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Metal Industries
Published in Charles E. Baukal, Industrial Combustion Pollution and Control, 2003
The particulates may contain oxides or iron, manganese, aluminum, calcium, magnesium, or silicon [17]. Some of these are incinerated prior to leaving the EAF, but much of these must be removed from the exhaust gas stream. Draft hoods are normally used to control the particulate emissions from the EAF process. Fabric filters (baghouses) are commonly used to capture these emissions. NOx emissions from supplemental burners can be significant because of the high gas temperatures in an EAF. Another pollutant generated by EAFs that is somewhat unique is a massive amount of vibration and noise in the vicinity of the vessel, depending on its size. The arcing between the electrodes causes the vibrations and noise, which can be cumulatively disturbing to the operators and personnel in the vicinity.
III Resource Recovery and Incineration
Published in Susan E. M. Selke, Packaging and the Environment, 1994
Fabric filters, also called baghouses, pass the exhaust gases through bag-shaped fabric filters which trap particulates. Trapped particles are removed mechanically. Though they tend to be highly effective in removing particulates [99.99 percent or greater (Clarke, 1987a)], reliability problems have been common when they have been used alone, with bags deteriorating faster than expected, clogging, or resulting in fires or explosions. However, combinations of dry scrubbers and baghouses have been quite successful (Walsh and O'Leary, 1986). Baghouses are categorized according to the method by which the cake of collected particulates is removed from the bag. Shaker baghouses use energetic shaking of the bag. Reverse air systems blow a reverse air stream to gently collapse the bag, crack the dust cake, and allow it to fall down into a hopper. Pulse-jet baghouses use high pressure compressed air to crack the cake and throw it from the hopper. Bag cleaning intervals range from several minutes to several hours, with the bags being cleaned in place (Frillici and Schwarz, 1991).
Non-In Situ Soil Treatment Technologies
Published in G. Mattney Cole, Assessment and Remediation of Petroleum Contaminated Sites, 2018
Technical Basis: Contaminated soil is fed into a stripping chamber where high temperature gases cause hydrocarbon contaminants to volatilize. Vapors are entrained and either burned or collected. Typically the stripper chamber is rotated or agitated to provide good contact between soil particles and hot gases. Vapors from the stripper chamber are passed through a flame (an afterburner), a catalytic converter, or a carbon filter. The choice depends on whether the unit is mobile or fixed. Exhaust gases can be passed through a wet scrubber or baghouse to remove fine particulates, then vented to the atmosphere (ESI, 1990).
Measurement of transient nanoparticle emissions of pulse-jet cleaned filters applying an engine exhaust particle sizer
Published in Aerosol Science and Technology, 2022
Peter Bächler, Jörg Meyer, Achim Dittler
Baghouse filters are state of the art technology for the reduction of particulate matter emissions of technical facilities, where high raw-gas concentrations occur and have to be separated from dust-laden gas streams (e.g., municipal waste incineration, cement plants, etc.) (Dowd and Bump 1979). Filter elements (e.g., filter bags) are arranged in baghouses in varying numbers, dependent on the cleaning duty (raw-gas volume flow, concentration, dust-type, etc.) (Schmidt 1998). During filter operation, dust is separated at the surface of the filter medium, what leads to the formation of a dust cake with high separation efficiency. Assuming correct filter installation and no major leaks, the emission drops to a zero level with an established dust cake (Bach and Schmidt 2007; Kurtz, Meyer, and Kasper 2017). In order to enable continuous and economic filter operation, the filter elements are periodically regenerated (e.g., via jet-pulse; Lu and Tsai 1998). Regeneration detaches the dust cake from the surface of the medium, leaving it unprotected and prone to particle penetration until a sufficient dust cake is established during operation (Binnig, Meyer, and Kasper 2009). This leads to a distinct emission behavior, where transient emissions with high intensity occur after filter regeneration. Dependent on operating conditions and the filter medium, the emission can be only detectable over a timespan of several seconds (Bächler et al. 2020). Nanoparticles themselves can pose a challenge in baghouse filtration, as they cause clogging of the filter medium at an increased rate, so that cleaning efficiency is lowered and the residual pressure drop after regeneration increases until stable operation is no longer possible (Cirqueira, Tanabe, and Aguiar 2017; Khirouni et al. 2020).