The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM...The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.展开更多
Continuous measurements of speciated atmo- spheric mercury （Hg）, including gaseous elemental mer- cury （GEM）, particulate mercury （PHg）, and reactive gaseous mercury （RGM） were conducted in Guizhou Pro- vince,...Continuous measurements of speciated atmo- spheric mercury （Hg）, including gaseous elemental mer- cury （GEM）, particulate mercury （PHg）, and reactive gaseous mercury （RGM） were conducted in Guizhou Pro- vince, southwestern China. Guiyang Power Plant （GPP）, Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant （GAP）, and Guiyang Forest Park （GFP） in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers （Tekran 2537A） were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/ impactor, KCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ±28.3 ng·m-3 and the lowest 6.1 ± 3.9 ng·m-3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m-3 and the mini- mum average 55.9 pg·m-3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m-3 was measured at GPP, and the lowest level of 20.5 pg·m-3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pol- lution dominates RGM.展开更多
文摘The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.
基金support was provided by the National Natural Science Foundation of China(No.40773067)
文摘Continuous measurements of speciated atmo- spheric mercury （Hg）, including gaseous elemental mer- cury （GEM）, particulate mercury （PHg）, and reactive gaseous mercury （RGM） were conducted in Guizhou Pro- vince, southwestern China. Guiyang Power Plant （GPP）, Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant （GAP）, and Guiyang Forest Park （GFP） in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers （Tekran 2537A） were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/ impactor, KCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ±28.3 ng·m-3 and the lowest 6.1 ± 3.9 ng·m-3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m-3 and the mini- mum average 55.9 pg·m-3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m-3 was measured at GPP, and the lowest level of 20.5 pg·m-3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pol- lution dominates RGM.
