycling due to soiling or small parts. With regard to bio-waste , the highest energy efficiency is achieved if bio-waste is used as compost and at the same time the straw, which can be replaced by compost on arable land, is used for energy.
literature
- Sabine Flamme, Jochen Bender: Experience in quality assurance of substitute fuels. In: ASA GmbH: MBA Technology - Switching point for material flows and energy efficiency. International 8th ASA Waste Days, February 24, 2010, ISBN 978-3-935974-28-8 , pp. 121-127.
- Dirk Lechtenberg, H. Diller: Alternative Fuels and Raw Materials Handbook for the Cement and Lime Industry, Vol. 1, Düsseldorf, Verlag Bau und Technik 2012; ISBN 978-3-7640-0550-4
- Sabine Flamme, Jochen Bender: How are standardized methods for the analysis of substitute fuels created. In: B. Bilitewski, P. Werner, S. Rotter, G. Hoffmann (Eds.): EBS - Analytik 2 - Quality assurance and input control. 1st edition. Dresden 2009, ISBN 978-3-934253-52-0 , pp. 19-33.
- Sabine Flamme, Jochen Bender: Quality assurance for substitute fuels as a guarantee of success. In: W. Rasemann (Ed.): Proceedings of the 14th Freiberg Sampling Conference. Volume 14, Freiberg 2009, ISBN 978-3-938390-06-1 .
- S. Flamme: ( Page no longer available , search in web archives ) Status of the European standardization for alternative fuels . (PDF; July 2010; 9.2 MB). In: M. Faulstich, AI Urban, B. Bilitewski: 12th symposium on thermal waste treatment. Future in Germany and Europe . (= Series of publications by the Waste Technology Department). University of Gh Kassel, 2007, p. 135 ff.
- K. Fricke, T. Bahr, W. Bidlingmaier, T. Turk: Energy efficiency of the material and energetic recovery of selected waste fractions. In: Garbage and Garbage. Issue 2, year 2010, p. 63 ff.
- B. Gallenkemper: Optimization approaches for secondary fuel and energy supply at MBT . In: K. Fricke, C.-G. Bergs, G. Kosak, R. Wallmann: Energy from waste, biomass and substitute material utilization . 69th Symposium of the ANS e. V. Göttingen, September 16 and 17, 2008, p. 77 ff.
- A. Gendebien, A. Leavens, K. Blackmore, A. Godley, K. Lewin, KJ Whiting, R. Davis, J. Giegrich, H. Fehrenbach, U. Gromke, N. del Bufalo, D. Hogg: Refuse Derived Duel, Current Practice and Perspectives (B4-3040 / 2000/306517 / MAR / E3). (PDF; 891 kB; accessed in April 2011) Final Report 2003. European Commission - Directorate General Environment, Report No .: CO 5087-4
- T. Pretz: Secondary fuel - processing and recycling. In: K. Fricke, C.-G. Bergs, G. Kosak, R. Wallmann: Energy from waste, biomass and substitute material utilization . 69th Symposium of the ANS e. V. Göttingen, September 16 and 17, 2008, p. 167 ff.
- AI Urban, M. Faulstich, B. Bilitewski: Energetic waste recycling in a waste incineration plant from the perspective of science. In: AI Urban, B. Bilitewski, M. Faulstich: 5th symposium on thermal waste treatment. Future in Germany and Europe. October 9-11, 2000 Kassel. (= Series of publications by the Waste Technology Department). University of Gh Kassel, p. 361 ff.
- T. Glorius van Tubergen, E. Waeyenbergh: Classification of Solid Recovered Fuels . ( Memento of February 26, 2016 in the Internet Archive ) (PDF; 434 kB; accessed April 2011) European Recovered Fuel Organization, 2005.
- G. Viersen: Status of the quality assurance of secondary fuels and importance for classic waste incineration. In: J. Grundmann: Alternative fuels. Processing, co-incineration and mono-incineration of solid municipal waste . Springer VDI Verlag, Düsseldorf 2002, p. 83 ff.
- R. Vogt: Ecological assessment of biomass and alternative fuel utilization. In: K. Fricke, C.-G. Bergs, G. Kosak, R. Wallmann: Energy from waste, biomass and substitute material utilization . 69th Symposium of the ANS e. V. Göttingen, September 16 and 17, 2008, p. 273 ff.
- H. Baier: Use of alternative resources in the cement process. In: B. Kummer, R. Brinkmann (Hrsg.): Environmental policy and waste management - A guide for companies, authorities, council members and consumers . TK, Neuruppin 2003, ISBN 3-935317-09-3 , pp. 175-187.
Web links
- Gütegemeinschaft secondary fuel and recycling wood e. V.
- Position of the BUND on "substitute fuel power plants" - Federation for the Environment and Nature Conservation Germany NRW
- Position of the European Environmental Associations Organization for Standardization (ECOS) on the CEN standard for EBS (PDF; 159 kB)
- Model for the preliminary calculation of mechanical-biological residual waste treatment plants for the production of substitute fuels (dissertation on the topic) ( Memento from March 30, 2005 in the Internet Archive ) (PDF; 744 KB)
- Declarations on RDF ( Memento from October 28, 2008 in the Internet Archive ) (English)
Individual evidence
- ↑ A. Gendebien, A. Leavens, K. Blackmore, A. Godley, K. Lewin, KJ Whiting, R. Davis, J. Giegrich, H. Fehrenbach, U. Gromke, N. del Bufalo, D. Hogg: Refuse Derived Duel, Current Practice and Perspectives (B4-3040 / 2000/306517 / MAR / E3). (PDF; 891 kB; accessed in April 2011) - Final Report 2003. European Commission - Directorate General Environment, Report No .: CO 5087-4
- ↑ Karlsruhe Chamber of Commerce and Industry: Amendment of the EU Waste Framework Directive entered into force . ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. July 2010.
- ↑ RAL quality: quality mark (PDF; 3.1 MB) July 2010.
- ↑ European Committee for Standardization: cen / tc 343 - Standards under development ( Memento of August 6, 2010 in the Internet Archive ), July 2010.
- ↑ "In addition, a valuable fuel is produced from commercial waste with high calorific value such as plastics in a so-called fluff system (" airworthy fractions ") that is used in the cement industry and replaces fossil fuels." ( Http: //www.avgkoeln. de / de / fuel production )
- ↑ K. Fricke, T. Bahr, W. Bidlingmaier, T. Turk: Energy efficiency of the material and energetic recovery of selected waste fractions (2010). In: Garbage and Garbage. Year 2010, issue 2, p. 63 ff.
