Abstract. Comprehensive field measurements are needed to understand the mercury emissions from Chinese power plants and to improve the accuracy of emission inventories. Characterization of mercury emissions and their behavior were measured in six typical coal-fired power plants in China. During the tests, the flue gas was sampled simultaneously at inlet and outlet of selective catalyst reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfurization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured power plants ranged from 17 to 385 μg/kg. The mercury mass balances for the six power plants varied from 87 to 116% of the input coal mercury for the whole system. The total mercury concentrations in the flue gas from boilers were at the range of 1.92–27.15 μg/m3, which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is influenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control device systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66–94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.
After the ultra-low emission(ULE) transformation, the emissions of ULE coal-fired power plants in China have been reduced greatly. However, considering the total amount of emissions, coal-fired power plants are still among the largest sources. And there may still have great potential in the removal of colored plume and some unconventional pollutants such as condensable particles matter (CPM) and sulfur trioxide (sulfuric acid mist). Though in cold days, hazes occur frequently. Besides, low-temperature condensation is conducive to the condensation and removal of vapor, CPM and sulfur trioxide in the flue gas. In this paper, a new method of low-temperature flue gas emission is proposed for coal-fired power plants in severe cold areas. The flue gas is cooled by ambient air, and discharged without reheating, and remarkable effects can be achieved in removing the pollutants. The technical feasibility and environmental compliance of applying this method to a power plant in cold weather have been analyzed. The results show that low-temperature emission of flue gas for coal-fired power plants in winter is effective in water-saving, emission reduction of pollutants and elimination of wet plume.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.