Abatement techniques

For cleaning colleeted off-gases, various wet and dry systems may be used. Selection of the appropriate technique depends on the composition, flow and conditions of the off-gas stream. The design of the abatement process is critical. Factors such as efficiency, suitability of the method and the input and output loading of the material to be collected are used. A full diseussion of the working principles is given in the BREF document for non-ferrous metal industries. The following techniques are used in the foundry industry. 

For dust and particle removal, both wet and dry systems are used. The main advantage with using dry systems is that the dust is captured dry, which allows its subsequent re-use. Furthermore, no pollution is transferred to another medium, as is the case for wet systems. For gaseous compounds, such as SO2 and chlorides, bag filters are inefficient, since they are not adsorbed onto the filter surface. Experiments with lime injection have not provided good results. The following describes the system used for dust and particle removal  

Cyclones. If the right measures are taken (i.e. heat resistant steel, refractory lining) a cyclone filter may be used for dedusting hot flue-gases (500 - 600 °C). The efficiency is too low to achieve emission levels in the 20 mg/Nm range. The cyclone is mainly used as a spark separator in front of a bag filter. Cyclones are used as a pretreatment step to other abatement systems 

High temperature filter systems (using a ceramic filter medium) These are available on the market but not currently applied in the foundry industry 

Advantages are the capture of water-soluble compounds (such as SO2, chlorides), quick cooling - which prevents dioxin reformation, low investment costs, and less restriction on input temperature. 

---

The Solvent Emissions Directive was adopted in March 1999 by the European Council of Ministers and should be implemented by member states within two years. The adhesives industry uses about 130,000 tonnes of solvents in its products annually and has a key role to play in meeting the Directive s targets. The main impact of emissions reduction will be on adhesives coaters because the adhesive film forms through the evaporation of solvent. For adhesives manufacturers, the main issue is the reduction of fugitive emissions. Both oxidation and recovery are well proven abatement techniques. BELGIUM EUROPEAN COMMUNITY EUROPEAN UNION WESTERN EUROPE... 

Baker, B. K. 1983. The evaluation of unique acid mine drainage abatement techniques. Master s Thesis, West Virginia University, Morgantown, WV. 

Ackenheil Associates Geo Systems, Inc., Evaluation of Pollution Abatement Techniques Applicable to Lost Creek and Brown s Creek Watershed, West Virginia, Appalachian Regional Commission report. National Technical Information Service PB—242—722, October 1973. 

Yaniga PM. 1984. Groundwater abatement techniques for removal of refined hydrocarbons. Houston, TX National Conference and Exhibition on Hazardous Wastes and Environmental Emergencies, March 12-14, 1984, 374-383. 

There are three places noise can be reduced at the source, in the path between the source and personnel, and on the persormel [16]. The ideal place to stop noise is at the source. There are several techniques used in the flare and burner industry to reduce the noise at the source, however, these techniques are limited. Ear protection can reduce noise relative to the personnel using it, unfortunately a plant operator cannot ask a surrounding community or workers within a nearby office building to wear ear protection when the noise levels become a problem. The most common method for reducing noise is in fhe pafh befween the source and personnel using silencers, plenums, and mufflers. The purpose of fhis section is to discuss fhe most common and effective noise abatement techniques utilized in the flare and burner industry. 

As previously discussed, the two main sources of noise emitted from industrial flares is combustion roar and gas jet noise. Inhibiting the rate at which the air and fuel streams mix can reduce the level of combustion roar however, this noise abatement technique generally tends to reduce the smokeless performance, increase thermal radiation, and flame length. Reducing the mixing rate of the air and fuel stream in order to lower combustion roar levels usually cannot justify the accompanying sacrifices in the performance of a flare. 

There are several abatement techniques commonly used to reduce the gas jet noise emitted from flares. Several of these techniques include mufflers, water injection, and modificahons to the nozzle geometry. Mufflers are mosf commonly used on sfeam-assisted flares to abate the high-pressure steam jet noise as shown in the illustration in Figure 8.29. 

VOC Concentration. - Catalytic oxidation is ideally suited to the destruction of low concentrations of VOCs, this is a major advantage for this abatement technique, since it allows low levels of VOC to be combusted which is essential if industry is to comply with current air pollution legislation. 

The applicability of various abatement techniques to differing VOC concentrations is shown in table 1 [1]. Commercially, a catalyst capable of efficiently destroying a wide range of concentrations of VOCs would be preferred, so that legislation concerning their release could be complied with regardless of the actual concentration. However, relatively high concentrations have been used in... 

Abatement techniques using lime compete with processes using other absorbents such as limestone, sodium carbonate/bicarbonate, magnesium hydroxide. 

Although dioxins and furans are destroyed at above 850 °C, they re-form in the temperature range 200 to 450 °C [29.3]. It is understood that, without abatement techniques, municipal incinerators may emit at levels in the range 1 to 10 ng/Nm. Emission limits range from 0.1 to 1 ng/Nm. ... 

Hot curing processes are characterised by major emission problems when heated, the resins and catalysts emit noxious chemicals including ammonia and formaldehyde that can be the source of odour nuisance. A number of abatement techniques have been tried to solve these problems, such as scrubbing, combustion or biological abatement, but none of these has proven to be... 

Abatement techniques Bag house filter for bigger installations Bag house filter for bigger installations Bag house filter for bigger installations Typically not necessary due to small furnace size Not necessary Not necessaiy... 

Various waste and exhaust gas cleaning techniques are used in the foundry industry. Their principles are discussed in the BREF document for non-ferrous metal industries. The properties and emission levels of dust abatement systems are given in Table 3.32. A full discussion on the selection of the abatement technique, its applicability in the various foundry processes and the achievable emission levels is given as part of the techniques to be considered in the selection of BAT in Section 4.5. 

Abatement technique Investment cost (EUR/Nm ) Energy consumption (kW/1000 Nm )... 

Equipment Exhaust gas flow (m /h) Abatement technique Emission level (mg/m )... 

No information was provided concerning techniques for the abatement of VOC-emissions. The lack of information on abatement techniques and associated emission levels made it impossible to formulate a BAT eonclusion. Techniques for the reduction of VOC-emissions related to coating processes (as applied to cores and moulds) may be found in the BREF on Surface Treatment Using Solvents. 

End-of-pipe technique a technique that reduces final emissions or consumptions by some additional process but does not change the fundamental operation of the core process. Synon5mis "secondary technique", "abatement technique". Antonyms "process-integrated technique", "primary technique" (a technique that in some way changes the way in which the core process operates thereby reducing raw emissions or consumptions)... 

In principle, BAT(NEEC) and RACT offer the user flexibility in choosing an emission reduction strategy -choice between a variety of end-of-pipe abatement techniques, low solvent technologies, waste minimisation or any combination of these. It recognises that the most appropriate solution will vary from one application to another with size, product quality required and the age and location of a plant. 

Thermal oxidation as a VOC abatement technique should not be confused with hazardous waste incineration - they have very different purposes and different feed streams. The issues surrounding hazardous waste incineration do not apply to VOC abatement. Thermal oxidation of hydrocarbon and oxygenated solvents is a clean process and converts a hydrocarbon fuel into carbon dioxide, water and recoverable heat. 

The BREF on Common waste gas and waste water treatment/management systems in the chemical sector describes techniques which are commonly applicable to the whole spectrum of the chemical industry. Detailed descriptions of recovery or abatement techniques can be found in the BREF on CWW. 

Hilt, M. B., and I Waslo Evolution of NO Abatement Techniques Through Combustor Design for... 

---