Emissions measurement particulates

TTie system can be used for continuous measurement of the mass concentration at a single point for up to 12 hours, for traverse measurements of stack particulate mass concentrations using sample probe extensions, with the mass transducer up to 6 m in the stack, or for intermittendy measuring particulate mass concentrations of emission gases for long-term readings (e.g.. 30-sec samples every 60 minutes. ... 

The CMB-dlspersion model comparisons had Identified data base deficiencies that would not have been apparent had the model predictions been compared only to measured particulate mass. Correction of the emission inventory and model inadequacies was, however, critical to improving the model s source Impact predictions and to the strategy s success. 

The results reported by Carrasco et al. (1998) revealed that nearly all studied metal emissions, measured at the exit of a cement kiln stack, were significantly higher when a blend of 80 wt% coal + 20 wt% TDF was combusted instead of pure coal. Especially notable are increased emissions in Cr, Mn, Cu, Zn, and Pb (Table 9). The exception to this trend is Hg, which exhibited a 30% reduction in its emission rate when the coal + TDF mixture was burned. The data further document reductions in NO and organic compound emissions, including PAHs, where the most drastic decrease was observed for dioxins and furans. On the other hand, emissions of CO, S02, and HC1 increased considerably with the addition of TDF (Table 9). The total particulate emissions from combustion of the blend were only slightly greater than those from pure coal. Carrasco et al. (1998) used their data to model atmospheric dispersion of the emitted contaminants in the vicinity of the... 

Three sets of tests have occurred at Saginaw Steering and Gear. The first, in 1983, measured particulate, SOz and N0X, in Boiler 6.7 All three pollutants increased at 10 percent TDF compared to baseline.7 In 1988, boiler 2 was tested for particulate, S02, S03, at baseline and 5 percent TDF. Particulate, S03, and NOx increased, while S02 decreased.9 In 1989, particulate emissions from boiler 2 were tested given this time at four TDF levels 0, 10, 15, and 20 percent.8 Particulate emissions rose throughout the series.8 Table 7-3 summarizes all these data. 

The emission measurements during this testing included N0X, smoke, particulate and PNA. N0X was determined by a non-disper-sive infrared analyzer, and smoke by the Bacharach test. Both the particulates and PNA were sampled by a source assessment sampling system (SASS). The SASS system isokinetically samples a fraction of the stack gas and traps particulates in a series of cyclones, which classify the particulate by size. Final filtration is through a fiberglass filter mounted in an oven heated to 200°C to prevent condensation of acids. In this program, the cyclones were not used, since previous work (3) had shown the particulate from coal-derived fuel oils to be small, with an average diameter on the order of 0.4 /um. The PNA which is not deposited on the particulate is collected on XAD-2 resin after the gas has been cooled to 15-20°C. PNA analyses were carried out on a combined extract from the particulate, XAD-2 resin, other condensates in the system, and the solvent rinses used to clean the SASS system. 

The relation between ambient levels and precursor emissions is somewhat easier to identify for particulates than for ozone, because the chemical composition of individual particulates provides evidence for their origin sulfate particulates are associated with sulfur dioxide emissions organic particulates with specific VOCs, and so on. A variety of statistical methods have been used to identify source types for particulates based on chemical composition, especially in terms of trace metal components (e.g., Henry, 1992 Seinfeld and Pandis, 1998). This type of analysis requires sophisticated measurements of the chemical composition of individual particulates, rather than the more common measurement of summed concentrations. Statistical methods have also been used to gain information about ozone and ozone precursors (e.g., Buhr et al., 1995 Stehr et al., 2000). 

As with all atmospheric species, trace metal emissions undergo atmospheric transport and dilution before they reach a particular receptor site. Mathematical models can be constructed based on the fundamentals of atmospheric chemistry and physics that will track the contributions from many emission sources as they undergo atmospheric transport. Indeed, the development of such models will receive considerable attention in this book. In the case of particulate emissions, an alternative is available. It is possible to attack the source contribution identification problem in reverse order, proceeding from measured particulate concentrations at a receptor site backward to the responsible emission sources (see Chapter 24). The unique metals content of the emissions from each source type is viewed as a fingerprint for the presence of material from that source in an ambient aerosol sample. 

Today, emissions, including particulate matter, are regulated in many countries and specified separately for the various emission parameters and vehicle and fuel types. Particulate mass emissions are measured by gravimetric methods over engine or vehicle test cycles, which consist of a sequence of speed and load... 

DOF (1994) Diario Oficial de la Federacion Norma Oficial Mexicana NOM-025-SSA1-1993 Dreiseidler AM, Baumbach G, Straub D (2000) Results of fine particulate matter emission measurements at different industrial plants. J Aerosol Sci 31(suppl 1) S242-S243 Eastwood P (2008) Particulate emissions from vehicles. Wiley, West Sussex EU (2008) Air quality standards. European Commission Directive 2008/50/EC. 

A schematic presentation and a picture of the experimental setup are shown in Figs. 14.16 and 14.17, respectively, which include a medium-duty Diesel engine, Diesel oxidation catalyst (DOC)/Diesel particulate filter (DPF), and two SCR catalysts in series at downstream of the DOC/DPF. For the emission measurement system, a Horiba MEXA 7500 gas analyzer was used to measure the tailpipe NO emissions. Three Siemens VDO (NGK) NO sensors and two Delphi ammonia sensors were used to provide feedback information to the SCR controller and to monitor the emission levels at different locations as shown in Figs. 14.16 and 14.17. 

A ntunber of internal process measures were introduced. This will lead to reduced discharges of COD to water, reduced emissions of particulates and sulfur dioxide to air, and reduced discharges of odorous substances. See also Fig. F-24. 

Source sampling of particulates requites isokinetic removal of a composite sample from the stack or vent effluent to determine representative emission rates. Samples are coUected either extractively or using an in-stack filter EPA Method 5 is representative of extractive sampling, EPA Method 17 of in-stack filtration. Other means of source sampling have been used, but they have been largely supplanted by EPA methods. Continuous in-stack monitors of opacity utilize attenuation of radiation across the effluent. Opacity measurements are affected by the particle size, shape, size distribution, refractive index, and the wavelength of the radiation (25,26). 

Method 25 applies to the measurement of volatile organic compounds (VOC) as nonmethane organics (TGNMO), reported as carbon. Organic particulate matter will interfere with the analysis, and, therefore, in some cases, an in-stack particulate filter will be required. The method requires an emission sample to be withdrawn at a con-... 

SW-846, is used to measure emissions of semivolatile principal organic constituents. Method 0010 is designed to determine destruction and removal efficiency (DRE) of POHCs from incineration systems. The method involves a modification of the EPA Method 5 sampling train and may be used to determine particulate emission rates from stationary sources. The method is applied to semivolatile compounds, including polychlorinated biphenyls (PCBs), chlorinated dibenzodioxins and dibenzofurans, polycyclic organic matter, and other semivolatile organic compounds. 

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