Showing papers by "Wei-Ping Pan published in 2010"
TL;DR: A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting ofSO(3), was applied in SO( 3) tests in three full-scale utility boilers, and tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(1) sampling.
Abstract: The formation of sulfur trioxide (SO(3)) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM(2.5). Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(3) during SO(3) sampling. A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO(3), was applied in SO(3) tests in three full-scale utility boilers. For the two units burning bituminous coal, SO(3) levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO(2) to SO(3,) and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO(3) estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO(3) removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO(3) across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO(3).
110 citations
TL;DR: In this article, a lab-scale simulated scrubber that was designed and built in the laboratory at Western Kentucky University's Institute for Combustion Science and Environmental Technology is described.
43 citations
TL;DR: Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation and selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits ofAir pollutant and mercury removal.
Abstract: Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.
39 citations
TL;DR: In this article, the preparation and photocatalysis of TiO 2 -ZnS/fluoropolymer fiber composites was investigated, and the degradation rate of methylene blue was considerably higher than that of either TiO2 or TiOsnS nanoparticles system under visible-light irradiation.
36 citations
TL;DR: This work focuses on determining the leachability of selected elements sequentially leached in four extraction solutions: water, 1M ammonium acetate, 3M hydrochloric acid and 50% hydrofluoric acid.
23 citations
TL;DR: In this paper, a lab-scale simulated scrubber was used to simulate absorbing and dissolving of elemental mercury (Hg 0 ) in the flue gas across WFGD systems, where transition metal ions with low chemical valence were used to prepare solutions with concentration levels of mmol·L −1.
12 citations
TL;DR: In this article, the Ontario Hydro Method (OHM) was used to determine mercury speciation in the combustion flue gas across wet FGD systems, which can increase overall mercury removal efficiencies through WFGD systems.
Abstract: The Ontario Hydro Method (OHM) recommended by the United States Environmental Protection Agency (EPA) was used to determine mercury speciation in the combustion flue gas across wet FGD systems. Four coal-fired units with wet FGD systems were chosen to evaluate mercury speciation and mercury removal efficiencies through these wet FGD systems. Chlorine content in coal had been suggested as a main factor that affects mercury speciation in flue gas. It is shown that the higher the chlorine concentration in coal is, the higher the percentage of oxidized mercury (Hg2+) is removed in wet FGD systems, which can increase overall mercury removal efficiencies through wet FGD systems. The selective catalyst reduction (SCR) system has a function of oxidizing elemental mercury (Hg0) to oxidized mercury. A higher percentage of oxidized mercury in the total vapor mercury at the FGD inlet is observed when SCR is in service. Therefore, higher overall mercury removal efficiencies through wet FGD are attained. Because of different wet FGD operating conditions, there are different mercury removal efficiencies in different units. Elemental mercury reemission took place when a fraction of oxidized mercury absorbed in the slurry is reduced to elemental mercury, and Hg0 is reemitted from stack, which results in decreases in mercury removal efficiencies through wet FGD systems.
8 citations