prop · GM03141 · 1999-01-01 00:00:00 — (b) För nya spisar: Tillämpa produktstandarder enligt CEN-standarden i utdraget ovan (och motsvarande produktstandarder i och ). I de allmänna åtgärderna för minskning av PAH-utsläpp ingår åtgärder som innefattar utveckling av centrala system för hushåll samt energibesparing, t.ex. förbättrad värmeisolering, som minskar energiförbrukningen. Informationen sammanfattas i tabell 8. Tabell 8: Kontroll av PAH-utsläpp för förbränningsanläggningar i hushåll Hanteringsalternativ Utsläpps- nivå (%)a/ Uppskattad kostnad Hanteringsrisker Använda torkat kol och ved (ved anses torr när den lagrats i åtminstone ). Använda torkat kol. Konstruera värmesystem för fasta bränslen som ger optimerade totala förbränningsförhållanden: - Förgasningszon. - Förbränningszon i keramik. - Effektiv konvektionszon. 55 Medium Det är nödvändigt att förhandla med spistillverkare om att införa ett system för godkännande av spisar. Tekniska instruktioner för effektiv drift. 30 - 40 Låg Kan även åstadkommas med kraftfulla åtgärder för utbildning av allmänheten, i kombination med praktiska instruktioner och typreglering av spisar. Program för att informera allmänheten om korrekt användning av vedeldade spisar. a/ Resterande utsläpp jämfört med före reducering. Träimpregnering med PAH-haltiga koltjäreprodukter kan vara en stor källa till PAH- utsläpp i luften. Utsläpp kan ske under impregneringsprocessen och vid lagring, hantering och användning av impregnerat trä i fria luften. Den mest använda PAH-haltiga koltjäreprodukten är karbolineum och kreosot. Båda är koltjäredestillat som innehåller PAH som skyddsmedel mot biologiska angrepp på timmer och trä. PAH-utsläpp från träimpregneringsanläggningar och lager för impregnerat trä kan minskas med flera olika tekniska lösningar som kan tillämpas antingen separat eller i kombination, t.ex.: (a) Krav på förvaringsplatser som hindrar förorening av jord och ytvatten genom PAH-urlakning och förorenat regnvatten (t.ex. regnskyddade lagerplatser, skyddstak, recirkulering av förorenat vatten från impregneringsprocessen, kvalitetskrav för produkten). (b) Åtgärder som minskar atmosfäriska utsläpp vid impregneringsanläggningar (t.ex. att kyla det varma virket från 90 C till 30 C åtminstone före transport till lagerplatsen. Den alternativa metoden att impregnera trä med kreosot under högtrycksånga i vakuum är att rekommendera som bästa tillgängliga teknik). (c) Optimal mängd upptaget skyddsmedel i virket ger den behandlade produkten tillräcklig motståndskraft på användningsplatsen och kan därför betraktas som en bästa tillgängliga teknik, eftersom behovet av att ersätta materialet minskar. Detta bidrar indirekt till att minska utsläppen från impregneringsanläggningar. (d) Använda träimpregneringsprodukter som innehåller mindre av de PAH som är långlivade organiska föroreningar (POP): - Möjligen använda modifierad kreosot som är en destillationsfraktion som kokar mellan 270 C och 355 C, vilket minskar utsläppen av både flyktiga PAH och tyngre, giftigare PAH. - Avråda från att använda karbolineum, eftersom karbolineumanvändning ökar PAH-utsläppen. (e) Utvärdera, och därefter där så är lämpligt, använda alternativa produkter (t.ex. de som nämns i tabell 9) som minskar beroendet av PAH-baserade produkter. Förbränning av impregnerat trä orsakar utsläpp av PAH och andra skadliga ämnen. Impregnerat trä bör brännas endast i anläggningar som har för ändamålet tillräcklig utsläppsbegränsande åtgärd. Tabell 9: Möjliga alternativ till PAH-baserade produkter Hanteringsalternativ Hanteringsrisker Använda alternativa material i konstruktioner: Andra miljömässiga problem måste utvärderas, t.ex.: - Hållbara hårda träslag (åkanter, staket, grindar). - Tillgång på lämpligt producerat trä. - Plast (trädgårdsartiklar). - Utsläpp som orsakas av tillverkning och destruering av plaster, speciellt PVC-plaster. - Betong (järnvägssliper). - Ersätta artificiella konstruktioner med naturliga (t.ex. åkanter, staket etc). - Använda obehandlat trä. Flera alternativa träimpregneringsmetoder som inte innefattar impregnering med PAH- baserade produkter är under utveckling. AVAILABLE TECHNIQUES TO CONTROL EMISSIONS OF PERSISTENT ORGANIC POLLUTANTS FROM MAJOR STATIONAER SOURCES The purpose of this annex is to provide the Parties to the Convention with guidance in identifying best available techniques to allow them to meet the obligations in article 3, paragraph 5, of the Protocol. "Best available techniques" (BAT) means the most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for emission limit values designed to prevent and, where that is not practicable, generally to reduce emissions and their impact on the environment as a whole: - Techniques'''' includes both the technology used and the way in which the installation is designed, built, maintained, operated and decommissioned; - Available'''' techniques means those developed on a scale which allows implementation in the relevant industrial sector, under economically and technically viable conditions, taking into consideration the costs and advantages, whether or not the techniques are used or produced inside the territory of the Party in question, as long as they are reasonably accessible to the operator; - Best'''' means most effective in achieving a high general level of protection of the environment as a whole. In determining the best available techniques, special consideration should be given, generally or in specific cases, to the factors below, bearing in mind the likely costs and benefits of a measure and the principles of precaution and prevention: - The use of low-waste technology; - The use of less hazardous substances; - The furthering of recovery and recycling of substances generated and used in the process and of waste; - Comparable processes, facilities or methods of operation which have been tried with success on an industrial scale; - Technological advances and changes in scientific knowledge and understanding; - The nature, effects and volume of the emissions concerned; - The commissioning dates for new or existing installations; - The time needed to introduce the best available technique; - The consumption and nature of raw materials (including water) used in the process and its energy efficiency; - The need to prevent or reduce to a minimum the overall impact of the emissions on the environment and the risks to it; - The need to prevent accidents and to minimize their consequences for the environment. The concept of best available techniques is not aimed at the prescription of any specific technique or technology, but at taking into account the technical characteristics of the installation concerned, its geographical location and the local environmental conditions. Information regarding the effectiveness and costs of control measures is based on documents received and reviewed by the Task Force and the on POPs. Unless otherwise indicated, the techniques listed are considered to be well established on the basis of operational experience. Experience with new plants incorporating low-emission techniques, as well as with retrofitting of existing plants, is continuously growing. The regular elaboration and amendment of the annex will therefore be necessary. Best available techniques (BAT) identified for new plants can usually be applied to existing plants provided there is an adequate transition period and they are adapted. The annex lists a number of control measures which span a range of costs and efficiencies. The choice of measures for any particular case will depend on a number of factors, including economic circumstances, technological infrastructure and capacity, and any existing air pollution control measures. The most important emitted from stationary sources are: (a) Polychlorinated dibenzo-p-dioxins/furans (PCDD/F); (b) Hexachlorobenzene (HCB); (c) Polycyclic aromatic hydrocarbons (PAHs). Relevant definitions are provided in annex III to the present Protocol. MAJOR STATIONARY SOURCES OF POP EMISSIONS PCDD/F are emitted from thermal processes involving organic matter and chlorine as a result of incomplete combustion or chemical reactions. Major stationary sources of PCDD/F may be as follows: (a) incineration, including co-incineration; (b) Thermal metallurgical processes, e.g. production of aluminium and other non- ferrous metals, iron and steel; (c) Combustion plants providing energy; (d) Residential combustion; and (e) Specific chemical production processes releasing intermediates and by-products. Major stationary sources of PAH emissions may be as follows: (a) Domestic wood and coal heating; (b) Open fires such as refuse burning, fires and after-crop burning; (c) Coke and anode production; (d) Aluminium production (via Soederberg process); and (e) preservation installations, except for a Party for which this category does not make a significant contribution to its total emissions of PAH (as defined in annex III). Emissions of HCB result from the same type of thermal and chemical processes as those emitting PCDD/F, and HCB is formed by a similar mechanism. Major sources of HCB emissions may be as follows: (a) incineration plants, including co-incineration; (b) Thermal sources of metallurgical industries; and (c) Use of chlorinated fuels in furnace installations. GENERAL APPROACHES TO CONTROLLING EMISSIONS OF POPs There are several approaches to the control or prevention of POP emissions from stationary sources. These include the replacement of relevant feed materials, process modifications (including maintenance and operational control) and retrofitting existing plants. The following list provides a general indication of available measures, which may be implemented either separately or in combination: (a) Replacement of feed materials which are POPs or where there is a direct link between the materials and POP emissions from the source; (b) Best environmental practices such as good housekeeping, preventive maintenance programmes, or process changes such as closed systems (for instance in cokeries or use of inert electrodes for electrolysis); (c) Modification of process design to ensure complete combustion, thus preventing the formation of persistent organic pollutants, through the control of parameters such as incineration temperature or time; (d) Methods for flue-gas cleaning such as thermal or catalytic incineration or oxidation, dust precipitation, adsorption; (e) Treatment of residuals, wastes and sewage sludge by, for example, thermal treatment or rendering them inert. The emission levels given for different measures in tables 1, 2, 4, 5, 6, 8, and 9 are generally case-specific. The figures or ranges give the emission levels as a percentage of the emission limit values using conventional techniques. Cost-efficient considerations may be based on total costs per year per unit of abatement (including capital and operational costs). POP emission reduction costs should also be considered within the framework of the overall process economics, e.g. the impact of control measures and costs of production. Given the many influencing factors, investment and operating cost figures are highly case-specific. CONTROL TECHNIQUES FOR THE REDUCTION OF PCDD/F EMISSIONS incineration includes municipal waste, hazardous waste, waste and sewage sludge incineration. The main control measures for PCDD/F emissions from waste incineration facilities are: (a) Primary measures regarding incinerated wastes; (b) Primary measures regarding process techniques; (c) Measures to control physical parameters of the combustion process and waste gases (e.g. temperature stages, cooling rate, O2 content, etc.); (d) Cleaning of the flue gas; and (e) Treatment of residuals from the cleaning process. The primary measures regarding the incinerated wastes, involving the management of feed material by reducing halogenated substances and replacing them by non-halogenated alternatives, are not appropriate for municipal or hazardous waste incineration. It is more effective to modify the incineration process and install secondary measures for flue-gas cleaning. The management of feed material is a useful primary measure for waste reduction and has the possible added benefit of recycling. This may result in indirect PCDD/F reduction by decreasing the waste amounts to be incinerated. The modification of process techniques to optimize combustion conditions is an important and effective measure for the reduction of PCDD/F emissions (usually 850 C or higher, assessment of oxygen supply depending on the heating value and consistency of the wastes, sufficient time -- 850 C for ca. 2 sec -- and turbulence of the gas, avoidance of cold gas regions in the incinerator, etc.). Fluidized bed incinerators keep a lower temperature than 850 C with adequate emission results. For existing incinerators this would normally involve redesigning and/or replacing a plant -- an option which may not be economically viable in all countries. The carbon content in ashes should be minimized. Flue gas measures. The following measures are possibilities for lowering reasonably effectively the PCDD/F content in the flue gas. The de novo synthesis takes place at about 250 to 450 C. These measures are a prerequisite for further reductions to achieve the desired levels at the end of the pipe: (a) Quenching the flue gases (very effective and relatively inexpensive); (b) Adding inhibitors such as triethanolamine or triethylamine (can reduce oxides of nitrogen as well), but side-reactions have to be considered for safety reasons; (c) Using dust collection systems for temperatures between 800 and 1000 C, e.g. ceramic filters and cyclones; (d) Using low-temperature electric discharge systems; and (e) Avoiding fly ash deposition in the flue gas exhaust system. Methods for cleaning the flue gas are: (a) Conventional dust precipitators for the reduction of particle-bound PCDD/F; (b) Selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR); (c) Adsorption with activated charcoal or coke in fixed or fluidized systems; (d) Different types of adsorption methods and optimized scrubbing systems with mixtures of activated charcoal, open hearth coal, lime and limestone solutions in fixed bed, moving bed and fluidized bed reactors. The collection efficiency for gaseous PCDD/F can be improved with the use of a suitable pre-coat layer of activated coke on the surface of a bag filter; (e) H2O2-oxidation; and (f) Catalytic combustion methods using different types of catalysts (i.e. Pt/Al2O3 or copper-chromite catalysts with different promoters to stabilize the surface area and to reduce ageing of the catalysts). The methods mentioned above are capable of reaching emission levels of 0.1 ng TE/m3 PCDD/F in the flue gas. However, in systems using activated charcoal or coke adsorbers/filters care must be taken to ensure that fugitive carbon dust does not increase PCDD/F emissions downstream. Also, it should be noted that adsorbers and dedusting installations prior to catalysts (SCR technique) yield PCDD/F-laden residues, which need to be reprocessed or require proper disposal. A comparison between the different measures to reduce PCDD/F in flue gas is very complex. The resulting matrix includes a wide range of industrial plants with different capacities and configuration. Cost parameters include the reduction measures for minimizing other pollutants as well, such as heavy metals (particle-bound or not particle- bound). A direct relation for the reduction in PCDD/F emissions alone cannot, therefore, be isolated in most cases. A summary of the available data for the various control measures is given in table 1. Table 1: Comparison of different flue-gas cleaning measures and process modifications in waste incineration plants to reduce PCDD/F emissions Management options Emission Level a/ Estimated costs Management risks Primary measures by modification of feed aterials: - Elimination of precursors and chlorine- containing feed materials; and - Management of waste streams. Resulting emission level not quantified; seems not to be linearly dependent on the amount of the feed material. Pre-sorting of feed material not effective; only parts could be collected; other chlorine-containing material, for instance kitchen salt, paper, etc., cannot be avoided. For hazardous chemical waste this is not desirable. Useful primary measure and feasible in special cases (for instance, waste oils, electrical components, etc.) with the possible added benefit of recycling of the materials. Modification of process Technology: - Optimized combustion conditions; Retrofitting of the whole process needed. - Avoidance of temperatures below 850 C and cold regions in flue gas; - Sufficient oxygen content; control of oxygen input depending on the heating value and consistency of feed material; and - Sufficient time and turbulence. Flue gas measures: Avoiding particle deposition by: Soot cleaners, mechanical rappers, sonic or steam soot . Steam soot blowing can increase PCDD/F formation rates. Dust removal, generally in waste incinerators: < 10 Medium Removal of PCDD/F adsorbed onto particles. Removal methods of particles in hot flue gas streams used only in pilot plants. Fabric filters; 1 - 0.1 Higher Use at temperatures < 150 C. Ceramic filters; Low efficiency Use at temperatures 800- 1000 C. Cyclones; and Low efficiency Medium Use at a temperature of 450 C; promotion of the de novo synthesis of PCDD/F possible, higher NOx emissions, reduction of heat recovery. Use at temperatures of 800- 1000 C. Separate gas phase abatement necessary. High-performance adsorption unit with added activated charcoal particles (electrodynamic venturi). Selective catalytic reduction (SCR). High investment and low operating costs NOx reduction if NH3 is added; high space demand, spent catalysts and residues of activated carbon (AC) or lignite coke (ALC) may be disposed of, catalysts can be reprocessed by manufacturers in most cases, AC and ALC can be combusted under strictly controlled conditions. Different types of wet and dry adsorption methods with mixtures of activated charcoal, open-hearth coke, lime and limestone solutions in fixed bed, moving bed and fluidized bed reactors: Fixed bed reactor, adsorption with activated charcoal or open-hearth coke; and < 2 (0.1 ng TE/m3) High in- vestment, medium operating costs Removal of residuals, high demand of space. Entrained flow or circulating fluidized bed reactor with added activated coke/lime or limestone solutions and subsequent fabric filter. < 10 (0.1 ng TE/m3) Low in- vestment, medium operating costs Removal of residuals. Addition of H2O2. < 2 - 5 (0.1 ng TE/m3) Low in- vestment, low operating costs a/ Remaining emission compared to unreduced mode. waste incinerators may be a major source of PCDD/F in many countries. Specific wastes such as human anatomical parts, infected waste, needles, blood, plasma and cytostatica are treated as a special form of hazardous waste, while other wastes are frequently incinerated on-site in a batch operation. Incinerators operating with batch systems can meet the same requirements for PCDD/F reduction as other waste incinerators. Parties may wish to consider adopting policies to encourage the incineration of municipal and waste in large regional facilities rather than in smaller ones. This approach may make the application of BAT more cost-effective. The treatment of residuals from the flue-gas cleaning process. Unlike incinerator ashes, these residuals contain relatively high concentrations of heavy metals, organic pollutants (including PCDD/F), chlorides and sulphides. Their method of disposal, therefore, has to be well controlled. scrubber systems in particular produce large quantities of acidic, contaminated liquid waste. Some special treatment methods exist. (a) The catalytic treatment of fabric filter dusts under conditions of low temperatures and lack of oxygen; (b) The scrubbing of fabric filter dusts by the 3-R process (extraction of heavy metals by acids and combustion for destruction of organic matter); (c) The vitrification of fabric filter dusts; (d) Further methods of immobilization; and (e) The application of plasma technology. B. Thermal processes in the metallurgical industry Specific processes in the metallurgical industry may be important remaining sources of PCDD/F emissions. (a) Primary iron and steel industry (e.g. blast furnaces, sinter plants, iron pelletizing); (b) Secondary iron and steel industry; and (c) Primary and secondary non-ferrous metal industry (production of copper). PCDD/F emission control measures for the metallurgical industries are summarized in table 2. Metal production and treatment plants with PCDD/F emissions can meet a maximum emission concentration of 0.1 ng TE/m3 (if waste gas volume flow > /h) using control measures. Table 2: Emission reduction of PCDD/F in the metallurgical industry Management options Emission level (%) a/ Estimated costs Management risks Sinter plants Primary measures: - Optimization/encapsulation of sinter conveying belts; Low Not achievable - gas recirculation e.g. emission optimized sintering (EOS) reducing waste gas flow by ca. (reduced costs of further secondary measures by the reduced waste gas flow), cap. 1 million Nm3/h; 40 Low - Electrostatic precipitation + molecular sieve; Medium efficiency Medium - Addition of limestone/activated carbon mixtures; High efficiency (0.1 ng TE/m3) Medium - High-performance scrubbers - existing installation: AIRFINE (Voest Alpine ) since 1993 for 600 000 Nm3/h; second installation planned in the (Hoogoven) for 1998. High efficiency emission reduction to 0.2-0.4 ng TE/m3 Medium 0.1 ng TE/m3 could be reached with higher energy demand; no existing installation Non-ferrous production (e.g. copper) Primary measures: - Pre-sorting of scrap, avoidance of feed material like plastics and PVC-contaminated scrap, stripping of coatings and use of chlorine- free insulating materials; - Quenching the hot waste gases; High efficiency Low - Use of oxygen or of oxygen- enriched air in firing, oxygen injection in the shaft kiln (providing complete combustion and minimization of waste gas volume); 5 - 7 (1.5-2 TE/m3) High - Fixed bed reactor or fluidized jet stream reactor by adsorption with activated charcoal or open-hearth coal dust; (0.1 ng TE/m3) High - Catalytic oxidation; and (0.1 ng TE/m3) High - Reduction of time in the critical region of temperature in the waste gas system. and steel production Primary measures: - Cleaning of the scrap from oil prior to charging of production ; Low Cleaning solvents have to be used. - Elimination of organic tramp materials such as oils, emulsions, greases, paint and plastics from feedstock cleaning; - Lowering of the specific high waste gas volumes; - Separate collection and treatment of emissions from loading and discharging;. - Separate collection and treatment of emissions from loading and discharging; and - Fabric filter in combination with coke injection. Secondary aluminium production Primary measures: - Avoidance of halogenated material (hexachloroethane); - Avoidance of chlorine-containing lubricants (for instance chlorinated paraffins); and - Clean-up and sorting of dirty scrap charges, e.g. by swarf decoating and drying, swim-sink separation techniques and whirling stream deposition; - Single- and multi-stage fabric filter with added activation of limestone/ activated carbon in front of the filter; < 1 (0.1 ng TE/m3) Medium/ high - Minimization and separate removal and purification of differently contaminated waste gas flows; - Avoidance of particulate deposition from the waste gas and promotion of rapid passing of the critical temperature range; and