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Show 7 Table 2 Salient Features of a 400x0-Mesh Size Fraction of the Test Coal Analysis As Received Moisture-Ash-Free Proximate & Ultimate, Wl % Moisture 1.1 - Volatile Matter 25.4 28.3 Fixed Carbon 64.6 71.7 Ash 9.1 - Hydrogen 4.2 4.7 Carbon 77.8 86.6 Sulfur 0.8 0.9 Nitrogen 1.2 1.3 Oxygen 5.8 6.5 Higher Heating Value, 8tu/1b 13,558 15,099 Rosin-Rammler Mean Weight Size, J.1m 18 - NOx Emissions and Coal Pyrolysis and Combustion. Table 3 shows the pyrolysis and combustion efficiency and NOx emissions results obtained from this study. The coal pyrolysis efficiency of 32.5% represents a 15°", enhancement over the ASTM volatile matter yield of 28.3°",. The combustion results indicate, as expected, that: (1) coal combustion efficiencies (CCE) were higher for fuel-lean cases than for fuel-rich cases (CCE=95-97% for A -1.9 vs. CCE=74-76°", for A-O.9); and (2) the corresponding NOx emissions were 185 and 110 ppm. As such, the test conditions utilized set a good stage for comparing air toxies emissions in terms of un-staged high NOx vs. staged low NOx firing conditions. Organic Air Toxies Results. The results from coal pyrolysis in an argon atmosphere are summarized in Figures 3 and 4. The benzene spectrum (Fig. 3), which was obtained on-line with a Fourier Transform Infra-Red (FTIR) spectrometer, shows a measurable concentration of this compound during volatile matter evolution phase. The coal tar, obtained from condensation of volatile products in a methylene chloride bath, was subsequently shot into a Gas Chromatograph in liquid form. Results, shown in Figure 4, also indicate measurable concentrations of PAH compounds, in addition to |
